JP3289553B2 - Electromagnetic drive valve control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electromagnetically driven valve control device for an internal combustion engine that opens and closes an intake valve or an exhaust valve of the internal combustion engine by electromagnetic force.

[0002]

2. Description of the Related Art Conventionally, in a vehicle internal combustion engine,
2. Description of the Related Art A technique is known in which an intake valve or an exhaust valve of an internal combustion engine is configured by an electromagnetic drive valve that operates using an electromagnetic force generated by supplying a current to an electromagnetic coil as a drive source, and adjusts a timing of supplying current to the electromagnetic coil. By doing so, it is possible to arbitrarily change the opening / closing timing of the intake / exhaust valve in accordance with the motion state of the internal combustion engine.

As an apparatus using such a technique, for example, Japanese Unexamined Patent Application Publication No. 3-242409 discloses two large and small electromagnetically driven valves as exhaust valves. (Hereinafter referred to as a main valve) is opened prior to a large valve (hereinafter referred to as a main valve).

[0004] The exhaust valve of an internal combustion engine is generally opened under the condition that the combustion pressure remains in the combustion chamber. Therefore, at a high load where the combustion pressure remaining in the combustion chamber is relatively high, a greater force is required to open the exhaust valve than at a low load. Therefore, in the device described in the above publication, when a high combustion pressure remains, the auxiliary valve that can be opened with a relatively small force even when the combustion pressure is high is first opened to reduce the combustion pressure. By opening the main valve after that, the energy required for opening the exhaust valve can be saved.

[0005]

Generally, in a four-stroke engine, four strokes of intake, compression, combustion, and exhaust are performed. In each of the above-described strokes, the pressure in the combustion chamber of the internal combustion engine is higher than the atmospheric pressure. Negative pressure, compression,
It changes to positive pressure during the combustion and exhaust strokes. Therefore, the pressure that changes in the combustion chamber always acts as an external force on the intake valve and the exhaust valve that are mounted in the combustion chamber.

In this sense, the electromagnetic coil of the electromagnetically driven valve in the conventional device can open the exhaust valve even in the exhaust stroke in which the combustion pressure during the combustion stroke exists as a residual pressure in the combustion chamber. To prevent the exhaust valve from opening even when the maximum negative pressure occurs during the intake stroke, and to maintain the closed state, the combustion chamber A predetermined amount of current is set and appropriately supplied so as to generate an electromagnetic force capable of performing a desired valve element opening / closing drive regardless of pressure.

However, for example, when the intake valve is opened during the intake stroke of the engine, the combustion chamber is in a negative pressure state due to the lowering of the piston, and the suction pressure acts on the intake valve in the valve opening direction due to the negative pressure. Will be. Therefore, even if the valve opening force is relatively small, that is, the amount of current supplied to the electromagnetic coil is relatively small, and the generated electromagnetic force is small, the intake valve can be opened and the open state can be maintained. .

Based on the same concept, the combustion chamber is also used for closing and holding the intake valve and the exhaust valve in the compression and combustion strokes of the engine, closing and holding the exhaust valve in the exhaust stroke, and holding the intake valves closed. The pressure acts as an auxiliary force for driving the valve body. Therefore, even if the valve-closing holding force during the compression / combustion stroke and the valve-closing force during the exhaust stroke are relatively small, that is, the amount of current supplied to the electromagnetic coil is relatively small, and the generated electromagnetic force is small. Can be opened and closed.

Nevertheless, the electromagnetic coil of the above-mentioned conventional electromagnetically driven valve is always supplied with a predetermined amount of current which is set in advance in anticipation of the generation of the maximum negative pressure and the maximum positive pressure. However, the amount of current supplied to the electromagnetic coil itself is not adjusted according to the above. Therefore, an excessive amount of current is supplied to the electromagnetic coil of the electromagnetically driven valve, and the current consumption is wasted.

