JPH06173741A - Maximum fuel injection quantity control device - Google Patents

Abstract

PURPOSE:To improve acceleration performance and also reduce smoke by correcting a maximum fuel injection quantity to the increasing side in compliance with an acceleration state. CONSTITUTION:A fuel injection pump 2 is provided with a boost controller 22 for correcting a maximum fuel injection quantity to the increasing side based on the relationship between the supercharging pressure introduced into a supercharging pressure chamber 23 along with the operation of a turbocharger 10 and the pressure introduced into a negative pressure chamber 24, an EVRV 17 for controlling the negative pressure to be introduced into the negative pressure chamber, and VSVs 15 and 27 for selectively introducing negative pressure into the negative pressure chamber 24. In an ECU 47, the opening and closing of the EVRV 17, VSVs 15 and 27 are controlled. In addition, in the ECU 47, when the quick start of an automobile is judged, the opening degree of the EVRV 17 is controlled based on the rising rate of the supercharging pressure obtained by an intake air pressure sensor 44, and the negative pressure introduced into the negative pressure chamber 24 for unit time is adjusted, gradually correcting a maximum fuel injection quantity to the increase side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a maximum fuel injection amount control device for a diesel engine equipped with a supercharger such as a turbocharger. Specifically, the maximum fuel injection amount of a diesel engine with a supercharger is designed so that the maximum fuel injection amount at full load is controlled by operating the fuel injection amount adjustment mechanism in the fuel injection pump according to the boost pressure, etc. The present invention relates to a control device.

[0002]

2. Description of the Related Art Conventionally, in a diesel engine equipped with a supercharger such as a turbocharger, in order to reliably increase the engine output as the supercharging pressure increases, the fuel injection amount to be supplied to the diesel engine has to be increased. Control is generally performed according to the boost pressure. Further, as a fuel injection pump used in a diesel engine, a boost altitude compensation compensation stopper (BACS) as a fuel injection amount adjusting mechanism that controls the maximum fuel injection amount according to supercharging pressure in the engine. Those equipped with are known. As is well known, the BACS is provided with a supercharging pressure chamber and a negative pressure chamber which are vertically divided by a diaphragm. Further, the diaphragm is connected to the governor mechanism via a stopper rod. Then, the diaphragm is displaced by the relationship between the supercharging pressure introduced into the supercharging pressure chamber and the pressure introduced into the negative pressure chamber, and the stopper rod is moved up and down. The maximum fuel injection amount from the injection pump is determined. Therefore,
When the accelerator lever provided on the fuel injection pump is fully opened by the driver, that is, when the diesel engine is fully loaded, fuel is pumped from the fuel injection pump to the diesel engine based on the maximum fuel injection amount determined by BACS. And it is jetted.

A technique for controlling the maximum fuel injection amount of a diesel engine with a supercharger by using a fuel injection pump having the above-mentioned BACS has already been disclosed in JP-A-2-61330. It is disclosed. In this conventional technique, the supercharging pressure of the diesel engine by the turbocharger and the original density of the air drawn into the diesel engine, that is, the atmospheric pressure are detected. When the supercharging pressure is lower than a predetermined value (200 mHg) and is relatively small and the atmospheric pressure is higher than the predetermined value (680 mHg), the negative pressure switching valve is opened to introduce the negative pressure into the negative pressure chamber. It is supposed to be done. As a result, the diaphragm is displaced, the stopper rod is moved downward, the governor mechanism is operated, and the maximum fuel injection amount from the fuel injection pump is increased and corrected.

Therefore, since the atmospheric pressure is secured and a sufficient air density is obtained on a flat ground, the negative pressure chamber is kept until the supercharging pressure introduced into the supercharging pressure chamber rises above a predetermined value. The maximum fuel injection amount is increased and corrected by the negative pressure introduced.
As a result, the output of the diesel engine at full load is increased and the starting characteristics of the vehicle are improved. On the other hand, at high altitudes, the atmospheric pressure is low and sufficient air density cannot be obtained. It is not introduced and the maximum fuel injection amount is not increased and corrected. as a result,
When the diesel engine is fully loaded, excessive fuel injection is prevented, and smoke from the diesel engine is prevented from occurring.

[0005]

However, in the above-mentioned prior art, the predetermined value of the supercharging pressure, which is a reference for opening the negative pressure switching valve, is merely an absolute value. Therefore, when the atmospheric pressure is equal to or higher than the predetermined value, the negative pressure switching valve is immediately opened and the large negative pressure is introduced into the negative pressure chamber of the BACS at once by only the supercharging pressure being equal to or lower than the predetermined value. It was decided.
Therefore, for example, when the diesel engine is under full load and the negative pressure switching valve is opened in an attempt to start the vehicle on level ground, the maximum fuel injection amount in the fuel injection pump is increased at once from the beginning. become. As a result, although the diesel engine can secure a sufficient output to some extent, the increase in the maximum fuel injection amount may not match the acceleration state of the vehicle. In other words, when the vehicle starts
The vehicle speed gradually increases, and the supercharging pressure gradually increases accordingly. Therefore, if the maximum fuel injection amount is increased at once from the start of the vehicle, there is a possibility that fuel will be injected to the diesel engine more than necessary, and there is a problem in that smoke is generated in the diesel engine. It was

