JP2917734B2 - Degradation 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 having a fuel injection pump and a fuel injection nozzle for injecting fuel into an internal combustion engine, and more particularly to diagnosing deterioration of the fuel injection device with time. The present invention relates to a deterioration diagnosis device for a vehicle.

[0002]

2. Description of the Related Art Conventionally, as an internal combustion engine provided with a fuel injection device including a fuel injection pump, a fuel injection nozzle, and the like, for example, a diesel engine, a high-pressure gasoline injection engine, and the like are given. In such an internal combustion engine, it is very important to control the amount of fuel injected from the fuel injection device to a target value, particularly from the viewpoint of recent exhaust gas regulations.

For example, in a fuel injection device of an electronically controlled diesel engine, in a fuel injection pump, fuel in a high pressure chamber is pressure-fed by a lift of a plunger and injected from a fuel injection nozzle into each cylinder of the diesel engine. 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 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. Alternatively, a timer device provided in the fuel injection pump is drive-controlled so that the fuel injection timing becomes a target injection timing determined according to the operating state of the engine. With this control, the reciprocating timing of the plunger is adjusted, and the timing of pumping fuel from the fuel injection pump to the fuel injection nozzle, and consequently, the fuel injection timing at the fuel injection nozzle is controlled to be retarded or advanced. .

[0004] However, even with this type of fuel injection device, there is a possibility that the control characteristics of the fuel injection amount and the fuel injection timing may change due to the deterioration over time of the fuel injection pump and the fuel injection nozzle. For example, in a fuel injection pump,
When wear occurs in the cam mechanism that reciprocates the plunger,
As a result, the amount of lift of the plunger changes. Therefore, there is a possibility that the injection amount from the fuel injection nozzle may be larger than the expected injection amount. Also, in the fuel injection nozzle, when the urging force of the pressure setting spring decreases, the valve opening pressure of the fuel injection nozzle drops below the set pressure, so that the injection amount from the fuel injection nozzle increases or the injection timing advances. There was a risk of shifting to the corner side.

Therefore, a technique for coping with the above-mentioned problem has been disclosed by the present applicant in Japanese Patent Application Laid-Open No. Sho 62-210.
No. 242 publication. In this prior art, the aim is to achieve good fuel injection timing control in response to the deterioration with time of the valve opening pressure in the fuel injection nozzle with high accuracy. Therefore, when the diesel engine is idling, idle speed control (ISC) for setting the idle speed to a required target speed is executed.
That is, a control value (ISC control value) corresponding to the nozzle opening time for obtaining the fuel injection amount necessary for the idle speed control is calculated. Further, the change amount of the ISC control value is calculated, and the fuel injection timing other than at the time of idling is corrected according to the change amount. That is, in this conventional technique, the fuel injection timing is corrected according to the amount of change in the ISC control value, assuming that the deterioration over time of the fuel injection nozzle is reflected in the ISC control value.

[0006]

However, in the prior art, the ISC control value reflects the deterioration with time of the fuel injection nozzle. However, the ISC control value is actually changed to the ISC control value of the fuel injection device. It is known that friction loss of an engine is reflected in addition to deterioration with time. Also IS
It has also been confirmed that whether or not deterioration over time or friction loss is reflected in the C control value changes depending on the cumulative operating time of the engine.

That is, the graph of FIG. 10 shows the relationship between the cumulative use time of the engine and the fuel injection amount during idling. In this graph, the change in the actual fuel injection amount (actual injection amount) is indicated by a solid line, and the change in the ISC control value converted to the injection amount is indicated by a broken line. here,
The actual injection amount and the ISC control value at the start of use are each a predetermined value Q1. Then, the actual injection amount and IS
The C control value tends to decrease equally as the use time elapses. Further, when the use time reaches a certain reference time T1, the actual injection amount is substantially settled to the predetermined value Q2, and the actual injection amount tends to further decrease with the ISC control value as the use time elapses thereafter. This is because the actual injection amount changes by reflecting only the friction loss, and the change in the friction loss disappears at the reference time T1. That is, it means that the running-in operation of the engine is completed at the reference time T1. Before the running-in operation is completed, the difference between the predetermined value Q1 and the predetermined value Q2 means the magnitude of the friction loss. Also, there is no aging deterioration before the running-in operation is completed.
The SC control value changes in the same manner as the actual injection amount by reflecting only the friction loss. On the other hand, after time T1, since the running-in operation of the engine has been completed, I
The SC control value changes by reflecting only the deterioration over time.

