JP3352625B2 - Internal combustion engine system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an internal combustion engine system provided with an altitude compensator for compensating a fuel supply amount according to altitude, in which an acceleration shock applied to a vehicle when an accelerator pedal is rapidly accelerated is reduced. It is about technology.

[0002]

2. Description of the Related Art In recent years, in a vehicle equipped with a diesel engine, an altitude compensator for correcting a fuel injection amount in accordance with a change in air density due to a difference in altitude in consideration of traveling in a high altitude such as a mountain area. Is adopted. The altitude compensator includes, for example, an altitude injection amount compensator (ACS) and an altitude boost pressure compensator (BACS).
It has been known. The advanced injection amount compensator (ACS) uses a bellows or the like to displace the spill ring in a direction in which the fuel injection amount decreases as the atmospheric pressure decreases. In addition, a highland supercharging pressure compensator (BACS) uses a diaphragm or the like that operates by a differential pressure between a supercharging pressure and a constant negative pressure, and reduces the spill ring as the supercharging pressure decreases due to a decrease in atmospheric pressure. The displacement is made in the direction in which the fuel injection amount decreases.

FIG. 12 is a graph showing the relationship between the engine speed and the fuel injection amount in an engine provided with an altitude compensation device. When the altitude compensator is operated, the maximum fuel injection amount when the accelerator pedal is fully depressed is corrected according to a change in the atmospheric pressure due to a difference in altitude. For this reason, at high altitudes, the maximum fuel injection amount when the accelerator pedal is fully depressed is limited to a smaller amount than when the accelerator pedal is level, and the fuel injection amount is adjusted to match the air density (intake oxygen amount) according to the altitude. Is done. For this reason, generation of black smoke in the exhaust gas when traveling at high altitude is avoided.

[0004] Further, in an automobile engine, an EG for recirculating exhaust gas to an intake system for purifying the exhaust gas is used.
An R device is provided. The EGR device recirculates a part of exhaust gas to an intake system through an EGR passage connecting an exhaust manifold and an intake manifold. EG
As the EGR valve provided for opening and closing the R passage, a negative pressure operated type that opens and closes using a negative pressure, such as a diaphragm type, may be used. The negative pressure operated EGR valve is controlled to open and close by a switching control of a vacuum switching valve (VSV) by an electronic control unit (ECU), and a negative pressure is introduced into a negative pressure chamber of the EGR valve. The valve is opened and closed by opening the negative pressure chamber to atmospheric pressure.

The EGR valve is opened when it is determined from various parameters detected by various sensors provided in the vehicle that the operating state of the engine is in a predetermined EGR ON region. Normally, an EGR ON region is set when a parameter such as an engine speed or an accelerator opening indicates an operating state of the engine at a low or medium load. For this reason, when the accelerator pedal is fully depressed, the parameter of the accelerator opening indicates the operating state under a high load, so that the EGR operation condition is not satisfied and the EGR valve is closed. That is, exhaust gas recirculation is not performed.

[0006]

By the way, the altitude compensating device is operated during the operation of the vehicle, but the spill ring is at a position where the maximum fuel injection amount is not limited when the vehicle is running on level ground. When the accelerator pedal is fully depressed to make a rapid acceleration during flat-land running, the fuel injection amount rapidly increases, for example, from the point (a) to the point (b) of the maximum injection amount as shown in FIG. While the accelerator pedal is fully depressed, it moves along the line of the maximum injection amount that changes according to the engine speed, as shown at point (c).

As shown in FIG. 13, when the accelerator pedal is fully depressed for a rapid acceleration operation, the fuel injection amount sharply increases because the accelerator opening is rapidly opened. As a result, a large acceleration shock for sudden acceleration occurs in the vehicle, and as a result, a front and rear G having a relatively large amplitude as shown in FIG. 13 occurs in the vehicle. There is a problem that the ride quality at the time of sudden acceleration is deteriorated by the back and forth swing of the vehicle body due to the front and rear G.

When the accelerator pedal is suddenly accelerated, the accelerator opening deviates from the EGR-on range in the middle of the operation, and when the EGR on-off determination by the ECU is switched from on to off, the ECU switches to VSV. For EGR
A valve closing command to close the valve is issued. However, E
If the GR valve is a negative pressure operated valve, a valve closing command is issued and EG
Even if atmospheric pressure is introduced into the negative pressure chamber of the R valve, there is a response delay that takes a certain time t until it is completely closed.
Therefore, during the rapid acceleration operation, only a part of the exhaust gas is still recirculated before the EGR valve is completely closed, and only the fuel injection amount is increased. Since it is supplied in excess, there is also a problem that smoke (black smoke) is generated in the exhaust gas as shown in FIG.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to perform a rapid acceleration accelerator operation in an internal combustion engine system having an altitude compensation function of a fuel supply amount. It is an object of the present invention to provide an internal combustion engine system that can reduce an acceleration shock sometimes applied to a vehicle. A second object is to stably perform acceleration shock mitigation control. A third object is to reduce black smoke generated due to a response delay when the EGR valve is closed at the time of rapid acceleration, even when the EGR valve is a negative pressure operated valve in an internal combustion engine system equipped with an EGR device. To make it happen.

[0010]

In order to achieve the first object, according to the first aspect of the present invention, there is provided a first operation state in which a fuel supply amount to be supplied to an engine is altitude-compensated in accordance with atmospheric pressure. An altitude compensator provided so as to be switchable to a second operating state for limiting the fuel supply amount to a smaller value than in the first operating state, and a detection for detecting an accelerator operation at least a possibility of rapid acceleration Means and exhaust of the engine
E for opening and closing the EGR passage connecting the passage and the intake passage
An EGR device having a GR valve, and setting the altitude compensation device to the second operating state when the accelerator operation amount is within a predetermined region that is relatively small, and when the accelerator operation is detected by the detection unit, at a timing capable of fuel supply amount stepwise increased in two steps in the process of rapid acceleration operation as possible to operate in a glass of accelerator operation, before the altitude compensator
Control means for switching from the second operating state to the first operating state after a lapse of a predetermined time from the issuance of the EGR valve closing command .

In order to achieve the second object, according to the second aspect of the present invention, in the first aspect of the present invention, the detecting means detects a sudden acceleration when the accelerator operation amount exceeds a threshold value. Acceleration detection means for detecting a possible acceleration operation, wherein the control means sets the altitude compensation device to a second position after a lapse of a predetermined time from when the accelerator operation amount exceeds the threshold value by the acceleration detection means. From the operating state of the first
The main point is to switch to the operating state of

According to a third aspect of the present invention, in the first or second aspect of the present invention, the detecting means is configured to perform a rapid acceleration operation when the accelerator operation amount exceeds the threshold value. And the control means detects the rapid acceleration operation only when the rapid acceleration operation is detected by the rapid acceleration detection means, and after the lapse of the predetermined time from the detection, The gist of the present invention is to switch the compensator from the second operating state to the first operating state.

[0013] The invention according to claim 4, in the invention of claim 2 or claim 3, prior Symbol acceleration detecting means,
The control means detects that the accelerator operation amount has exceeded the threshold value when the EGR operation condition for opening the EGR valve is not satisfied from a state where the condition has been satisfied.
The gist is to bring the altitude compensating device into the second operating state when the accelerator operation amount satisfies the EGR operating condition.

According to a fifth aspect of the present invention, in order to achieve a third object, in the fourth aspect of the present invention,
The GR valve is a negative pressure operated valve, and the predetermined time is equal to the E.
The time is set to be equal to or longer than the time required for the GR valve to completely close from the valve closing command.

In the invention according to claim 6, in the invention according to any one of claims 1 to 5, the maximum fuel supply amount when the altitude compensation device is in the second operating state is: It is set to a value below the limit value at which the acceleration shock at the time of sudden acceleration does not exceed an allowable amount.

According to the invention described in claim 7, in the invention described in any one of claims 4 to 6, the maximum fuel supply amount when the altitude compensation device is in the second operating state is: When the EGR valve is opened on a flat road, the amount of oxygen in the intake air is adjusted to be equal to or less than a limit value which is not excessive enough to generate black smoke exceeding an allowable amount.