An object of the present invention, opening of a portion of the valve body of the combustion chamber pressure, by using as a driving force in the closing direction, when the lower combustion chamber pressure to open than when high to reduce the supply current amount of the valve-side, or when a high combustion chamber pressure is to improve the small amount of current consumption by reducing the supply current amount of valve-closing side than when low.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to an electromagnetic force generated in an electromagnetic coil by a valve element provided as an intake valve or an exhaust valve in an internal combustion engine. > Therefore the electromagnetic valve for opening and closing, in electromagnetically driven valve control apparatus for an internal combustion engine and a control device for controlling in accordance with generation timing of the electromagnetic force to the engine operating state generated in the electromagnetic coil <br/>, crank An angle sensor detects the current engine combustion cycle, and a rotation speed sensor and a load.
Detecting means for detecting the engine operating region by the sensor, the
For the intake stroke if the detected combustion cycle is the intake stroke
Select the map for the combustion cycle during the compression and combustion strokes.
If available, select a map for the compression / combustion process and
If the vehicle is in the exhaust stroke, select the map for the exhaust stroke,
The detection among the current waveforms shown in the selected map.
Current waveform based on the engine operating area
The method for opening and closing the valve body based on the selected current waveform
Drive supplied to the electromagnetic coil to actuate in the opposite direction
The electromagnetic coil is used to maintain the amount of current and the valve body closed.
Set the amount of holding current supplied to the
And control means for supplying the electromagnetic coil and controlling the electromagnetic coil .

[0012]

[Action] In the invention of claim 1, the combustion cycle and engine operating region of the present engine by the detection means is detected, the control means on the basis of their combustion cycle and engine operating region actuates the valve body in the closing direction Electromagnetic carp to make
And the amount of drive current supplied to the solenoid coil and the amount of hold current to be supplied to the electromagnetic coil to hold the valve closed. Then, the control unit generates an electromagnetic force in accordance with these current amount to the electromagnetic coil of the electromagnetic valve, for opening and closing and <br/> closed valve maintaining the valve body.

[0013]

[0014]

[0015]

[0016]

FIG. 2 shows electromagnetically driven valves 1, 1 'as intake and exhaust valves controlled by an electromagnetically driven valve control apparatus according to one embodiment of the present invention. explain. Since there is no difference in the basic configuration of the electromagnetically driven valves 1 and 1 ', only the electromagnetically driven valve 1 as an intake valve will be described.

Reference numeral 2 denotes a valve body, which is disposed in the cylinder head 3 'with its lower end exposed in the combustion chamber 3 of the internal combustion engine. Further, a valve shaft 4 is fixed to the valve body 2. The valve shaft 4 is slidably held in the axial direction by a valve guide 5 and is fixed to a plunger holder 6 at an upper end thereof. Plunger holder 6
Is a member made of a non-magnetic material, and a donut-shaped plunger 7 made of a soft magnetic material having Fe, Ni, Co or the like as a base material is joined to an outer peripheral portion thereof.

Above the plunger 7, a first electromagnetic coil 8 as an electromagnetic force generating means is arranged at a predetermined distance. Further, a second electromagnetic coil 9 is similarly arranged at a predetermined distance below it. Further, above the plunger 7, a first core 10 holding the first and second electromagnetic coils 8, 9 and a second core 11
Are arranged.

The first and second cores 10 and 11 are both members made of a soft magnetic material, and are held in a predetermined positional relationship by an outer cylinder 12 made of a non-magnetic material.
Further, the first and second cores 10 and 11 have hollow portions near the centers thereof, and springs 13 and 14 for elastically supporting the plunger holder 6 from above and below are accommodated therein. ing.

A spring guide 15 for holding the upper end of the spring 13 is provided at the upper end of the first core 10.
Also, an adjuster 16 for adjusting the amount of deformation of the springs 13 and 14 is provided. In this embodiment, the springs 13 and 14 are balanced by adjusting the adjuster 16 so that the neutral position of the plunger 7 is at the intermediate position between the first and second cores 10 and 11.
In the neutral position of the plunger 7, the valve body 2 is at an intermediate position (middle open position) between the fully open position and the fully closed position.

In the electromagnetically driven valve 1 having such a configuration, the first core 10, the plunger 7, and the air gap formed between the second core 11 and the plunger 7 are formed around the first electromagnetic coil 8. Is formed. Therefore, when a current is passed through the first electromagnetic coil 8, the magnetic flux returns in the magnetic circuit, and the electromagnetic force acts in a direction to reduce the air gap, that is, to move the plunger 7 upward in FIG. I do.

On the other hand, around the second electromagnetic coil 9,
A magnetic circuit including a core 11, a plunger 7, and an air gap formed between the first core 10 and the plunger 7 is formed. When a current flows through the second electromagnetic coil 9, a similar circuit is formed. From the principle, the electromagnetic force acts in a direction to move the plunger 7 downward in FIG.

For this reason, in the electromagnetically driven valve 1,
If a current is alternately passed through the first electromagnetic coil 8 and the second electromagnetic coil 9, the plunger 7 can reciprocate up and down, that is, the valve body 2 can be operated in the opening and closing directions. .