[0008] Therefore, in the prior art, the fuel injection timing is corrected in accordance with the amount of change in the ISC control value regardless of whether or not the running-in operation is completed. Therefore, there is a problem that before the completion of the running-in operation, the fuel injection timing is unnecessarily corrected on the assumption that there is deterioration with time even though there is no deterioration with time. That is, in the related art, the aging deterioration of the fuel injection device is erroneously diagnosed, and correction for dealing with the aging deterioration is erroneously performed.

Here, in order to cope with the deterioration with time of the fuel injection device, in addition to correcting the fuel injection timing as described above, the fuel injection amount is corrected, and the driver is notified of abnormal deterioration with time. Various methods, such as giving a warning, can be considered. Therefore, it is necessary to accurately diagnose the aging deterioration of the fuel injection device in order to appropriately perform these measures. Moreover, it is desired that the diagnosis can be made with a simple configuration without complicating the configuration of the device.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide an apparatus for diagnosing deterioration with time of a fuel injection device which can accurately and easily diagnose deterioration with time of the fuel injection device. Is to do.

[0011]

In order to achieve the above object, according to the present invention, as shown in FIG. 1, a valve is opened by obtaining a fuel pressure higher than a predetermined level, and fuel is injected into an internal combustion engine M1. A fuel injection device M4 including a fuel injection nozzle M2 for performing the fuel injection and a fuel injection pump M3 that is driven and controlled to pump the fuel to the fuel injection nozzle M2 for detecting the rotation speed of the internal combustion engine M1. A control value relating to the fuel injection amount, such that the idling speed detected by the speed detecting device M5 becomes a required target speed when the internal combustion engine M1 is idling; RPM feedback control means M6 for feedback controlling the drive of fuel injection pump M3 based on
If, on the basis of the change in the control value determined by the idle speed feedback control means M6, the time degradation diagnosis means M7 for diagnosing aging of the fuel injection device M4, Do shown
The accumulated use amount of the internal combustion engine M1 stored in the storage means is used to determine that the running-in operation of the internal combustion engine M1 has been completed.
When the following reference value, and a cross-sectional inhibiting means M8 examination you prohibit the diagnosis of deterioration over time due to aging deterioration diagnosis means M7.
The cumulative use amount is the cumulative use amount of the internal combustion engine M1.
The cumulative mileage of the vehicle equipped with the internal combustion engine M1, or
Of an alternative value that changes with the cumulative use time of the internal combustion engine M1
It is preferable to use either.

[0012]

According to the above arrangement, as shown in FIG. 1, the fuel is pumped to the fuel injection nozzle M2 by controlling the driving of the fuel injection pump M3. Then, the fuel is injected into the internal combustion engine M1 by opening the valve by obtaining the fuel pressure of the predetermined level or more from the fuel injection nozzle M2. Here, in the idle speed feedback control means M6, the internal combustion engine M
1 at the time of idling, a control value is determined so that the idle speed detected by the speed detecting means M5 becomes a required target speed, and the fuel injection pump M is determined based on the control value.
3 is feedback-controlled. Then, the aging deterioration diagnosis means M7 diagnoses the aging deterioration of the fuel injection device M4 including the fuel injection nozzle M2 and the fuel injection pump M3 based on the change of the control value determined as described above. That is, the control value obtained during the idle speed control is changed to the fuel injection device M
As a result, the deterioration with time is diagnosed based on the change in the control value. Also stored in storage means
When the used cumulative amount of the used internal combustion engine M1 is equal to or less than the reference value
Indicates that the running-in operation of the internal combustion engine M1 has not been completed.
Thus, the diagnosis of deterioration with time by the deterioration diagnosis means M7 is prohibited by the diagnosis prohibition means M8.

