JP2014001694A - Fuel supply control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To continue excellent fuel injection in a fuel supply control device of an internal combustion engine even when a fuel pressure supplied to a fuel injection valve is excessively risen by a failure.SOLUTION: A fuel supply control device includes: a fuel injection valve 26 jetting fuel into a cylinder of an internal combustion engine 10; a high pressure fuel pump 30 pressurizing the fuel supplied to the fuel injection valve 26; and an EDU (64) controlling a driving current of the fuel injection valve 26. A peak value of the driving current I of the fuel injection valve 26 is set to be higher as a fuel pressure PR supplied to the fuel injection valve 26 is higher. When the fuel pressure PR is excessively risen, the peak value of the driving current I is set (fixed) to a maximum value within a predetermined current control range.

Description

  The present invention relates to a fuel supply control device for an internal combustion engine, and more particularly to a fuel supply control device for an internal combustion engine that is suitable for application to a fuel injection system that uses a high-pressure fuel pump.

  Conventionally, for example, Patent Document 1 discloses an internal combustion engine including a high-pressure fuel pump that pressurizes fuel supplied to a fuel injection valve. The high-pressure fuel pump includes a flow rate control valve that adjusts the amount of fuel discharged from the high-pressure fuel pump, a solenoid that drives the flow rate control valve, and the like. In Patent Document 1, as a failure mode of a high-pressure fuel pump, when a short-circuit failure occurs on an electric circuit (electrical wiring) that controls energization of the solenoid, the solenoid is always energized and is excessive from the high-pressure fuel pump. It is described that there is a failure mode in which a sufficient amount of fuel continues to be discharged and the fuel pressure supplied to the fuel injection valve becomes excessively high.

JP 2009-025441 A JP 2003-184616 A Japanese Patent Laid-Open No. 08-028381 JP 2007-327404 A

  The fuel injection valve is generally configured to require a large valve opening driving force as the supplied fuel pressure increases. For this reason, when the above-mentioned failure occurs in the high-pressure fuel pump and the fuel pressure is excessively increased, it becomes difficult to operate the fuel injection valve to perform fuel injection.

  The present invention has been made to solve the above-described problem, and even when the fuel pressure supplied to the fuel injection valve is excessively increased due to a failure, the fuel injection can be continued satisfactorily. An object of the present invention is to provide a fuel supply control device for an internal combustion engine.

A first aspect of the invention is a fuel supply control device for an internal combustion engine,
A fuel injection valve for injecting fuel into a cylinder of the internal combustion engine;
A high-pressure fuel pump that pressurizes the fuel supplied to the fuel injection valve;
An electric drive unit for controlling the drive current of the fuel injection valve;
With
When the fuel pressure supplied to the fuel injection valve is high, the fuel supply control device for the internal combustion engine is set so that the peak value of the drive current of the fuel injection valve is higher than when the fuel pressure is low. There,
When the fuel pressure exceeds a predetermined pressure control range and excessively rises, the peak value of the drive current of the fuel injection valve is set to the maximum value within the predetermined current control range, or the excessive increase is recognized. A fuel supply control device for an internal combustion engine, wherein the fuel supply control device is higher than the value at the time of operation.

The second invention is the first invention, wherein
The electric drive unit controls a drive current of the plurality of fuel injection valves,
When the fuel pressure is excessively increased beyond the pressure control range, the start timing of fuel injection by the plurality of fuel injection valves is fixed.

The third invention is the first or second invention, wherein
The fuel injection by the fuel injection valve is prohibited when the engine speed is higher than a predetermined speed when the fuel pressure exceeds the pressure control range.

Moreover, 4th invention is 1st or 2nd invention,
The electric drive unit controls a drive current of the plurality of fuel injection valves,
When the fuel pressure is excessively increased beyond the pressure control range, the injection intervals of the plurality of fuel injection valves are prevented from becoming shorter than the limit injection interval that becomes the overheat limit of the electric drive unit. The injection time of the valve is limited.

The fifth invention is the fourth invention, wherein
When the injection time of the plurality of fuel injection valves is limited so that the injection interval of the plurality of fuel injection valves is not shorter than the limit injection interval, the air-fuel ratio under the limited injection time is predetermined. The fuel injection by the fuel injection valve is prohibited when it is leaner than the value.

Moreover, 6th invention is set in any one of 1st-5th invention,
When the fuel pressure exceeds the pressure control range and excessively rises, the fuel injection valve is prohibited from injecting fuel divided into a plurality of times during one cycle of the internal combustion engine.

Moreover, 7th invention is set in any one of 1st-6th invention,
When the outside air temperature is equal to or lower than a predetermined value, the peak value of the drive current of the fuel injection valve is set to a maximum value within a predetermined current control range until the engine coolant temperature reaches a predetermined value, and the required fuel The pressure is set to a maximum value within a predetermined pressure control range.

In addition, an eighth invention is any one of the first to seventh inventions,
As the fuel pressure increases, the peak value of the drive current of the fuel injection valve is set to increase stepwise in at least two steps,
When either one of the actual fuel pressure and the required fuel pressure exceeds a threshold value, the peak value of the drive current of the fuel injection valve is increased, while both the actual fuel pressure and the required fuel pressure exceed a predetermined threshold value. When it falls below, the peak value of the drive current of the fuel injection valve is lowered.

The ninth invention is the eighth invention, wherein
When the peak value of the drive current of the fuel injection valve is low, the lower limit value of the required fuel injection amount is controlled to be smaller than when the peak value is high.

  According to the first invention, even when the fuel pressure supplied to the fuel injection valve is excessively increased due to a failure, the fuel injection can be continued satisfactorily.

  According to the second invention, it is possible to prevent the start timing of fuel injection by the plurality of fuel injection valves from varying depending on the injection conditions. As a result, it is possible to prevent the injection interval from being narrowed transiently, so that it is possible to prevent the cooling time of the electric drive unit for the fuel injection valve from becoming transiently short. For this reason, it becomes possible to prevent a failure due to overheating of the electric drive unit.

  According to the third aspect of the invention, the injection interval is narrowed due to the high engine speed, and the failure of the electric drive unit can be avoided in a situation where it is difficult to avoid overheating of the electric drive unit.

  According to the fourth aspect, overheating of the electric drive unit can be prevented.

