WO2013191267A1

WO2013191267A1 - Control device for internal combustion engine

Info

Publication number: WO2013191267A1
Application number: PCT/JP2013/067026
Authority: WO
Inventors: 亮草壁; 安部　元幸; 歩畑中; 青野　俊宏; 広津　鉄平; 坂本　英之; 隆夫福田; 秀治江原; 豊原　正裕; 西岡　明
Original assignee: 日立オートモティブシステムズ株式会社
Priority date: 2012-06-21
Filing date: 2013-06-21
Publication date: 2013-12-27
Also published as: JP2018197548A; JP6805209B2; JP2016196893A; JP5982484B2; JP6383760B2; JPWO2013191267A1

Abstract

Provided is a control device with which individual variation in the amount of fuel injected by the fuel injection devices for each cylinder is detected at the fuel injection devices, and the injection pulse width and the current waveform applied to a solenoid are adjusted so as to reduce the individual variation in the fuel injection devices, thereby enabling control of the injection amount at intermediate lift wherein the valve body does not contact the fixed core. The voltage between the terminals of a solenoid (105) is detected for the fuel injection device of each cylinder, and with the change in the induced electromotive force due to the change in the acceleration of the armature (102) when the valve body (114) moves from the open state to the closed state and the armature (102) separates from the valve body (114) after the valve body (114) contacts the valve seat (118), as the time at which the second-order differential value of the voltage between the terminals of the solenoid (105) is the maximum, the timing for completing the closing of the valve body (114) is determined.

Description

Control device for internal combustion engine

The present invention relates to a control device for a fuel injection valve used in an internal combustion engine.

In recent years, there has been a demand for improvement in fuel consumption (fuel consumption rate) in internal combustion engines due to tightening of carbon dioxide emission regulations and concerns about exhaustion of fossil fuels. For this reason, efforts are being made to improve fuel efficiency by reducing various losses of the internal combustion engine. Generally, when the loss is reduced, the output required for engine operation can be reduced, and therefore the minimum output of the internal combustion engine can be reduced. In such an internal combustion engine, it is necessary to control and supply a small amount of fuel corresponding to the minimum output.

Patent Document 1 includes a mover that is held by a valve body so that it can be displaced relative to the valve body in the driving direction of the valve body, thereby suppressing bounce at the time of collision of the valve body and reducing the fuel injection amount. A precisely controllable fuel injection valve is disclosed.

In recent years, downsizing engines that have been reduced in size by reducing the displacement and obtaining output by a supercharger have attracted attention. In the downsizing engine, the pumping loss and the friction can be reduced by reducing the displacement, so that the fuel efficiency can be improved. On the other hand, a sufficient output can be obtained by using a supercharger, and a reduction in compression ratio due to supercharging can be suppressed and fuel efficiency can be improved by an intake air cooling effect by performing direct in-cylinder injection. . For example, in the fuel injection device used for this downsizing engine, fuel can be injected over a wide range from the minimum injection amount corresponding to the minimum output obtained by reducing the displacement to the maximum injection amount corresponding to the maximum output obtained by supercharging. There is a need to expand the control range of the injection amount.

Generally, the injection amount of the fuel injection device is controlled by the pulse width of the injection pulse output from the ECU (engine control unit). Increasing the injection pulse width increases the injection amount, and shortening the injection pulse width decreases the injection amount, and the relationship is substantially linear. However, there is a delay from the timing at which the ECU outputs a drive pulse to the fuel injection device to the timing at which the fuel injection device actually opens, and the delay is caused by dimensional tolerances or aging deterioration of each fuel injection device. It is known that there are variations in valve timing and valve opening speed. Similarly, for the valve closing, there is a delay after the ECU finishes outputting the drive pulse until the fuel injection device actually performs the valve closing operation. There is variation. Particularly in the region where the width of the injection pulse is short, that is, when the amount of fuel commanded by the ECU is small, variations in valve behavior due to delay of the on-off valve, dimensional tolerance for each fuel injection device, aging deterioration, etc. are actually injected. Therefore, it is difficult to accurately control the fuel injection amount.

Here, in order to reduce the variation in the injection amount for each fuel injection device and the minimum injection amount that can be controlled by the ECU, the variation in the valve operation and the variation in the injection amount are determined by the ECU for each fuel injection device of a plurality of cylinders. It is necessary to detect and correct the injection amount. In the fuel injection control device disclosed in Patent Document 2, it is disclosed to detect the vibration of the on-off valve by providing an acceleration sensor for each fuel injection device. In Patent Document 2, focusing on the phenomenon that the magnetic material constituting the magnetic circuit is magnetically saturated and the inductance of the magnetic circuit changes due to the rapid reduction of the air gap between the mover and the fixed core. The valve opening timing is detected by detecting the timing at which the second-order differential value is switched from negative to positive.

In general, Patent Document 3 discloses that a first-order differential value of a solenoid energization current or voltage is measured to detect the behavior of the mover from a change in inductance.

JP 2007-218204 A Japanese Patent Application Laid-Open No. 2001-221121 US Patent Application Publication No. 2011/0170224

In the technique disclosed in Patent Document 1, individual differences such as dimensional tolerance at the time of manufacture that are different for each fuel injection device are not taken into consideration. Further, in the fuel injection device in which the mover and the valve body are configured separately as in Patent Document 1, the current supply to the solenoid is stopped and the valve closing operation is performed from the state in which the valve body is open. After the valve body reaches the valve closing position and stops, the mover moves away from the valve body and performs a parabolic motion in the valve closing direction. Even if the technique described in Patent Document 3 using the first-order differential value of the current or voltage applied to the solenoid is small, the actual behavior of the valve closing cannot be detected as a change in inductance. Further, as in Patent Document 3, in a fuel injection device in which a mover for generating a magnetic attractive force to open and close a valve body and a valve body for opening and closing a fuel passage are integrated, When the valve body is closed from the open state, the movement of the mover also stops at the timing when the valve body stops at the closed position, and the speed change of the mover increases, making it easy to detect changes in inductance. The valve body can be detected by the method using the first-order differential value of the voltage, but the total weight of the valve body and the mover collides with the valve seat sealing the fuel when performing the valve closing operation. Will easily bounce between the valve seat and the valve body will inject unintentionally after the valve closes, increasing the unburned particles PM (Particulate Matter) and the number of PN (Particulate Number) including soot there is a possibility.

Further, in the detection method of the on-off valve timing using the acceleration sensor disclosed in Patent Document 2, a new sensor is provided for each fuel injection device, resulting in an increase in cost. Further, in the valve opening detection method focusing on the phenomenon that the air gap between the mover and the stopper is reduced and magnetically saturated as disclosed in Patent Document 2, the saturation magnetic flux density is reached at the timing when the mover collides with the stopper. Without the condition, the magnetic field generated inside the magnetic circuit composed of the solenoid and the magnetic material stator, mover, etc. has a linear relationship to some extent, for example, the voltage applied to the solenoid Unless the current value flowing through the solenoid is low and the condition is small, the change in magnetic resistance caused by the reduction of the air gap between the mover and the stator cannot be regarded as the change in current. In fuel injection devices that require high response and high efficiency in order to perform minute injection amount control, the voltage applied to the solenoid is high, so the suction surface before such a mover collides with the stopper Consideration about the influence on the valve opening detection under the condition that the magnetic flux density of the magnet becomes large is not always sufficient. Further, sufficient consideration has not been given to the method for detecting the valve closing timing.

An object of the present invention is a cause of variation in injection amount among individual fuel injection devices in which a mover and a valve body are configured as separate members while suppressing increase in cost, or variation in injection amount caused by aging degradation. Another object of the present invention is to provide a control device that can detect the actual operation timing of the valve body.

In order to solve the above problems, a control device of the present invention closes a fuel passage by contacting a valve seat, opens a fuel passage by leaving the valve seat, and is capable of relative displacement in the drive direction of the valve body. A mover held by the valve body; a solenoid and a magnetic core that urges the mover to exert a magnetic attractive force in a valve opening direction; and supplying the current to the solenoid, the magnetic core and the moveable In a control device for controlling a fuel injection valve that drives the valve element and the mover in the valve opening direction by applying the magnetic attraction force between the valve and the child, the current supplied to the solenoid is cut off. When the valve seat comes into contact with the valve body, a change in induced electromotive force due to an increase in the distance between the mover and the magnetic core is detected as a voltage value between the solenoid terminals. Do

According to the present invention, since it is possible to detect the actual operation timing of the valve body of the fuel injection device in which the mover and the valve body are configured separately, the control device that causes the fuel injection amount variation It is possible to recognize the deviation between the input of the drive signal and the actual valve behavior on the control device side.

It is a longitudinal cross-sectional view of the fuel injection device in one Example of this invention, and the figure which shows the structure of the drive circuit and engine control unit (ECU) connected to this fuel injection device. It is the figure which showed the relationship between the general injection pulse which drives a fuel-injection apparatus, the timing of the drive voltage and drive current which are supplied to a fuel-injection apparatus, and a valve body displacement amount. It is the figure which showed the relationship between the injection pulse width Ti output from ECU in FIG. 2, and fuel injection quantity. It is the figure which showed the relationship between the injection pulse width Ti and the fuel injection quantity of the general fuel injection apparatus with individual variation in injection quantity characteristic. It is the figure which showed the valve behavior in each

point

401, 402, 403, 431, 432 in FIG. It is a figure which shows the structure of the drive circuit and engine control unit in one Example of this invention. The relationship between the injection pulse, the drive current supplied to the fuel injection device, the

switching elements

605, 606, and 607 of the fuel injection device, the voltage between the terminals of the solenoid, the behavior of the valve body and the mover, and time in one embodiment of the present invention is shown. It is a figure. 1st derivative of valve body displacement amount, inter-terminal voltage, and inter-terminal voltage after stopping injection pulses of three fuel injection devices whose valve body behavior is fluctuating due to the influence of variation in dimensional tolerance in one embodiment of the present invention It is the figure which showed the relationship between the value after a value and the 2nd-order differential value of the voltage between terminals, and the injection pulse stop. It is the table | surface which showed the correspondence of the displacement between the needle | mover after an injection pulse stop which is the detection principle of the valve closing completion timing in one Example of this invention, and the magnetic flux which passes a needle | mover, and a voltage. . In the intermediate lift condition in one embodiment of the present invention, when the injection pulse width is changed in the same fuel injection device, the injection pulse, the drive current, the valve body displacement, the inter-terminal voltage, the second-order differential value of the inter-terminal voltage, and It is the figure which showed the relationship of the time after turning on the injection pulse. When driving fuel injection devices having different dimensional tolerances in one embodiment of the present invention, the voltage across the terminals of the solenoid, the drive current, and the current 1 under the conditions for detecting the valve closing completion timing when the valve body 114 reaches the target lift It is the figure which showed the relationship between the time after a floor differential value, a valve body displacement amount, and the injection pulse were turned ON. It is the figure which showed the initial stage magnetization curve and return curve of the magnetization curve (BH curve) of a general magnetic material. It is the figure which showed the circuit structure which drives the fuel-injection apparatus in 3rd Example of this invention. It is the figure which showed the relationship between the injection pulse width Ti in the 3rd Example of this invention, the voltage _VL , the 2nd-order differential value of the voltage _VL , and the time after the injection pulse OFF. It is the figure which showed the structure of the drive device in 4th Example of this invention. It is the figure which showed the frequency gain characteristic of the analog differentiating circuit 1501 in 4th Example of this invention. Among the cases where the fuel injection device is driven by the control method in the fifth embodiment of the present invention, the voltage between the terminals of the fuel injection device, the drive current, and the valve body when the valve body is used while being held at the target lift position for a certain period of time. It is the figure which showed the relationship of the valve opening direction force (valve opening force) and the valve closing direction force (valve closing), the amount of valve-body displacement, and time which are the acting force which acts on. While the valve body reaches the target lift by the control method in the fifth embodiment, the voltage between the terminals, the driving current, and the acting force acting on the valve body in the operating state when the minimum injection amount is performed are in the valve opening direction. It is the figure which showed the relationship between force (valve opening force), force in the valve closing direction (valve closing), valve body displacement, and time. According to the control method in the fifth embodiment, the injection pulse width Ti, the driving current, and the acting force acting on the valve body when operating with the intermediate lift that realizes the injection amount smaller than the injection amount by the operation shown in FIG. It is the figure which showed the relationship between the force (valve opening force) of a valve opening direction, the force (valve closing) of a valve closing direction, a valve body displacement amount, and time. FIG. 20 is a diagram showing the relationship between the injection pulse width and the injection amount when using the current waveforms of the control methods of FIGS. 17 to 19 in the fifth embodiment. Among the control methods in the sixth embodiment of the present invention, the voltage between the terminals and the drive current when the valve body is driven by reaching the target lift, and the force in the valve opening direction (the opening force acting on the valve body) It is the figure which showed the relationship between valve force), the force (valve closing) of a valve closing direction, the displacement amount of a valve body, and time. While the valve body reaches the target lift by the control method in the sixth embodiment, the inter-terminal voltage, the drive current, the valve body driving force, the valve body displacement amount and the time in the operation state when the minimum injection amount is performed It is the figure which showed the relationship. According to the control method in the sixth embodiment, the injection pulse width Ti, the drive current, and the acting force acting on the valve body when operating with the intermediate lift that realizes the injection amount smaller than the injection amount by the operation shown in FIG. It is the figure which showed the relationship between the force (valve opening force) of a valve opening direction, the force (valve closing) of a valve closing direction, a valve body displacement amount, and time. FIG. 24 is a diagram collectively showing a series of operations of FIGS. 21 to 23 in the sixth embodiment. FIG. 24 is a diagram showing the relationship between the injection pulse width and the injection amount when using the current waveforms of the control methods of FIGS. 21 to 23 in the sixth embodiment. Among the cases where the fuel injection device is driven by the control method in the seventh embodiment of the present invention, the voltage between the terminals of the fuel injection device, the drive current, and the valve body when the valve body is used while being held at the target lift position for a certain period of time. It is the figure which showed the relationship between a driving force, the valve body displacement amount, and time. While the valve body reaches the target lift by the control method in the seventh embodiment, the inter-terminal voltage, driving current, valve body driving force, valve body displacement amount and time in the operating state when the minimum injection amount is performed It is the figure which showed the relationship. With the control method in the seventh embodiment, the injection pulse width Ti, the driving current, the valve body driving force, and the valve body displacement when operating with an intermediate lift that realizes an injection amount smaller than the injection amount by the operation shown in FIG. It is the figure which showed the relationship between quantity and time. Among the cases where the fuel injection device is driven by the control method in the eighth embodiment of the present invention, the voltage between the terminals of the fuel injection device, the drive current, and the valve body when the valve body is used while being held at the target lift position for a certain period of time. It is the figure which showed the relationship between a driving force, the valve body displacement amount, and time. While the valve body reaches the target lift by the control method in the eighth embodiment, the inter-terminal voltage, the drive current, the valve body driving force, the valve body displacement amount and the time in the operation state when the minimum injection amount is performed It is the figure which showed the relationship. With the control method in the eighth embodiment, the injection pulse width Ti, the driving current, the valve body driving force, and the valve body displacement when operating with an intermediate lift that realizes an injection amount smaller than the injection amount by the operation shown in FIG. It is the figure which showed the relationship between quantity and time. It is the figure which showed the relationship between the voltage between terminals of a fuel-injection apparatus, a drive current, valve-body drive force, a valve-body displacement amount, and time when driving a fuel-injection apparatus by the control method in 9th Example. In the case where the fuel injection device is driven by the control method in the ninth embodiment, the relationship between the time after the injection pulse width Ti is stopped and the voltage between the terminals, the drive current, the mover driving force, and the mover displacement is shown. FIG. It is the figure which showed the relationship between the voltage between terminals of a fuel-injection apparatus, a drive current, valve-body drive force, a valve-body displacement amount, and time when driving a fuel-injection apparatus by the control method in 10th Example. It is the figure which showed the relationship between the voltage between terminals of a fuel-injection apparatus, a drive current, a valve-body drive force, a valve-body displacement amount, and time when driving a fuel-injection apparatus by the control method in 11th Example. It is the schematic at the time of mounting the fuel-injection apparatus described in Embodiment 1 to 11 in the 12th Example, and its control method in a cylinder direct injection type engine. It is the figure which showed the cross-section of the fuel-injection apparatus in 13th Example. It is an enlarged view of the drive part structure in the state which the valve body of the fuel-injection apparatus in 13th Example is stationary in the valve closing position. It is an enlarged view of the drive part structure in the state which the valve body of the fuel-injection apparatus in 13th Example is still in the valve opening position (target lift). It is the figure which showed the relationship between the injection pulse width of the fuel-injection apparatus in 13th Example, the valve body displacement amount, and time. It is the figure which showed the circuit structure which drives the fuel-injection apparatus in 14th Example. The driving current in the fourteenth embodiment, the voltage V _HL between the Hi side reference terminals of the fuel injection device 640, the voltage V _H between the Hi side terminal of the fuel injection device 640 and the ground potential (GND), and the fuel injection device 640 It is the figure which showed the relationship between the voltage _VL between ground potential (GND side terminal and ground potential (GND)), and the time after an injection pulse stop. It is the figure which showed the detail of the multiplexer arrange | positioned at the drive device in 14th Example.

Hereinafter, the configuration and operation of the fuel injection device and the drive device thereof according to an embodiment of the present invention will be described with reference to FIGS.

First, the configuration and basic operation of the fuel injection device and its driving device will be described with reference to FIG. 1 is a longitudinal sectional view of a fuel injection device for injecting fuel into an engine cylinder, and an EDU (drive circuit: engine drive unit) 121 and an ECU (engine control unit) 120 for driving the fuel injection device. It is a figure which shows an example of a structure. In the present embodiment, ECU 120 and EDU 121 are configured as separate parts, but ECU 120 and EDU 121 may be configured as an integral part. In the present embodiment, an in-vehicle engine, particularly an in-cylinder direct injection engine that injects fuel into an engine cylinder, will be described, but the present invention is not limited to this.

ECU 120 takes in a signal indicating the state of the engine from various sensors such as an intake air amount sensor and calculates an appropriate injection pulse width and injection timing according to engine operating conditions. The injection pulse output from the ECU 120 is input to the drive circuit 121 of the fuel injection device through the signal line 123. The drive circuit 121 controls the voltage applied to the solenoid 105 and supplies a drive current. The ECU 120 communicates with the drive circuit 121 through the communication line 122 and can switch the drive current generated by the drive circuit 121 based on the pressure of the fuel supplied to the fuel injection device and the operating conditions of the engine. . The drive circuit 121 can change the control constant by communication with the ECU 120, and the current waveform changes according to the control constant.

A structure and operation | movement are demonstrated using the longitudinal cross-section of a fuel-injection apparatus.
The fuel injection device shown in FIG. 1 is a normally closed electromagnetic valve (electromagnetic fuel injection device), and in a state where the solenoid (coil) 105 is not energized, the valve body 114 is a spring that is a first spring. 110 is biased toward the valve seat 118 and is in close contact with the valve seat 118. In this closed state, the mover 102 is urged toward the fixed core 107 (in the valve opening direction) by the zero position spring 112 as the second spring, and is provided at the end of the valve body 114 on the fixed core side. In close contact with the regulating portion 114a. In this state, there is a gap between the mover 102 and the fixed core 107. A rod guide 113 that guides the rod portion 114b of the valve body 114 is fixed to a nozzle holder 101 that forms a housing. The valve body 114 and the mover 102 are configured to be relatively displaceable in the moving direction of the valve body 114 (open / close valve direction), and are contained in the nozzle holder 101. The rod guide 113 constitutes a spring seat for the zero position spring 112. The force by the spring 110 is adjusted at the time of assembly by the pushing amount of the spring retainer 124 fixed to the inner diameter of the fixed core 107. The urging force of the zero position spring 112 is set smaller than the urging force of the spring 110.

In the fuel injection device, the fixed core 107, the mover 102, and the yoke 103 constitute a magnetic circuit, and there is a gap between the mover 102 and the fixed core 107. A magnetic diaphragm 111 is formed in a portion corresponding to the gap between the mover 102 and the fixed core 106 of the nozzle holder 101. The solenoid 105 is attached to the outer peripheral side of the nozzle holder 101 while being wound around the bobbin 104.

A rod guide 115 is provided in the vicinity of the end of the valve body 114 opposite to the restricting portion 114 a so as to be fixed to the nozzle holder 101. The rod guide 115 may be configured as the same part as the orifice cup 116. The valve body 114 is guided in movement in the valve axis direction by two rod guides, a first rod guide 113 and a second rod guide 115.

An orifice cup 116 in which a valve seat 118 and a fuel injection hole 119 are formed is fixed at the tip of the nozzle holder 101, and the internal space (fuel passage) in which the movable element 102 and the valve body 114 are provided is sealed. is doing. Although a plurality of fuel injection holes 119 are provided in this embodiment, only one fuel injection hole 119 may be provided.

Fuel is supplied from above the plane of the fuel injection device, and the fuel is sealed by a seal portion and a valve seat 118 formed at the end of the valve body 114 opposite to the regulating portion 114a. When the valve is closed, the valve body is pushed in the closing direction by a force corresponding to the seat inner diameter at the valve seat position by the fuel pressure.

When a current is passed through the solenoid 105, a magnetic flux is generated between the mover 102 and the fixed core 107, and a magnetic attractive force is generated. When the magnetic attractive force acting on the mover 102 exceeds the sum of the load due to the spring 110 and the force due to the fuel pressure, the mover 102 moves upward. At this time, the movable element 102 moves upward together with the valve body 114 while being engaged with the restricting portion 114 a of the valve body 114, and moves until the upper end surface of the movable element 102 collides with the lower surface of the fixed core 107.

As a result, the valve body 114 is separated from the valve seat 118, and the supplied fuel is injected from the plurality of fuel injection holes 119.

When the energization to the solenoid 105 is cut off, the magnetic flux generated in the magnetic circuit disappears and the magnetic attractive force disappears. When the magnetic attractive force acting on the mover 102 disappears, the valve body 114 is pushed back to the closed position in contact with the valve seat 118 by the load of the spring 110 and the force of the fuel pressure.

In a state where the valve body 114 is stationary at the target lift position, that is, in a valve open state, the movable element 102 and the fixed core 107 collide with one or both of the movable element 102 and the fixed core 107 against the annular end surface facing each other. Protrusions that serve as parts are provided. Further, in the valve open state, the protrusion has a gap between the movable element 102 or the surface of the fixed core 107 other than the protrusion of the movable element 102 or the fixed core 107, or the fixed core 107 side. One or more fuel passages in which the fluid can move in the outer diameter direction and the inner diameter direction of the protrusions are provided. In general, martensitic or ferritic stainless steel with good magnetic properties has low material hardness and strength. In martensitic stainless steel, magnetic properties decrease when heat treatment is performed to increase the hardness. There is a case. Therefore, in order to prevent wear of the protrusion due to the collision between the movable element 102 and the fixed core 107, a plating process such as hard chrome plating may be performed on the end surface provided with the protrusion. In the operation in which the valve body 114 is pushed back to the closed position, the mover 102 moves together while being engaged with the regulating portion 114a of the valve body 114.

In the fuel injection device of the present embodiment, the valve body 114 and the movable element 102 are the moment when the movable element 102 collides with the fixed core 107 when the valve is opened and the moment when the valve element 114 collides with the valve seat 118 when the valve is closed. When the relative displacement is generated for a very short time, the bounce of the movable element 102 with respect to the fixed core 107 when the valve is opened and the bounce of the valve body 114 with respect to the valve seat 118 when the valve is closed are exerted.

Here, the spring 110 urges the valve body 114 in the direction opposite to the direction of the driving force by the magnetic attractive force, and the zero position spring 112 urges the movable element 102 in the direction opposite to the urging force of the spring 110. is doing.

Next, a relationship between a general injection pulse for driving the fuel injection device, a drive voltage, a drive current (excitation current), and a valve displacement (valve behavior) (FIG. 2), and an injection pulse and a fuel injection amount The relationship (FIG. 3) will be described.

When an injection pulse is input from the ECU 120 to the drive circuit 121, the drive circuit 121 applies a high voltage 201 to the solenoid 105 from a high voltage source boosted to a voltage VH higher than the battery voltage VB, and supplies current to the solenoid 105. Is started. When the current value reaches a predetermined peak current value I _peak , the application of the high voltage 201 is stopped. The condition for stopping the application of the high voltage 201 may be set by, for example, determining the boost voltage application time Tp in advance. After that, the voltage value to be applied is set to 0 V or less, and the current value is reduced like the current 202. When the current value becomes smaller than the predetermined current value 204, the drive circuit 121 performs application of the battery voltage VB by switching, and controls the current to become the predetermined current 203. Note that the condition for applying the battery voltage VB may also be set by the elapsed time or the like.

The fuel injection device is driven by such a supply current profile. The lift of the valve body 114 is started from the application of the high voltage 201 until the peak current value I _peak or the current 203 is reached, and the valve body 114 eventually reaches the target lift position. After reaching the target lift position, due to the collision between the mover 102 and the fixed core 107, the valve element 114 performs a bouncing action against the biasing force of the spring 110 and the fuel pressure, and eventually the magnetic attractive force generated by the current 203 By balancing with the force in the valve opening direction of the zero position spring 112, the valve body 114 is stopped at a predetermined target lift position and is in a stable valve opening state. That is, since the valve body 114 is configured to be relatively displaceable with respect to the mover 102, the valve body 114 is displaced beyond the target lift position. On the other hand, in the case of a fuel injection device having a movable valve in which the valve body 114 and the movable element 102 are integrated, the displacement amount of the valve body 114 is not larger than the target lift position, and the movable element after reaching the target lift. The amount of displacement between the valve body 102 and the valve body 114 is the same. In the case of a fuel injection device in which the movable element 102 and the valve body 114 are integrated, an integral part (hereinafter referred to as a movable valve) serves as a component part of the magnetic circuit to generate a suction force and open / close the valve seat 117. Has two functions.

Next, the relationship between the injection pulse width Ti and the fuel injection amount will be described. When the injection pulse width Ti does not reach a certain time, the magnetic attractive force acting on the movable element 102 does not exceed the force in the valve closing direction acting on the valve body 114, so the valve body 114 does not open and the fuel Is not jetted. The force in the valve closing direction is the product of the urging force from the spring 110 acting on the valve body 114, the contact diameter of the valve body 114 and the valve seat 118 in the closed state (hereinafter referred to as the seat diameter), and the fuel pressure. It is the force by the fuel pressure shown by. In the condition where the injection pulse width Ti is short, for example, 301, the valve body 114 is separated from the valve seat 118 and starts to lift, but since the valve body 114 starts to close before reaching the target lift position, The injection amount decreases with respect to the one-dot chain line 330 extrapolated from the straight line region 320. Further, at the pulse width of the point 302, the valve closing starts immediately after reaching the target lift position, and the trajectory of the valve body 114 becomes a parabolic motion. Under this condition, the kinetic energy of the valve element 114 in the valve opening direction is large, and the magnetic attraction force acting on the mover 102 is large. The injection amount increases. The injection pulse width of the point 303, since the bound amount of the valve body 114 starts closing at time t ₂₃ as a maximum, working repulsive force when the movable element 102 and the stationary core 107 colliding the mover 102, The valve closing delay time from when the injection pulse is turned off to when the valve is closed is reduced, and as a result, the injection amount is smaller than the one-dot chain line 330. Point 304 is the state such as bouncing of the valve body starts closing timing t ₂₄ immediately after the convergence, at point 304 is larger than the injection pulse width Ti, injection of fuel according to the increase in the injection pulse width Ti The amount increases linearly. In the region from the start of fuel injection to the pulse width Ti indicated by a point 304, even if the valve body 114 does not reach the target lift or the valve body 114 reaches the target lift, the bounce of the valve body is stable. Therefore, the injection amount varies, and the injection amount cannot be controlled as output from the ECU 120. In order to reduce the minimum injection amount that can be controlled from the ECU 120, the region in which the fuel injection amount increases linearly as the injection pulse width Ti increases is increased, or the injection pulse width Ti is greater than 304. It is necessary to correct the injection amount in a non-linear region where the relationship between the small injection pulse width Ti and the injection amount is not linear.