According to the invention described in claim 8, in the invention described in any one of claims 1 to 7, the predetermined time is set within one second. (Operation) According to the first aspect of the invention, when the accelerator operation amount is within the predetermined region that is relatively small, the altitude compensation device is set to the second operation state, and the fuel supply amount is relatively small. Limited. In this state, when the accelerator operation of the rapid acceleration is performed, the accelerator operation is detected by the detecting unit as the accelerator operation at least possibly of the rapid acceleration. Then, at the timing at which the fuel supply amount can be increased stepwise in two stages in the process of the rapid acceleration operation in which the accelerator operation is fully operated by the control means, the altitude compensating device performs the second operation.
Is switched from the operating state to the first operating state. As a result, when a sudden acceleration operation is performed with the accelerator operation being fully operated, the fuel supply amount is first held at the limited maximum supply amount because the altitude compensation device is in the second state, The altitude compensator is moved from the second operating state to the first
Switching to a higher operating state increases the maximum supply at which the restriction has been lifted. That is, the fuel supply amount increases stepwise in two steps. Therefore, the acceleration shock applied to the vehicle during the rapid acceleration operation is reduced as compared with the case where the fuel supply amount suddenly increases.

According to the second aspect of the invention, when the accelerator operation amount exceeds the threshold value, the acceleration operation means detects an accelerator operation (acceleration operation) with a possibility of sudden acceleration. Since the time when the accelerator operation amount exceeds the threshold value is used as a reference for measuring a predetermined time, the fuel supply amount is limited in the process of the rapid acceleration operation regardless of which accelerator operation amount was used for the rapid acceleration operation. It is difficult for the time to be maintained in the state of being varied to occur.

According to the third aspect of the present invention, only when the rapid acceleration detection means detects that the accelerator operation when the accelerator operation amount exceeds the threshold value is due to the rapid acceleration operation, After a predetermined time has passed since the detection,
The control means causes the altitude compensation device to switch from the second operation state to the first operation state.
Operation state. That is, the fuel supply amount is increased stepwise in two stages only when the accelerator operation of sudden acceleration is actually performed.

According to the fourth aspect of the present invention, the altitude compensator is set to the second operation state when the accelerator operation amount satisfies the EGR operation condition that the EGR valve is opened.
When the accelerator operation is performed rapidly and the EGR operation condition is no longer satisfied, the accelerator operation amount is determined to have exceeded the threshold value, and an accelerator operation that may cause rapid acceleration is detected. Is done. Therefore, it is possible to detect an accelerator operation that may cause rapid acceleration by using the determination as to whether or not the EGR operation condition performed for the opening / closing control of the EGR valve is satisfied.

According to the fifth aspect of the present invention, after the EGR operation condition is no longer satisfied from the satisfied condition,
After a lapse of a predetermined time, the altitude compensation device is switched from the second operating state to the first operating state. EG which is a negative pressure operated valve
Even if there is a response delay when the R valve is closed, the fuel supply amount is limited until the EGR valve is completely closed, and the fuel supply amount is released at least after the EGR valve is completely closed.
As a result, even if the sudden acceleration operation is performed, generation of black smoke exceeding the allowable amount is avoided.

According to the sixth aspect of the present invention, the maximum fuel supply amount when the altitude compensation device is in the second operating state is:
Since the acceleration shock at the time of rapid acceleration is set to be equal to or less than the limit value at which the acceleration shock does not exceed the allowable amount, the occurrence of the acceleration shock exceeding the allowable amount at the time of rapid acceleration is avoided.

According to the seventh aspect of the present invention, the maximum fuel supply amount when the altitude compensation device is in the second operating state is:
When the vehicle is running on flat ground, the amount of oxygen in the intake air when the EGR valve is opened is set to a value that is not excessively large enough to generate black smoke exceeding the allowable amount. The generation of black smoke is avoided.

According to the eighth aspect of the present invention, since the predetermined time is set within one second, it is possible to reduce the acceleration shock without deteriorating the acceleration performance of the vehicle.

[0025]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Hereinafter, a first embodiment in which the present invention is embodied in a diesel engine system will be described with reference to FIGS.

FIG. 5 shows a diesel engine system 1 as an internal combustion engine system mounted on an automobile. The diesel engine system 1 includes a diesel engine 2 and a distribution type fuel injection pump 3 for pumping fuel to the engine 2.

The engine body 4 constituting the diesel engine 2 is provided with a number of fuel injection nozzles (not shown) corresponding to the number of cylinders. In the engine body 4,
An intake manifold 5 as an intake passage and an exhaust manifold 6 as an exhaust passage are respectively connected.
The engine 2 is equipped with a turbocharger 7.
The turbocharger 7 includes a turbine 8 that is rotated by exhaust gas from the exhaust manifold 6 and a compressor 9 that is rotated by the torque of the turbine 8. Due to the rotation of the compressor 9, the intake air taken into each combustion chamber of the engine body 4 through the intake passage 10 and the intake manifold 5 is overpressured.

Exhaust gas recirculation (EGR) for recirculating a part of the exhaust gas discharged from the engine body 4 to the intake system
The EGR passage 11 connecting the exhaust manifold 6 and the intake manifold 5 is provided between the exhaust manifold 6 and the intake manifold 5. An EGR valve 12 that opens and closes the EGR passage 11 is provided in the middle of the EGR passage 11. In the present embodiment, E
The GR valve 12 is a diaphragm type negative pressure operated valve.

The EGR valve 12 includes a valve body 12a for opening and closing the EGR passage 11, and a diaphragm 1 connected to the valve body 12a.
2b and a negative pressure chamber 12c partitioned by a diaphragm 12b
And a spring 12d disposed in the negative pressure chamber 12c to urge the diaphragm 12b. EGR valve 1
2 is closed in a state where no negative pressure is introduced into the negative pressure chamber 12c,
The valve is opened when a negative pressure is introduced into the negative pressure chamber 12c. Note that the EGR passage 11 and the EGR valve 12 constitute an EGR device.

The negative pressure chamber 12c of the EGR valve 12 is connected to a first vacuum switching valve (hereinafter, referred to as a first VSV) 14 through a negative pressure passage 13.
A vacuum damper 15 is provided in the middle of the negative pressure passage 13. The first VSV 14 is a three-type solenoid valve having an input port, an output port, and an atmospheric port, and one end of the negative pressure passage 13 is connected to the output port.
An input port of the first VSV 14 is connected to an output port of an electric vacuum regulating valve (hereinafter, EVRV) 17 through a negative pressure passage 16.

The EVRV 17 is an electromagnetic valve whose opening is adjusted by duty control, and its input port is connected to a vacuum pump 19 as a negative pressure source through a negative pressure passage 18.
It is connected to the. The vacuum pump 19 is driven by a rotational force transmitted from a crankshaft (not shown) of the engine body 4. The negative pressure passage 20 connected to the output port of the EVRV 17 is connected to the input port of the pressure sensor 21. The EVRV 17 is duty-controlled based on the detection value detected by the pressure sensor 21 so that the negative pressure of its output port becomes a preset constant negative pressure.

When the first VSV 14 is turned on, the EGR
A negative pressure is introduced into the negative pressure chamber 12c of the valve 12, and the first VSV
When the switch 14 is turned off, the negative pressure chamber 12c of the EGR valve 12 is opened to the atmospheric pressure.

The fuel injection pump 3 is connected to the output shaft of the engine 2. The transmission force input from the output shaft of the engine 2 drives a built-in vane pump (not shown) and a plunger (not shown). ) Reciprocates and discharges fuel in synchronization with the rotation of the output shaft of the engine 2.

The fuel injection pump 3 is provided with a high altitude supercharging pressure compensator (boost altitude conventional stopper) as an altitude compensating device for adjusting the maximum fuel injection amount according to the supercharging pressure. 22 (hereinafter simply referred to as BACS). The BACS 22 has a pressure passage 23 for introducing a supercharging pressure through the intake passage 10.
And a second vacuum switching valve (hereinafter, referred to as a second switching valve)
A negative pressure passage 25 communicating with the output port of the second VSV (referred to as second VSV) 24 is connected. The second VSV 24 is a three-way solenoid valve having an input port, an output port, and an atmospheric port.
Connected to the output port of RV17.