  According to the fifth invention, even when the injection interval is short, as long as the air-fuel ratio in the state in which the limit injection interval is ensured does not become significantly lean beyond the lean determination value, it is higher than the stoichiometric air-fuel ratio. A region in which lean operation is performed with a lean air-fuel ratio is provided. Thereby, compared with the method of the third invention in which the determination of the fuel cut is performed based on the level of the engine speed, the region where the fuel cut is performed can be narrowed (the opportunity for the fuel cut can be reduced). Therefore, it is possible to increase the vehicle speed during retreating.

  According to the sixth aspect of the invention, it is possible to prevent a failure due to overheating of the electric drive unit by avoiding the narrowing of the injection interval due to the divided injection.

  According to the seventh aspect of the invention, by setting the peak value of the drive current of the fuel injection valve to the maximum value at the low outside air temperature and setting the required fuel pressure to the maximum value, the fuel injection valve can be used by using a high current. The fuel can be prevented from adhering to the wall surface in the cylinder by atomizing the injected fuel by increasing the fuel pressure while ensuring the opening and closing operability of the fuel. Thereby, the fuel dilution of engine oil can be suppressed. Furthermore, according to the present invention, the control of the peak value of the drive current and the required fuel pressure at low outside air temperature is performed only until the engine coolant temperature reaches the predetermined value. In other words, since the above-described control is limited to low temperature starting when the outside air temperature is low and the temperature of the electric drive unit itself is low, the fuel dilution is performed while avoiding the failure of the electric drive unit due to overheating. It becomes possible to suppress.

  According to the eighth invention, the switching of the peak value of the drive current to a higher value is immediately performed on the condition that one of the two pieces of information, that is, the actual fuel pressure and the required fuel pressure exceeds the first threshold value. Implemented (permitted). As a result, a high drive current can be easily secured against changes in the actual fuel pressure and the required fuel pressure. For this reason, it is possible to prevent the fuel injection from being disabled due to a shortage of the drive current with respect to fluctuations in the actual fuel pressure. The switching of the peak value of the drive current to a lower value is performed (permitted) on condition that both the actual fuel pressure and the required fuel pressure are below the second threshold value. Thus, the drive current is lowered after confirming that both the actual fuel pressure and the required fuel pressure have been reliably reduced. Thereby, it is possible to prevent hunting for switching the drive current. Further, it is possible to prevent the fuel injection from being disabled due to the shortage of the drive current against the fluctuation of the actual fuel pressure.

  According to the ninth aspect of the present invention, it is possible to prevent the fuel injection with the required amount from being disabled under the situation where the drive current is high but the required fuel injection amount is small.

It is a figure for demonstrating the system configuration | structure of an internal combustion engine provided with the fuel supply control apparatus which concerns on Embodiment 1 of this invention. It is a figure for demonstrating the main structures of the fuel supply control apparatus which concerns on Embodiment 1 of this invention. It is a figure showing the example of a setting of the drive current (peak value) of a fuel injection valve with respect to the change of a fuel pressure (fuel pressure). It is a flowchart of the main routine performed in Embodiment 1 of the present invention. It is a flowchart of the fuel cut process subroutine performed in Embodiment 1 of this invention. It is a flowchart of the fuel cut process subroutine performed in Embodiment 2 of this invention. It is a flowchart of the routine performed in Embodiment 3 of the present invention. It is a flowchart of the routine performed in Embodiment 4 of this invention.

Embodiment 1 FIG.
[System Configuration of Embodiment 1]
FIG. 1 is a diagram for explaining a system configuration of an internal combustion engine 10 including a fuel supply control device according to Embodiment 1 of the present invention. The internal combustion engine 10 is an in-line four-cylinder gasoline engine (an example), which is mounted on a vehicle and used as a power source. An intake passage 12 and an exhaust passage 14 communicate with the combustion chamber of the internal combustion engine 10.

  An air cleaner 16 is disposed in the vicinity of the inlet of the intake passage 12. An air flow meter 18 that outputs a signal corresponding to the flow rate of air sucked into the intake passage 12 is provided in the intake passage 12 on the downstream side of the air cleaner 16. A compressor 20 a of the turbocharger 20 is disposed in the intake passage 12 on the downstream side of the air flow meter 18. The turbine 20 b of the turbocharger 20 is disposed in the exhaust passage 14.

  An intercooler 22 that cools the air compressed by the compressor 20a is disposed in the intake passage 12 on the downstream side of the compressor 20a. An electronically controlled throttle valve 24 is provided in the intake passage 12 downstream of the intercooler 22. Each cylinder of the internal combustion engine 10 is provided with an electromagnetically driven fuel injection valve 26 for directly injecting fuel into the cylinder (combustion chamber). The fuel injection valve 26 of each cylinder is connected to a common delivery pipe 28. A high pressure fuel pressurized by a high pressure fuel pump 30 (see FIG. 2) is supplied into the delivery pipe 28, and fuel is supplied from the delivery pipe 28 to the fuel injection valve 26 of each cylinder. It has become.

FIG. 2 is a diagram for explaining the main configuration of the fuel supply control apparatus according to Embodiment 1 of the present invention.
As shown in FIG. 2, the fuel in the fuel tank 34 pumped up by the low-pressure fuel pump (feed pump) 32 is supplied to the suction port 30 a of the high-pressure fuel pump 30 through the fuel pipe 36. The discharge port 30 b of the high-pressure fuel pump 30 and the delivery pipe 28 are connected by a fuel pipe 38.

  The high-pressure fuel pump 30 is fixed to a fuel pressurizing chamber 30c that can selectively communicate with the suction port 30a and the discharge port 30b, an electromagnetic spill valve 30d that opens and closes the suction port 30a, and the camshaft 40 of the internal combustion engine 10. The pressurizing cam 30e, a plunger 30f that changes the volume of the fuel pressurizing chamber 30c by reciprocating with the rotation of the pressurizing cam 30e, and a press contact spring 30g that biases the plunger 30f toward the pressurizing cam 30e. And a check valve 30h disposed in the discharge port 30b. The electromagnetic spill valve 30d is opened by the urging force of the urging spring 30d2 when the energization to the built-in solenoid 30d1 is turned off, while the solenoid 30d1 is energized when the energization to the solenoid 30d1 is turned on. The valve is closed by overcoming a drag force such as the spring force of the biasing spring 30d2. The check valve 30h is configured to allow fuel to be discharged from the fuel pressurization chamber 30c through the discharge port 30b and to prevent backflow of fuel from the discharge port 30b to the fuel pressurization chamber 30c. ing.

