JP3052647B2 - Fuel injection control device for high pressure injection 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 a high-pressure injection internal combustion engine having a fuel injection pump, a fuel injection nozzle, and the like. The present invention relates to a control device.

[0002]

2. Description of the Related Art Hitherto, as a high-pressure injection internal combustion engine provided with a fuel injection pump, a fuel injection nozzle, and the like, a diesel engine, a high-pressure gasoline injection engine, and the like are given.
In this high-pressure injection internal combustion engine, fuel injection control is performed so that the amount of fuel injected from the fuel injection nozzle and the fuel injection timing match the target values.

For example, in an electronically controlled diesel engine, the fuel in a high-pressure chamber is pressure-fed to a fuel injection nozzle and injected into each cylinder of the engine by a lift of a plunger in a fuel injection pump. Then, the spill ring, the spill valve, and the like provided in the fuel injection pump are driven and controlled by the actuator such that the fuel injection amount at that time becomes the target injection amount determined according to the operation state of the engine. By this control, the plunger high-pressure chamber is opened to the fuel chamber, and a part of the fuel in the plunger high-pressure chamber overflows (spills) to the fuel chamber. Thus, the end of the fuel pumping from the fuel injection pump to the fuel injection nozzle, that is, the end timing of the fuel injection from the fuel injection nozzle to each cylinder is controlled.

However, even in an electronically controlled diesel engine in which the above-described fuel injection amount control is performed,
The fuel injection nozzle is generally a mere mechanical automatic valve. Further, since the fuel injection nozzle is a mechanical automatic valve, there is a possibility that the actual fuel injection amount from the nozzle may change due to the temporal decrease of the valve opening pressure. That is, this type of fuel injection nozzle includes a needle valve and a spring for adjusting the valve opening pressure of the needle valve, and is opened by obtaining a fuel pressure equal to or higher than a predetermined level. Further, the valve opening pressure of the needle valve is adjusted in advance to a constant value by a spring. Then, when the force of the spring becomes weaker due to a change over time, the valve opening pressure of the needle valve becomes smaller than the set pressure initially set. Therefore, in that case, the fuel injection amount from the fuel injection nozzle deviates from the intended target injection amount, and there is a possibility that smoke and nitrogen oxide (NOx) emissions from the engine may increase. .

[0005] Therefore, a technique for addressing the above-mentioned inconvenience was not known at the time of this application, but was filed in the present application.
Japanese Patent Application No. 4-223084 and Japanese Patent Application No.
And drawings. According to this conventional technique, it is possible to stably perform high-precision fuel injection amount control by coping with a change in valve opening pressure caused by a change over time or a manufacturing error without providing a special pressure adjusting means in a fuel injection nozzle. Is aimed at. Therefore, in this prior art, at the start of fuel injection, the valve opening pressure at the time of opening the fuel injection nozzle is measured, and the difference between the measured valve opening pressure and a predetermined reference pressure is defined as a valve opening pressure deviation. Desired. Further, based on the valve opening pressure deviation, the amount of change in the amount of residual fuel in the fuel system from the fuel injection pump to the fuel injection nozzle is determined. Then, the target injection amount for the next fuel injection is corrected based on the change amount of the residual fuel amount. This was done by focusing on the fact that the difference in the valve opening pressure of the fuel injection nozzle correlates with the amount of change in the residual fuel amount in the fuel system. This is supported by the fact that the fuel injection amount from the injection nozzle is changed. Here, the fuel injection amount is corrected based on the amount of change in the residual fuel amount only in the low engine speed range.

[0006]

However, in the above prior art, the valve opening pressure at the time of opening the fuel injection nozzle is used to determine the amount of change in the amount of residual fuel in the fuel system. Here, although the difference in the valve opening pressure has some correlation with the difference in the amount of change in the residual fuel amount,
The amount of change in the residual fuel amount did not directly change due to the difference in the valve opening pressure. Therefore, in order to ensure the required accuracy in correcting the fuel injection amount, the correction must be performed only in the low rotation speed range of the engine. Then, in the high rotation region other than the low rotation region, the amount of change in the residual fuel amount cannot be accurately obtained by the valve opening pressure, and there is a problem in the accuracy of the fuel injection amount correction. In addition, particularly in a direct injection type diesel engine, since the fuel injection nozzle has a structure that increases the injection rate, an error is large even if an attempt is made to obtain the amount of change in the remaining fuel amount from the difference in valve opening pressure. There was a risk of becoming.

The present invention has been made in view of the above-mentioned circumstances, and has been made in view of the fact that the residual fuel amount changes with a stronger correlation with the valve closing pressure than the valve opening pressure of the fuel injection nozzle. It is. And the purpose is
High-pressure injection internal combustion that can accurately determine the difference in the residual fuel amount in the fuel system and perform more accurate fuel injection control regardless of the rotation range of the internal combustion engine or whether or not it is a direct injection type An object of the present invention is to provide a fuel injection control device for an engine.

[0008]

In order to achieve the above object, according to the first aspect of the present invention, a fuel injection pump is provided.
Internal combustion pumping fuel from the fuel to the fuel injection nozzle
Which is used in the engine, detecting means for detecting a fuel pressure at the time of closing of the fuel injection nozzle as closing pressure, based on the detection result of the detecting means, the fuel injection
In the fuel system from the injection pump to the fuel injection nozzle
Distilling control amount for the fuel amount of fuel injection reflecting the computed, and control means for driving and controlling the fuel injection pump based on the calculation result. Here, FIG. 1 shows a conceptual configuration of one embodiment for suitably implementing the present invention.
That is, in the example shown in the figure, a valve is opened by obtaining a fuel pressure equal to or higher than a predetermined level, and a fuel injection nozzle M2 for injecting fuel into the high-pressure injection internal combustion engine M1, and fuel is fed to the fuel injection nozzle M2 by pressure. A fuel injection pump M3, which is driven and controlled, a fuel pressure detecting means M4 for detecting the fuel pressure when the fuel injection nozzle M2 is closed as a valve closing pressure, and the fuel pressure detecting means M4 detects the fuel pressure. A residual fuel amount calculating means M6 for calculating a residual fuel amount in the fuel system M5 from the fuel injection pump M3 to the fuel injection nozzle M2 based on the valve closing pressure;
A residual fuel amount deviation calculating means M7 for calculating the difference between the reference residual fuel amount and the residual fuel amount calculated by the residual fuel amount calculating means M6 when the valve is closed as a residual fuel amount deviation; A control amount correction unit M8 for correcting various control amounts for fuel injection based on the calculation result of the fuel amount deviation calculation unit M7, and a fuel injection pump M3 is driven based on the correction result of the control amount correction unit M8. And a pump control means M9 for control. This configuration corresponds to the second aspect of the invention.
I have.

