JP2985470B2 - Fuel injection timing control device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention is suitable for use in, for example, an electronically controlled diesel engine equipped with a fuel injection pump, and controls the duty of a timer control valve to drive a hydraulic timer to control the fuel injection pump. The present invention relates to a fuel injection timing control device that controls the fuel injection timing.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection pump of an electronically controlled diesel engine, a spill port is controlled by, for example, an electromagnetic spill valve or the like so that a fuel injection amount obtained according to a lift of a plunger thereof becomes a target value. I am trying to open it. Thereby, the fuel from the plunger high-pressure chamber overflows (spills), and the end of fuel pumping, that is, the end of fuel injection, is controlled, and the required fuel injection amount is controlled.

In such fuel injection amount control, usually, a target spill angle is converted into a time by a signal synchronized with the lift of the plunger and input at every constant pump rotation angle, for example, an engine rotation pulse and an average engine rotation speed. Then, the target spill time is determined, and the on / off control of the electromagnetic spill valve is performed based on the target spill time.

As for the control of the fuel injection timing, the fuel injection pump is provided with a hydraulic timer connected to a roller ring for lifting the plunger in engagement with a cam plate. The fuel injection timing is controlled by driving the timer piston by duty control of a timer control valve (TCV) to change the position of the timer piston.

As this type of duty control performed to control the fuel injection timing, for example, Japanese Patent Application Laid-Open No. 62-1
The technique disclosed in 53548 is known. According to the technique disclosed in this publication, in order to control the duty of the TCV, a basic duty ratio is calculated based on an engine speed and an accelerator opening, and a difference between a target ignition timing having a correlation with a timer piston position and an actual ignition timing is calculated. Each feedback correction term including the integral duty term and the proportional duty term is calculated based on the proportional integral control. Then, a final control duty ratio is determined by adding the integrated value of each feedback correction term to the basic duty ratio.

[0006]

However, in the above-mentioned prior art, in the fuel injection pump, the driving reaction force of the plunger acts on the timer piston via the cam plate and the roller ring. The driving reaction force of the plunger is a reaction force of fuel injection, and is larger as the fuel injection amount is larger, that is, as the load on the diesel engine is larger. When the load of the diesel engine changes, the driving reaction force of the plunger also changes. Therefore, it is necessary to change the control duty ratio to control the position of the timer piston. However, the feedback correction term for calculating the control duty ratio includes only the integral duty term and the proportional duty term corresponding to the timer piston position. That is, in the calculation of the control duty ratio, no correction reflecting the change in the driving reaction force of the plunger has been made.

Therefore, when the fuel injection amount changes suddenly and a change in the driving reaction force of the plunger acts on the timer piston, the control duty ratio is not corrected accordingly. Therefore, the timer piston position shifts to the retard side when the driving reaction force is large, and shifts to the advance side when the driving reaction force is small, and the responsiveness of the fuel injection timing control deteriorates by the deviation. There was a fear.

The present invention has been made in view of the above circumstances, and has as its object to provide a fuel injection timing control device capable of controlling fuel injection timing with good responsiveness in accordance with a change in the load of a diesel engine. Is to provide.

[0009]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, a plunger M3 reciprocally driven via a cam M2 in association with the rotation of a diesel engine M1. Pump M5 for injecting fuel into the diesel engine M1 by pressurizing the fuel in the high-pressure chamber M4, and the fuel injection pump M
5, a timer M7 having a timer piston M6 driven by control hydraulic pressure to change the reciprocating drive timing of the plunger M3 via the cam M2, and the control hydraulic pressure of the timer M7 is adjusted. A timer control valve M8 that is duty controlled to perform the operation, an operating state detecting means M9 for detecting the operating state of the diesel engine M1, and a required target injection timing determined based on the detection result of the operating state detecting means M9 In order to obtain the duty ratio, the duty ratio calculating means M10 for calculating the control duty ratio for controlling the duty of the timer control valve M8, and the control duty ratio calculated by the duty ratio calculating means M10 are determined by the target injection timing and the operating state detecting means M9. Feedback according to the deviation from the actual injection timing determined based on the detection result A feedback correction means M11 for correcting the positive value, the feedback correction means M11
And a duty control means M12 for duty-controlling the timer control valve M8 based on the final control duty ratio corrected by the following.
In order to determine the final control duty ratio, the control duty ratio calculated by the duty ratio calculation means M10 is corrected by the feedback correction value, and the fuel injection calculated based on the detection result of the operation state detection means M9. A load correction unit M13 is provided for performing correction based on the magnitude of the load equivalent value reflecting the amount.