Referring to FIG. 1 again, the description of the system configuration of the internal combustion engine 10 will be continued.
The system shown in FIG. 1 includes an ECU (Electronic Control Unit) 50. In addition to the air flow meter 18 described above, various inputs for detecting the operating state of the internal combustion engine 10 such as the fuel pressure sensor 52, the A / F sensor 54, the crank angle sensor 56, and the coolant temperature sensor 58 are input to the input portion of the ECU 50. Sensor is connected. The fuel pressure sensor 52 is attached to the delivery pipe 28 in order to detect the fuel pressure supplied to the fuel injection valve 26 of each cylinder. The A / F sensor 54 is a sensor for detecting the air-fuel ratio of the exhaust gas flowing through the exhaust passage 14, the crank angle sensor 56 is a sensor for detecting the engine speed, and the cooling water temperature sensor 58 is A sensor for detecting the engine coolant temperature. In addition, an outside air temperature sensor 60 for detecting outside air temperature is connected to the input unit of the ECU 50. On the other hand, in addition to the throttle valve 24, the fuel injection valve 26, and the electromagnetic spill valve 30d described above, various outputs for controlling the operation of the internal combustion engine 10 such as a spark plug 62 for igniting the air-fuel mixture are provided at the output portion of the ECU 50. Actuator is connected. More specifically, the fuel injection valve 26 of each cylinder is connected to the ECU 50 via an electric drive unit (hereinafter referred to as “EDU (Electrical Driver Unit)”) 64 for driving the fuel injection valve 26. ing. The ECU 50 controls the operating state of the internal combustion engine 10 by driving the various actuators according to the sensor output and a predetermined program.

[Basic operation of high-pressure fuel pump]
Next, the basic operation of the high-pressure fuel pump 30 when the high-pressure fuel pump 30 having the above-described configuration is functioning normally will be described. In the following description, the position of the plunger 30f when the volume in the fuel pressurizing chamber 30c is reduced most (that is, when the plunger 30f is raised most in FIG. 2) is referred to as “top dead center of the plunger 30f” and vice versa. In addition, the position of the plunger 30f when the volume in the fuel pressurizing chamber 30c is most expanded (that is, when the plunger 30f is lowered most in FIG. 2) is referred to as “bottom dead center of the plunger 30f”.

  In the high-pressure fuel pump 30 having the configuration shown in FIG. 2, the plunger 30f reciprocates twice in the fuel pressurizing chamber 30c while the pressurizing cam 30e rotates once. In the high-pressure fuel pump 30, the energization of the solenoid 30d1 is turned off during the period in which the plunger 30f is lowered and the volume of the fuel pressurizing chamber 30c is increased. As a result, the electromagnetic spill valve 30d is opened, and the intake-side fuel pipe 36 and the fuel pressurizing chamber 30c communicate with each other. When the plunger 30f is lowered in this state, the pressure in the fuel pressurizing chamber 30c is lowered, so that the fuel is sucked into the fuel pressurizing chamber 30c.

  The fuel sucked into the fuel pressurizing chamber 30c flows back into the fuel pipe 36 on the suction side when the plunger 30f starts to rise again after passing through the bottom dead center with the electromagnetic spill valve 30d opened. . More specifically, since the pressure in the fuel pipe 36 on the suction side is lower than the pressure in the fuel pipe 38 on the discharge side, the fuel flows backward to the fuel pipe 36 side. At this time, the fluid force of the fuel that flows backward from the fuel pressurizing chamber 30c toward the fuel pipe 36 acts on the electromagnetic spill valve 30d. The spring force of the urging spring 30d2 is set so that the electromagnetic spill valve 30d is not closed by this fluid force.

  When the solenoid 30d1 is energized while the plunger 30f is being raised or at the start of raising, the suction force of the solenoid 30d1 overcomes the spring force of the urging spring 30d2, and the electromagnetic spill valve 30d is closed. As a result, the fuel in the fuel pressurizing chamber 30c is pressurized as the plunger 30f moves up. When the fuel pressure in the fuel pressurizing chamber 30c becomes higher than the fuel pressure in the fuel pipe 38 on the discharge side, the check valve 30h opens and the fuel is pumped to the delivery pipe 28 side (fuel injection valve 26 side). The Therefore, if the electromagnetic spill valve 30d is closed when the plunger 30f is located at the bottom dead center, the maximum amount of fuel can be discharged. Then, while the plunger 30f is being lifted, the fuel discharge amount to the delivery pipe 28 can be adjusted to be smaller as the closing timing of the electromagnetic spill valve 30d is delayed.

  As described above, the fuel discharge amount can be adjusted by changing the valve closing timing of the electromagnetic spill valve 30d by energizing the solenoid 30d1 during the ascending period of the plunger 30f. During operation of the internal combustion engine 10, the electromagnetic spill valve 30d is controlled so that the fuel pressure supplied to the fuel injection valve 26 becomes a target value based on the value detected by the fuel pressure sensor 52. More specifically, the fuel pressure is basically controlled within a predetermined pressure control range so as to increase as the load on the internal combustion engine 10 increases.

[Relationship between fuel injector drive current and fuel pressure]
FIG. 3 is a diagram showing a setting example of the drive current (peak value) of the fuel injection valve 26 with respect to the change of the fuel pressure (fuel pressure).
As shown in FIG. 3A, in the system of this embodiment, the peak value of the drive current of the fuel injection valve 26 is set so as to change according to the fuel pressure within a predetermined current control range. . In FIG. 3A, the peak value of the drive current of the fuel injection valve 26 is set to be higher in three stages of low, high, and max as the fuel pressure increases. Note that the maximum value (Max) of the drive current is a value set in advance so that the EDU 64 does not fail in a region below a predetermined engine speed in consideration of the environmental conditions of the internal combustion engine 10.

  Instead of the above settings, the settings shown in FIG. 3B may be used. In FIG. 3B, in the region where the fuel pressure is lower than the high fuel pressure region using Max, the peak value of the drive current is set to continuously increase as the fuel pressure increases. By making the drive current of the fuel injection valve 26 variable with respect to the fuel pressure by the method shown in FIG. 3A or FIG. 3B, the minimum injection from the fuel injection valve 26 at the time of low fuel pressure The amount of fuel can be reduced.