As shown in FIG. 4, the BACS 22 is mounted on the upper part of the governor, and includes a supercharging pressure chamber 22b and a negative pressure chamber 22c which are vertically divided by a diaphragm 22a. A supercharging pressure is introduced into the supercharging pressure chamber 22 b through a pressure passage 23. When the second VSV 24 is switched on or off, a negative pressure or atmospheric pressure is introduced into the negative pressure chamber 22c through the negative pressure passage 25. The diaphragm 22a is in a state of being urged upward by a spring 22d disposed in the negative pressure chamber 22c, and a push rod 27 is fixed at the center thereof in a state of extending downward. Push rod 2
Numeral 7 moves up and down according to the pressure difference between the supercharging pressure chamber 22b and the negative pressure chamber 22c.

The lower portion of the push rod 27 has a tapered portion 2
7a, and the tip of the connecting pin 28 is in contact with the tapered portion 27a. When the push rod 27 moves up and down, the connecting pin 28
Are displaced to the left and right in the figure, and the control arm 29 rotates about the support shaft 29a in accordance with the displacement of the connecting pin 28. Then, as the control arm 29 rotates, the tension lever 30 rotates about the support shaft 30a, and the spill ring 31 is displaced left and right.

The BACS 22 operates when the second VSV 24 is turned on, and stops operating when the second VSV 24 is turned off. In the operation state of the BACS 22, the negative pressure chamber 22
A constant negative pressure is introduced into c. For this reason, the push rod 27 is displaced downward as the supercharging pressure is higher, and the spill ring 31 is displaced.
Is displaced to the right in FIG. On the other hand, as the altitude increases, the atmospheric pressure decreases and the supercharging pressure decreases, so that the push rod 27 is displaced upward, and the spill ring 31 is displaced leftward in FIG. . Therefore, BACS2
In the operating state of 2, the supercharging pressure compensation characteristic and the altitude compensation characteristic are simultaneously obtained for the fuel injection amount.

In the state where the operation of the BACS 22 is stopped,
Since the pressure in the negative pressure chamber 22c is equal to the atmospheric pressure, the amount of downward displacement of the push rod 27 with respect to the supercharging pressure is smaller than that at the time of its operation, and the spill ring 31 is relatively displaced toward the injection amount decreasing side. Therefore, when the operation of the BACS 22 is stopped,
The maximum fuel injection amount when the accelerator pedal is fully depressed is limited to be smaller than that during operation. In this embodiment, the BACS 22 in which the fuel injection amount is altitude-compensated
Corresponds to the first operation state, and the BACS 22 operation stop state in which the fuel injection amount is limited to a small amount corresponds to the second operation state.

The fuel injection pump 3 is provided with a rotation speed sensor 32 for detecting the engine rotation speed and a rotary position sensor 34 for detecting the opening of the accelerator lever 33. The rotary position sensor 34 is composed of a variable resistor and outputs a detection voltage corresponding to the opening of the accelerator lever 33, that is, the amount of depression of the accelerator pedal. Also,
The engine body 4 is provided with a water temperature sensor 35 for detecting a cooling water temperature. An automatic transmission (not shown) has a vehicle speed sensor 36 for detecting the vehicle speed from the rotation of the gear.
Is provided.

The pressure sensor 21, the rotation speed sensor 32, the rotary position sensor 34, the water temperature sensor 35, and the vehicle speed sensor 36 include an electronic control unit (ECU) 3 as control means.
7, each of the sensors 21, 32, 3
The detection signals 4 to 36 are input to the ECU 37. Further, the first VSV 14, the EVRV 17, and the second VSV 24 are electrically connected to the ECU 37, and are controlled based on command signals from the ECU 37, respectively.

A microcomputer 40 built in the ECU 37 has a central processing unit (hereinafter referred to as a CPU) 4.
1, a read-only memory (ROM) 42, a readable / writable memory (RAM) 43, and a counter 44. Note that the rotary position sensor 34 and the microcomputer 40 constitute a detecting unit, an acceleration detecting unit, and a rapid acceleration detecting unit.

The ROM 42 is used to determine whether or not the operating state determined by various parameters detected from the various sensors 32 and 34 and the like belongs to a predetermined "EGR on area" in which exhaust gas recirculation is to be performed. A map is stored. For example, the “EGR-on region” is set when the engine is in a low-medium-speed operation state, and deviates from the “EGR-on region” during a high-speed operation (for example, when the accelerator opening is large). Therefore, during a rapid acceleration in which the accelerator pedal is fully depressed from the operating state in the EGR-on region, the vehicle deviates from the EGR-on region when the accelerator opening exceeds a certain value.

The CPU 41 determines whether the operating state of the engine is in the EGR ON region based on various parameters detected by the various sensors 32, 34 and the like.
On-off determination (hereinafter, referred to as EGR determination) is performed. C
When the EGR determination is “ON”, the PU 41 outputs the first VS
V14 is turned on to open the EGR valve 12, and the first VSV 14 is turned off and the E
The GR valve 12 is closed.

The BACS 22 is activated when the second VSV 24 is turned on by the CPU 41 when the engine is started. In the present embodiment, the operation of the BACS 22 is stopped when the operation state of the engine is in the EGR ON region for the control for reducing the acceleration shock and the black smoke during the rapid acceleration. The ROM 42 stores program data shown in FIG.

FIG. 3 shows the relationship between the engine speed and the fuel injection amount on flat ground (low altitude). When the altitude compensating device (BACS) 22 is in the operating state (first operating state), when the accelerator pedal is fully depressed because there is almost no decrease in the fuel injection amount due to altitude compensation because the ground is flat. Takes a value on a line indicated by a solid line in FIG. 3, which is almost the upper limit value. On the other hand, when the altitude compensator (BACS) 22 is in the operation stop state (second operation state), the maximum injection amount Slimit
Takes a value on a line shown by a chain line in FIG. 3 which is limited to a small value with respect to the maximum injection amount Smax.

If the maximum injection amount Slimit when the operation of the BACS 22 is stopped is too large to generate black smoke exceeding the allowable amount with respect to the oxygen amount in the intake air when the EGR valve 12 is opened during running on level ground. And a limit value that does not cause an acceleration shock to exceed an allowable amount during sudden acceleration. The adaptation of the maximum injection amount Slimit is performed, for example, by adjusting the setting of the elastic force of the spring 22d.

The counter 44 is used for measuring time. In the present embodiment, when the EGR determination is switched from “ON” to “OFF”, the CPU 41
A command to close the GR valve 12 (that is, a command to turn off the first VSV 14) is issued. At this time, when the EGR determination is changed from “on” to “off” because the accelerator pedal is depressed vigorously to accelerate rapidly, a predetermined time T (eg, 0 in the present embodiment) from the command to close the EGR valve 12. .5
Second), the operation command of the BACS 22 (that is, the second V
SV24 ON command). The counter 44 is used to measure a predetermined time T at this time.

When the operation command of the BACS 22 is delayed by a predetermined time T during rapid acceleration, the maximum fuel injection amount is switched from Slimit to Smax in two stages during the rapid acceleration. For this reason, when the accelerator pedal is fully depressed for rapid acceleration, the fuel injection amount is temporarily reduced to the maximum injection amount Slimit and then gradually increased to the maximum injection amount Smax in two steps. How to increase. In the present embodiment, by increasing the fuel injection amount at the time of rapid acceleration in two stages, the acceleration shock is reduced and the response delay (operation delay) at the time of closing the EGR valve 12, which is the negative pressure actuated valve, is reduced. The aim is to reduce black smoke generated due to this.

The reason why the predetermined time T is set to 0.5 second is that the EGR valve 12, which is a negative pressure actuated valve, is about 0.2 to
This is because the BACS 22 is switched to the operating state after the valve is completely closed in about 0.3 seconds and after the exhaust gas in the intake further decreases to some extent and the oxygen concentration thereof becomes almost stable. Further, in order to reduce the acceleration shock at the time of sudden acceleration, it is sufficient that a time difference between the two commands is secured by about 0.2 to 0.3 seconds, and the predetermined time T is set to 0.5 seconds. It is enough to keep the acceleration shock mitigation. The predetermined time T is not limited to 0.5 seconds, and an appropriate time can be set depending on the purpose and matching with the vehicle. If the predetermined time T is too long, the acceleration performance will be reduced. Therefore, it is preferable to set the predetermined time T within 1 second in order to secure a certain level of acceleration performance. When the EGR determination is switched from "on" to "off" for a reason other than sudden acceleration, the EGR
The valve opening command of the valve 12 and the operation command of the BACS 22 are performed simultaneously.

