JPH09177587A - Abnormality judging device for fuel injection control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect an abnormality with a high precision for injection control devices for all cylinders even when the correction quantity of injection quantity is varied for every cylinder. SOLUTION: A fuel injection control device and an abnormality judging device thereof has an injection nozzle 4, various sensors 35, 73, 74, a central processing unit (CPU) and a backup RAM. The CPU calculates a basic injection quantity according to engine operating state, determines the rotation fluctuation for every cylinder (p) and the average value of rotation fluctuation of all cylinders (p) from the engine rotating speed, corrects the basic injection quantity so as to minimize these deviations, and injects this quantity of fuel from each injection nozzle 4. The CPU reads the correction quantity for every cylinder (p) in the initial stage of use of each injection nozzle 4 and stores it in the backup RAM as initial data. The CPU determines the deviation with the initial data in the cylinder (p) corresponding to the correction quantity, and judges that the injection system constituting part corresponding to this cylinder (p) is abnormal when the deviation is larger than a predetermined abnormality judgment value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection control device for injecting an amount of fuel corresponding to the operating state of a diesel engine from a plurality of injection nozzles into corresponding cylinders. The present invention relates to an abnormality determination device that determines the abnormality.

[0002]

2. Description of the Related Art Conventionally, in a fuel injection control device for a diesel engine, various abnormality determining devices have been proposed for determining an abnormality in an injection system component such as an injection nozzle or a fuel injection pump. For example, Japanese Patent Laid-Open No. 2-5736 discloses a technique for determining an abnormality in a fuel injection control device of a type that corrects a fuel injection amount for each cylinder.

This abnormality determination device is made by paying attention to the fact that the fuel injection control device tries to reduce the variation in the injection amount among the cylinders due to the dimensional variation of the components of the injection system and the aging. . That is, if the flow rate characteristics are different for each injection nozzle due to the various causes described above, the fuel injection amount is different for each cylinder, and the rotation fluctuations are not equal for each cylinder, causing unnecessary vibration. Further, even if the injection amounts of the injection nozzles are uniform, if the components of the fuel injection pump vary, the injection amount varies from cylinder to cylinder, causing unnecessary vibration. Therefore, in the fuel injection control device, the rotational fluctuation amount for each cylinder and the average value of the rotational fluctuation amounts for all cylinders are obtained from the rotational speed of the diesel engine, and the fuel injection amount for each cylinder is set so that the difference between the two is small. Cylinder correction amount FCCB (fuel control for
Cylinder balance) is used to increase or decrease. That is, the variation in the injection amount for each cylinder due to the components of the injection system is absorbed by increasing or decreasing the fuel supply amount to the injection nozzle.

Therefore, the flow rate characteristic of the injection nozzle can be estimated from the cylinder-by-cylinder correction amount FCCB, and the abnormality can be detected from the estimation result. From such a point of view, the abnormality determination device determines that the injection system component is abnormal when the correction amount FCCB for each cylinder is larger than a predetermined common abnormality determination value.

[0005]

However, the above-mentioned cylinder-by-cylinder correction amount FCCB differs for each cylinder. Therefore, when setting the abnormality determination value, it is necessary to allow a margin for the determination value so as not to make an erroneous determination as abnormality even in the cylinder in which the correction amount FCCB for each cylinder is the maximum when the components of the injection system are normal. That is, the abnormality determination value is used as the cylinder-by-cylinder correction amount FCCB for the cylinder.
Must be greater than. This way,
On the other hand, in a cylinder with a small correction amount FCCB for each cylinder, the difference between the abnormality determination value and the correction amount FCCB for each cylinder becomes large, and even if a large amount of fuel is injected due to an abnormality in the components of the injection system, there is an abnormality. It may not be judged. As described above, the conventional technique has a limit in improving the accuracy of detecting an abnormality, and is difficult to apply to a device requiring high detection accuracy in order to prevent deterioration of emission.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to perform abnormality detection with high accuracy with respect to the injection control device of all cylinders even if the correction amount of the injection amount differs for each cylinder. That is.

[0007]

In order to achieve the above object, the present invention provides a plurality of injection nozzles M3 provided for each cylinder M2 of a multi-cylinder diesel engine M1 as shown in FIG.
An operating state detecting means M4 for detecting an operating state of the diesel engine M1, a basic injection amount calculating means M5 for calculating a basic injection amount according to the engine operating state by the operating state detecting means M4, and each cylinder M2. Speed detection means M6 for detecting the engine speed that changes due to combustion of fuel in the engine
And an injection amount correction unit M7 that corrects the basic injection amount by the basic injection amount calculation unit M5 so that the deviation or ratio of the rotation fluctuation amount for each cylinder M2 based on the engine rotation speed by the rotation speed detection unit M6 becomes small. And the amount of fuel corrected by the injection amount correction means M7 is supplied to each injection nozzle M3.
Used in a fuel injection control device adapted to perform injection from the injection nozzle M3, and in the initial stage of use of each of the injection nozzles M3, a correction amount for each cylinder M2 by the injection amount correction device M7 is taken in and stored as initial data. The deviation or ratio of the initial data fetching means M9 to be stored in M8, the correction amount by the injection amount correcting means M7, and the initial data in the corresponding cylinder M2 stored in the storage means M8 is calculated, and the deviation or ratio is calculated. Is larger than a predetermined abnormality determination value, an abnormality determination means M10 for determining that the injection control device of the cylinder M2 is abnormal is provided.

