JP3089135B2 - Fuel injection amount control device for internal combustion engine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel injection system for a diesel engine or the like based on an engine speed and an accelerator operation amount.
The injection amount is set and the fuel injection amount
The present invention relates to a fuel injection amount control device for an internal combustion engine in which the intake air amount is adjusted .

[0002]

2. Description of the Related Art Conventionally, a diesel engine is provided with an exhaust gas recirculation (EGR) device for recirculating a part of exhaust gas to intake air for the purpose of reducing nitrogen oxides (NOx) contained in the exhaust gas. It is known. This E
The GR device includes an EGR passage capable of communicating between an exhaust system and an intake system, and a diaphragm-type EGR valve that is opened and closed by using a negative pressure as an operation source is provided in the EGR passage. Further, a negative pressure control valve which is electrically controlled to control the supply of the negative pressure to the EGR valve is provided.
In the EGR device configured as described above, the negative pressure control valve is controlled in accordance with the operation state of the diesel engine, so that the EGR valve is opened and closed to control the amount of EGR for the diesel engine. Specifically, in a steady operation state in which the diesel engine has a low to medium load, the EGR
The negative pressure control valve is controlled so that the EGR valve is opened so as to allow the pressure. On the other hand, during transient operation when the load becomes high (eg during acceleration)
Thus, the EGR valve is controlled so as to be closed to shut off the EGR.

In this type of EGR device, since an EGR valve using a negative pressure as an operation source is used, the EGR amount can be controlled with high reliability by a relatively simple configuration. However, on the other hand, there is a problem in the open / close responsiveness of the EGR valve to the switching of the negative pressure. Therefore, when the diesel engine is accelerated from the steady operation state, a temporary delay in closing the EGR valve occurs even though the fuel injection amount is increased in accordance with the acceleration request. The amount could be temporarily excessive. Therefore, when the EGR amount becomes excessive, the real air amount to be supplied to the diesel engine,
That is, the excess air ratio becomes too small, and there is a possibility that the exhaust emission is deteriorated, for example, the emission of smoke is increased.

[0004] In addition to the above EGR device, it is conceivable to provide an intake throttle valve or a supercharger in the intake system in order to control the actual amount of air to be supplied to the diesel engine. Can be Also in these cases, due to the response delay of the intake throttle valve and the supercharger during transient operation such as acceleration,
There is a possibility that the actual air amount becomes too small and the exhaust emission deteriorates.

Therefore, a technique for addressing the above-mentioned problem has been proposed in Japanese Utility Model Laid-Open Publication No. Sho 61-6651. In this prior art, a delay until the EGR valve is fully closed or a delay until the intake throttle valve is fully opened during acceleration is detected. By correcting the fuel injection amount to the diesel engine only during that delay,
It is disclosed that deterioration of exhaust emissions during acceleration is avoided. That is, the period during which the actual amount of air to be supplied to the diesel engine during acceleration is too small is measured by detecting that the EGR valve is fully closed and the intake throttle valve is fully opened, and the fuel injection is performed only until the detection is completed. The amount is reduced.

[0006]

However, in the above-mentioned prior art, it is anticipated that the actual air amount will be too small by a predetermined amount during a delay in closing the EGR valve and a delay in opening the intake throttle valve during acceleration. Only the correction of the decrease in the fuel injection amount is performed uniquely. That is, the fuel injection amount is simply reduced uniformly based on the expected real air amount. Therefore, if there are individual differences or changes over time in the manner of opening and closing the EGR valve and the intake throttle valve, the amount of air actually taken into the diesel engine differs from the expected real air amount, and as a result, the fuel injection Correction of the amount reduction is not performed properly. Moreover, it is known that the intake system itself of a diesel engine itself has some individual differences and changes with time. Therefore, during transient operation such as acceleration, unless the necessary fuel amount is set by accurately capturing the change in the actual air amount due to the individual differences in the configuration and the change over time, an appropriate reduction correction regarding the fuel injection amount is performed. I can't do that.

In order to accurately measure an intake air amount corresponding to a substantial air amount in an internal combustion engine, it is already known to use an intake air amount detecting means such as an air flow meter. There are some solid differences and aging. Therefore, when using the intake air amount detection means, in order to accurately correct the decrease in the fuel injection amount during the transient operation, it is also an issue to obtain the intake air amount more accurately in accordance with individual differences and changes over time. I have.