In an internal combustion engine, an electromagnetically driven valve 1 as an intake valve (hereinafter, simply referred to as an intake valve 1) is opened during an intake stroke, and the valve is kept open, and an electromagnetically driven valve as an exhaust valve is opened. 1 '(hereinafter simply referred to as the exhaust valve 1') is kept closed, and a negative pressure is generated in the combustion chamber as the piston descends. At this time, the suction pressure in the valve opening direction acts on the intake valve 1 due to the negative pressure generated in the combustion chamber as a valve opening assisting force. Even when the force is small, it is easy to maintain the valve open state. Further, the suction force due to the negative pressure increases as the engine load decreases. Therefore, the amount of current supplied to the second electromagnetic coil 9 on the valve opening side is set as the maximum value at the time of high load, and the desired valve opening operation is performed at a low load with a smaller amount of current than at the time of high load. By doing, the amount of current supplied to the second electromagnetic coil 9 on the valve opening side during the intake stroke can be reduced, and the amount of current consumption can be reduced.

On the other hand, in the exhaust valve 1 ', as described above, the suction force due to the negative pressure increases as the engine load decreases. Therefore, by setting the amount of current supplied to the electromagnetic coil at a low load to a maximum value, At a high load, it is possible to perform a desired valve closing maintenance with a smaller amount of current than at a low load.

Next, the combustion cycle of the engine shifts to the compression / combustion stroke, and both the intake valve 1 and the exhaust valve 1 'are kept closed. At this time, the pressure in the combustion chamber changes from a negative pressure to a positive pressure as the piston rises, and the positive pressure in the combustion chamber applies a pressing force in the valve closing direction to the intake valve 1 and the exhaust valve 1 'to close the valve. Acts as a force. In this sense, the valve-closing state can be easily maintained even if the valve-closing holding electromagnetic force is small. Further, the pressing force due to the above positive pressure increases as the engine load increases. Therefore, a desired valve closing operation can be performed with a smaller amount of current at a high load than at a low load with respect to a current amount set as a maximum value at a low load, so that the compression / combustion stroke At this time, the amount of current supplied to the first electromagnetic coil 8 on the valve closing side can be reduced, and the amount of current consumption can be reduced.

Next, when the combustion cycle of the engine shifts to the exhaust stroke, the exhaust valve 1 'is opened, the valve is kept open, and the intake valve 1 is kept closed. At this time, a positive residual pressure due to combustion and explosion of the engine is present in the combustion chamber, and the intake valve 1 and the exhaust valve 1 ′ are pressed by the positive pressure remaining in the combustion chamber in the valve closing direction. Working.

Accordingly, the exhaust valve 1 'is basically difficult to open due to the remaining pressing force due to the positive pressure. By setting the amount of current supplied to the electromagnetic coil 9 as a maximum value to perform a desired valve opening operation, and performing a valve opening operation with a small amount of current at a low load compared to a high load, the exhaust stroke is reduced. In this case, the electromagnetic force for driving the exhaust valve 1 'and the electromagnetic force for holding the valve open can be made smaller than the electromagnetic force based on the initially set current amount. The amount of current supplied to the engine can be reduced as the engine load decreases, and the amount of current consumption can be reduced. Further, when the exhaust valve 1 'is shifted to the closed valve operation, the pressing force by the positive pressure of the above-described residual acts as an auxiliary force in the closing direction, the first electromagnetic coil 8 of the valve-closing It is possible to improve the reduction in the amount of current consumption by reducing the amount of current supplied to the device.

On the other hand, in the intake valve 1, since the pressing force in the valve closing direction acts as a valve closing assist force due to the residual pressure generated by the combustion and explosion, even if the valve closing electromagnetic force is small, the valve is closed. It becomes easy to maintain the state. Further, the pressing force due to the residual pressure increases as the engine load increases. Therefore, a desired amount of current is set to be smaller at a high load than at a low load with respect to a current amount set as a maximum value at a low load.
Since it is possible to perform the closing valve operation, it is possible to improve the small amount of current consumption by reducing the amount of current supplied to the first electromagnetic coil 8 of the valve-closing during the exhaust stroke.

In this sense, in this embodiment, the amount of current to be supplied to the first and second electromagnetic coils 8 and 9 according to the combustion cycle of the engine and the load on the engine in consideration of the pressure in the combustion chamber. By using multiple maps with
Open / close control of the intake valve 1 and the exhaust valve 1 'is performed.