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to introduce the supercharging pressure introduced into the supercharging pressure chamber with the operation of the supercharger and the negative pressure chamber. With a fuel injection amount adjustment mechanism that corrects the maximum fuel injection amount from the fuel injection pump by displacing the diaphragm in relation to the pressure, the maximum fuel injection amount is increased by adapting to the acceleration state of the vehicle. It is an object of the present invention to provide a maximum fuel injection amount control device for a diesel engine with a supercharger, which can be corrected and can achieve both improvement of the starting acceleration performance of the vehicle and reduction of smoke.

[0007]

In order to achieve the above object, in the present invention, as shown in FIG. 1, a diesel engine M2 mounted on a vehicle M1 as a drive source.
And a supercharger M3 for increasing the pressure of air taken into the diesel engine M2, and a diesel engine M
2, a fuel injection pump M4 for sending fuel under pressure, a supercharging pressure chamber M6 and a negative pressure chamber M partitioned by a diaphragm M5.
Fuel injection by displacing the diaphragm M5 according to the relationship between the supercharging pressure introduced into the supercharging pressure chamber M6 and the pressure introduced into the negative pressure chamber M7 when the supercharger M3 operates. The fuel injection amount adjusting mechanism M8 for increasing and correcting the maximum fuel injection amount from the pump M4, and the opening degree is adjusted to control the negative pressure introduced into the negative pressure chamber M7 of the fuel injection amount adjusting mechanism M8. Negative pressure control valve M9, operating state detecting means M10 for detecting operating states of vehicle M1 and diesel engine M2, and supercharging pressure detecting means M11 for detecting supercharging pressure obtained by supercharger M3. The supercharging pressure increase rate calculating means for calculating the increase rate of the supercharging pressure detected by the supercharging pressure detecting means M11 when it is determined that the vehicle M1 is starting based on the detection result of the driving state detecting means M10. M12 and its Depending on the increase rate of the supercharging pressure calculated by the pressure increase rate calculating unit M12, the negative pressure control valve M9 to adjust the negative pressure amount per unit introduced time the negative pressure chamber M7
It is intended to include the negative pressure control valve control means M13 for controlling the opening degree of the.

[0008]

According to the above construction, as shown in FIG. 1, when the diesel engine M2 is in operation, the supercharger M3 operates to boost the pressure of the air taken into the diesel engine M2. At this time, the supercharging pressure increased to a certain level is introduced into the supercharging pressure chamber M6 of the fuel injection amount adjusting mechanism M8, whereby the diaphragm M5 is displaced and the maximum fuel injection amount from the fuel injection pump M4 is increased. Will be corrected.

When the vehicle M1 starts moving, the following control is performed. That is, in the supercharging pressure increase rate calculation means M12,
When it is determined that the vehicle M1 is starting based on the detection result of the driving state detecting means M10, the increase rate of the supercharging pressure detected by the supercharging pressure detecting means M11 is calculated. That is, the increase rate of the supercharging pressure that reflects the acceleration state from the start of the vehicle M1 is calculated. Then, in the negative pressure control valve control means M13,
The opening degree of the negative pressure control valve M9 is controlled to adjust the negative pressure amount per unit time introduced into the negative pressure chamber M7 of the fuel injection amount adjusting mechanism M8 according to the calculated increase rate of the supercharging pressure. To be done. That is, the opening degree of the negative pressure control valve M9 is controlled according to the increase rate of the supercharging pressure that reflects the acceleration state from the start of the vehicle M1.

Therefore, when the vehicle M1 starts, the supercharger M
Negative pressure is gradually introduced into the negative pressure chamber M7 according to the rate of increase of the supercharging pressure reflecting the acceleration state of the vehicle M1 until the supercharging pressure rises to a certain level by the operation of 3. Therefore, until the diaphragm M5 can be displaced by the supercharging pressure, the diaphragm M5 is gradually displaced by the change in the negative pressure amount that reflects the acceleration state of the vehicle M1, and the maximum fuel injection from the fuel injection pump M4 is performed. The amount is gradually increased and corrected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment embodying a maximum fuel injection amount control device for a diesel engine with a supercharger according to the present invention will be described in detail below with reference to FIGS.

FIG. 2 shows a schematic structure of a diesel engine system with a supercharger mounted on an automobile in this embodiment. This system has a diesel engine 1
Fuel injection pump 2 for pumping fuel to the engine 1
It has and.

