JP2910483B2 - Abnormal diagnostic device for fuel injection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection device comprising a fuel injection pump and the like, and more particularly to a failure diagnosis device for fail-safe of the fuel injection device.

[0002]

2. Description of the Related Art Conventionally, a diesel engine, a high-pressure gasoline injection engine, and the like can be given as internal combustion engines equipped with the above-described fuel injection device. For example, in a fuel injection pump of an electronically controlled diesel engine, fuel in a high-pressure chamber is pressure-fed to a fuel injection nozzle by a lift of a plunger and injected into each cylinder of the diesel engine.
Then, the solenoid valve (electromagnetic spill valve) provided in the fuel injection pump is controlled to be opened so that the fuel injection amount at that time becomes the target injection amount determined according to the engine operating state. 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.

In this type of fuel injection pump,
It has been considered that there is a possibility that the electromagnetic spill valve will not open at the intended timing or will remain closed due to disconnection or short circuit of the electromagnetic spill valve, failure of the control circuit, or the like. In order to cope with this kind of abnormal situation, Japanese Patent Application Laid-Open No. 61-28735 discloses a technique for judging an abnormality in the system of the electromagnetic spill valve and performing fuel cut as one of fail-safes. I have.

That is, in this prior art, the fuel injection pump is provided with a fuel cut valve for shutting off the supply of fuel to the plunger high pressure chamber, in addition to the electromagnetic spill valve.
In the electronic control unit (ECU), the driving of the electromagnetic spill valve and the fuel cut valve is controlled, and a driving signal indicating whether the electromagnetic spill valve is operating is input. In addition, a rotation speed signal of the diesel engine is input to the ECU. Then, the ECU detects whether there is an abnormality in the system of the electromagnetic spill valve based on the drive signal and the rotation speed signal. Specifically, when the rotation speed signal is input and the drive signal is not an AC signal, an abnormality of the electromagnetic spill valve system is detected. Then, when the abnormality is detected, the fuel cut valve is driven to shut off the supply of fuel to the plunger high-pressure chamber. Usually, the electromagnetic spill valve is a normally-open type valve that is closed by energization (ON), so that fail-safe has already been achieved. Therefore, the reliability of the fail safe can be further improved by further adding the above fail safe.

[0005]

However, in the above prior art, the drive signal of the electromagnetic spill valve is monitored mainly on the premise of an electrical failure such as disconnection or short circuit of the electromagnetic spill valve or failure of the control circuit. I was just there. Therefore, when the electromagnetic spill valve itself mechanically fails, it cannot be detected as an abnormality. That is,
Even if the electric system of the electromagnetic spill valve is normal, it is rare that the electromagnetic spill valve becomes difficult to move or sticks in a closed state due to deterioration of fuel properties or biting of foreign matter. There is to be expected. Therefore, in the related art, fail-safe operation such as fuel cut cannot be achieved by coping with an abnormality caused by a mechanical failure of the electromagnetic spill valve.

Further, when determining an abnormality due to a mechanical failure of the electromagnetic spill valve, the degree of the mechanical failure does not always match the degree of the actual fuel injection failure. For this reason, simply monitoring the mechanical failure of the electromagnetic spill valve cannot directly evaluate the degree of abnormality on the actual fuel injection behavior. Therefore, an accurate fail-safe cannot be achieved in accordance with the degree of abnormality.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to deal with both abnormalities caused by an electrical failure of an electromagnetic spill valve and abnormalities caused by a mechanical failure. It is an object of the present invention to provide an abnormality diagnosis device for a fuel injection device that can diagnose the abnormality and accurately diagnose the abnormality according to the actual fuel injection behavior.

[0008]

