JP2013092071A - Control device for internal combustion engine and internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately reduce variations in fuel injection amount among cylinders when lift duration of a plunger by any one of cam noses overlaps with an injection control period in any one of fuel injection valves.SOLUTION: An internal combustion engine including: a high-pressure pump pressurizing and discharging fuel, from a fuel tank, by lifting a plunger with three cam noses of a cam of an intake camshaft; and fuel injection valves provided for four corresponding cylinders and injecting and supplying fuel, fed under pressure from the high-pressure pump through a high-pressure passage, into the corresponding cylinders. Furthermore, an electronic control device controls a fuel injection mode by each fuel injection valve based on a fuel pressure Pr in the high-pressure passage in a period immediately before fuel injection. The control unit executes pressure feed limiting control in which, when lift duration of the plunger by any one of the cam noses overlaps with injection control duration in any one of the fuel injection valves, feeding fuel under pressure by the high-pressure pump during the lift duration is halted by opening a spill valve.

Description

  The present invention relates to an internal combustion engine that injects fuel pumped from a cam-driven high-pressure pump through a high-pressure passage into a cylinder through a fuel injection valve, and the fuel injection valve based on the fuel pressure in the high-pressure passage immediately before fuel injection. The present invention relates to a control device that controls the fuel injection mode.

  Conventionally, as this type of internal combustion engine control device, for example, there is a device described in Patent Document 1. In the conventional general internal combustion engine including the internal combustion engine described in Patent Document 1, the fuel stored in the fuel tank is sucked by the feed pump and supplied to the high pressure pump. Further, the fuel supplied to the high-pressure pump is further pressurized by the high-pressure pump and is pumped to a fuel injection valve provided for each cylinder through the high-pressure passage. The fuel thus pumped is injected into each cylinder from each fuel injection valve.

  The high-pressure pump is a cam-driven pump, and pressurizes the fuel supplied from the fuel tank by, for example, lifting a plunger provided in the cylinder by a cam nose of a cam provided on the intake camshaft.

When fuel is injected, the fuel injection mode such as the valve opening period of the fuel injection valve is controlled based on the fuel pressure in the high-pressure passage immediately before the fuel injection.
Here, conventionally, for example, a cam having two cam noses is employed in the case of a four-cylinder internal combustion engine, and a cam having three cam noses is employed in the case of a six-cylinder internal combustion engine. This is to reduce the fluctuation in fuel pressure immediately before fuel injection by performing fuel injection between a period during which the plunger is lifted by one cam nose (hereinafter referred to as a lift period) and the next lift period.

JP 2009-215909 A

  By the way, if a cam having three cam noses is adopted for a four-cylinder internal combustion engine, for example, as a cam for driving a high-pressure pump, the cam is shared between the four-cylinder internal combustion engine and the six-cylinder internal combustion engine. Will be able to. However, in this case, in a four-cylinder internal combustion engine, a situation occurs in which the plunger lift period due to the cam nose overlaps the period during which fuel pressure is detected for fuel injection and the period during which the fuel injection valve is opened. Therefore, excessive fuel is injected from the fuel injection valve, and the variation in the fuel injection amount among the cylinders cannot be ignored. As a result, the engine torque fluctuation increases, and the engine vibration may not be ignored.

  The present invention has been made in view of such circumstances, and its purpose is that the plunger lift period due to the cam nose overlaps the injection control period of the fuel injection valve, and the fuel injection amount varies between cylinders. It is an object to provide an internal combustion engine control apparatus and an internal combustion engine that can be accurately reduced.

Hereinafter, means for solving the above-described problems and the effects thereof will be described.
(1) The invention described in claim 1 is a high-pressure pump that pressurizes and discharges fuel supplied from a fuel tank by lifting a plunger by a plurality of cam noses of a cam that rotates as the engine output shaft rotates. The fuel injection valve is provided for each cylinder, and is applied to an internal combustion engine including a fuel injection valve that injects fuel that is pumped from the high-pressure pump through a high-pressure passage into the cylinder. In the internal combustion engine controller for controlling the fuel injection mode by the fuel injection valve based on the fuel pressure in the high pressure passage, the lift period when the lift period of the plunger by the cam nose overlaps the injection control period of the fuel injection valve The gist of the present invention is to execute the pressure limit control for limiting the fuel pressure by the high pressure pump.

  According to this configuration, when the lift period of the plunger due to the cam nose overlaps the injection control period in the fuel injection valve, that is, the period during which the fuel pressure is detected for fuel injection or during the opening period of the fuel injection valve. Thus, when the fuel pressure does not change in a desired manner, fuel pumping by the high-pressure pump during the lift period is restricted. For this reason, when the injection control period overlaps with the lift period, it is possible to prevent an excessive amount of fuel from being injected. Accordingly, the lift period of the plunger due to the cam nose overlaps with the injection control period of the fuel injection valve, and the variation in the fuel injection amount among the cylinders can be accurately reduced.