  The peak value of the driving current here is a period during which the driving current is supplied to the fuel injection valve 26 for one valve opening operation (that is, one fuel injection). It is the peak value of the drive current in the middle. In general, the fuel injection valve 26 is supplied with a relatively high current at the initial stage of energization (to a solenoid provided in the fuel injection valve 26) for the purpose of quickly opening the valve, and thereafter, in order to maintain the valve opening state. Since a relatively low current is supplied, the drive current value usually shows a peak at the initial stage of energization. Moreover, ECU50 shall be provided with the electric current detection part (illustration omitted) for detecting a drive current.

[About failures that may occur in high-pressure fuel pumps]
As one of the failure modes that can occur in the high-pressure fuel pump 30, for example, when a short-circuit failure occurs on the electric circuit that controls the energization of the solenoid 30d1 of the electromagnetic spill valve 30d, the solenoid 30d1 is always energized. There is something. In such a state, in the stroke in which the plunger 30f is lowered, even if a force is applied to the solenoid 30d1 to close the electric spill valve 30d, the electric spill from the suction port 30a side is more than this force. The resultant force of the intake fuel pressure applied in the direction to open the valve 30d, the spring force of the urging spring 30d2, and the negative pressure generated in the fuel pressurizing chamber 30c as the plunger 30f descends increases. As a result, the electric spill valve 30d remains open during the downward stroke of the plunger 30f, and fuel is sucked into the fuel pressurizing chamber 30c. After that, when the plunger 30f reaches the bottom dead center, the fuel does not flow into the fuel pressurizing chamber 30c. Therefore, the force generated by the solenoid 30d1 overcomes the spring force of the biasing spring 30d2, and the electric spill valve 30d is closed. Is done. For this reason, the maximum amount of fuel is discharged. When the above-described failure occurs by such an operation, an excessive amount of fuel is continuously discharged from the high-pressure fuel pump 30 with the discharge amount of the fuel from the high-pressure fuel pump 30 being fixed at the maximum value. become.

  The fuel injection valve 26 is generally configured to require a large valve opening driving force as the supplied fuel pressure increases. For this reason, when the above-mentioned failure occurs in the high-pressure fuel pump 30 and the fuel pressure is excessively increased, it becomes difficult to operate the fuel injection valve to perform fuel injection.

[Characteristic Control in Embodiment 1]
Therefore, in the present embodiment, when the fuel pressure exceeds the pressure control range due to the occurrence of a failure in the high-pressure fuel pump 30, the peak value of the drive current of the fuel injection valve 26 of each cylinder is set to the current control. The maximum value (Max) within the range was set (fixed). More specifically, if the peak value of the drive current at the time when it is determined that the fuel pressure has increased excessively is controlled to Low or High, the peak value of the drive current becomes the maximum value (Max). As enhanced. If the peak value of the drive current at the time when it is determined that the fuel pressure has risen excessively has already been controlled to the maximum value (Max), the peak value of the drive current is maintained at the maximum value (Max). The

  In the present embodiment, when the fuel pressure is excessively increased, the peak value of the drive current is fixed at the maximum value (Max) as described above, and further, the fuel for each cylinder controlled by the EDU (injector driver) 64 is used. The start timing of fuel injection by the injection valve 26 is fixed.

  In the present embodiment, when the fuel pressure is excessively increased, the peak value of the drive current is fixed at the maximum value (Max) as described above, and the fuel injection valve 26 of each cylinder is further connected to the internal combustion engine 10. It is prohibited to inject fuel by dividing into multiple times during one cycle (hereinafter simply referred to as “divided injection”).

  Further, in this embodiment, when the fuel pressure is excessively increased, the peak value of the drive current is fixed at the maximum value (Max) as described above, and further, when the engine speed is higher than the predetermined speed. The fuel injection by the fuel injection valve 26 of each cylinder is prohibited (that is, the fuel cut is executed).

  FIG. 4 is a flowchart showing a main routine executed by ECU 50 in the first embodiment of the present invention. This routine is repeatedly executed every predetermined control cycle.

  In the main routine shown in FIG. 4, first, the current engine speed NE is acquired using the crank angle sensor 56 (step 100). Next, the current drive current I of the fuel injection valve (injector) 26 controlled by the EDU 64 is acquired using the current detector (step 102). Next, the current fuel pressure (hereinafter sometimes referred to as “fuel pressure PR”) is acquired using the fuel pressure sensor 52 (step 104).

  Next, a high-pressure pump failure state flag exfpmp that is turned on when a high-pressure pump failure state (state in which a failure has occurred in the high-pressure fuel pump 30) is established and turned off when the high-pressure fuel pump 30 is normal is set. Obtained (step 106). The ECU 50 always determines whether or not the high-pressure pump fail state is established by a routine (not shown) that starts in synchronization with this routine. Specifically, when the fuel pressure sensor 52 detects that the fuel pressure PR has exceeded the pressure control range, the high pressure pump failure state flag exfpmp is turned on. Next, the previous high-pressure pump failure state flag exfpmpo (when the control period comes) is acquired (step 108).

  Next, it is determined whether or not the previous high-pressure pump fail state flag exfpmpo is OFF (step 110). As a result, if this determination is true, it is determined whether or not the current high-pressure pump failure state flag exfpmp (corresponding to the time when the current control cycle comes) is OFF (step 112).

  If the determination in step 112 is true (that is, if it is determined that the high pressure fuel pump 30 has not failed (excessive increase in fuel pressure PR) both in the previous time and this time), the previous high pressure pump failure state flag is determined. The flag exfpmpo is updated by storing the current (current) fail state in exfpmpo (step 114). In this case, the flag exfpmpo is turned off.

  On the other hand, if the determination in step 110 is not established, as in step 112, it is determined whether or not the current high-pressure pump fail state flag exfpmp is OFF (step 116).

  If the determination in step 112 is not satisfied (that is, if the high-pressure fuel pump 30 has not failed in the previous time but it is determined that a failure has occurred when the current control cycle has arrived), or the determination in step 116 is When it is not established (that is, when it is determined that the high-pressure fuel pump 30 has failed both in the previous time and this time), the process of step 118 is executed. In step 118, it is determined whether or not a high fuel pressure state in which the fuel pressure PR is excessively increased, for example, a state in which the fuel pressure PR is higher than 22 MPa continues (step 118).