[0010]

According to the above arrangement, as shown in FIG. 1, in the fuel injection pump M5, the plunger M3 is reciprocally driven via the cam M2 in association with the rotation of the diesel engine M1, whereby the high pressure chamber M4 is moved to the high pressure chamber M4. The fuel is pressurized and injected into the diesel engine M1. By this operation, the diesel engine M1 is operated.

The operating state detecting means M9 detects the operating state of the diesel engine M1 during operation. Further, the duty ratio calculating means M10 calculates a control duty ratio for performing duty control of the timer control valve M8 in order to obtain a required target injection timing determined based on the detection result of the operating state detecting means M9. Further, the feedback correction means M11 calculates the control duty ratio calculated by the duty ratio calculation means M10 in accordance with the deviation between the target injection timing and the actual injection timing based on the detection result of the operating state detection means M9. Correct by the correction value.

At the same time, the load correction means M13 corrects the control duty ratio calculated by the duty ratio calculation means M10 based on the feedback correction value in order to determine the final control duty ratio. correcting the magnitude of the independent load equivalent value reflecting the fuel injection amount obtained based on a detection result of means M9.

The duty control means M12 controls the duty of the timer control valve M8 based on the final control duty ratio corrected by the feedback correction means M11 and the load correction means M13. Thereby, the control oil pressure in the timer M7 is adjusted, the reciprocating drive timing of the plunger M3 is changed via the timer piston M6 and the cam M2, and the fuel injection timing from the fuel injection pump M5 is controlled.

Here, the reaction force of fuel injection from the high-pressure chamber M4 acts on the timer piston M6 via the cam M2 as the driving reaction force of the plunger M3, and the driving reaction force increases as the fuel injection amount increases. That is, the greater the load on the diesel engine, the greater. Therefore, the drive duty of the plunger M3 is reflected on the final control duty ratio by correcting the control duty ratio with the magnitude of the independent load equivalent value reflecting the fuel injection amount. Therefore, by controlling the timer control valve M8 based on the final control duty ratio, even when the load of the diesel engine M1 changes, the position of the timer piston M6 is changed according to the change in the driving reaction force of the plunger M3. Controlled.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the fuel injection timing control device according to the present invention is embodied in an automobile will be described in detail with reference to FIGS.

FIG. 2 is a schematic configuration diagram showing a fuel injection timing control device for a supercharged diesel engine in this embodiment, and FIG. 3 is a sectional view showing the distribution type fuel injection pump 1. The fuel injection pump 1 includes a drive pulley 3 which is drivingly connected to a crankshaft 40 of the diesel engine 2 via a belt or the like. The fuel injection pump 1 is driven by the rotation of the drive pulley 3, and the fuel is injected under pressure to each fuel injection nozzle 4 provided for each cylinder (four cylinders in this case) of the diesel engine 2 to perform fuel injection. .

In the fuel injection pump 1, the drive pulley 3 is attached to a tip of a drive shaft 5.
In the middle of the drive shaft 5, there is provided a fuel feed pump (developed at 90 degrees in this figure) 6 composed of a vane type pump. Further, a disk-shaped pulser 7 is attached to the base end side of the drive shaft 5. The outer surface of the pulsar 7 has a diesel engine 2
In this case, four cutting teeth are formed at equal angular intervals, that is, four cutting teeth are formed at equal angular intervals between each cutting tooth. I have. The base end of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown).

A roller ring 9 is provided between the pulsar 7 and the cam plate 8, and a plurality of cam rollers 10 facing the cam face 8a of the cam plate 8 are mounted along the circumference of the roller ring 9. I have. Cam face 8
a is provided as many as the number of cylinders of the diesel engine 2. The cam plate 8 is always urged and engaged with the cam roller 10 by the spring 11.

A base end of a fuel pressurizing plunger 12 is attached to the cam plate 8 so as to be integrally rotatable, and the cam plate 8 and the plunger 12 are rotated in conjunction with the rotation of the drive shaft 5. That is, the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via a coupling (not shown), so that the cam plate 8 rotates and engages with the cam roller 10 to rotate in the left-right direction by the same number as the number of cylinders. Is reciprocated. Further, the plunger 12 is driven to reciprocate in the same direction while rotating with the reciprocation. That is, the plunger 12 is moved forward (lift) while the cam face 8a of the cam plate 8 rides on the cam roller 10 of the roller ring 9, and conversely, the plunger 1 is moved while the cam face 8a rides down the cam roller 10.
2 is reactivated.