The determination that the accelerator pedal is depressed by "sudden acceleration" is made by the rotary position sensor 3
This is done by observing the change over time of the detection voltage input from No. 4. That is, the accelerator opening ACCP detected by the rotary position sensor 34 is stored in the RAM 43 each time, and a difference between the previous and current values of the accelerator opening ACCP is obtained. I try to judge.

Next, program data for measures at the time of sudden acceleration will be described with reference to the flowchart shown in FIG. This program is started after the operation of the altitude compensator (BACS) 22 is started when the engine is started, and is executed, for example, every several tens of milliseconds during the operation of the engine.

First, in step 10, each sensor 3
2, 34, etc., the engine speed NE,
The accelerator opening ACCP and the like are read. In step 20, it is determined from the read parameters NE, ACCP and the like, using a map, whether or not the operation state at that time is in the EGR ON region. In step 30, it is determined whether or not the EGR determination is a switch from “off” to “on”. The CPU 41 has an EGR flag to remember whether the previous EGR determination is ON or OFF. The CPU 41 has a flag value of the EGR flag, and an EGR determination result obtained by using a map from various parameters this time. This determination is made by comparing

In step 40, if the EGR determination is switched from "OFF" to "ON", a valve opening command for opening the EGR valve 12 is issued. That is, the first
Command to turn on the VSV 14 is issued. Next Step 5
At 0, a stop command for stopping the operation of the altitude compensator (BACS) 22 is issued. That is, the second VS
A command to turn off V24 is issued. Therefore, when the operating state is switched to the EGR ON region, the operation of the BACS 22 is stopped almost simultaneously with the opening of the EGR valve 12. Therefore, when the EGR valve 12 is opened and the exhaust gas recirculation (EGR) is executed, the fuel injection amount is limited to be smaller than that during the operation by stopping the operation of the altitude compensator (BACS) 22. become. If the EGR determination in step 30 is not switching from “off” to “on” (that is, if the previous EGR determination is also “on”), the EGR valve 12 is already in the open state, Since the valve command has already been issued, the routine ends.

On the other hand, at step 20, the operating state is E
If not in the GR-on area, at step 60, EG
It is determined whether or not the R determination is a switch from “on” to “off”. That is, the CPU 41 makes this determination by comparing the flag value of the EGR flag with the present EGR determination result. When the EGR determination is switched from “on” to “off”, in step 70, a command to close the EGR valve 12 is issued. That is, a command to turn off the first VSV 14 is issued.

In step 80, the switching of the EGR determination from "on" to "off" corresponds to "sudden acceleration".
It is determined whether or not it is due to. That is, the accelerator opening ACC detected by the rotary position sensor 34
Looking at the difference between the previous value and the current value of P, if the difference is equal to or larger than a predetermined set value, it is determined that "sudden acceleration". The CPU 41 reads out and uses the previous accelerator opening degree ACCP stored in a predetermined storage area of the RAM 43.

If it is "sudden acceleration", in step 90, the counter 44 is reset to start timing. Therefore, the counter 44 counts a count value corresponding to the elapsed time after the command to close the EGR valve 12 is issued. At the start of counting of the counter T44, a timing flag is set in order to remember that counting is in progress.

If the EGR determination in step 60 is not a switch from "ON" to "OFF" (the previous EG
If the R determination is also “OFF”, in step 100, it is determined whether or not the counter 44 is counting a clock from the flag value of the clock flag. If the timekeeping flag is set and timekeeping is in progress, in step 110, the counter 4
4 is incremented. If the timekeeping flag is reset and the timekeeping is not in progress, the routine is terminated because the EGR valve 12 is already closed or a command to close the EGR valve 12 has already been issued.

In step 120, the EGR valve 12
A predetermined time T (0.5 seconds in this embodiment) from the valve closing command
It is determined whether or not has elapsed. That is, it is determined whether or not the count value of the counter 44 has reached the count value corresponding to the predetermined time T. If the predetermined time T has not elapsed, the routine ends. Then, when the count value of the counter 44 reaches the count value corresponding to the predetermined time T, in step 130, the counting by the counter 44 is stopped, and
Reset the timing flag. Then, in step 140, an operation command for operating the altitude compensation device (BACS) 22 is issued. That is, a command to turn on the second VSV 24 is issued. Therefore, when the switching of the EGR determination from “on” to “off” is due to “sudden acceleration”, a predetermined time T (0.5) from the command to close the EGR valve 12 is issued.
Seconds), the BACS 22 will be activated.

Next, the operation of the engine system 1 will be described. During operation of the engine, the altitude compensator (BACS) 22 is operated in principle. For this reason, when the altitude increases and the supercharging pressure decreases relative to the amount of depression of the accelerator pedal, the spill ring 31 is displaced to the side where the injection amount decreases, so that as the altitude increases, the maximum fuel injection amount decreases. Can be suppressed. However, in the present embodiment, when the operation state of the engine is in the EGR ON region, the operation of the BACS 22 is temporarily stopped. For this reason, when exhaust gas recirculation (EGR) is being performed by opening the EGR valve 12, the operation of the BACS 22 is stopped, and the negative pressure chamber 22c is stopped.
Is released to the atmospheric pressure, and the spill ring 31 is displaced toward the injection amount decreasing side. Therefore, even on level ground (low altitude), E
During GR execution, the injection amount is limited to the maximum injection amount Slimit indicated by a chain line in FIG.

Then, as shown in FIGS. 1 and 3, the EGR
When the accelerator pedal is fully depressed during execution and the vehicle is rapidly accelerated (states (1) to (3)), the accelerator opening ACCP increases sharply, but even if the accelerator pedal is fully depressed. , The injection amount is limited to Slimit. During the accelerator pedal depression process, the accelerator opening ACCP
Is out of the EGR ON region and the EGR determination is switched from “ON” to “OFF” (state (2)), the EGR valve 1
2, a command to turn off the first VSV 14 is issued. Then, a predetermined time T (0.
After 5 seconds), the altitude compensator (BACS) 22 is activated. That is, the BACS 22 is changed from the second operation state in which the BACS 22 is stopped to the first operation state in which
Is switched to the operation state (state of (4)).

Before the predetermined time T (0.5 seconds) elapses, the fuel injection amount is limited to the maximum injection amount Slimit and temporarily stays in that state, and the BACS 22 is switched to the operating state (first operating state). In other words, the fuel injection amount increases from the maximum injection amount Slimit to the maximum injection amount Smax (state (5)). That is, during rapid acceleration, the fuel injection amount increases in two stages. While the accelerator pedal is fully depressed, the maximum injection amount Smax changes along with the engine speed along the solid line shown in FIG. 3 (state (6)).

As described above, even if the accelerator pedal is fully depressed due to rapid acceleration during the execution of EGR, the fuel injection amount temporarily stops at the maximum injection amount Slimit and then reaches the maximum injection amount Smax as shown in FIG. It will increase in two stages. For this reason, the acceleration shock acting on the vehicle is reduced. As a result, as shown in FIG. 1, the initial acceleration impact is suppressed to a small value, so that the front-back G (the front-back direction shaking acceleration) applied to the vehicle for a while after that as a return is suppressed.

Even if it takes a certain time (for example, about 0.2 to 0.3 seconds) for the EGR valve 12 to be completely closed because the EGR valve 12 is a negative pressure operated valve, the EGR valve 12 is closed. Until the oxygen concentration in the intake air is stabilized to some extent after the valve, the injected fuel is limited to the maximum injection amount Slimit. Therefore, since it is possible to avoid an excessive fuel supply state with respect to the oxygen amount in the intake air, the amount of black smoke (smoke) generated even if the vehicle is suddenly accelerated from the operating state during the execution of EGR as shown in FIG. It can be kept within the allowable amount. If the acceleration is not rapid, the operation of the BACS 22 will be stopped almost simultaneously with the command to open the EGR valve 12, but since the fuel supply is not in an excessive fuel supply state, no black smoke is generated. As described in detail above, according to this embodiment, the following effects can be obtained.