In the general drive current waveform as described with reference to FIG. 2, the bounce of the valve body 114 generated by the collision between the movable element 102 and the fixed core 107 is large, and by starting the valve closing in the middle of the bounce of the valve body 114, Non-linearity occurs in the region of the short injection pulse width Ti up to the point 304, and this non-linearity is one of the causes of deterioration of the minimum injection amount. Therefore, in order to improve the nonlinearity of the injection amount characteristic under the condition that the valve body 114 reaches the target lift, it is necessary to reduce the bounce of the valve body 114 that occurs after reaching the target lift position. In addition, since the behavior of the valve body 114 varies due to the dimensional tolerance, the timing of contact between the movable element 102 and the fixed core 107 differs for each fuel injection device, and the collision speed between the movable element 102 and the fixed core 107 varies. Therefore, the bounce of the valve body 114 varies for each individual fuel injection device, and the individual variation of the injection amount increases.

A first embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a graph showing the relationship between the injection pulse width Ti and the individual variation in the injection amount caused by the component tolerance of the fuel injection device. FIG. 5 is a diagram showing the relationship between the displacement amount of the valve element 114 due to individual variations in the injection amount in FIG. 4 and the relationship between the displacement amount of the valve element 114 and the time at each injection pulse width. FIG. 6 is a diagram showing details of the drive device 121 and the ECU (engine control unit) 120 of the fuel injection device. FIG. 7 shows an injection pulse, a drive current supplied to the fuel injection device, switching

elements

605, 606, and 607 of the fuel injection device, voltages between terminals of the solenoid, the valve body 114, and the mover 102 in one embodiment of the present invention. It is the figure which showed the relationship between behavior and time. FIG. 8 shows the displacement amount of the valve body, the inter-terminal voltage, the terminal after stopping the injection pulse width Ti of the three fuel injection devices whose valve body behavior is fluctuated due to the influence of the variation in dimensional tolerance in one embodiment of the present invention. It is the figure which showed the relationship between the 1st-order differential value of the voltage between terminals, the 2nd-order differential value of the voltage between terminals, and the time after an injection pulse stop. FIG. 9 illustrates the displacement (gap) between the movable element 102 and the fixed core 107 after the injection pulse is stopped, which is the detection principle of the valve closing completion timing in one embodiment of the present invention, and the relationship between the movable element 102 and the fixed core 107. It is the table | surface which showed the correspondence of the magnetic flux (phi) which passes the attraction | suction surface between, and the voltage V. FIG. 10 shows the injection pulse, drive current, valve displacement, inter-terminal voltage, and inter-terminal voltage when the injection pulse width Ti is changed in the same fuel injection device under the intermediate lift condition in one embodiment of the present invention. It is the figure which showed the relationship between the time after turning a 2nd-order differential value and an injection pulse into ON. FIG. 11 shows the voltage between the terminals of the solenoid under the condition of detecting the valve closing completion timing when the valve body 114 reaches the target lift when driving the fuel injection device having different dimensional tolerances in one embodiment of the present invention. It is the figure which showed the relationship between electric current, the electric current 1st-order differential value, the valve body displacement amount, and the time after turning ON the injection pulse. FIG. 12 is a diagram showing an initial magnetization curve and a return curve of a magnetization curve (BH curve) of a general magnetic material.

First, the relationship between the injection amount at each injection pulse width Ti and the displacement amount of the valve body 114 and the relationship between the individual variation of the injection amount and the displacement amount of the valve body 114 will be described with reference to FIGS. The individual variation in the injection amount is caused by the influence of the component tolerance of the fuel injection device and the fluctuation of environmental conditions, that is, the fuel pressure supplied to the fuel injection device, the battery voltage source of the drive device, and the voltage value of the boost voltage source. This is caused by fluctuations in the current value supplied to the solenoid 105. The fuel injection amount of the fuel injected from the injection hole 119 of the fuel injection device is a fuel seat portion that is determined by the amount of displacement of the valve body 114 when the total cross-sectional area of the plurality of injection holes determined by the diameter of the injection hole 119 is the same. The injection amount is determined by the cross-sectional area of the flow path through which the fuel flows. FIG. 4 shows an individual Q _u having a large injection amount and an injection amount with respect to an individual Q _{c in} which the injection amount becomes the median of the design in a region where the injection pulse width is small when a constant fuel pressure is supplied to the fuel injection device. It is the figure which described individual _Ql with small.

4 and 5, the relationship between the injection amount at each injection pulse width Ti of the individual Q _c and the displacement amount of the valve body 114 under the condition of an injection pulse width t _{41 with} a certain injection amount is used. Will be described. The displacement amount of the valve body 114 under the condition of the point 401 where the injection pulse width Ti is small becomes a solid line 501, and before the valve body 114 reaches the target lift, the injection pulse width Ti is turned OFF and the valve body 114 is closed. The valve body 114 becomes a locus of parabolic motion. Next, at a point 402 where the injection amount becomes larger than the one-dot chain line 430 extrapolated from a linear region in which the relationship between the injection pulse width Ti and the injection amount is substantially linear, the displacement amount of the valve body 114 becomes larger than the solid line 501. The valve body 114 does not reach the target lift position, but starts to close as shown by a one-dot chain line 502, and becomes a parabolic trajectory like the solid line 501. Next, at a point 403 where the injection amount becomes smaller than the one-dot chain line 430, after the movable element 102 collides with the fixed core 107, the valve body 114 starts to close, and a locus as shown by a two-dot chain line 503 is obtained. The valve closing delay time from when the injection pulse width Ti is turned OFF to when the valve body 114 comes into contact with the valve seat 118 is smaller than that of the one-dot chain line 502, and as a result, the point 403 is compared with the point 402. The injection amount becomes smaller. Further, the displacement amounts of the valve body 114 at the

points

432, 401, and 431 of the respective Q _u , Q _c , and Q _l at the injection pulse width Ti of t _{41 in} the figure are shown as 506, 505, and 504. When the injection pulse width 500 at the timing t ₄₁ is input to the drive circuit, the valve opening start timing of the valve body 114 after the injection pulse width is turned ON due to the individual difference in the dimensional tolerance of the fuel injection device 640 is t _51. , T ₅₂ , and t ₅₃ . When given the same injection pulse width in the solid provided in each cylinder, an early individual Q _u is the valve opening start timing, the amount of displacement 504 of the valve body 114 at the timing t ₅₄ to turn OFF the injection pulse width Become the largest. Even after the injection pulse width is turned OFF, the movable element 102 continues to be displaced by the residual magnetic attraction force accompanying the residual magnetic flux due to the kinetic energy and eddy current, and the kinetic energy and magnetic attraction of the movable element 102 are continued. opening direction of force by force, the valve body 114 at a timing t ₅₇ drops below the force of the valve closing direction initiates the closing. As shown by the displacement amounts 504, 505, and 506 of the valve body, the individual whose valve opening start timing is earlier has a larger lift amount of the valve body 114, and after the injection pulse width is turned OFF until the valve body 114 is completely closed. The valve closing delay time increases. Therefore, if the individual variations in the valve opening start timing or the valve closing completion timing of the fuel injection device of each cylinder can be detected or estimated by the drive circuit 121 or the ECU 120, the lift amount can be controlled by the intermediate lift, and the individual injection amount can be controlled. The variation can be reduced, and the injection amount can be stably controlled even in the intermediate lift region.

The configuration of the drive circuit of the fuel injection device in the first embodiment and the method for detecting the individual variation of the displacement amount of the valve body 114, which is the cause of the individual variation of the injection amount, will be described with reference to FIGS. FIG. 6 is a diagram showing a circuit configuration for driving the fuel injection device. The CPU 601 is incorporated in the ECU 120, for example, and calculates an appropriate pulse width of the injection pulse width Ti (that is, the injection amount) and injection timing according to the operating conditions of the internal combustion engine, such as the intake air amount and the rotational speed, and the communication line 604 The injection pulse width Ti is output to the drive IC 602 of the fuel injection device. Thereafter, the switching

ICs

605, 606, and 607 are switched ON and OFF by the driving IC 602, and a driving current is supplied to the solenoid 105 of the fuel injection device.

The switching element 605 is connected between a high voltage source higher than the voltage source VB input to the drive circuit and a terminal on the high voltage side of the solenoid 105. The switching

elements

605, 606, and 607 are configured by transistors such as FETs, for example. The boosted voltage VH, which is the voltage value of the high voltage source, is 60 V, for example, and is generated by boosting the battery voltage by the booster circuit 614. The booster circuit 614 is configured by, for example, a DC / DC converter or the like, but may be configured by a coil 630, a transistor 631, a diode 632, and a capacitor 633. In the latter booster circuit, when the transistor 631 is turned on, the battery voltage VB flows to the ground potential 634 side. However, when the transistor 631 is turned off, a high voltage generated in the coil 630 is statically passed through the diode 632 and flows to the capacitor 633. Charge is accumulated. The transistor is repeatedly turned on and off until the boosted voltage VH is reached, and the voltage of the capacitor 633 is increased. The switching element 607 is connected between the low voltage source VB and the high voltage terminal of the fuel injection device. The low voltage source VB is, for example, a battery voltage, and the voltage value is about 12 to 14V. The switching element 606 is connected between the low-voltage side terminal of the solenoid 105 and the ground potential 615. The driving IC 602 detects the current value flowing through the solenoid 105 by the

current detection resistors

608, 612, and 613, and switches the switching

elements

605, 606, and 607 on and off according to the detected current value. A drive current is generated. As the

current detection resistors

608, 612, and 613, it is preferable to use a shunt resistor that is a highly accurate resistor with a small resistance value from the viewpoint of improvement in current detection accuracy and cost and reliability. In particular, in the case of the fuel injection device, since the resistance values of the

resistors

608, 612, and 613 are sufficiently smaller than the resistance value of the solenoid 105, the influence of the loss generated in the

resistors

608, 612, and 613 is small.

Diodes

609 and 610 are provided to interrupt the current. The CPU 601 communicates with the drive IC 602 through the communication line 603, and can switch the drive current generated by the drive IC 602 depending on the pressure of fuel supplied to the fuel injection device and the operating conditions.

6 and 7, the configuration of the drive circuit in the first embodiment and the switching timing of the switching element and the inter-terminal voltage of the fuel injection device for generating the exciting current flowing in the fuel injection device, the valve body 114 The relationship between the displacement amounts will be described.

FIG. 7 shows the injection pulse width Ti and drive current (excitation current) output from the CPU 601, the switching circuit 605 included in the drive circuit 121 and ECU 120, the switching element 606, the ON / OFF timing of the switching element 606, and the solenoid. It is the figure which showed the voltage between 105 of terminals, and the displacement amount of the valve body 114. FIG.

At timing t _71, when the injection pulse width Ti than CPU601 is input to the drive IC602 via the communication line 604, next to the switching element 605 and the switching element 606 is ON, by applying a higher boosted voltage VH than the battery voltage, the drive current The current is rapidly supplied to the solenoid 105. When the current reaches the peak current value I _peak , both the switching element 605, the switching element 606, and the switching element are turned OFF, and the diode 609 and the diode 610 are energized by the back electromotive force due to the inductance of the solenoid 105, and the current is a voltage source. The current fed back to the VH side and supplied to the solenoid 105 rapidly decreases from the peak current value I _peak as a current 702. Note that when the switching element 606 is turned ON during the transition period from the peak current value _Ipeak to the current 703, the current due to the back electromotive force energy flows to the ground potential side, and the current gradually decreases. Thereafter, when the timing _t73 is reached, the switching element 606 is turned on again, the switching element 607 is switched on and off, and the current 703 is controlled so as to hold the current value at or near the current value 704. After the current 703 is held for a certain time, when the ejection pulse is turned off, both the switching element 606 and the switching element 607 are turned off. When both of the switching

elements

606 and 607 are turned off, no current can flow to the ground potential (GND) side so far. Therefore, the voltage of the terminal on the voltage source side is increased by the back electromotive force due to the inductance of the solenoid 105, and the ground potential is increased. Feedback is made from the (GND) side to the high voltage source via the diode 609, the solenoid 105, and the diode 610, and charges are accumulated in the capacitor 633. At this time, the current supplied to the solenoid 105 rapidly decreases from the current 703, but due to the influence of the eddy current generated in the magnetic circuit composed of the fixed core 107, the movable element 102, and the yoke 103, Until the magnetic flux in the magnetic circuit disappears, the magnetic attraction force remains in the fuel injection device 640. Due to the influence of the residual magnetic flux caused by the eddy current, the tail voltage 705 is generated in the voltage between the terminals of the solenoid 105, and the process in which the eddy current disappears and the magnetic attractive force decreases is measured as the voltage V _inj between the terminals of the solenoid 105. can do.

Next, the behavior of the valve body 114 and the mover 102 after the application of the injection pulse width Ti is stopped will be described. When the injection pulse width Ti is turned OFF, the magnetic attractive force generated in the movable element 102 is reduced, and the magnetic attractive force acts on the valve body 114 and the movable element 102 in the valve closing direction (force by the fuel pressure and the spring 110). The valve body 114 and the mover 102 start to close in conjunction with each other at a timing smaller than the resultant force of the load. The valve body 114 and the movable element 102 is until contact with the valve seat 118 the same behavior, the valve body 114 is a timing t ₇₆ in contact with the valve seat 118, the movable element 102 is spaced from the valve body 114, Parabolic movement in the valve closing direction. After that, the zero position spring 112 urging the movable element 102 in the valve opening direction makes contact with the valve body 114 again when the movable element 102 reaches the timing t ₇₇ , and the movable element 102 is located at the position where the displacement amount is zero. Movement stops.

Further, when the valve body 114 and the movable element 102 are closed from the open state, the voltage V _inj between the terminals of the solenoid 105 is detected by the CPU 601 or the IC 602. A potential difference with respect to the ground potential 615 may be detected and detected by the CPU 601 or the IC 602 via an A / D converter mounted on the CPU 601 or the IC 602. The A / D converter may be mounted in the ECU 120 as an element different from the IC 602 and the CPU 612. The inter-terminal voltage V _inj may be detected by a potential difference between the voltage source VH and VB side terminals of the solenoid 105 and the ground potential 615 side terminal. With this configuration, the change in acceleration of the movable element 102 due to the movable element 102 being separated from the valve element 114 at the moment when the valve element 114 starts to close from the opened state and contacts the valve seat 117. _Can be detected as a change in induced electromotive force generated in the inter-terminal voltage V _inj, and the inter-terminal voltage V _inj can be detected as a digital signal via the A / D converter mounted on the IC 602 or the CPU 612. . Further, as shown in FIG. 7, the inter-terminal voltage V _inj has a maximum negative voltage from the boosted voltage −VH to VH. When the boosted voltage VH is 60V, a potential difference of 120V is generated. Become. Here, since the A / D converter has a limit of a measurable range, it is necessary to reduce the voltage to a voltage value that can be input to the A / D converters of the CPU 601 and the IC 602. Therefore, it is preferable to place two resistors in series between the

measurement terminals

641 and 642, _{divide the} voltage V _inj between the terminals, and input the voltage across the resistor to the CPU 601 or the IC 602. As a result, the detection voltage does not exceed the range that can be measured by the A / D converter, and an A / D converter having a low resolution can be employed, thereby reducing the cost. At this time, in order to suppress the heat generation of the resistor used for voltage division, the resistance value of the resistor used for voltage division may be sufficiently larger than the resistance value of the solenoid 105 of the fuel injection device.

Next, referring to FIGS. 6, 8, and 9, the explanation of the drive circuit in the first embodiment and the injection body which is one of the causes of individual variation in the injection amount are turned off, and then the valve body 114 is moved to the valve seat. The detection principle of the valve closing delay time until contact with 118 will be described.

FIG. 8 is an enlarged view 706 of the displacement amount of the valve body 114 of the three

individuals

1, 2, and 3 whose valve closing behavior differs depending on the dimensional tolerance of the fuel injection device, and the inter-terminal voltage V _inj in FIG. 7 and the inter-terminal voltage. It is the figure which showed the relationship between the 1st-order differential value of and the 2nd-order differential value of the voltage V _inj between terminals. FIG. 9 is a diagram showing the correspondence between the displacement between the mover 102 and the fixed core 107 (referred to as gap x) and the magnetic flux φ passing through the attraction surface between the fixed core 107 of the mover 102 and the voltage. is there.

From FIG. 8, when the injection pulse width Ti is turned OFF, the magnetic attractive force generated in the movable element 102 is reduced, and the magnetic attractive force is less than the valve closing force acting on the valve body 114 and the movable element 102. The valve body 114 starts to close at the timing. The magnitude of the magnetic resistance of the magnetic circuit is inversely proportional to the cross-sectional area and magnetic permeability in each path, and is proportional to the magnetic path length through which the magnetic flux passes. Compared to a magnetic material having good magnetic properties, the permeability of the gap between the mover 102 and the fixed core 107 is a vacuum permeability μ0 = 4π × 10 −7 [H / m], and the magnetic material Since it is very small compared to the magnetic permeability of metal, the magnetic resistance is increased. The magnetic permeability μ of the magnetic material is determined by the characteristics of the BH curve (magnetization curve) of the magnetic material due to the relationship of B = μH, and varies depending on the magnitude of the internal magnetic field of the magnetic circuit, but is generally low at a low magnetic field. The magnetic permeability increases, and the magnetic permeability increases as the magnetic field increases, and the magnetic permeability decreases at a point in time when the magnetic field exceeds a certain magnetic field. When the valve body 114 is displaced from the valve opening position, a gap x is generated between the mover 102 and the fixed core 107. Therefore, the magnetic resistance of the magnetic circuit increases, the magnetic flux that can be generated in the magnetic circuit decreases, and the mover 102 The magnetic flux passing through the suction surface on the fixed core 107 side end surface is also reduced. When the magnetic flux generated in the magnetic circuit of the solenoid 105 changes, an induced electromotive force is generated according to Lenz's law. In general, the magnitude of the induced electromotive force in the magnetic circuit is proportional to the rate of change of the magnetic flux flowing through the magnetic circuit (the first-order differential value of the magnetic flux). Assuming that the number of turns of the solenoid 105 is N and the magnetic flux generated in the magnetic circuit is φ, the terminal voltage V of the fuel injection device is expressed by an induced electromotive force term −Ndφ / dt as shown in the equation (1). It is represented by the sum of the resistance R of the solenoid 105 generated by Ohm's law and the product of the current i flowing through the solenoid 105.

When the valve element 114 comes into contact with the valve seat 118, the mover 102 is separated from the valve element 114, but the load due to the spring 110 that has been acting on the mover 102 through the valve element 114 and the fuel pressure acting on the valve element until now. The valve closing direction force no longer acts, and the mover 102 receives the load of the zero position spring 112 that is the force in the valve opening direction. That is, at the timing when the valve body 114 comes into contact with the valve seat 118, the acceleration of the mover 102 changes.

The relationship between the gap x generated between the mover 102 and the fixed core 107 and the magnetic flux φ passing through the attraction surface can be regarded as a first-order approximation relationship in a very short time. That is, the relationship between the gap x between the mover 102 and the fixed core 107 and the magnetic resistance R _x between the mover 102 and the fixed core 107 is expressed by R permeance method in which the magnetic circuit is represented by an equivalent circuit model. _x = x / (μ ₀ · Sx) {where, μ ₀ : permeability of vacuum, Sx: attracting area of mover} When the gap x increases, the mover 102 and the fixed core The distance of 107 increases, the magnetic resistance increases, the magnetic flux that can pass through the end face of the movable element 102 on the fixed core 107 side decreases, and the magnetic attractive force also decreases.
The suction force acting on the mover 102 can be generally derived by the equation (2). From equation (2), the attractive force acting on the movable element 102 is proportional to the square of the magnetic flux density B of the attractive surface of the movable element 102 and proportional to the attractive area S of the movable element 102.

From Equation (1) and FIG. 9, there is a correspondence between the voltage V _inj between the terminals of the solenoid 105 and the first-order differential value of the magnetic flux φ passing through the attraction surface of the mover 102. Further, since the gap x, which is the distance between the end face of the movable element 102 on the fixed core 107 side and the end face of the fixed core 107 on the movable element 102 side, changes, the area of the space between the movable element 102 and the fixed core 107 increases. Since the magnetic resistance of the magnetic circuit changes and, as a result, the magnetic flux that can pass through the attracting surface of the mover 102 changes, it can be considered that the gap x and the magnetic flux φ are in a first order approximation relationship in a very short time. it can. The reason why the gap x and the magnetic flux φ have a first-order approximation in a very short time is that the _total magnetic resistance composed of the fixed core 107, the movable element 102, the nozzle holder 101, and the yoke 103 is represented by _Rtotal , When the magnetic flux generated across the phi _total, by Ampere's law and permeance _{_{method, φ total = U / R total}} { However, U: magnetomotive force} can be expressed as, in the magneto-resistance R _total, the movable element This is because the magnetic resistance Rx between the fixed core 107 and the fixed core 107 is included. The total magnetic flux φtotal of the magnetic circuit can be broadly divided into a magnetic flux φ passing between the mover 102 and the fixed core 107 and a magnetic flux φmd leaking to the magnetic throttle part of the nozzle holder 101. by the magnetic diaphragm 111, the cross-sectional area of the nozzle holder is limited, in order to leak the magnetic flux phi _md can pass the magnetic flux density is the easy magnetic diaphragm 111 saturate the magnetic diaphragm 111 is limited, compared with the leakage magnetic flux phi _md Φ is sufficiently large. Therefore, since the relationship of φ _total ≈φ is established, the relationship between the gap x and the magnetic flux φ can be considered as a first order approximation in a very short time. On the other hand, when the gap x is small, the area of the space between the mover 102 and the fixed core 107 is small, so that the magnetic resistance of the magnetic circuit is small and the magnetic flux that can pass through the attraction surface of the mover 102 increases. On the other hand, when the gap x is large, the area of the space between the mover 102 and the fixed core 107 is large, so that the magnetic resistance of the magnetic circuit is large and the magnetic flux that can pass through the attraction surface of the mover 102 decreases. . Further, as shown in FIG. 9, the first-order differential value of the magnetic flux has a corresponding relationship with the first-order differential value of the gap x. Further, the first-order differential value of the terminal voltage corresponds to the second-order differential value of the magnetic flux φ, and the second-order differential value of the magnetic flux φ corresponds to the second-order differential value of the gap x, that is, the acceleration of the mover 102. Therefore, in order to detect a change in acceleration of the mover 102, it is necessary to detect a second-order differential value of the voltage between the terminals.

From FIG. 8, when the valve body 114 is displaced from the target lift position after the injection pulse width Ti is stopped, the profile of the inter-terminal voltage V _inj changes. For example, at timing t ₈₁ , the voltage V _inj between terminals changes according to the amount of displacement of the movable element 102 that moves in conjunction with the valve body 114, and the voltage V _inj between terminals increases as the gap x between the movable element 102 and the fixed core 107 _increases. Gradually approaches 0.

Since the timing t _82, t _83, t ₈₄ to the displacement amount and the valve element 114 of the valve body 114 of an individual 1, 2 and 3 at the timing t ₈₁ is in contact with the valve seat 118, there is a correlation, the timing t ₈₁ The valve closing completion timing at which the valve body 114 comes into contact with the valve seat 118 is estimated, and the valve closing delay until the valve body 114 comes into contact with the valve seat 118 after the injection pulse width Ti of the

individuals

1, 2, and 3 is stopped is estimated. The time can be detected, and the individual variation of the injection amount accompanying the change in the valve closing delay time can be estimated by the ECU 120.

Note that the configuration of the fuel injection device 640, if there monolithically movable element 102 and the valve element 114, at the moment when the valve body 114 is in contact with the valve seat 118 because the movable element 102 is stationary, the terminal voltage V _inj It is possible to estimate the amount of displacement of the valve body 114 by providing a threshold value, or to detect the valve closing completion timing with the first-order differential value of the voltage as a change in speed shown in FIG.

Further, when the movable element 102 moves away from the valve element 114 at the moment when the valve element 114 comes into contact with the valve seat 118, a change in force acting on the movable element 102 is _regarded as a change in acceleration. Can be detected. After the injection pulse width Ti is stopped, the movable element 102 is displaced from the target lift position in conjunction with the valve body 114, and the inter-terminal voltage V _{inj at} this time gradually _approaches 0 from a negative value. When the movable element 102 moves away from the valve element 114 after the valve element 114 is closed, the force in the valve closing direction that has been acting on the movable element 102 via the valve element 114 until now, that is, the load due to the spring 110 and the force due to the fuel pressure are applied. The load of the zero position spring 112 acts on the movable element 102 as a force in the valve opening direction. When the valve body 114 reaches the valve closing position and the direction of the force acting on the mover 102 changes from the valve closing direction to the valve opening direction, the second-order differential value of the inter-terminal voltage V _inj that has been increasing gently until now. Starts to decrease. By detecting the maximum value of the second-order differential value of the inter-terminal voltage V _inj with a drive circuit, it is possible to accurately detect individual variations in the displacement amount of the valve body 114. In particular, the value of the voltage V _inj between the terminals due to the displacement of the mover 102 from the valve opening position is the resistance value determined by the wire diameter and the number of windings of the solenoid 105, the specifications of the magnetic circuit, the material of the magnetic material (electricity It varies depending on the inductance determined by the low efficiency and the BH curve), the set value of the target lift of the valve body 114, the current value at the timing when the injection pulse width Ti is stopped, and due to the tolerance variation of the dimensions and set values described above. In order to estimate the valve closing delay time accurately, it is preferable to set a correction value due to the influence of the measurement error in the drive circuit 121 or the ECU 120 beforehand. For example, from equation (1), for example, the deviation value from the design median value of the resistance value of the shunt resistor for measuring the resistance value and current value of the solenoid 105 is driven for each fuel injection device 640 of each cylinder as initial information. By inputting to the apparatus, an error due to a change in the current value can be reduced, so that a change in the terminal voltage Vinj due to a measurement error can be reduced. This is because when the resistance value of the shunt resistor for current detection changes, the voltage at both ends thereof is also affected by the variation, so that the true current value at the time of current control changes for each cylinder or each driving device. It is. At this time, the resistance value of the solenoid 105 may be marked as initial information for each fuel injection device 640 so that the initial information can be read by the drive device. Also, for the method of estimating the valve closing delay time by the detection value of the terminal voltage V _inj, the detection method of the valve closing delay time due to the second order derivative of the terminal voltage V _inj, acceleration of the movable element 102 as a physical quantity Therefore, the valve closing completion timing and the valve closing delay time can be accurately detected without being affected by variations in design values, tolerances, and environmental conditions (current values).