[0009]

[Function] Fuel from the fuel injection pump to the fuel injection nozzle
The amount of fuel remaining in the system depends on the amount of fuel
It is known that it affects the firing timing and the like. I
Therefore, as in the configuration of claim 1, the residual
Detect valve closing pressure that has a strong correlation with fuel quantity
Then, based on the detection result, the fuel
Calculates the amount of residual fuel in the fuel system up to the fuel injection nozzle
By doing so, it is possible to control the fuel injection amount accurately. Ma
According to the configuration of claim 2 , as shown in FIG.
Then, when the fuel is pumped from the fuel injection pump M3 to the fuel injection nozzle M2 and the fuel injection is performed, the fuel pressure detection means M4 detects the valve closing pressure when the fuel injection nozzle M2 is closed. The residual fuel amount calculating means M6 calculates the residual fuel amount in the fuel system M5 based on the valve closing pressure. Further, in the residual fuel amount deviation calculating means M7, the difference between the reference residual fuel amount at the time of closing the valve and the actually calculated residual fuel amount is calculated as the residual fuel amount deviation. The control amount correction means M8 corrects various control amounts for fuel injection, for example, the fuel injection amount and the fuel injection timing, based on the calculated residual fuel amount deviation. That is, various control amounts are corrected according to the difference in the residual fuel amount that changes according to the difference in the valve closing pressure. Then, the pump control means M9 controls the driving of the fuel injection pump M3 based on the corrected various control amounts, and adjusts the fuel to be pumped to the fuel injection nozzle M2 through the fuel system M5.

Here, the residual fuel amount corresponds to the amount of fuel actually confined in the fuel system M5 when the fuel injection nozzle M2 is closed. It is known that the residual fuel amount has a stronger correlation with the valve closing pressure than the valve opening pressure of the fuel injection nozzle M2, and changes directly due to the difference in the valve closing pressure. It is also known that the residual fuel amount deviation, that is, the difference in the residual fuel amount affects the difference in the amount of fuel injected from the fuel injection nozzle M2 and the injection timing.

Therefore, a more appropriate residual fuel amount can be obtained from the valve closing pressure, and a more appropriate residual fuel amount deviation can be obtained. In addition, in each fuel injection, the influence of the residual fuel amount is more appropriately eliminated from the various control amounts for the fuel injection, and the fuel injection control is performed without being affected by the aging of the fuel injection nozzle M2. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which a fuel injection control device for a high-pressure injection internal combustion engine according to the present invention is embodied in an electronically controlled diesel engine of an automobile will be described in detail with reference to FIGS.

FIG. 2 shows a schematic configuration of a diesel engine system with a supercharger in this embodiment, and FIG. 3 shows the distribution type fuel injection pump 1 in an enlarged manner. The fuel injection pump 1 has a drive pulley 2, and the drive pulley 2 is a diesel engine 3 as a high-pressure injection internal combustion engine.
To the crankshaft 40 via a belt or the like. When the drive pulley 2 is rotated by the crankshaft 40 and the fuel injection pump 1 is driven, a fuel pipe is provided to the fuel injection nozzle 4 provided for each cylinder (four cylinders in this embodiment) of the diesel engine 3. Fuel is pumped through the passage 4a.

In this embodiment, the fuel injection nozzle 4 is an automatic valve including a needle valve and a spring for adjusting the valve opening pressure of the needle valve. The valve is opened. Therefore, the fuel injected from the fuel injection pump 1 applies a fuel pressure P equal to or higher than a predetermined level to the fuel injection nozzle 4, whereby fuel is injected from the nozzle 4 to the diesel engine 3.

The fuel injection pump 1 has a drive shaft 5
The drive pulley 2 is attached to the tip of the drive shaft 5. In the middle of the drive shaft 5 is provided a fuel feed pump 6 (developed by 90 degrees in this figure) composed of a vane type pump. A disk-shaped pulsar 7 is attached to the base end side of the drive shaft 5. On the outer peripheral surface of the pulsar 7, missing teeth of the same number as the number of cylinders of the diesel engine 3, that is, four (in total, “eight”) missing teeth are formed at equal angular intervals in this embodiment. Also, between each missing tooth,
Fourteen projections (a total of "56") are formed at equal angular intervals. 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. A plurality of cam rollers 10 facing the cam face 8a of the cam plate 8 are mounted in the circumferential direction of the roller ring 9. The cam faces 8 a are provided in the same number as the number of cylinders of the diesel engine 3. The cam plate 8 is a spring 1
1 is urged to engage with the cam roller 10.

A base end of a plunger 12 for fuel pressurization is attached to the cam plate 8 so as to be integrally rotatable. Then, the cam plate 8 and the plunger 12 are integrally driven to rotate as the drive shaft 5 rotates.
That is, the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via the coupling, so that the cam plate 8 rotates while engaging with the cam roller 10. As a result, the cam plate 8 is reciprocated in the horizontal direction in the figure by the same number as the number of cylinders while being rotated, and the plunger 12 is reciprocated in the same direction while being rotated. That is, the cam face 8a is the cam roller 1 of the roller ring 9.
Plunger 12 moves forward (lift) in the process of climbing to zero
Is done. On the contrary, the cam face 8a is
Plunger 12 moves back in the process of getting over 0 (down)
Is done.

A cylinder 14 is formed in the pump housing 13, and the plunger 12 is fitted into the cylinder 14. A high-pressure chamber 15 is provided between the tip surface of the plunger 12 and the bottom surface of the cylinder 14. In addition, suction grooves 16 and distribution ports 17 are formed on the outer periphery of the distal end side of the plunger 12 by the same number as the number of cylinders. Further, corresponding to the suction groove 16 and the distribution port 17,
A distribution passage 18 and a suction port 19 are formed in the pump housing 13.

In the pump housing 13 of this embodiment, a delivery valve 3 composed of a constant pressure valve (CPV) is provided at the outlet side of each distribution passage 18.
6 are provided. The delivery valve 36 is for preventing a backflow of the fuel pressure-fed from the distribution passage 18 to the fuel pipe 4a, and is opened when a fuel pressure P of a certain level or more is obtained.