  As a result, when it is determined in step 118 that the high fuel pressure state continues, the drive current target value It of the fuel injection valve 26 is set (fixed) to the maximum value (Max) (step 120). Furthermore, in this case, the fuel injection start timing INJt of the fuel injection valve 26 of each cylinder is fixed at a predetermined timing (for example, 360 ° BTDC (compression top dead center)) (step 122).

  If the determination at step 118 is true, the processes at steps 124, 126, and 114 are further executed in order. In step 124, split injection by the fuel injection valve 26 of each cylinder is prohibited (step 124). In step 126, a fuel cut processing subroutine shown in FIG. 5 described later is executed. In step 114 executed in this case, the previous high-pressure pump failure state flag exfpmpo is updated to ON.

FIG. 5 is a flowchart showing a fuel cut processing subroutine executed by ECU 50 in the first embodiment of the present invention.
In the subroutine shown in FIG. 5, it is determined whether or not the engine speed NE is higher than a predetermined speed (for example, 4000 rpm) (step 200). As a result, if it is at a high engine speed at which this determination is established, a fuel cut is executed for each cylinder (step 202).

  In the main routine shown in FIG. 4, when the determination of step 116 is established (that is, it was determined that a failure occurred in the high-pressure fuel pump 30 in the previous time but did not occur (resolved) when the current control cycle arrives). In this case, the drive current target value It of the fuel injection valve 26 of each cylinder is returned to a value when the high-pressure fuel pump 30 is normal (a value corresponding to the fuel pressure PR shown in FIG. 3) (step). 128). In this case, the processes of steps 130, 132 and 114 are then executed in order.

  In step 130, the fuel injection start timing INJt by the fuel injection valve 26 of each cylinder is returned to the normal value. In step 132, execution of the fuel cut processing subroutine is stopped. For this reason, when the fuel cut is executed by the processing of this subroutine, the fuel cut is stopped. In step 114 executed in this case, the previous high-pressure pump fail state flag exfpmpo is updated to OFF.

  According to the main routine shown in FIG. 4 described above, when the high fuel pressure state in which the fuel pressure PR is excessively high is established, the drive current target value It of the fuel injection valve 26 of each cylinder is the maximum value (Max). Set to Thereby, even when the fuel pressure PR is excessively increased due to a failure of the high-pressure fuel pump 30, it is possible to prevent the fuel injection by the fuel injection valve 26 from being disabled. Further, even when the fuel pressure PR does not become impossible due to excessive increase in the fuel pressure PR, the control accuracy of the fuel injection amount can be ensured as much as possible by ensuring the valve opening operability of the fuel injection valve 26.

  On the other hand, when the drive current I is controlled to the maximum value as described above as a countermeasure when the fuel pressure PR rises excessively, the amount of heat generation increases, so the EDU 64 overheats and a failure occurs in the heat-sensitive electronic component. There is a concern that it will occur. In response to such a problem, according to the main routine, when the fuel pressure PR is excessively increased, the start timing of fuel injection by the fuel injection valve 26 of each cylinder controlled by the EDU 64 is fixed. Thereby, it is possible to prevent the fuel injection start timing INJt of each cylinder from varying depending on the injection conditions. As a result, it is possible to avoid the injection interval from becoming transiently narrow, so that the cooling time of the EDU 64 can be prevented from becoming transiently short. For this reason, a failure due to overheating of the EDU 64 can be prevented.

  Further, the concern about overheating of the EDU 64 due to the control of the drive current I to the maximum value becomes more conspicuous because the cooling time of the EDU 64 is likely to be insufficient at the time of performing the divided injection in which the injection interval is shortened. In response to such a problem, according to the main routine, when the fuel pressure PR is excessively increased, divided injection is prohibited. Thereby, since it is possible to avoid the injection interval from being narrowed by the divided injection, it is possible to prevent a failure due to overheating of the EDU 64. More specifically, since the region where the EDU 64 is not overheated can be expanded by prohibiting the divided injection, the vehicle speed during the retreat travel of the vehicle accompanying the failure of the high pressure fuel pump 30 can be increased.

  Further, since the injection interval (time base) becomes shorter as the engine speed increases, the EDU 64 tends to overheat when the drive current I is controlled to the maximum value. In response to such a problem, under the situation where the fuel pressure PR has excessively increased, according to the subroutine shown in FIG. 5, when the engine speed is higher than the predetermined speed, the fuel cut is executed. As a result, failure of the EDU 64 can be avoided under circumstances where it is difficult to avoid overheating of the EDU 64 due to the high engine speed.

  In the first embodiment described above, when the fuel pressure PR is excessively increased, the drive current target value It (peak value) of the fuel injection valve 26 of each cylinder is set to the maximum value (Max) within a predetermined current control range. Was set to. However, the control of the drive current of the fuel injection valve that is performed when the fuel pressure is excessively increased in the present invention is not limited to the above aspect, and the peak of the drive current is larger than the value when the excessive increase of the fuel pressure PR is recognized. The value may be increased. In addition, the mode in which the peak value of the drive current is made higher than the value when an excessive increase in the fuel pressure PR is recognized is not limited to the one that increases the peak value within the normal current control range. What raises the said peak value toward the value (value which can be temporarily provided) higher than the maximum value in the current control range at the time may be included.

Embodiment 2. FIG.
Next, a second embodiment of the present invention will be described with reference mainly to FIG.
The system of the present embodiment uses the hardware configuration shown in FIGS. 1 and 2 and the relationship between the drive current and the fuel pressure shown in FIG. 3 (A) or FIG. 3 (B). 5 can be realized by executing a subroutine shown in FIG. 6 described later in place of the subroutine shown in FIG.

  That is, in the system of this embodiment, when the fuel pressure PR is excessively increased, the peak value of the drive current is fixed at the maximum value (Max) as described above in the first embodiment, and the fuel injection of each cylinder is further performed. It is characterized in that the injection time of the fuel injection valve 26 of each cylinder is limited so that the injection interval (time base) of the valve 26 does not become shorter than the limit injection interval that becomes the overheating limit of the EDU 64. ing.

  FIG. 6 is a flowchart showing a fuel cut processing subroutine executed by ECU 50 in the second embodiment of the present invention. This routine is repeatedly started at a timing immediately after the end of fuel injection in each cylinder.

  In the subroutine shown in FIG. 6, first, the injection end timing EOIO of the fuel injection in the cylinder in which the fuel injection has ended immediately before the start of this routine (hereinafter referred to as “pre-injection cylinder” for convenience of explanation) is acquired ( Step 300). Next, the fuel injection start timing SOI of the “next injection cylinder”, that is, the cylinder in which fuel injection is scheduled after the previous injection cylinder is acquired (step 302). The start timing and end timing of fuel injection for each cylinder are determined based on injection conditions set in advance in relation to the operating state of the internal combustion engine 10 and the like.