In order to achieve the above object, according to the first aspect of the invention, as shown in FIG. 1, the electromagnetic spill valve M2 is driven to close (M4).
Pumps fuel to the fuel injection valve of the Seki M1
Start fuel injection by opening fuel injection valve based on pressure
On the other hand, the electromagnetic spill valve M2 is opened (M4)
Close the fuel injection valve by reducing the pumping pressure
Abnormality of the fuel injection device M3 for terminating fuel injection
In the diagnostic device, the fuel pressure to the fuel injection valve is detected.
Detecting means M5 and the fuel associated with the opening of the electromagnetic spill valve M2.
When the fuel pressure is reduced, the rate of decrease in the fuel pressure is
Fuel injection ends when the timing changes according to the closing action of the injection valve
A judgment means M6 for judging a timing; and an electromagnetic spill valve M2.
When the valve opening drive is commanded and the fuel injection determined as described above
Calculating means M7 for calculating a difference from the end time;
When the difference is equal to or greater than a predetermined determination value, the fuel injection device M
3 is provided with a diagnostic means M8 for diagnosing abnormality.
I have to. In the invention described in claim 2,
Item 1. The abnormality diagnosis device for a fuel injection device according to Item 1,
The diagnosing means includes a first determination value as the determination value and the first determination value.
And a second determination value larger than the value.
The difference calculated by the diagnostic means is equal to or greater than the first determination value.
And it is determined that the abnormality is less than the second determination value.
The first fail-safe that hasten the opening timing of the electromagnetic spill valve
The difference calculated by the diagnosis means is the second
The fuel injection device is
Second fail-safe for forcibly stopping the pumping of the fuel
Means.

[0009]

According to the configuration described in claim 1, the electromagnetic spill valve is
When the fuel pressure decreases as the valve opens, the fuel pressure
When the pressure reduction rate changes according to the closing action of the fuel injection valve
Is determined as the fuel injection end time.
Not only malfunction of the electromagnetic spill valve, but also
The actual end timing of fuel injection corresponding to changes in valve opening characteristics
In addition, it will be judged with high accuracy. And this fuel
Between the fuel injection end timing and the electromagnetic spill valve opening drive timing
Since the abnormality of the fuel injection device is diagnosed based on the
The cutoff result is also accurate according to the actual fuel injection behavior.
You.

According to the second aspect of the present invention, the above operation
Fuel injection timing and solenoid spill valve opening drive
When the difference from the fuel injection period is small, in other words,
When the degree of abnormality is small, the target amount of fuel injection
Engine power is minimized by reducing
On the other hand, when the degree of abnormality is large, the fuel
Engine operation is stopped by forcibly stopping pumping.
Will be able to

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which an abnormality diagnosis device for a fuel injection device 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. A fuel injection pump 1 constituting a fuel injection device includes a drive pulley 2, and the drive pulley 2 is drivingly connected to a crankshaft 40 of a diesel engine 3 as an internal combustion engine via a belt or the like. Then, the drive pulley 2 is rotationally driven by the crankshaft 40 to drive the fuel injection pump 1, whereby each cylinder of the diesel engine 3 (here, four cylinders are provided).
The fuel is pressure-fed to a fuel injection nozzle 4 provided for each of the fuel injection nozzles 4 through a fuel pipe 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, a fuel pressure P equal to or higher than a predetermined level is applied to the fuel injection nozzle 4 by the fuel pumped from the fuel injection pump 1 so that the fuel
The fuel is injected from the engine 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 urged by a spring 11 so as to engage with the cam roller 10.

A base end of a plunger 12 for pressurizing fuel 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.

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, fuel is introduced from the fuel chamber 21 into the high-pressure chamber 15 by one of the suction grooves 16 communicating with the suction port 19. on the other hand,
In the compression stroke in which the plunger 12 moves forward and the high-pressure chamber 15 is pressurized, the 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. In the middle of the spill passage 22, there is provided an electromagnetic spill valve 2 as an electromagnetic valve.
3 are provided. 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, and the coil 2
When the power supply 4 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 spilled to the fuel chamber 21. 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, when the electromagnetic spill valve 23 is turned on and off by energization, 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. Further, during the forward movement of the plunger 12, the opening timing of the electromagnetic spill valve 23 is controlled, so that the end timing of the fuel injection from the fuel injection nozzle 4,
That is, the fuel injection end timing is adjusted, and the fuel injection amount to the cylinder is controlled.

In this embodiment, the pump housing 1
3 is provided with a fuel cut valve 36 which is an electromagnetic valve for opening and closing the suction port 19. When the fuel cut valve 36 is closed, the suction port 19 is closed, and the introduction of fuel from the fuel chamber 21 to the high-pressure chamber 15 is shut off. This fuel cut valve 36 is normally connected to the plunger 12.
Is opened in the suction stroke in which the valve is returned, and closed in other strokes. Further, the fuel cut valve 36 is normally closed, as necessary, in order to cut off the pumping of the fuel from the fuel injection pump 1, that is, to perform a fuel cut.

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.