Further, in order to detect the valve closing delay time from when the injection pulse width Ti is stopped until the valve body 114 is closed, the terminal voltage V _inj input to the IC 602 or the CPU 601 is second-order differentiated, and 2 By detecting the timing at which the floor differential value is maximized as the timing at which the valve body 114 is closed, an accurate valve closing completion timing can be detected. In addition, an active low-pass filter including an operational amplifier 620,

resistors

619 and 618, and a capacitor 617 may be configured between the measurement terminal 641 of the inter-terminal voltage V _inj of the fuel injection device 640 and the voltage input terminal 612. The change in the inter-terminal voltage V _inj detected as a change in acceleration due to the mover 102 being separated from the valve body 114 has a lower frequency than noise generated in the voltage signal. Therefore, high-frequency noise generated in the voltage V _inj between the solenoids 105 can be reduced by _{passing a} low-pass filter between the voltage V _inj between the terminals and the measurement terminal 641 and the CPU 601 or the IC 602. The detection accuracy of the valve completion timing can be increased. Further, cut-off frequency f _c of the active low-pass filter, the resistor 618 and the capacitor 618 can be set using Equation (3) below using. Depending on the configuration of the fuel injection device and the drive device, the switching timing of the

switching element

605, 606, 607, 614 and the switching element 631 for configuring the second voltage source and the value of the second voltage source differ, and as a result The frequency of noise generated in the voltage is different. Therefore, the design values of the resistor 618 and the capacitor 618 may be changed and set for each specification of the solenoid 105 and the drive circuit. Further, when the low-pass filter is configured by an analog circuit, it is not necessary to perform the filtering process digitally by the CPU 601, so that the calculation load on the CPU 601 can be reduced. Further, a signal from the

measurement terminals

641 and 642 of the inter-terminal voltage V _inj may be directly input to the CPU 601 or the IC 602 and digitally filtered. In this case, since it is not necessary to use the

resistors

618 and 619, the capacitor 617, and the operational amplifier 620, which are components of the analog low-pass filter, the cost of the driving device can be reduced. Further, the low-pass filter described above may be a primary low-pass filter including a capacitor arranged in parallel with a resistor arranged in series with the measurement terminal 641. When the primary low-pass filter is used, the cost of the driving device can be reduced because the two components of the resistor and the operational amplifier can be reduced compared to the configuration using the active low-pass filter. Moreover, the calculation method of the cut-off frequency of the primary low-pass filter can be calculated by Expression (3) when the active low-pass filter is used. Further, as a configuration of the low-pass filter, it is possible to configure a low-pass filter having a second or higher time using a coil and a capacitor. In this case, since a low-pass filter can be configured without a resistor, there is a merit that power consumption is lower than when an active low-pass filter and a primary low-pass filter are used.

The signal input to the CPU 601 or the IC 602 is triggered by the injection pulse width Ti, and the inter-terminal voltage V _{inj is} set for a preset time after the injection pulse width Ti is stopped. It is good to capture the signal. With such a configuration, the data of the inter-terminal voltage V _inj input to the CPU 601 or the IC 602 can be made the minimum data point sequence necessary for detecting the valve closing completion timing. There is an effect that the storage capacity of the memory can be reduced. Further, if the voltage differentiation process is performed at the timing of switching from the boosted voltage VH to the battery voltage VB, the timing of repeating ON / OFF of the switching

elements

605, 606, and 607, that is, the timing at which the voltage change becomes steep, Since a high-frequency signal is generated in the data, there is a possibility that the valve closing completion timing may be erroneously detected when the valve closing completion timing when the valve body 114 contacts the valve seat 118 is detected by the second-order differential value of the voltage. By determining the voltage detection period by the CPU 601 or the IC 602, erroneous detection of the valve opening completion timing can be prevented. Note that the voltage detection resistor 616 may be a shunt resistor with high resistance accuracy. In the fuel injection device drive device, the voltage across the

voltage detection resistors

612, 613, 608, and 616 provided in the drive circuit is diagnosed by the IC 602 in order to measure the current or voltage. If the resistance value differs for each individual with respect to the resistance value, an error occurs in the voltage value estimated by the IC 602, and the drive current supplied to the solenoid 105 of the fuel injection device varies for each fuel injection device of each cylinder. In addition, the injection amount variation becomes large.

Further, if the voltage V _inj between the terminals of the solenoid 105 is small at the valve closing position where the valve body 114 and the valve seat 118 are in contact with each other, the change in the voltage value due to the change in the acceleration of the mover 102 becomes relatively small. It is effective to increase the load of the spring 110 so as to shorten the valve closing delay time so that the valve closing position is reached under the condition that the inter-terminal voltage V _inj is high. Further, as the fuel pressure supplied to the fuel injection device increases, the force due to the fuel pressure acting on the valve body 114 and the mover 102 increases, and therefore the valve closing delay time becomes shorter. For example, the individual variation of each cylinder at the valve closing completion timing when the valve body 114 contacts the valve seat 118 is detected under the condition that the fuel pressure is high and the fuel pressure supplied to the fuel injection device in each cylinder is the same operating condition. good. Due to this effect, the residual magnetic flux generated in the magnetic circuit at the valve closing completion timing becomes larger than in the condition where the fuel pressure is low, and the speed when the valve body 114 collides with the valve seat 118 increases. The moment when the valve element 114 contacts the valve seat 118, the change in the acceleration of the mover 102 due to the separation of the mover 102 from the valve element 114 increases, and the change in the induced electromotive force also increases. _It becomes easy to detect the valve closing completion timing by the second-order differential value of _inj or the inter-terminal voltage V _inj . In addition, under the condition where the fuel pressure supplied to the fuel injection device 640 is high and the engine load is large, the injection amount injected during one intake stroke increases, and the influence of pressure pulsation of a pipe attached upstream of the fuel injection device As a result, the fuel pressure supplied to the fuel injection device may fluctuate. In this case, the valve closing completion timing may be detected under conditions such as idle operation where the engine load is small and the injection amount of each cylinder is the same.

In addition to the CPU 601 and the IC 602, a microcomputer for detecting the inter-terminal voltage V _inj and performing data processing may be provided in the ECU 120. When the CPU 601 detects the inter-terminal voltage V _inj and performs data processing, it is necessary to perform data processing at a high sampling rate, and when interrupt processing occurs when signals from other sensors are captured, Under conditions where the calculation load is high, it may be difficult to detect the inter-terminal voltage V _inj . Therefore, by detecting the inter-terminal voltage V _inj with a microcomputer provided in addition to the CPU 601 and performing the masking process and the differential process, the second-order differential value of the inter-terminal voltage V _inj is calculated, and the second-order differential value of the voltage Since the microcomputer has a function of detecting and memorizing the timing at which the maximum value is detected as the valve closing completion timing, the calculation load of the CPU 601 and the IC 602 can be reduced, and the valve opening completion timing can be reliably detected. In addition, the accuracy of the injection amount can be improved. This microcomputer is provided with a communication line that can communicate with the CPU 601 or the IC 602. The CPU 601 stores in the CPU 601 the information on the fuel pressure taken from the pressure sensor by the CPU 601 and the detection information on the valve closing completion timing transmitted from the microcomputer. It is good to comprise so that it may. With such a configuration, the valve closing completion timing can be detected more reliably, and the injection amount of each cylinder can be controlled more accurately.

In a normal engine, a command value from an A / F sensor (air-fuel ratio sensor) is detected by the CPU 601, and the injection pulse width is finely adjusted for each fuel injection device of each cylinder even under the same operating conditions. In the condition for detecting the valve closing completion timing, fine adjustment of the injection pulse width based on the command value from the A / F sensor is stopped, and the valve closing completion timing is detected under the condition that the same injection pulse width is supplied. . By doing so, it is possible to reduce the influence of fluctuations other than individual variations accompanying the valve operation of the fuel injection device 640, such as variations in inflow air when detecting the valve closing completion timing, and the fuel injection device 640 is closed. Individual variations in valve completion timing can be accurately detected.

Further, when the injection pulse width Ti is stopped and the valve body 114 is closed from the opened state, the valve body 114 comes into contact with the valve seat 118 after the valve body 114 or the movable element 102 starts to close. Thus, until the valve closing is completed, it is preferable to control the switching of the driving device so that the switching

elements

605, 606, and 607 of the driving device are not switched ON / OFF. With the configuration as described above, by high frequency measurement noise due to the switching of the switching

elements

605, 606, 607 to the terminal voltage V _inj it is, appears in the terminal voltage V _inj of the fuel injection device 640, the valve opening It is possible to reduce the influence that adversely affects the measurement accuracy of completion detection.

Next, a method of detecting the valve opening delay time from when the injection pulse width Ti is supplied until the valve body 114 reaches the target lift will be described with reference to FIGS. In addition, you may implement with the detection method of the valve closing delay time mentioned above, and you may implement only any one. FIG. 11 is a diagram showing a method of controlling the applied voltage for detecting the valve opening delay time. The voltage between the terminals of the three individual fuel injectors having different tolerances, the drive current supplied to the solenoid 105, and the drive current are shown. It is the figure which showed the relationship between 1st-order differential value of this and a valve body displacement amount.

From FIG. 7, the boosted voltage VH is applied to the solenoid 105 of the fuel injection device until the drive current reaches the peak current I _peak . After that, when the boosted voltage VH in the negative direction is supplied like the current 702 or the switch 606 is turned on and the voltage of 0 V is supplied, the slope of the current 702 is reduced, and the current 704 is supplied. To reach.

When the drive current is compared with the valve displacement of the valve body 114 and the mover 102, the valve body 114 has reached the target lift before the drive current reaches the current value 704. As the inter-terminal voltage V _inj until the valve body 114 reaches the target lift, a positive boost voltage VH, a voltage 0V, or a negative boost voltage VH is applied. Under the condition that the voltage value is 0V, As the gap between the movable element 102 and the fixed core 107 is reduced, the magnetic resistance changes, and changes in inductance and magnetic flux cannot be detected by voltage. Further, under the condition where the positive boost voltage VH is applied, by using the boost voltage VH, the charge accumulated in the capacitor 633 so far decreases, and the voltage value of the boost voltage VH decreases. At this time, in order to revert the voltage of the boosted voltage VH to the initial voltage value preset in the ECU 120, if the boosted voltage VH falls below the threshold value of the set voltage, the switch of the booster circuit is stored in order to accumulate charges in the capacitor. The voltage value of the boosted voltage VH may be restored by turning ON the voltage value. However, since the change due to the reduction of the magnetic gap has little influence on the voltage value with respect to the change in the voltage value, It is difficult to detect the change in magnetic flux due to the body 114 reaching the target lift by the voltage value of the boost voltage VH. Further, when performing an operation for restoring the voltage value of the boosted voltage VH, it is necessary to repeat ON / OFF of the switching element 631 of the booster circuit at a high speed cycle. The detection accuracy of valve completion timing may be adversely affected.

7 and 11, after the injection pulse width Ti is supplied, the boosted voltage VH is applied to the solenoid 105, and after reaching the peak current value _Ipeak , the negative boosted voltage VH is applied for a certain time, and the current value is After a steep fall like 1101, a constant voltage that is the battery voltage VB is applied from the battery voltage source, and the valve body 114 reaches the target lift at a timing when the constant voltage is supplied from the battery voltage VB. It is better to have a voltage configuration.

Under the condition in which the battery voltage VB is continuously applied and a constant voltage value 1102 is supplied, the voltage applied to the solenoid 105 does not change, so the mover 102 starts to lift from the closed position, and the mover 102 A change in magnetoresistance associated with a reduction in the gap with the fixed core 107 can be detected as a change in induced electromotive force. When the valve body 114 and the mover 102 start to lift, the gap between the mover 102 and the fixed core 107 is reduced, so that the induced electromotive force is increased and the current supplied to the solenoid 105 is gradually reduced as 1102. To decrease. Since the change in the induced electromotive force accompanying the change in the gap becomes small at the timing when the mover 102 reaches the fixed core 107, that is, the timing when the valve element 114 reaches the target lift (hereinafter referred to as valve opening completion timing), The value increases gradually as 1104. Although the magnitude of the induced electromotive force is affected by the current value in addition to the gap, since the change in current is small under the condition that a voltage lower than the boosted voltage VH is applied like the battery voltage VB, the gap It is easy to detect the change in the induced electromotive force due to the change in the current. In order to detect the timing at which the valve element 114 reaches the target lift for the individual 1, individual 2, and individual 3 of each cylinder of the fuel device described above, the first floor of the current is detected. Differentiation is performed, and timings t ₁₁₃ , t ₁₁₄ , and t ₁₁₅ when the first-order differential value of the current becomes 0 may be detected as the valve opening completion timing.

In addition, in a magnetic circuit in which the induced electromotive force generated by the change in the gap is small, the current may not necessarily decrease due to the change in the gap, but the current gradient changes by reaching the valve opening completion timing. By configuring so that a threshold value can be set for the first-order differential value of the current detected by the driving device, the timing when the first-order differential value of the current exceeds the threshold value can be detected as the valve opening completion timing, and the magnetic circuit, inductance, resistance The valve opening completion timing can be stably detected without being restricted by the value and current.

In addition, the detection of the valve opening completion timing is the same as the detection of the valve opening completion timing described in the separate structure of the valve body 114 and the movable element 102 even in the configuration of the movable valve in which the valve body 114 and the movable element 102 are integrated. It can be detected by the same principle.

Here, FIG. 12 shows the BH characteristics of a magnetic material used in a general magnetic circuit. From FIG. 12, the BH curve of the magnetic material has a non-linear relationship between the input magnetic field and the magnetic flux density. When an increasing magnetic field is applied to the non-magnetized magnetic material, the magnetic material begins to be magnetized and the magnetic flux density Increases until the saturation magnetic flux density Bs is reached. In this process, there is a region H1 where the gradient of the magnetic field and the magnetic flux density is large, and a region H2 where the gradient of the magnetic field and the magnetic flux density is small. Further, when the magnetic field is decreased after reaching the saturation magnetic flux density Bs, a phenomenon different from the initial magnetization curve is drawn because the phenomenon that the magnetic material is magnetized is delayed in time. In a fuel injection device, since a positive magnetic field is often repeatedly applied, a minor loop of hysteresis is often drawn between the initial magnetization curve and the return curve. Further, under the condition for detecting the valve opening completion timing, the current is increased until the peak current I _peak is reached, and after the magnetic attractive force necessary for displacing the valve body 114 can be generated in the mover 102, the valve opening is performed. It is preferable to reduce the magnetic attractive force acting on the mover 102 by rapidly reducing the drive current as in 1101 before the completion timing. Under the condition that the drive current supplied to the fuel injection device is higher than the current value necessary for holding the valve body 114 in the valve open state as the peak current value I _peak , the current value supplied to the solenoid 105 is As shown in FIG. 12, it is often located in a region H2 where the gradient of the magnetic field and magnetic flux density is small. In the first embodiment of the present invention, a magnetic attraction force necessary for opening the valve is generated in the mover 102, and then a negative boost voltage VH is applied to rapidly decrease the current as indicated by 1101. Thus, the drive current at the valve opening completion timing can be reduced, and the gradient of the magnetic field and the magnetic flux density can be increased as compared with the gradient of the magnetic field and the magnetic flux density under the condition of the peak current value _Ipeak. Has an effect that the change of the magnetic resistance accompanying the reduction of the gap between the mover 102 and the fixed core 107 can be remarkably easily detected as the change of the induced electromotive force.

In detecting the valve opening completion timing, the time after the peak current value I _peak is reached or after the application of the boost voltage VH in the negative direction is over and after the elapse of a certain time given to the drive device. It is preferable to detect only the current value in a certain period and perform the first-order differentiation process of the current value. With such a configuration, the current value changes rapidly at the timing when the boosted voltage VH is turned ON / OFF, and therefore the threshold value to be given to the drive device in advance at a time that is not the valve opening completion timing is set as the current value. The erroneous detection that the first-order differential value exceeds can be suppressed, and the detection accuracy of the valve opening completion timing can be improved.

Note that after the t ₁₁₂ the application of the negative direction of the boosted voltage VH is stopped, during a period in which a constant voltage value 1102 from the battery voltage source VB is supplied, the target current value Ih1 previously set to IC602 The period _Thhb during which the peak current value I _peak and the negative boost voltage VH are applied may be adjusted so that the peak current value I _peak is not reached. Due to this effect, when the drive current reaches the target current value Ih1 before the valve body 114 reaches the target lift, the drive device is controlled to keep the current Ih1 constant. Can pass through the 0 point repeatedly, so that it is possible to solve the problem that the change in the induced electromotive force cannot be detected by the drive current.

Further, from the state where the constant voltage value 1102 is applied, the negative boost voltage VH is applied or the voltage application is stopped (application of 0 V), and the current value reaches the current 704 in FIG. The switching

elements

605, 606, and 607 are controlled so as to have a current 703 by repeatedly turning on and off the battery voltage VB. The time from when the injection pulse width Ti is turned on until the current value Ih1 is reached varies depending on the individual difference of the valve body 114 and the variation in the valve opening completion timing accompanying the change in the fuel pressure. The magnetic attraction force when the injection pulse width Ti is stopped depends greatly on the value of the drive current when the injection pulse width Ti is turned off. When the drive current is large, the magnetic attraction force increases and the valve closing delay time increases. To increase. Conversely, if the drive current is small when the injection pulse width Ti is turned off, the magnetic attractive force is reduced and the valve closing delay time is reduced. As described above, the current value at the timing when the injection pulse width Ti is turned OFF is desirably the same current 703 for each individual under the condition for detecting the completion of the valve opening. The timing of applying the boosted voltage VH in the direction or stopping the voltage application may be controlled by the time after the injection pulse width Ti is turned ON or the time after the peak current value I _peak is reached.

The time from the supply of the injection pulse width Ti to the completion of valve opening is stored as the valve opening delay time for each fuel injection device of each cylinder, and from the central value of the valve opening delay time previously given to the CPU 601. The deviation value is calculated, the correction value of the injection pulse width Ti after the next injection is calculated according to the deviation value, and the injection pulse width Ti is determined for each fuel injection device of each cylinder based on the detection information of the valve opening delay time. It is good to correct. By correcting the injection pulse width Ti based on the detection information of the valve opening delay time, it is possible to reduce individual variations in the injection amount caused by variations in the valve opening delay time due to variations in tolerance.

The above-described voltage application method and valve opening delay time detection may be performed by setting a detection mode under specific operating load conditions such as idle operation or engine stop. By detecting the valve opening completion under the same operating conditions and calculating the valve opening delay time, fluctuations in the valve opening delay time caused by individual variations can be accurately detected. Similarly, for the valve closing delay time, the injection pulse width Ti may be corrected for each fuel injection device.

When the drive current in the solenoid 105 is stopped and the fuel injection device is closed, a gap is formed between the opposed surfaces of the movable element 102 and the fixed core 107 by a protrusion provided on the movable element 102 or the fixed core 107. Have When the mover 102 starts to close, a fluid resistance force (squeeze) that prevents the mover 102 from moving away from the fixed core 107 side by the fuel interposed between the mover 102 and the fixed core 107. Force due to the effect). The force due to the squeeze effect is proportional to the speed of the movable element 102 and increases in proportion to the cube of the height of the gap between the movable element 102 and the fixed core 107. Since the protrusion provided on the movable element 102 or the fixed core 107 repeatedly collides with the opening of the valve, the height of the protrusion decreases due to wear or deformation due to deterioration, and the force due to the squeeze effect increases and the protrusion is opened.・ The valve closing delay time may increase. Therefore, for example, the detection of the valve opening completion / closing timing is performed again every time when the engine rotation speed reaches a predetermined rotation speed set in the CPU 601, so that the opening due to deterioration of the protruding portion of the movable element 102 or the like is performed. -It is possible to reduce variations in injection amount caused by fluctuations in valve closing completion timing.

Also, the detection of the valve opening delay time and the detection of the valve closing delay time can be performed simultaneously. By simultaneously detecting the valve opening delay time and the valve closing delay time in detection modes such as idle rotation where the operating conditions of each cylinder are the same, the number of injections required for detection can be halved. Can be reduced.

Further, when the fuel pressure supplied to the fuel injection device increases, the differential pressure caused by the differential pressure of the valve body 114 and the flow velocity of the fuel flowing through the fuel seat increase, so that static pressure based on Bernoulli's theorem When the force due to the pressure drop caused by the decrease increases, the valve opening start / opening completion timing is delayed, and the valve closing start / valve completion timing is advanced. Even when the fuel pressure changes, the valve opening completion timing can be detected by detecting the timing when the differential value of the current becomes 0, as in the method for detecting the individual variation of the fuel injector. By detecting the timing at which the second-order differential value of the inter-voltage V _inj is maximized, the valve closing completion timing can be detected. Further, the valve closing completion timing can be accurately detected when the voltage V _inj between the terminals at the moment when the valve body 114 comes into contact with the valve seat 118 after stopping the injection pulse. This is because the magnetic flux that adds the attracting surface of the mover 102 that determines the magnetic attraction force of the mover 102 gradually decreases due to the influence of the eddy current after the injection pulse width is turned off. This is because the change in the induced electromotive force that changes due to the change in the acceleration of the mover 102 is relatively small when is small. Accordingly, the higher the fuel pressure supplied to the fuel injection device, the greater the force due to the fuel pressure applied to the valve body 114. Therefore, the valve is closed until the valve body 114 is closed after the injection pulse width Ti is turned OFF. The delay time can be shortened, the voltage V _inj between the terminals at the valve closing completion timing is increased, and the valve closing completion timing can be detected with high accuracy. Further, since there is a correlation between the fuel pressure of the fuel injection device 640 and the valve closing delay time, the valve closing completion timing at a low fuel pressure is estimated from the valve closing completion timing detected at a high fuel pressure. It is possible. When the fuel pressure supplied to the fuel injection device 640 changes, the differential pressure acting on the valve body 114 changes. However, the change in the differential pressure accompanying an increase in the fuel pressure changes substantially linearly, and the valve closing completion timing also changes. It changes almost linearly. Generally, when the differential pressure acting on the valve body 114 increases, the force in the valve closing direction increases, so that the valve closing completion timing is advanced, and when the differential pressure decreases, the valve closing completion timing is delayed. Therefore, by setting a correction coefficient corresponding to a change in the fuel pressure in the drive device in advance, it is possible to estimate the valve closing completion timing at a different fuel pressure from the valve closing completion timing detected at a certain fuel pressure. Therefore, it is possible to reduce the frequency of detection of the valve closing completion timing necessary for correcting the injection amount, and the processing load on the drive device can be reduced.

When the valve body 114 is in contact with the valve seat 118, the valve body 114 is subjected to a force obtained by multiplying the cross-sectional area of the contact diameter between the valve body 114 and the valve seat 118 and the fuel pressure in the valve closing direction. Work to 114. Since the force acting on the valve body 114 increases as the fuel pressure increases, the magnetic attraction force generated in the mover 102 required for the valve body 114 to start opening increases, and the value of the required drive current Also grows. By using the information from the pressure sensor attached to the fuel pipe detected by the CPU 601 and changing the setting of the current value of the drive IC 602 through the communication line 603, the peak current value is increased according to the increase in the fuel pressure. The supply period of the constant voltage 1102 necessary for increasing I _peak and detecting a change in current when the valve body 114 is lifted to the target can be set without depending on the fuel pressure. In addition, the induced electromotive force increases as the displacement amount of the valve body 114 increases, and the driving current decreases 1102 and the valve body 114 reaches the target lift, so that the induced electromotive force decreases and the driving current decreases. Since the change due to the fuel pressure of the inclination when the pressure increases can be reduced, the detection accuracy of the valve opening completion timing can be improved.

In the fuel injection device, the injection amount may be managed by adjusting the load of the spring 110 under certain fuel pressure and injection pulse conditions in order to reduce individual variations in the injection amount due to dimensional fluctuations. In this case, in the group of fuel injection devices having the same load of the spring 110, for a large injection amount, the force in the valve closing direction acting on the valve body 114 is increased by increasing the load of the spring 110. Therefore, it is preferable to adjust the valve closing delay time so as to reduce the injection amount. In addition, for an individual with a small injection amount, it is preferable to increase the injection amount by increasing the valve closing delay time by decreasing the load of the spring 110. By adjusting the set spring load 110 for each fuel injection device, four timings of valve opening start, valve opening completion, valve closing start, and valve closing completion vary for each individual. Since the influence on the behavior of the body 114 is a linear change, the four timings described above are fluctuations that are shifted by translation. Therefore, there is a strong correlation between the valve closing completion timing and the valve closing start timing, and the valve closing start timing can be calculated by multiplying the detected valve closing completion timing by a correction coefficient preset in the ECU 120. Similarly, it is possible to estimate the valve opening start timing by multiplying the detected valve opening completion timing by a correction coefficient. In addition, the valve closing start, the valve opening completion, and the valve opening start can be estimated using a plurality of different correction coefficients using the detected valve closing completion timing.

Next, a detection method of the valve closing timing under the condition of an intermediate lift where the injection pulse width is small and the valve body 114 does not reach the target lift will be described using FIG. FIG. 10 shows the relationship between the second-order differential value of the injection pulse width Ti, the displacement amount of the valve body 114, the voltage between the terminals of the solenoid 105 and the voltage between the terminals when the injection pulse width Ti is changed in the intermediate lift region. It is a figure. As shown in FIG. 10, when the injection pulse width Ti is changed to Ti1, Ti2, and Ti3, the displacement amount of the valve body 114 increases as the injection pulse width Ti increases. The higher the current value when stopping the ejection pulse width Ti, the larger the magnetic field generated inside the magnetic circuit, and the greater the magnetic attractive force acting on the mover 102 after the current is interrupted. Detection of closing completed at the intermediate lift, by detecting the terminal voltage V _inj at a certain timing t _102, multiplied by a correction coefficient set in advance to ECU120 in accordance with the detected voltage value, the The valve closing completion timing for each fuel injection device of the cylinder may be estimated and stored in the ECU 120. _{Alternatively} , even if the intermediate lift condition is _satisfied , the second-order differential value of the inter-terminal voltage V _inj is a period after the timing when the valve body 114 starts to lift and moves from the movement in the target lift direction to the movement in the valve closing direction. By detecting the maximum timing, the valve closing timing can be detected with high accuracy. In particular, the voltage value of the inter-terminal voltage _Vinj is affected by fluctuations in the tolerance of the current value supplied to the solenoid 105, the resistance and inductance of the solenoid 105, and the voltage value of the boost voltage source VH. There is a possibility that the detection accuracy of the displacement amount of the moving movable element 102 is lowered. By detecting the valve closing completion timing as the timing at which the second-order differential value of the inter-terminal voltage is maximized, the valve body 114 with the injection pulse widths Ti1, Ti2, Ti3 is not affected by the tolerance variation described above. It is possible to detect the valve closing completion timing.