  Next, the injection interval INT of the fuel injection between the previous injection cylinder and the next injection cylinder is calculated as a difference obtained by subtracting the injection end timing EOIO from the injection start timing SOI acquired as described above ( Step 304).

  Next, it is determined whether or not the calculated injection interval INT is shorter than a predetermined time (for example, 4000 μsec) (step 306). The predetermined time used in this step 306 is a value set in advance as a limit injection interval that becomes the overheating limit of the EDU 64 (more specifically, it becomes a limit in terms of suppressing overheating of the EDU 64).

  If the determination in step 306 is true, that is, if it is determined that the injection interval INT will be shorter than the limit injection interval unless any correction is made to the injection start timing SOI of the next injection cylinder, the step Steps 308 to 318 are executed in order. In this case, step 320 is executed on condition that step 318 is established.

  In step 308, the injection start timing SOI ′ necessary to ensure the limit injection interval (here, 4000 μsec) as the injection interval INT between the previous injection cylinder and the next injection cylinder is calculated by the formula (SOI ′ = SOI− It is calculated using (INT + 4000). The calculated injection start timing SOI ′ is used in the next injection cylinder unless the determination in the following step 318 is established.

  In step 310, an injection time TAUSTI for realizing the fuel injection amount necessary for realizing the stoichiometric air-fuel ratio under the current intake air amount acquired by using the air flow meter 18 in relation to the current fuel pressure PR. Is calculated. Next, at step 312, the injection time TAU of the next injection cylinder according to the current injection condition is acquired.

  In step 314, the injection time TAU ′ necessary for securing the limit injection interval (here, 4000 μsec) as the injection interval INT between the next injection cylinder and the next injection cylinder is calculated by the formula (TAU ′ = TAU + INT). -4000). Next, at step 316, the air-fuel ratio ABYF ′ under the injection time TAU ′ is calculated using an arithmetic expression (ABYF ′ = 14.5 × TAUSTI ÷ TAU ′). The calculated injection time TAU ′ is used in the next injection cylinder unless the determination in the following step 318 is established.

  Next, in step 318, it is determined whether or not the calculated air-fuel ratio ABYF ′ is greater than a predetermined lean determination value (for example, 17) (is lean). As a result, when this determination is established, in step 320, a fuel cut for the next injection cylinder is executed.

  According to the subroutine shown in FIG. 6 described above, when the injection interval INT between the previous injection cylinder and the next injection cylinder is shorter than the limit injection interval, the next injection cylinder is set so as to ensure the limit injection interval. The injection start time SOI is corrected to the injection start time SOI ′. In this case, the injection time TAU is corrected to the injection time TAU ′ so that the limit injection interval is secured as the injection interval INT between the next injection cylinder and the next injection cylinder. According to such processing, the injection time TAU can be limited so that the injection interval INT between the cylinders adjacent to each other in the explosion order does not exceed the limit injection interval that becomes the overheating limit of the EDU 64. Thereby, overheating prevention of EDU64 can be aimed at.

  Further, according to the above subroutine, when the air-fuel ratio ABYF ′ under the injection interval TAU ′ limited to prevent overheating of the EDU 64 is leaner than a predetermined lean determination value, the next injection cylinder is targeted. The fuel cut is executed. In other words, according to such a process, even when the injection interval INT is short, the air-fuel ratio ABYF ′ in a state where the limit injection interval is secured does not exceed the lean determination value and does not become lean significantly. A region is provided in which lean operation is performed at an air-fuel ratio leaner than the stoichiometric air-fuel ratio. Thereby, compared with the method of Embodiment 1 which judges execution of fuel cut based on the level of engine speed, the area | region which performs fuel cut can be narrowed (the opportunity to perform fuel cut can be reduced). Therefore, it becomes possible to increase the vehicle speed during retreating.

Embodiment 3 FIG.
Next, Embodiment 3 of the present invention will be described with reference mainly to FIG.
The system of the present embodiment uses the hardware configuration shown in FIGS. 1 and 2 and the relationship between the drive current and the fuel pressure shown in FIG. 3 (A) or FIG. 3 (B). This can be realized by executing the routine shown in FIG. The control of this embodiment can be executed on an actual machine in parallel with the control of the first or second embodiment described above.

  Specifically, in the present embodiment, at a low outside air temperature at which the outside air temperature becomes a predetermined value (for example, −20 ° C.) or less, until the engine coolant temperature reaches a predetermined value (for example, 60 ° C.), The drive current target value It (peak value) of the fuel injection valve 26 is set to a maximum value within a predetermined current control range (for example, the current control range shown in FIG. 3), and the required fuel pressure PRt is a predetermined pressure control range. It is characterized by being set to the maximum value.

  FIG. 7 is a flowchart showing a routine executed by ECU 50 in the third embodiment of the present invention. This routine is repeatedly executed every predetermined control cycle.

  In the routine shown in FIG. 7, first, the current outside temperature THAM is acquired using the outside temperature sensor 60 (step 400). Next, it is determined whether or not the acquired outside air temperature THAM is equal to or lower than a predetermined value (for example, −20 ° C.) (step 402).

  If it is determined in step 402 that the temperature is not low, the target drive current value It (peak value) of the fuel injection valve 26 of each cylinder corresponds to the normal value (that is, the current fuel pressure PR). Value) (step 404). Next, the required fuel pressure PRt is set to a normal value (that is, a value corresponding to the current operating state (load or the like) of the internal combustion engine 10) (step 406).

  On the other hand, if it is determined in step 402 that the temperature is low, the current engine coolant temperature THW is acquired using the coolant temperature sensor 58 (step 408). Next, it is determined whether or not the acquired cooling water temperature THW is equal to or lower than a predetermined value (for example, 60 ° C.) (step 410). The EDU 64 is disposed in a place (engine room) that is affected by the heat generated by the internal combustion engine 10. For this reason, the predetermined value in this step 410 is set in advance as a value that can prevent the EDU 64 in use at a high current from being overheated in a situation where the atmospheric temperature of the EDU 64 is increased due to the warm-up of the internal combustion engine 10. It is a set value.