The present invention has been made in view of the above-described circumstances, and is based on an engine speed and an accelerator operation amount.
And the fuel injection amount is set
It is premised on an internal combustion engine in which the intake air amount is adjusted in such a manner . And the purpose is that during the transient operation of the internal combustion engine, E
The fuel injection amount is accurately corrected by taking into account the operation delay of the means for substantially adjusting the intake amount such as the GR valve, and the individual differences and aging of the intake system and the intake amount detecting means including such means. It is an object of the present invention to provide a fuel injection amount control device for an internal combustion engine that is capable of performing the above .

[0009]

In order to achieve the above object, according to the present invention, an engine speed and an accelerator
The fuel injection amount is set based on the manipulated variable and the fuel
Internal combustion engine whose intake air amount is adjusted to match the fuel injection amount
The fuel injection amount control device for detecting the intake air amount
Intake amount detecting means for operating the internal combustion engine in a steady operation state
Is determined based on the engine operating condition.
Means for calculating the intake air amount calculated by the
To determine whether the vehicle is in the
Disconnection means and a determination that the internal combustion engine is in a steady operation state.
The detected intake air amount and the calculated constant
A learning means for learning a deviation from a constant intake amount;
Based on the learning result of the learning means.
Steady-state intake air amount correction means for correcting
When it is determined that the vehicle is in the transient operation state,
And the corrected steady-state intake air amount is compared.
The fuel for correcting the set fuel injection amount based on the result is
Fuel injection amount control for an internal combustion engine provided with fuel injection amount correction means
The device is the gist.

[0010]

[0011]

[0012]

[Action] According to the above configuration, the internal combustion engine is in a transient operation state.
In some cases, the intake air amount detected by the intake air amount detection means
Is compared with the steady-state intake air amount corresponding to the steady-state operating condition.
The fuel injection amount is corrected based on the comparison result.
Therefore, the intake air amount may be reduced due to, for example, an operation delay of the EGR valve.
Changes after the change in
When there is a difference between the air volume and the actual intake air volume.
The fuel injection amount is corrected according to the change in intake air amount.
Therefore, the fuel injection amount can be optimized.
Further, when the internal combustion engine is in a steady operation state,
The constant intake air amount and the intake air amount detected by the intake air amount detection means
Is learned. Then, based on this learning result,
Is referred to when correcting the fuel injection amount during the transient operation.
The constant intake amount is corrected. As a result, during transient operation
For example, the EGR valve or the like or the intake air amount
Differences in the intake system and intake air amount detection means, such as sensors that detect
And changes over time are reflected.

[0013]

EXAMPLES Hereinafter, will be described in detail based on an embodiment embodying the fuel injection control apparatus for an engine electronic control diesel engine of a motor vehicle in the present invention in FIGS. 1 to 6.

FIG. 1 shows a schematic configuration of a diesel engine system with a supercharger in this embodiment, and FIG. 2 shows an enlarged view of the distribution type fuel injection pump 1. 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, a fuel injection means is constituted by the fuel injection pump 1, the fuel injection nozzle 4, the fuel line 4a and the like. The fuel injection nozzle 4 is an automatic valve having a built-in needle valve, and is opened by obtaining a fuel pressure of a predetermined level or more. Therefore, the fuel pumped from the fuel injection pump 1 applies a fuel pressure of a predetermined level or more to the fuel injection nozzle 4 through the fuel pipe 4a, so that the fuel is injected and supplied from the nozzle 4 to the diesel engine 3. You.

The fuel injection pump 1 has a drive shaft 5
The drive pulley 2 is attached to the tip of the drive shaft 5. In the middle of the drive shaft 5 is provided a fuel feed pump 6 (developed by 90 degrees in this figure) composed of a vane type pump. A disk-shaped pulsar 7 is attached to the base end side of the drive shaft 5. On the outer peripheral surface of the pulsar 7, missing teeth of the same number as the number of cylinders of the diesel engine 3, that is, four (in total, “eight”) missing teeth are formed at equal angular intervals in this embodiment. Also, between each missing tooth,
Fourteen projections (a total of "56") are formed at equal angular intervals. The base end of the drive shaft 5 is connected to the cam plate 8 via a coupling (not shown).