First, the valve opening start timing is estimated based on the individual variation information of the valve opening completion timing obtained under the condition that the valve body 114 reaches the target lift, and the median of the valve opening start timing set in the ECU 120 in advance. Is calculated as a correction value of the injection pulse width Ti, injection is performed with the intermediate lift, and the valve closing completion timing under the condition of the intermediate lift is detected. Since there is a strong correlation between the valve closing completion timing detected by the intermediate lift and the maximum displacement amount of the valve body 114 at the intermediate lift, the correction coefficient is multiplied by the variation amount of the valve closing completion timing in each cylinder. Thus, the maximum value of the displacement amount is calculated, and the injection amount can be calculated from the passage sectional area of the fuel seat portion determined by the displacement amount. By calculating the deviation value of the injection amount under the conditions of the calculated injection amount and each injection pulse width Ti and fuel pressure set in the ECU 120, and correcting the injection pulse width Ti after the next injection, individual variations in the injection amount Can be reduced.

When performing intermediate lift driving, the valve closing completion timing at the intermediate lift is calculated by multiplying the deviation from the median deviation value of the valve closing delay time detected under the condition that the valve element 114 reaches the target lift by a correction coefficient. Can be estimated. In this case, the amount of displacement of the valve body 114 under the condition of the injection pulse width Ti at the intermediate lift can be estimated from the valve opening delay time obtained by detecting the valve opening completion timing and the valve closing completion timing. It is possible to accurately control the injection amount in the first intermediate lift drive.

In addition, after the valve element 114 is completely closed from the valve open state with the displacement shown in FIG. 7, the mover 102 continues to move in the valve closing direction. Compared to the collision speed of the valve body 114, the valve seat 118, and the collision speed when the valve body 114 is completely closed from the valve open state, the displacement amount of the valve body 114 is small as in the condition of the intermediate lift, and the injection pulse is stopped. The collision speed between the valve body 114 and the valve seat 118 becomes relatively smaller when the run-up period when the valve body 114 starts to close is shorter. For example, after the valve body 114 has been closed, under the condition that the fuel injection from the fuel injection device is divided into a plurality of times during a single intake / exhaust stroke, the next time the mover 102 moves in the valve closing direction. When the injection pulse width Ti is supplied, the valve opening start timing and valve opening completion timing of the valve element 114 differ depending on the position of the mover, and the injection amount may vary even when the same injection pulse is applied. This is because the magnetic attraction force is generated in the movable element 102 while the movable element 102 is moving in the valve closing direction or the valve opening direction after the valve element 114 is closed, so that the movable element 102 collides with the valve element 114. This is because the valve opening starts and the timing from when the injection pulse is supplied to when the valve opening is started is earlier than at the time of the first injection during the divided injection. In the intermediate lift condition, since the collision speed between the valve body 114 and the valve seat 118 is lower than when the valve is closed from the target lift, the kinetic energy of the mover 102 after the valve closing is completed becomes smaller and after the valve closing is completed. it is possible to shorten the time t ₇₇ to the movable element 102 is stationary. With this effect, it is possible to shorten the time from when the valve body 114 is closed to supply the next injection pulse width Ti under the split injection condition, so the number of split injections can be increased. . In particular, when the bore diameter of an engine such as a downsizing engine is small, the injected fuel adheres to the upper part of the piston and the bore wall surface, and is difficult to vaporize, and an increase in PM (particulate matter) becomes a problem. In such a condition, by performing divided injection to reduce the flow rate of injection at one time and reducing the penetration force of the fuel injected from the fuel injection device 640, the spray reach distance can be reduced, A technique for reducing wall adhesion is effective.

In addition, the flow rate per unit time (hereinafter referred to as static flow) in a state where the valve body 114 is opened is the total cross-sectional area of the fuel injection hole 119 and the flow path cross-sectional area of the fuel seat portion of the valve body 114. It depends on. Generally, the larger the total cross-sectional area of the fuel injection hole 119 and the flow path cross-sectional area of the seat portion, the smaller the pressure loss when the fuel flows through the flow path, so the static flow becomes larger. The flow path cross-sectional area of the seat portion is geometrically determined by the target lift of the valve body 114, and can be derived by Expression (4).

(However, S _t: target lift, D _s: seat diameter of the valve body, theta: sheet angle of the valve element 114)

From equation (4), when the target lift changes, the seat cross-sectional area changes. As a result, the static flow also changes and the injection amount changes. It is preferable that the static flow previously given to the fuel injection device can be corrected by detecting the valve opening delay time performed for each fuel injection device of each cylinder at regular intervals. The change in the valve opening delay time due to the deterioration is more influenced by the fluctuation of the target lift than the fluctuation of the valve opening force and the valve closing force. This is because the plating of the movable element 102 and the fixed core 107 is worn due to the collision between the movable element 102 and the fixed core 107, or the impact force is greatest at a location deeper than the collision surface. This is because the magnetic material of the fixed core 107 is deformed, and as a result, the target lift varies. Therefore, the valve opening delay time is detected at regular intervals, and the fluctuation time of the valve opening delay time is multiplied by the correction factor given by the drive device to convert it into the amount of change in static flow, thereby calculating the static flow. By correcting the equation, it is possible to improve the accuracy of the injection amount.

Also, under the condition that the valve body bounce that occurs after the valve body 114 reaches the target lift converges and the valve starts to close, the injection amount increases as the pulse width of the injection pulse width Ti increases, and the injection pulse width Ti The injection amount is controlled by controlling the pulse width. Under this condition, the valve opening start timing is increased by the increase in the injection pulse width from the state where the valve body 114 is stationary at the target lift position, and the valve opening completion timing is also increased. Therefore, the increase in the injection amount can be calculated by multiplying the time difference of the valve closing completion timing under different injection pulse widths by the static flow rate per unit time at the fuel pressure under the conditions. For example, even when the valve body bounce that occurs after the valve body 114 reaches the target lift is small, the period from the start of the valve body 114 to the completion of valve opening and the valve opening completion from the valve open state During this period, fuel is injected, so the minimum injection amount that can be controlled is limited by the target lift of the valve body 114 and the nozzle structure of the fuel injection device 640 such as the cross-sectional area of the fuel injection hole 119. .

On the other hand, in the condition of the intermediate lift, the lift amount of the valve body 114 can be controlled using the injection pulse width by using the detection information of the opening / closing valve delay time. Regardless of the specification, the minimum injection amount can be reduced. Therefore, when performing split injection in which the injection during one intake stroke is divided into multiple injections, and when it is desired to change the split ratio between the first injection amount and the second injection amount, the first and second split ratios For example, when the ratio is changed to 8: 2, the minimum injection amount needs to be reduced to 1/5 under the condition that the split ratio is small, assuming that the minimum injection amount required when the split injection is not performed is 1. . Under the condition of the intermediate lift, it is possible to freely change the divided injection ratio from the viewpoint of reducing the divided injection interval and reducing the minimum injection amount. Therefore, from the viewpoint of improving fuel efficiency, by performing divided injection, the contact area between the injected fuel and air is increased, and the mixing of the injected fuel and the inflowing air is promoted using the air flow in the engine cylinder. In addition, a method of changing the divided injection and the divided injection ratio is effective.

Further, as shown in FIG. 10, in the condition of the intermediate lift, since the current is often interrupted before the drive current reaches I _peak , compared with the case where the valve body 114 is used by reaching the target lift, Since the time can be shortened until the boosted voltage VH of the second voltage source returns to the initial setting value of the drive circuit, the variation of the voltage value of the boosted voltage VH in the second injection is reduced when performing the divided injection. Therefore, there is an effect that the injection amount of the first injection and the second injection in the divided injection can be made equal.

Next, effects of the embodiment of the present invention will be described. Conventionally, in the region where the width of the fuel injection pulse is short, the mover reaches the valve closing position after stopping the injection pulse due to the rebound phenomenon (bounce behavior of the mover) that occurs when the mover collides with the solid core etc. As a result, the time fluctuates, and the injection amount does not change linearly with respect to the injection pulse width, which increases the minimum controllable injection amount of the fuel injection device. In addition, the injection amount may not be stable for each individual fuel injection device due to the above-described mover bounce phenomenon, and the individual with the largest injection amount among multiple cylinders should be set as the minimum controllable injection amount. Inevitably, the minimum injection amount may be increased. Further, when the injection pulse width is further shortened from the injection pulse in the non-linear region where the relationship between the injection pulse and the injection amount is not a straight line, an intermediate lift region where the movable element and the fixed core do not collide, that is, the valve body does not fully lift. In this intermediate lift region, even if the same injection pulse is supplied to the fuel injection device of each cylinder, the lift amount of the fuel injection device varies due to individual differences caused by the dimensional tolerance of the fuel injection device. The individual variability increased, and it was difficult to use this intermediate lift region from the viewpoint of combustion stability.

Further, in the case of a fuel injection device in which the mover and the valve element are integrated, the valve element is closed by stopping the current supply to the solenoid from the state in which the valve element to which fuel is injected is open. In this case, the movable element moves in conjunction with the valve body at the moment when the valve body comes into contact with the valve seat. In this case, since the valve body repels between the valve seat and the valve seat at the moment when the valve closing state is reached, the mover that has moved in the valve closing direction during the valve closing operation becomes the acceleration and speed in the valve opening direction. . That is, the direction of the speed of the mover is reversed at the timing when the valve element is in contact with the valve seat, and the change in inductance increases, so the change in induced electromotive force also increases, and the voltage corresponding to the speed of the mover Although the valve closing completion timing can be detected by the first-order differential value of the valve, the valve body and the mover are configured separately because the combined mass of the valve element and the mover collides with the valve seat at the valve closing completion timing. As compared with the fuel injection device, the collision energy becomes larger, and the valve body may bounce between the valve seat and the unintended fuel injection even after the valve closing completion timing. In this case, the air fuel consumption becomes rich because it deviates from the target injection amount calculated by the drive unit by an unintended injection amount, so that wasteful fuel consumption occurs and fuel consumption performance deteriorates. Exhaust performance may be deteriorated due to an increase in the amount of unburned particles containing PM (Particulate Matter) and the number of PMs (Paticulate Number). In addition, when the mover and the valve body are configured as separate parts as in this embodiment, the mover moves away from the valve body and moves in the valve closing direction at the valve closing completion timing of the valve body. After that, the mover is returned to the initial position by the load of the zero position spring. That is, in the configuration of the fuel injection device according to the present invention, since the movable element 102 does not stop at the valve closing completion timing when the valve element contacts the valve seat, the change in the speed and acceleration of the movable element accompanying the valve closing of the valve element occurs. The change in velocity and acceleration cannot be detected by the first derivative of the current. According to the detection method using the maximum value and the minimum value of the second-order differential value of the inter-terminal voltage Vinj or the voltage VL in the present invention, the change in acceleration of the mover is detected as a physical quantity. By separating from the load, the load by the spring 110, which is the force in the valve closing direction that has been received through the valve body so far, and the differential pressure acting on the valve body 114 do not act on the mover, and the force in the valve opening direction Since the load of a certain zero-position spring acts on the mover, the timing at which the acceleration of the mover changes from the valve closing direction to the valve opening direction can be detected. Can be detected. Further, in the case of a fuel injection device in which the valve body and the mover are configured separately, when the valve body performs the valve opening operation from the closed state, the valve body is moved at the timing when the mover collides with the fixed core. Overshoot the target lift position away from the target. That is, when the movable element collides with the fixed core, the impact force when the movable element collides with the fixed core can be reduced by the mass of the valve body. It is possible to reduce the bounce between them and improve the fuel injection accuracy.

As described above, according to the present invention, since the actual valve behavior of each fuel injection device can be detected by the ECU, variation in the fuel injection amount is suppressed while reducing the minimum injection amount that can be controlled by the ECU. can do.

The configuration of the drive circuit of the fuel injection device and the voltage measuring method for detecting the valve closing completion timing in the second embodiment of the present invention will be described with reference to FIGS.

First, the configuration of the drive circuit in the second embodiment will be described with reference to FIG. FIG. 13 is a diagram showing a circuit configuration for driving the fuel injection device in the second embodiment. In FIG. 13, parts similar to those in FIG. 6 of the driving device in the first embodiment are described using the same reference numerals. In the drive device of FIG. 13, the difference from the first embodiment is that the voltage measurement location for detecting the valve closing completion timing is not the terminal voltage V _inj but the ground potential (GND) side of the fuel injection device 640. The voltage V _L between the terminal and the ground potential 615 is changed. With this configuration, the number of connection terminals and the A / D converter that are input to the IC 602 or the A / D converter of the CPU 601 can be reduced by one, respectively, so that the cost of the ECU 120 can be reduced. Further, since the voltage V _L is measured using the terminal 641 on the ground potential (GND) side of the fuel injection device 640, the booster circuit 614 is connected to the solenoid 105 through a coil. The influence of the power source noise on the power source side and the switching noise of the switching element 631 for accumulating charges in the capacitor 633 in the booster circuit 614 can be reduced, and the valve closing completion timing can be accurately measured.

Next, the relationship between the ejection pulse width Ti, the voltage V _L , the second-order differential value of the voltage V _L and the time after the ejection pulse OFF in the second embodiment will be described with reference to FIG. Since the voltage V _L measures the potential difference between the ground potential (GND) side terminal of the solenoid 105 and the ground potential (GND), the polarity of the voltage is reversed as compared with the inter-terminal voltage V _inj in the first embodiment. In the terminal voltage V _inj , a negative voltage is detected, but in the voltage V _L , a positive voltage is detected. Therefore, in order to detect the individual variations in the

closing completion individuals

1,2,3 in second order differential value of the voltage V _L, by detecting the value second order differential value of the voltage V _L is minimized, The valve closing completion timing can be detected.

The configuration of the drive circuit of the fuel injection device and the voltage measurement method for detecting the valve closing completion timing in Example 3 of this patent will be described.

First, the configuration of the drive circuit in the third embodiment will be described with reference to FIG. FIG. 15 is a diagram illustrating a configuration of a drive device that drives the fuel injection device according to the third embodiment. In FIG. 15, parts similar to those in FIG. 13 of the driving device in the second embodiment are described using the same reference numerals. In FIG. 15, the difference from the second embodiment is that the voltage V _L between the ground potential (GND) side terminal of the solenoid 105 and the ground potential 1415, the measurement terminal, and the CPU 601 are detected in order to detect the valve closing completion timing. In this configuration, an analog differentiating circuit 1501 including resistors R1 and R2, capacitors C1 and C2, and an operational amplifier 620 is formed. Since the voltage difference between the ground potential (GND) side terminal of the solenoid 105 and the ground potential (GND) is detected at the voltage V _L , the maximum value of the voltage value is high when application is performed from the boosted voltage VH. It becomes a voltage value. Since the capacitor C1 is disposed between the measurement terminal 641 for detecting the voltage V _L and the operational amplifier 620, the voltage input to the operational amplifier 620 can be reduced. Therefore, the A / D converter of the operational amplifier 620 and the CPU 601 is used. The withstand voltage required for the operational amplifier 620 and the CPU 601 can be reduced. Further, high-frequency noise of the driving device can be reduced by performing differential processing with an analog circuit, and time resolution necessary for the A / D converter can be input by inputting the voltage value after differential processing to the CPU 601. Can be reduced. Further, the relationship between the voltage V _L to be detected and the voltage value V ₀ input to the CPU 601 is shown in Expression (5). From the equation (5), in the analog differentiating circuit 1501, the value of the voltage V ₀ can be adjusted by appropriately adjusting the values of the resistors R1 and R2 and the capacitors C1 and C2.

FIG. 16 shows the frequency gain characteristics of the analog differentiating circuit 1501 in the third embodiment. As shown in FIG. 16, the analog differentiating circuit 1501 is a band-pass filter having a small gain at a low frequency and a small gain at a high frequency. In an analog differential circuit, the relationship between the frequency and the cause is a direct proportional relationship. Therefore, when a stepwise high frequency signal is input, there is a problem that the analog circuit amplifies it infinitely and causes the circuit to oscillate. Therefore, by determining in advance a frequency band necessary for detecting the valve closing completion timing, it is possible to stably detect only a voltage having a necessary frequency. The frequency ω and the gain G can be set using the calculation formula shown in FIG. 16, and can be arbitrarily adjusted by changing the values of the resistors R1 and R2 and the capacitors C1 and C2. It is. The frequency analysis of the voltage from when the injection pulse width Ti is stopped until the valve body 114 is completely closed may be performed in advance to set the resistors R1 and R2 and the capacitors C1 and C2.

In addition, a multiplexer is provided between the operational amplifier 620 and the measurement terminal 641, and the voltage is detected at a timing that requires detection of valve closing completion by switching the multiplexer ON / OFF based on a signal from the CPU or IC 602. Therefore, the influence of noise can be minimized, and the detection accuracy of the valve closing completion timing can be improved.

It should be noted that the analog differentiating circuit 1501 in the third embodiment may be provided in a drive circuit in another embodiment.

A control method for correcting the injection amount according to the fourth embodiment of the present invention will be described with reference to FIGS.

FIG. 17 shows the inter-terminal voltage, the drive current, and the valve of the fuel injection device when the fuel injection device is driven by the method of the fourth embodiment and the valve body 114 is used while being held at the target lift position for a certain period of time. It is the figure which showed the body drive force, the valve body displacement amount, and the relationship of time. Further, in the driving current in the figure, a conventional current waveform that is generally used is indicated by a one-dot chain line. FIG. 18 shows the relationship between the voltage between the terminals, the drive current, the valve body driving force, the valve body displacement amount, and the time in the operating state when the minimum injection amount is performed while the valve body 114 reaches the target lift. It is a figure. FIG. 19 shows the relationship between the injection pulse width Ti, the drive current, the valve body driving force, the valve body displacement amount, and the time when operating with an intermediate lift that realizes an injection amount smaller than the injection amount by the operation shown in FIG. FIG. FIG. 20 is a diagram showing the relationship between the injection pulse width Ti and the fuel injection amount q when the current waveforms of the control methods of FIGS. 17 to 19 are used.

When the injection pulse width Ti is supplied at time T1 and the valve opening signal is turned ON, the boosted voltage VH is applied to the solenoid 105. Along with this, the current flowing through the solenoid 105 gradually increases, and thereby the magnetic attractive force acting on the mover 102 rises. When the magnetic attractive force exceeds the valve closing force at time T2, the valve body 114 starts to move, and the movement gradually accelerates. Next, when the current flowing through the solenoid 105 reaches the peak current value I _peak , the application of the boost voltage VH is stopped, and at the same time, the boost voltage VH in the negative direction is applied. As a trigger for this operation performed at time T3, there is a method of determining the boosted voltage application time Tp in addition to using the fact that the peak current value _Ipeak has been reached as described above. Depending on the circuit configuration, the boost voltage VH may vary, and the wiring resistance and inductance of the fuel injection device 640 may vary. Therefore, when the boost voltage application time Tp is fixed, the peak current value I _peak varies. become. In order to give a stable valve opening force during the valve opening operation in consideration of the variation in the valve operation of the fuel injection device of each cylinder, the control method of fixing the peak current value I _peak is better. On the other hand, in order to reduce variation in time for applying the valve opening force, it is preferable to fix the boosted voltage application time Tp. After time T3, when the current reaches 0 while applying a reverse voltage to the solenoid 105, the induced electromotive force generated by the current drop disappears, but the magnetic flux remains in the magnetic circuit at that time. Then, the disappearance of the magnetic flux continues, and the voltage generated thereby is applied to the solenoid 105 in the opposite direction. At the same time as the current flowing through the solenoid 105 decreases, the magnetic attractive force acting on the mover 102 also decreases. At time T4, the magnetic attractive force crosses the valve closing force, and the valve body 114 continues to move in the lift direction. However, the acceleration is reversed to minus.

In addition, once the peak current value I _peak is reached, the current is rapidly interrupted and lowered to the holding current value Ih or less (referred to as a cutoff waveform), whereby the magnetic attractive force at the time when the valve body 114 reaches the target lift. Can be made smaller than in the case of a current waveform (referred to as a conventional waveform) that shifts from the conventional peak current value I _peak to the holding current value Ih described in the drive current of FIG. Further, since the collision speed between the valve body 114 and the fixed core 107 can be reduced by reducing the magnetic attraction force, as shown in FIG. Can be improved, the region where the relationship between the injection pulse width Ti and the fuel injection amount q is linear can be expanded in the direction where the injection amount is small, and control is possible when the valve body 114 reaches the target lift. The minimum injection amount can be reduced from the minimum injection amount 2002 having the conventional waveform to the minimum injection amount 2003 having the cutoff waveform.

Further, by setting the time during which the voltage in the driving direction after time T3 is cut off as Tc, application of the battery voltage VB in the driving direction is started at time T5 when the time is reached. By applying this voltage, a current is again supplied to the solenoid 105, and a magnetic attractive force is also generated. However, immediately after time T5, since the magnetic attractive force is in a rising phase, the force in the deceleration direction is applied to the valve body 114 until the force exceeds the valve closing force. The magnetic attraction force and the valve closing force cross at time T6. Setting the valve body 114 to reach the target lift before and after this time T6 is effective in reducing the overshoot of the valve body 114. It is. That is, using the valve opening delay time stored for each fuel injection device of each cylinder so that the time T7 when the valve body 114 is fully lifted and the magnetic attraction force are close to the valve closing force and the cross time T6, It is preferable to adjust the peak current value I _peak or the boost voltage application time Tp and the drive voltage cutoff time Tc for each cylinder.

Further, when the current cutoff waveform is used, when the injection pulse width Ti is OFF during the drive voltage cutoff time Tc, a constant current waveform is always supplied to the fuel injection device regardless of the magnitude of the injection pulse width. Therefore, there is a dead zone Tn in which the fuel injection amount q does not change even when the injection pulse width Ti is increased. In the injection amount characteristic of the cutoff waveform shown in FIG. 20, in the intermediate lift region T _harf where the valve body 114 does not reach the target lift and the region of the injection pulse width after 2003 where the valve body 114 reaches the target lift and is driven. Although the slopes of the injection pulse width Ti and the fuel injection amount q are different, since the non-linearity of the injection amount characteristic that has occurred in the injection amount characteristic of the conventional waveform has been improved, the relationship between the injection pulse width and the fuel injection amount q is It always has a positive relationship, and the fuel injection amount q increases as the injection pulse width increases. In the engine, since it is necessary to continuously increase the injection amount as the engine speed increases, in the fuel injection device 640, the fuel injection amount q increases as the injection pulse width increases. There is a need. In such an engine, by using the control method in the fourth embodiment, the required fuel injection amount q accompanying the increase in the engine speed can be appropriately controlled, and the injection amount can be easily controlled. There is. In the case of using the conventional waveform, the deviation value between the ideal straight line 2001 obtained from the required injection amount and the fuel injection amount q fluctuates in the positive and negative directions. Therefore, in the region where the injection amount characteristic is nonlinear, each injection pulse In order for the ECU 120 to grasp the relationship between the width and the fuel injection amount, the valve closing completion timing is detected for each injection pulse width Ti, and the characteristics for each fuel injection device of each cylinder are stored in the ECU 120 as the valve closing delay time. There was a need. On the other hand, in the method using the cutoff waveform, the relationship between the injection pulse width Ti and the fuel injection amount q is linear in the intermediate lift region T _harf and the region reaching the target lift. The deviation value from the required injection amount is calculated based on the detection information of the valve closing timing of two points in each region reaching the target lift and the detection information of the valve opening completion timing of one point in the region reaching the target lift. It becomes possible to reduce the calculation load of the CPU 601 or IC 602 necessary for detecting the valve operation, and simplify the algorithm for correcting individual variations in the injection amount given to the CPU 601 or IC 602. There is a merit that can be done. Further, when there is a request for an injection amount smaller than the controllable minimum injection amount 1903 under the condition that the valve body 114 reaches the target lift, an injection pulse width Ti smaller than the dead zone Tn period is used in advance. A dead zone Tn may be set in the driving device.

Specifically, when adjusting the peak current value I _peak or the boost voltage application time Tp and the drive voltage cutoff time Tc, it is possible to adjust the feedback by detecting the valve opening completion delay time Ta of each cylinder, It becomes possible to cope with individual variations and deterioration of the operating characteristics of the fuel injection device, and to realize stable operation. In the fuel injection device 640, the valve opening completion timing varies due to the influence of variation in dimensional tolerance. When the same shut-off waveform is supplied to the fuel injection device for the individual whose valve opening completion timing is late and the individual whose timing is early, the boost voltage cutoff time which is the shut-off timing of the peak current value I _peak is obtained for the individual whose valve opening completion timing is early Even if the current is cut off at T3, the movable element 102 does not decelerate in time, the collision speed between the movable element 102 and the fixed core 107 increases, and nonlinearity may occur in the injection amount characteristic. Further, in an individual whose valve opening completion timing is late, if the current is cut off at the boost voltage cutoff time T3, the magnetic attractive force necessary for the valve body 114 to reach the target lift cannot be secured, and the valve body is brought to the target lift position. Not reach. Therefore, using the information on the valve opening delay time stored in the driving device, the boosted voltage VH is cut off when the valve body 114 reaches a certain amount of displacement for each fuel injection device 640 of each cylinder from the start of valve opening. The boosted voltage application time Tp and the drive current cut-off time Tc may be adjusted so that the timing at which deceleration starts from the timing when the valve opening is completed is equivalent. Further, the peak current value I _peak automatically changes by changing the boost voltage application time Tp. However, the setting of the peak current value I _peak is changed for each fuel injection device, and the boost voltage marking time Tp is changed. You may adjust it. By adjusting the peak current value I _peak for each individual, it is possible to minimize the variation in the valve operation caused by the fluctuation of the boost voltage VH of the driving device as compared with the case where the boost voltage application time Tp is adjusted. Therefore, an appropriate deceleration timing can be adjusted for each fuel injection device of each cylinder. By appropriately correcting the peak current value I _peak and the drive voltage cutoff time Tc for each fuel injection device of each cylinder, it is possible to reduce individual variations in speed when the movable element 102 and the fixed core 107 collide. The drive sound at the time of valve opening caused by the collision can be reduced, and the engine can be silenced. Further, by reducing the collision speed between the movable element 102 and the fixed core 107, the impact force acting on the collision surface between the movable element 102 and the fixed core 107 can be reduced, and deformation and wear of the collision surface can be prevented. Therefore, a change in the target lift amount due to deterioration can be suppressed. Further, according to the effect of the present embodiment, the collision speed between the movable element 102 and the fixed core 107 can be reduced and kept constant regardless of the individual fuel injection device of each cylinder. The hardness of the material necessary for preventing deformation and wear can be reduced, and the plating process formed on the end surface on the fixed core 107 side of the mover 102 and the end surface on the mover 102 side of the fixed core 107 becomes unnecessary. As a result, significant cost reduction can be achieved. By not performing the plating process, the flow rate per unit time varies with the target lift variation caused by the variation in the plating thickness, and the fluid gap between the movable element 102 and the fixed core 107 in the valve open state. Since the variation in the squeeze force accompanying this can be suppressed, the accuracy of the injection amount can be increased.