  If it is determined in step 410 that the engine coolant temperature THW is not more than the predetermined value, the drive current target value It (peak value) of the fuel injection valve 26 of each cylinder is set (fixed) to the maximum value (Max). (Step 412). In this case, the required fuel pressure PRt is further set to a maximum value (for example, 22 MPa) (step 414). On the other hand, when the determination in step 410 is not established due to the warm-up of the internal combustion engine 10, normal processing in steps 404 and 406 is executed.

  When the internal combustion engine 10 is cold at a low outside air temperature, the fuel injected by the fuel injection valve 26 easily adheres to the wall surface in the cylinder, and as a result, the oil is easily diluted by the attached fuel. Become. With respect to such a problem, according to the routine shown in FIG. 7 described above, the drive current target value It (peak value) of the fuel injection valve 26 is set to the maximum value at the low outside air temperature, and the required fuel pressure PRt is set to the maximum value. By setting the maximum value, the operation of opening and closing the fuel injection valve 26 is reliably ensured by using a high current, and the adhesion of fuel to the wall surface in the cylinder is suppressed by atomizing the injected fuel by increasing the fuel pressure. can do. Thereby, the fuel dilution of engine oil can be suppressed. Further, according to the routine, the control of the drive current target value It and the required fuel pressure PRt at a low outside air temperature is performed only until the engine coolant temperature THW reaches the predetermined value. In other words, the above control is limited to the low temperature start when the outside air temperature is low and the temperature of the EDU 64 itself is low, so that fuel dilution can be suppressed while avoiding failure of the EDU 64 due to overheating. Become.

Embodiment 4 FIG.
Next, Embodiment 3 of the present invention will be described with reference mainly to FIG.
The system of the present embodiment uses the hardware configuration shown in FIGS. 1 and 2 and the relationship between the drive current and the fuel pressure shown in FIG. 3A, and the ECU 50 has a routine shown in FIG. It can be realized by executing. The control of the present embodiment can be executed on an actual machine in parallel with the control of the first, second, or third embodiment described above.

  By the way, by lowering the drive current I of the fuel injection valve, the minimum injection amount (injection amount lower limit value) that can be injected by the fuel injection valve can be reduced, so that the fuel pressure PR that is normally used can be increased. However, when the drive current I is lowered, the maximum fuel pressure at which fuel can be injected also decreases. As a countermeasure against this, as shown in FIG. 3A as an example, a setting is made to increase the drive current I (peak value) of the fuel injection valve 26 stepwise (at least in two steps) as the fuel pressure PR increases. It is preferable to use it. When such a setting is provided, when the drive current I is switched according to the fuel pressure PR, if the request (target) fuel pressure PRt preset by a map or the like is used, the actual fuel pressure PR is large. There are concerns that the following problems may occur under changing circumstances. That is, when the drive current I is switched, if the actual fuel pressure PR varies higher than the required fuel pressure PRt, the drive current I for opening and closing the fuel injection valve 26 under the actual fuel pressure PR is low. There is a concern that a situation may occur in which injection becomes impossible.

  Therefore, in the present embodiment, an internal combustion engine having a setting in which the drive current I (peak value) of the fuel injection valve 26 increases stepwise as the fuel pressure PR increases (for example, the setting shown in FIG. 3A). At 10, the following control is performed. That is, the switching of the peak value of the drive current I from Low to High is performed when either one of the actual fuel pressure PR and the required (target) fuel pressure PRt exceeds a predetermined first threshold value. On the other hand, the switching of the peak value of the drive current I from High to Low is performed when both the actual fuel pressure PR and the required (target) fuel pressure PRt are below a predetermined second threshold value.

  Further, in the present embodiment, the lower limit value QMIN of the required fuel injection amount is made variable according to the peak value of the drive current I of the fuel injection valve 26. More specifically, the injection amount lower limit value QMIN is changed so as to decrease as the peak value of the drive current I decreases.

  FIG. 8 is a flowchart showing a routine executed by ECU 50 in the fourth embodiment of the present invention. This routine is repeatedly executed every predetermined control cycle.

  In the routine shown in FIG. 8, first, the current actual fuel pressure PR is acquired using the fuel pressure sensor 52 (step 500). Next, the required fuel pressure PRt corresponding to the current injection condition is acquired according to a predetermined map (not shown) (step 502).

  Next, it is determined whether or not the actual fuel pressure PR has exceeded a predetermined first threshold (for example, 8 MPa) (step 504). This first threshold value is a value used as a judgment material when the drive current I (peak value) is switched from Low to High. If the determination in step 504 is true, the routine proceeds to step 508. Conversely, if the determination in step 504 is not established, it is determined whether or not the required fuel pressure PRt exceeds the first threshold value (step 506). As a result, when the determination in step 506 is established, the processing in step 506 proceeds to step 508.

  As described above, the process of step 508 is executed when the determination of either one of steps 504 and 506 is established. In step 508, the drive current target value It of the fuel injection valve 26 of each cylinder is changed (increased) from Low to High.

  On the other hand, if the determination in step 504 or 506 is not established, it is determined whether or not the actual fuel pressure PR has fallen below a predetermined second threshold (for example, 7 MPa) (step 510). The second threshold value is a value used as a judgment material when switching the drive current I (peak value) from High to Low. If the determination in step 510 is true, it is determined whether the required fuel pressure PRt has fallen below the second threshold (step 512).

  As a result, when both the determinations in steps 510 and 512 are satisfied, the drive current target value It of the fuel injection valve 26 of each cylinder is changed (lowered) from High to Low (Step 514). After the process of step 514 or 508 is executed, or when the determination of step 510 or step 512 is not established, the process of this routine is advanced to step 516.

  In step 516, a lower limit value QMIN of the required fuel injection amount is calculated. This lower limit value QMIN is determined as a function of the drive current target value It (peak value) of the fuel injection valve 26. More specifically, the injection amount lower limit value QMIN is set to be smaller as the drive current target value It (peak value) is lower. Next, the current fuel injection amount QINJ (required value according to the current injection condition) is acquired (step 518).

  Next, it is determined whether or not the current fuel injection amount QINJ is smaller than the injection amount lower limit value QMIN using the values obtained by the processing of steps 516 and 518 (step 520). As a result, when this determination is satisfied, the fuel injection amount QINJ is corrected so as to become the injection amount lower limit value QMIN (step 522).