The engine body 3 constituting the diesel engine 1 is composed of a plurality of cylinders, and fuel injection nozzles (not shown) are provided corresponding to the combustion chambers of the respective cylinders. An intake manifold 4 forming an intake system and an exhaust manifold 5 forming an exhaust system are connected to the engine body 3. The intake manifold 4 has an intake passage 6
However, exhaust passages 7 are connected to the exhaust manifolds 5, respectively. A compressor 8 is provided upstream of the intake passage 6, and a turbine 9 is provided downstream of the exhaust passage 7. The compressor 8 and the turbine 9 constitute a turbocharger 10 as a supercharger. As is well known, the turbocharger 10 rotates the turbine 9 by the exhaust gas flowing through the exhaust passage 7,
The rotational force causes the compressor 8 to rotate, thereby boosting the pressure of the air taken into each combustion chamber of the engine body 3 through the intake passage 6 and the intake manifold 4.

In order to recirculate a part of the exhaust gas discharged from the engine body 3 to intake air taken into the engine body 3, that is, to perform exhaust gas recirculation (EGR), the intake passage 6 and the exhaust gas are exhausted. An EGR passage 11 that connects the both 6 and 7 is provided between the passage 7 and the passage 7. An EGR valve 12 that opens and closes the EGR passage 11 is provided in the middle of the EGR passage 11. And these E
With the GR passage 11 and the EGR valve 12, the EGR device 13
Is configured. The EGR valve 12 is a diaphragm type negative pressure operated valve. As is well known, the EGR valve 12 is
A valve body 12a for opening and closing the R passage 11, a diaphragm 12b connected to the valve body 12a, a negative pressure chamber 12c partitioned by the diaphragm 12b, and a spring 12d arranged in the negative pressure chamber 12c for urging the diaphragm 12b. And the like. When the negative pressure is not introduced into the negative pressure chamber 12c, the diaphragm 12b moves to the spring 12
The valve body 12a is urged by d to be placed at a position where the EGR passage 11 is closed. That is, the EGR valve 12 is closed. On the other hand, when the negative pressure is introduced into the negative pressure chamber 12c, the diaphragm 12b is pulled and displaced by the negative pressure, and the valve body 12a is arranged at a position where the EGR passage 11 is opened. That is, the EGR valve 12 is opened.

The negative pressure chamber 12c of the EGR valve 12 is connected to a first vacuum switching valve (first VSV) 15 through a negative pressure passage 14. First VS
V15 is a three-way solenoid valve having an input port, an output port, and an atmospheric port, and one end of the negative pressure passage 14 is connected to the output port. Further, the input port of the first VSV 15 is connected to the output port of an electric vacuum regulating valve (EVRV) 17 as a negative pressure control valve through a negative pressure passage 16. A known vacuum damper 18 is provided in the middle of the negative pressure passage 16. The EVRV 17 is a solenoid valve whose opening is adjusted by duty control, and its input port is connected through a negative pressure passage 19 to a vacuum pump 20 which is a negative pressure source. Vacuum pump 2
0 is drive-coupled to the crankshaft of the engine body 3 and is driven in conjunction with the operation of the engine body 3
Supply negative pressure to VRV17.

When the first VSV 15 is turned on, the negative pressure chamber 12c of the EGR valve 12 is moved to the negative pressure passage 1
4, through the first VSV 15 and the negative pressure passage 16, etc.,
It is connected to the output port of VRV17. At this time, the negative pressure supplied from the vacuum pump 20 to the EVRV 17 is the negative pressure passage 1 by opening the EVRV 17.
6, through the first VSV 15 and the negative pressure passage 14, etc.
It is supplied to the negative pressure chamber 12c of the R valve 12. Further, the vibration of the negative pressure supplied to the negative pressure chamber 12c at this time is smoothed by the action of the vacuum damper 18. On the other hand, the first V
When the SV 15 is turned off, the negative pressure chamber 12c of the EGR valve 12 is opened to the atmosphere through the negative pressure passage 14.

In addition, the engine body 3 is provided with a water temperature sensor 41 for detecting the temperature (cooling water temperature) THW of the cooling water. The fuel injection pump 2 is a distribution type and is drivingly connected to a crankshaft of the engine body 3. As is well known, a drive shaft is provided inside the fuel injection pump 2, and the drive shaft is connected to the plunger via a cam mechanism. And
When the drive shaft of the fuel injection pump 2 is rotated in conjunction with the crank shaft, the plunger is reciprocated by the same number as the number of cylinders of the engine body 3 to discharge fuel during one rotation of the drive shaft. Fuel is pumped to the fuel injection nozzle for each cylinder.

The fuel injection pump 2 includes an accelerator lever 2 which is rotated in association with the operation of an accelerator pedal (not shown).
1 is provided. The accelerator lever 21 is connected to a spill ring (not shown) on the plunger. Then, by appropriately changing the rotational position of the accelerator lever 21, that is, the accelerator lever opening ACCP, the position of the spill ring is changed and the effective stroke of the plunger is changed, so that the maximum fuel injection from the fuel injection pump 2 is changed. The quantity is determined.