The plunger 12 is fitted into a cylinder 14 formed in the pump housing 13, and a high pressure chamber 15 is formed between the tip of the plunger 12 and the bottom of the cylinder 14.
It has become. Also, on the outer periphery of the tip side of the plunger 12,
The same number of intake grooves 16 and distribution ports 17 as the number of cylinders of the diesel engine 2 are formed. In addition, these suction grooves 16
And the pump housing 13 corresponding to the distribution port 17.
Is formed with a distribution passage 18 and a suction port 19.

When the drive shaft 5 is rotated and the fuel feed pump 6 is driven, fuel is supplied from a fuel tank (not shown) into the fuel chamber 21 via the fuel supply port 20. Also, during the suction stroke in which the plunger 12 is moved back and the high-pressure chamber 15 is depressurized, the suction groove 1
The fuel is introduced from the fuel chamber 21 to the high-pressure chamber 15 when one of the ports 6 communicates with the suction port 19. On the other hand, during the compression stroke in which the plunger 12 is moved forward and the high-pressure chamber 15 is pressurized, fuel is pressure-fed from the distribution passage 18 to the fuel injection nozzle 4 of each cylinder and injected.

The pump housing 13 is provided with a spill passage 22 for fuel spill that connects the high-pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 as a spill adjusting valve for adjusting the fuel spill from the high-pressure chamber 15 is provided in the middle of the spill passage 22. The electromagnetic spill valve 23 is a normally open type valve. When the coil 24 is not energized (off), the valve body 25 is opened and fuel in the high-pressure chamber 15 is spilled to the fuel chamber 21. When the coil 24 is energized (turned on), the valve body 25 is closed, and the spill of fuel from the high-pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by controlling the energization time of the electromagnetic spill valve 23, the valve 23 is controlled to close and open, and the spill amount of fuel from the high-pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel in the high-pressure chamber 15 is reduced in pressure, and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even when the plunger 12 moves forward, the fuel pressure in the high-pressure chamber 15 does not increase while the electromagnetic spill valve 23 is open, and the fuel injection from the fuel injection nozzle 4 is not performed. Further, during the forward movement of the plunger 12, by controlling the timing of closing and opening the electromagnetic spill valve 23, the amount of fuel injected from the fuel injection nozzle 4 is controlled.

Below the pump housing 13, there is provided a timer device (deployed 90 degrees in this figure) 26 for controlling the fuel injection timing. The timer device 26 changes the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5, thereby changing the timing at which the cam face 8a engages with the cam roller 10, that is, the reciprocating drive timing of the cam plate 8 and the plunger 12. It is for.

The timer device 26 is driven by control hydraulic pressure, and includes a timer housing 27, a timer piston 28 fitted in the housing 27, and a timer A timer spring 31 for urging the piston 28 toward the other pressurizing chamber 30 is provided. The timer piston 28 is connected to the roller ring 9 via a slide pin 32.

In the pressurizing chamber 30 of the timer housing 27,
The fuel pressurized by the fuel feed pump 6 is introduced. The position of the timer piston 28 (hereinafter, referred to as “timer piston position”) is determined based on the balance between the fuel pressure and the urging force of the timer spring 31. Further, by determining the timer piston position, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

The timer device 26 is provided with a timer control valve (TCV) 33 for adjusting the fuel pressure acting as the control oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27
4 and the TC in the middle of the communication passage 34.
V33 is provided. The TCV 33 is an electromagnetic valve whose opening and closing are controlled by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by controlling the opening and closing of the TCV 33. Then, by adjusting the fuel pressure, the lift timing of the plunger 12 is controlled, and the fuel injection timing from each fuel injection nozzle 4 is controlled.

On the upper part of the roller ring 9, a rotation speed sensor 35 composed of an electromagnetic pickup coil is mounted so as to face the outer peripheral surface of the pulser 7. This rotation speed sensor 35
Detects the passage of a projection or the like of the pulsar 7 when they cross, and outputs a timing signal (engine rotation pulse) corresponding to the engine speed NE. Further, since the rotation speed sensor 35 is integrated with the roller ring 9, the rotation speed sensor 35 outputs a reference timing signal to the plunger lift at a constant timing regardless of the control operation of the timer device 26.

Next, the diesel engine 2 will be described. In the diesel engine 2, a main combustion chamber 44 corresponding to each cylinder is formed by the cylinder 41, the piston 42, and the cylinder head 43. or,
A sub-combustion chamber 45 communicating with each of the main combustion chambers 44 is provided for each cylinder. And each sub-combustion chamber 45
Is supplied with fuel injected from each fuel injection nozzle 4. Further, a well-known glow plug 46 as a start-up assist device is attached to each sub-combustion chamber 45.