The fuel pressure in the fuel injection pump 1 is used as the control oil pressure of the timer device 26. To adjust the fuel pressure, the timer device 26 is provided with a timer control valve (TCV) 33. That is, a communication passage 34 is provided between the pressurizing chamber 30 and the low-pressure chamber 29 of the timer housing 27, and a TCV 33 is provided in the middle of the communication passage 34. The TCV 33 is an electromagnetic valve whose opening and closing are controlled by a duty-controlled energization signal. The TCV 33 is controlled to open and close to adjust the fuel pressure in the pressurizing chamber 30. Then, by adjusting the fuel pressure, the reciprocating timing of the plunger 12 is controlled, whereby the fuel injection timing from the fuel injection nozzle 4 is controlled to be advanced or retarded.

At 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. .

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. Further, 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 fuel injection nozzle 4, that is, the fuel pressure P, and outputs a signal corresponding to the magnitude of the detected value.

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, when the intake air is pressurized, 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. Further, by opening and closing the waste gate valve 54, the pressure increase level of the intake air by the turbocharger 51 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 depression of an accelerator pedal 60. In the intake passage 49,
A bypass passage 61 is provided alongside the throttle valve 59, 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.

In the vehicle of this embodiment, a warning lamp 66 is provided at the driver's seat to turn on the fuel injection pump 1 to notify the driver of the abnormality. The warning lamp 66 is controlled to be turned on as a result of an abnormality diagnosis described later.

The above-described electromagnetic spill valve 23, TCV3
3, fuel cut valve 36, glow plug 46, EVRV5
8. Each of the VSVs 64 and 65 and the warning lamp 66 are electrically connected to an electronic control unit (hereinafter simply referred to as "ECU") 71, respectively. And each of these members 23, 3
The drive timing of 3, 36, 46, 58, 64, 65, 66 is controlled by the ECU 71.

As sensors for detecting the operating state of the diesel engine 3, in addition to the rotation speed sensor 35 described above, the following various sensors are provided. That is, near the air cleaner 67 provided at the inlet of the intake passage 49, an intake air temperature sensor 72 that detects the intake air temperature THA and outputs a signal corresponding to the magnitude of the detected value is provided. In the vicinity of the throttle valve 59, the valve 5
An accelerator sensor 73 that detects an accelerator opening ACCP corresponding to the engine load from the open / close position 9 and outputs a signal corresponding to the magnitude of the detected value. 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, a water temperature sensor 7 for detecting the temperature of the cooling water of the diesel engine 3, that is, the cooling water temperature THW, and outputting a signal corresponding to the magnitude of the detected value.
5 are 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, and outputting a signal corresponding to the rotation position is provided. Further, a transmission (not shown) is provided with a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SPD. The vehicle speed sensor 77 includes a magnet 77a rotated by an output shaft of the transmission. When the reed switch 77b is periodically turned on by the magnet 77a, a pulse signal corresponding to the vehicle speed SPD is output.

In this embodiment, the ECU 71 comprises drive control means, injection end timing determination means, end timing difference calculation means, and abnormality diagnosis means.
Are connected to the above-described sensors 72 to 77, respectively, and the rotation speed sensor 35 and the pressure sensor 47 are connected to the respective sensors. In addition, the ECU 71 controls each of the sensors 35 and 4.
7, the electromagnetic spill valve 23, the TCV 33, the fuel cut valve 36, the glow plug 46, the EVRV 58, the VSVs 64 and 65, the warning lamp 66, and the like are suitably controlled based on the signals output from 7, 72 to 77.

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 and pressure sensor 47.
9, 90, 91, 92, multiplexer 94 and A / D
It is connected via a converter 95. Similarly, the input port 85 is connected to the above-described rotation speed sensor 35, crank angle sensor 76, and vehicle speed sensor 77 via a waveform shaping circuit 96. Then, the CPU 81 controls each of the sensors 35, 47, 72 to 7 input through the input port 85.
7 are read as input values.
The output ports 86 are connected to the respective driving circuits 97, 98, 99,
The electromagnetic spill valve 23, the TCV 33, the fuel cut valve 36, the glow plug 46, the EVRV 58, the VSVs 64 and 65, the warning lamp 66, and the like are connected through 100, 101, 102, 103, and 104. And the CPU 81
Are based on the input values read from the sensors 35, 47, 72 to 77, based on the electromagnetic spill valve 23, TCV 33, fuel cut valve 36, glow plug 46, EVRV 58, and VSV
64, 65, the warning lamp 66, etc. are suitably controlled.