A lever sensor 42, which is a rotary position sensor for detecting the accelerator lever opening ACCP, is provided near the accelerator lever 21. In this lever sensor 42, the Alcel lever 21
Accelerator lever opening ACC with full opening of "100%"
P is detected. Further, the fuel injection pump 2 is provided with a rotation speed sensor 43 for detecting the rotation speed of the crankshaft of the engine body 3, that is, the engine rotation speed NE from the rotation of the drive shaft thereof.

The fuel injection pump 2 has a boost altitude compensation stopper (which constitutes a fuel injection amount adjusting mechanism for controlling the maximum fuel injection amount according to the boost pressure PiM in the engine body 3). BA
CS, hereinafter simply referred to as "boocon") 22 is provided. As is well known, the boocon 22 includes a diaphragm 22a, and two chambers divided by the diaphragm 22a into upper and lower parts. Further, one end of a stopper rod 22b is fixed to the diaphragm 22a, and the rod 22b is connected to the spill ring described above via a governor mechanism (not shown). here,
The upper chamber partitioned by the diaphragm 22a is a supercharging pressure chamber 23 into which supercharging pressure is introduced, and the lower chamber is a negative pressure chamber 24 into which negative pressure or atmospheric pressure is introduced. Then, the diaphragm 22a is displaced by the relationship between the pressure in the supercharging pressure chamber 23 and the pressure in the negative pressure chamber 24. Therefore, the vertical movement of the stopper rod 22b, which is determined by the displacement of the diaphragm 22a, restricts the movement of the spill ring in the fuel increasing direction and determines the maximum fuel injection amount from the fuel injection pump 2.

Since the detailed configuration of the boocon 22 is basically the same as that disclosed in the prior art (Japanese Patent Laid-Open No. 2-61330), a detailed description thereof will be omitted here.

The boost pressure chamber 23 of the boocon 22 communicates with the intake passage 6 through the boost pressure passage 25. As a result, the boost pressure boosted by the compressor 8 is introduced into the boost pressure passage 25. Further, the negative pressure chamber 24 of the boocon 22 is connected to the second VSV 27 through the negative pressure passage 26. The second VSV 27 is a three-system solenoid valve having an input port, an output port and an atmosphere port, and one end of the negative pressure passage 26 is connected to the output port. The input port of the second VSV 27 is connected to the output port of the EVRV 17 through the negative pressure passage 28.

Then, when the second VSV 27 is turned on, the negative pressure chamber 24 of the boocon 22 is moved to the negative pressure passage 26,
Through the second VSV 27 and the negative pressure passage 28, the EVRV
It is connected to 17 output ports. At this time, the negative pressure supplied from the vacuum pump 20 to the EVRV 17 is EV
When the RV 17 is opened, it is supplied to the negative pressure chamber 24 of the boocon 22 through the negative pressure passage 28, the second VSV 27 and the negative pressure passage 26. On the other hand, when the second VSV 27 is turned off, the negative pressure chamber 24 of the boocon 22 becomes
It is opened to the atmosphere through the negative pressure passage 26.

In this embodiment, the supercharging pressure passage 25 described above is used.
In order to detect the supercharging pressure PiM in (1) and the control negative pressure CNP in the negative pressure passage 16, an intake pressure sensor 44 constituting a supercharging pressure detecting means is provided. Also, boost pressure PiM
A third VSV 29 is provided in order to selectively detect the control negative pressure CNP by the intake pressure sensor 44.
The third VSV 29 is a three-way solenoid valve having two input ports and one output port, one input port is connected to the supercharging pressure passage 25 through the communication passage 30, and the other input port is It is connected to the negative pressure passage 16 through the communication passage 31. The remaining output ports are connected to the intake pressure sensor 44 through the communication passage 32.

When the third VSV 29 is turned on, the intake pressure sensor 44 causes the communication passage 32, the third VS.
It communicates with the supercharging pressure passage 25 through the V 29 and the communication passage 30. As a result, the intake pressure sensor 44 detects the supercharging pressure PiM applied to the supercharging pressure passage 25. Further, the intake pressure sensor 44 is turned off by turning off the third VSV 29.
Is communicated with the negative pressure passage 16 through the communication passage 32, the third VSV 29, and the communication passage 31. As a result, the intake pressure sensor 44 detects the control negative pressure CNP applied to the negative pressure passage 16.

In this embodiment, in addition to the water temperature sensor 41, the lever sensor 42, the rotation speed sensor 43, etc., as the operating state detecting means of the diesel engine 1, the running speed (vehicle speed) SPD of the vehicle is detected. Vehicle speed sensor 4
5 are provided. The vehicle speed sensor 45 is provided in an automatic transmission (not shown), and detects the vehicle speed SPD from the rotation of the gear of the automatic transmission.
Further, the automatic transmission is provided with a shift position sensor 46 which outputs a signal instructing the shift position signal ShP.