(1) The operation of the BACS 22 is stopped during the execution of the EGR, and when the BACS 22 is rapidly accelerated, after a predetermined time T (0.5 second) elapses from the command to close the EGR valve 12, the BACS 22 is stopped.
By operating the fuel injection valve 22, the fuel injection amount at the time of sudden acceleration is increased in two stages. Therefore, even if the EGR valve 12 is a negative pressure actuated valve that has a response delay when the EGR valve 12 is closed, the black smoke generated during the sudden acceleration can be improved by alleviating the acceleration shock during the rapid acceleration. The generation amount of (smoke) can be suppressed within an allowable amount.

(2) When the EGR determination is switched from on to off, it is considered that the accelerator operation is a possibility of rapid acceleration, and the rapid acceleration is determined only at that time. Can be relatively reduced.

(3) Since the time when the EGR determination is switched from ON to OFF and the command to close the EGR valve 12 is issued is used as a reference for starting the predetermined time, the rapid acceleration operation starts at any accelerator opening. Regardless of whether or not the fuel injection amount has been set, the time during which the fuel injection amount is limited to the maximum injection amount Slimit can be made substantially constant with little variation. Further, the EGR valve 12
Since the time when the valve closing command is issued is used as a reference for starting the timing of the predetermined time, by setting the predetermined time in accordance with the time required for the EGR valve 12 to close,
Black smoke during sudden acceleration operation can be reliably suppressed to within an allowable amount with a minimum required time.

(4) Since the predetermined time T is set to the time (0.5 seconds) required until the EGR valve 12 is completely closed and the oxygen concentration in the intake air is stabilized to some extent, the amount of generated black smoke is reduced. It can be reduced more effectively. The predetermined time T is 1
Since it is extremely short, less than a second, there is little concern that acceleration performance will be impaired.

(5) If the operation of the BACS 22 is stopped, the negative pressure chamber 22c is opened to the atmospheric pressure, and the maximum injection amount is originally limited to a small value.
Since the CS22 is used, it can be dealt with only by changing the program data for controlling the BACS22. That is,
BACS structural improvement and VS to control it
There is no need to provide new components such as V.

(6) Since the fuel injection amount is increased in two stages, wasteful use of fuel during rapid acceleration is avoided, which contributes to improvement in fuel efficiency. (Second Embodiment) Next, a second embodiment of the present invention will be described with reference to FIGS.

This embodiment is an example in which the engine 2 is not provided with a turbocharger, and the fuel injection pump 3 is provided with an advanced injection amount compensator (ACS). Other configurations provided in the diesel engine system 1 such as the EGR device are the same as those in the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted, and only different portions will be described.

As shown in FIG. 6, an advanced injection amount compensator (ACS) 50 as an altitude compensator is
Is provided above the governor, and the ACS50 has a second VSV
A negative pressure passage 52 connected to the output port 51 is connected. The second VSV 51 is a three-type solenoid valve having an input port, an output port, and an atmospheric pressure port. The input port is connected to the output port of the EVRV 17 through the negative pressure passage 53. That is, it is different from the conventional ACS in that a negative pressure can be introduced into the ACS 50.

As shown in FIG. 8, the ACS 50 is
A bellows 50b is provided at 0a, and a push rod 54 is fixed to the bellows 50b so as to extend downward.
A negative pressure or an atmospheric pressure is introduced into the atmosphere chamber 50a through the pressure passage 52 by switching the second VSV 51 on or off. The push rod 54 is in a state of being urged upward by a spring 50c provided in the atmosphere chamber 50a.

The lower portion of the push rod 54 has a tapered portion 5
4a is formed, and the tip of the connecting pin 28 is in contact with the tapered portion 54a. When the push rod 54 moves up and down, the connecting pin 28
8 is displaced right and left in FIG. 8, and the control arm 29 rotates about the support shaft 29a in accordance with the displacement of the connecting pin 28. When the control arm 29 rotates, the tension lever 30
Are rotated about the support shaft 30a, and the spill ring 31 is displaced left and right.

When the second VSV 51 is turned off, the ACS 50 is in an operation state in which the fuel injection amount is highly compensated, and when the second VSV 51 is turned on, the ACS 50 is in an operation stop state. In the operation state of the ACS 50, the atmosphere chamber 50a is opened to the atmospheric pressure. As the altitude increases and the atmospheric pressure decreases, the push rod 54 is displaced downward, and the spill ring 3
1 is displaced leftward in FIG. 8, that is, toward the injection amount decreasing side. On the other hand, on a flat terrain, the atmospheric pressure is higher than on a highland, so the push rod 54 is displaced upward, and
1 is located to the right in FIG. 8, that is, on the injection amount increasing side. Therefore, in the operation state of the ACS 50, the altitude compensation characteristic is obtained for the fuel injection amount.

When the operation of the ACS 50 is stopped, a constant negative pressure is forcibly introduced into the atmosphere chamber 50a. Therefore, the push rod 54 is displaced downward regardless of the altitude,
The spill ring 31 is displaced to the left in FIG. In the ACS 50, the maximum injection amount Slimit when the operation is stopped does not become excessive enough to generate black smoke exceeding an allowable amount with respect to the oxygen amount in the intake air during flat ground traveling when the EGR valve 12 is opened, and It is adjusted to a value below a limit value that is not excessive so as to generate an acceleration shock exceeding an allowable amount at the time of rapid acceleration. Maximum injection amount Slimi
The adaptation of t is performed by, for example, adjusting the setting of the elastic force of the spring 50c or adjusting the set value of the constant negative pressure. The operation state of the ACS 50 corresponds to a first operation state, and the operation stop state of the ACS 50 corresponds to a second operation state.

The electrical configuration of the diesel engine system 1 is the same as that of the first embodiment.
As the ACS 22 is replaced with the ACS 50, a second VSV 51 for controlling the operation of the ACS 50
There is no particular difference from the first embodiment except that is connected to the ECU 37. However, BACS is the second VSV2
4 is turned on, but the ACS 50 is turned on when the second VSV 51 is turned on.

The ACS 50 is used when the engine is started.
This is activated by turning off the second VSV 51 by 37. However, while the engine is running, each sensor 3
Various parameters NE, AC detected by 2, 34, etc.
When the operating state at that time is in the EGR ON region based on the CP or the like, the second VSV 51 is turned off and the ACS 50 is turned off.
Operation is stopped.

Then, as in the first embodiment, RO
The operation of the EGR valve 12 and the ACS 50 is controlled based on the program data for countermeasures at the time of sudden acceleration shown in FIG. As shown in the timing chart of FIG. 7, when the accelerator pedal is fully depressed, for example, and the vehicle is rapidly accelerated during the EGR, the EGR determination is switched from “on” to “off” with an increase in the accelerator opening ACCP. However, sudden acceleration is determined in the rapid acceleration determination. Therefore, first, a command to close the EGR valve 12 is issued, and after a lapse of a predetermined time T (0.5 seconds in this embodiment) from the time of the valve closing command, the second VSV 51 is switched from on to off, and the altitude compensation device ( ACS) 50 is activated.

Therefore, according to this embodiment, FIG.
As shown in FIG. 7, when the accelerator pedal is fully depressed to accelerate suddenly during execution of EGR, the fuel injection amount is first limited to the maximum injection amount Slimit (states (1) to (3)). . Then, the fuel injection amount remains at the maximum injection amount Slimit, and when the predetermined time T (0.5 seconds) elapses, the altitude compensation device (AC
When S) 50 is operated, the maximum injection amount Slimit is increased to the maximum injection amount Smax (the states of (4) and (5)). As described above, the amount of fuel injection increases stepwise in two stages during rapid acceleration, so that the acceleration shock acting on the vehicle can be suppressed to a small level. As a result, as shown in FIG. 7, since the initial acceleration impact is suppressed to a small value, the front-rear G (the front-rear direction shaking acceleration) applied to the vehicle for a while thereafter as the swingback is suppressed to a small value.