Therefore, until the running-in operation of the internal combustion engine M1 is completed, that is, while the deterioration of the fuel injection device M4 with time is small, even if the control value changes with the change in the friction loss of the internal combustion engine M1, The aging of the fuel injection device M4 is not erroneously diagnosed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the deterioration 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. The fuel injection pump 1 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. 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 pump 1,
A fuel injection device is constituted by the fuel injection nozzle 4, the fuel line 4a, and the like. Further, the fuel injection nozzle 4 is an automatic valve having a built-in needle valve as a valve body and a spring for adjusting the valve opening pressure of the needle valve. You. Therefore, the fuel injection pump 1
Is supplied to the fuel injection nozzle 4 through the fuel line 4a by a fuel pressure higher than a predetermined level, 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 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 inserted 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 comprising 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.

Then, 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.

Accordingly, 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.

At the upper part of the roller ring 9, a rotation speed sensor 35 composed of an electromagnetic pickup coil as rotation speed detecting means is mounted so as to face the outer peripheral surface of the pulser 7. When the rotation speed sensor 35 crosses a projection or the like of the pulsar 7, it detects the passage of the rotation and outputs 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. Each sub-combustion chamber 45 is provided with a well-known glow plug 46 as a start-up assist device.

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 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 and the fuel injection device 4 including the fuel injection nozzle 4 to notify the driver of a deterioration abnormality. ing. The warning lamp 66 is turned on as a result of an abnormality diagnosis described later.

The above-described electromagnetic spill valve 23, TCV3
3, glow plug 46, EVRV58, each VSV64,
The electronic control unit (hereinafter simply referred to as “E”)
CU ”) 71. And each of these members 23, 33, 46, 58, 6
The drive timings of 4, 65, 66 are 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 67 provided at the entrance 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 addition, in this embodiment, the transmission is provided with a neutral switch 78. This switch 78 is turned on when the transmission is in a neutral state, and outputs a neutral signal NS instructing this. An air conditioner (not shown) is provided with an air conditioner switch 79. The switch 79 is turned on when the air conditioner is on, and outputs an air conditioner signal AS instructing the switch 79. Further, in this embodiment, an electric load switch 80 for turning on a large electric load (for example, a headlight) (not shown) other than the air conditioner is provided. When the switch 80 is turned on, it outputs an electric load signal LS for instructing this.

In this embodiment, the ECU 71 constitutes idle speed feedback control means, time degradation diagnosis means and diagnosis inhibition means. The ECU 71 includes the sensors 35, 72 to 77 and the switches 7 described above.
8 to 80 are connected respectively. Further, the ECU 71 determines the electromagnetic spill valve 23, TC based on the signals output from the sensors 35, 72 to 77 and the switches 78 to 80.
V33, glow plug 46, EVRV58, each VSV6
4, 65 and the warning lamp 66 are suitably controlled.

Next, the configuration of the ECU 71 will be described with reference to the block diagram shown in FIG. The ECU 71 includes a central processing unit (CPU) 81, a read-only memory (ROM) 8 in which a predetermined control program, a map, and the like are stored in advance.
2, a random access memory (RAM) 83 for temporarily storing the calculation results of the CPU 81, a backup RAM 84 for storing the stored data, and the like. And
The ECU 71 is configured as 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, and water temperature sensor 75 in buffers 88, 89, 90, 91, respectively.
They are connected via a multiplexer 94 and an A / D 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. Further, the input port 85 is connected to the neutral switch 78, the air conditioner switch 79, and the load switch 80 described above.
Are connected via the respective buffers 97, 98, 99. Then, the CPU 81 controls the sensors 35, 72 to 77 and the switches 78 to 77 input through the input port 85.
The signals from 80 and the like are read as input values.
The output ports 86 are connected to the respective drive circuits 100, 101, 1
02, 103, 104, 105, 106, the electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EVRV
58, VSVs 64 and 65, a warning lamp 66 and the like are connected respectively. Then, the CPU 81 controls each sensor 3
5, 72 to 77 and the input values read from the switches 78 to 80, the electromagnetic spill valve 23, the TCV 33,
Glow plug 46, EVRV58, VSV64, 65
And the warning lamp 66 and the like are suitably controlled.