In the above invention, the operating state detecting means M
4 detects the operating state of the diesel engine M1, and the rotation speed detection means M6 detects the engine rotation speed that changes due to the combustion of the fuel injected from the plurality of injection nozzles M3. The basic injection amount calculating means M5 calculates the basic injection amount according to the operating state, and the injection amount correcting means M7 reduces the deviation or ratio of the rotation fluctuation amount for each cylinder M2 based on the engine rotation speed. Correct the basic injection amount. Then, the amount of fuel after being corrected by the injection amount correction means M7 is equal to each injection nozzle M.
It is jetted from 3.

In the fuel injection control device in which the injection amount is corrected for each cylinder M2 as described above, the abnormality detection of the injection control device for each cylinder M2 is performed as follows. The initial data fetching means M9 fetches the correction amount for each cylinder M2 by the injection amount correcting means M7 at the initial stage of use of each injection nozzle M3, that is, when the injection system components such as the injection nozzle M3 do not change with time. This is stored in the storage means M8 as initial data. These initial data are values when the components of the injection system normally operate and a target amount of fuel or an amount of fuel close to the target amount is injected from each injection nozzle M3. At this time, if the injection flow rate varies among the injection nozzles M3 due to variations in the sizes of the components, or if the inter-cylinder injection amount changes due to variations in the pump or the like, the correction amount differs between the cylinders M2.

The abnormality determining means M10 determines the deviation or ratio between the correction amount at that time and the corresponding initial data in the cylinder M2. This deviation or ratio corresponds to the change in the injection flow rate from each injection nozzle M3. That is, as the difference between the injection flow rate and the flow rate at the initial stage of use of the injection nozzle M3 increases due to changes in the injection system components and the like, the cylinder M
The deviation of the correction amount for each 2 also becomes large. If the deviation or the ratio is larger than a predetermined abnormality determination value, the abnormality determination means M10 determines that the injection control device of the cylinder M2 is abnormal.

As described above, the initial data of the correction amount for the abnormality determination is fetched for each cylinder M2, and these initial data are those at the initial stage of use (normal operation) of each injection nozzle M3. Then, the normality / abnormality of the injection control device including the injection nozzle M3 is determined based on the deviation amount of the actual correction amount with respect to the initial data serving as the reference. Therefore, it is erroneously determined to be abnormal during normal operation of the injection system component corresponding to the cylinder M2 having the maximum correction amount, or erroneously determined to be normal when the injection system component corresponding to the cylinder M2 having the minimum correction amount is abnormal. There is no judgment.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIGS. Figure 2 shows the vehicle
Diesel engine (diesel engine) 2 as shown in
Also, the fuel injection pump 1 is mounted. The diesel engine 2 has a large number of cylinders p (for example, in the case of four cylinders, p =
1, 2, 3, 4). The fuel injection pump 1 is for supplying fuel to the injection nozzle 4 provided for each cylinder p of the diesel engine 2. A drive shaft 5 is rotatably supported by the fuel injection pump 1, and a drive pulley 3 is attached to the tip of the shaft 5 (left end in the figure). A belt or the like is mounted on the drive pulley 3 and the crankshaft 40 of the diesel engine 2, and the rotation of the crankshaft 40 is transmitted to the drive shaft 5 by the drive pulley 3, the belt, and the like.

In the fuel injection pump 1, a fuel feed pump (developed 90 degrees in the figure) 6 which is a vane type pump is provided on the drive shaft 5. A disk-shaped pulsar 7 is attached to the base end (right end in the figure) of the drive shaft 5. The same number of teeth as the number of cylinders of the diesel engine 2 are formed on the outer peripheral surface of the pulsar 7 at equal angular intervals, and a predetermined number of protrusions are formed at equal angular intervals between adjacent teeth. The base end of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown).

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

A plunger 12 for pressurizing fuel is attached to the cam plate 8, and these two members 8 and 12 interlock with the rotation of the drive shaft 5 and rotate integrally. That is, the rotational force of the drive shaft 5 is transmitted to the cam plate 8 via the coupling. By this transmission, the cam plate 8 is engaged with the cam roller 10 while rotating, and reciprocates in the left-right direction in the figure by the same number of times as the number of cylinders. With this reciprocating motion, the plunger 12 rotates and reciprocates in the same direction. That is, the plunger 12 moves forward (lifts) while the cam face 8a of the cam plate 8 rides on the cam roller 10, and vice versa.
In the process of a riding on the cam roller 10, the plunger 12
Comes back.

The plunger 12 is fitted and inserted into the cylinder 14 of the pump housing 13, and a high pressure chamber 15 is formed between the tip end surface of the plunger 12 and the inner bottom surface of the cylinder 14. A suction groove 16 and a distribution port 17 are formed on the outer periphery of the tip of the plunger 12 in the same number as the number of cylinders of the diesel engine 2. A distribution passage 18 and a suction port 19 are formed in the pump housing 13 corresponding to the suction groove 16 and the distribution port 17.