A roller ring 9 is provided between the pulsar 7 and the cam plate 8. A plurality of cam rollers 10 facing the cam face 8a of the cam plate 8 are mounted in the circumferential direction of the roller ring 9. The cam faces 8 a are provided in the same number as the number of cylinders of the diesel engine 3. The cam plate 8 is a spring 1
1 is urged to engage with the cam roller 10.

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

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

In the pump housing 13 of this embodiment, a delivery valve 3 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.

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.

On 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. In FIG. 1 , in a 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 communicating with each cylinder and constituting an intake system, and an exhaust passage 50 constituting an exhaust system. or,
In the intake passage 49, a turbocharger 5 constituting a supercharger is provided.
One compressor 52 is provided, and a turbine 53 of the turbocharger 51 is provided in the exhaust passage 50.
Further, a waste gate valve 54 is provided in the exhaust passage 50. As is well known, turbocharger 5
Numeral 1 is to rotate the turbine 53 by using the energy of the exhaust gas, and to rotate the compressor 52 coaxially with the turbine 53 to increase the pressure of the intake air. When the intake air is pressurized, high-density air is sent into the main combustion chamber 44, and a large amount of fuel injected through the sub-combustion chamber 45 is burned, so that the output of the diesel engine 3 is increased.
Further, by opening and closing the waste gate valve 54, the boost level of the intake air by the turbocharger 51 is adjusted. Further, in this embodiment, the main combustion chambers 44 pass through the intake passage 49 depending on the degree of the pressure increase of the intake air.
Since the real air amount to be supplied to the air conditioner, that is, the excess air ratio is adjusted, the turbocharger 51 constitutes a real air amount adjusting means.

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. As described above, the EGR passage 56, EG
An EGR device is configured by the R valve 57, the EVRV 58, and the like. When the EGR valve 57 is opened and closed by the EVRV 58, the EGR guided from the exhaust passage 50 to the intake passage 49 through the EGR passage 56.
The amount is adjusted or EGR is cut off. In this embodiment, the excess air ratio in each main combustion chamber 44 is adjusted through the intake passage 49 depending on the amount of EGR as described above. Means are configured.

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.

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

As sensors for detecting the operating state of the diesel engine 3, the following various sensors are provided in addition to the rotation speed sensor 35 described above. That is, near the air cleaner 66 provided at the inlet of the intake passage 49, the temperature of the air taken into the intake passage 49, that is, the intake air temperature THA is detected, and a signal corresponding to the detected value is output. An intake air temperature sensor 72 is provided. In the vicinity of the throttle valve 59, there is provided an accelerator sensor 73 which detects an accelerator opening ACCP corresponding to the engine load from the open / close position of the valve 59 and outputs a signal corresponding to the magnitude of the detected value. I have. In the vicinity of the intake port 55, there is provided an intake pressure sensor 74 which detects the pressure of 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. Have been. 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 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,
A crank angle sensor 76 that outputs a signal corresponding to the rotational position is provided. Further, a transmission (not shown) is provided with a vehicle speed sensor 77 for detecting a vehicle speed (vehicle speed) SPD. The vehicle speed sensor 77 includes a magnet 77a that is rotated by an output shaft of the transmission, and the magnet 77a periodically turns on a reed switch 77b, so that the vehicle speed SP is increased.
A pulse signal corresponding to D is output. The operation state detecting means is constituted by the various sensors 35, 72 to 77 described above.

In addition, in this embodiment, the intake passage 4
An air flow meter 78 as an intake air amount detecting means for detecting an intake air amount VS taken from the outside into the intake passage 49 is provided on the inlet side of the intake passage 9. The air flow meter 78 is composed of, for example, a movable vane type or Karman vortex type sensor.

In this embodiment, the ECU 71 constitutes basic injection amount calculating means, injection amount control means, intake amount learning means, intake amount deviation calculating means, and injection amount correcting means. The ECU 71 has the above-described sensors 3
5, 72 to 77 and the air flow meter 78 are respectively connected. In addition, the ECU 71 controls the sensors 35, 72 to
The electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EVRV 58, and the VSVs 64 and 65 are preferably controlled based on the signals output from the air flow meter 77 and the air flow meter 78.