When the drive shaft 5 is rotated and the fuel feed pump 6 is driven, fuel is introduced from a fuel tank (not shown) into the fuel chamber 21 through the fuel supply port 20. In 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, in 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 through the fuel pipe 4a and injected.

In the pump housing 13, the high pressure chamber 1
A spill passage 22 for causing fuel to overflow (spill) is formed between the fuel chamber 5 and the fuel chamber 21. An electromagnetic spill valve 23 is provided in the middle of the spill passage 22. Then, the electromagnetic spill valve 23 is opened and closed to adjust the spill of the fuel from the high-pressure chamber 15. The electromagnetic spill valve 23 is a normally open type valve. When the coil 24 is not energized (off), the spill passage 22 is opened by the valve body 25, that is, the valve is opened, and the fuel in the high-pressure chamber 15 is released from the fuel chamber 21. Spilled into On the other hand, when the coil 24 is energized (turned on), the spill passage 22 is closed by the valve body 25, that is, the valve is closed, and the spill of fuel from the high-pressure chamber 15 to the fuel chamber 21 is shut off.

Therefore, the electromagnetic spill valve 23 is controlled to be turned on and off by energization, whereby the valve 23 is controlled to close and open, and the spill of fuel from the high-pressure chamber 15 to the fuel chamber 21 is adjusted. When the electromagnetic spill valve 23 is opened during the compression stroke of the plunger 12, the high-pressure chamber 1 is opened.
The fuel in the fuel injection nozzle 4 is depressurized and the fuel injection from the fuel injection nozzle 4 is stopped. That is, even when the plunger 12 moves forward, while the electromagnetic spill valve 23 is opened,
The fuel pressure in the high-pressure chamber 15 does not increase and the fuel injection nozzle 4
Is not injected. Also, during the forward movement of the plunger 12, by controlling the valve opening timing of the electromagnetic spill valve 23, the end timing of the fuel injection from the fuel injection nozzle 4 is adjusted, and the fuel injection amount to the cylinder is controlled. .

Below the pump housing 13, there is provided a timer device (expanded by "90 degrees" in this figure) 26 for controlling the fuel injection timing to the advance side or the retard side. . This timer device 26 changes the rotation position of the roller ring 9 with respect to the rotation direction of the drive shaft 5 to change the timing at which the cam face 8a engages with the cam roller 10, that is, the timing at which the plunger 12 reciprocates. belongs to.

The timer device 26 is driven by control hydraulic pressure, and includes a timer housing 27 and a timer piston 28 fitted in the housing 27. Further, both sides of the timer piston 28 in the timer housing 27 are a low-pressure chamber 29 and a pressurizing chamber 30, respectively. The low-pressure chamber 29 has a timer piston 28
A timer spring 31 is provided to urge the pressure chamber 30 into the pressure chamber 30. Further, the timer piston 28 is connected to the roller ring 9 via a slide pin 32.

The fuel pressurized by the fuel feed pump 6 is introduced into the pressurizing chamber 30. The position of the timer piston 28 is determined by the balance between the fuel pressure and the urging force of the timer spring 31. Further, by determining the position of the timer piston 28, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 via the cam plate 8 is determined.

As the control oil pressure of the timer device 26, the fuel pressure inside the fuel injection pump 1 is used. To adjust the fuel pressure, the timer device 26 is provided with a timer control valve (TCV) 33. That is, a communication path 34 is provided between the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27, and the communication path 34
The TCV 33 is provided in the middle of. The TCV 33 is an electromagnetic valve whose opening is controlled by a duty-controlled energization signal. The opening of the TCV 33 is controlled, so that the fuel pressure in the pressurizing chamber 30 is adjusted. Then, by adjusting the fuel pressure, the reciprocating timing of the plunger 12 is controlled.
Is controlled to be advanced or retarded.

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 the pulsar when it is crossed by a projection or the like of the pulsar 7 and outputs the signal as a pulse signal. That is, the rotation speed sensor 35 outputs an engine rotation pulse signal for each constant crank angle. At the same time, the rotation speed sensor 35 outputs an engine rotation pulse signal corresponding to a fixed crank angle due to a missing tooth of the pulser 7 as a reference position signal. The rotation speed sensor 35 outputs a series of engine rotation pulse signals as signals for obtaining the engine rotation speed NE.
Since the rotation speed sensor 35 is integrated with the roller ring 9, it can output a reference engine rotation pulse signal at a fixed timing with respect to the reciprocation of the plunger 12 regardless of the control operation of the timer device 26. .

In addition, the pump housing 13 is provided with a fuel temperature sensor 37 for detecting the temperature of the fuel housed in the fuel chamber 21, that is, the fuel temperature THF.

Next, the diesel engine 3 will be described. 2, in the diesel engine 3, a main combustion chamber 44 corresponding to each cylinder is formed by a cylinder bore 41, a piston 42, and a cylinder head 43. In the cylinder head 43, sub combustion chambers 45 communicating with the main combustion chambers 44 are formed. Then, fuel is injected into each sub-combustion chamber 45 from each fuel injection nozzle 4. Each sub-combustion chamber 45 is provided with a well-known glow plug 46 as a start-up assist device.

As shown in FIGS. 2 and 4, each fuel injection nozzle 4 of this embodiment is provided with a pressure sensor 47 as fuel pressure detecting means. The pressure sensor 47 detects the pressure of the fuel pressure-fed from the fuel injection pump 1 to each of the fuel injection nozzles 4, that is, the fuel pressure P.
Is detected as the valve closing pressure when the valve is closed, and a signal corresponding to the magnitude of the detected value is output.

On the other hand, the diesel engine 3 is provided with an intake passage 49 and an exhaust passage 50 communicating with each cylinder. Further, a compressor 52 of a turbocharger 51 constituting a supercharger is provided in the intake passage 49,
A turbine 53 of a turbocharger 51 is provided in the exhaust passage 50.
Is provided. Further, a waste gate valve 54 is provided in the exhaust passage 50. As is well known, the turbocharger 51 uses the energy of the exhaust gas to rotate the turbine 53, and rotates the compressor 52 coaxially therewith to increase the pressure of the intake air. Then, by increasing the pressure of the intake air, high-density air is sent into the main combustion chamber 44 and a large amount of fuel injected through the sub-combustion chamber 45 is burned, so that the output of the diesel engine 3 is increased. The opening and closing of the waste gate valve 54 causes the turbocharger 5 to open and close.
The boost pressure level of the intake air by 1 is adjusted.