  According to the routine shown in FIG. 8 described above, switching of the peak value of the drive current I (target value It) from Low to High is performed by either one of the two pieces of information of the actual fuel pressure PR and the required fuel pressure PRt. It is implemented (permitted) immediately on condition that the threshold is exceeded. As a result, a high drive current I can be easily secured against changes in the actual fuel pressure PR and the required fuel pressure PRt. For this reason, it is possible to prevent the fuel injection from being disabled due to the shortage of the drive current I against the fluctuation of the actual fuel pressure PR. The switching of the peak value of the drive current I from High to Low is performed (allowed) on condition that both the actual fuel pressure PR and the required fuel pressure PRt are lower than the second threshold value (which is smaller than the first threshold value). The Thus, the drive current I is lowered after confirming that both the actual fuel pressure PR and the required fuel pressure PRt have been reliably reduced. As a result, hunting of switching of the drive current I can be prevented. Further, it is possible to prevent the fuel injection from being disabled due to the shortage of the drive current I against the fluctuation of the actual fuel pressure PR.

  Further, according to the above routine, the lower limit value QMIN of the required fuel injection amount is changed so as to decrease as the peak value of the drive current I (target value It) decreases. If the current required fuel injection amount QINJ is smaller than the injection amount lower limit value QMIN, the current required fuel injection amount QINJ is the injection amount so that the actual fuel injection amount does not fall below the lower limit value QMIN. It is corrected to become the lower limit QMIN. Here, according to the processing in steps 504 to 508, the drive current I is changed to High even under a situation where only the required fuel pressure PRt of the required fuel pressure PRt and the actual fuel pressure PR exceeds the first threshold value. become. In this situation, since the actual fuel pressure PR is low, a small amount may be required as the fuel injection amount QINJ. However, since the drive current I is high, it is difficult to accurately inject fuel with such a small amount. According to the above routine, the lower limit value QMIN of the injection amount is made smaller as the peak value of the drive current I (target value It) becomes lower. Therefore, under this situation (that is, the drive current I is high, the required fuel injection amount QINJ can prevent the fuel injection with the required (minute) amount from being impossible under a small situation).

DESCRIPTION OF SYMBOLS 10 Internal combustion engine 12 Intake passage 14 Exhaust passage 16 Air cleaner 18 Air flow meter 20 Turbo supercharger 22 Intercooler 24 Throttle valve 26 Fuel injection valve 28 Delivery pipe 30 High pressure fuel pump 30a High pressure fuel pump inlet 30b High pressure fuel pump outlet 30c High-pressure fuel pump fuel pressurizing chamber 30d High-pressure fuel pump electromagnetic spill valve 30d1 Electromagnetic spill valve solenoid 30d2 Electromagnetic spill valve biasing spring 30e High-pressure fuel pump pressurizing cam 30f High-pressure fuel pump plunger 30g High-pressure fuel pump Pressure spring 30h Check valve 34 of high pressure fuel pump Fuel tank 36, 38 Fuel pipe 40 Cam shaft 50 ECU (Electronic Control Unit)
52 Fuel pressure sensor 54 A / F sensor 56 Crank angle sensor 58 Cooling water temperature sensor 60 Outside air temperature sensor 62 Spark plug 64 EDU (Electrical Driver Unit)

Claims (9)

A fuel injection valve for injecting fuel into a cylinder of the internal combustion engine;
A high-pressure fuel pump that pressurizes the fuel supplied to the fuel injection valve;
An electric drive unit for controlling the drive current of the fuel injection valve;
With
When the fuel pressure supplied to the fuel injection valve is high, the fuel supply control device for the internal combustion engine is set so that the peak value of the drive current of the fuel injection valve is higher than when the fuel pressure is low. There,
When the fuel pressure exceeds a predetermined pressure control range and excessively rises, the peak value of the drive current of the fuel injection valve is set to the maximum value within the predetermined current control range, or the excessive increase is recognized. A fuel supply control device for an internal combustion engine, wherein the fuel supply control device is higher than the value at the time of operation. The electric drive unit controls a drive current of the plurality of fuel injection valves,
2. The fuel supply control device for an internal combustion engine according to claim 1, wherein when the fuel pressure is excessively increased beyond the pressure control range, the start timing of fuel injection by the plurality of fuel injection valves is fixed.   The fuel injection by the fuel injection valve is prohibited when the engine speed is higher than a predetermined speed when the fuel pressure exceeds the pressure control range and rises excessively. A fuel supply control device for an internal combustion engine as described. The electric drive unit controls a drive current of the plurality of fuel injection valves,
When the fuel pressure is excessively increased beyond the pressure control range, the injection intervals of the plurality of fuel injection valves are prevented from becoming shorter than the limit injection interval that becomes the overheat limit of the electric drive unit. 3. The fuel supply control device for an internal combustion engine according to claim 1, wherein the injection time of the valve is limited.   When the injection time of the plurality of fuel injection valves is limited so that the injection interval of the plurality of fuel injection valves is not shorter than the limit injection interval, the air-fuel ratio under the limited injection time is predetermined. 5. The fuel supply control device for an internal combustion engine according to claim 4, wherein fuel injection by the fuel injection valve is prohibited when the value is leaner than a value.   The fuel injection valve is prohibited from injecting fuel divided into a plurality of times during one cycle of the internal combustion engine when the fuel pressure exceeds the pressure control range. The fuel supply control device for an internal combustion engine according to any one of 1 to 5.   When the outside air temperature is equal to or lower than a predetermined value, the peak value of the drive current of the fuel injection valve is set to a maximum value within a predetermined current control range until the engine coolant temperature reaches a predetermined value, and the required fuel The fuel supply control device for an internal combustion engine according to any one of claims 1 to 6, wherein the pressure is set to a maximum value within a predetermined pressure control range. As the fuel pressure increases, the peak value of the drive current of the fuel injection valve is set to increase stepwise in at least two steps,
When either one of the actual fuel pressure and the required fuel pressure exceeds a threshold value, the peak value of the drive current of the fuel injection valve is increased, while both the actual fuel pressure and the required fuel pressure exceed a predetermined threshold value. The fuel supply control device for an internal combustion engine according to any one of claims 1 to 7, wherein a peak value of a drive current of the fuel injection valve is lowered when the value is lower.   The control is performed such that when the peak value of the drive current of the fuel injection valve is low, the lower limit value of the required fuel injection amount is smaller than when the peak value is high. A fuel supply control device for an internal combustion engine according to claim 1.

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