In this embodiment, the EVR described above is used.
Each of the V17 and the VSVs 15, 27, 29 is drive-controlled by an electronic control unit (hereinafter simply referred to as "ECU") 47. In this example, the EC
U47 constitutes a boost pressure increase rate calculation means and a negative pressure control valve control means. The ECU 47 is a central processing unit (C
PU) and a predetermined control program or the like,
It is configured as a logical operation circuit in which various memories that temporarily store the operation results of the CPU and the like, and these units, an external input circuit, an external output circuit, and the like are connected by a bus. The external input circuit of the ECU 47 includes the water temperature sensor 41, the lever sensor 42, and the rotation speed sensor 4 described above.
3, an intake pressure sensor 44, a vehicle speed sensor 45, a shift position sensor 46 and the like are connected to each other. Also, the ECU 4
The external output circuit of No. 7 has the above-mentioned EVRV17 and each V
SV15, 27, 29 etc. are respectively connected. Since the detailed electrical configuration of the ECU 47 is well known, its description is omitted here.

Next, the contents of the processing operation of the maximum fuel injection amount control executed by the ECU 47 in the maximum fuel injection amount control device constructed as described above will be explained.
3 and 4 show "atmospheric pressure learning /
It is a flowchart explaining an "EGR / BACS control routine", which is executed at predetermined time intervals.

When the processing shifts to this routine, first, at step 101, the cooling water temperature THW and the accelerator lever opening A are obtained based on the signals from the various sensors 41 to 46.
The CCP, the engine speed NE, the supercharging pressure PiM, the control negative pressure CNP, the vehicle speed SPD, and the shift position signal ShP are read.

Next, at step 102, the region of the present operating state is calculated based on the accelerator lever opening ACCP and the engine speed NE which have been read this time.
That is, based on the accelerator lever opening ACCP and the engine speed NE, it is calculated whether or not the current operating region is the “BACS control region” in which the boocon 22 should control the maximum fuel injection amount. Further, whether the EGR device 13 is in the “EGR control region” in which the EGR flow rate should be controlled, or the EG
It is calculated whether or not it is the “atmospheric pressure learning region” in which the atmospheric pressure PA should be learned without controlling the R flow rate. As shown in FIG. 5, this calculation is performed with reference to a map which is predetermined by the relationship between the engine speed NE and the accelerator lever opening ACCP and is stored in the memory.

Then, in step 103, it is judged whether or not the result of the area calculation is the "atmospheric pressure learning area". If the result of the area calculation is the "atmospheric pressure learning area", the process proceeds to step 200 and learning control of the atmospheric pressure PA is executed.

That is, the second VSV 27 and the third VSV 2
9 and 9 are turned off, and the first VSV 15 is turned on. Further, the EVRV 17 is fully closed to make its output negative pressure zero (atmospheric pressure PA). As a result, the intake pressure sensor 44
The atmospheric pressure PA acts through the EVRV 17, the communication passage 31, the third VSV 29 and the communication passage 32, and the intake pressure sensor 44 detects the atmospheric pressure PA. Then, in the ECU 47, the detected atmospheric pressure P
Learning control of the size A is executed. Here, detailed description of the processing content for the learning control of the atmospheric pressure PA will be omitted. Then, after the processing of step 200 is completed, the subsequent processing is once completed.

On the other hand, in step 103, when the result of the area calculation is not the "atmospheric pressure learning area", the process proceeds to step 104 and it is determined whether or not the result of the area calculation is the "EGR control area". . Here, if the result of the area calculation is the “EGR control area”, step 300
Then, the normal EGR control is executed.

That is, the second VSV 27 and the third VSV 2
9 and 9 are turned off, and the first VSV 15 is turned on. Further, the opening degree of the EVRV 17 is duty controlled. As a result, in the EVRV 17, the negative pressure from the vacuum pump 20 is adjusted and output as the control negative pressure CNP. Then, the control negative pressure CNP passes through the negative pressure passage 16, the first VSV 15 and the negative pressure passage 14 and then the EGR valve 1
2 is introduced into the negative pressure chamber 12c, and the EGR valve 12 is opened with an opening degree according to the magnitude of the control negative pressure CNP. That is, E
The EGR flow rate flowing through the GR passage 11 is controlled. At this time, the intake pressure sensor 44 passes through the communication passage 31, the third VSV 29, and the communication passage 32 through the control negative pressure CN.
Since P acts, the intake pressure sensor 44 detects the control negative pressure CNP. Then, in the ECU 47,
Based on the detected control negative pressure CNP, EVRV17
The duty control of the opening of is feedback-controlled.
Here, detailed description of the processing contents of the EGR control is omitted. Then, after finishing the process of step 300,
The subsequent processing is once ended.