The diesel engine 2 is provided with an intake pipe 47 and an exhaust pipe 48. The intake pipe 47 is provided with a compressor 50 of a turbocharger 49 constituting a supercharger, and the exhaust pipe 48 is provided with a turbocharger. 49
Turbine 51 is provided. The exhaust pipe 48 has a waste gate valve 5 for adjusting the supercharging pressure PiM.
2 are provided. As is well known, the turbocharger 49 uses the energy of the exhaust gas to rotate the turbine 51, and rotates the compressor 50 on the same axis as the turbine 51 to increase the pressure of the intake air. By this operation, a mixture of high density is sent to the main combustion chamber 44 to burn a large amount of fuel, thereby increasing the output of the diesel engine 2.

The diesel engine 2 has an exhaust pipe 4
A recirculation pipe 54 for recirculating a part of the exhaust gas in 8 to the suction port 53 of the intake pipe 47 is provided. An exhaust gas recirculation valve (EGR valve) 55 for adjusting the amount of exhaust gas recirculation is provided in the middle of the recirculation pipe 54. The opening and closing of the EGR valve 55 is controlled by the control of a vacuum switching valve (VSV) 56.

Further, a throttle valve 58 that opens and closes in conjunction with the depression amount of an accelerator pedal 57 is provided in the middle of the intake pipe 47. Also, its throttle valve 5
A bypass passage 59 is provided in parallel with 8, and a bypass throttle valve 60 is provided in the bypass passage 59. The opening and closing of the bypass throttle valve 60 is controlled by an actuator 63 having a two-stage diaphragm chamber driven by control of two VSVs 61 and 62. The opening and closing of the bypass throttle valve 60 is controlled in accordance with various operation states. For example, it is controlled to a half-open state during idle operation to reduce noise and vibration, to a fully opened state during normal operation, and to a fully closed state during smooth operation to stop smoothly.

The electromagnetic spill valve 2 provided in the fuel injection pump 1 and the diesel engine 2 as described above
3, TCV33, glow plug 46 and each VSV56,
Numerals 61 and 62 are electrically connected to electronic control units (hereinafter simply referred to as “ECUs”) 71 constituting duty ratio calculation means, feedback correction means, duty control means and load correction means, respectively. Timing is controlled.

As sensors constituting the operating state detecting means of the diesel engine 2, the following various sensors are provided in addition to the rotation speed sensor 35. That is, the intake pipe 47
An intake air temperature sensor 72 for detecting an intake air temperature THA is provided near an air cleaner 64 provided at an inlet of the air conditioner. Further, the accelerator opening ACCP corresponding to the load of the diesel engine 2 is determined based on the open / close position of the throttle valve 58.
Is provided with an accelerator opening sensor 73 for detecting the acceleration.
An intake pressure sensor 74 that detects the intake air pressure after supercharging by the turbocharger 49, that is, the supercharging pressure PiM is provided near the intake port 53. Further, a water temperature sensor 75 for detecting the cooling water temperature THW of the diesel engine 2 is provided. Further, a crank angle sensor 76 for detecting a rotation reference position of the crankshaft 40, for example, a rotation position of the crankshaft 40 with respect to a top dead center of a specific cylinder is provided. Further, a transmission (not shown) has a magnet 77a which is turned by rotation of the gear.
A vehicle speed sensor 77 for turning on / off the reed switch 77b to detect the vehicle speed (vehicle speed) SP is provided.

The ECU 71 is connected to the sensors 72 to 77 described above, respectively,
5 is connected. In addition, the ECU 71 controls each sensor 35,
Based on the detection signals output from 72 to 77, the electromagnetic spill valve 23, the TCV 33, the glow plug 46, and the VSV 5
6, 61, 62, etc. are suitably controlled.

Next, the configuration of the ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 has a central processing unit (CPU) 81, a read-only memory (RO) storing a predetermined control program, a map, and the like in advance.
M) 82, a random access memory (RAM) 83 for temporarily storing the operation results and the like of the CPU 81, a backup RAM 84 for storing previously stored data, and the like, and a bus 87 for connecting these components to the input port 85 and the output port 86.
Are configured as logical operation circuits connected with each other.