Even if it takes a certain period of time (for example, about 0.2 to 0.3 seconds) to completely close the EGR valve 12 because the EGR valve 12 is a negative pressure operated valve, the EGR valve 12 is closed. Until the oxygen concentration in the intake air is stabilized to some extent after the valve, the injected fuel is limited to the maximum injection amount Slimit. Therefore, as shown in FIG. 7, even if the vehicle is suddenly accelerated from the operating state during the execution of the EGR, the amount of generated black smoke (smoke) can be suppressed within an allowable amount. Therefore, according to this embodiment in which the ACS 50 is provided as an altitude compensating device, (1) to (1) described in the first embodiment are used.
The same effects as (4) and (6) can be obtained.

(Third Embodiment) Next, a third embodiment of the present invention will be described with reference to FIGS. This embodiment is an example in which EGR determination is not used in control for measures at the time of sudden acceleration. BACS2 of the first embodiment
A diesel engine system 1 comprising the second
The present invention can be applied to any configuration of the diesel engine system 1 including the ACS 50 of the embodiment. Less than,
This embodiment will be described focusing on the contents of program data having a different configuration from the above embodiments. For convenience of explanation, the engine system 1 of the first embodiment including the BACS 22 as an altitude compensation device will be described as an example.

FIG. 9 shows the program data stored in the ROM 42 for the measures at the time of sudden acceleration. This program is executed, for example, every several tens of milliseconds during the operation of the engine. In the present embodiment, the state of rapid acceleration is detected by the same method as in the first and second embodiments.
When the accelerator opening ACCP is less than the set value K, the operation of the high altitude supercharging pressure compensator (BACS) 22 as an altitude compensator is stopped, and when a sudden acceleration is detected, a predetermined time is determined from the time of the detection. After the elapse of the time T, the BACS 22 is operated. When the predetermined time T is counted, the counter 4
4 is used, and the fact that the counter 44 is counting the time is determined from the flag value of the timing flag provided in the CPU 41.

First, at step 210, each sensor 3
The accelerator opening ACCP is read based on the detection signal of No. 2.
In step 220, it is determined whether or not the counter 44 is counting time. If the timekeeping flag is reset and the timekeeping is not being performed, the process proceeds to the next step 230. When the timekeeping flag is set and the timekeeping is in progress, the process proceeds to step 260.

In step 230, it is determined whether or not the vehicle is suddenly accelerated. That is, it is determined whether or not the accelerator pedal is being rapidly accelerated. Accelerator opening AC
When the difference between the previous and current detection values of the CP is equal to or greater than a predetermined set value, it is determined that “sudden acceleration”. For example, a set value is set so that rapid acceleration is performed when the accelerator opening increases by 20% or more within 0.5 seconds.

When "sudden acceleration" is detected, at step 240, the counter 44 is reset to start timing. For this reason, the counter 44 counts a count value corresponding to the elapsed time after the rapid acceleration is detected. At the start of time counting by the counter 44, a time counting flag is set to remember that time counting is in progress.

In step 250, it is determined whether a predetermined time T has elapsed. That is, it is determined whether or not the count value of the counter 44 has reached the count value corresponding to the predetermined time T. If the predetermined time T has not elapsed, the routine ends. In this case, in the next process, step 22
Since it is determined that the timer is counting at 0, the process of incrementing the counter 44 is performed at step 260. Then, the count value of the counter 44 reaches a count value corresponding to the predetermined time T.
If it is determined that has elapsed, the process proceeds to step 270,
The counting by the counter 44 is stopped, and the counting flag is reset.

At step 280, an operation command for operating the altitude compensator (BACS) 22 is issued. That is, a command to turn on the second VSV 24 is issued. For this reason, when “sudden acceleration” is detected, the BACS 22 is operated after a lapse of a predetermined time T from the time of detection. It should be noted that, during the predetermined time T, regardless of where the accelerator opening ACCP is below the set value K, even if rapid acceleration is detected, during a rapid acceleration operation in which the accelerator pedal is fully depressed, the fuel injection amount is as shown in FIG. Is set to a value (for example, 0.5 seconds) that can increase stepwise in two steps. In this embodiment, the negative pressure operated valve EG
After the R valve 12 is completely closed, and after the exhaust gas during intake further decreases to some extent and the oxygen concentration thereof becomes almost stable, the predetermined time T is set so that the BACS 22 switches from the operation stop state to the operation state. ing. Further, the predetermined time T set in this manner is a sufficient time from the viewpoint of alleviating the acceleration shock.

On the other hand, if no rapid acceleration is detected in step 230, it is determined in step 290 whether or not the accelerator opening ACCP is less than the set value K. When the accelerator opening ACCP is smaller than the set value K, the process proceeds to step 300, and when the accelerator opening ACCP is equal to or larger than the set value K, the process proceeds to step 280. Therefore, when the accelerator opening ACCP is equal to or larger than the set value K, the altitude compensator (BACS) 22 is activated. Here, the set value K is such that when the fuel injection amount reaches the maximum injection amount Smax at a time when the vehicle is suddenly accelerated, black smoke is generated exceeding an allowable amount or an acceleration shock is generated in the vehicle. This is a value set slightly higher than the limit value of the accelerator opening degree. For this reason, when the accelerator opening is equal to or larger than the set value K, even if the vehicle is rapidly accelerated, if the black smoke does not exceed the allowable amount, the acceleration shock does not exceed the allowable value.

In step 300, a stop command for stopping the operation of the altitude compensator (BACS) 22 is issued. That is, a command to turn off the second VSV 24 is issued. Therefore, when the accelerator opening ACCP is less than the set value K, the operation of the BACS 22 is stopped. Therefore, when the accelerator opening ACCP is less than the set value K, the maximum fuel injection amount is limited to the maximum injection amount Slimit.

As described above, according to the present embodiment, the operation of the BACS 22 is performed in a state where the accelerator opening ACCP is within a region less than the set value K at which black smoke and acceleration shock may occur when suddenly accelerated. Is stopped.

As shown in FIGS. 10 and 11, even when the accelerator pedal is fully depressed and the accelerator is fully accelerated in a state where the accelerator opening ACCP is less than the set value K (states (1) to (2)). First, the fuel injection amount is limited to the maximum injection amount Slimit. After a sudden acceleration is detected, a predetermined time T
(For example, 0.5 seconds), the altitude compensation device (BAC
S) 22 is operated (state of (3)). When the BACS 22 switches from the operation stop state (second operation state) to the operation state (first operation state), the restriction that the fuel injection amount is limited to the maximum injection amount Slimit is released, and the fuel injection amount is reduced. It increases from the maximum injection amount Slimit to the maximum injection amount Smax (the states of (3) and (4)). While the accelerator pedal is fully depressed, the fuel injection amount takes a value Smax on the solid line that changes as shown in FIG. 3 as the engine speed increases (state (5)).

As described above, at the time of rapid acceleration, the fuel injection amount increases stepwise in two stages, so that the acceleration shock applied to the vehicle is suppressed to a small value. As shown in FIG. Swing acceleration) can be kept small. Further, even if there is a response delay until the EGR valve 12 is a negative pressure operated valve and is completely closed, the predetermined time T
By the setting of the above, at least the fuel injection amount is limited to the maximum injection amount Slimit until the oxygen concentration in the intake air is stabilized to some extent after the EGR valve 12 is closed. Therefore, FIG.
As shown in the figure, the amount of black smoke (smoke) is suppressed to within an allowable amount even during rapid acceleration.

Therefore, according to the present embodiment, too, the first
The effects (1), (4), (5), and (6) described in the embodiment can be similarly obtained. When applied to the engine system 1 in the second embodiment, the effects (1), (4), and (6) described in the second embodiment can be obtained similarly.

The embodiment is not limited to the above, but may be modified as follows. In the first and second embodiments, the sudden acceleration determination (S80) may be omitted. In other words, by switching the EGR determination from ON to OFF, it may be detected that the accelerator operation exceeds the threshold value and the accelerator operation with the possibility of rapid acceleration is performed. According to this configuration, even when the EGR operation condition is not satisfied due to a factor other than the accelerator opening, the altitude compensator 22 (50) is switched from the second operation state to the first operation state with a delay of the predetermined time T. Although the switching is performed, at least the fuel injection amount can be increased stepwise in two steps when the rapid acceleration operation is performed. Therefore, the same effects as those of the first and second embodiments can be obtained, and the control content can be simplified by omitting the sudden acceleration determination.