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, the processing operation of the fuel injection amount control executed by the aforementioned ECU 71 and the processing operation for diagnosing abnormality of the fuel injection pump 1 will be described with reference to FIGS.

FIG. 6 is a flowchart showing the contents of a "fuel injection amount control routine" for controlling the fuel injection amount, among the processes executed by the ECU 71, and is periodically executed at predetermined intervals. .

When the process proceeds to this routine, first, at step 110, the engine speed NE and the supercharging pressure P are determined based on various signals from the rotation speed sensor 35, the accelerator sensor 73, the intake pressure sensor 74, the water temperature sensor 75, and the like.
iM, cooling water temperature THW, accelerator opening ACCP, etc. are read.

Subsequently, at step 120, 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 130, the basic injection amount Qb obtained this time based on the current cooling water temperature THW, the supercharging pressure PiM, etc.
Is calculated to obtain the target injection amount Q. That is, the target injection amount Q is obtained by correcting the basic injection amount Qb according to the cold state or the operating state of the turbocharger 51.

Then, in step 140, fuel injection is executed based on the target injection amount Q obtained this time. That is, by controlling the electromagnetic spill valve 23 based on the target injection amount Q, the pressure of the fuel from the fuel injection pump 1 to the fuel injection nozzle 4 is controlled. Thereby, the fuel injection amount from the fuel injection nozzle 4 is controlled. For more information,
After the electromagnetic spill valve 23 is turned on (closed) before the compression stroke of the plunger 12, the time at which the electromagnetic spill valve 23 should be turned off (opened) at the end of fuel injection is determined as the injection end set time tes. . At this time tes,
It is determined by converting the fuel injection amount Q into time. Then, by actually turning off (opening) the electromagnetic spill valve 23 based on the injection end set time tes, the fuel pumping from the fuel injection pump 1 is ended in one fuel injection. After ending the processing of step 140, the subsequent processing is temporarily ended.

Next, a series of processing operations for diagnosing abnormality of the fuel injection pump 1 will be described. FIG. 7 shows the ECU 71.
6 is a flowchart showing the processing contents of a “subroutine” which is measured by the timer function of the CPU 81 and executed at each time ti among the processing executed by the CPU 81.

When the process proceeds to this routine, first, at step 210, the fuel pressure P is sampled based on the signal from the pressure sensor 47. Subsequently, in step 220, the fuel pressure Pi at the time ti at that time is calculated.

Next, at step 230, 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. Step 2
At 40, the fuel pressure Pi at that time ti
The second differential value (d ² Pi / dti ² ) is calculated.

In step 250, 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, every 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. 8 and 9 are flowcharts showing the contents of the "te calculation routine" for calculating the injection end time te and the like used for abnormality diagnosis, among the processes executed by the ECU 71. The processing of this routine is executed every time one fuel injection is performed.

When the process proceeds to this routine, first, at step 310, 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 320, 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 310 and repeats the processes of steps 310 and 320.
If it is determined in step 320 that the fuel pressure Pi is higher than the previous fuel pressure P (i-1), the process proceeds to step 330 assuming that the fuel pressure P is in the process of increasing.

At step 330, 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 310 and repeats the processing of steps 310 to 330. Step 33
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 to be increased and fuel injection P is to be started. Move to.

Then, in step 340, 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 350, it is determined whether or not the currently read second derivative (d ² Pi / dti ² ) 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 process jumps to step 340. Step 350 is repeated. In contrast, in step 350, 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 360.

Then, at step 360, 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 340 and repeats the processing of steps 340 to 360. Step 36
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 370 on the assumption that the change in the fuel pressure P has definitely decreased.

In step 370, 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 surely 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 380, at the time ti when the one-time differential value (dPi / dti) becomes “0” in the retrieved calculation data, the time ti is set to the time of 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.

Subsequently, at step 390, 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 400, it is determined whether or not the fuel pressure Pi read this time is smaller than the injection start pressure Ps obtained in step 380. If the fuel pressure Pi is not lower than the injection start pressure Ps, the routine jumps to step 390, where step 39 is executed.
Each process of 0,400 is repeated. If it is determined in step 400 that the fuel pressure Pi is lower than the injection start pressure Ps, the process proceeds to step 410.

In step 410, it is determined whether or not the fuel pressure Pi corresponding to the 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 390 and repeats the processes of steps 390 to 410. or,
In step 410, when the fuel pressure Pi is lower than the previous fuel pressure P (i-1), the fuel pressure P decreases 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 420.