When the drive shaft 5 rotates and the fuel feed pump 6 operates, the fuel in the fuel tank (not shown) is supplied to the fuel chamber 21 through the fuel supply port 20. Further, during the intake stroke in which the plunger 12 is moved back and the high pressure chamber 15 is depressurized, one of the intake grooves 16 communicates with the intake port 19 so that the fuel chamber 21
The fuel inside is introduced into the high-pressure chamber 15. On the other hand, during the compression stroke in which the plunger 12 moves forward and the high pressure chamber 15 is pressurized, fuel is pressure-fed from the distribution passage 18 to each injection nozzle 4.

The pump housing 13 is provided with a spill passage 22 for fuel spill that connects the high-pressure chamber 15 and the fuel chamber 21. An electromagnetic spill valve 23 is provided in the spill passage 22. Electromagnetic spill valve 2
3 is a normally open valve having a coil 24, and the coil 2
When 4 is not energized (OFF), the valve body 25 is opened and the fuel in the high pressure chamber 15 is spilled into the fuel chamber 21. Also,
When the coil 24 is energized (turned on), the valve body 25 is closed and the spill of fuel from the high pressure chamber 15 to the fuel chamber 21 is stopped.

Therefore, by changing the energization time of the electromagnetic spill valve 23, the valve 23 is controlled to be closed and opened.
The spill of fuel from the high pressure chamber 15 to the fuel chamber 21 is adjusted. Then, by opening the electromagnetic spill valve 23 during the compression stroke of the plunger 12, the fuel in the high pressure chamber 15 is depressurized and the fuel injection from the injection nozzle 4 is stopped. That is, even if the plunger 12 moves forward, the fuel pressure in the high-pressure chamber 15 does not rise and the fuel is not injected from the injection nozzle 4 while the electromagnetic spill valve 23 is open. By controlling the closing and opening timings of the electromagnetic spill valve 23 during the forward movement of the plunger 12, the injection end timing of the fuel from the injection nozzle 4 is changed and the fuel injection amount is adjusted.

Below the pump housing 13, a timer device (developed by 90 degrees in the figure) 26 for changing the fuel injection timing is provided. This timer device 2
6 is a cam face 8a by changing the position of the roller ring 9 with respect to the rotation direction of the drive shaft 5.
Changes the timing of engagement with the cam roller 10, that is, the reciprocating drive timing of the cam plate 8 and the plunger 12.

The timer device 26 is driven by control hydraulic pressure, and includes a timer housing 27 and the same housing 2.
7, the timer piston 28 is fitted in the timer housing 27, and the timer piston 28 is attached to the pressure chamber 30 on the other side (right side in the figure) in the low pressure chamber 29 on the one side (left side in the figure) in the timer housing 27. It is composed of a urging timer spring 31 and the like. The timer piston 28 is connected to the roller ring 9 via a slide pin 32.

Fuel pressurized by the fuel feed pump 6 is introduced into the pressure chamber 30. The position of the timer piston 28 is determined by the equilibrium relationship between the fuel pressure and the urging force of the timer spring 31. Along with this, the position of the roller ring 9 is determined, and the reciprocating timing of the plunger 12 is determined via the cam plate 8.

The timer device 26 is provided with a timing control valve (TCV) 33 in order to adjust the fuel pressure acting as the control oil pressure of the timer device 26. That is, the pressurizing chamber 30 and the low pressure chamber 29 of the timer housing 27 are communicated with each other by the communication passage 34, and the TCV 33 is interposed in the communication passage 34. TCV
Reference numeral 33 is a solenoid valve which is opened / closed by a duty-controlled energization signal, and the fuel pressure in the pressurizing chamber 30 is adjusted by adjusting the opening of the TCV 33. Then, by the adjustment, the reciprocating timing of the plunger 12 is changed, and the fuel injection timing of each injection nozzle 4 is adjusted.

On the upper part of the roller ring 9, a rotation speed sensor 35 constituting a part of the operating condition detecting means is attached so as to face the outer peripheral surface of the pulsar 7. The rotation speed sensor 35 is composed of an electromagnetic pickup coil, detects the passage of the protrusions formed on the outer peripheral surface of the pulsar 7 when they cross, and outputs a timing signal (engine rotation pulse). That is, the rotation speed sensor 35 determines that the predetermined crank angle of the diesel engine 2 (for example, 11.25 ° CA, CA
Is an abbreviation for crank angle) and outputs a pulse signal every time. Since this rotation speed sensor 35 is integrated with the roller ring 9, it outputs a reference signal to the plunger lift at a fixed timing regardless of the control operation of the timer device 26.

Next, the diesel engine 2 will be described. In the engine 2, the cylinder p, the piston 42, and the cylinder head 43 form a main combustion chamber 44 corresponding to each cylinder p. In addition, each main combustion chamber 4
An auxiliary combustion chamber 45 communicating with No. 4 is provided corresponding to each cylinder p. Then, the fuel is injected from each injection nozzle 4 into each auxiliary combustion chamber 45. In each sub-combustion chamber 45, there is a well-known glow plug 4 as a starting assist device.
6 are attached respectively.