Next, will be described in accordance with block diagram of Figure 3 shows the structure of the ECU71 described above. 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-described intake air temperature sensor 72, accelerator sensor 73, intake air pressure sensor 74, water temperature sensor 75, and air flow meter 78 in each buffer 8
8, 89, 90, 91 and 92, a multiplexer 93 and an A / D converter 94. Similarly, the input port 85 is provided with the rotation speed sensor 35, the crank angle sensor 76, and the vehicle speed sensor 77 described above.
5 are connected. Then, the CPU 81 controls the sensors 35, 72 to 7 input through the input port 85.
7 and signals from the air flow meter 78 and the like are read as input values. Also, the output port 86 is connected to the electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EV via the respective driving circuits 96, 97, 98, 99, 100, 101.
The RV 58 and the VSVs 64 and 65 are connected to each other. Then, the CPU 81 controls the sensors 35, 72 to 7
7 and the input values read from the air flow meter 78, the electromagnetic spill valve 23, the TCV 33, the glow plug 46, the EVRV 58, and the VSVs 64 and 65 are suitably controlled.

The CPU 81 of this embodiment also has a timekeeping function. 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. 3 for convenience.

Next, will be described in accordance with FIGS. 4-6 for the process operation for the fuel injection amount control and the EGR control performed by the ECU71 described above. FIG. 4 is a flowchart showing the contents of a "fuel injection amount control routine" for controlling the fuel injection amount, among the processing operations executed by the ECU 71. The processing of this routine is periodically executed at predetermined intervals. You.

When the processing shifts to this routine, first, at step 110, based on various signals from the various sensors 35, 73 to 75 and the air flow meter 78, the engine speed NE, the supercharging pressure PiM, the cooling water temperature THW,
The accelerator opening ACCP and the intake air amount VS are read.

Subsequently, at step 120, the currently read engine speed NE and accelerator opening AC
Based on the CP, a basic injection amount Qb according to the operation state of the diesel engine 3 is calculated. The calculation of the basic injection amount is performed according to a predetermined calculation formula. In step 130, the target injection amount Q is calculated by correcting the basic injection amount Qb obtained this time based on the current cooling water temperature THW, the supercharging pressure PiM, and the like. That is, the target injection amount Q is obtained by correcting the basic injection amount Qb according to the cold state or the operating state of the turbocharger 51.

Next, at step 140, a predicted intake air amount VSP suitable for the current operating condition is calculated based on the current engine speed NE and the accelerator opening ACCP. The predicted intake air amount VSP is obtained by referring to a predetermined map.

Thereafter, in step 150, the accelerator opening change amount ΔACCP per unit time is calculated based on the accelerator opening ACCP. The accelerator opening change ΔACCP is the accelerator opening ACCP read this time.
And the accelerator opening ACCP read last time.

In step 160, it is determined whether or not the change ΔACCP in the accelerator opening obtained this time is larger than a predetermined reference value α. here,
If the accelerator opening change amount ΔACCP is not larger than the reference value α, the diesel engine 3
The process proceeds to step 170 on the assumption that it is the time of steady operation with little change in CCP. Then, the processing of steps 170, 180, and 190 for the steady operation is performed.

That is, in step 170, a deviation between the actual intake air amount VS read this time and the predicted intake air amount VSP obtained this time is calculated, and the difference is calculated as the intake air amount deviation ΔV
Set as S. In step 180, the learned intake air amount deviation ΔVSG is determined by learning the intake amount deviation ΔVS determined this time according to the current engine speed NE and the accelerator opening ACCP. Further, the obtained learned intake air amount deviation ΔVSG is temporarily stored in the RAM 83. Further, in step 190, after setting the target injection amount Q obtained this time as the final injection amount QFIN,
Move to step 230.

In step 230, fuel injection is executed based on the final injection amount QFIN obtained this time. That is, by controlling the electromagnetic spill valve 23 based on the final injection amount QFIN, the pressure of the fuel from the fuel injection pump 1 to the fuel injection nozzle 4 is controlled. Thereby, the fuel injection amount from the fuel injection nozzle 4 is controlled. Then, after ending the processing of step 230, the subsequent processing is temporarily ended.