Here, the above-mentioned map will be described with reference to FIG. FIG. 3 schematically shows an example of a current waveform in which the amount of current supplied to the first and second electromagnetic coils 8 and 9 of the intake valve 1 and the exhaust valve 1 'is set. The vertical axis represents the amount of current, the horizontal axis represents the driving time of the valve element according to the engine speed, and the intake valve 1 is controlled based on the current waveform illustrated in the upper part, and the exhaust valve 1 is determined based on the current waveform illustrated in the lower part. Is driven. Further, in this current waveform, a driving current amount for attracting the plunger 7 to the electromagnetic coils 8 and 9 and a holding current amount for maintaining the open / closed state of the valve body are set, and the driving current amount according to the operating region of the engine is set. The setting of the holding current amount is changed.

According to the above map, the intake valve 1 indicated by the upper current waveform is supplied with the driving current amount A ₁ to the second electromagnetic coil 9 on the valve opening side for the time t ₁ to perform the valve opening operation. .
After t ₁ hour, until t ₂ hours holding current amount A ₂ is supplied open-valve state hold is performed. After the elapse of time t ₂ , the supply of current to the valve-opening second electromagnetic coil 9 is stopped to switch the intake valve 1 to the valve closing operation, and the valve-closing first electromagnetic coil 8 is closed until time t _3. performing the closing operation by supplying a drive current amount a ₃ in. After t ₃ hour, until t ₄ hours holding current amount A ₄ is supplied closed holding is performed. On the other hand, closing the holding is performed by holding the amount of current A ₅ to t ₄ hours to exhaust valve 1 'shown in the lower part of the current waveform supplied to the first electromagnetic coil 8 of the valve-closing side. The above times t ₁ , t ₂ , t
₃ and t ₄ are determined by a desired opening / closing timing according to the engine speed. In addition, a current waveform corresponding to the operating region of the engine is also set in the map. The low load region is indicated by a solid line, the middle load region is indicated by a broken line, and the high load region is indicated by a chain line.

Next, the contents of control relating to the driving of the intake valve 1 and the exhaust valve 1 'in this embodiment will be described with reference to the block diagram of the electromagnetically driven valve control device shown in FIG.

The electromagnetically driven valve control device is realized by a drive control circuit 50 as control means. In the drive control circuit 50, an intake valve 1 and an exhaust valve 1 'disposed in the internal combustion engine are excited when the valve is opened, and the second electromagnetic coil 9 which generates an electromagnetic force and when the valve is closed are excited. The first electromagnetic coil 8 that generates an electromagnetic force is connected via a control device 40 that controls the timing of generating the electromagnetic force according to the operation state. Also, a load sensor 5 4 for detecting a load L of the rotational speed sensor 5 3 and the engine for detecting a crank angle sensor 5 2 and the engine rotational speed NE for detecting a crank angle to detect the combustion cycle of the engine as a pressure detecting means From each sensor. Incidentally, the rotational speed sensor 5 3 crank angle sensor 5
It is not always necessary to calculate the engine speed from the detected value of 2 . The load sensor 5 4 is implemented by a throttle sensor for detecting an accelerator opening.

Here, the drive control circuit 50 detects from the crank angle sensor 52, the rotation speed sensor 53, and the load sensor 54, based on a plurality of maps showing current waveforms obtained experimentally in advance and stored in the ROM 51. An appropriate map based on the values is selected, and a current amount based on the current waveform of the selected map is supplied to the electromagnetic coils 8 of the intake valve 1 and the exhaust valve 1 '.
9, the opening / closing control is performed with a current amount corresponding to the pressure in the combustion chamber.

Next, a flowchart of an example of an electromagnetically driven valve control routine executed by the drive control circuit 50 to realize the above functions is shown. FIG. 4 shows a routine for driving the electromagnetically driven valve. When this routine is started, first, in step S1, the crank angle CA detected by the crank angle sensor 52 is read. Then, in step S2, it is specified whether the current combustion cycle of the engine based on the crank angle CA is in the intake, compression / combustion, or exhaust stroke state. Next, in step S3 and step S4,
It is determined whether the specified stroke is an intake stroke or compression / combustion. If the stroke is an intake stroke, a current amount supply process based on the map A (x) is performed in step S10. If it is the compression / combustion stroke, the map B is used in step S20.
A current supply process based on (x) is performed. If not, it is determined that the process is in the exhaust stroke, and step S3 is executed.
At 0, a current amount supply process based on the map C (x) is performed. Then, after completing steps S10, S20, and S30, the process returns to step S1. The maps A (x), B (x), and C (x) are specified by a current amount determination routine described below with reference to FIG. 5, and are extracted in the above steps S10, S20, and S30.