A turbocharger 48 is mounted on the diesel engine 2. The turbocharger 48 includes a turbine 51 arranged in the middle of the exhaust pipe 50 and an intake pipe 4
7 is provided with a compressor 49 and a shaft connecting the turbine 51 and the compressor 49. The exhaust pipe 50 has a turbocharger 48.
A waste gate valve 52 for adjusting the supercharging pressure by

The exhaust pipe 50 and the intake pipe 47 are connected to each other by a return pipe 54 so that a part of the exhaust gas in the exhaust pipe 50 can be returned to the intake pipe 47 through the return pipe 54. There is. An EGR valve 55 for adjusting the exhaust gas recirculation amount (EGR amount) is provided in the middle of the recirculation pipe 54. The negative pressure introduced into the diaphragm chamber of the EGR valve 55 is the vacuum switching valve (VS
V) 56. The VSV 56 is controlled by an on / off duty signal. More specifically,
When the duty ratio increases, the current value to the VSV 56 increases and the negative pressure in the diaphragm chamber of the EGR valve 55 increases. Accordingly, the flow passage area of the reflux pipe 54 increases, and
The amount of R increases.

In the middle of the intake pipe 47, the accelerator pedal 5
Throttle valve 58 that opens and closes in conjunction with the depression amount of 7
Is provided. A bypass passage 59 is provided in the intake pipe 47 in parallel with the throttle valve 58, and a bypass throttle valve 60 is supported in the middle thereof. The bypass throttle valve 60 is controlled to be opened / closed by an actuator 63 having a two-stage diaphragm chamber driven by two VSVs 61 and 62. The bypass throttle valve 60 is controlled to open and close according to various operating states. For example, the bypass throttle valve 60
When the diesel engine 2 is idling, the diesel engine 2 is in a half-open state to reduce noise and vibrations, is in a fully open state in a normal operation, and is in a fully closed state for a smooth stop when the operation is stopped.

An instrument panel (not shown) of the vehicle incorporates a warning lamp 65 for notifying the driver of the abnormality of the injection nozzle 4. The warning lamp 65 is turned on or off as a result of abnormality detection described later.

The electromagnetic spill valve 2 provided in the fuel injection pump 1 and the diesel engine 2 as described above
3, TCV33, glow plug 46, each VSV56, 6
1, 62 and the warning lamp 65 are respectively connected to an electronic control unit (hereinafter simply referred to as “ECU”) 71,
U71 controls the drive timing of them.

In order to detect the operating state of the diesel engine 2, the following various sensors are provided in addition to the rotational speed sensor 35 described above. An intake air temperature sensor 72 for detecting the intake air temperature THA is attached near the air cleaner 64 at the inlet of the intake pipe 47.

In the intake pipe 47, an accelerator opening sensor 73 for detecting the accelerator opening ACCP corresponding to the load of the diesel engine 2 from the opening / closing position of the throttle valve 58.
Is provided. In the vicinity of the intake port 53, the intake pressure PiM after being supercharged by the turbocharger 48.
An intake pressure sensor 74 for detecting The accelerator opening sensor 73 and the intake pressure sensor 74 together with the above-described rotation speed sensor 35 constitute a part of the operating state detecting means.

Further, in the diesel engine 2, a water temperature sensor 75 for detecting the cooling water temperature THW and a crank for detecting the rotation reference position of the crankshaft 40, for example, the rotation position of the crankshaft 40 with respect to the top dead center of the specific cylinder p. An angle sensor 76 is provided. The transmission (not shown) is provided with a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SP by turning on / off a reed switch 77b by a magnet 77a rotated by the rotation of the gear.

Each of the sensors 35, 72 to 77 described above is an EC.
Each is connected to U71. The ECU 71 uses the electromagnetic spill valve 23, the TCV 33, the glow plug 46 and the VSV 56, based on the detection signals of the sensors 35, 72 to 77.
61 and 62 are controlled respectively.

Next, the structure of the above-mentioned ECU 71 will be described with reference to the block diagram of FIG. The ECU 71 includes a central processing unit (CPU) 81, a predetermined control program,
Read-only memory (ROM) that stores maps in advance
A random access memory (RAM) 83 for temporarily storing a calculation result of the CPU 81 and the like, and a backup RAM 84 for storing previously stored data. These parts 81 to 84, the input port 85, and the output port 86
Are connected by a bus 87.

The intake temperature sensor 72, the accelerator opening sensor 73, the intake pressure sensor 74 and the water temperature sensor 75 described above are
Input port 85 via buffers 88, 89, 90, 91, multiplexer 92 and A / D converter 93, respectively.
It is connected to the. The rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 are connected to the input port 85 via the waveform shaping circuit 95. The CPU 81 reads the detection signals of the sensors 35, 72 to 77 via the input port 85.

The electromagnetic spill valve 23, the TCV 33, the glow plug 46, the VSVs 56, 61, 62 and the warning lamp 65 are provided with drive circuits 96, 97, 98, 99, respectively.
It is connected to the output port 86 via 100, 101 and 102. The CPU 81, based on the input value read through the input port 85, the electromagnetic spill valve 23, TCV
33, the glow plug 46, the VSVs 56, 61, 62 and the warning lamp 65 are preferably controlled.

Next, the operation and effect of this embodiment configured as described above will be described. The flowchart of FIG. 4 shows a routine for calculating the cylinder-by-cylinder correction amount FCCB (p) among the processes executed by the CPU 81, and the flowchart of FIG. 6 shows a routine for controlling the fuel injection amount. . The flowchart of FIG. 7 shows a routine for storing the initial correction amount BFCCB (p) which is the initial data of the cylinder-by-cylinder correction amount FCCB (p).
The flowchart of FIG. 8 shows a routine for detecting an abnormality in the injection system components such as the injection nozzle 4 and the fuel injection pump 1.