On the other hand, in step 104, when the result of the area calculation is not the "EGR control area", "BAC"
Assuming that it is the “S control area”, the process proceeds to step 105. Then, in step 105, the second VS
V27 and the third VSV29 are turned on, and the first V
The SV15 is turned off. As a result, EVRV17
Is connected to the negative pressure chamber 24 of the boocon 22 through the negative pressure passage 28, the second VSV 27 and the negative pressure passage 26. In addition, the intake pressure sensor 44 includes a supercharging pressure passage 2
5, the supercharging pressure PiM acts through the communicating passage 30, the third VSV 29, and the communicating passage 32, and the intake pressure sensor 44 detects the supercharging pressure PiM.

Next, in step 106, it is determined whether or not the vehicle is starting. This judgment is the vehicle speed SP
When D is a predetermined value or less, the engine speed NE is a predetermined value or less, and the accelerator lever opening ACCP is a predetermined value or less, the vehicle is started. If the determination here is not at the start, the subsequent processing is terminated as it is. If the determination is that the vehicle is starting, the process proceeds to step 107.

In step 107, the increase rate per unit time, that is, the accelerator lever opening increase rate ΔACCP is calculated based on the accelerator lever opening ACCP. Subsequently, in step 108, it is determined whether or not the vehicle is suddenly started. This determination is performed suddenly mainly when the accelerator lever opening increase rate ΔACCP is equal to or greater than a predetermined value. Then, if the determination here is not a rapid start, the subsequent processing is terminated as it is. If this determination is a sudden start, the process proceeds to step 109.

In step 109, an increase rate per unit time, that is, a vehicle speed increase rate ΔSPD is calculated based on the vehicle speed SPD. Then, in step 110,
It is determined whether or not the diesel engine 1 is racing. This determination is mainly made during racing when the vehicle speed increase rate ΔSPD is less than or equal to a predetermined value. Then, if the determination here is at the time of racing, the subsequent processing is temporarily terminated. If the determination is not during racing, the process proceeds to step 111.

In step 111, the rate of increase per unit time, that is, the engine speed increase rate ΔNE is calculated based on the engine speed NE. Next, at step 112, it is determined whether the engine speed increase rate ΔNE is equal to or greater than a predetermined value α. If the engine speed increase rate ΔNE is not equal to or greater than the predetermined value α, it is determined that the vehicle has not been suddenly started suddenly, and the subsequent processing is temporarily terminated. If the engine speed increase rate ΔNE is greater than or equal to the predetermined value α, it is determined that the vehicle has suddenly started suddenly, and the process proceeds to step 113.

In step 113, the elapsed time ts after the sudden start of the automobile is reliably performed is counted up. Then, in step 114, it is determined whether or not the elapsed time ts has reached the predetermined time t1.

If the elapsed time ts has not reached the predetermined time t1 in step 114, it is determined that the supercharging pressure PiM has not risen sufficiently, and step 115
Move to. Then, in step 115, the negative pressure command value BACSP for controlling the control negative pressure CNP to be introduced into the negative pressure chamber 24 of the boocon 22 is calculated, and the subsequent processing is once ended. Here, an extremely small predetermined value β1 is added to the negative pressure command value BACSP obtained in the previous control cycle, and the addition result is set as a new negative pressure command value BACSP. When the process of step 115 is first performed, the negative pressure command value BACSP of the previous time is “0”, and therefore the negative pressure command value BACSP becomes the predetermined value β1. Then, each time the processing of step 115 is repeated until the elapsed time ts reaches the predetermined time t1, the negative pressure command value BACSP is gradually and gradually increased by the predetermined value β1.

On the other hand, when the elapsed time ts reaches the predetermined time t1 in step 114, it is determined that the boost pressure PiM has risen to some extent, and in step 116, the unit is determined based on the boost pressure PiM. The rate of increase per unit time, that is, the boost pressure increase rate ΔPiM is calculated. That is, the increase rate of the supercharging pressure PiM according to the acceleration state from the start of the vehicle is calculated.

Subsequently, in step 117, the magnitude of the boost pressure increase rate ΔPiM is determined. Here, when the boost pressure increase rate ΔPiM is less than or equal to the relatively small predetermined value ΔP1, in step 118, the negative pressure command value BA
The CSP is calculated, and the subsequent processing is ended once. Here, a predetermined value β2 (β2 is added to the previous negative pressure command value BACSP.
> Β1) is added, and the addition result is a new negative pressure command value B
Set as ACSP. After that, the boost pressure increase rate ΔP
When iM is equal to or smaller than the predetermined value ΔP1, the negative pressure command value BACS is returned every time the process of step 118 is repeated.
P is gradually increased slightly by a predetermined value β2.

If it is determined in step 117 that the supercharging pressure increase rate ΔPiM is greater than the predetermined value ΔP1 and less than or equal to the relatively large predetermined value ΔP2 (ΔP2> ΔP1), the negative pressure command is issued in step 119. Value BACSP
Is calculated, and the subsequent processing is once terminated. Here, a predetermined value β3 (β3> β2) is added to the previous negative pressure command value BACSP.
> Β1) is added, and the addition result is a new negative pressure command value B
Set as ACSP. After that, the boost pressure increase rate ΔP
When iM is larger than the predetermined value ΔP1 and is equal to or smaller than the predetermined value ΔP2, the negative pressure command value BACSP is gradually increased by the predetermined value β3 every time the process of step 119 is repeated.