In step 420, 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 43
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 440.

In step 440, 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 450, the first differential 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 440. Steps 440 and 450 are repeated. In contrast, in step 450,
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 460.

In step 460, 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 470, 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 Does not change from the increasing process to the decreasing process, the process jumps to step 460 and proceeds to step 46.
The process of 0,470 is repeated. Step 4
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 480.

In step 480, the time ti at which the first derivative (dPi / dti) becomes larger than the threshold value d4 in the immediately preceding step 470 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.
The fuel pressure Pi at the point “P” is set as the injection end pressure Pe. 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.

When the process of step 480 is completed, the subsequent processes are temporarily terminated, and the process from step 310 is started again after waiting for the next fuel injection. Therefore, according to the processing of the above “te calculation routine”, every 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, an example of the behavior of the injection start time ts, the injection end time te, the fuel pressure P and its one-time differential value (dPi / dti) obtained as described above will be described with reference to the time chart of FIG. explain. When the plunger 12 of the fuel injection pump 1 starts to move forward when fuel is injected from the fuel injection nozzle 4, FIG.
As shown in the figure, at time t1, the fuel pressure P starts to increase. Then, the fuel pressure P gradually increases as the plunger 12 moves forward. 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, the one-time differential value (dP / d
When t) exceeds the plus threshold value d1 for the reference time T1, the ECU 71 determines that the fuel pressure P is in the process of increasing the fuel pressure P to start fuel injection.

Thereafter, at time t2, when the increasing fuel pressure P undergoes a large inflection, its one-time differential value (dP / d
t) falls greatly. Then, immediately after the time t2, when the first derivative (dP / dt) falls below the negative threshold value d2 and the reference time T2 elapses, the ECU 71 sets the fuel pressure P due to the start of fuel injection. It is determined that the change rate has definitely decreased. 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. 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. That is, as shown in FIG.
Is determined, the injection end time te corresponding to the inflection point B at which the decrease once stops decreasing and the injection end pressure Pe at that time are obtained. The period from the injection start time ts to the injection end time te is an injection period in which the fuel injection is actually performed.

Next, the abnormality diagnosis of the fuel injection pump 1 performed using the injection end time te obtained as described above will be described. FIG. 11 is a flowchart showing the processing content of an “abnormality diagnosis routine” executed by the ECU 71, which is periodically executed at predetermined intervals.

When the process proceeds to this routine, first, at step 500, the engine speed N obtained from the engine speed sensor 35, the accelerator sensor 73, and the like.
E and the accelerator opening ACCP are read.

Subsequently, at step 510, it is determined whether or not a condition for performing the abnormality diagnosis of the fuel injection pump 1 is satisfied. This determination is made based on the currently read engine speed NE and accelerator opening ACCP. That is, the determination is made based on whether the diesel engine 3 is in the idling state where the change in the engine speed NE is small or the engine is in a steady operation state after the start of the diesel engine 3 is completed. Here, if the abnormality diagnosis condition is not satisfied, the subsequent processing is temporarily terminated without performing the abnormality diagnosis. On the other hand, when the abnormality diagnosis condition is satisfied, the process proceeds to step 520 to perform the abnormality diagnosis.

In step 520, the injection termination set time tes determined at the time of the previous fuel injection in the processing of the aforementioned "fuel injection amount control routine" is read. That is, the latest injection end set time tes determined as the command timing for turning off (opening) the electromagnetic spill valve 23 is read.

In step 530, the latest injection end time te obtained at the time of the previous fuel injection in the processing of the above-mentioned "te calculation routine" is read. That is,
The injection end time te corresponding to the fuel injection end timing actually obtained from the waveform of the fuel pressure P is read.

Further, in step 540, a region of the delay time Td corresponding to the currently read engine speed NE is calculated. The delay time Td is set for a time that can allow a delay of the injection end time te, and is obtained by referring to a predetermined map as shown in FIG.

Next, at step 550, the injection end time te and the injection end set time tes which are read this time.
Is calculated, and the calculation result is set as the injection end time difference ΔT. That is, as shown in the time chart of FIG. 13, at the end of the fuel injection, the electromagnetic spill valve 23 was turned off (opened) by the injection end time te actually obtained from the waveform of the fuel pressure P and the command of the ECU 71. The difference from the injection end set time tes at this time is obtained as the injection end time difference ΔT.