The CPU 81 of this embodiment also has a timekeeping function. Further, in this embodiment, the glow plug 46 is provided for each cylinder of the diesel engine 3, but only one of them is shown in the block diagram of FIG. 4 for convenience.

Next, the processing operation for controlling the fuel injection amount executed by the ECU 71 will be described with reference to FIGS.
It will be described according to. FIG. 5 is a flowchart showing the details of the "idle injection amount control routine" for controlling the fuel injection amount during idling, among the processing operations 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, the engine speed NE, and the engine speed NE are determined based on various signals from the speed sensor 35, the accelerator sensor 73, the intake pressure sensor 74, the water temperature sensor 75, the vehicle speed sensor 77, and the like. The accelerator opening ACCP, the supercharging pressure PiM, the cooling water temperature THW, and the vehicle speed SPD are read, respectively. Further, based on various signals from the neutral switch 78, the air conditioner switch 79, the electric load switch 80, etc., the neutral signal NS, the air conditioner signal AS, the electric load signal LS, etc. are read, respectively.

Subsequently, at step 120, it is determined whether or not the diesel engine 3 is in an idle state. This determination is based on the engine speed NE and the accelerator opening A
This is performed based on the CCP, the vehicle speed SPD, the neutral signal NS, and the like. And when not in idle state,
The process proceeds to step 190, where the process proceeds to non-idling fuel injection amount control described later, and the subsequent processing is temporarily terminated.
If it is in the idle state, the process proceeds to step 130.

In step 130, it is determined whether or not the condition of idle speed control (ISC) is satisfied. That is, it is determined whether or not a condition for controlling the fuel injection amount so that the idling speed becomes the required target speed is satisfied. This determination is based on the currently read engine speed NE, accelerator opening ACCP, and coolant temperature TH.
This is performed based on W, vehicle speed SPD, neutral signal NS, air conditioner signal AS, electric load signal LS, and the like. That is, based on these various signals, the diesel engine 3
Is fully warmed up, the transmission is in neutral, the air conditioner is off, and large electrical loads are off,
When all the conditions that the change in the engine speed NE is within a predetermined value are satisfied, and such a stable state continues for a predetermined time, it is determined that the ISC condition is satisfied. Where I
If the SC condition is not satisfied, the process proceeds to step 140 to perform normal idle injection amount control.

In step 140, the currently read engine speed NE and accelerator opening ACC are read.
An idle injection amount Qs as a fuel injection amount required at the time of idling is calculated based on P, the cooling water temperature THW, and the like. Next, at step 150, fuel injection is executed based on the idle injection amount Qs. That is, the idle injection amount Qs
By controlling the electromagnetic spill valve 23 on the basis of the above, the fuel pumping from the fuel injection pump 1 to the fuel injection nozzle 4 is controlled, and the fuel injection amount injected from the fuel injection nozzle 4 is thereby controlled. Then, the subsequent processing ends once.

On the other hand, if the ISC condition is satisfied in step 130,
An ISC injection amount Qisc as a control value for idle speed control is calculated based on the engine speed NE and the like.

The processing contents of this calculation will be described with reference to the flowchart shown in FIG. That is, first, in step 161, the target rotation speed NF during idling is set. The target rotational speed NF is determined based on a neutral signal NS and an air conditioner signal AS as to whether the transmission is in a neutral state and whether the air conditioner is on, and a predetermined value determined in accordance with the result of the determination. Is set to

Next, at step 162, the absolute value of the difference between the actual engine speed NE and the target engine speed NF is
It is determined whether it is smaller than a predetermined reference value α. Here, if the absolute value of the difference between the engine speed NE and the target speed NF is smaller than the reference value α, in step 163, the previously obtained ISC injection amount Qisc
Is set as a new ISC injection amount Qisc.