In the cylinder-by-cylinder correction amount calculation routine of FIG.
In step 101, the PU 81 first measures the time ΔT required for the drive shaft 5 (crankshaft 40) to rotate by a predetermined angle (for example, 45 ° CA) based on the engine rotation pulse output from the rotation speed sensor 35. To do. From this time ΔT, the rotational speed (instantaneous rotational speed) NEi (i = 1 to 4) of the period during which the drive shaft 5 rotates 45 ° CA is calculated for each cylinder p (p = 1 to 4).

Next, at step 102, the rotational fluctuation DNEp for each cylinder p is calculated based on the instantaneous rotational speed NEi. For example, the deviation between the maximum value and the minimum value of the instantaneous rotation speed NEi is obtained for a predetermined cylinder p, and this deviation is set as the rotation fluctuation DNEp. This process is performed for all cylinders p. Then, four rotation fluctuations DNE1, DNE2,
DNE3 and DNE4 are obtained.

Then, in step 103, all cylinders
The average value WNDLT of the rotation fluctuation DNEp of p is calculated.
For example, the rotation fluctuations DNE1, DNE2, DN of all cylinders p
The average value WNDLT is obtained by adding E3 and DNE4 and dividing this by "4".

In step 104, the average value WN
The deviation DDNEp between the DLT and the rotational fluctuation DNEp is determined by the cylinder p
For each cylinder, the correction amount FCCB (p) for each cylinder corresponding to each deviation DDNEp is obtained in step 105 with reference to the map shown in FIG.

In this map, the deviation DDNEp is "0".
When it belongs to the range from "a" to "b" including "," the correction amount FCCB for each cylinder is set to "0". Deviation DD
In the region where NEp is smaller than "a" and the region where it is larger than "b", the correction amount FCCB for each cylinder is set to decrease as the deviation DDNEp increases. In other words, the cylinder-by-cylinder correction amount FCCB is the rotational fluctuation DN.
It is "0" when Ep is a value close to the average value WNDLT, and becomes larger as the rotational fluctuation DNEp becomes smaller than the average value WNDLT (FCCB> 0), and the rotational fluctuation DNE.
It becomes smaller as p becomes larger than the average value WNDLT (FCCB <0). In the map of FIG. 5, the average value WNDL
In the cylinder p whose rotation speed is higher than T, the correction amount FCCB for each cylinder is reduced to suppress the rotation fluctuation. And
After the correction amount FCCB (p) for each cylinder is calculated in step 105, this routine ends.

As described above, according to the correction amount calculation routine for each cylinder, the rotation fluctuation DN for each cylinder p of the diesel engine 2 is changed.
Ep is calculated, and the deviation D between that value and the average value WNDLT
DNEp is required. Then, the cylinder-by-cylinder correction amount FCCB (p) for correcting the fuel injection amount for each cylinder p in the direction of decreasing the deviation DDNEp is obtained.

Next, the fuel injection control routine of FIG. 6 will be described. In step 201, the CPU 81 reads the engine speed NE, the accelerator opening ACCP by the accelerator opening sensor 73, the intake pressure PiM by the intake pressure sensor 74, the cylinder correction amount FCCB (p), and the like. The engine rotational speed NE is, for example, 180 ° C. in step 101 in the above-described correction amount calculation routine for each cylinder.
The average value of the instantaneous rotation speed NEi between A can be used. In this case, (NE1 + NE2 + NE3 + NE4) /
4 is used as the engine rotation speed NE.

Then, in step 202, the ROM
With reference to the map stored in 82, the basic injection amount QBASE corresponding to the accelerator opening ACCP, the engine speed NE, etc. is calculated. In step 203, the maximum injection amount QFULL, which is the maximum value of the injected fuel amount burned in the intake air to the diesel engine 2, is calculated based on the engine speed NE, the intake pressure PiM, and the like.

In step 204, a correction coefficient K5 (0 <K5 ≦ 1.0) according to the engine speed NE is calculated. The correction coefficient K5 is for preventing hunting when the engine speed NE is relatively high (1000 to 1500 rpm), and can be obtained by referring to a map stored in the ROM 82, for example.

Next, at step 205, the product of the cylinder-by-cylinder correction amount FCCB (p) and the correction coefficient K5 is added to the basic injection amount QBASE at step 202 to obtain the injection amount QBASE1. Then, in step 206, it is determined whether the injection amount QBASE1 is smaller than the maximum injection amount QFULL in step 203.

The above judgment condition is satisfied (QBAS
E1 <QFULL) and the injection amount Q at step 207
BASE1 is set as the final injection amount QFIN, and the same determination condition is not satisfied (QBASE1 ≧ QFULL)
Then, in step 208, the maximum injection amount QFULL is set as the final injection amount QFIN. As described above, in steps 206 to 208, the smaller one of the injection amounts QBASE1 and QFULL is selected, and this is selected as the final injection amount Q.
Set as FIN.

Then, in step 209, the injection amount command value Vs corresponding to the final injection amount QFIN is output. That is, the fuel supply amount from the fuel injection pump 1 to the injection nozzle 4 is controlled by driving and controlling the electromagnetic spill valve 23 based on the injection amount command value Vs.