FIG. 5 shows a current amount determination routine. When this routine is started, first, in step S50, the engine speed NE detected by the engine speed sensor 53 is read. Next, in step S51, the engine load L detected from the load sensor 54 is read, and in step S52, the current engine operating region is any of the regions in FIG. 6 based on the engine speed NE and the load L. To identify. Then, in step S53, and step S54, whether a specified region which is (I) region, or (II) to determine an area, if (I) region, in each combustion cycle at step S60 (I) Map of area (A (I), B
(I), C (I)) are specified. If it is in the (II) region, in the step S70, (II) in each combustion cycle
An area map (A (II), B (II), C (II)) is specified. Also, if not either in each combustion cycle in step S80 it is determined that the (III) region (I
The map of the II) area (A (III), B (III), C (III)) is specified. The map above shows the combustion cycle as shown in FIG.
The amount of driving current and the amount of holding current to be supplied to the electromagnetic coils 8 and 9 of the intake valve 1 and the exhaust valve 1 'are set according to the operating range and the operating range. In FIG. 7, A (x), B (x), C
(X) indicates intake, compression / combustion, and exhaust strokes, respectively.
The inside of the parentheses indicates the operation area. Then, after ending the processing of steps S60, S70, and S80, the process returns to step S50.

As described above, the present engine combustion cycle is determined by the crank angle sensor 52, and the drive control circuit 50 determines the intake valves 1 and 2 based on the engine operating range detected by the rotation speed sensor 53 and the load sensor 54. A map showing a current waveform to be supplied to the electromagnetic coils 8 and 9 of the exhaust valve 1 'is selected, and a current amount based on the selected current waveform is supplied to the electromagnetic coils 8 and 9 so that each combustion cycle is performed. In each case, the valve opening or closing operation can be performed with the minimum amount of current using the pressure in the combustion chamber, and the amount of current consumption in opening and closing control of the intake valve 1 and the exhaust valve 1 ′ can be reduced.

[0039]

According to the present invention, since the holding current amount is changed based on the combustion cycle , it is possible to perform the valve closing holding control of the electromagnetically driven valve according to the pressure in the combustion chamber of the engine. The reduction in the amount of current can be improved.

[Brief description of the drawings]

FIG. 1 is a block diagram of an electromagnetically driven valve control device.

FIG. 2 is a sectional view of an electromagnetically driven valve according to the embodiment.

FIG. 3 is an example of a map showing a current waveform with respect to a drive time according to a supply current amount and an engine speed;

FIG. 4 is a flowchart of a driving routine of an electromagnetically driven valve in the embodiment.

FIG. 5 is a flowchart of a routine for determining a current amount of the electromagnetically driven valve in the embodiment.

FIG. 6 is a diagram showing an operating region of the engine in the embodiment.

FIG. 7 is a map showing a current waveform according to a supply current amount and an engine speed for each combustion cycle and operating region of the engine.

[Explanation of symbols]

 1. Electromagnetically driven valve (intake valve) 1 '.. Electromagnetically driven valve (exhaust valve) 8 ... first electromagnetic coil 9 ... second electromagnetic coil 50 .. drive control circuit 51 .. ROM 52 .. Crank angle sensor 53 ... Rotation speed sensor 54 ... Load sensor

Claims (1)

(57) [Claims] An electromagnetically driven valve for opening and closing a valve element disposed as an intake valve or an exhaust valve in an internal combustion engine by an electromagnetic force generated in an electromagnetic coil, and a timing of generation of the electromagnetic force generated in the electromagnetic coil by the engine. An electromagnetically driven valve control device having a control device that controls the engine in accordance with an operating state, wherein a crank angle sensor detects a current engine combustion cycle and an engine speed sensor and a load sensor detect an engine combustion cycle.
Detecting means for detecting an operating region; and an intake stroke if the detected combustion cycle is an intake stroke.
Process map, and the combustion cycle
The map for the compression / combustion process,
If the cycle is an exhaust stroke, select a map for the exhaust stroke
And among the current waveforms shown in the selected map,
If you select a current waveform based on the detected engine operating area,
In both cases, the valve is opened based on the selected current waveform.
Supplied to the electromagnetic coil to operate in the closing direction
The drive current amount and the electromagnetic force to maintain the valve body closed.
Set the amount of holding current supplied to the coil, and
Control means for controlling the electromagnetic coil by supplying the electromagnetic coil to the electromagnetic coil .