On the other hand, in step 160, when the accelerator opening change amount ΔACCP is larger than the reference value α, it is assumed that the diesel engine 3 is in a transient operation such as during acceleration with a large change in the accelerator opening ACCP. Then, the process proceeds to step 200. Then, the processing of steps 200, 210, 220 and the like for the transient operation is executed.

That is, in step 200, the learned intake air amount deviation ΔVSG learned so far and stored in the RAM 83 is read according to the current engine speed NE and the accelerator opening ACCP. Step 210
, The learned intake air amount deviation ΔVSG read this time is added to the predicted intake air amount VSP obtained according to the current operation state.
And the result of the addition is set as the learned intake air amount VSG. Further, in step 220, the actual intake air amount VS read this time and the learned intake air amount VSG found this time are used.
, The target injection amount Q is corrected and calculated, and the calculation result is set as the final injection amount QFIN. This calculation is performed according to the following formula (1).

[0050] QFIN = (VS / VSG) * Q ... (1) In other words, the ratio of the two as a deviation of the actual intake air quantity VS during the transient operation for learning the intake air amount VS G of steady-state operation (VS
/ VSG) is multiplied by the target injection amount Q to determine the final injection amount QFIN.

Thereafter, in step 230, the fuel injection is executed as described above based on the final injection amount QFIN obtained this time, and the subsequent processing is temporarily terminated. As described above, the fuel injection amount control during the steady operation and the transient operation is performed.

FIG. 5 shows an "EGR control routine" for the EGR control among the processing operations executed by the ECU 71.
5 is a flowchart showing the contents of the processing of this routine. The processing of this routine is periodically executed at predetermined intervals.

When the process proceeds to this routine, first, in step 310, the final injection amount QFIN and the like obtained in the aforementioned "fuel injection amount control routine" are read.
Further, the engine speed NE is read based on the detection value of the engine speed sensor 35.

Subsequently, at step 320, the final injection amount QFIN and the engine speed NE read this time are read.
And the like, the final injection quantity Q after correction according to a predetermined calculation formula.
Calculate FIND.

In step 330, the EGR control amount DFI is determined based on the currently read engine speed NE and the currently obtained corrected final injection amount QFIND.
N is calculated. Here, EGR control amount DFIN is 6
The relationship between the EGR control amount DFIN and the engine speed NE and the corrected final injection amount QFIND is obtained by referring to a predetermined map as shown in FIG. In this map, the EGR control amount DFIN is the corrected final injection amount Q
It is set to decrease as FIND increases. When the corrected final injection amount QFIND becomes large during the transient operation of the diesel engine 3, the EGR control amount DFIN is set to “0” so as to cut off the EGR. Also, the EGR control amount DFIN
Is set to increase as the engine speed NE increases in a certain range of the corrected final injection amount QFIND.

Thereafter, in step 340, it is determined whether the EGR control amount DFIN obtained this time is smaller than a predetermined reference value β. Here, when the EGR control amount DFIN is smaller than the reference value β, in step 350, the EV is set so that the EGR valve 57 is closed.
The drive of the RV 58 is controlled. That is, the EGR is turned off.
Then, the processing of this routine is temporarily ended.

On the other hand, if the EGR control amount DFIN is not smaller than the reference value β in step 340, in step 360, the EGR control amount D
It is determined whether FIN is larger than a predetermined reference value γ (β <γ). Here, if the EGR control amount DFIN is larger than the reference value γ, the process proceeds to step 380. If the EGR control amount DFIN is not larger than the reference value γ, it is determined in step 370 whether or not the EGR valve 57 has been closed in the previous control cycle. If the EGR valve 57 was previously closed in step 370, the EGR is turned off in step 350 as described above, and the processing of this routine is temporarily terminated. Also, the EGR valve 57
If is not closed, the process proceeds to step 380.

Then, step 360 or step 37
In step 380 after shifting from 0, the drive of the EVRV 58 is controlled so that the EGR valve 57 is opened. That is, the EGR is turned on. Then, the processing of this routine is temporarily ended.