Between the intake passage 49 and the exhaust passage 50,
Exhaust gas recirculation valve passage (EG
An R path 56 is provided. Then, a part of the exhaust gas in the exhaust passage 50 is recirculated by the EGR passage 56 near the intake port 55 in the intake passage 49.
An EGR valve 57 is provided in the middle of the EGR passage 56, and the EGR valve 57 controls the exhaust gas recirculation amount (E
GR amount) is adjusted. Further, in order to open and close the EGR valve 57, an electric vacuum regulating valve (EVRV) 58 whose opening is adjusted is controlled.
Is provided. Then, EGRV58 is used for EGR
When the valve 57 is driven to open and close, the EGR passage 5
E guided from the exhaust passage 50 to the intake passage 49 through
The GR amount is adjusted.

A throttle valve 59 is provided in the middle of the intake passage 49. The throttle valve 59 is opened and closed in conjunction with the depression of an accelerator pedal 60. In the intake passage 49,
A bypass passage 61 is provided alongside the throttle valve 55, and a bypass throttle valve 62 is provided in the passage 61. In order to open and close the bypass throttle valve 62, a two-stage diaphragm chamber type actuator 63 is provided. Also, two vacuum switching valves (VS) for driving the actuator 63 are provided.
V) 64, 65 are provided. And each VSV6
The bypass throttle valve 62 is controlled to open and close by driving the actuator 63 with the on / off control of the valves 4 and 65. For example, the bypass throttle valve 62 is controlled to be in a half-open state in order to reduce noise and vibration during idling operation, is controlled to be in a fully open state in normal operation, and is controlled to be in a fully closed state in order to smoothly stop the operation. Is done.

The above-described electromagnetic spill valve 23, TCV3
3, glow plug 46, EVRV58 and each VSV6
4 and 65 are electronic control units (hereinafter simply referred to as “ECU”).
71 are electrically connected to each other. The drive timing of each of the members 23, 33, 46, 58, 64, 65 is controlled by the ECU 71.

As sensors for detecting the operating state of the diesel engine 3, the following various sensors are provided in addition to the rotation speed sensor 35 described above. That is, near the air cleaner 66 provided at the inlet of the intake passage 49, the temperature of the air taken into the intake passage 49, that is, the intake air temperature THA is detected, and a signal corresponding to the detected value is output. An intake air temperature sensor 72 is provided. In the vicinity of the throttle valve 59, there is provided an accelerator sensor 73 which detects an accelerator opening ACCP corresponding to the engine load from the open / close position of the valve 59 and outputs a signal corresponding to the magnitude of the detected value. I have. In the vicinity of the intake port 55, an intake pressure sensor 74 that detects the pressure of the intake air after being supercharged by the turbocharger 51, that is, the supercharging pressure PiM, and outputs a signal corresponding to the magnitude of the detected value. Is provided. Further, the diesel engine 3 is provided with a water temperature sensor 75 which detects the temperature of the cooling water, that is, the cooling water temperature THW, and outputs a signal corresponding to the magnitude of the detected value. Further, the diesel engine 3 is provided with a crank angle sensor 76 that detects 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, and outputs a signal corresponding to the rotation position. Have been. Further, a transmission (not shown) is provided with a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SPD. This vehicle speed sensor 7
Reference numeral 7 includes a magnet 77a rotated by an output shaft of the transmission, and a reed switch 77b is periodically turned on by the magnet 77a to output a pulse signal corresponding to the vehicle speed SPD.

In this embodiment, the ECU 71 constitutes a residual fuel amount calculating means, a residual fuel amount deviation calculating means, a control amount correcting means, and a pump control means. The above-described sensors 72 to 77, the rotation speed sensor 35, the fuel temperature sensor 37, and the pressure sensor 47 are connected to the ECU 71, respectively. Also, the ECU 71 controls each sensor 3
5, 37, 47, 72 to 77, the electromagnetic spill valve 23, the TCV 33, the glow plug 4
6. The EVRV 58 and the VSVs 64 and 65 are suitably controlled.

Next, the configuration of the ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 includes a central processing unit (CPU) 81, a read-only memory (ROM) 82 in which a predetermined control program, a map, and the like are stored in advance,
A random access memory (RAM) 83 for temporarily storing the calculation results of the PU 81, a backup RAM 84 for storing the stored data, and the like are provided. And ECU
Reference numeral 71 denotes a logical operation circuit in which these units 81 to 84 are connected to an input port 85, an output port 86, and the like via a bus 87.

The input port 85 is provided with the above-mentioned intake air temperature sensor 72, accelerator sensor 73, intake air pressure sensor 74, water temperature sensor 75, pressure sensor 47 and fuel temperature sensor 37 in the buffers 88, 89, 90, 91, 92. , 93, a multiplexer 94 and an A / D converter 95. Similarly, the input port 85 includes the above-described rotation speed sensor 35, crank angle sensor 76, and vehicle speed sensor 77.
Are connected via a waveform shaping circuit 96. Then, the CPU 81 reads, as input values, signals from the sensors 35, 37, 47, 72 to 77, etc., which are input via the input port 85. The output ports 86 are connected to the respective driving circuits 97, 98, 99, 100, 101, 102.
The electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EVRV 58, and the VSVs 64, 65, etc., are connected to each other via the. Then, the CPU 81 controls each sensor 3
The electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EVRV 58, and the VSVs 64 and 65 are suitably controlled based on the input values read from 5, 37, 47, 72 to 77.

In this embodiment, the CPU 81 has a timer function. Also, in this embodiment,
The glow plug 46 and the pressure sensor 47 are provided for each cylinder of the diesel engine 3.
Only one of them is shown in the block diagram of FIG.

Next, processing operations for fuel injection control executed by the above-described ECU 71 will be described with reference to FIGS.
It will be described according to. FIG. 6 is a flowchart showing a “subroutine” process executed at each time ti measured by the timer function of the CPU 81 among the processes executed by the ECU 71.

When the process proceeds to this routine, first, at step 110, the fuel pressure P is sampled based on the signal from the pressure sensor 47. Subsequently, in step 120, the fuel pressure Pi at the time ti at that time is calculated.

Next, at step 130, a one-time differential value (dPi / dti) is calculated as a change rate of the fuel pressure Pi at the time ti at that time. Further, in step 140, the fuel pressure P at the current time ti
The second derivative (d ² Pi / d) corresponding to the change in the rate of change of i
ti ² ) is calculated.