Then, in step 560, the region of the delay time Td obtained this time is compared with the injection end time difference ΔT. Here, when the current injection end time difference ΔT is sufficiently small and included in the “normal” area in the map of FIG. 12, it is diagnosed that the fuel injection pump 1 is normal, and the subsequent The process ends once.

On the other hand, in step 560, when the injection end time difference ΔT is slightly large and is included in the “abnormal small” area in the map of FIG.
Step 3 diagnoses that the fuel injection pump 1 is a little abnormal because of a slight difficulty in moving for some reason.
Move to 70. Then, in step 570, the warning lamp 66 is turned on. Further, in step 580, the fuel injection amount is reduced. That is, in order to uniformly reduce the fuel injection amount corresponding to the target injection amount Q,
That is, the control for uniformly advancing the injection end set time tes is executed. Then, after the processing of step 580 is completed, the subsequent processing is temporarily ended.

Alternatively, in step 560, when the injection end time difference ΔT is very large and is included in the area of “abnormal large” in the map of FIG. 12, the electromagnetic spill valve 23 does not move for some reason. In step 590, it is diagnosed that the abnormality of the fuel injection pump 1 is large.
Move to. Then, in step 590, the warning lamp 66 is turned on. Also, in step 600,
In order to cut off the pumping of fuel from the fuel injection pump 1,
The fuel cut valve 36 is closed, and the subsequent processing is temporarily terminated.

Therefore, according to the above-described "abnormality diagnosis routine", it is determined whether or not the electromagnetic spill valve 23 has failed every time one fuel injection is performed. If the electromagnetic spill valve 23 is out of order, the fuel injection pump 1 is diagnosed as abnormal, the warning lamp 66 is turned on, and a measure is taken according to the degree of the abnormality.

As described above, according to the abnormality diagnosis apparatus of this embodiment, the injection end set time tes is determined from the target injection amount Q when performing one fuel injection.
At the timing synchronized with the injection end set time tes, the electromagnetic spill valve 23 is controlled to be switched from the on (closed) state to the off (open) state. As a result, the end of the pressure feeding of the fuel from the fuel injection pump 1 to the fuel injection nozzle 4 is controlled, and the fuel injection amount supplied to the diesel engine 2 is controlled. At this time, the pressure of the fuel pumped from the fuel injection pump 1, that is, the fuel pressure P is actually detected by the pressure sensor 47. Then, based on the change state of the fuel pressure P, the actual injection end time te in the fuel injection pump 1 is obtained. That is, based on the waveform change of the fuel pressure P, the actual injection end time te corresponding to the actual valve opening timing of the electromagnetic spill valve 23 is obtained. Further, the injection end set time te at which the electromagnetic spill valve 23 should be turned off (opened)
The difference between s and the actual injection end time te is determined as the injection end time difference ΔT. That is, the difference between the target valve opening timing of the electromagnetic spill valve 23 and the actual injection end time te is calculated. When the injection end time difference ΔT is larger than necessary than the preset delay time Td,
It is diagnosed that the fuel injection pump 1 is abnormal due to various failures of the electromagnetic spill valve 23, and the warning lamp 66 is turned on. Further, when the abnormality determined from the magnitude of the injection end time difference ΔT is mild, the fuel injection amount is reduced as fail-safe control. Alternatively, the injection end time difference Δ
If the abnormality determined from the size of T is significant,
The fuel cut is executed as a fail safe, and the fuel pumping from the fuel injection pump 1 to the diesel engine 3 is performed.

Therefore, according to this embodiment, when the electromagnetic spill valve 23 does not move as intended for some reason, the injection end time te obtained from the change state of the fuel pressure P waveform greatly changes. become. Therefore, abnormality of the fuel injection pump 1 due to various failures of the electromagnetic spill valve 23 is diagnosed based on the injection end time difference ΔT. As a result, not only an abnormality caused by an electrical failure of the electromagnetic spill valve 23 but also an abnormality caused by a mechanical failure of the electromagnetic spill valve 23 can be diagnosed. That is, in the event that the electromagnetic spill valve 23 malfunctions due to an electrical system failure such as a disconnection or short circuit of the electromagnetic spill valve 23 or a failure of the drive circuit 97 in the ECU 71,
The abnormality can be reliably diagnosed. At the same time, even if the valve element 24 of the electromagnetic spill valve 23 becomes difficult to move or the valve element 24 sticks in a closed state due to deterioration of fuel properties or biting of foreign matter, etc. The abnormality can be reliably diagnosed.