On the other hand, in step 162, the absolute value of the difference between the engine speed NE and the target speed NF is set to the reference value α.
If not, in step 164,
The difference between the engine speed NE and the target speed NF is set as a speed difference ΔNE. In step 165, a correction injection amount Qdne is calculated based on the rotational speed deviation ΔNE. This calculation is performed as shown in FIG.
The relationship between E and the correction injection amount Qdne is performed with reference to a predetermined map.

Thereafter, in step 166, it is determined whether or not the difference between the engine speed NE and the target speed NF is larger than "0", that is, whether or not the difference is a positive number. If the difference between the engine rotational speed NE and the target rotational speed NF is a positive number, in step 167, the previous IS
Corrected injection amount Qdn obtained this time from C injection amount Qisc
e, and subtracts the result of the subtraction into a new ISC injection amount Qis.
Set as c.

If the difference between the engine speed NE and the target engine speed NF is not a positive number at step 166, then at step 168 the previous ISC injection amount Qis
The correction injection amount Qdne obtained this time is added to c, and the addition result is set as a new ISC injection amount Qisc.

In this way, the ISC injection amount Qisc for controlling the idle speed in step 160 is obtained. Then, in step 170 of FIG. 5, fuel injection is performed based on the ISC injection amount Qisc obtained this time. That is, the amount of fuel injected from the fuel injection nozzle 4 is controlled by controlling the electromagnetic spill valve 23 based on the ISC injection amount Qisc. And step 1
At 80, the ISC injection amount Qisc obtained this time is temporarily stored in the RAM 83, and the subsequent processing is temporarily ended.

That is, when the ISC condition is satisfied, the ISC injection amount Qisc is determined so that the engine speed NE actually detected by the speed sensor 35 at idling becomes the required target speed NF. . Then, feedback control (feedback control) of the electromagnetic spill valve 23 of the fuel injection pump 1 is performed based on the ISC injection amount Qisc. As a result, the amount of fuel injection that is pressure-fed from the fuel injection pump 1 to the fuel injection nozzle 4 and injected is controlled.

Next, control of the fuel injection amount during non-idling will be described. FIG. 8 is a flowchart showing the processing content of a "non-idle injection amount control routine" executed by the ECU 71, and is periodically executed at predetermined intervals.

When the processing shifts to this routine, first, at step 210, the engine speed NE, the accelerator opening ACCP based on various signals from the speed sensor 35, the accelerator sensor 73, the intake pressure sensor 74, the water temperature sensor 75 and the like. , The supercharging pressure PiM and the cooling water temperature THW are read.

Subsequently, at step 220, a basic injection amount Qb corresponding to the current operating state is calculated based on the engine speed NE and the accelerator opening ACCP. In step 230, the corrected injection amount Qc is determined by correcting the basic injection amount Qb determined this time based on the current cooling water temperature THW, the supercharging pressure PiM, and the like.
That is, the corrected injection amount Qc is obtained in a cold state or in accordance with the operation state of the turbocharger 51.

In step 240, the engine use time Td is calculated. This engine usage time Td is
It shows the accumulated time used after the diesel engine system of the present embodiment was shipped as a product. The engine use time Td is measured by a timekeeping function of the CPU 81. The time is measured during the operation of the ECU 71, and the backup RAM 84 is used as storage means .
Are stored cumulatively.

Then, in step 250, it is determined whether or not the engine use time Td measured as described above is equal to or longer than a predetermined reference time T1. The reference time T1 is an accumulated time required for completing the running-in operation of the diesel engine 3. Therefore, in step 250, it is determined whether or not the break-in operation of the diesel engine 3 has been completed, that is, whether or not the change in the friction loss relating to the diesel engine 3 has been eliminated.