In step 150, the fuel pressure Pi determined this time and the one-time differential value (dPi / dt)
i) and the second derivative (d ² Pi / dti ² ) at time ti
Are respectively stored in the RAM 83 as calculation data corresponding to the above, and the subsequent processing is temporarily terminated.

Therefore, according to the above-described "subroutine" processing, each time one fuel injection is executed, the fuel pressure Pi corresponding to each time ti and the one-time differential value (dPi / dti) are obtained.
And the second derivative (d ² Pi / dti ² ) are sequentially stored in the RAM 83 as calculation data.

FIGS. 7 and 8 show a "Pe calculation routine" for calculating the injection end pressure Pe used for fuel injection control, among the processes executed by the ECU 71.
5 is a flowchart showing the processing contents of FIG. The processing of this routine is executed every time one fuel injection is performed.

When the process proceeds to this routine, first, at step 210, the fuel pressure Pi corresponding to the time ti stored in the RAM 83 and its one-time differential value (d
Pi / dti) and time t (i−
The fuel pressure P (i-1) corresponding to 1) is read.

Subsequently, at step 220, the time t
The fuel pressure Pi corresponding to i is the time t (i−
It is determined whether the fuel pressure is higher than the fuel pressure P (i-1) corresponding to 1). If the fuel pressure Pi is not higher than the previous fuel pressure P (i-1), the fuel pressure P
It is determined that the process is not an increase process, and the process jumps to step 210 and repeats the processes of steps 210 and 220.
If the fuel pressure Pi is higher than the previous fuel pressure P (i-1) in step 220, it is determined that the fuel pressure P is in the process of increasing and the process proceeds to step 230.

In step 230, it is determined whether or not the once-differentiated value (dPi / dti) read this time exceeds a predetermined threshold value d1 on the plus side for a predetermined reference time T1. Here, the first derivative (dPi / dt)
If i) exceeds the threshold value d1 and the reference time T1 has not elapsed, the process jumps to step 210 and repeats the processing of steps 210 to 230. Step 23
At 0, if the one-time differential value (dPi / dti) exceeds the threshold value d1 and the reference time T1 has elapsed, it is determined that the fuel pressure P is in the process of increasing the fuel pressure P to start fuel injection, and step 240 is performed. Move to.

Then, in step 240, RA
The fuel pressure P corresponding to the time ti stored in M83
i (dPi / dti) and the second derivative (d
² Pi / dti ² ).

Next, in step 250, it is determined whether or not the second differential value (d ² Pi / dti ² ) read this time is smaller than a reference value α. Here, if the second derivative (d ² Pi / dti ² ) is not smaller than the reference value α, it is determined that the rate of change of the fuel pressure Pi has not dropped significantly, and the routine jumps to step 240, where it jumps to step 240. Step 250 is repeated. On the other hand, in step 250, the second derivative (d ² Pi / dt)
If i ² ) is smaller than the reference value α, it is determined that the rate of change of the fuel pressure P has greatly decreased during the process of increasing the fuel pressure P, and the routine proceeds to step 260.

Then, in step 260, the once-differentiated value (dPi / dti) read this time falls below a predetermined threshold value d2 on the negative side and a predetermined reference time T2
Is determined. Here, when the one-time differential value (dPi / dti) is less than the threshold value d2 and the reference time T2 has not elapsed, the one-time differential value (dPi / dti) is reduced due to the start of fuel injection. Assuming that no change has occurred, the process jumps to step 240 and repeats the processing of steps 240 to 260. Step 26
At 0, when the one-time differential value (dPi / dti) falls below the threshold value d2 and the reference time T2 has elapsed, the one-time differential value (dPi / dti) due to the start of fuel injection.
Then, the process proceeds to step 270 assuming that the change in the fuel pressure P has definitely decreased.

In step 270, the RAM 83 is traced back to the time ti when the one-time differential value (dPi / dti) becomes "0" from the time when it is determined that the rate of change of the fuel pressure P has definitely decreased. Search the stored operation data. Here, the time ti when the one-time differential value (dPi / dti) becomes “0” is the time when the rate of increase of the fuel pressure P first changes from positive to negative during the process of increasing the fuel pressure P. Yes, it is.

In step 280, at the time ti when the one-time differential value (dPi / dti) becomes “0” in the retrieved calculation data, the time ti is determined by the fuel injection from the fuel injection nozzle 4. The start time is determined, and the time ti is set as the injection start time ts. Further, the fuel pressure Pi at the time ts is set as the injection start pressure Ps corresponding to the valve opening pressure when the fuel injection nozzle 4 is opened.

Subsequently, at step 290, the RAM
83, the fuel pressure Pi corresponding to the time ti
And the fuel pressure P (i-1) corresponding to the time t (i-1) immediately before the time ti.

Subsequently, in step 300, it is determined whether or not the fuel pressure Pi read this time is smaller than the injection start pressure Ps obtained in step 280. If the fuel pressure Pi is not smaller than the injection start pressure Ps, the routine jumps to step 290, where step 29 is executed.
Each process of 0 and 300 is repeated. If the fuel pressure Pi is smaller than the injection start pressure Ps in step 300, the process proceeds to step 310.

In step 310, it is determined whether the fuel pressure Pi corresponding to time ti is lower than the fuel pressure P (i-1) corresponding to the immediately preceding time t (i-1). Then, the fuel pressure Pi becomes the previous fuel pressure P
If it is not smaller than (i-1), it is determined that the process is not the process of decreasing the fuel pressure P, and the process jumps to step 290 and repeats the processes of steps 290 to 310. or,
When the fuel pressure Pi is smaller than the previous fuel pressure P (i-1) in step 310, the fuel pressure P is reduced in a range lower than the injection start pressure Ps, and the fuel injection ends. As the range that should lead to
Move to step 320.

At step 320, prior to the current fuel injection stroke, the elapsed time Toff from when the electromagnetic spill valve 23 was turned off, that is, when it was closed, is read. The elapsed time Toff is counted up by a separate processing routine. And step 33
0, the elapsed time Toff read this time is smaller than a predetermined reference time T3, that is, the elapsed time Toff
It is determined whether or not off has not reached the reference time T3. Here, when the elapsed time Toff has reached the reference time T3, the subsequent processing is once ended as it is.
On the other hand, when the elapsed time Toff has not reached the reference time T3, it is determined that the fuel injection end timing is to be determined.
Move to step 340.