The CPU 81 and the process of step 202 in the fuel injection control routine correspond to the basic injection amount calculation means. Further, the CPU 81, the processing of steps 101 to 105 in the correction amount calculation routine for each cylinder,
The process of step 205 in the fuel injection control routine corresponds to injection amount correction means.

Next, the initial correction amount storage routine of FIG. 7 will be described. This routine is repeatedly executed at predetermined time intervals from when the key switch of the vehicle is turned on until it is turned off. Further, each processing of this routine is performed based on the counter C and the flag FBFCC. The counter C is for integrating the time elapsed since the diesel engine 2 was first operated, counts the number of executions of the initial correction amount storage routine, and stores the count value IT in the backup RAM 84. This count value IT corresponds to the operating time of the diesel engine 2.

The flag FBFCC is an initial correction amount BFC which is the initial value of the cylinder-by-cylinder correction amount FCCB (p) of each cylinder p.
It is for determining whether or not CB (p) is stored in the backup RAM 84, is set to "0" at the start of operation of the diesel engine 2, and the count value IT is a predetermined determination value STo. When it becomes larger than the above, it is switched to "1".

First, in step 301, the CPU 81 performs an engine operating time integration process. More specifically, each time the initial correction amount storage routine is executed, the backup RAM
"1" is added to the count value in the previous control cycle stored in 84, and the added value is stored in the backup RAM 84 as the count value IT in the current control cycle.

In step 302, the flag FBFCC is set.
Is determined to be “1”. If this determination condition is satisfied (FBFCC = 1), it is determined that the initial correction amount BFCCB (p) of each cylinder p has already been stored in the backup RAM 84, and this routine is ended as it is. On the other hand, the above determination condition is not satisfied (FB
FCC = 0) and the initial correction amount BFCCB for each cylinder p still
It is determined that (p) is not stored, and the process proceeds to step 303.

In step 303, it is determined whether the count value IT is larger than the determination value STo. The determination value STo here is determined in consideration of the following points.
The correction amount FCCB (p) for each cylinder remains at the initial value at the start of use of the vehicle. The FCCB (p) converges to a value for correcting the injection between the cylinders by learning after a certain amount of time has elapsed from the start of use of the vehicle, that is, the correction amount routine for each cylinder of FIG. 4 is repeatedly performed. This is after the variation in rotation of each cylinder is absorbed by learning. Judgment value STo
Is set in consideration of such circumstances, and has a value corresponding to the time required for the variation in the correction amount FCCB (p) for each cylinder to become a sufficiently small value.

When the determination condition of step 303 is not satisfied (IT≤STo), the above-mentioned correction amount F for each cylinder is corrected.
The variation in CCB (p) is still large, and it is determined that the correction amount calculation routine for each cylinder needs to be further repeated to reduce this variation, and this routine is ended. On the other hand, if the determination condition of step 303 is satisfied, the correction amount calculation routine for each cylinder is performed for a sufficient time from the start of use of the vehicle, and the variation of the correction amount FCCB (p) for each cylinder at the start of use is varied. Since it is smaller, it is determined that the counter C does not need any further counting operation, and in step 304, the cylinder-by-cylinder correction amount F of each cylinder p is determined.
Read CCB (p) and use that value as the initial correction amount BFCCB
It is stored in the backup RAM 84 as (p). Then, in step 305, the flag FBFCC is set to "0".
To "1" and this routine is completed.

The CPU 81 and the processing of steps 301 to 305 in the above-described initial correction amount storage routine correspond to the initial data fetching means. Therefore, according to the storage routine, steps 301 to 301 are performed when the vehicle starts to be used.
The process of 03 is repeatedly performed, the count value IT is counted up, and the operating time of the diesel engine 2 is integrated. The flag FBFCC remains "0". When the diesel engine 2 is operated for some time from the start of use and the count value IT exceeds the determination value STo, the processes of steps 301 to 305 are sequentially performed, and the correction amount FCCB (p) for each cylinder at that time is The initial correction amount BFCCB (p) is set and the flag FB is set.
The FCC is switched from "0" to "1". From the next control cycle onward, the determination condition of step 302 is satisfied, and therefore the processes of steps 301 and 302 are repeated.

As described above, at the initial stage of use of the injection nozzles 4, the fuel injection pump 1 and the like, that is, at the stage when the components of the fuel injection system have not changed with time, the correction amount FCCB (p for each cylinder of all cylinders p is changed. ) Is taken in and stored in the backup RAM 84 as initial data. These initial data show that the injection system components are operating normally,
It is a value when a target amount of fuel or an amount close to it is injected from each injection nozzle 4.

Next, the abnormality detection routine of FIG. 8 will be described. In step 401, the CPU 81 determines the correction amount FCCB (p) for each cylinder and the initial correction amount BFCC at that time.
Read B (p) respectively. Next, at step 402, a deviation Δ between both correction amounts FCCB (p) and BFCCB (p)
FCCB (p) is obtained, and it is determined whether the absolute value is larger than a predetermined abnormality determination value ThFCCB.
The absolute value of this deviation | ΔFCCB (p) | corresponds to the change in the injection flow rate of each injection nozzle 4. That is, the absolute value | ΔFCCB (p) | increases as the difference between the injection flow rate and the flow rate at the initial stage of use of the injection nozzle 4 and the like increases due to changes over time in the components of the injection system. The determination condition in step 402 is satisfied (| ΔF
CCB (p) |> ThFCCB), it is determined that the injection system components are abnormal, and a signal for turning on the warning lamp 65 is output to notify the driver of the abnormality, and the process proceeds to step 404. On the other hand, the determination condition is not satisfied (| ΔFCCB (p) | ≦ ThFCCB)
Then, it is determined that the injection system components are operating normally, and the process proceeds to step 404.