That is, steps 340 to 380
In the above, the EGR is switched on / off with a certain degree of hysteresis. As above,
EG calculated based on the corrected final injection amount QFIND and the like
EGR is switched on and off in accordance with the R control amount DFIN, and the EGR amount is controlled. In particular, during the transient operation of the diesel engine 3, the EGR is switched from "on" to "off", that is, the EGR valve 57 is switched from the open state to the closed state, in order to shut off the EGR.

As described above, according to the fuel injection amount control device of this embodiment, when the diesel engine 3 is operating, the basic injection amount Qb is obtained according to the operating state. In addition, the target injection amount Qb is obtained by correcting the basic injection amount Qb in a cold state or according to the operating state of the turbocharger 51. The electromagnetic spill valve 23 of the fuel injection pump 1 is driven and controlled based on the final injection amount QFIN set from the target injection amount Q, so that a required amount of fuel is supplied to each main combustion chamber 44 of the diesel engine 3. And supplied for combustion. Further, the EGR valve 57 of the EGR device is opened and closed according to the operation state at that time, whereby the excess air ratio to be supplied to each main combustion chamber 44 through the intake passage 49 is appropriately adjusted. Further, the air flow meter 78 detects the amount of intake air VS taken into the intake passage 49 from outside according to the operating state at that time. At the time of steady operation in which there is little change in the accelerator opening ACCP, the detected actual intake air amount VS and the predicted intake air amount VSP
Is the engine speed NE at that time.
And the accelerator opening ACCP.

Here, when a transition is made from the steady operation state to the transitional operation state, the EGR valve 57 which has been opened until then is closed in order to increase the excess air ratio to be supplied to the diesel engine 3. . At the same time,
For the fuel injection amount control, the learned intake air amount VSG is calculated based on the learned intake air amount deviation ΔVSG previously learned during the steady operation.
Is required. Then, the target injection amount Q is corrected by the ratio (VS / VSG) of the learned intake amount VSG to the actual intake amount VS, and the final injection amount QFIN is set.
Therefore, during the transient operation of the diesel engine 3, the EGR
When the EGR valve 57 is closed to shut off the air, if the closing delay of the valve 57 occurs, the EGR shutoff is delayed and the intake of air from the outside into the intake passage 49 is delayed. However, in this case, the ratio of the actual intake air amount VS to the learned intake air amount VSG (VS / VSG) is calculated by reflecting the intake air delay. Therefore, the ratio (V
The target injection amount Q is corrected according to (S / VSG), and the amount of fuel supplied to each main combustion chamber 44 is optimized. That is, the fuel injection amount is corrected to decrease in proportion to the decrease in the excess air ratio of the main combustion chamber 44 due to the delay in closing the EGR valve 57. In addition, during a transient operation such as acceleration, the turbocharger 51 also starts to operate. At this time, even if an operation delay occurs in the turbocharger 51,
As in the case of the above-described EGR device, the fuel injection amount is reduced and corrected.

In addition, the learned intake air amount VSG obtained from the learning during the steady operation includes individual differences and changes over time relating to the volume of the main combustion chamber 44 and the intake passage 49, and individual differences and changes over time in the EGR device and the turbocharger 51. The change, the individual difference regarding the detection accuracy of the air flow meter 78, and the change with time are reflected. Therefore, the ratio (V
(S / VSG) reflects the above-mentioned various solid differences and changes over time. In other words, the above ratio (VS / VSG) is obtained by offsetting various solid differences, and is determined following various changes with time. Then, the final injection amount QFIN is also set as a result corrected in accordance with the individual difference and the change with time. Therefore, the fuel injection amount supplied to the main combustion chamber 44 during the transient operation is optimized according to the individual difference and the change with time.

As a result, during transient operation, the fuel injection amount can be accurately corrected in response to the delay in closing the EGR valve 57 and the delay in operating the turbocharger 51. In addition, during the transient operation, the fuel injection amount can be corrected with high accuracy by coping with the individual difference and aging of the intake passage 49 including the EGR device and the turbocharger 51 or the main combustion chamber 44. Further, the fuel injection amount can be corrected with high accuracy by coping with the individual difference and the change with time regarding the detection accuracy of the air flow meter 78. Therefore, in the diesel engine 3 during the transient operation, it is possible to suppress the discharge of smoke due to the excessive injection of fuel, and it is possible to prevent the exhaust emission from deteriorating.