The input port 85 is provided with the above-described intake air temperature sensor 72, accelerator opening sensor 73, intake pressure sensor 74, and water temperature sensor 75 in buffers 88, 89, 90, and 9, respectively.
1, a multiplexer 93 and an A / D converter 94. Similarly, the input port 85 is connected to the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 via a waveform shaping circuit 95. Then, the CPU 81 reads, as input values, detection signals of the sensors 35, 72 to 77, etc., which are input through the input port 85. Each drive circuit 9 is connected to the output port 86.
6, 97, 98, 99, 100, 101, the electromagnetic spill valve 23, the TCV 33, the glow plug 46 and the VSV.
56, 61, 62, etc. are connected.

Then, the CPU 81 controls each of the sensors 35 and 72.
Based on the input value read from ~ 77, the electromagnetic spill valve 2
3, TCV33, glow plug 46 and VSV56,6
1, 62, etc. are suitably controlled.

Next, the processing operation of the fuel injection timing control executed by the ECU 71 will be described with reference to FIGS. First, the flowchart shown in FIG.
Among the processes executed by the CU 71, in order to adjust the control oil pressure in the timer device 26 of the fuel injection pump 1,
This is a processing routine for calculating an on-duty time FSDUTY for duty control of the TCV 33, and is executed at every interruption of an engine rotation pulse from the rotation speed sensor 35.

When the process proceeds to this routine, first, at step 101, the engine speed NE is read based on the detection value of the speed sensor 35. Subsequently, in step 102, based on the engine rotation pulse obtained from the detection value of the rotation speed sensor 35, the interruption pulse counter CNIRQ of the engine rotation speed NE adds "1" to the spill reference pulse number CANGL corresponding to the injection end timing. It is determined whether or not the number of pulses has reached. That is, it is determined whether the fuel injection has been completely completed. For example, as shown in FIG. 6, when the spill reference pulse number CANGL is "4", the value of the interrupt pulse counter CNIRQ for completely terminating the fuel injection is "5".

If the fuel injection has not been completely completed, the subsequent processing is temporarily terminated. or,
If the fuel injection is completely completed, the next step 10
Move to 3.

Then, in step 103, TC
It is determined whether or not an on / off switching counter CTCV for instructing on / off switching of V33 is “0”. The on / off switching counter CTCV is set in step 107, which will be described later, according to the magnitude of the engine speed NE.

Here, the on / off switching counter CTCV
Is not "0", in step 104, a result obtained by subtracting "1" from the value of the on / off switching counter CTCV is set as a new value of the on / off switching counter CTCV, and the subsequent processing is temporarily terminated. I do.

On the other hand, if the on / off switching counter CTCV is "0" in step 103, the TCV 33 is turned on and opened in step 105. or,
In step 106, as shown in FIG.
The ON time TON of No. 3 is set.

Subsequently, at step 107, the value of the above-mentioned on / off switching counter CTCV is set according to the magnitude of the engine speed NE. That is, if the engine speed NE is less than "1200 rpm", the value of the on / off switching counter CTCV is set to "1", and the engine speed NE is equal to or more than "1200 rpm" and less than "2400 rpm". In this case, the value of the on / off switching counter CTCV is set to “2”, and when the engine speed NE is “2400 rpm” or more, the value of the on / off switching counter CTCV is set to “4”. .

Therefore, the on / off switching counter CTCV
Is set to "1", for example, as shown in FIG. 7, the ON time TON is set every time fuel injection is completed once and the "CANGL + 1" th engine rotation pulse is input and started. . When the on / off switching counter CTCV is set to “2”, the fuel injection is completed twice, and the “ONGL + 1” th engine rotation pulse immediately thereafter is input and the ON time TON is increased every time the engine starts. Set. Further, when the on / off switching counter CTCV is set to "4", the fuel injection is completed four times, and immediately after that, the "CANGL + 1" th engine rotation pulse is inputted and the on time T is increased.
ON is set.

That is, the TCV 33 is opened during the non-injection period after the end of the fuel injection to minimize the deviation of the spill timing due to the reaction force of the roller ring 9. However, if the TCV 33 is driven each time fuel injection is completed once, the drive frequency of the TCV 33 increases in accordance with the increase in the engine speed NE.
The drive frequency of 33 is too high, which is not preferable in terms of reliability. Therefore, according to the increase in the engine speed NE, the TCV
The drive frequency of the TCV 33 is changed by changing the valve opening of the valve 33 after the fuel injection is completed two times and further after the fuel injection is completed four times, so that the drive frequency is maintained in an appropriate range. In this embodiment, the driving frequency of the TCV 33 is 4
In the case of a four-cylinder engine, the on / off switching counter CTCV changes from “1” to “2” or “2” to “1” and further from “2” to “4” according to the magnitude of the engine speed NE. Or, when it changes from “4” to “2”, it switches from “40 Hz” to “20 Hz” or “20 Hz” to “40 Hz”, respectively.