Further, when the time T7 when the valve body 114 reaches the target lift and the magnetic attractive force can be adjusted so that the valve closing force and the cross time T6 are close, the valve body 114 rises beyond the target lift position. When the overshoot can be reduced and the overshoot is reduced, the bounce of the valve body 114 is also reduced, and the valve body 114 can be stopped immediately after time T7. When the valve body 114 is stationary at the target lift position, the fuel injected from the fuel injection device becomes a constant flow rate, and the injection amount can be increased in proportion to the time, and the injection amount can be accurately controlled. become. Further, by reducing the overshoot of the valve body 114, the collision speed when the valve body 114 collides with the mover 102 again after the overshoot can be reduced, and the impact force acting on the valve body 114 and the mover 102 is reduced. Therefore, the wear of the collision surface can be prevented, and the change in the target lift due to deterioration can be suppressed.

Further, the current cutoff is performed by correcting either the peak current value I _peak or the boost voltage application time Tp and the drive current cutoff time Tc so that the injection amount becomes equal in the fuel injection device of each cylinder. The value of the dead zone Tn of the injection amount characteristic generated when the waveform is used differs depending on the fuel injection device of each cylinder. When one value of the peak current value I _peak or the boost voltage application time Tp and the drive current cut-off time Tc are determined using the detection information, the dead zone Tn is determined. Therefore, by configuring the CPU 601 or the IC 602 so that the dead zone Tn can be set differently for each fuel injection device 640 of each cylinder, the intermediate lift region T where the injection pulse width Ti is small and the valve body 114 does not reach the target lift. Since it is possible to control by changing continuously from the _harf to the injection amount after the minimum injection amount 2003 after the valve body reaches the target lift, it is possible to perform the injection amount control in accordance with the engine operating conditions. .

The valve closing operation automatically applies the boosted voltage VH in the negative direction by cutting off the application of the battery voltage VB at the time T9 when the injection pulse width Ti that is the valve opening signal time is stopped. As a result, the current flowing through the solenoid 105 rapidly decreases, and the magnetic attractive force decreases. At time T11 when the magnetic attractive force crosses the valve closing force, the valve body 114 starts to move in the valve closing direction, and the valve closing is completed at time T12. During this time, the valve closing completion delay time Tb is measured. If there is a deviation from the standard delay time, the holding current value Ih at the target lift position can be increased or decreased to match the standard delay time. It is. In addition, when greatly correcting the variation in the valve closing completion delay time, the injection pulse width Ti is corrected, and when the valve closing completion delay time is large, the injection pulse width Ti is reduced accordingly, and the valve closing completion delay time is corrected. For smaller ones, the injection pulse width Ti is increased accordingly, so that the actual valve opening time can be controlled to the time necessary to realize the required injection amount.

FIG. 18 shows an operation state when the minimum injection amount is performed while the valve body 114 reaches the target lift by the operation procedure of this method. At the time T1, the valve opening signal is turned ON, and when the peak current I _peak is reached or when the set time Tp is reached, the application of the boost voltage VH is terminated. As a result, the boosted voltage VH in the negative direction is automatically applied, and the current flowing through the solenoid 105 rapidly decreases. As a result, the magnetic attractive force decreases, so that the valve closing force exceeds the valve opening force at time T4. After time T4, the movement of the valve body 114 is negative with respect to the valve opening direction. Instead of moving with acceleration. After the set time of the time Tc for cutting off the voltage in the driving direction, when the injection pulse width Ti that is the valve opening signal time comes at the timing of applying the battery voltage Vh, the valve body that has reached the target lift position before and after that 114 shifts to the operation in the valve closing direction while maintaining a negative acceleration, and performs the valve closing operation without stopping at the target lift position. In order to perform the operation of the minimum injection amount at the full lift, when the injection pulse width Ti is increased in the operation at this time, the time during which the valve body 114 is stationary at the target lift position is increased accordingly. There is a need. That is, ideally, at the minimum injection amount, when the stationary time at the target lift position is 0 second, and the valve opening signal time, that is, the injection pulse width Ti is increased from that time, the valve body is increased for the increased time. The time for stopping at the position of the target lift becomes longer, and the valve closing completion timing increases as the rest time increases to increase the injection amount, so that the injection pulse width Ti and the fuel injection amount q are linearly related. It is recommended that

Further, when the fuel pressure supplied to the fuel injection device changes, the peak current value I _peak necessary for the valve body 114 to reach the target lift and the holding current value Ih that can hold the valve body 114 in the open state. Changes. When the fuel pressure increases, in a state where the valve body 114 is closed, a force obtained by multiplying the pressure receiving area of the seat diameter and the fuel pressure acts on the valve body. Therefore, it is necessary for the valve body 114 to start opening the valve. Increases the suction power. Further, when the valve body 114 starts to be displaced, the flow velocity of the fuel flowing through the fuel seat portion of the valve body 114 becomes faster, and the pressure rapidly decreases due to the influence of the static pressure drop based on Bernoulli's theorem. The pressure difference between the piping side and the tip of 114 increases, and the differential pressure acting on the valve body 114 increases. The required peak current value I _peak , drive voltage cutoff time Tc, and holding current value Ih may be adjusted according to the increase in the differential pressure. When the driving current holding current value Ih is kept constant under a wide range of fuel pressure conditions with different engine loads, the mover 102 is configured so that the valve element 114 can be held in the open state at a high fuel pressure. Therefore, it is necessary to set a high holding current value Ih that can generate a magnetic attractive force acting on the. When the fuel injection device 640 is driven at a low fuel pressure using a high holding current value Ih, when the injection pulse width Ti is stopped, the magnetic attractive force generated in the mover 102 becomes large, and the valve closing delay time Increases and the injection amount also increases. Therefore, the ECU 120 is configured to send a command signal to the drive circuit 121, and an appropriate holding current value Ih according to the fuel pressure is determined using a signal from a pressure sensor attached to the fuel pipe upstream of the fuel injection device. It is good to set.

Further, the individual variation of the fuel injection device in each cylinder also changes the holding current value Ih necessary for holding the valve element 114 in the valve open state due to the variation in the load of the spring 110, similarly to the change in the fuel pressure. In an individual with a large spring, the magnetic attraction force required to hold the valve body 114 in the valve open state becomes large, so the holding current value Ih needs to be set large. The load of the spring 110 is adjusted in the process of adjusting the injection amount of the fuel injection device 640. Therefore, since there is a strong correlation between the valve opening delay time, the valve closing delay time, and the load of the spring 110, the load of the spring 110 can be estimated from the opening / closing valve delay time.

It is effective to adjust the current waveform according to the fuel pressure in addition to the adjustment of the peak current value I _peak , the boost voltage marking time Tp, and the drive voltage cutoff time Tc for reducing the individual variation of the fuel injection device 640 of each cylinder. It is. As the fuel pressure increases, the differential pressure acting on the valve body 114 increases, so the timing at which the valve body 114 decelerates after the peak current value I _peak is cut off, and the valve body 114 reaches the target lift position. The bounce from will be smaller. Accordingly, by increasing the peak current value I _peak according to the increase in fuel pressure, the movable element 102 and the fixed core are secured while ensuring the peak current value I _peak necessary for the valve body 114 to reach the target lift. The collision speed 107 can also be reduced, the non-linearity of the injection quantity characteristic can be reduced, and the injection quantity variation can be reduced. Further, when the peak current value I _peak is increased, the drive voltage cutoff time T3 is delayed, and the drive voltage cutoff time Tc is also delayed in conjunction with it. The boosted voltage cut-off time Tc is preferably configured to become shorter as the fuel pressure increases. With such a configuration, when the differential pressure acting on the valve body 114 increases as the fuel pressure increases, the collision speed between the mover 102 and the fixed core 107 decreases, and therefore the timing required for deceleration also decreases. Therefore, it is possible to set an appropriate deceleration timing. Since the fuel pressure and the differential pressure acting on the valve body have a linear relationship, a correction coefficient for determining the peak current value I _peak and the holding current value Ih is given to the ECU or EDU in advance according to the fuel pressure. It is good to keep. Further, the current used can be reduced by adjusting the peak current value I _peak and the holding current value Ih described above for each fuel injection device 640 of each cylinder and for each fuel pressure supplied to the fuel injection device 640. Therefore, the heat generation of the solenoid 105 of the fuel injection device and the heat generation of the ECU can be reduced, and the energy consumption can be reduced. In addition, since the time during which the boost voltage VH is applied is reduced, the load on the boost circuit can be reduced, and the boost voltage VH at the time when the next injection pulse width is required in multistage injection can be kept constant. Therefore, it is possible to accurately control the injection amount.

Next, FIG. 19 shows an operation for using a region where the valve body 114 does not reach the target lift (referred to as an intermediate lift region) by the operation procedure of this method. In this operation, in order to realize an injection amount that is smaller than the minimum injection amount when the target lift is reached, the peak current value I _peak is lowered from the standard set value in accordance with the reduction in the injection amount. In order to reduce the injection amount. That is, when realizing an injection amount smaller than the injection amount by the operation shown in FIG. 18, the valve opening signal time Ti is not changed, but the set value itself of the peak current value I _peak that determines the time to apply the boosted voltage itself To change. Alternatively, the set value itself of the boost voltage application Tp is changed. As shown in FIG. 18, by setting to a set value Ip ′ smaller than the standard peak current value I _peak , application of the boost voltage VH is stopped at time T3 when the current flowing through the solenoid 105 reaches Ip ′. As a result, the boosted voltage VH is applied in the reverse direction, and the current flowing through the solenoid 105 rapidly decreases, thereby reducing the magnetic attractive force. As a result, the valve body 114 that has started the lift operation at time T2 reverses to negative acceleration at the time T4, parabolically moves to a height that does not reach the target lift, and closes at time T12. In this operation, since the valve body 114 does not reach the target lift, the displacement amount of the valve body 114 is not defined by the mechanism, and individual variations in the injection amount are likely to occur. Therefore, by measuring the valve closing completion timing T12, the ECU 120 or the EDU 121 checks whether or not it coincides with the valve closing completion timing for realizing the required injection amount. At the time of injection, it is possible to increase the accuracy of the actual injection amount with respect to the required injection amount by adjusting the peak current set value Ip ′ by increasing or decreasing it. Similarly, in the case of the method for setting the boost voltage application time, the valve closing completion timing T12 is measured, and the boost voltage application time is adjusted to match the valve closing completion timing for realizing the required injection amount. Thus, the accuracy of the actual injection amount with respect to the required injection amount can be increased.

21 to 25 show a fifth example of a method for controlling the fuel injection device using the present invention.

FIG. 21 shows a valve opening that is an inter-terminal voltage and a drive current when the valve body 114 reaches the target lift and is driven in the technique according to the fifth embodiment of the present invention, and the acting force acting on the valve body 114. It is the figure which showed the relationship between the force of a direction (valve opening force), the force (valve closing) of a valve closing direction, the displacement amount of the valve body 114, and time. The horizontal axes of the four graphs shown in the figure are all time, and the places with the same vertical position indicate the same time. In the drawing, the top diagram shows the voltage across the terminals of the solenoid 105 of the fuel injection device, and the second diagram shows the drive current flowing through the solenoid 105 of the fuel injection device 650. The third diagram shows the valve body driving force applied to the valve body 114 of the fuel injection device 640, and the fourth diagram shows the displacement amount of the valve body 114 in the lift direction. FIG. 22 is a diagram showing the relationship among the terminal voltage, the drive current, the valve body driving force, and the valve body variable, which are the operations of the minimum amount injection, when the injection amount is narrowed by extending the operation of FIG. .

In FIG. 21, the injection pulse width Ti is supplied at time T1, and the valve opening signal starts. At this timing, the boosted voltage VH is applied to the solenoid 105 of the fuel injection device. By applying this voltage, a current starts to flow through the solenoid 105, but a magnetic flux is generated inside the magnetic circuit along with the current, and a back electromotive force is generated due to the increase in the magnetic flux. Therefore, the current flowing through the solenoid 105 rises stepwise. It is a characteristic that increases with time. When current starts to flow through the solenoid 105, a magnetic flux is generated with a slight time delay, and a magnetic attractive force is generated by the magnetic flux. The magnetic attractive force is a force in the direction of opening the valve, but the valve body 114 is also applied with a force in the direction of closing the valve, so the moment when the force in the valve opening direction exceeds the force in the valve closing direction (= time T2 ) Begins to lift the valve body 114. The force in the valve closing direction includes spring force and fluid force. Since the spring 110 used here has a much larger deformation amount when the spring 110 is set than the displacement amount of the valve body 114, the spring load at the time of opening and closing is almost the same. The force in the valve closing direction is generated by the fluid force mainly due to the fact that the pressure on the downstream side of the seat portion where the valve body 114 is seated by the valve closing is lower than the fuel pressure on the upstream side. When the valve body 114 starts to lift and a flow is generated in the seat portion, the static pressure of the fuel is converted into a dynamic pressure, so that the static pressure in a part of the region decreases and the fluid force changes. Further, as the valve body 114 is operated, the fluid force acting on the valve body 114 is also changed by the pressure change generated by the flow resistance in the space where the fluid is removed or flows in. Therefore, although the force in the valve closing direction, which is the sum of the spring force and the fluid force, is not exactly constant, the change is not so large, and is shown by a constant line in the figure.

The time for applying the boosted voltage VH to the solenoid 105 is a method of stopping when the set time Tp is reached, and when the current flowing through the solenoid 105 reaches the peak current value I _peak set in the CPU 601 or IC 602 in advance. There is a way to abort. That is, when the boost voltage application time Tp is set, the peak current value I _peak is dependently determined, and when the peak current value I _peak is set, the boost voltage application time Tp is dependently determined thereby. The boost voltage application time Tp or the peak current value I _peak is set according to the characteristics of the fuel injection device and the fuel pressure, so that even if there are changes in environmental conditions or individual variations in the fuel injection device, It becomes possible to reduce the variation in operation of the fuel injection device. For example, when the peak current value I _peak is fixed, even if the current value profile fluctuates due to individual variations in the boosted boost voltage VH, heat generation of the solenoid 105, or the like, Although the valve opening completion timing varies, this effect is a change in which the displacement of the valve body moves in parallel, and can be corrected using information on the valve opening delay time. Next, when the application of the boosted voltage VH is stopped at time T3, a voltage in the opposite direction is automatically applied. The current flowing through the solenoid 105 ends the application of the positive voltage, and the current is going to disappear. However, when the current decreases, the magnetic flux inside the magnetic circuit decreases, and when the magnetic flux decreases, the change is canceled. An induced electromotive force is generated in the direction. Due to this induced electromotive force, a positive current flows through the solenoid 105, so that the current does not immediately become zero immediately after time T3 but gradually decreases. When the boosted voltage in the reverse direction is applied to the solenoid 105, the rate of decrease in the forward current increases. When the current flowing through the solenoid 105 decreases, the magnetic flux decreases and the magnetic attractive force decreases, thereby decreasing the force in the valve opening direction. When the force in the valve opening direction exceeds the force in the valve closing direction, the movement of the valve body 114 is accelerated in the lift direction, but at the moment T4 when the valve opening force and the valve closing force are balanced. In addition, the valve body 114 is accelerated at the speed at that time. Even after the time T4, the application of the boosted voltage VH in the negative direction is continued, and the current flowing through the solenoid 105 is continuously decreased, so that the magnetic attractive force is reduced, the valve closing force exceeds the valve opening force, and the valve body 114 Moves to slow down. While the movement of the valve body 114 is decelerated, the application of the reverse current to the solenoid 105 is terminated at time T5 while the valve body 114 is moving in the lift direction, and at the same time, the battery voltage VB is applied to the solenoid 105. The time Tc from when the reverse voltage is applied to the solenoid 105 until the end is set according to the characteristics of the fuel injection device and the fuel pressure, so that even if there is a change in environmental conditions or individual variations of the fuel injection device It becomes possible to reduce operation variation.

After time T5, by applying the battery voltage VB that is lower than the boosted voltage VH, the current flowing through the solenoid 105 rises slightly moderately. As the current increases, the magnetic attractive force also increases gradually. When the magnetic attractive force again exceeds the valve closing force at time T6, the movement of the valve body 114 is switched from deceleration to acceleration.

While the battery voltage VB is being applied, the current flowing through the solenoid 105 is monitored. When the set holding current value Ih is reached, the voltage is temporarily turned off, and after the set minute time, the battery voltage VB is Continue to apply. By continuing such an operation, the current value flowing through the solenoid 105 can be maintained near the set holding current value Ih, and the magnetic attractive force can be controlled.

Further, at the time T7, the valve body 114 reaches the target lift position. The time from the time T1 when the valve opening signal is started to the time T7 when the full lift is completed is the valve opening completion delay time Ta. As the structure of the fuel injection device, the part that receives the magnetic attraction force and the valve body 114 are separated, the former is the movable element 102, the movable element 102 is configured to transmit only the force in the valve opening direction to the valve body 114, and is movable. If there is a play in which the valve element 114 side can move further even when the child 102 reaches the target lift position, after both the mover 102 and the valve element 114 reach the target lift position, the mover 102 is fixed to the fixed core 107. However, only the valve body 114 continues to rise, and overshoot occurs in the movement of the valve body 114. Before and after this overshoot occurs, the injection amount control proportional to the valve opening signal time cannot be performed. Therefore, the smaller the overshoot, the better. Therefore, the speed of the valve body 114 at time T7 when the valve body 114 is fully lifted is as small as possible. The current flowing through the solenoid 105 is preferably adjusted so that As an adjustment method at that time, the set values of the boost voltage application time Tp or peak current I _peak , the reverse voltage application time Tc, and the valve body 114 lift holding current Ih are set to the characteristics of the individual fuel injection devices 640 and the fuel pressure. It should be changed accordingly.

After the overshoot has settled, the magnetic attraction force applied to the mover 102 remains stronger than the closing force applied to the valve body 114, but the mover 102 comes into contact with the fixed core 107 at the target lift position. The movement stops, and the valve body 114 also remains stationary at the target lift position.

When the stop time of the injection pulse width Ti is reached at time T9, when the application of the battery voltage VB to the solenoid 105 is finished, the boosted voltage VH is automatically applied in the reverse direction. At time T9, the magnetic circuit around the solenoid 105 has a magnetic flux that has generated a magnetic attractive force. Therefore, an induced electromotive force is generated according to the rate of current decrease, and the current is only moderately after time T9. Will not decline. When the current drop is slow, the magnetic attraction force disappears slowly and the valve closing starts slowly. By applying a boosted voltage VH higher than the battery voltage VB in the reverse direction, the current disappearance is accelerated and the valve closing operation is performed. It's good to be early. Even after the current value supplied to the solenoid 105 becomes zero at time T10, the magnetic flux remains in the magnetic circuit due to the influence of the eddy current. Since the electromotive force is generated, the voltage between the terminals of the solenoid 105 also becomes a negative voltage. However, since the magnetic flux in the magnetic circuit is reduced, the eddy current is reduced and the rate at which the magnetic flux disappears is also reduced. The induced electromotive force is gradually reduced, and the voltage between the terminals of the solenoid 105 is also gradually lowered. Further, when the voltage measurement terminal is not the voltage between the terminals of the solenoid 105 but the potential difference between the ground potential (GND) side terminal of the solenoid 105 and the ground potential (GND) in the second embodiment, the voltage is positive. As the eddy current disappears, the voltage decreases.

The magnetic attraction force decreases due to a decrease in the current flowing through the solenoid 105, and when the magnetic attraction force falls below the valve closing force at time T11, the valve body 114 starts to move in the valve closing direction. As the positional relationship between the valve body 114 and the movable element 102, the displacement in the lift direction, that is, the positive direction, is the valve body 114 ≧ the movable element 102, and the valve body 114 may be above the movable element 102. The reverse is not the case. Similarly, even if the movable element 102 is lower than the valve element 114, the valve element 114 does not go below the movable element 102. Therefore, when the valve body 114 moves in the valve closing direction, the mover 102 always moves in the valve closing direction. When the valve body 114 is held at the target lift position, the mover 102 comes into contact with the fixed core 107 and is attracted to the suction surface of the contact end surface, and when the mover 102 leaves the mover 102, And the fuel must flow into the space between the fixed core 107. Since the magnetic attraction surface has only a small gap, the flow resistance of the fuel is large for the fuel to flow into the space, and the resistance increases as the mover 102 moves faster. When the flow resistance (referred to as squeeze force) increases, the pressure in the space decreases, and the fluid force on the surface in contact with the space decreases, so that the valve closing force due to the fluid force decreases. In general, the squeeze force is proportional to the speed of the mover 102 and inversely proportional to the cube of the distance between the mover 102 and the fixed core 107, so that the gap between the mover 102 and the fixed core 107 increases. Squeeze power drops rapidly. Although the exact description of the squeeze force is not shown in the diagram of the valve body driving force in FIG. 21, there is an element that slows down the valve closing operation due to the fluid force. Remains a gradual valve closing operation. As the valve body 114 moves away from the target lift position, the magnetic attraction force decreases and the squeeze force also decreases, so that the valve closing force exceeds the valve opening force. When the valve element 114 reaches the valve closing position at T12, the valve closing operation is completed. Therefore, the difference between times T12 and T9 is the valve closing completion delay time Tb.

The valve closing completion time Tb changes due to individual variations caused by the dimensional tolerance of the fuel injection device, changes in fuel pressure, changes in environmental conditions such as temperature, changes in operating characteristics due to deterioration, and the like. When this time changes, the injection amount changes. Therefore, if the injection amount needs to be accurate, the valve closing completion delay time Tb is measured, and the opening amount is opened at the next injection by the amount deviating from the standard valve closing completion delay time. By adjusting the valve signal time by increasing or decreasing it, it is possible to suppress variations in the injection amount and increase the accuracy of the injection amount. In addition, when the valve closing completion delay time Tb is large, the holding current Ih is lowered to reduce the magnetic attraction force when maintaining at full lift, thereby reducing the difference between the valve opening force and the valve closing force. It is also possible to adjust the injection amount to be small by advancing time T11 which is a point where the force crosses the valve closing force. Conversely, when the detected delay time Tb is smaller than the standard valve closing completion delay time, the holding current Ih can be increased to adjust the standard valve closing completion delay time.

When operating the fuel injection device according to the above procedure, the valve opening signal time Ti may be changed accordingly in order to widely control the amount of fuel injected by one injection. When the valve opening signal time Ti is increased, only the time during which the valve body 114 is stationary at the full lift position is increased in proportion thereto, and the operations before and after that are the same. Therefore, if the injection amount per unit time when the vehicle is stationary with a full lift is multiplied by the time during which the valve opening time is increased, the increasing injection amount is determined. From this relationship, the valve opening signal time necessary for realizing the required injection amount can be calculated backward, and therefore the injection amount can be controlled by the valve opening signal time Ti.

The operation of the minimum amount injection when the injection amount is narrowed down by extending the above operation is shown in FIG. In showing FIG. 22, variables having the same meaning as in FIG. 21 have the same variable names.

In FIG. 22, the valve opening signal time Ti ends immediately after time T7 when the full lift of the valve body 114 is completed, and the valve closing operation starts. Therefore, the valve opening operation and the valve closing operation are exactly the same as in the case of FIG. 20, and the procedure for operating the valve body 114 so as to minimize only the time during which the valve body 114 is stationary at the target lift position is the movement of FIG. . Further, in order to minimize the time during which the valve body 114 is stationary at the target lift position, it is preferable to minimize the overshoot of the valve body 114. For that purpose, the valve opening completion time Ta is measured and the fuel injection is performed. It is preferable to adjust set values such as the boost voltage application time Tp or the peak current I _peak , the reverse voltage application time Tc, and the holding current Ih after grasping the variation of this time for each device 640.

FIG. 23 shows an operation method for realizing an injection amount smaller than the amount injected by the operation of FIG. In FIG. 23, the process up to applying the boosted voltage VH to the solenoid 105 and then applying the boosted voltage VH in the negative direction is the same as in FIGS. 21 and 22, and the subsequent battery voltage VB is applied. Only the time for passing the holding current Ih is shortened. Since the valve body 114 has not yet reached the target lift at time T9 when the injection pulse width Ti is stopped and the holding current Ih is stopped, the valve opening operation continues even after time T9. However, since the current supplied to the solenoid 105 at time T10 disappears, the magnetic attractive force decreases, and accordingly, the difference between the valve closing force and the valve opening force widens, and the force to push back the valve body 114 increases. Go. During these processes, at time T9, the valve body 114 was moving in the valve opening direction, but the speed decreased, the speed became negative, and the valve body 114 moved in the valve closing direction. It becomes like this. As a result, the valve closing is completed at time T12, and the operation ends without reaching the target lift even once during the operation of the valve body 114.

By the operation of this method, it is possible to control a very small injection amount because the time T5 at which the holding current operation starts is significant from the valve opening completion time T7 when the valve body 114 reaches the target lift. This is because there is a long time difference. That is, if there is a time difference between the holding current start time T5 and the valve opening completion time T7, it becomes possible to bring the holding current end time T9 before the valve opening completion time T7. Therefore, it becomes possible to take a valve opening signal time shorter than the injection pulse width Ti of the minimum injection amount operation in the case of full lift as shown in FIG. 22, and even in that case, the valve opening signal time Ti is proportional to the shortening. It becomes possible to reduce the injection amount. At that time, the ratio of the increase amount of the injection amount to the increase amount of the valve opening signal time when reaching the target lift, and the ratio of the increase amount of the injection amount to the increase amount of the valve opening signal time when not reaching the target lift are In such a case, if the valve opening signal time is determined by back calculating the valve opening signal time according to the characteristics, the required injection amount can be realized by the control. As a result, it is possible to control to inject an injection amount that is even smaller than the minimum injection amount when the target lift is reached.

In the operation that does not reach the target lift as the movement of the valve body 114, there is an adjustment parameter that can be controlled only in the first half of the operation, and control cannot be added in the second half of the operation. For this reason, the injection amount is likely to vary even under the same valve opening signal time due to the influence of variations in characteristics among the fuel injection devices of each cylinder and changes in operating characteristics due to changes in environmental conditions, deterioration, and the like. At that time, if the valve opening completion delay time or the valve closing completion delay time is measured so that it can be grasped when the characteristics change, the controllable adjustment parameters in the first half of the valve body operation can be adjusted. By changing it, the accuracy of the actual injection amount with respect to the required injection amount can be maintained even with a very small injection amount.

FIG. 24 collectively shows a series of operations according to the present method. Since the time Tp for applying the boosted voltage VH and the time Tc for applying the boosted voltage VH in the negative direction are determined by the result of measuring the operation of the valve body 114, they are constant regardless of the required injection amount. Only the maintenance time is changed according to the required injection amount. For this reason, when the valve opening signal time is Ti_1, the valve closing completion time becomes T12_1, and when the valve opening signal time is Ti_2, the valve closing completion time changes to T12_2 in the same manner. When the time is Ti_4, the valve closing completion time is T12_4. Since the injection amount to be injected from the fuel injection device 640 is determined according to the area of the curve drawn by the time change of the displacement amount of the valve body 114, a very small amount of injection amount is changed from a very small injection amount by the change of the valve opening signal time. The injection can be controlled uniformly.