In step 404, it is determined whether or not the abnormality determination has been made for all cylinders p. If this determination condition is not satisfied, the processes of steps 401 to 403 described above are executed. If the determination condition of step 404 is satisfied by this processing, this routine is ended.

The CPU 81 and the processes of steps 401 to 404 in the abnormality detection routine correspond to abnormality determining means. Thus, in this embodiment, the initial correction amount BFCCB (p) for abnormality determination is taken in for each cylinder p, and the initial correction amount BFCCB (p) is used in the initial stage of use of the injection system components (normal (During operation). Then, the cylinder-by-cylinder correction amount FCCB (p) is monitored, and based on the deviation amount of the actual cylinder-by-cylinder correction amount FCCB (p) from the initial correction amount BFCCB (p), whether the injection system constituent parts are normal or abnormal is determined. A decision is made. Cylinder correction amount FCC
When B (p) greatly deviates from the initial correction amount BFCCB (p), it is determined that the injection system component is abnormal. In the self-diagnosis, the initial correction amount BFCCB (p) for each cylinder p
Is used as a reference, the abnormality detection accuracy is high, and it is erroneously determined to be abnormal during normal operation of the injection system component corresponding to the cylinder p for which the cylinder-by-cylinder correction amount FCCB (p) is maximum.
There is no erroneous determination as normal when an abnormality occurs in an injection system component corresponding to the cylinder p having the smallest CCB (p).

Since the abnormality detection accuracy is improved in this manner, unlike the prior art, the correction amount FCCB (p) for each cylinder is different.
It is not necessary to allow the abnormality determination value ThFCCB to have a margin so as to prevent the abnormality determination from being erroneously made in the cylinder having the maximum value even when the injection system components are normal. Therefore, it is possible to solve the problem when the abnormality determination value ThFCCB is set to a value larger than the correction amount FCCB (p) for each cylinder in the cylinder p. That is, the correction amount FCCB for each cylinder
When a large amount of fuel is injected due to an abnormality in the injection system components in the cylinder p having a small number of (p), it may be determined to be normal in the prior art, whereas it is determined to be abnormal in the present embodiment. be able to. Therefore, the technology of the present embodiment can be preferably applied to a fuel injection control device that requires high detection accuracy in order to prevent deterioration of emission.

The present embodiment has the following features in addition to the matters described above. (A) If the correction amount FCCB (p) for each cylinder at the start of operation of the diesel engine 2 is used as the initial correction amount BFCCB (p), the correction amount BFCCB (p) becomes the correction amount FCCB (p) for each cylinder. This includes the variations that it has, and the accuracy of abnormality detection is impaired. On the other hand, in the present embodiment, after a certain amount of time has passed from the start of operation, that is, the correction amount FCCB (p) for each cylinder after the count value IT exceeds the determination value STo is set to the initial correction amount BFCCB (p). Used as. Therefore, the cylinder-by-cylinder correction amount FCCB (p) whose variation is reduced by repeatedly executing the cylinder-by-cylinder correction amount calculation routine becomes the initial correction amount BFCCB (p). This point is also advantageous in improving the accuracy of abnormality detection.

(B) The state of the injection system components is automatically diagnosed during operation of the diesel engine 2. The initial correction amount BFCCB (p) for diagnosis is also automatically set. Therefore, the driver does not have to perform a special operation for diagnosis.

(C) If the injection system components are abnormal,
The fact can be notified to the driver immediately by turning on the warning lamp 65. (D) The injection control technology is used to correct the injection amount for each cylinder in order to detect abnormalities in the injection system components. Therefore, it is not necessary to separately provide a dedicated sensor or diagnostic mechanism. Diagnosis can be done with a very simple configuration.

The present invention can be embodied in another embodiment shown below. (1) In the above embodiment, the present invention is embodied in a fuel injection control device of a type in which the fuel injection amount is controlled by operating the electromagnetic spill valve 23 of the fuel injection pump 1. However, the spill ring is mounted on the plunger. Can also be embodied in a fuel injection control device that controls the fuel injection amount by changing the position of the spill ring according to the operating state of the engine.

(2) In the above embodiment, the warning lamp 65 is turned on when it is determined that the injection system component is abnormal, but instead of this, the backup RAM 84 uses the abnormality occurrence as diagnostic data. Alternatively, the data may be read out when the vehicle is inspected or repaired.

(3) In the above embodiment, the engine operating time, which is the cumulative use period of the diesel engine 2, is measured, and the initial stage of use of the injection nozzle 4 is determined based on the measurement result. Instead of this, the cumulative traveled distance of the vehicle equipped with the diesel engine may be measured, and the initial stage of use may be determined based on the measurement result. The mileage can be calculated from the output shaft of the transmission and the rotation speed of the wheels.