It should be noted that the present invention is not limited to the above-described embodiment, and may be carried out as follows by appropriately changing a part of the configuration without departing from the spirit of the invention. (1) In the above embodiment, the actual intake air amount VS during the steady operation
And the predicted intake air amount VSP, the learned intake air amount deviation ΔVS
G is learned, and the learned intake air amount deviation ΔVSG during transient operation
And the predicted intake air amount VSP are added to obtain the learned intake air amount VSG. On the other hand, the learned intake air amount VSG may be obtained by directly learning the actual intake air amount VS during the steady operation.

(2) In the above embodiment, the diesel engine 3 provided with the EGR device as the substantial air amount adjusting means and the turbocharger 51 is embodied, but the present invention is also embodied in a diesel engine provided with an intake throttle valve. You can also. Alternatively, the present invention can be embodied in a diesel engine provided with any one of an EGR device, a turbocharger, and an intake throttle valve, or an appropriate combination thereof.

(3) In the above embodiment, the diesel engine 3 is embodied as the internal combustion engine, but it may be embodied as a gasoline engine. (4) In the above embodiment, the air flow meter 78 is used as the intake air amount detecting means, but an intake air pressure sensor may be used as the intake air amount detecting means.

(5) In the above embodiment, the diesel engine 3 provided with the turbocharger 51 as the supercharger is embodied. However, the present invention may be embodied as a diesel engine provided with a supercharger as the supercharger.

[0068]

[0069]

Effects of the Invention hand According to the present invention, be adjusted to substantially fraud and mitigating risk intake air amount, such as EGR valve during a transient operation of the internal combustion engine
Or resulting operation delay in stages, der if there is individual difference or aging in the intake system and <br/> intake air amount detecting means or the like comprising such means
Accordingly, the fuel injection amount can be corrected with high accuracy in response to these, and the excellent effect that the deterioration of the exhaust emission can be prevented in advance can be exhibited.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a supercharged diesel engine system according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a fuel injection pump in one embodiment.

FIG. 3 is a block diagram illustrating an electrical configuration of an ECU in one embodiment.

FIG. 4 is a flowchart showing a “fuel injection amount control routine” executed by an ECU in one embodiment.

FIG. 5 is a flowchart illustrating an “EGR control routine” executed by an ECU in one embodiment.

FIG. 6 is a map showing a relationship between an EGR control amount and an engine speed and a corrected final injection amount in one embodiment.

[Explanation of symbols]

1 ... fuel injection pump, 3 ... de I over diesel engine, 49 ...
Inspiratory passage, 5 1 ... data Bochaja, 56 ... EGR passage 57 ... EGR Valve, 58 ... EVR V, 35 ... rotational speed sensor, 73 ... accelerator sensor, 78 ... error Afro chromatography meter, 71 ... EC U.

Continuation of the front page (56) References JP-A-2-301645 (JP, A) JP-A-2-191850 (JP, A) JP-A-4-255546 (JP, A) JP-A-60-1344 (JP) , A) Japanese Utility Model Showa 61-6661 (JP, U) Japanese Utility Model 1-69161 (JP, U) Japanese Utility Model Showa 62-160744 (JP, U) Japanese Utility Model Utility Model 1-166245 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) F02D 41/04 330 F02D 41/02 330

Claims (1)

(57) [Claims] 1. An engine speed and an accelerator operation amount based on an engine operation amount.
And the fuel injection amount is set
Fuel injection system for an internal combustion engine in which the intake air amount is adjusted
A control device, and the intake air amount detecting means for detecting the intake air amount, a steady state when said internal combustion engine is to be in the steady operating condition
An intake air amount calculation method for calculating an intake air amount based on an engine operating state.
And whether the internal combustion engine is in a steady operation state or a transient operation state.
Determining means for determining whether the internal combustion engine is in a steady operation state
The detected intake air amount and the calculated steady-state intake
A learning means for learning a deviation between the intake air amount and the calculated steady-state intake air amount;
A steady-state intake air amount correcting means for correcting the internal combustion engine in a transient operation state.
The detected intake air amount and the corrected steady-state intake air amount
And the fuel injection set based on the comparison result.
Internal combustion engine provided with fuel injection amount correction means for correcting the injection amount
Fuel injection amount control device.