Then, at step 108, the TCV
In order to control the duty of 33, an on-duty time FSDUTY as shown in FIG. 7 is calculated. The on-duty time FSDUTY is obtained according to a predetermined formula using a target on-duty ratio FTDUTY or the like as a control duty ratio separately obtained as a base value. When the calculation of the on-duty time FSDUTY is completed, the subsequent processing is temporarily terminated.

Here, in step 108, the target on-duty ratio FTDUTY used for calculating the on-duty time FSDUTY is obtained according to the flowchart shown in FIG. This flowchart is based on the ECU 7
1 is a processing routine executed by a periodic interruption every 49 ms.

That is, first, in step 201, the engine speed NE is determined based on the value detected by the speed sensor 35.
Read. At the same time, in a separate processing routine,
The final injection amount QFIN is read as a target injection amount command value obtained by using the accelerator opening ACCP and the engine speed NE as parameters.

Subsequently, at step 202, the read engine speed NE and final injection amount QFIN are read.
, The rotation correction injection amount QF according to the following formula:
INS, that is, the injection amount corrected according to the engine speed NE is calculated.

QFINS = QFIN− (100−0.05 * NE) Next, at step 203, the previously read engine speed NE and the calculated rotation correction injection amount QFIN
In S, a target crank angle timing TRGCA as a target injection timing command value is calculated with reference to a predetermined two-dimensional map (not shown). Further, in step 204, the actual crank angle timing ACTCA as the actual injection timing obtained in a separate processing routine is read. Then, in step 205, the deviation Δ between the target crank angle timing TRGCA and the actual crank angle timing ACTCA is calculated.
T, that is, the deviation of the injection timing is calculated.

Subsequently, in step 206, based on the calculated deviation ΔT, referring to a predetermined map as shown in FIG.
An integral correction term ΔTDUTYI is calculated as a feedback correction value for obtaining UTY. At the same time, in step 207, a proportional correction term TDUTYP as a feedback correction value for obtaining the target on-duty ratio FTDUTY is calculated with reference to a predetermined map as shown in FIG. .

Further, in step 208, the load correction as a load equivalent value reflecting the fuel injection amount is made by referring to the predetermined map as shown in FIG. 11 based on the rotation correction injection amount QFINS previously obtained. The term TDUTYO is calculated. That is, the load correction term TDUT for reflecting the difference in the fuel injection amount in the target on-duty ratio FTDUTY.
You want YO. As is clear from this map, the load correction term TDUYO is the rotation correction injection amount QFIN.
The injection timing is set so as to decrease as S increases, that is, to advance the injection timing.

Subsequently, in step 209, the target on-duty ratio FTDUTY in the previous control cycle is set.
The target on-duty ratio FTDUTY in the current control cycle is calculated by adding or subtracting the integral correction term ΔTDUTYI and the proportional correction term TDUTYP to (i−1), respectively, and adding the load correction term TDUTYO. That is, in calculating the current target on-duty ratio FTDUTY, the previous target on-duty ratio FTDUT is used.
In addition to correcting Y (i-1) using an integral correction term ΔTDUTYI and a proportional correction term TDUTYP as feedback correction values, an independent load correction term T reflecting a fuel injection amount is used.
It is corrected by DUTYO.

In step 210, the current target on-duty ratio FTDUTY is set as the previous target on-duty ratio FTDUTY (i-1), and the subsequent processing is temporarily terminated.

The target on-duty ratio FTDUTY obtained in this way is the same as the target crank angle timing TRGC.
This is a value constituting a duty ratio command value for A. Then, in step 108 of the flowchart shown in FIG. 5, an on-duty time FSDUTY for duty-controlling the TCV 33 is calculated from the target on-duty ratio FTDUTY or the like according to a predetermined calculation formula.

On the other hand, as shown in FIG. 7, the OFF time TOFF for turning off the TCV 33 is set according to the flowchart shown in FIG. This flowchart is a processing routine executed by the ECU 71,
It is executed by interruption every time the ON time TON of the TCV 33 is set.

That is, first, at step 301, the current time TN is read. Subsequently, in step 302, the on-duty time F is set at the current time TN.
The result of adding SDUTY is set as the off time TOFF. Then, in step 303, when the off time TOFF arrives, the TCV 33 is turned off and closed.