In step 340, the one-time differential value (dPi / dti) of the fuel pressure Pi corresponding to the time ti stored in the RAM 83 is read. Then, in step 350, the once-differentiated value (dP
It is determined whether or not (i / dti) is smaller than a certain threshold d3 on the minus side. Here, the first derivative (dPi /
If dti) is not smaller than the threshold value d3, it is determined that the rate of change of the fuel pressure P is not sufficiently small, that is, the rate of decrease of the fuel pressure P is not in the increasing process, and the process jumps to step 340. Steps 340 and 350 are repeated. In contrast, in step 350,
If the first derivative (dPi / dti) is smaller than the threshold value d3, it is determined that the decreasing rate of the fuel pressure P is in the process of increasing, and the process proceeds to step 360.

In step 360, the one-time differential value (dPi / dti) of the fuel pressure Pi corresponding to the time ti stored in the RAM 83 is read. Then, in step 370, the one-time differential value (dP
i / dti) is a threshold d4 (d3 <
It is determined whether it is larger than d4). Here, if the one-time differential value (dPi / dti) is not larger than the threshold value d4, it is assumed that the rate of change of the fuel pressure P has not once increased from a small state, that is, the rate of decrease of the fuel pressure P Is not changed from the increasing process to the decreasing process, the process jumps to step 360, and step 36 is executed.
The process of 0,370 is repeated. Step 3
In 70, if the one-time differential value (dPi / dti) is larger than the threshold value d4, it is determined that the decreasing rate of the fuel pressure P has changed from the increasing process to the decreasing process, and the process proceeds to step 380.

In step 380, the time ti at the time when the one-time differential value (dPi / dti) becomes larger than the threshold value d4 in the immediately preceding step 370 is defined as the fuel injection end timing at the fuel injection nozzle 4. Judgment is made and the time ti is set as the injection end time te. Further, “te−T” which is earlier than the injection end time te by the correction time TP.
P ”, the fuel pressure Pi at the time of
End pressure Pe corresponding to the valve closing pressure when the valve is closed
Set as Here, it is known that the fuel pressure P at the actual injection end time te appears slightly behind on the waveform detected by the pressure sensor 47 due to the fuel property of the fuel system, the path length, and the like. The above-mentioned correction time TP is for compensating for the delay, and is an extremely short time set according to the difference in fuel system conditions. Here, the correction time TP can be set to “20 to 100 μs”.

When the processing of step 380 is completed, the subsequent processing is temporarily terminated, and the processing from step 210 is started again after waiting for the next fuel injection. Therefore, according to the processing of the "Pe calculation routine", each time one fuel injection is executed, the injection start time ts and the injection start pressure Ps at that time, and the injection end time te and the injection end The pressure Pe is determined respectively. Then, those values are respectively stored in the RAM 83.

Here, the injection start time ts, the injection start pressure Ps, the injection end time te, the injection end pressure Pe, the fuel pressure P and the one-time differential value (dPi) obtained as described above are obtained.
An example of the behavior of / dti) will be described with reference to the time chart of FIG.

When the plunger 12 of the fuel injection pump 1 starts to move forward when the fuel is injected from the fuel injection nozzle 4, the fuel pressure P increases at time t1, as shown in FIG. Begin to. And the fuel pressure P
Gradually increases with the forward movement of the plunger 12. At this time, the one time differential value (dP / dt) of the fuel pressure P changes as shown in FIG. Here, immediately after the time t1, when the one-time derivative value (dP / dt) exceeds the plus threshold value d1 for the reference time T1, the ECU 71 sets
It is determined that this is a process of increasing the fuel pressure P to start the fuel injection. Thereafter, at time t2, when the increasing fuel pressure P undergoes a large inflection, its one-time differential value (dP /
dt) drops significantly. And immediately after time t2,
The one-time differential value (dP / dt) is a negative threshold d2
Is less than the reference time T2, the ECU 71 determines that the rate of change of the fuel pressure P has definitely decreased due to the start of fuel injection. In the ECU 71,
One-time differential value (dPi / dti) retroactively from the judgment time
Is obtained at time t2 at which becomes “0”, and the time t2 is obtained as the injection start time ts. Further, at time t2
Is obtained as the injection start pressure Ps corresponding to the valve opening pressure. That is, as shown in FIG. 7A, the injection start time ts corresponding to the inflection point A where the rate of increase of the fuel pressure P first changes from positive to negative, and the injection start pressure Ps at that time are obtained. .

Thereafter, when fuel injection continues from time t2,
Accordingly, the fuel pressure P and the first derivative (dPi / dt)
i) shows a change as shown in FIGS. Then, in the process where the fuel pressure P decreases in a range lower than the injection start pressure Ps, if the one time differential value (dPi / dti) of the fuel pressure P falls below the negative threshold value d3 at time t3, and drops significantly. In the ECU 71, the fuel pressure P
It is determined that this is the process of increasing the rate of decrease. The following time t4
, The first derivative of the fuel pressure P (dPi / dti)
Once rises above the negative threshold d4, the ECU 71 determines that the rate of decrease in the fuel pressure P changes from an increasing process to a once decreasing process. Then, the time t4 is obtained as the injection end time te in the fuel injection nozzle 4. At that time t
4 before the correction time TP (in this case, the time t
The fuel pressure P in 3) is obtained as the injection end pressure Pe corresponding to the valve closing pressure. That is, as shown in FIG. 7A, the injection end time te corresponding to the inflection point B and the injection end pressure Pe corresponding to the inflection point B at which the decrease stops once during the process of decreasing the fuel pressure P are obtained. It is done. Then, the injection start time ts to the injection end time te
Is the injection period during which the fuel injection was actually performed.

In this embodiment, the following fuel injection amount control is executed using the injection end pressure Pe obtained as described above. That is, FIG.
Is a flowchart showing the processing content of a "fuel injection amount control routine" executed by the control unit, and is periodically executed at predetermined intervals.

When the process proceeds to this routine, first, at step 410, the engine speed NE is determined based on various signals from the rotation speed sensor 35, the fuel temperature sensor 37, the accelerator sensor 73, the intake pressure sensor 74, the water temperature sensor 75, and the like. , The fuel temperature THF, the accelerator opening ACCP, the supercharging pressure PiM, the cooling water temperature THW, and the like.

Subsequently, in step 420, a basic injection amount Qb corresponding to the current operating state is calculated based on the engine speed NE and the accelerator opening ACCP. or,
In step 430, the basic injection amount Qb obtained this time based on the current cooling water temperature THW, the supercharging pressure PiM, etc.
To calculate the corrected injection amount Q1. That is, the corrected injection amount Q1 is obtained in a cold state or in accordance with the operation state of the turbocharger 51.