Instead of the engine operating time, the integrated value of the number of revolutions of the diesel engine 2 or the integrated value of the fuel injection amount may be used. (4) The present invention can also be applied to a fuel injection control device in which FCCB (p) is calculated as the correction amount for each cylinder by a method different from the above-described embodiment. In this method, the instantaneous rotation speed NEi (i = 1 to 4) is calculated for each cylinder p (p = 1 to 4), and the deviation ((NEi-1)-((NEi-1)-() of the continuous rotation speeds NEi-1 and NEi is calculated. NE
i)) is the rotation fluctuation amount, and the correction amount FCCB (p) for each cylinder for correcting the fuel injection amount for each cylinder p in the direction of reducing this fluctuation amount is obtained. Therefore, if the rotational fluctuation amount is positive, the cylinder correction amount FCCB (p) becomes a value for correcting the fuel injection amount reduction, and if the rotational fluctuation amount is negative, the cylinder correction amount FCCB (p). Is a value for increasing and correcting the fuel injection amount.

(5) In the present invention, the instantaneous rotation speed NEi (i = 1
Based on (4) to (4), the basic injection amount QBASE can be corrected so that the ratio of the rotation fluctuation amount for each cylinder p becomes small.

(6) In the above embodiment, the initial correction amount B
When the absolute value of the deviation between FCCB (p) and the correction amount FCCB (p) for each cylinder is larger than the abnormality determination value ThFCCB, it is determined that the injection system component is abnormal.
An abnormality may be determined when the ratio of B (p) and FCCB (p) is larger than a predetermined abnormality determination value.

Although the respective embodiments of the present invention have been described above, technical ideas other than the claims which can be understood from the respective embodiments will be described below together with their effects. (A) In the abnormality determination device according to claim 1, the initial data fetching means integrates an operating time or a traveling distance from the start of operation of the diesel engine, and the integrated value is larger than a predetermined determination value. The abnormality determination device of the fuel injection control device, which takes in the correction amount for each cylinder by the injection amount correction means when With such a configuration, even if the correction amount for each cylinder varies, it is possible to capture a value having the variation as initial data, and further improve the abnormality detection accuracy.

(B) In the abnormality determination device described in (a) above, the determination value is a value corresponding to the time required for the rate of change of the correction amount by the injection amount correction means to decrease. Anomaly judgment device. With such a configuration, the effect of (a) above can be surely exhibited.

[0075]

As described above in detail, according to the present invention, the correction amount for each cylinder is taken in and stored as initial data at the initial stage of use of each injection nozzle, and the deviation between the initial data and the correction amount is stored. Alternatively, since the abnormality determination is made based on the ratio, even if the correction amount of the injection amount differs for each cylinder, the abnormality detection can be performed with high accuracy for the injection control devices of all the cylinders.

[Brief description of the drawings]

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

FIG. 2 is a schematic configuration diagram of a diesel engine and a fuel injection pump.

FIG. 3 is a block diagram showing an electrical configuration of an ECU.

FIG. 4 is a flowchart illustrating a correction amount calculation routine for each cylinder.

FIG. 5 is a characteristic diagram showing a map defining a relationship between a deviation and a correction amount for each cylinder.

FIG. 6 is a flowchart illustrating a fuel injection control routine.

FIG. 7 is a flowchart illustrating an initial correction amount storage routine.

FIG. 8 is a flowchart illustrating an abnormality detection routine.

[Explanation of symbols]

2 ... Diesel engine (diesel engine), 4 ... Injection nozzle, 35 ... Rotation speed sensor that constitutes a part of the operation state detection means and also constitutes rotation speed detection means, 7
3 ... Accelerator opening sensor forming part of operating condition detecting means, 74 ... Intake pressure sensor forming part of operating condition detecting means, 81 ... CPU, 84 ... Backup RAM as storage means, NE ... Engine rotation Speed, QBASE ...
Basic injection amount, p ... Cylinder, DNEp ... Rotational fluctuation, WNDL
T ... Average value, DDNEp ... Deviation, BFCCB (p) ... Initial correction amount as initial data, .DELTA.FCCB (p) ... Deviation, T
hFCCB (p) ... Abnormality judgment value.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification number Internal reference number FI Technical display location F02D 45/00 364 F02D 45/00 364Q (72) Inventor Shigeki Hidaka 1 Showa-cho, Kariya city, Aichi prefecture 1-chome Nihon Denso Co., Ltd.

Claims (1)

[Claims] 1. A plurality of injection nozzles provided for each cylinder of a multi-cylinder diesel engine, an operating state detecting means for detecting an operating state of the diesel engine, and a basic unit according to an engine operating state by the operating state detecting means. Basic injection amount calculation means for calculating an injection amount, rotation speed detection means for detecting an engine rotation speed that changes due to combustion of fuel in each cylinder, and rotation for each cylinder based on the engine rotation speed by the rotation speed detection means An injection amount correction unit that corrects the basic injection amount by the basic injection amount calculation unit so that the deviation or ratio of the variation amount becomes small, and the amount of fuel corrected by the injection amount correction unit is supplied from each injection nozzle. A fuel injection control device for injecting fuel, wherein correction is made for each cylinder by the injection amount correction means at an initial stage of use of each injection nozzle. Is obtained, and a deviation or a ratio between the initial data fetching means for storing it in the storage means as the initial data, the correction amount by the injection amount correcting means, and the initial data in the corresponding cylinder stored in the storage means, An abnormality determination device for a fuel injection control device, comprising an abnormality determination means for determining that the injection control device of the cylinder is abnormal when the deviation or the ratio is larger than a predetermined abnormality determination value.