If it is determined in step 250 that the engine use time Td is equal to or longer than the reference time T1, that is, if the break-in operation of the diesel engine 3 has been completed, the process proceeds to step 260, where the latest ISC injection amount Qisc is set. Read the value of. Subsequently, in step 270, based on the ISC injection amount Qisc, the change amount I
The SC injection amount change amount ΔQisc is calculated. In this embodiment, the difference between the latest ISC injection amount Qisc and the previous ISC injection amount Qisc obtained one time before that is used to calculate IS
The C injection amount change amount ΔQisc is obtained.

Further, at step 280, an injection amount correction amount ΔQ to be used for correcting the fuel injection amount is calculated based on the ISC injection amount change amount ΔQisc obtained this time. This calculation is performed with reference to a map in which the relationship between the ISC injection amount change amount ΔQisc and the injection amount correction amount ΔQ is determined as shown in FIG. This map is
The injection amount correction amount ΔQ is set to increase in proportion to the increase in the SC injection amount change amount ΔQisc.

Then, in step 290, it is determined whether or not the injection amount correction amount ΔQ obtained this time is equal to or greater than a predetermined reference value β. That is, the injection amount correction amount Δ
It is diagnosed whether or not Q is larger than necessary and the deterioration over time of the fuel injection device including the fuel injection pump 1 and the fuel injection nozzle 4 is larger than necessary. Here, if the injection amount correction amount ΔQ is not equal to or larger than the reference value β, it is determined that the deterioration of the fuel injection device with time after completion of the running-in operation of the diesel engine 3 is not large, and the process proceeds to step 310.
Move to. If the injection amount correction amount ΔQ is equal to or larger than the reference value β, it is determined that the deterioration of the fuel injection device with time after the completion of the running-in operation of the diesel engine 3 is unnecessarily large, and the process proceeds to step 300. Then, in step 300, after turning on the warning lamp 66 to notify the driver of the abnormality of the fuel injection device over time,
Move to step 310.

In step 310 after the transition from step 290 or step 300, the final target injection amount Q is calculated based on the corrected injection amount Qc and the injection amount correction amount ΔQ obtained this time. That is, the corrected injection amount Qc
Is corrected by the injection amount correction amount ΔQ to obtain the target injection amount Q.

Then, in step 320, 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 fuel injection amount injected from the fuel injection nozzle 4 is controlled. On the other hand, if the engine use time Td is not equal to or longer than the reference time T1 in step 250, that is, if the break-in operation of the diesel engine 3 has not been completed, the diagnosis or the like regarding the temporal deterioration of the fuel injection device as described above is prohibited. As a result, the process proceeds to step 330. And step 33
At 0, the corrected injection amount Qc obtained in step 230 is set as the target injection amount Q as it is. continue,
The process proceeds to step 320, where fuel injection is performed based on the target injection amount Q, and then the process is temporarily terminated.

As described above, according to the fuel injection device deterioration diagnosis apparatus of this embodiment, when the diesel engine 3 is idling, the idling engine speed NE is set so that the actual engine speed NE becomes the required target engine speed. Control is executed. When it is determined that the break-in operation of the diesel engine 3 has been completed, the change in the ISC injection amount Qisc obtained by the idle speed control, that is, the ISC
Based on the injection amount correction amount ΔQ obtained according to the injection amount change amount ΔQisc, the fuel injection amount other than at the time of idling is corrected. Further, the deterioration with time of the fuel injection device including the fuel injection pump 1 and the fuel injection nozzle 4 is diagnosed based on the magnitude of the injection amount correction amount ΔQ. That is, assuming that the deterioration over time of the fuel injection device is reflected on the ISC injection amount Qisc obtained by the idle speed control, the ISC injection amount change Δ
The fuel injection amount is corrected based on the injection amount correction amount ΔQ obtained according to the change in Qisc, and the deterioration of the fuel injection device with time is diagnosed. When the diagnosis result of the deterioration with time is abnormal, the warning lamp 66 is turned on.