In step 440, the fuel temperature THF read this time and the corrected injection amount Q obtained this time
1, the reference residual fuel amount Qr that will remain in the fuel system from the fuel injection pump 1 to the fuel injection nozzle 4 when the fuel injection nozzle 4 is closed, that is, the reference residual fuel amount Qr
Calculate es. This calculation is performed with reference to a predetermined map for the relationship between the reference residual fuel amount Qres with respect to the fuel temperature THF and the corrected injection amount Q1.

Thereafter, in step 450, the RAM
The latest injection end pressure Pe stored in 83 is read. Then, in step 460, the actual remaining fuel amount Qre remaining in the fuel system from the fuel injection pump 1 to the fuel injection nozzle 4 is calculated based on the latest injection end pressure Pe and the like read this time. This residual fuel amount Qre
Is performed according to the following formula.

Qre = Vi * ε * Pe Here, “Vi” means a volume volume in the fuel system from the fuel injection pump 1 to the fuel injection nozzle 4 and “ε”.
Means the bulk modulus of the fuel. Therefore, in the above formula, the actual residual fuel amount Qre is calculated based on the actual injection end pressure Pe.

In step 470, the difference between the reference residual fuel amount Qres obtained this time and the actual residual fuel amount Qre is calculated, and the calculation result is set as the residual fuel amount deviation ΔQre.

Subsequently, at step 480, the corrected injection amount Q1 and the residual fuel amount deviation ΔQre obtained this time are obtained.
, The final target injection amount Q is calculated. That is, the target injection amount Q is obtained by further correcting the corrected injection amount Q1 by the residual fuel amount deviation ΔQre.

Then, in step 490, fuel injection is executed based on the target injection amount Q obtained this time, and the subsequent processing is temporarily terminated. That is, by controlling the electromagnetic spill valve 23 based on the target injection amount Q, the pressure of the fuel injected from the fuel injection pump 1 to the fuel injection nozzle 4 is controlled, thereby controlling the fuel injection amount injected from the fuel injection nozzle 4. I do.

As described above, according to the fuel injection control device of this embodiment, the deviation of the residual fuel amount Qre in the fuel system from the fuel injection pump 1 to the fuel injection nozzle 4 is determined by the target injection amount. Q is fed back to execute the fuel injection amount control.

That is, when one fuel injection is performed, the injection end pressure Pe corresponding to the valve closing pressure when the fuel injection nozzle 4 is closed is detected. Further, based on the detected injection end pressure Pe, the actual residual fuel amount Qr in the fuel system from the fuel injection pump 1 to the fuel injection nozzle 4 is determined.
e is calculated. Further, a difference between the reference residual fuel amount Qres when the fuel injection nozzle 4 is closed and the actual residual fuel amount Qre is calculated as a residual fuel amount deviation ΔQre. Then, the corrected target injection amount Q1 is determined by correcting the corrected injection amount Q1 determined according to the operating state based on the residual fuel amount deviation ΔQre. That is,
Injection end pressure P corresponding to valve closing pressure of fuel injection nozzle 4
By correcting the corrected injection amount Q1 with the residual fuel amount deviation ΔQre corresponding to the difference e, the target injection amount Q is obtained. The drive of the fuel injection pump 1 is controlled based on the target injection amount Q, whereby the amount of fuel pumped to the fuel injection nozzle 4 through the fuel system is controlled.

Here, the residual fuel amount Qre corresponds to the amount of fuel actually trapped in the fuel system when the fuel injection nozzle 4 is closed. Then, the residual fuel amount Qre
Has a stronger correlation with the valve closing pressure than the valve opening pressure of the fuel injection nozzle 4, and the injection end pressure Pe corresponding to the valve closing pressure.
It has been confirmed that it changes directly due to the difference.
The residual fuel amount deviation ΔQre, that is, the residual fuel amount Qr
It has been confirmed that the difference in e affects the difference in the amount of fuel injected from the fuel injection nozzle 4.

Accordingly, a more appropriate residual fuel amount Qre can be obtained from the injection end pressure Pe, and a more appropriate residual fuel amount deviation ΔQre can be obtained. Also, in each fuel injection, the residual fuel amount Qre
Is more appropriately eliminated, and the fuel injection amount control is executed without being affected by the aging of the fuel injection nozzle 4 or the like.

As a result, in the fuel injection amount control, the residual fuel amount deviation Δ
The fuel injection amount can be accurately corrected based on Qre. Further, even in a direct injection type diesel engine in which the injection rate of the fuel injection nozzle is increased, a more appropriate residual fuel amount deviation ΔQre can be obtained from the injection end pressure Pe, and more accurate fuel injection amount control can be performed. Can be performed. That is, irrespective of the rotation range of the diesel engine 3 or of the direct injection type, the difference in the residual fuel amount Qre in the fuel system can be determined with high accuracy. The fuel injection amount control can be performed with higher accuracy than in the above. As a result, the emission of smoke and nitrogen oxides (NOx) from the diesel engine 3 can be more appropriately suppressed.

Further, in this embodiment, a more specific study is made in obtaining the injection end pressure Pe at the fuel injection nozzle 4. That is, the waveform of the fuel pressure P is monitored by the pressure sensor 47 provided in the fuel injection nozzle 4. Then, when the fuel pressure P is in a decreasing process in a range lower than the injection start pressure Ps, the rate of decrease of the fuel pressure P changes from an increasing process to a once decreasing process from the first differential value (dPi / dti). A point in time is required.
Here, the point where the decreasing rate of the fuel pressure P changes from the increasing process to the decreasing process corresponds to a portion where the decrease in the fuel pressure P temporarily stops decreasing when the fuel injection nozzle 4 is closed. In other words, in the waveform patterns shown in FIGS. 9A and 9B, in the process of decreasing the fuel pressure P, the time when the decreasing rate changes from the increasing process to the decreasing process is defined as the fuel pressure P
Means the inflection point B when the descent stops for a moment.

Accordingly, the actual injection end time te is specified from the inflection point B of the fuel pressure P, and the injection end pressure Pe corresponding to the valve closing pressure is specified from the injection end time te. You. Therefore, a more appropriate injection end pressure Pe can be obtained by eliminating the influence of the fuel injection nozzle 4 over time, individual differences, noise, and the like. As a result, the injection end pressure Pe can be determined more accurately, and the residual fuel amount Qre and the residual fuel amount deviation ΔQre, and thus the target injection amount Q, can be determined more accurately. In this sense, the fuel injection amount control can be performed with higher accuracy.