Next, FIG. 25 shows the relationship between the injection pulse width Ti and the fuel injection amount q when the fuel injection device is driven by the control method of the sixth embodiment. In FIG. 25, the injection amount characteristic by the current waveform of the fifth embodiment is shown by a solid line, and the injection amount characteristic by the current interruption waveform of FIG. 17 described in the control method in the fourth embodiment is shown by a one-dot chain line and a conventional waveform. The injection amount characteristic is indicated by a broken line. 25, the fuel injection amount q under the same injection pulse width Ti is smaller than the injection amount characteristic of the cutoff waveform described in the fifth embodiment, and the injection amount in the linear region is on the lower side. It has shifted characteristics. In the cutoff waveform, the minimum injection amount under the condition that the valve body 114 reaches the target lift is 2502, whereas in the waveform of the sixth embodiment, the minimum injection amount is 2501, which is the same as in the fourth embodiment. Compared to the control method, the minimum injection amount under the condition that the valve body 114 reaches the target lift position becomes larger. However, by controlling the valve body 114 to reach the target lift with the holding current value Ih by lowering the peak current value I _peak than the control method according to the fifth embodiment, the injection pulse width in the intermediate lift region Since the increase q of the fuel injection amount with respect to the increase of the valve body 114 and the slope of the increase of the fuel injection amount q with respect to the increase of the injection pulse width in the region after the valve body 114 reaches the target lift can be made as close as possible. The fuel injection amount q can be uniformly controlled by increasing or decreasing the injection pulse width Ti from the region. With such a configuration, with respect to individual variations of the fuel injection device 640 of each cylinder, the set values of the peak current value I _peak or the boost voltage marking time Tp, the boost voltage cutoff time Tc, and the holding current value Ih are opened. By correcting based on the detection information of the valve closing timing, the individual variation occurring in the injection amount characteristic is only the intercept q _b of the ideal straight line 2503 subtracted from the region where the injection pulse width Ti and the fuel injection amount q are substantially linear. Therefore, by correcting the injection pulse width Ti for each individual, the injection amount required by the ECU or the drive device can be accurately controlled. In addition, after adjusting the set value of the current waveform, correction of the intercept q _b generated in the injection amount characteristic is performed only by the injection pulse width, so that the opening / closing completion timing is detected for each intake / exhaust stroke. Since it is not necessary, the calculation load on the CPU 601 or the IC 602 can be reduced, and the number of data points stored in the CPU 601 or the IC 602 can be reduced, so that the memory capacity for storing the detection information of the opening / closing timing is reduced. It comes out. In addition, since the peak current value I _peak is set smaller than in the fifth embodiment, the dead zone Tn generated in the injection amount characteristic in the fifth embodiment is reduced to the dead zone Tn1 in the control method in the fifth embodiment. Since the region where the relationship between the injection amount pulse width Ti and the fuel injection amount q is linear can be expanded, there is an advantage that the injection amount can be easily controlled.

The movement when the valve body 114 is operated by the method in the sixth embodiment of the present invention will be described with reference to FIGS. 26, 27, and 28. FIG. In FIG. 26, the injection pulse width Ti is applied at time T1, the valve opening signal is turned ON, and the application of the boost voltage VH is started. As a result, the current flowing through the solenoid 105 rises. In the method of the sixth embodiment of the present invention, a lower peak current value I _peak is set than in the method of the fifth embodiment, and when that current value is reached, Once the application of the boost voltage VH is discontinued. In this method, when the current value reaches the peak current value I _peak and the voltage application is stopped, the current due to the induced electromotive force of the solenoid 105 is not rapidly extinguished so that the boosted voltage VH in the negative direction is not applied. Switch operation to. After the application of the boosted voltage VH is switched, switching is performed so that the boosted voltage VH is applied again when the set time has elapsed. By operating in this way, the current flowing through the solenoid 105 can be maintained near the set peak current value I _peak . When such an operation is performed, the magnetic attraction force can be maintained at a lower magnetic attraction force than the method in the fifth embodiment by maintaining the current at the set value of the lower peak current value I _peak. Is possible.

Thereafter, at time T3, which is the time when the set time Tp of the boost voltage application time is reached, the voltage application is terminated, and the switch is operated so that the negative boost voltage VH is automatically applied. As a result, the magnetic attractive force decreases, and the magnetic attractive force crosses the valve closing force at time T4, so that negative acceleration is applied to the movement of the valve body 114, and time T5 when the drive voltage cutoff time Tc is reached. Immediately thereafter, adjustment is made so that the valve body 114 comes at the full lift time T7. Also, depending on the specifications of the fuel injection device 640, the magnetic attractive force may not cross the valve closing force at time T4, but compared with the case where the valve element reaches the target lift at a high current value, The acceleration of the valve body 114 can be reduced.

In this method, the magnetic attraction force is maintained at a low force by setting the current to be passed through the solenoid 105 to be low so that the applied voltage is cut off while the boosted voltage VH is being applied. become. Thereby, the time from the time T3 when the application of the boost voltage VH is stopped to the time T4 when the magnetic attractive force crosses the valve closing force can be shortened. Thereby, the time until the movement of the valve body 114 shifts from the acceleration state to the deceleration state is shortened, and thereafter, the time for decelerating the movement of the valve body 114 can be shortened. In that case, the amount of deceleration applied to the valve body 114 becomes too large or insufficient, and it is possible to reduce the amount of overshoot that occurs after the valve body 114 reaches the target lift position. It becomes easy to do.

In addition, due to the effect that the time from the time T3 when the application of the voltage VH is stopped to the time T4 when the magnetic attractive force crosses the valve closing force can be shortened, the movement of the valve body 114 changes from the acceleration state to the deceleration state. Since the time until the transition is shortened and the collision speed between the movable element 102 and the fixed core 107 can be reduced, it is possible to suppress the valve body bound 117 that occurs after the valve body 114 reaches the target lift.

After time T5, the battery voltage VB is applied, the current flowing through the solenoid 105 is maintained near Ih, and the valve body 114 is stopped at the target lift position. When the valve opening signal time Ti is reached, the valve closing operation is performed in the same manner as the conventional methods.

FIG. 27 shows an operation when the minimum injection amount is performed after the valve body 114 is lifted by the target according to the method of the sixth embodiment. At the time T5, when the battery voltage VB is applied, the injection pulse width Ti of the valve opening signal time is cut off, and the valve body 114 performs the valve closing operation. Since the timing at which the valve body 114 reaches the target lift is adjusted to occur immediately after the time T5, the valve closing operation continuously occurs according to the valve closing operation that occurs simultaneously with the time T5. At this time, since the magnetic attractive force when the boosted voltage is applied is adjusted to be low, the time for the force applied to the valve body 114 to switch from the acceleration direction to the negative acceleration is shortened. It is possible to improve the temporal accuracy during operation. When this accuracy increases, the minimum injection amount after the valve body 114 reaches the target lift can be sufficiently reduced, and the injection amount when the target lift is not reached is continuously increased. This enables continuous injection amount control. Therefore, since the relationship between the injection pulse width and the injection amount always has a positive correlation in the region where the target lift is reached from the region where the target lift is not reached, the control logic when the required injection amount continuously increases There is an advantage that can be simplified.

FIG. 28 shows an operation method when the full lift is not performed by the method of the seventh embodiment. 26 to 27, the injection amount is controlled by the valve opening signal time Ti. However, when the injection amount is further reduced from FIG. 27, the injection pulse width Ti that is the valve opening signal time is not changed, but the boost voltage is changed. The application time Tp is changed. When the boost voltage application time Tp is changed, the time for applying the force in the valve opening direction to the valve body 114 by the magnetic attraction force is shortened, and accordingly, the release of the valve body 114 after the application of the boost voltage VH is finished. The physical movement is also reduced. Therefore, the valve body 114 performs an operation that does not reach the target lift position, and the valve closing is completed at time T12. As in the conventional methods, the operation of the valve body 114 that does not reach the target lift position is likely to vary widely among the individual fuel injection devices 640. Therefore, by measuring the valve closing completion timing T12 for each fuel injection device 640 of each cylinder, the deviation from the operation for realizing the required injection amount is grasped, and the boosted voltage application time Tp is adjusted, the required injection amount It is possible to improve the accuracy of the actual injection amount with respect to.

The movement when the valve body 114 is operated by the method of the seventh embodiment of the present invention will be described with reference to FIGS. 29, 30, and 31. FIG. In FIG. 29, application of the battery voltage VB is started at time T0 prior to time T1. As a result, current starts to flow through the solenoid 105, but when the current reaches the precharge current value Ic, the application of the battery voltage VB is cut off, and control is performed so that no more current flows. At this time, the switch operation is combined so that the voltage in the negative direction is not applied even if the voltage application is interrupted. After the current has reached the precharge current value Ic, the voltage is turned off, and then the battery voltage VB is repeatedly applied after a predetermined time, so that the current near the set precharge current value Ic is maintained. To do. The time for supplying the precharge current Ic is determined in advance as the precharge time Td, and when this time has passed, the valve opening signal is turned on and the injection pulse width Ti is supplied. Further, when the precharge current value Ic is caused to flow through the solenoid 105, a magnetic flux is formed in advance in the magnetic circuit and a magnetic attractive force is generated. However, the magnetic attractive force is pre-prevented so as not to exceed the valve closing force. The charge current Ic may be set. Further, when the fuel pressure increases, the valve closing force due to the fuel pressure applied to the valve body 114 increases, and the magnetic attractive force necessary for the valve body 114 to start opening increases, so the fuel injection device detected by the pressure sensor The precharge current value Ic may be set for each fuel pressure supplied to the 640. With such a configuration, an appropriate precharge current value Ic can be set according to a change in fuel pressure. In addition, the magnetic attraction force required for the valve body 114 to start opening differs depending on the dimensional tolerance of the fuel injection device 640, particularly the individual variation in the load of the spring 110. When the load of the spring 110 is large, the magnetic attractive force necessary for starting the valve opening becomes large, so that the precharge current Ic is increased. On the other hand, when the load of the spring 110 is small, the magnetic attractive force necessary for starting the valve opening is increased. Therefore, it is preferable to reduce the precharge current Ic. By using the above configuration, an appropriate precharge current Ic can be set even when the fuel pressure supplied to the fuel injection device 640 changes or when the load of the spring 110 of the fuel injection device is different. Therefore, the injection amount can be controlled with high accuracy.

When the valve opening signal, that is, the injection pulse width Ti is turned on at time T1, the same operation procedure as that of the control method of the fifth embodiment shown in FIG. 21 is performed thereafter. However, since the application of the boost voltage VH starts in a state where the magnetic attraction force is generated to some extent by the precharge current value Ic, the timing T2 when the magnetic attraction force exceeds the valve closing force is advanced, and the valve opening operation is started from the application of the boost voltage VH. Time to start is reduced. When this time is shortened, it is possible to reduce the variation in the valve opening start time due to individual variations in the fuel injection device. In general, when a current is supplied to the solenoid 105, the magnetization of the magnetic material constituting the magnetic circuit progresses from the vicinity of the inside of the solenoid 105 toward the outer peripheral side due to the influence of the eddy current. On the other hand, when the current supply to the coil is stopped, the magnet is demagnetized from the inner peripheral side of the fixed core 107 far from the solenoid 105. By generating a magnetic flux in the magnetic circuit in advance by the precharge current Ic, the counter electromotive force generated by the eddy current can be reduced as compared with the case where the current is supplied to the solenoid 105 from the state where the magnetic flux is not generated. Therefore, the slope of the rise of the current value supplied to the solenoid 105 can be increased, and the rise of the magnetic attractive force can be accelerated. Due to this effect, the magnetic attractive force required for the valve body 114 to reach the target lift after applying the boosted voltage VH can be secured at an early timing compared to the case where there is no precharge current Ic. The current value I _peak can be set smaller than in the case of the fifth embodiment, and the power consumption determined in proportion to the square of the current value can be suppressed.

Further, after the open-starting at time T2, at time T3 the current flowing through the solenoid 105 reaches a peak current I _peak, abort the application of boosted voltage VH, thereby being applied automatically to the boost voltage is reversed Become so. When the reverse voltage is applied, the current flowing through the solenoid 105 rapidly decreases, and the magnetic attractive force also decreases accordingly. When the magnetic attractive force crosses the valve closing force at time T4, the movement of the valve body 114 moves to the lift method. While continuing to lift from an accelerating movement, the speed changes to a state of deceleration. The time Tc during which the drive voltage is cut off is determined in advance, and the application of the battery voltage VB is started at the time T5 when that time is reached. As a result, the magnetic attractive force starts to increase again, and the movement of the valve body 114 in the lift direction is maintained. While the battery voltage VB is applied, switching is performed so that the current is maintained at the holding current Ih. By performing this operation, the valve body 114 reaches the target lift at time T7, stops with a slight overshoot, and then stops at the target lift position. When the stop time of the injection pulse width Ti is reached, the boosted voltage VH is applied in the negative direction, the current flowing through the solenoid 105 is rapidly reduced, thereby reducing the magnetic attractive force, and the magnetic attractive force is closed at time T11. When the valve force is crossed, the valve closing operation is started, and the valve closing operation is completed at time T12. In general, when the valve body 114 is stationary, the force by the fuel pressure, which is a part of the valve closing force, is determined by a value obtained by multiplying the seat diameter area of the valve body 114 and the fuel pressure. On the other hand, when the valve body 114 starts to lift, fuel begins to flow to the seat portion of the valve body 114. However, under the condition that the lift amount of the valve body 114 is small, the flow passage cross-sectional area of the seat portion is small, and thus flows through the seat portion. The flow velocity of the fuel increases, and the pressure in the vicinity of the valve body 114 seat portion decreases due to the influence of a decrease in static pressure based on Bernoulli's theorem. At this time, the differential pressure acting on the valve body is a value obtained by subtracting the pressure at the top of the valve body 114 from the pressure at the tip of the valve body 114 and integrating the pressure receiving area in the radial direction. Therefore, when the pressure at the tip of the valve body 114 is low, the differential pressure acting on the valve body 114 increases, and the differential pressure acting on the valve body 114 increases compared to the closed state. Further, as the displacement amount of the valve body 114 increases, the flow passage cross-sectional area of the seat portion also increases, so the flow rate of the fuel flowing through the seat portion becomes slow, and the influence of the decrease in static pressure is reduced. The differential pressure acting on the body 114 decreases. In the fuel injection device 640, the magnetic attraction force, which is the valve opening force, quickly exceeds the maximum differential pressure acting on the valve body 114, so that a stable valve opening operation is possible even at high fuel pressure, and the injection amount is also controlled. It becomes easy. Since the rise of the magnetic attractive force is accelerated by the precharge current value Ic, the timing of overcoming the maximum value of the differential pressure can be advanced, so the time until the valve body 114 decelerates after reaching the peak current value _Ipeak Therefore, the collision speed between the movable element 102 and the fixed core 107 can be reduced, and the non-linearity of the injection amount characteristic caused by the valve body bounding due to the collision between the movable element 102 and the fixed core 107 can be improved. This makes it easy to control the injection amount at the timing when the valve body 114 reaches the target lift.

When the precharge current value Ic, which is a feature of this method, is not supplied, there is some variation in the valve opening start time due to individual variations in the fuel injection device 640, but the precharge current value Ic must be supplied. Thus, the absolute valve opening delay time is shortened, so that the variation in the injection amount is relatively reduced. When there is a variation in the valve opening delay time, it is necessary to adjust the set value I _peak of the peak current or the boost voltage application time Tp accordingly, but the variation is reduced by supplying the precharge current value Ic. Therefore, the adjustment range can be small, and the accuracy of the control operation can be increased accordingly, and the control accuracy of the injection amount can be improved. When the operation at the time of starting the valve opening is stabilized for each fuel injection device 640 of each cylinder, the operation of the valve body 114 when the valve body 114 reaches the target lift becomes stable, thereby reducing the overshoot. It becomes possible to improve the accuracy of the injection amount control.

FIG. 30 shows the operation of the minimum injection amount during the target lift of the valve body 114 while being controlled by the method in the seventh embodiment. This operation is most susceptible to overshoot, and when valve closing operation is started at time T9 immediately after the valve body 114 reaches the target lift, if the overshoot is large, it can be immediately switched to the valve closing operation. Therefore, the injection amount corresponding to the valve opening signal time Ti is not reached. When the overshoot is reduced by precharging, after entering the valve closing procedure at time T9, the operation becomes the same as when the valve closing procedure is entered from the state of being stationary at the target lift, and the valve opening signal time Ti is changed as shown in FIG. The injection amount is reduced in proportion to being shorter than the first case.

FIG. 31 is an operation for controllably realizing an injection amount smaller than the minimum injection amount when the valve body 114 reaches the target lift, and the valve opening signal time Ti is further shortened in accordance with a decrease in the injection amount. The operation is shown. The operation during the period of supplying the first half precharge current value Ic is the same as that in FIGS. 29 and 30, and this case is the case where the injection pulse width Ti ends immediately after the current cutoff time Tc is reached. It becomes the operation method to reduce the. When a reverse voltage is applied at time T9 and the magnetic attraction force decreases, the valve element 114 performs a parabolic motion without full lift, and the valve closing operation is completed at time T12.

In this embodiment, the combination of the control method for supplying the precharge current value Ic and the method for reducing the injection amount by the control method of the fifth embodiment has been described, but in addition to this, the precharge current value Ic is supplied. It is also possible to combine the control method for controlling the injection amount with the fourth and sixth control methods.

The relationship among the voltage between terminals, the drive current, the drive force acting on the mover (referred to as the mover drive force), and the displacement of the valve body when the fuel injection device is driven using the control method according to the eighth embodiment of the present invention. As shown in FIG. Further, FIG. 33 shows the relationship between the voltage between the terminals after stopping the injection pulse width Ti, the drive current, the mover driving force, the displacement amount of the mover and the time after stopping the injection pulse.

32, the difference from the control method in the fourth embodiment of FIG. 21 is that an operation of applying a voltage at time T13 is added. When the application of the boosted voltage VH is started at time T13 and then the application of the boosted voltage VH is stopped when the set time Te is reached, a force in the valve opening direction is applied to the valve body 114, and the valve is closed until then. Deceleration is added to the movement of the valve body 114 that has accelerated in the valve direction. When the movement of the valve closing is decelerated, the speed at the moment when the valve body 114 contacts the valve seat 118 decreases. If the speed at which the valve body 114 collides with the valve seat 118 is too high, the valve body 114 may bounce and slightly open the valve body 114, thereby causing a slight injection. When reducing the minimum injection amount, it is better not to bounce the valve body 114. Therefore, when the back pulse can be applied to eliminate the bounce of the valve body 114, this reduces the minimum injection amount. Is possible.

Also, the back pulse is preferably applied so that the boosted voltage VH and the battery voltage VB can be switched. When the battery voltage VB is used for the application of the back pulse, the effect of reducing the collision speed between the valve body 114 and the valve seat 118 is smaller than when the boost voltage VH is used, but the boost voltage VH is not used. There are effects that the load can be reduced by the ON / OFF operation of the switching element of the booster circuit, the power consumption of the driving device can be reduced, and the heat generation of the solenoid 105 can be reduced.

The time of applying the back pulse must be effectively applied in accordance with the valve closing completion time T12. If the timing is too early, the valve closing completion time is extended and the injection amount is increased. If the application timing of the back pulse is late, the valve closing speed is not slowed down by the magnetic attractive force, and the valve closing is completed before the valve is decelerated. Therefore, when the valve closing completion timing is detected for each fuel injection device 640 of each cylinder and the individual variation of the valve closing completion delay time is grasped, the back pulse is sent at the optimum timing according to the individual fuel injection device 640 of each cylinder. It is possible to strike the valve body, and it is possible to realize the control that does not increase the valve closing completion time while reliably eliminating the bounce that occurs when the valve body 114 is seated. Further, by applying the back pulse using the detection information of the valve opening delay time of each cylinder, the valve closing collision speed when the individual valve body 114 and the valve seat 118 of the fuel injection device 640 collide can be reduced. It is possible to reduce a collision sound generated when the metals of the valve body 114 and the valve seat 118 come into contact with each other. Further, since the wear of the seat portion of the orifice cup 116 caused by the collision between the valve body 114 and the valve seat 117 can be reduced by reducing the valve closing collision speed, the seat portion is worn due to durability deterioration, and the valve body. 114 can suppress an increase in the amount of leakage of fuel in the closed state. By reducing the leakage of fuel due to durability deterioration, the fuel leaking in the engine cylinder becomes coarse droplets, making it difficult for the fuel to vaporize, deteriorating fuel consumption performance, CO (carbon monoxide), NOx (nitrogen oxidation) Degradation of exhaust performance due to an increase in the number of particles), PM (particulate matter), or PN (PM particle number concentration). Further, by reducing the fuel leakage, it is possible to reduce the unburned fuel present in the engine cylinder. Therefore, it is possible to reduce the injection amount variation at the next injection, and to perform accurate injection amount control. Further, by reducing the valve closing collision speed, it is possible to reduce the driving sound at the time of valve closing caused by the collision between the metal of the valve body 114 and the valve seat 118, so that the driving sound generated by the fuel injection device 640 can be reduced. This can reduce the engine noise. In addition, according to the present embodiment, together with the impact noise reduction effect at the time of closing the valve, by supplying the negative boost voltage VH after reaching the valve closing peak current _Ipeak , before reaching the target lift position. The effect of abruptly decelerating the valve body 114 can reduce the collision speed between the movable element 102 and the fixed core 107, and the synergistic effect with the effect of reducing the collision noise when the valve is opened greatly increases the driving sound of the fuel injection device 640. It can be reduced.

Next, FIG. 33 is used to show the relationship between the terminal voltage, the drive current, the mover driving force, the mover displacement amount and the time after the stop of the injection pulse width Ti after the injection pulse width Ti is stopped. In addition, the displacement amount of the mover 102 when no back pulse is supplied is indicated by a broken line in the displacement amount of the mover in FIG.

As shown in FIG. 33, when the injection pulse width Ti is stopped while the mover 102 is in contact with the fixed core 107, the boost voltage VH in the negative direction is applied from the second voltage source, and the drive current rises sharply. Go down. Thereafter, at time T11 when the valve opening force acting on the mover 102 is less than the valve closing force, the mover 102 leaves the fixed core 107 and starts the valve closing operation. Thereafter, using the information on the valve opening completion timing stored in the driving device for each fuel injection device 640 of each cylinder, the second voltage source at time T14 before the valve body 114 contacts the valve seat 118. To boost voltage VH. The time 15 at which the application of the boosted voltage VH for supplying the back pulse ends is such that the valve element 114 comes into contact with the valve seat 118 and before the time T17 when the displacement of the movable element 102 is minimized. It is good to set to. With this configuration, the movable element 102 continues to move even after the valve element 114 is closed, but after the valve element 114 is closed, the movable element 102 is in the downward movement period Tu during the downward movement. During this period, a magnetic attractive force exceeding the valve closing force can be appropriately applied, and the time T18 at which the movement of the mover 102 stops can be advanced. In addition, there is a method in which the application of the pack pulse is stopped during the period of applying the back pulse at the back pulse application time Te or at the time when the back pulse current value Ipd applied to the driving device is reached in advance. By determining the stop timing of the back pulse by the back pulse current value Ipd, even when the voltage value of the boost voltage VH fluctuates, energy necessary for stopping the movement of the mover 102 is supplied to the solenoid 105. Therefore, an appropriate current can be given to each fuel injection device 640 of each cylinder. Further, when the valve closing completion time T12 of the valve body 114 is reached, the valve closing force that has been applied to the mover through the valve body 114 until then is not received, so that the valve closing force that is applied to the mover 102 is reduced. Therefore, since the difference between the valve opening force and the valve closing force can be increased, the undershoot of the mover 102 can be suppressed. When the valve opening force exceeds the time T17 and acts on the mover 102, the back pulse current value Ipd is decreased or the back pulse current Ipd is decreased and the back pulse current Ipd is constant. The boosted voltage VH is preferably switched. At the time of multistage injection in which a plurality of injections are performed during one intake / exhaust stroke, the time until the second injection is performed can be reduced by the effect of advancing the time T18 at which the movement of the mover 102 is stopped by the back pulse. Therefore, the number of multistage injections can be increased. Further, in the engine, the period during which fuel can be injected may be limited due to the restriction of the piston position in the intake stroke / exhaust stroke. However, the effect of reducing the divided injection interval in the present embodiment is one intake stroke. If you want to change the split ratio between the first injection amount and the second injection amount when performing multi-stage injection, for example, when the split ratio between the first and second injections is significantly changed, for example, 8: 2. Therefore, it is possible to meet the demand for a complicated injection amount control method. Further, as described by the broken line of the mover displacement amount in FIG. 33, under the condition without back pulse, the collision speed between the valve body 114 and the valve seat 118 is large, so that the undershoot of the mover 102 after the valve closing becomes large. Since the movement duration Tdu ′ without the back pulse is longer than the movement duration Tdu of the mover 102 in the ninth embodiment, the performance such as the number of divided injections is limited.

Further, by applying a back pulse based on the detection information of the valve closing delay time of each cylinder, the valve closing collision speed when the valve body 114 closes can be reduced. Kinetic energy can be reduced, and the amount of displacement when the movable element 102 after closing the valve is separated from the valve body 114 can be reduced. Due to this effect, it is possible to shorten the time from when the movable element 102 is separated from the valve body 114 after closing the valve to contact with the valve body 114 again, and to reduce the divided injection interval. This is advantageous when performing multi-stage injection that requires multiple floor fuel injection. The application of the back pulse has the effect of reducing the collision speed between the valve body 114 and the valve seat 118 even in an intermediate lift state where the valve body 114 does not reach the target lift, and is combined with the effect of reducing the divided injection interval by the intermediate lift. Thus, it is advantageous when performing multi-stage injection. When driving with an intermediate lift, the magnetic attraction force required to decelerate the valve body 114 is smaller because the collision speed between the valve body 114 and the valve seat 118 is lower than when the valve is closed from the target lift position. Therefore, under the intermediate lift conditions, it is preferable that the back pulse is applied from the battery voltage VB lower than the boost voltage VH, and the back pulse is applied from the boost voltage VH when the valve is closed from the target lift. . By applying the back pulse with the battery voltage VB under the condition of intermediate lift, the load on the booster circuit can be reduced, and the voltage value of the boosted voltage VH at the time of the next injection request is restored to the initial set value. Therefore, it is possible to reduce the injection amount variation for each shot. Further, the voltage source to which the back pulse is applied may be switched using the detection information of the valve opening completion timing of the fuel injection device of each cylinder where the valve body 114 reaches the target lift. Due to this effect, an appropriate back pulse voltage can be applied to each fuel injection device, so that the effect of reducing the divided injection interval and the accuracy of the injection amount can be increased. In addition, when the back pulse is applied, the detection sensitivity of the valve closing completion timing is lowered. Therefore, when the valve closing completion delay time Tb is detected and the characteristics of the fuel injection device 640 are grasped, the detection mode is operated and the back pulse is Injecting with a non-stroke operation, learning the valve closing completion delay time, and switching to an operation mode in which a back pulse is applied enables operation with higher control accuracy.