The upper limit of the predetermined range of the accelerator opening when the altitude compensator is brought into the second operating state, and the accelerator opening for detecting that the accelerator operation is a possibility of sudden acceleration. The thresholds need not necessarily be the same. For example, the altitude compensator may be switched from the first operating state to the second operating state at a stage higher than the threshold in the process of decreasing the accelerator opening.

In the second embodiment, the threshold value of the accelerator opening is set, and when the accelerator opening exceeds the threshold, a sudden acceleration determination is made. The altitude compensator may be switched from the second operating state to the first operating state after a lapse of time. According to this configuration, it is possible to reduce the variation in the time during which the fuel injection amount is limited to Slimit regardless of the accelerator opening at the time when the rapid acceleration operation is started. Can be stably controlled.

The EGR valve is not limited to a negative pressure operated valve. For example, an EGR valve composed of an electromagnetic valve that is opened and closed by being demagnetized based on a command signal from the ECU, and an EGR valve that is opened and closed by a motor whose rotation is controlled based on a command signal from the ECU In the above, the altitude compensation device may be operated with a delay of a predetermined time from the valve closing command. Even in these configurations, even when the response delay at the time of closing the EGR valve does not pose a problem at the time of sudden acceleration in flat-land running, the acceleration shock at the time of sudden acceleration can be suppressed to be small and the riding comfort can be improved.

In the third embodiment, the set value K is set as a threshold value, and when the accelerator opening ACCP exceeds the set value K is detected as an accelerator operation with the possibility of sudden acceleration, After a predetermined time T has passed since the time point ACCP passed the set value K, the altitude
It is also possible to adopt a configuration in which the operating state is switched to the first operating state.

In the third embodiment, the set value K is used as a threshold value, and when the accelerator opening ACCP exceeds the set value K, it is determined whether or not it is due to a sudden acceleration operation. The altitude compensator is switched from the second operating state to the first operating state after a lapse of a predetermined time T from the point in time when the accelerator opening ACCP exceeds the set value K only when it is determined that this is the case. You can also.

In the third embodiment, a predetermined time T to wait for the timing of switching the altitude compensator 22 (50) from the second operation state to the first operation state from the time of detecting the rapid acceleration is determined by the detection of the rapid acceleration. It may be configured to calculate according to the value of the accelerator opening at the time. According to this configuration, the holding time for limiting the maximum fuel supply amount during the rapid acceleration operation can be made substantially constant regardless of the accelerator opening at which the rapid acceleration is detected. Of course, when sudden acceleration is detected, the time when the EGR determination is switched from on to off may be used as a reference for measuring the predetermined time T. In this case, EG
In a configuration in which the R valve 12 is a negative pressure operated valve, the amount of black smoke generated due to a response delay when the valve is closed can be reduced more effectively.

A sensor capable of detecting the degree of opening of the EGR valve 12 is provided, and after confirming from the detection signal of the sensor that the EGR valve 12 has been closed, the operation of the altitude compensator 22 (50) is stopped. It may be. In this case, the time when it is confirmed that the EGR valve 12 is closed based on the detection signal of the sensor is the time when the predetermined time has elapsed. of course,
After closing the EGR valve 12 and waiting for the time necessary for the oxygen concentration in the intake air to stabilize, the altitude compensator 22 (50)
Can also be activated. According to this configuration, even if the response delay varies until the EGR valve 12 is completely closed, it is possible to increase the fuel to the maximum injection amount Smax after the EGR valve 12 is securely closed and the intake air is always stabilized. it can. Therefore, the effect of reducing black smoke can be further enhanced.

The timing at which the altitude compensator 22 (50) is switched from the first operating state to the second operating state is E
The present invention is not limited to the case where the GR determination is switched from “off” to “on”. It is sufficient that the altitude compensator 22 (50) has been switched to at least the second operating state by the time the EGR valve 12 is closed.

The predetermined time from when the EGR valve 12 is closed to when the altitude compensator 22 (50) is switched from the second operating state to the first operating state can be changed as appropriate. For example, the predetermined time can be set so that the altitude compensator 22 (50) switches from the second operating state to the first operating state almost at the same time when the EGR valve 12 is completely closed. If the amount of generated black smoke can be suppressed to the allowable amount or less, the altitude compensator 22 (50) switches from the second operating state to the first operating state in a half-open state before the EGR valve 12 is completely closed. The predetermined time can be set so as to switch to the operation state of.

The predetermined time T can be set for the purpose of only relaxing the acceleration shock during rapid acceleration. For example, a solenoid valve that does not cause black smoke due to valve closing delay
In the configuration used for the GR valve, the shortest possible time within a range in which the acceleration shock can be reduced can be set as the predetermined time T (for example, 0.2 to 0.3 seconds). According to this configuration, the acceleration shock can be reduced and the riding comfort can be improved without significantly deteriorating the acceleration performance during rapid acceleration.

The present invention is not limited to the distribution type fuel injection pump, but can be implemented in an internal combustion engine system provided with a fuel injection device that mechanically adjusts the fuel injection amount. The technical ideas (inventions) grasped from the above embodiments and not described in the claims are described below together with their effects.

(1) The fuel supply amount according to any one of claims 1 to 8, wherein the fuel supply amount is set in two stages in a rapid acceleration operation in which at least the accelerator operation is fully operated. It is set so that it can be increased. According to this configuration, the same effect as the invention described in any one of claims 1 to 8 can be obtained.

(2) In claim 1, when the detecting means detects the accelerator operation which has at least a possibility of sudden acceleration, the control means controls the altitude compensating device after a lapse of a predetermined time from the detection. Switching from the second operating state to the first operating state. According to this configuration, the same effect as the first aspect can be obtained.

(3) In any one of claims 2 to 8, the accelerator operation with a possibility of sudden acceleration is an acceleration operation. According to this configuration, claims 2 to 8 are provided.
The same effect as the invention described in any one of the above is obtained.

(4) In any one of claims 3 to 8, the rapid acceleration detecting means detects rapid acceleration when a time change of the accelerator opening exceeds a set value.
According to this configuration, the sudden acceleration operation can be detected relatively easily from the detected value of the accelerator opening, and the same effect as any one of claims 3 to 8 can be obtained.

(5) In the fifth aspect, the predetermined time is a length obtained by adding the stabilization time required until the exhaust gas decreases and the oxygen concentration in the intake air becomes stable after the closing of the EGR valve to the required time. That's it. According to this configuration, since the amount of oxygen supplied to the intake air is sufficiently increased and stabilized to some extent, the fuel supply amount is increased, so that the effect of suppressing black smoke can be further enhanced.

(6) The apparatus according to any one of claims 1 to 8, further comprising detecting means for detecting that the EGR valve has been closed, wherein the control means includes a detecting means for detecting that the EGR valve is closed.
The altitude compensator is switched to the first operation state when the time when the valve is closed is detected as the elapse of the predetermined time. According to this configuration, even if the response delay time when the EGR valve closes varies, the altitude compensator can be switched to the first operation state after the EGR valve is surely closed.
For this reason, it is possible to reliably prevent an excess fuel state, and to surely prevent the amount of generated black smoke from exceeding an allowable amount.

(7) The altitude compensating device according to any one of claims 1 to 8, wherein the altitude compensating device is a high altitude supercharging pressure compensating device (B
ACS). According to this configuration, almost no structural improvement of the highland supercharging pressure compensator is required, and it can be dealt with only by changing the program data for controlling its operation.

(8) The altitude compensating device according to any one of claims 1 to 8, wherein the altitude compensating device is an altitude injection amount compensating device (A
CS). According to this configuration, claim 1 to claim 8
The same effects as those of the invention described in any one of the above items can be obtained, and the present invention can be applied to an internal combustion engine system having no turbocharger.