On the other hand, when the boost pressure increase rate ΔPiM is larger than the predetermined value ΔP2 in step 117, the negative pressure command value BACSP is calculated in step 120, and the subsequent processing is temporarily terminated. Here, a predetermined value β4 (β4>β3> β2) is added to the previous negative pressure command value BACSP.
> Β1) is added, and the addition result is a new negative pressure command value B
Set as ACSP. After that, the boost pressure increase rate ΔP
When iM is larger than the predetermined value ΔP2, the negative pressure command value BAC is repeated each time the processing of step 120 is repeated.
SP is gradually and slightly increased by a predetermined value β4.

As described above, according to the maximum fuel injection amount control device of this embodiment, the learning control of the atmospheric pressure PA and the normal EGR control are respectively performed according to the operating region of the diesel engine 1, and the BACS is performed. The negative pressure command value BACSP is obtained by the control. Then, in the ECU 47, the EV is calculated based on the obtained negative pressure command value BACSP.
The opening degree of the RV 17 is duty controlled. This allows
In the EVRV 17, the negative pressure supplied from the vacuum pump 20 is adjusted based on the negative pressure command value BACSP, and is output as the control negative pressure CNP according to the negative pressure command value BACSP. Then, the control negative pressure CNP is the boocon 22.
Is introduced into the negative pressure chamber 24, and the boocon 22 operates in accordance with the control negative pressure CNP to determine the maximum fuel injection amount in the fuel injection pump 2.

Moreover, in this embodiment, when the vehicle is suddenly started from the "BACS control range" of the diesel engine 1, the negative pressure command value BACSP is set until the boost pressure PiM rises to a sufficient level. Is gradually increased from "0" by a predetermined value β1. Also, the boost pressure Pi
When M reaches a certain level, the negative pressure command value BACSP is gradually increased by a predetermined value β2, a predetermined value β3, or a predetermined value β4 according to the magnitude of the boost pressure increase rate ΔPiM that reflects the acceleration state of the vehicle. It Then, in the ECU 47,
Based on the negative pressure command value BACSP obtained in this way,
The duty control of the opening degree of the EVRV 17 is performed.

Therefore, when the car is suddenly started,
A large control negative pressure CN is applied to the negative pressure chamber 24 of the boocon 22 at a time.
Instead of introducing P, the control negative pressure CNP is gradually and gradually increased and introduced into the negative pressure chamber 24 in anticipation of a delay in the rising of the supercharging pressure PiM. Subsequently, the control negative pressure CNP is gradually increased at a rate of increase corresponding to the boost pressure increase rate ΔPiM that reflects the acceleration state of the vehicle, and is introduced into the negative pressure chamber 24. And the control negative pressure CNP
The boo-con 22 operates in accordance with the change of the above, and the maximum fuel injection amount to be pressure-fed from the fuel injection pump 2 to the diesel engine 1 is gradually increased and corrected.

Here, in this embodiment, the accelerator lever opening ACCP, the engine speed NE, the vehicle speed SPD, the supercharging pressure PiM, and the negative pressure command value BACS when the vehicle suddenly starts.
An example of the behavior of the increase correction amount of P and the maximum fuel injection amount is shown in the time chart of FIG. As is clear from this figure, the accelerator lever opening ACCP is fully opened (1
00%), the increase correction amount of the negative pressure command value BACSP becomes the predetermined value β1 until the predetermined time t1 elapses in the initial stage of the rapid start, and thereafter, the boost pressure increase rate Δ
The increase correction amount becomes a predetermined value β3 according to PiM. Then, the change in the maximum fuel injection amount is caused by first changing the accelerator lever 2
After rising up by the amount corresponding to the operation of 1, the predetermined value β1
And the value is gradually increased with two different increase rates determined by the predetermined value β3. Then, according to such a change in the maximum fuel injection amount, the engine speed NE and the vehicle speed SPD
You can see that is rising smoothly.

As a result of such control, the excessive injection of fuel to the diesel engine 1 is prevented and the occurrence of smoke is suppressed until the boost pressure PiM reaches a certain level at the initial stage of sudden start. be able to. Further, after the sudden start, the acceleration state of the vehicle is predicted by the magnitude of the boost pressure increase rate ΔPiM, and the increase correction of the maximum fuel injection amount is performed with the increase speed adapted to the acceleration state. It is possible to improve the start-up acceleration performance of the vehicle while suppressing the generation of smoke from the diesel engine 1. That is, it is possible to achieve both improvement of the starting acceleration performance of the automobile and reduction of smoke. Further, since the increase correction of the maximum fuel injection amount is adapted to the acceleration state, it is possible to prevent a sudden torque change in the diesel engine 1 and suppress acceleration shock or the like at the time of sudden start. .