Therefore, since the fuel injection amount is corrected in accordance with the deterioration over time of the fuel injection device, the internal cam mechanism is worn by the fuel injection pump 1 or the valve opening pressure of the fuel injection nozzle 4 is set. Even if it drops below the pressure,
The fuel injection amount is corrected in response to the deterioration over time.
As a result, it is possible to prevent the fuel injection amount from the fuel injection nozzle 4 from increasing and the fuel injection timing from shifting to the advance side. That is, good fuel injection amount control can be executed in response to the aging deterioration of the fuel injection device with high accuracy. Further, when the deterioration with time is abnormal, the driver can be immediately notified of this by turning on the warning lamp 66.

Further, in the deterioration diagnosis apparatus of this embodiment, the above-described diagnosis of deterioration with time is prohibited only until the break-in operation of the diesel engine 3 is completed.
The correction of the fuel injection amount by the injection amount correction amount ΔQ is prohibited. That is, since the fuel injection device hardly deteriorates with time before the break-in operation is completed, diagnosis of the deterioration with time during this period is prohibited.

Therefore, even if the ISC injection amount Qisc changes due to a change in the friction loss of the diesel engine 3 before the break-in operation of the diesel engine 3 is completed, it is erroneously diagnosed that the temporal deterioration of the fuel injection device is abnormal. It will not be done. In other words, the abnormality is not erroneously diagnosed while the fuel injector is not deteriorated with time.
Then, the warning lamp 66 is not erroneously turned on or the fuel injection amount is not erroneously corrected. as a result,
It is possible to more accurately diagnose the deterioration with time of the fuel injection device, to improve the reliability of the operation of the warning lamp 66, and to improve the reliability of the fuel injection amount correction performed in response to the deterioration with time. it can. Moreover, in this embodiment,
Since a special sensor is not used for judging the completion of the running-in operation of the diesel engine 3, the above-described aging diagnosis can be performed with a simple configuration.

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 ISC injection amount change amount ΔQisc is obtained from the difference between the latest ISC injection amount Qisc and the previous ISC injection amount Qisc, and the ISC injection amount change amount ΔQi is obtained.
Based on the sc, the injection amount correction amount ΔQ used for diagnosis of deterioration with time and correction of the fuel injection amount was obtained. On the other hand, an experimentally obtained actual measurement value of the actual injection amount which becomes constant after the completion of the running-in operation and the latest ISC injection amount Qis
The difference from c may be obtained as the injection amount correction amount ΔQ.

(2) In the above embodiment, the ISC injection amount change amount Δ
The injection amount correction amount ΔQ obtained according to Qisc is set to a reference value α.
Was compared with the ISC injection amount change amount ΔQis
You may make it judge the abnormality of deterioration with time by comparing c itself with a reference value.

(3) In the above embodiment, the fuel injection amount is corrected based on the injection amount correction amount ΔQ obtained in accordance with the ISC injection amount change amount ΔQisc, but the fuel injection amount is corrected in accordance with the ISC injection amount change amount ΔQisc. The fuel injection timing may be corrected based on the injection timing correction amount obtained.

(4) In the above embodiment, the warning lamp 66 is turned on when the fuel injection device is diagnosed as abnormal, but the occurrence of the abnormality is stored in the backup RAM 84 as diagnosis data together with the abnormality. The data may be readable during a periodic inspection.

(5) In the above embodiment, the engine use time Td, which is the cumulative use time of the diesel engine 3, is measured, and the diesel engine 3
The completion of the break-in operation was determined. In contrast,
The cumulative running distance of a vehicle equipped with a diesel engine may be measured, and the completion of the break-in operation may be determined based on the measurement result. Also, the engine usage time Td
When the ISC injection amount Qisc that changes with the predetermined value reaches a certain reference value, it may be determined that the break-in operation is completed. Alternatively, as a substitute value of the engine usage time Td,
It is also possible to use an integrated rotation speed that is a cumulative value of the engine rotation speed NE or an integrated injection amount that is a cumulative value of the fuel injection amount in the diesel engine 3.