Further, according to this embodiment, the degree of abnormality is distinguished based on the actual fuel injection based on the difference in the injection end time difference ΔT. That is, instead of simply monitoring (detecting) the mechanical failure of the electromagnetic spill valve 23 directly to diagnose the abnormality, the degree of the abnormality is finely evaluated from the waveform of the fuel pressure P in accordance with the actual fuel injection. ing. As a result, the abnormality of the fuel injection pump 1 can be accurately diagnosed in accordance with the actual fuel injection behavior. That is, it is possible to accurately diagnose whether the fuel injection pump 1 is normal or whether the degree of abnormality is slight or serious based on actual fuel injection.

According to this embodiment, from the result of the above-described abnormality diagnosis, it is possible to achieve an appropriate fail-safe according to the degree of the abnormality. Specifically, by turning on the warning lamp 66 in response to the abnormality, the occurrence of the abnormality can be immediately notified to the driver. In addition, when the abnormality is mild, since the fuel injection amount is reduced as a fail-safe control, it is necessary to move the vehicle to the nearest shelter or repair place while operating the diesel engine 3 at low speed. Can be. Similarly, when the abnormality is serious, the fuel cut is performed as a fail-safe, so that the diesel engine 3 can be stopped, and the diesel engine 3 is prevented from operating at an unnecessarily high speed. can do.

Further, in this embodiment, a more specific study is made on how to obtain the actual injection end time te. That is, in this embodiment, the waveform of the fuel pressure P obtained from the pressure sensor 47 provided in each fuel injection nozzle 4 is monitored. Then, when the fuel pressure P is in the process of decreasing in a range lower than the injection start pressure Ps,
Based on the first derivative (dPi / dti), a time point at which the rate of decrease of the fuel pressure P changes from an increasing process to a once decreasing process is obtained. Here, it is confirmed that the point where the decreasing rate of the fuel pressure P changes from the increasing process to the decreasing process once corresponds to a portion where the decrease in the fuel pressure P temporarily stops decreasing when the fuel injection nozzle 4 is closed. ing. That is, in the waveform pattern shown in FIGS. 10A and 10B, in the process of decreasing the fuel pressure P, the point in time at which the decreasing rate of the fuel pressure P changes from the increasing process to the decreasing process is as follows. It has been confirmed that this means an inflection point B when the fuel pressure P stops decreasing for a moment.

Therefore, the actual injection end time te is specifically specified as the inflection point B of the fuel pressure P,
The injection end time te is obtained by excluding the effects of the fuel injection nozzle 4 over time, the individual difference, and the noise. As a result, the injection end time te can be accurately obtained without being affected by changes over time, individual differences, noise, and the like of the fuel injection nozzle 4. From this point of view, the injection end time difference ΔT for the above-described abnormality diagnosis can be more accurately obtained, and the reliability of the abnormality diagnosis can be improved.

The present invention is not limited to the above-described embodiment, but 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 pressure sensor 47 is provided for each fuel injection nozzle 4 of each cylinder. However, the pressure sensor may be provided in the middle of a fuel pipe leading to each fuel injection nozzle.

(2) In the above embodiment, the pressure sensors 47 are provided at the fuel injection nozzles 4 of the respective cylinders so as to detect the fuel pressure P applied to the fuel injection nozzles 4 respectively. May be provided in the fuel injection pump to detect the fuel pressure P in the plunger high pressure chamber. In this case, only one pressure sensor needs to be used, and the number of components can be reduced.

(3) In the above-described embodiment, the abnormality diagnosis device is embodied in the electronically controlled diesel engine of the automobile. However, similarly, the high pressure gasoline injection in which the fuel injection amount from the fuel injection device is controlled by the solenoid valve. It can also be embodied in an expression engine or the like.

(4) In the above embodiment, the injection end time te
Although the injection start pressure Ps used for determining the injection start pressure Ps is determined in accordance with the actually obtained injection start time ts, a reference value experimentally determined in advance may be used as the injection start pressure Ps.

(5) In the above embodiment, the fuel injection amount reduction control and the fuel cut are performed as fail-safe according to the degree of abnormality to be diagnosed. However, only the fuel cut is performed regardless of the degree of abnormality. This may be concretely performed when performing. Alternatively, instead of controlling the fuel injection amount corresponding to the target injection amount Q to decrease, the fuel injection amount may be fixed to a predetermined small injection amount.