According to the above-described processing, the ON time TON of the TCV 33 is determined according to the engine speed NE at each time.
And OFF time TOFF are set, respectively, and TCV33
Is duty controlled. Thereby, the timer device 26
Is adjusted to control the position of the timer piston 28, the reciprocating drive timing of the plunger 12 is changed via the slide pin 32, the roller ring 9 and the cam plate 8, and the fuel injection timing from the fuel injection pump 1 is changed. Controlled.

As described above, according to the fuel injection timing control device of this embodiment, when calculating the target on-duty ratio FTDUTY used for duty control of the TCV 33, the previous target on-duty ratio FTDUT is used.
Y (i-1) is set to an integral correction term ΔTDUT as a feedback correction value obtained according to a deviation ΔT between the target crank angle timing TRGCA and the actual crank angle timing ACTCA.
YI and the proportional correction term TDUTYP are used, and the load correction term TDUUT is independent by reflecting the fuel injection amount.
It is corrected by YO. That is, in order to determine the target on-duty ratio FTDUTY, feedback correction is independently performed based on the deviation ΔT between the target injection timing and the actual injection timing, and the amount of fuel injection that affects the driving reaction force of the plunger 12 is increased. Independent corrections are made accordingly.

Here, in the fuel injection pump 1, generally, the driving reaction force of the plunger 12 generates the timer piston 28 via the cam plate 8, the roller ring 9 and the slide pin 32.
Act on. In addition, the driving reaction force is a fuel injection reaction force, which increases as the fuel injection amount, that is, the load on the diesel engine 2 increases.

However, in this embodiment, as described above, since the correction based on the load correction term TDUTYO reflecting the fuel injection amount is performed, the driving reaction force of the plunger 12 is changed to the final target on-duty ratio FTDUTY. Will be reflected. Therefore, at the moment when the fuel injection amount changes suddenly due to rapid acceleration / deceleration, for example, and the change in the driving reaction force of the plunger 12 acts on the timer piston 28, the target on-duty corresponding to the change in the driving reaction force Ratio FTDUT
Y can be corrected.

FIG. 13 shows the vehicle speed SP and the final injection amount QF.
6 is a time chart for explaining a correspondence relationship between IN, actual crank angle timing ACTCA, target crank angle timing TRGCA, and target on-duty ratio FTDUTY. In this time chart, it is assumed that the deceleration is performed at time t1 and the final injection amount QFIN is rapidly reduced. In this case, although the actual crank angle timing ACTCA does not change immediately, the target on-duty ratio FTDUTY of the present embodiment shown by the solid line is different from that of the conventional example shown by the two-dot chain line and immediately follows without changing with a delay. Will change.

Therefore, the duty control of the TCV 33 is performed based on the target on-duty ratio FTDUTY thus corrected, so that the drive reaction force of the plunger 12 is changed and the influence of the drive reaction force is eliminated. Immediately, the position of the timer piston 28 can be appropriately controlled. As a result, control of the fuel injection timing can be executed with good responsiveness in accordance with the load change of the diesel engine 2. That is, it is possible to improve the followability of the fuel injection timing control at the time of load change, and to prevent the fuel injection timing from the fuel injection pump 1 from being advanced or delayed. Therefore, it is possible to improve the exhaust emission of the diesel engine 2 and the drivability of the vehicle.

In addition, in this embodiment, in order to correct and calculate the target on-duty ratio FTDUTY, an integral correction term ΔTDUTYI and a proportional correction term TDUTYP as feedback correction values, and a load correction term TDUYO reflecting the fuel injection amount are used. Are required independently of each other. Therefore, unlike feedback control of the fuel injection timing including load fluctuation reflecting the fuel injection amount, feedback control of the optimal fuel injection timing with high accuracy can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, and may be carried out as follows by appropriately changing a part of the configuration without departing from the spirit of the invention. (1) In the above embodiment, the target on-duty ratio FTDU
The load correction term TDUTYO obtained by the rotation correction injection amount QFINS was used as the load equivalent value reflecting the fuel injection amount to calculate the correction TY. If the value reflects the fuel injection amount, for example, the accelerator opening A correction term determined according to ACCP can also be used.

(2) In the above embodiment, the diesel engine 2 provided with the turbocharger 49 as the supercharger is embodied. However, the diesel engine provided with the supercharger as the supercharger or the supercharger is provided. Not embodied in diesel engines.