(6) In the above embodiment, the diesel engine 3 is embodied as an internal combustion engine. However, any internal combustion engine having a fuel injection device including 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.

(7) In the above embodiment, the electromagnetic spill valve 23
Although the fuel injection pump 1 controls the fuel injection amount by opening the valve, the fuel injection pump may control the fuel injection amount by moving the spill ring along the plunger. it can.

[0076]

As described above in detail, according to the present invention, when the internal combustion engine is idling, the control value relating to the fuel injection amount is determined so that the actual idle speed becomes the required target speed. The drive of the fuel injection pump is feedback-controlled based on the control value. Further, based on a change in the control value determined by the feedback control, the aging of the fuel injection device is diagnosed, and the diagnosis of the aging is prohibited only until the running-in operation of the internal combustion engine is completed. I have to.

Therefore, even if the control value of the feedback control is changed due to the change in the friction loss of the internal combustion engine until the break-in operation of the internal combustion engine is completed, the fuel injection device is not deteriorated with time and the fuel injection is not affected. There is no possibility that the aging of the device is erroneously diagnosed as abnormal. As a result, it is possible to accurately diagnose the deterioration with time of the fuel injection device, and to achieve an excellent effect that it can be realized with a simple configuration without providing a special sensor or the like.

[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 block diagram illustrating a configuration of an ECU in one embodiment.

FIG. 5 is a flowchart showing a process of an “idle injection amount control routine” executed by an ECU in one embodiment.

FIG. 6 is a flowchart showing in detail a part of processing contents of an “idle injection amount control routine” in one embodiment.

FIG. 7 is a map showing a relationship between a rotational speed deviation and a corrected injection amount in one embodiment.

FIG. 8 is a flowchart showing the processing content of a “non-idle injection amount control routine” executed by the ECU in one embodiment.

FIG. 9 is a map showing a relationship between an ISC injection amount change amount and an injection amount correction amount in one embodiment.

FIG. 10 is a graph showing a relationship between an actual injection amount during idling and an ISC control value with respect to an engine operating time in the description of the related art.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Fuel injection pump, 3 ... Diesel engine as an internal combustion engine, 4 ... Fuel injection nozzle, 35 ... Rotation speed sensor as rotation speed detection means, 71 ... Idle rotation speed feedback control means, aging deterioration diagnosis means and diagnosis prohibition means E that constitutes
CU.

Continuation of the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) F02D 41/22 325 F02D 41/22 380 F02D 41/16 F02D 41/40

Claims (2)

(57) [Claims] 1. A fuel injection nozzle which is opened by obtaining a fuel pressure equal to or higher than a predetermined level and injects fuel into an internal combustion engine, and a fuel injection pump which is driven and controlled to pump fuel to the fuel injection nozzle. A fuel injection device comprising: a rotation speed detection means for detecting a rotation speed of the internal combustion engine; and an idle rotation speed detected by the rotation speed detection device when the internal combustion engine is idling. A control value related to the fuel injection amount is determined so as to be a number, and an idle speed feedback control means for feedback-controlling the driving of the fuel injection pump based on the control value, and the idle speed feedback control means based on the change of the determined by the control value, and the time degradation diagnosis means for diagnosing the deterioration with time of the fuel injection device, storage means for storing a cumulative usage amount of the internal combustion engine The following reference values for determining the cumulative usage amount stored in the storage means is complete break operation of the internal combustion engine
Deterioration diagnosis device for a fuel injection system, characterized in that the to and a cross-sectional inhibiting means diagnosis you prohibit the diagnosis of deterioration over time due to the aging deterioration diagnosis means when. 2. The internal combustion engine according to claim 2, wherein
Cumulative use time, cumulative running of vehicles equipped with the internal combustion engine
Varies with distance or cumulative time of use of the internal combustion engine.
2. The fuel injection device according to claim 1, wherein the fuel injection device comprises:
Equipment deterioration diagnosis device.