When the fuel injection device is driven by the method in the eighth embodiment, the collision speed when the valve body 114 comes into contact with the valve seat 117 can be reduced, so that the valve body 114 and the movable element 102 are integrated. This is advantageous when a valve structure is used. In the structure using the movable valve, when the movable valve comes into contact with the valve seat 117, the movable element 102 and the valve body 114 are larger by the mass of the movable element 102 than the separate structure. In some cases, unintended injection may occur, and under such conditions, the injected fuel has a large particle shape, which makes it difficult for the fuel to vaporize and causes the exhaust performance to deteriorate. By using the control method of the eighth embodiment, unintended fuel injection can be suppressed by the effect of reducing the collision speed even when a movable valve is used. By using the movable valve, the number of parts can be reduced, and the structure of the fuel injection device can be simplified and the cost can be reduced.

The method of reducing the injection amount by the method of the eighth embodiment is the same as the control method of the fifth embodiment, but the control method according to the fourth embodiment, the control method of the sixth and seventh embodiments, You may combine the control method of 8th Example which hits a back pulse. By combining the control methods, it is possible to obtain a synergistic effect of driving noise reduction at the time of valve closing by back pulse and driving noise reduction at the time of valve opening by current interruption. Therefore, the noise of the fuel injection device 640 can be reduced, and the noise reduction performance of the engine can be improved. Therefore, it is not necessary to use unnecessary sound insulation and sound insulation materials for the engine, thereby reducing the cost of the engine. can do.

A control method in the ninth embodiment of the present invention will be described with reference to FIG. When the boosted voltage VH is applied to the solenoid 105 at the timing of time T5, the control method is based on the method of FIG. 17 to FIG. Applying boosted voltage VH. Before the time T5, the application of the drive voltage to the solenoid 105 is interrupted, and thereby the magnetic attractive force is reduced, the valve closing force exceeds the magnetic attractive force, and the valve body 114 is in a decelerating state. The difference between the valve closing force and the valve opening force becomes small, and the behavior of the valve body 114 may become unstable. If the speed of the valve body 114 is zero and the deceleration is applied when the valve body 114 reaches the target lift, the valve body 114 moves in the valve closing direction. May become unstable. Therefore, at the timing when the valve body 114 reaches the target lift, it is necessary that the magnetic attraction force and the valve closing force are close to each other or the magnetic attraction force exceeds the valve closing force. Therefore, the battery voltage VB As compared with the case where the magnetic attractive force is generated by applying the voltage, when the magnetic attractive force is generated by applying the boosted voltage VH, the rise of the magnetic attractive force is accelerated, and the application timing of the voltage can be delayed correspondingly. The time when the body 114 reaches the target lift is approached. As a result, the time accuracy of the control for smoothly landing the valve element 114 in the target lift state and reducing the overshoot can be increased, the overshoot can be further reduced, and the movable element 102 and the fixed core 107 can be reduced. It is possible to achieve both a reduction in the collision speed and an improvement in the stability of the valve body 114 after opening.

The method in the ninth embodiment can be used in combination with the fifth control method, and can also be used in combination with the sixth, seventh, and eighth control methods.

FIG. 35 shows the relationship between terminal voltage, drive current, valve body drive force, valve body displacement and time when the fuel injection device 640 is driven by the control method of the tenth embodiment of the present invention. In FIG. 35, the difference from the fourth control method is that, at the time T3 when the application of the boost voltage VH is stopped, the switch operation is not performed so that the reverse voltage is applied at the same time. A time Tg is provided so that After the set time Tg has passed, the boosted voltage VH in the negative direction is applied. Applying the boost voltage VH in the driving direction is an operation for accelerating the movement of the valve body 114, and applying a voltage in the reverse direction is an operation for decelerating the movement of the valve body 114. In the meantime, providing a time zone in which the applied voltage is 0 is close to an operation for moving the valve body 114 at a constant speed, and is effective for lifting the valve body 114 at a constant speed. When the movement of the valve body 114 is stabilized by this operation, control for reducing the overshoot that occurs when the valve body 114 reaches the target lift becomes easier. The control method in the eleventh embodiment of the present invention can be used in combination with the fourth control method, and can also be used in combination with the control methods in the fourth to fourth embodiments.

The eleventh example of the present invention is an embodiment showing an example in which the fuel injection device described in Embodiments 1 to 10 and the control method thereof are mounted on an engine.

FIG. 36 shows an in-cylinder direct injection gasoline engine, and the fuel injection devices A01A to A01D are installed so that fuel spray from the injection holes is directly injected into the combustion chamber A02. The fuel is boosted by the fuel pump A03, sent to the fuel pipe A07, and delivered to the fuel injection device A01. The fuel pressure varies depending on the balance between the amount of fuel discharged by the fuel pump A03 and the amount of fuel injected into each combustion chamber by the fuel injection device provided to each cylinder of the engine, but based on information from the pressure sensor A04. The discharge amount from the fuel pump A03 is controlled with a predetermined pressure as a target value.

The fuel injection is controlled by the injection pulse width sent from the ECU engine control unit (ECU) A05. This injection pulse is input to the drive circuit A06 of the fuel injection device, and the drive circuit A06 is based on a command from the ECU A05. Thus, the drive current waveform is determined, and the drive current waveform is supplied to the fuel injection device A01 for a time based on the injection pulse.

Note that the drive circuit A06 may be mounted as a component or a board integrated with the ECU A05.

The ECU A05 and the drive circuit A06 have the ability to change the drive current waveform depending on the fuel pressure and operating conditions.

In such an engine, when the ECU A05 has the ability to detect the opening and closing operations of the fuel injection device A01 as described in the first to ninth embodiments, the engine can be easily controlled, A method for reducing engine exhaust by reducing exhaust or reducing variation in combustion pressure between cylinders will be described.

In the ECU A05 used for the engine shown in FIG. 36, the injection pulse width of the fuel injection device A01 is corrected so that the amount of fuel injected from the fuel injection devices A01A to A01D approaches the value required by the ECU A05. ing. That is, in a multi-cylinder engine, drive pulses having different widths corrected for each cylinder are given to the respective fuel injection devices.

For example, for a fuel injection device that drives with a short pulse width for a fuel injection device that injects a large amount of fuel when the same command pulse width is given, and for a fuel injection device that injects a small amount of fuel when the same pulse width is given Drive with a long pulse width. By having an operation mode in which such correction is performed for each cylinder, it is possible to suppress variations in the fuel injection amount between the cylinders.

Furthermore, in the ECU A05 shown in FIG. 35, the drive current supplied to the fuel injection devices A01A to A01D of each cylinder is supplied as a waveform adjusted for each fuel injection device.

Each current waveform is set so that the valve behavior of each fuel injection device A01A to A01D is reduced so that the rebound behavior at the time of valve opening is reduced. As a result, the relationship between the injection pulse width and the injection amount is a straight line. It can be set so that the range of the pulse width approaching is widened.

For example, in order to reduce the rebound behavior when the valve is opened, the time during which the boost voltage source is energized in the drive waveform is adjusted according to the valve opening timing of each fuel injection device, The valve is set to decelerate and the valve decelerates. For example, for a fuel injection device that opens early when a certain current waveform is applied, the timing for stopping energization from the boost power supply is advanced, and for fuel injection device 640 that opens late, the power supply cutoff timing from the boost power source Set slower.

In this way, by using a drive waveform that cuts off the energization from the boosting power source and decelerates the valve opening operation, it is possible to reduce the change in the injection amount with respect to the change in the injection pulse width Ti in the region of the minute injection amount. This also has the effect of facilitating correction of the injection amount based on the injection pulse width Ti.

By providing the drive current waveform in which the valve body 114 decelerates in this manner in accordance with the variation in the valve opening timing of the cylinder fuel injection device, a current waveform suitable for the fuel injection device of each cylinder can be provided. The range in which the relationship between the pulse and the injection amount is linear can be increased.

Also, it is preferable to adjust the energization current value (holding current value) for holding the valve open state in the drive waveform according to the valve closing timing of each fuel injection device. When the valve closing timing obtained when the fuel injection device is driven with a certain driving current waveform is late, the holding current value is set small, and when the valve closing timing is early, the holding current value is relatively large. Set. Thus, by setting the holding current value in the drive current waveform in accordance with the state of the fuel injection device, it is possible to prevent an excessive current value from being given. By not giving an excessive current value, the response delay time of the valve closing can be reduced when the injection pulse width is small, and the range of the injection amount in which the relationship between the injection pulse width and the injection amount is a straight line, Can be expanded to the smaller side.

In this way, in an engine in which the drive current waveform and drive pulse width are adjusted and given to each fuel injection device by the ECU, the drive current waveform and drive pulse are set according to the manufacturing variation and state of each fuel injection device. Therefore, the ECU 05A reads the valve opening and closing timing as the state of each fuel injection device.

When reading the valve opening and closing timings of each fuel injector, it is preferable to operate each fuel injector with a drive current waveform that makes it easy to detect the timing of the on-off valve. However, in a drive current waveform that is easy to detect, the linear relationship between the ejection pulse width and the ejection amount may not necessarily be widened.

For this reason, the ECU 05A may have power for setting a drive current waveform for reading the state of the fuel injection device. For example, the fuel injection device for each connected cylinder using a drive current waveform for reading the behavior of the valve body 114 in a situation where the injection amount is not necessarily minimum, such as during warm-up after the engine is started. Is detected and recorded in a memory in the ECU 05A.

Based on this recorded information, the ECU 05A adjusts the drive current waveform and the drive pulse width given to each cylinder, thereby making it possible to control and inject to a smaller injection amount.

Thus, by setting a drive waveform for reading the state of the fuel injection device and recording the state of the fuel injection device in a specific engine operation state, the injection amount can be corrected and controlled. The minimum injection amount can be reduced. Further, in the method of performing such learning, it is possible to monitor the state of deterioration of the fuel injection device over time, so that even if the operation of the fuel injection device changes due to deterioration over time, the controllable injection amount The minimum value can be kept small.

In addition to the warm-up after engine startup, the specific engine operating state can be adjusted with the command from ECU 05A during idling, during the engine startup process, and several cycles after engine key-off. The state in which the injection amount is not remarkably small is an easy period.

Further, the timing of opening and closing the fuel injection device is recorded in the memory in the ECU, and the injection pulse width and the drive current waveform are corrected for each fuel injection device of each cylinder. However, the timing of the valve operation may be further detected for each injection and reflected in the pulse width command value from the ECU. In particular, when the valve closing completion timing, which is a valve closing operation, is detected by detecting the voltage between the terminals of the solenoid 105 of the fuel injection device or the potential difference between the ground potential (GND) side terminal of the solenoid 105 and the ground potential. Since this can be detected without using a detection-dedicated waveform, it is possible to detect the valve closing completion timing for each fuel injection. By feeding back this detection result to the injection pulse width Ti at the next injection, the control accuracy of the fuel injection amount can be further improved and the change in the operation of the fuel injection device due to the engine temperature, vibration, etc. is corrected. become able to.

In this way, as a result of being able to control to a smaller injection amount and use it in an internal combustion engine, it becomes possible to control the injection amount to a smaller injection amount and perform fuel injection, for example, idle stop, etc. This makes it possible to perform combustion at a low load such as recovery from a fuel cut, and it is easy for the engine to have low fuel consumption. In addition, since A / F can be brought close to the target value, gases such as HC and NOx contained in the exhaust gas can be suppressed. Furthermore, since the fuel injection amount is reduced, the fuel to be injected during one stroke of the engine can be divided and injected several times in the low load range, and as a result, the spray penetration force is reduced. Or the control of forming an air-fuel mixture, fuel adhering to the combustion chamber wall surface is suppressed, and soot emissions that are part of PM (particulate matter) and PN (PM particle number concentration) are reduced. Can be connected.

A twelfth embodiment of the present invention will be described. In the method of the present embodiment, individual information of the fuel injection device 640 is given as initial information to a chip having a two-dimensional barcode or storage memory at the shipment stage of the fuel injection device, and the individual device for each fuel injection device is provided by the drive device. By reading the information, calculating a deviation value of the injection amount with respect to the required injection amount, and correcting the drive current and the injection pulse width for each fuel injection device of each cylinder, individual variations in the injection amount can be reduced.

In the twelfth embodiment of the present invention, the initial information of the fuel injection device 640 includes the timing of completion of opening and closing as measured on the mass production line for manufacturing the fuel injection device 640, the displacement amount of the valve body 114 and the orifice cup. The flow rate per unit time measured by the 116 parts alone and the flow rate per unit time when the fuel injection device 640 is assembled may be given.

Using the information of the valve opening completion timing read by the driving device, the peak current value I _peak and the current cutoff period T2 are adjusted. The valve opening completion timing differs for each fuel injection device, but the peak current value for each fuel injection device of each cylinder is set so that the time of the current interruption timing preset in the drive device from the valve opening completion timing is constant. I _peak should be set. In addition, the technique in the twelfth embodiment can be used in combination with the techniques in the fourth to tenth embodiments. By grasping the individual information of the fuel injection device as the initial information, it is not necessary to perform initial detection, and an appropriate current waveform and injection pulse width can be given to each individual fuel injection device. By correcting the change in the operation using the detection information of the opening / closing timing, it is possible to suppress the time-series change in the injection amount. Further, in the intermediate lift, the injection amount can be accurately controlled by detecting the valve opening completion timing and correcting the injection pulse width or the peak current value I _peak after the next injection.

Further, when the initial information is used, the injection amount may not be corrected by adjusting the load of the set spring 110. By not correcting the injection amount by the set spring load 110, the load of the spring 110 becomes constant, and the individual variation of the valve opening start timing of the valve body 114 is reduced. On the other hand, the squeeze force when the valve body 114 closes from the target lift position varies for each individual fuel injection device 640 due to the variation in the dimensional tolerance of the height of the protrusion provided on the mover 102, and the injection pulse width Ti The valve closing completion timing from when the valve is stopped until the valve body 114 closes greatly varies. By adopting such a configuration, it is possible to suppress fluctuations in the valve opening start timing when the valve body 114 is driven under the condition of the intermediate lift, so that fuel for each fuel injection device of each cylinder is started to be injected. Since the timing deviation until the injection is completed can be reduced, the combustion performance and the exhaust performance at the time of multistage injection in which the spray reach distance is related can be improved. On the other hand, the valve closing completion timing when the valve body 114 stops the injection pulse width Ti from the stationary state to the target lift and the valve body 114 is closed greatly varies. The peak current value I _peak , the drive voltage cut-off time Tc, and the holding current Ih are preferably adjusted for each individual using the valve completion timing information. Under the condition that the valve element 114 reaches the target lift with the holding current Ih, increasing the holding current Ih increases the magnetic attraction force. Therefore, the time required for closing the valve increases, and the timing for closing the valve is delayed. The valve delay time can be increased. Further, when the holding current Ih is reduced, the magnetic attractive force is reduced, so that the time required for valve closing is reduced, the valve closing completion timing is advanced, and the valve closing delay time can be reduced.

In the thirteenth embodiment, as shown in FIG. 37, the control methods described in the first to eleventh embodiments are separated from the

movable body

3705 and 3704 operated by the magnetic attraction force and the valve body 3701 of the fuel injection device. It is an Example which shows the case where it applies to an injection device. In the fuel injection device shown in FIG. 37, an enlarged view of the drive unit in a closed state where both the

movers

3705 and 3704 and the valve body 3701 are stationary is shown in FIG. 38, and the

movers

3705 and 3704 and the valve body 3701 are FIG. 39 shows an enlarged view of the drive unit in a valve-open state that is stationary at the target lift position. 38 and 39, components similar to those in FIG. 37 are denoted by the same symbols as in FIG. FIG. 40 shows the relationship between the valve body displacement when the general fuel injection device described in the first embodiment is used, the valve body displacement when using the fuel injection device of the thirteenth embodiment, and time. . In the valve body displacement amount of FIG. 40, the valve body displacement amount of the fuel injection device of the first embodiment is indicated by a dotted line, and the valve body displacement amount of the fuel injection device of the thirteenth embodiment is indicated by a solid line.

In the fuel injection device shown in FIG. 37, at a timing before the opening of the valve body 3701 from the closed state, the mover 3705 performs a preliminary movement in the valve opening direction, and the valve body 3701 opens. The movable element 3704 can preliminarily perform movement in the valve closing direction at a timing before the closing operation is started from the valve state.

That is, in the valve closing state, the movable element 3704 is biased in the valve closing direction by the spring 3706, and the movable element 3704 biases the valve body 3701 and the movable element 3705 in the valve closing direction and is stationary. . Here, the movable element 3704 is urged in the valve opening direction by the second spring 3712, and the valve body 3701 and the movable element 3704 are stationary in a separated state. For this reason, even if current is supplied to the solenoid 105 and the mover 3704 starts to move due to the magnetic attractive force, the valve body 3701 remains stationary. The valve body 3701 starts an opening operation after contacting the movable element 3704.

39, both the movable element 3704 and the movable element 3705 are attracted to the fixed core 107, and the valve body 3701 is maintained in the open state by contact with the movable element 3704. However, the movable element 3704 and the movable element 3705 are separated from each other and have a gap 3901. When the supply of current to the solenoid 105 is interrupted in this state, the magnetic attraction force decreases, and the mover 3705 starts to move in the valve closing direction. However, the movable element 3704 facing the fixed core 107 in a wider area cannot immediately perform the valve closing operation due to the remaining magnetic attraction force or fluid resistance force such as the squeeze effect. In addition, since the load by the spring 110 acts only on the movable element 3705 in the valve open state, the movable element 3705 starts the valve closing operation before the movable element 3704. When the mover 3705 preliminarily starts to move in the valve closing direction and collides with the mover 3704, the mover 3704 can quickly close the valve.

In the fuel injection valve having such a mechanism, the operation of the valve body 3701 is changed according to the driving current waveform, the voltage between the terminals of the solenoid 105 or the ground potential of the solenoid 105 (by the driving device and the control method described in the first to eleventh embodiments). If the detection information of the valve closing completion timing detected from the potential difference between the (GND) side terminal and the ground potential (GND) is used, more precise control of the injection amount becomes possible.

By performing a preliminary operation when the movable element 3704 is opened, the movable element 3704 can have a speed before the valve element 3701 actually starts to move, so that the valve element 3701 and the movable element 3704 collide during the opening operation. Then, the operation of the mover 3704 is rapidly decelerated and the acceleration changes. This change in acceleration can be read as a change in the current supplied to the solenoid 105, and the ECU connected to the fuel injection device can detect the start timing of the valve operation. As described above, in the fuel injection device in which the mover can perform the preliminary operation during the valve opening operation, the start timing of the valve operation can be detected. Therefore, the information on the start timing of the valve operation detected in one injection stroke is fed back. Thus, the valve operation can be controlled. In the fuel injection device controlled in this way, when the conditions such as the fuel pressure and the injection amount change or in the transient state, the fuel injection has a mechanical variation in the valve operation. Even when a valve is used, the valve can be operated with a desired opening / closing delay time.

40, when the movable element 3704 performs a preliminary operation when the valve is opened, the valve element 3701 receives the kinetic energy of the movable element 3704 and opens sharply as indicated by 4003. The gap between 3604 and the fixed core 107 changes sharply, and the induced electromotive force generated in the magnetic circuit also changes greatly. Therefore, when the valve opening completion timing of the fuel injection device described in the first, second, and third embodiments is detected, a change in current when the valve opening is completed becomes significant, so that the valve opening completion timing is easy to detect.

Even during the valve closing operation, the mover 3604 starts to operate preliminarily before the valve body 3601 starts the valve closing operation, and the mover 3605 starts the valve closing operation by the collision of the mover 3604. The acceleration at that moment is large. Therefore, the moment when the operation of the mover 3604 starts can be read as a change in the voltage between the terminals of the solenoid 105 of the fuel injection valve or the potential of either the terminal relative to the ground. Further, compared to the fuel injection device of the first embodiment, the movable element 3605 starts the valve closing operation by the collision of the movable element 3604, and therefore the valve closing completion timing is relatively earlier. Therefore, compared with the fuel injection device of the first embodiment, the magnetic attractive force remaining in the magnetic circuit at the valve opening completion timing is increased, and as a result, the induced electromotive force generated in the voltage between the terminals is also increased. Therefore, the change in acceleration of the mover 3704 due to the mover 3704 being separated from the mover 3705 can be easily detected by the maximum value of the second-order differential value of the voltage between the terminals or the minimum value of the second-order differential value of the voltage _VL. Thus, since the detection error is relatively small, the injection amount can be controlled with high accuracy.

As described above, the driving device and the control method according to the first, second, and third embodiments and the control method according to the fourth to eleventh embodiments are used for the fuel injector configured as a mover that performs the preliminary operation in the thirteenth embodiment. Thus, it becomes easy to detect the start timing of the on-off valve operation of the valve body 3701. By feeding back the start timing of these operations, it becomes possible to perform the valve operation with less variation, and also to perform feedback in one injection.

A fourteenth embodiment of the present invention will be described with reference to FIGS. FIG. 41 is a diagram showing the configuration of the drive device in the fourteenth embodiment. In FIG. 14, the same symbols are used for the same parts as in FIGS. FIG. 42 shows the drive current after the injection pulse is turned off, the valve body displacement amount, the voltage V _HL between the terminals of the fuel injector 640 on the Hi side reference, the ground potential (between the terminals of the fuel injector 640 on the Hi side) is a graph showing the relationship between the voltage V _L and the time between the ground potential of the voltage V _H and the fuel injection device 640 (GND terminal and the ground potential (GND) between the GND). V in FIG. 42 _HL, In V _H and V _L , voltages when the capacitances of the

capacitors

4150 and 4151 are increased are indicated by broken lines, and Fig. 43 is a diagram showing details of the multiplexer 4101 of the driving device of Fig. 41. 14 in the 14th embodiment differs from the third embodiment in that the signals of the input voltage and the output voltage are respectively supplied to the Hi side (voltage side) and the ground potential (GND) side of the fuel injection device 640. Capacitor 4150 to protect against surge voltage and noise 4151, a resistor 4152 is provided in parallel with the capacitor 4150 downstream of the fuel injection device 640, and a multiplexer 4101 is provided between the ground potential (GND) side terminal of the fuel injection device 640 and the analog differentiation circuit 1501. It is.

First, the configuration of the driving apparatus in the fourteenth embodiment will be described with reference to FIG. In the method according to the fourteenth embodiment,

capacitors

4150 and 4151 are provided on the Hi side (voltage source side) and the ground potential (GND) side of the fuel injection device 640, respectively, so that the input voltage of the solenoid 105 of the fuel injection device 640 and When current or noise associated with the surge voltage occurs in the output voltage signal, charges are accumulated in the

capacitors

4150 and 4151 instead of the solenoid 105, so that the solenoid 105 is protected from the influence of the surge current and noise associated with the surge voltage. It becomes possible to do. Further, by arranging the resistor 4152 in parallel with the capacitor 4150, after the injection pulse Ti is turned OFF and the current becomes 0 A, the resistor 4152 is connected to the resistor 4152 through the path on the ground potential (GND) side of the fuel injection device 640. Since the leakage current can flow, the change in the acceleration of the movable element 102 due to the separation of the movable element 102 from the valve element 114 at the moment when the valve element 114 comes into contact with the valve seat 118 is stabilized at the voltage _VL. It is possible to detect, and it is possible to improve the accuracy of the injection amount by improving the detection accuracy of the valve closing completion timing.

Next, with reference to FIG. 42, the relationship between the drive current, the valve body displacement amount, the voltage V _HL , the voltage V _H , the voltage V _H and the time after stopping the injection pulse in the fourteenth embodiment will be described. When the injection pulse is turned off, an induced electromotive force is generated in the solenoid 105 of the fuel injection device 640, and the voltage value of the inter-terminal voltage V _{HL on} the Hi side reference of the fuel injection device 640 is suddenly increased to the boost voltage VH in the negative direction. This voltage is accumulated in the capacitor 4152. After the timing t ₄₂₁ the current value of the driving current supplied to the solenoid 105 is zero, the charge stored in the

capacitor

4151,4152 is discharged, slightly voltage 4201 occurs in the voltage V _H, the voltage V _L, As shown by 4202, it falls sharply. Thereafter, when the timing t _{422 at} which the voltage V _HL becomes 0 is reached, thereafter, both the voltage V _HL and the voltage V _L gradually decrease, the valve body 114 collides with the valve seat 118, and the movable element 102 moves to the valve body. At the valve closing completion timing t ₄₂₃ that is separated from 114, bends 4203 and 4204 are generated in accordance with changes in the acceleration of the movable element 102 at the voltages V _HL and V _L , respectively. Under the conditions described above, it is possible to detect the valve closing completion timing with the voltages V _HL and V _L. On the other hand, as indicated by the broken line in the figure, when the capacitances of the capacitor 4150 and the capacitor 4151 are significantly large, the voltage V _H remains at the valve closing completion timing t ₄₂₃ , so that the valve is closed at the voltage _VL . Although the completion timing cannot be detected, on the other hand, the change in acceleration of the movable element 102 when the valve element 114 comes into contact with the valve seat 117 and the movable element 102 is separated from the valve element 114 is bent 4205 of the voltage V _H. Can be detected as the valve closing completion timing _t423 . Further, since the sum of the voltage V _H and the voltage V _L to the voltage V _HL, if the detected voltage V _HL is a voltage across the solenoid 105, the valve closing completed without depending on the capacitance of the

capacitor

4150,4151 Since timing can be detected, there is a merit that circuit design becomes easy.

Also, the profile of the voltage 4201 is determined by the magnitude relationship between the leakage current from the capacitor 4501 and the induced electromotive force of the solenoid 105. Since the magnitude of the induced electromotive force also changes depending on the inductance and resistance of the magnetic circuit and the way the magnetic gap changes, the values of the

capacitors

4150 and 4151 and the resistor 4152 should be adjusted for each specification of the fuel injection device 640. Thus, the detection accuracy of the opening / closing timing can be improved, and the injection amount can be accurately controlled.

A time T421 of the injection pulse Ti after OFF until timing t ₄₂₁ the current value of the driving current flowing through the solenoid 105 is 0A, the injection pulse Ti after OFF until timing t ₄₂₂ to the voltage V _HL becomes 0 The magnetic constant t (T ₄₂₁ -T ₄₂₂ ) = C · R of the circuit is determined by the two parameters at time T ₄₂₂ . In order to detect the valve closing completion timing with the _VL voltage, the capacitances of the

capacitors

4150 and 4151 are set so that the magnetic constant t of the circuit becomes smaller than the time T423 from when the injection pulse Ti is turned OFF until the valve closing completion timing t423. And the value of the resistor 4152 may be adjusted.

Next, a method for detecting the valve opening completion timing in the fourteenth embodiment of the present invention will be described. At the valve opening completion timing, the switch 607 and the switch 606 of the driving device are ON and the switch 605 is OFF. Therefore, the IC 602 can detect the voltage across the resistor 613 and the resistor 608 provided for current detection. it can.