[0069]

As described above in detail, according to the present invention, the timer piston of the hydraulic timer is driven by the duty-controlled timer control valve to change the reciprocating drive timing of the plunger so that the fuel injection pump can be controlled. When controlling the fuel injection timing, the control duty ratio calculated for duty-controlling the timer control valve to obtain the required target injection timing determined according to the operation state of the diesel engine is determined by the target injection timing and the actual duty ratio. In addition to the correction by the feedback correction value according to the deviation from the injection timing, the final control duty ratio is corrected by correcting the magnitude of the independent load equivalent value reflecting the fuel injection amount obtained according to the operating state. Since the fuel injection amount changes when the load on the diesel engine changes, the plunger Timer piston position according to the change of the dynamic reaction force is controlled, there is exhibited an excellent effect that the control of the fuel injection timing can be performed with good response according to the load variation of the diesel engine.

[Brief description of the drawings]

FIG. 1 is a conceptual configuration diagram illustrating a basic conceptual configuration of the present invention.

2 is a schematic configuration diagram showing a fuel injection timing control device for a supercharger <br/> with diesel engines in an embodiment embodying the present invention.

FIG. 3 is a cross-sectional view illustrating a distribution type fuel injection pump according to one embodiment.

FIG. 4 is a block diagram illustrating a configuration of an ECU according to one embodiment.

FIG. 5 is a flow chart illustrating a process executed by an ECU according to an embodiment;
9 is a flowchart illustrating a processing routine executed by an interrupt for each input of an engine rotation pulse for calculating an on-duty time of V.

FIG. 6 is a time chart illustrating a correspondence relationship between an engine rotation pulse, opening and closing of an electromagnetic spill valve, and a plunger lift in one embodiment.

FIG. 7 shows an engine rotation pulse and TCV in one embodiment.
5 is a time chart for explaining a correspondence relationship between on / off driving.

FIG. 8 is a flow chart illustrating a process executed by an ECU according to an embodiment of the present invention;
It is a flowchart explaining the processing routine performed by the periodic interruption for every 49 ms for calculation of the target on-duty time of V.

FIG. 9 is a map in which a relationship between an integral correction term and a deviation between a target crank angle timing and an actual crank angle timing is determined in one embodiment.

FIG. 10 is a map in which a relationship between a proportional correction term and a deviation between a target crank angle timing and an actual crank angle timing is determined in one embodiment.

FIG. 11 is a map in which a relationship between a rotation correction injection amount and a load correction term in one embodiment is determined in advance.

FIG. 12 is a flowchart illustrating an operation executed by the ECU according to the embodiment;
It is a flowchart explaining the processing routine performed by interruption for every TCV ON time set for OFF time setting of CV.

FIG. 13 is a time chart illustrating a correspondence relationship among a vehicle speed, a final injection amount, an actual crank angle timing, a target crank angle timing, and a target on-duty ratio in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 2 ... Diesel engine, 8 ... Cam plate, 9 ... Roller ring, 12 ... Plunger, 1
5 High-pressure chamber, 26 Timer device, 28 Timer piston, 33 Timer control valve (TCV), 35 Speed sensor, 73 Accelerator opening sensor (35 and 73 constitute operating state detecting means) ), 71: ECUs constituting duty ratio calculation means, feedback correction means, duty control means and load correction means.

Claims (1)

(57) [Claims] 1. A fuel injection pump for injecting fuel into a diesel engine by pressurizing fuel in a high-pressure chamber by a plunger reciprocally driven via a cam in conjunction with rotation of the diesel engine, and the fuel injection pump. To control the fuel injection timing from
A timer having a timer piston driven by control hydraulic pressure for changing the reciprocating drive timing of the plunger via the cam; a timer control valve duty-controlled to adjust control hydraulic pressure in the timer; and the diesel Operating state detecting means for detecting an operating state of the engine, and a control duty ratio for duty controlling the timer control valve to obtain a required target injection timing determined based on a detection result of the operating state detecting means. A duty ratio calculating means for calculating, and a control duty ratio calculated by the duty ratio calculating means according to a deviation between the target injection timing and an actual injection timing obtained based on a detection result of the operating state detecting means. Feedback correction means for correcting with a feedback correction value; A duty control means for duty-controlling the timer control valve based on the final control duty ratio corrected by the correction means.In the fuel injection timing control device, in order to determine the final control duty ratio, In addition to correcting the control duty ratio calculated by the duty ratio calculation means with the feedback correction value,
A fuel injection timing control device, comprising: load correction means for correcting by a magnitude of a load equivalent value reflecting a fuel injection amount obtained based on a detection result of the operation state detection means.