The present invention is not limited to the above-described embodiment, but may be implemented as follows with a part of the configuration appropriately modified without departing from the spirit of the invention. (1) In the above embodiment, the increase correction amount of the maximum fuel injection amount is uniformly set to the predetermined value β1 at the initial stage of the rapid start, and thereafter, the increase correction amount is increased in accordance with the magnitude of the boost pressure increase rate ΔPiM. I set the minutes. On the other hand, from the initial stage of sudden start, the increase correction amount of the maximum fuel injection amount is set to the supercharging pressure increase rate ΔPi.
The size may be set according to the size of M.

(2) In the above embodiment, the maximum fuel injection amount is controlled as described above when the vehicle suddenly starts, but the maximum fuel injection amount may be simply controlled when the vehicle starts.

(3) In the above embodiment, the diesel engine 1 having the turbocharger 10 as a supercharger is embodied, but it may be embodied as a diesel engine having a supercharger or other supercharger. .

[0054]

As described above in detail, according to the present invention, in the fuel injection amount adjusting mechanism, the supercharging pressure introduced into the supercharging pressure chamber along with the operation of the supercharger and the negative pressure chamber are introduced. The maximum amount of fuel injection from the fuel injection pump is increased and corrected by displacing the diaphragm according to the relationship with the pressure applied. Further, when the vehicle starts, by controlling the opening degree of the negative pressure control valve according to the rate of increase in supercharging pressure,
The amount of negative pressure introduced into the negative pressure chamber per unit time is adjusted. Therefore, at the time of starting, until the boost pressure rises to a certain level, the amount of negative pressure introduced into the negative pressure chamber is controlled according to the rate of increase of the boost pressure that reflects the acceleration state of the vehicle, and the maximum The fuel injection amount is gradually increased and corrected.
As a result, the maximum fuel injection amount can be increased and corrected according to the acceleration state of the vehicle, and the excellent effect that both the starting acceleration performance of the vehicle and the reduction of smoke can be achieved is exhibited.

[Brief description of drawings]

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

FIG. 2 is a schematic configuration diagram showing a diesel engine system with a supercharger in an embodiment embodying the present invention.

FIG. 3 is a flowchart illustrating an “atmospheric pressure learning / EGR / BACS control routine” executed by the ECU in one embodiment.

[FIG. 4] Similarly, in one embodiment, “atmospheric pressure learning / EG
5 is a flowchart illustrating a continuation of the "R.BACS control routine".

[FIG. 5] In one embodiment, “atmospheric pressure learning / EGR / B”
It is a map used to calculate the operating region of the diesel engine in the process of the "ACS control routine".

FIG. 6 is a time chart showing behaviors of an accelerator lever opening degree, an engine speed, a vehicle speed, a boost pressure, an increase correction amount of a negative pressure command value, and a maximum fuel injection amount at the time of sudden start in one embodiment. .

[Explanation of symbols]

1 ... Diesel engine, 2 ... Fuel injection pump, 10 ...
Turbocharger, 17 ... EVR as negative pressure control valve
V, 22 ... Boocon as a fuel injection amount adjusting mechanism, 23
... Supercharging pressure chamber, 24 ... Negative pressure chamber, 41 ... Water temperature sensor, 42 ...
Lever sensor, 43 ... Rotation speed sensor, 45 ... Vehicle speed sensor (41 to 43, 45 constitute operating state detecting means), 44 ... Intake pressure sensor as supercharging pressure detecting means, 4
7 ... ECU (which constitutes a boost pressure increase rate calculation means and a negative pressure control valve control means).

Claims (1)

[Claims] 1. A diesel engine mounted on a vehicle as a drive source, a supercharger for increasing the pressure of air taken into the diesel engine, a fuel injection pump for pumping fuel to the diesel engine, and a diaphragm. A supercharging pressure chamber and a negative pressure chamber, which are partitioned by the following, and the relationship between the supercharging pressure introduced into the supercharging pressure chamber with the operation of the supercharger and the pressure introduced into the negative pressure chamber. By displacing the diaphragm with a fuel injection amount adjusting mechanism for increasing and correcting the maximum fuel injection amount from the fuel injection pump, and a negative pressure introduced into the negative pressure chamber of the fuel injection amount adjusting mechanism. A negative pressure control valve whose opening is adjusted for control, an operating state detecting means for detecting an operating state of the vehicle and the diesel engine, and a supercharger obtained by the supercharger. A boost pressure detection unit for detecting the boost pressure, and an increase in the boost pressure detected by the boost pressure detection unit when it is determined that the vehicle is starting based on the detection result of the driving state detection unit. A boost pressure increase rate calculating means for calculating the rate, and a negative rate per unit time introduced into the negative pressure chamber according to the boost rate increase rate calculated by the boost pressure increase rate calculating means. A maximum fuel injection amount control device for a diesel engine with a supercharger, comprising: a negative pressure control valve control means for controlling the opening of the negative pressure control valve to adjust the pressure amount.