(6) In the above embodiment, the fuel injection pump 1
Is diagnosed as abnormal, the warning lamp 66 is turned on to notify the driver of the abnormality. However, the warning lamp 66 is turned on, and the result of the abnormality diagnosis is recorded in the backup RAM 84. It may be. In this case, by reading the recorded data in the backup RAM 84 as needed, the past history of the occurrence of the abnormality can be known later.

[0092]

As described in detail above, according to the first aspect,
According to the invention, not only the malfunction of the electromagnetic spill valve,
Actual fuel injection that responds to changes in valve opening characteristics of the fuel injector
The end time can be determined with extremely high accuracy.
Difference between fuel injection end timing and electromagnetic spill valve opening drive timing
The electrical and mechanical failure of the electromagnetic spill valve based on
Abnormalities caused by malfunctions or fuel injector malfunctions.
Diagnosis can be made accurately in accordance with the actual fuel injection behavior.
I will be able to.

According to the second aspect of the present invention,
In addition to the above effects, an accurate fail depending on the degree of abnormality
Safe processing can be executed.

[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 cross-sectional view illustrating a distribution type fuel injection pump according to 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 illustrating a configuration of an ECU according to one embodiment.

FIG. 6 is a flowchart showing the processing content of a “fuel injection amount control routine” executed by an ECU in one embodiment.

FIG. 7 is a flowchart showing the processing content of a “subroutine” executed by the ECU in one embodiment.

FIG. 8 is a flowchart illustrating the processing content of a “te calculation routine” executed by the ECU in one embodiment.

FIG. 9 is a flowchart showing the continuation of the processing content of the “te calculation routine” in one embodiment.

FIG. 10 is a time chart illustrating behaviors of an injection start time, an injection end time, a fuel pressure, and a one-time differential value obtained in one fuel injection in one embodiment.

FIG. 11 is a flowchart showing the processing content of an “abnormality diagnosis routine” executed by the ECU in one embodiment.

FIG. 12 is a map in which the relationship between the engine rotation speed and the delay time is determined in advance and is used for abnormality diagnosis.

FIG. 13 is a time chart illustrating the relationship between the fuel pressure and the ON / OFF behavior of the electromagnetic spill valve during one fuel injection, and the relationship between the set injection end time and the actual injection end time in one embodiment. is there.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump as a fuel injection device, 3 ... Diesel engine as an internal combustion engine, 4 ... Fuel injection nozzle,
23: an electromagnetic spill valve as an electromagnetic valve; 47, a pressure sensor as a fuel pressure detecting means; 71, an ECU constituting drive control means, injection end timing determining means, end timing difference calculating means, and abnormality diagnosis means.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁶ , DB name) F02D 41/22 380 F02M 65/00 301

Claims (2)

(57) [Claims] An electromagnetic spill valve is driven to close and an internal combustion engine is operated.
The fuel is pumped to the fuel injection valve, and the fuel is fed based on the fuel pressure.
Then, the fuel injection valve is opened to start fuel injection.
Drive the electromagnetic spill valve to reduce the fuel pressure
To close the fuel injection valve and terminate fuel injection.
The fuel injector abnormality diagnosis device
Te, a detecting means for detecting a fuel pumping pressure to the fuel injection valve, the fuel delivery pressure with the opening of the electromagnetic spill valve is reduced
When the fuel injection pressure decreases, the rate of decrease of the fuel pressure
The timing that changes according to the valve operation is the fuel injection end timing.
Determining means for determining, a timing at which the valve opening drive of the electromagnetic spill valve is commanded, and the determination
Calculation means for calculating the difference from the fuel injection end timing to be cut off
And when the calculated difference is equal to or greater than a predetermined determination value,
Diagnostic means for diagnosing that the fuel injection device is abnormal. 2. An abnormality of the fuel injection device according to claim 1.
In the diagnostic device, the diagnostic means includes:
A first determination value and a second determination greater than the first determination value
And the difference calculated by the diagnostic means is the first determination value.
Abnormality diagnosis if it is more than and less than the second determination value
The opening timing of the electromagnetic spill valve when
The difference calculated by the first fail-safe means and the diagnostic means is the second judgment.
When an abnormality is diagnosed as being equal to or more than the predetermined value, the fuel injection device
Second fail-safe for forcibly stopping the pumping of the fuel
And a fuel injection device.
Abnormal diagnostic device.