Further, in this embodiment, in order to control the fuel injection amount from the fuel injection nozzle 4 to the target injection amount Q, the fuel amount pumped from the fuel injection pump 1 itself is adjusted. . Therefore, unlike a configuration in which a special pressure adjusting means is provided to adjust the valve opening pressure or the valve closing pressure of the fuel injection nozzle, in this embodiment, the mechanism for fuel injection is not complicated. The fuel injection nozzle 4 as described above may be used.

It should be noted that the present invention is not limited to the above-described embodiment, and may be implemented as follows, with a part of the configuration being appropriately changed without departing from the spirit of the invention. (1) In the embodiment, the target injection amount Q is obtained by correcting the corrected injection amount Q1 based on the residual fuel amount deviation ΔQre, and the fuel injection amount control is executed based on the target injection amount Q. did. On the other hand, the residual fuel amount deviation Δ
The target injection start timing may be determined by correcting the injection start timing based on Qre, and the fuel injection timing control may be executed based on the target injection start timing.
That is, the various control amounts for the fuel injection to be corrected include the fuel injection amount and the fuel injection timing.

(2) In the above embodiment, the injection end time te
Pressure Pi at a point in time that is earlier than correction time TP
Was set as the injection end pressure Pe corresponding to the valve closing pressure. On the other hand, for example, the average value of the fuel pressures Pi obtained in the range of “20 to 100 μs” that is traced back from the injection end time te is set as the injection end pressure Pe, or “20 to 100 μs” that is traced from the injection end time te May be set as the injection end pressure Pe at a specific point in time.

(3) In the above embodiment, the injection start time ts is determined in order to obtain the injection end pressure Pe corresponding to the valve closing pressure.
Although the injection start pressure Ps at that time was actually obtained and used, the injection end pressure may be obtained using a predetermined injection start time or injection start pressure.

(4) In the above embodiment, the pressure sensor 47 for detecting the fuel pressure P is connected to the fuel injection nozzle 4 of each cylinder.
However, the pressure sensor may be provided in the middle of the fuel pipe leading to each fuel injection nozzle, or may be provided corresponding to the high pressure chamber of the fuel injection pump.

(5) In the above embodiment, the diesel engine 3 is embodied as a high-pressure injection internal combustion engine. However, any high-pressure injection internal combustion engine having a fuel injection pump and a fuel injection nozzle is limited to the diesel engine. Instead, it can be embodied in a high-pressure gasoline injection engine or the like.

[0087]

As described above in detail, according to the present invention, the valve closing pressure is detected in consideration of the fact that the residual fuel amount has a stronger correlation with the valve closing pressure than the valve opening pressure of the fuel injection nozzle.
Since as to reflect the closing pressure for calculating a control amount for the fuel injection, the fuel injection, the braking effect of the residual fuel quantity from your amount for the fuel injection is more appropriately eliminated, The fuel injection control is performed without being affected by the aging of the fuel injection nozzle or the like. As a result, regardless of the rotation range of the internal combustion engine, whether or not the engine is of the direct injection type, etc., the difference in the amount of residual fuel in the fuel system can be accurately determined, and highly accurate fuel injection control is performed. It has an excellent effect of being able to do so.

[Brief description of the drawings]

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

FIG. 2 is a schematic diagram showing a supercharged diesel engine system according to an embodiment of the present invention.

FIG. 3 is a sectional view showing a distribution type fuel injection pump in one embodiment.

FIG. 4 is a diagram showing a pressure sensor provided in a fuel injection nozzle in one embodiment.

FIG. 5 is a block diagram showing a configuration of an ECU in one embodiment.

FIG. 6 is a flowchart showing a “subroutine” process executed by the ECU in one embodiment.

FIG. 7 is a flow chart illustrating the operation of “P” executed by the ECU in one embodiment;
It is a flow chart which shows the processing of "e operation routine."

FIG. 8 shows a Pe calculation routine in one embodiment.
6 is a flowchart showing the processing of FIG.

FIG. 9 is a time chart for explaining the behavior of the fuel pressure obtained during one fuel injection and its one-time differential value in one embodiment.

FIG. 10 is a flowchart illustrating processing of a “fuel injection amount control routine” executed by an ECU in one embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 3 ... Diesel engine as a high pressure injection internal combustion engine, 4 ... Fuel injection nozzle, 47 ... Pressure sensor as fuel pressure detecting means, 71 ... Residual fuel amount calculating means, residual fuel amount deviation calculating means, control ECU constituting the amount correction means and the pump control means.

Continuation of front page (56) References JP-A-4-203441 (JP, A) JP-A-4-203451 (JP, A) JP-A-4-203452 (JP, A) JP-A-62-32251 (JP) (A) JP-A-62-186034 (JP, A) JP-A-64-47944 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/04 F02D 45/00

Claims (2)

(57) [Claims] An internal combustion engine for pumping fuel from a fuel injection pump to a fuel injection nozzle, wherein the fuel pressure when the fuel injection nozzle is closed is detected as a valve closing pressure. Means and a fuel injection pump from the fuel injection pump based on the detection result of the detection means.
Calculates the control amount for the fuel injection reflecting the residual fuel quantity in the fuel system to the nozzle, the fuel injection of an internal combustion engine and a control means for driving and controlling the fuel injection pump based on the calculation result Quantity control device. 2. A valve is opened by obtaining a fuel pressure equal to or higher than a predetermined level.
Fuel injection for injecting fuel into a high pressure injection internal combustion engine
Nozzle and Drive control is performed to pump fuel to the fuel injection nozzle.
A fuel injection pump, The fuel pressure at the time of closing the fuel injection nozzle is a valve closing pressure.
Fuel pressure detecting means for detecting as a force, Based on the valve closing pressure detected by the fuel pressure detecting means,
Between the fuel injection pump and the fuel injection nozzle.
Residual fuel for calculating residual fuel amount in fuel system
Quantity calculation means, Residual fuel as a reference when the fuel injection nozzle is closed
Fuel amount and residual fuel calculated by the residual fuel amount calculating means
Residual to calculate the difference from the fuel amount as the residual fuel amount deviation
Fuel amount deviation calculating means, The fuel is calculated based on the calculation result of the residual fuel amount deviation calculating means.
Control amount correction method for correcting various control amounts for injection
Steps and The fuel injection is performed based on a correction result of the control amount correction unit.
Pump control means for driving and controlling the pump.
Fuel injection control device for high pressure injection internal combustion engine
Place.