When the voltage for detecting the valve opening completion timing is detected by an analog circuit, a multiplexer 4101 is provided between the ground potential (GND) side terminal of the fuel injection device 640 and the analog differentiation circuit 1501. Good. The multiplexer 4101 is connected to the terminals A ₀ , A ₁ , A ₂ , and EN of the CPU 601 and can switch between the inputs X ₁ and X ₂ by a signal from the CPU 601. Since it is necessary to measure the voltage across the resistor 608 when detecting the valve opening completion timing, the input X _{1 of the} multiplexer 4101 is turned OFF using the signals A ₀ , A ₁ , A ₂ from the CPU 601, to oN the input X _2. Further, when detecting the valve closing completion timing, since the switch 606 is OFF, it is necessary to see the potential difference between the ground potential (GND) side terminal of the fuel injection device 640 and the ground potential (GND). Using the signals A ₀ , A ₁ and A ₂ from the CPU 601, the input X _{2 of the} multiplexer 4101 is turned OFF and the input X ₁ is turned ON. By using the multiplexer 4101, the opening / closing timing can be detected by one analog differentiation circuit 1501, the cost of the fuel injection device can be reduced, and the circuit size can be made compact. .

Next, details of the multiplexer 4101 in the driving apparatus of FIG. 41 will be described with reference to FIG. In the case of a 4-cylinder engine, the multiplexer 4101 has an 8-input, 1-output configuration in which X ₁ and X ₂ for detecting the opening / closing timing are input for each fuel injection device 640 of each cylinder. In the multiplexer 4101, the multiplexer 4101 can be enabled or disabled by a signal from the terminal EN of the CPU 601, and in a disabled state, all input channels may be switched off. By providing the terminal EN in the CPU 601, it is not necessary to use the multiplexer 4101 under the condition that the opening / closing timing is not detected. Therefore, the power consumption of the circuit can be reduced by disabling the EN terminal of the CPU 601. It becomes possible.

Further, the multiplexer 4101 converts the 3-bit binary data of A ₀ , A ₁ , and A ₂ for controlling each switch of the multiplexer 4101 into a decimal signal for selecting each switch S1 to S8. It is preferable to provide a DECODER for conversion. With the 3-bit signals A ₀ , A ₁ , and A ₂ for controlling the multiplexer 4101, eight data patterns can be constructed. For example, in a four-cylinder engine, the first cylinder to the fourth cylinder Since the injection timings of the fuel injection devices 640 do not overlap, the opening and closing timings of the fuel injection devices 640 from the first cylinder to the fourth cylinder are different, so that each of the inputs X1 and X2 is processed by one multiplexer 4101. Is possible. According to the method of the present embodiment, the opening / closing timing of each cylinder can be detected by one multiplexer 4101 and one analog differentiating circuit 1501, so that the cost of the driving device is reduced and the circuit size is increased. There is an advantage that can be made compact.

Further, the output signal from the multiplexer 4101 may be input to the I / O port of the CPU 601 or the IC 602 through two analog differentiating circuits 1501 and a comparator. As for the voltage input to the CPU 601 or the IC 602 via the comparator, it is preferable to use only a signal for a certain period triggered by ON / OFF of the injection pulse width for determination of the opening / closing timing. With such a configuration, the differential value of the voltage increases at the moment when the switches S1 to S8 are turned on, and the possibility of erroneous detection of the opening / closing timing can be reduced. -The valve closing completion timing can be detected more accurately, the detection robustness can be improved, and the injection amount can be accurately controlled.

Further, in order to detect a change in acceleration of the movable element 102 when the valve element 114 comes into contact with the valve seat 117 and the movable element 102 moves away from the valve element 114, the second-order differential value of the inter-terminal voltage V _inj is maximum. It is necessary to detect the time when the value or the second-order differential value of the voltage _VL between the terminal on the ground potential (GND) side of the fuel injection device 640 and the ground potential (GND) becomes the minimum value. The maximum value of the second-order differential value of the voltage V _inj between terminals or the minimum value of the second-order differential value of the voltage VL coincides with the timing when the third-order differentiation exceeds 0 or falls below 0, so the valve opening completion timing is detected. The third-order differential value of the voltage to be matched is the same as the differential rank. In such a configuration, the analog differentiating circuit 1501 necessary for detecting the opening / closing timing can be used in the same configuration, and the cost of the driving device can be reduced.

In addition, when the differential rank of the voltage for detecting the valve opening completion timing and the valve closing completion timing is different, two multiplexers are provided to detect the valve opening completion timing and the valve closing completion timing, respectively. By using a portion having the same floor number in combination, an increase in the number of parts can be suppressed to a minimum. Note that even when the voltage differentiation order is different, the analog differentiation circuit 1501 that performs the first-order voltage differentiation process can be used in common.

In addition, the current profile in the section in which a constant voltage is supplied changes depending on the magnitude of the induced electromotive force accompanying the displacement of the mover 102, the specifications of the solenoid 105, and the dimensions of the magnetic circuit. Although the current decreases, since the increase in current after the full lift of the mover 102 is small, it may be difficult to make a determination with a threshold value at which the first derivative value of current exceeds zero. In this case, two differentiators having the configuration of the analog differentiating circuit 1501 are arranged between the output terminal of the analog differentiating circuit 1501 and the CPU 601 or IC 602, and a comparator is provided between the output voltage and the CPU 601 or IC 602. Thus, the timing at which the third derivative of the current exceeds the reference voltage of the comparator is determined as the valve opening completion timing, so that the valve opening completion timing can be stably detected regardless of the configuration and specifications of the fuel injection device 640. The injection amount can be controlled more easily.

Further, the CPU 601 and the IC 602 have a plurality of A / D converters and I / O ports (interfaces) for inputting voltages from sensor signals. In general, compared to an A / D converter, an I / O port that determines whether the voltage is 0 or 5 V and reads the state has a higher temporal resolution in principle. Therefore, in the driving device according to the fourteenth embodiment of the present invention, the IC 602 or the CPU 601 detects whether the signal output from the comparator is 0 V or 5 V, so that the timing for completing the opening / closing of the valve can be detected with high accuracy. Therefore, accurate control of the injection amount becomes easier. Further, by passing the detected voltage signal through the analog differentiating circuit 1501, the output signal with respect to the input signal of the analog differentiating circuit 1501 is delayed by the time constant τ ₁ of the analog differentiating circuit. The time constant τ ₁ is determined by the circuit constant of the analog differentiating circuit 1501, and can be adjusted by changing the values of the capacitors C1, C2 and the resistors R1, R2. Therefore, when the values of the capacitors C1 and C2 and the resistors R1 and R2 of the analog circuit 1501 are determined, the time constant τ _{1 is given} to the CPU 601 or the IC 602 in advance, and the opening / closing completion timing detected by the detection voltage is set. By correcting the delay by the constant τ _1, the detection accuracy of the opening / closing timing can be improved.

Further, by determining the peak current value I _peak and the drive voltage cutoff time Tc for each fuel injection device 640 of each cylinder based on the detected valve opening completion timing, the collision speed between the mover 102 and the fixed core 107 is greatly suppressed. can do. In addition, the period between the timing at which the movable element 102 reaches the target lift and the timing at which the movable element 102 decelerates can be kept constant, and individual variations in the collision speed between the movable element 102 and the fixed core 107 can be reduced. Therefore, the fluctuation range of the stress applied to the collision portion between the movable element 102 and the fixed core 107 can be reduced. As a result, it is possible to suppress the wear of chrome plating and the deformation of the magnetic material that may be provided on the collision surface between the movable element 102 and the fixed core 107 due to deterioration of durability, and to change the durability of the target lift and the valve opening state. Since the endurance change of the squeeze force due to the change in the fluid gap between the mover 102 and the fixed core 107 can be minimized, it is possible to reduce the variation due to the deterioration of the injection amount and to increase the accuracy of the injection amount. . In addition, the stress caused by the collision between the movable element 102 and the fixed core 107 is not the collision surface but the maximum value in the metal where stress waves diffused from the collision surface are concentrated. If is large, not the plating layer but the boundary surface between the plating layer and the base material may be peeled off, or the base material of the mover 102 and the fixed core 107 may be deformed. According to the method in the fourteenth embodiment, peeling of the boundary surface between the plating layer and the base material, deformation of the base material, and wear can be reduced, and thus the reliability of the fuel injection device 640 can be improved.

Further, by suppressing the wear and deformation of the collision surface between the movable element 102 and the fixed core 107, the change in the opening / closing timing due to endurance deterioration is reduced, so the frequency of detecting the opening / closing timing is reduced. This can reduce the calculation load of the driving device. In addition, according to the present embodiment, the collision speed between the movable element 102 and the fixed core 107 can be suppressed to a value close to 0 m / s substantially as much as possible, so that the impact force at the time of collision is reduced and the stress applied to the collision portion is reduced. Can be greatly reduced. According to this effect, since it is not necessary to form a plating that may be processed on the collision surface between the movable element 102 and the fixed core 107, the cost of the fuel injection device 640 can be reduced. Also, in the plating process, the surface to be plated is positively charged by using an electrode to form a plating layer. In many cases, a protrusion that may be provided on the collision surface of the mover 102 or the outer diameter of the mover 102 is formed. In the sharp corners such as, the plating film becomes thick and burrs are likely to appear. Therefore, in a complicated shape in which a protrusion is provided on the upper part of the movable element 102, the film thickness of the plating tends to vary, and it may be difficult to manage the fluid gap between the movable element 102 and the fixed core 107. According to the method of the fourteenth embodiment of the present invention, the plating process that may be provided on the mover 102 and the fixed core 107 can be eliminated, and the tolerance width of the fluid gap can be reduced. It becomes possible to increase the accuracy of the.

Hard chrome plating, which is often applied to the impact surface, is not magnetized, so the permeability is close to the vacuum permeability 4π × 10-7 [H / m], and the magnetic circuit magnetism is the same as the chromium plating thickness. The resistance increases and the number of magnetic fluxes that can be generated in the magnetic circuit decreases, and as a result, the magnetic attractive force decreases. Therefore, by eliminating the chrome plating, the distance between the magnetic material of the movable element 102 and the magnetic material of the stator 107 can be reduced by the thickness of the plating, and the magnetic attraction force can be increased. The driveable fuel pressure of the injection device 640 can be improved. In addition, due to this effect, the time until the valve body 114 that cooperates with the mover 102 reaches the target lift after the magnetic attraction force acts on the mover 102 after the current is supplied to the solenoid 107 can be shortened. Since the amount of fuel injected before reaching the target lift can be reduced, the minimum controllable injection amount can be reduced.

Further, in the divided injection in which one injection amount is divided into a plurality of times, it is necessary to perform the injection a plurality of times within a certain time determined by the engine speed. Due to the effect of increasing the magnetic attraction force, the valve opening start timing is accelerated, the divided injection interval can be reduced, and the number of divided injections can be increased, so that the homogeneity of the injected fuel and air is improved and the fuel piston wall surface It becomes possible to suppress the adhesion of, and reduce PM and PN. In particular, the method of the fourteenth embodiment has a synergistic effect combined with the fuel injection device of the thirteenth embodiment, thereby increasing the effect of reducing the divided injection interval and increasing the number of divided injections.
Further, according to the method in the fourteenth embodiment of the present invention, the fuel injection device 640 of each cylinder or the detection information of the valve opening completion timing of the fuel injection device in FIG. 37 is used for each fuel injection device of each cylinder. As a result, it is possible to reduce the absolute value of the velocity and the fluctuation when the movable element 102 collides with the fixed core 107, so that the fuel injection device 640 caused by the collision can be controlled. The driving sound and the fluctuation range of the driving sound can be suppressed, and the quietness of the fuel injection device 640 can be improved. In addition, since the driving sound generated by the collision between the movable element 102 and the fixed core 107 has a high frequency band, it is easy to hear greatly according to Weber-Fechner's law. In general, when the speed at which the movable element 102 collides with the fixed core 107 is large, the driving sound is loud and the frequency band of the sound is high. According to the method of the fourteenth embodiment, the effect of reducing the speed at which the mover 102 collides with the fixed core 107 can reduce the driving sound and the frequency band. Can be increased. Further, by enhancing the quietness of the fuel injection device 640 in the sense of hearing, it is possible to reduce the soundproofing material (silent material) of the engine and reduce the cost of the engine system.

The drive device in the fourteenth embodiment of the present invention is the control method in the fifth embodiment, the control method in the fourth embodiment, the control method in the sixth and seventh embodiments, and the eighth embodiment in which a back pulse is applied. These control methods may be combined. Due to the effect of combining the driving device and the control method in the fourteenth embodiment, the detection accuracy of the valve closing completion timing can be increased, and the injection amount accuracy can be improved.

As described in the above embodiment, the present invention is a control device that supplies a drive current of a valve body to a fuel injection device that drives the valve body to switch between a valve open state and a valve closed state, The control device for the fuel injection device includes means for turning on and off the electrical connection between the first voltage source for the fuel injection device and the second voltage source that generates a voltage higher than the first voltage source, and is in a closed state. When the valve body is operated from the second to the open state, the voltage of the second voltage source is applied to the fuel injection device to supply the valve body drive current from the second voltage source, and then the second voltage source A function of supplying a holding current for holding the valve element from the first voltage source by stopping the application of the first voltage and applying the voltage of the first voltage source to the fuel injection device. By switching the voltage source of the After the valve closing completion timing when the valve body reaches the valve seat, the mover moves away from the valve body, and in the valve closing direction that the mover has received through the valve body until now. The timing at which the acceleration of the mover changes when the force is lost, i.e., the timing at which the direction of the force acting on the mover is reversed, is the voltage across the solenoid or the potential difference between the terminal on the ground potential side of the solenoid and the ground potential. By detecting, the voltage value detected by the control device is second-order differentiated, so that the timing at which the second-order derivative value of the voltage becomes maximum is detected as the valve closing completion timing, and after the injection pulse is stopped, the voltage 2 The valve closing delay time until the floor differential value is maximized is stored in the control device.

In addition, the second voltage source is used to supply current to the solenoid from the valve-closed state, and after the current value reaches the target value, the application of the second voltage source is stopped, and after the elapse of a certain time, the first voltage source is stopped. A constant voltage is supplied from the voltage source to provide a period in which the voltage does not change. During this period, the valve body is reached at a target lift where the mover and the magnetic core collide, so A change in magnetoresistance due to a reduction in the gap is detected by a current value as a change in induced electromotive force.

When the mover is displaced and the magnetic gap between the mover and the stator is changed in the section for supplying the first voltage source, an induced electromotive force is generated, so that the current value decreases, but the moveable When the child reaches the target lift, the gap between the mover and the stator stops changing, and the current value starts to increase from the decrease. By detecting the timing at which the current value changes from decreasing to increasing as the timing at which the differential value of the current becomes 0, it is possible to detect the timing at which the valve body of each cylinder reaches the target lift.

Also, the valve opening delay time, which is the time from when the injection pulse is supplied until the differential value of the current becomes 0, is stored in the control device. The deviation value from the median value of the valve opening delay time and the valve closing delay time previously given to the control device from the information of the valve opening delay time and the valve closing delay time stored in the control device is calculated for each cylinder. Multiply the static flow rate per unit time at each fuel pressure when the valve element that is given to the control device at the target lift in advance to estimate the injection amount of each cylinder and correct the injection pulse width after the next injection This reduces the variation in the injection amount of each cylinder.

In addition, after the injection pulse is applied, the current reaches the target value, and then the negative voltage is supplied from the second voltage source, so that the current is rapidly decreased and the magnetic attractive force acting on the mover By reducing the valve body, the valve body is rapidly decelerated before it reaches the target lift, and the increase in the valve opening delay time due to deceleration is minimized while reducing the valve body bounce after reaching the target lift. Therefore, non-linearity generated in the injection amount characteristic can be improved, and minute control of the injection amount becomes possible. Further, the amount of bounce of the valve body after the valve body generated by the collision of the mover and the fixed core reaches the target lift differs depending on the fuel injection device due to the variation in the dimensional tolerance of the fuel injection device, and is generated in the injection amount. Non-linearity also varies from individual to individual. When the same current waveform is given to an individual with early and late timing for opening the valve body after reaching the target lift after supplying the injection pulse, an individual with early opening timing. Then, the deceleration of the valve body due to the rapid decrease of the current is not in time, the movable element and the fixed core collide at a high speed, and the valve body bound after reaching the target lift increases. Therefore, based on the valve opening delay time detected by the fuel injection device of each cylinder, the application of the second voltage source is stopped and the voltage in the negative direction is supplied to both ends of the solenoid of the fuel injection device to rapidly increase the current. By correcting the timing at which the cylinder is shut off, the fuel injection device of each cylinder can supply an appropriate current waveform, and the valve body bounce after reaching the target lift can be suppressed, thus improving the nonlinearity of the injection amount characteristic. be able to.

Specifically, the following configuration is preferable.
A control device that supplies a drive current of a valve body to a fuel injection device that drives a valve body to switch between a valve open state and a valve closed state, and stops a command injection pulse for supplying a current to a solenoid Later, the valve body and the valve seat come into contact with each other, and the change in the direction of the force acting on the mover due to the mover moving away from or stopping the valve element is detected as a change in acceleration with a voltage.

At this time, it is preferable to detect the time from when the command injection pulse is stopped until the second-order differential value of the voltage becomes maximum.

101 Nozzle holder 102 Movable element 103 Yoke 104 Bobbin 105 Solenoid 107 Fixed core 110 Spring 111 Magnetic throttle 112 Zero position spring 113, 115 Rod guide 114 Valve body 114a Restriction part 114b Rod part 117 Fixed core 116 Orifice cup 118 Valve seat 119 Fuel injection Hole 120 ECU
121 Drive circuit 124 Spring retainer 640 Fuel injection device 601 CPU
602 IC
609, 610, 611, 632, 635

Diode

608, 612, 613 Current, voltage detection resistor 615 Ground potential (GND)
620 Operational amplifier 641 Solenoid ground potential (GND) side terminal 1501 Analog differentiation circuit R1, R2 Resistor C1, C2 Capacitor T1 Valve opening signal start time T2 Valve body movement start time T3 Booster voltage cut-off time T4 Valve body acceleration end time T5 Holding current start time T6 Valve body deceleration end time T7 Valve body lift position arrival time T9 Valve opening signal end time T10 Current extinction time T11 Valve closing movement start time T12 Valve closing completion time T13 Back pulse application time Ti Valve opening signal time ( Ti = T9-T1)
Ta valve opening completion delay time (Ta = T7-T1)
Tb valve closing completion delay time (Tb = T12-T9)
Tp Boost voltage application time (Tp = T3-T1)
Tc Drive voltage cut-off time (Tc = T5-T3)
Td Precharge time Te Back pulse application time Tf Holding current rapid rise pulse application time Tg Reverse voltage application waiting time Vh Boost voltage Vb Battery voltage Ip Peak current value Ih Holding current Ic Precharge current Tn Dead band Tu Down movement period Tdu Movement duration Tdu ′ of the moving element 102 in Example 9 Movement duration Ipd without a back pulse Back pulse current

Claims

A valve body that closes the fuel passage by contacting the valve seat and opens the fuel passage by leaving the valve seat;
A mover held by the valve body so as to be relatively displaceable in the drive direction of the valve body;
A solenoid and a magnetic core for energizing the mover with a magnetic attractive force in a valve opening direction;
In order to control the fuel injection valve that drives the valve body and the mover in the valve opening direction by supplying the current to the solenoid so that the magnetic attractive force acts between the magnetic core and the mover. In the control device of
When the current supplied to the solenoid is cut off and the valve seat and the valve body come into contact with each other, a change in induced electromotive force due to an increase in the distance between the mover and the magnetic core is caused between the solenoid terminals. A control device for a fuel injection valve, characterized in that it is detected as a voltage value.
The fuel injection valve control device according to claim 1,
The change in acceleration of the mover that occurs when the movable valve contacts the valve seat with the current supplied to the solenoid being cut off and the mover moves away from the valve body is second-order differentiation of the voltage value A control apparatus for a fuel injection valve, wherein the detection is performed using a value.
The fuel injection valve control device according to claim 2,
The fuel injection valve includes a first urging unit that urges the valve body in a valve closing direction;
A second urging means for urging the movable element with a force in a valve opening direction smaller than that of the first urging means;
When the movable valve is in contact with the valve seat by cutting off the current supplied to the solenoid, and the movable element is separated from the valve body,
The combined force in the valve closing direction including at least the force received from the first urging means via the valve body is movable to the combined force in the valve opening direction including at least the force received from the second urging means. A control device for a fuel injection valve, wherein a change in force acting on a child is detected using the voltage value.
The fuel injection valve control device according to claim 2,
A control device for a fuel injection valve, wherein a current supplied to the fuel injection valve is varied based on the voltage value.
3. The fuel injection valve control device according to claim 2, further comprising a function of detecting a potential difference between a ground potential side terminal of a solenoid of the fuel injection valve of each cylinder and a ground potential of the driving device, The change in acceleration of the mover that occurs when the mover moves away from the valve body when the valve body collides with the valve seat when the solenoid is de-energized from the valve open state. An apparatus for controlling a fuel injection valve, comprising: detecting a minimum value of a second-order differential value of a potential difference between a terminal on a ground potential side of the solenoid of the fuel injection valve and a ground potential of the driving device.
3. The fuel injection valve control device according to claim 2, further comprising at least one differentiation circuit between a terminal for energizing a solenoid of the fuel injection valve and the driving device. Control device.
3. The fuel injection valve control device according to claim 2, wherein means for turning on and off an electrical connection between a first voltage source and a second voltage source that generates a voltage higher than the first voltage source; Means for turning on and off the electrical connection between the solenoid and the ground potential, and the voltage of the second voltage source at the time of opening the fuel injector to operate the valve body from the closed state to the open state. When the application of the voltage of the second voltage source is stopped after the drive current is supplied to the solenoid to reach a preset current value and the voltage of the second voltage source is stopped, The voltage of the voltage source 2 is applied, and then the valve body is reached to the valve open position while the voltage is applied from the first voltage source, and the differential value of the drive current of the fuel injection valve is When the valve body exceeds the threshold set in advance, the valve body is in the valve open position. The fuel injector control apparatus characterized by having a function of detecting a valve opening completion timing has been reached.
8. The control device for a fuel injection valve according to claim 7, wherein the second voltage source is applied to the solenoid in a negative direction for a certain period of time until the voltage application from the first voltage source is stopped. Period, without turning on and off the electrical connection between the first voltage source and the solenoid;
Fuel injection characterized by detecting a first-order differential of the solenoid current during the period and after elapse of a preset time, and detecting it as a valve opening completion timing when the valve body reaches a valve opening position Valve control device.
The control device for a fuel injection valve according to claim 2, wherein means for turning on and off an electrical connection between a first voltage source and a second voltage source that generates a voltage higher than the first voltage source; Means for turning on and off an electrical connection between the solenoid and the ground potential, and the second voltage source is configured to open the fuel injector when the valve body is operated from the closed state to the open state. Apply a voltage to supply the drive current to the solenoid, and open the time from supplying the injection pulse for driving the fuel injection valve to the timing when the differential value of the drive current of the fuel injection valve becomes zero. The valve delay time is stored for each fuel injection valve of each cylinder, and the time from when the injection pulse is stopped until the maximum of the second-order differential value of the voltage value is set as the valve closing delay time, the fuel injection of each cylinder Memorized for each valve, when the valve opening is delayed And based on the valve closing delay time, the control device of the fuel injection valve and correcting the pulse width of the next and subsequent injection pulse for each fuel injection valve of each cylinder.
3. The fuel injection valve control device according to claim 2, wherein means for turning on and off an electrical connection between a first voltage source and a second voltage source that generates a voltage higher than the first voltage source; Means for turning on and off the electrical connection between the solenoid and the ground potential, and the voltage of the second voltage source at the time of opening the fuel injector to operate the valve body from the closed state to the open state. Is applied to the solenoid to supply a drive current, and then the voltage of the second voltage source when the application time of the second voltage source exceeds a preset set value or when a predetermined time has elapsed. The fuel injection valve control device has a function of correcting the timing of stopping the application of the second voltage source and the timing of stopping the application of the voltage of the second voltage source for each fuel injection valve of each cylinder.
3. The fuel injection valve control device according to claim 2, wherein means for turning on and off an electrical connection between a first voltage source and a second voltage source that generates a voltage higher than the first voltage source; Means for turning on and off the electrical connection between the solenoid and the ground potential, and applies the voltage of the second voltage source to the solenoid when the valve body is operated from the closed state to the open state. Then, before the valve element contacts the magnetic core, a negative voltage is applied to the solenoid from the second voltage source to fix the movable element to the fixed state. The magnetic attractive force that can be held at the position of the core is made smaller than a current value that can be generated, and the time for applying a negative voltage from the second voltage source to the solenoid is adjusted for each fuel injection valve of each cylinder. Controlling a fuel injection valve Location.
12. The fuel injection valve control device according to claim 11, wherein a time for stopping the application of voltage from the second voltage source at the time of opening the valve body to operate the valve body from the valve closing state to the valve opening state is determined. A pressure value attached to a fuel pipe upstream of the fuel injection valve, a set value of a current value set in advance in the control device and a time during which a voltage in a negative direction is applied from the second voltage source thereafter. A control device for a fuel injection valve, which changes based on a signal of a sensor.
10. The fuel injection valve control device according to claim 9, wherein when the injection pulse is applied, a voltage is applied from the first voltage source to the solenoid, and then a voltage is applied from the second voltage source to the solenoid. Applying a negative voltage from the second voltage source to open the valve body by applying the current to supply the solenoid to the current that can hold the mover by the magnetic core Less than a value, and reach the current value that can hold the valve body in contact with the magnetic core at a timing before the mover contacts the magnetic core,
By multiplying the valve opening delay time by a preset correction coefficient, the valve opening start time at which the valve body is separated from the valve seat after applying the injection pulse is calculated for each fuel injection valve of each cylinder, Based on the valve opening start time, the injection pulse width is changed for each fuel injection valve of each cylinder, the valve body is driven under the condition of an intermediate lift that does not contact the magnetic core, and the fuel injection valve of each cylinder is closed. By detecting the completion timing and estimating the valve closing delay time, the deviation value from the valve closing delay time obtained from the command value of the injection amount of the drive device for each fuel injection valve of each cylinder is calculated, and the deviation value The fuel injection valve control apparatus corrects the injection pulse width after the next injection for each fuel injection valve of each cylinder so that the fuel injection is reduced.
14. The control device for a fuel injection valve according to claim 13, wherein the valve body stops an injection pulse from the opened state, the valve body starts a valve closing operation, and the valve body contacts the valve seat. Before applying, the voltage is applied from the second voltage source, and the timing of applying the voltage from the second voltage source is adjusted based on the valve closing delay time detected for each fuel injection valve of each cylinder. The stop timing of the voltage application time from the second voltage source, which is performed before the valve body comes into contact with the valve seat, is the valve closing direction after the valve body comes into contact with the valve seat. The control device for a fuel injection valve is configured to move before the moving amount of the movable element reaches a minimum value.
8. The fuel injection valve driving device according to claim 7, wherein a capacitor is disposed between a ground potential side terminal of the solenoid and a ground potential, a resistor is provided in parallel with the capacitor, and the capacitor and the resistor The fuel injection valve control device is characterized in that a terminal on the fuel injection valve side of the injector is positioned between a ground potential side terminal of the solenoid and switch means provided between the solenoid and the ground potential.