[0114]

As described above in detail, according to the first aspect of the invention, the fuel injection amount is limited by setting the altitude compensator to the second operating state in a predetermined region where the accelerator operation amount is relatively small. In addition, the accelerator operation is fully operated by timing the switching of the altitude compensator from the second operation state to the first operation state when the accelerator operation at least the possibility of sudden acceleration is detected. Since the fuel supply amount is increased stepwise in two stages during the rapid acceleration operation, the acceleration shock during the rapid acceleration operation can be reduced.

According to the second aspect of the present invention, the point at which the accelerator operation amount exceeds the threshold value is used as a reference for measuring a predetermined time regardless of the accelerator operation amount at which the rapid acceleration operation is performed. The variation in the holding time in which the supply amount is limited can be reduced, and the acceleration shock mitigation control can be stably performed.

According to the third aspect of the present invention, only when the accelerator operation when the accelerator operation amount exceeds the threshold value is caused by the rapid acceleration operation, the altitude compensation is performed after a lapse of a predetermined time from the detection. Since the device is switched from the second operating state to the first operating state, control can be performed to increase the fuel supply amount in two stages only when a rapid acceleration operation is performed.

According to the fourth aspect of the present invention, since the accelerator operation amount exceeds the threshold value when the EGR operation condition is no longer satisfied from the satisfied condition, the rapid acceleration operation is detected. In this case, the EGR determination can be used.

According to the fifth aspect of the present invention, the predetermined time is set to be equal to or longer than the time required until the EGR valve is completely closed from the valve closing command, so that the EGR valve is a negative pressure operated valve. In addition, it is possible to reduce the amount of black smoke generated due to a response delay when the EGR valve is closed during rapid acceleration.

According to the sixth aspect of the present invention, the maximum fuel supply amount when the altitude compensation device is in the second operating state is
Since the acceleration shock at the time of sudden acceleration is set to be equal to or less than the limit value that does not occur beyond the allowable amount, it is possible to avoid the occurrence of the acceleration shock exceeding the allowable amount at the time of sudden acceleration.

According to the seventh aspect of the present invention, the maximum fuel supply amount when the altitude compensation device is in the second operating state is
When the vehicle is running on flat ground, the amount of oxygen in the intake air when the EGR valve is opened is set to a value that is not excessively large enough to generate black smoke exceeding the allowable amount. The generation of black smoke can be avoided.

According to the eighth aspect of the present invention, since the predetermined time is set within one second, it is possible to reduce the acceleration shock and the amount of black smoke generated without deteriorating the acceleration performance of the vehicle.

[Brief description of the drawings]

FIG. 1 is a timing chart in control for measures at the time of sudden acceleration in a first embodiment.

FIG. 2 is a flowchart showing a program for countermeasures at the time of sudden acceleration.

FIG. 3 is a map showing a relationship between an engine speed and a fuel injection amount.

FIG. 4 is a schematic side sectional view of BACS.

FIG. 5 is a schematic diagram of a diesel engine system according to the first embodiment.

FIG. 6 is a schematic diagram of a diesel engine system according to a second embodiment.

FIG. 7 is a timing chart of control for a countermeasure at the time of sudden acceleration.

FIG. 8 is a schematic side sectional view of an ACS.

FIG. 9 is a flowchart showing a program for measures at the time of sudden acceleration in the third embodiment.

FIG. 10 is a timing chart of control for countermeasures at the time of sudden acceleration.

FIG. 11 is a map showing a relationship between an engine speed and a fuel injection amount.

FIG. 12 is a map showing a relationship between an engine speed and a fuel injection amount in the related art.

FIG. 13 is a timing chart in the EGR control.

[Explanation of symbols]

1. Diesel engine system as internal combustion engine system, 2. Diesel engine as engine, 3.
Fuel injection pump, 5: intake manifold as intake passage, 6: exhaust manifold as exhaust passage, 11 ... E
GR passage, 12: EGR valve, 22: high altitude supercharging pressure compensator (BACS) as altitude compensator, 34: detecting means,
A rotary position sensor constituting acceleration detection means and rapid acceleration detection means; 37 an ECU as control means;
... A microcomputer constituting detecting means, acceleration detecting means and sudden acceleration detecting means, 50... An advanced injection amount compensating device (ACS) as an altitude compensating device, T.

────────────────────────────────────────────────── ─── front page continued (51) Int.Cl. ⁷ identifications FI F02D 41/38 F02D 41/38 C 43/00 301 43/00 301H 301N F02M 25/07 550 F02M 25/07 550A 570 570F 570J ( 72) Inventor Keisuke Manabe 2-1-1 Toyota-cho, Kariya-shi, Aichi Prefecture Inside Toyota Industries Corporation (72) Inventor Masaaki Yamaguchi 1-Toyota-cho, Toyota-shi, Aichi Prefecture Toyota Motor Corporation Inside (72) Inventor Hattori Public person 1-1-1 Showa-cho, Kariya-shi, Aichi Prefecture In Denso Co., Ltd. (72) Inventor Shigenobu Suenaga 1-1-1, Showa-cho, Kariya city, Aichi pref. Denso Co., Ltd. (56) References , A) JP-A-7-158483 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F02D 41/00- 41/40 F02D 1/02 F02D 21/08 F02D 43/00 301

Claims (8)

(57) [Claims] 1. A first operation state in which a fuel supply amount to be supplied to an engine is altitude-compensated in accordance with an atmospheric pressure, and a second operation state in which the fuel supply amount is limited to be smaller than in the first operation state.
An altitude compensator provided so as to be able to switch to an operating state of the engine, a detecting means for detecting an accelerator operation which is at least a possibility of sudden acceleration, and an EGR passage connecting an exhaust passage and an intake passage of the engine.
An EGR device having an EGR valve for closing, and when the accelerator operation amount is within a relatively small predetermined region, the altitude compensation device is set to a second operation state;
When the accelerator operation is detected by the detection means,
At the timing when the fuel supply amount can be increased in two stages in the course of the rapid acceleration operation in which the accelerator operation is fully operated, the altitude compensating device is instructed to close the EGR valve at the timing when the fuel supply amount can be increased in two stages.
Control means for switching from the second operating state to the first operating state after a lapse of a predetermined time from the start of the internal combustion engine. 2. The acceleration control device according to claim 1, wherein the detection unit includes an acceleration detection unit that detects an acceleration operation that may cause rapid acceleration when the accelerator operation amount exceeds a threshold value. 2. The internal combustion engine system according to claim 1, wherein the altitude compensator is switched from the second operation state to the first operation state after a lapse of a predetermined time from when the accelerator operation amount exceeds the threshold value. 3. The rapid acceleration detection means for detecting that the acceleration operation when the accelerator operation amount exceeds the threshold value is caused by a rapid acceleration operation, wherein the control means comprises: Only when the rapid acceleration detection means detects the rapid acceleration operation, the altitude compensating device is moved from the second operation state to the first operation state after the lapse of the predetermined time from the detection.
The internal combustion engine system according to claim 2, wherein the internal combustion engine system is switched to the operating state. 4. Before Symbol acceleration detecting means detects that the accelerator operation amount with that longer meets the conditions satisfying the EGR operating conditions for opening the EGR valve exceeds the threshold, the control The internal combustion engine system according to claim 2 or 3, wherein the means sets the altitude compensating device to the second operating state when the accelerator operation amount satisfies the EGR operating condition. 5. The EGR valve is a negative pressure operated valve, and the predetermined time is set to be equal to or longer than a time required for the EGR valve to completely close from the valve closing command. The internal combustion engine system according to claim 1. 6. The maximum fuel supply amount when the altitude compensation device is in the second operating state is set to be equal to or less than a limit value at which acceleration shock during sudden acceleration does not exceed an allowable amount. The internal combustion engine system according to any one of claims 1 to 5. 7. The maximum fuel supply amount when the altitude compensating device is in the second operating state is equal to the E fuel amount during traveling on level ground.
The fuel cell according to any one of claims 4 to 6, wherein the amount of oxygen in the intake air at the time of opening of the GR valve is not more than a limit value that is not excessive to generate black smoke exceeding an allowable amount. An internal combustion engine system as described. 8. The internal combustion engine system according to claim 1, wherein the predetermined time is set within one second.