  (2) The gist of the invention described in claim 2 is that, in the internal combustion engine control device according to claim 1, fuel pumping by the high-pressure pump is stopped in the pressure feed restriction control. According to this configuration, fuel pumping by the high-pressure pump is stopped in the pumping restriction control. For this reason, it becomes possible to avoid that an excessive amount of fuel is injected when the injection control period overlaps the lift period of the plunger by the cam nose.

  (3) The invention according to claim 3 is the internal combustion engine controller according to claim 1 or 2, wherein the number of cylinders of the internal combustion engine is not a natural number times the number of the cam noses. Is the gist.

  According to this configuration, the lift period of the plunger due to the cam nose overlaps the injection control period in the fuel injection valve. Specifically, for example, a 4-cylinder internal combustion engine includes a cam having three cam noses, and a 6-cylinder internal combustion engine includes a cam having four cam noses. For this reason, for example, when a cam having three cam noses is employed, the application of the present invention to a four-cylinder internal combustion engine can accurately suppress the variation in the fuel injection amount between the cylinders. Further, conventional high-pressure pump control may be applied to a six-cylinder internal combustion engine. Therefore, it is possible to accurately suppress the variation in the fuel injection amount between the cylinders while adopting a common cam for the internal combustion engines having different numbers of cylinders.

  (4) In the invention according to any one of claims 1 to 3, as in the invention according to claim 4, in the pumping restriction control, among the lift periods of the plungers by the plurality of cam noses. This embodiment can be embodied in such a manner that the fuel pumping by the high-pressure pump is executed only in one lift period that does not overlap the injection control period in the fuel injection valve. In this case, if the fuel pumping amount in the one lift period is increased as compared with the size in the control configuration in which the fuel pumping is performed in all the lift periods during one rotation of the cam, the fuel is injected at each fuel injection. It can suppress suitably that deficiency.

  (5) In the invention according to any one of claims 1 to 3, as in the invention according to claim 5, each of the lift periods of the plunger by the plurality of cam noses is used in the pressure limit control. Of these, the embodiment can be embodied in such a manner that the fuel pumping by the high-pressure pump is limited only during the lift period that overlaps the injection control period of the fuel injection valve.

  (6) The invention according to claim 6 is the internal combustion engine control device according to any one of claims 1 to 5, and the gist thereof is that the pumping restriction control is executed during low load operation. Yes.

  If the variation in the fuel injection amount among the cylinders is large, the engine torque fluctuates and the engine vibration increases. In particular, engine vibration cannot be ignored during low-load operation of an internal combustion engine with a low engine vibration level. Therefore, if the present invention is applied during low load operation, the occurrence of such inconveniences can be suitably suppressed.

  Further, when the internal combustion engine is operated at a low load, the amount of fuel per injection by the fuel injection valve is small, so that the decrease in the fuel pressure per injection is small. For this reason, even if it becomes impossible to temporarily increase the fuel pressure by restricting the fuel pumping due to the application of the present invention, the occurrence of inconvenience such as a shortage of fuel to be injected is suppressed as much as possible. Will be able to.

(7) The invention according to claim 7 is the internal combustion engine control apparatus according to claim 6, wherein the pressure limit control is executed during idle operation.
When the internal combustion engine is idling, the driver is likely to feel uncomfortable due to engine vibration. In this regard, according to the invention described in claim 7, since the pressure limit control is executed during the idling operation, it is possible to suitably suppress the occurrence of engine vibration during the idling operation.

  (8) The invention according to claim 8 is a high-pressure pump that pressurizes and discharges fuel supplied from a fuel tank by a plunger being lifted by a plurality of cam noses of a cam that rotates as the engine output shaft rotates. An internal combustion engine provided with a fuel injection valve provided for each cylinder and supplying fuel injected from the high-pressure pump through a high-pressure passage into the cylinder. The number of cylinders of the internal combustion engine is that of the cam nose. When the lift period of the plunger due to the cam nose overlaps the injection control period of the fuel injection valve, the fuel compressed by the plunger in the lift period is transferred to the fuel tank. The gist of the invention is to provide a discharge mechanism that discharges toward the end.

  According to this configuration, when the lift period of the plunger by the cam nose overlaps the injection control period in the fuel injection valve, the fuel compressed by the plunger is discharged toward the fuel tank through the discharge mechanism. As a result, fuel pumping by the high-pressure pump during the lift period is limited. For this reason, when the injection control period overlaps with the lift period, it is possible to prevent an excessive amount of fuel from being injected. Accordingly, the lift period of the plunger due to the cam nose overlaps with the injection control period of the fuel injection valve, and the variation in the fuel injection amount among the cylinders can be accurately reduced.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows schematic structure of the fuel supply system in an internal combustion engine about the internal combustion engine control apparatus and internal combustion engine which concern on one Embodiment of this invention. The flowchart which shows the process sequence of the drive control of the high pressure pump in the embodiment. It is a timing chart for demonstrating the effect | action in the embodiment, (a) Transition of the injection state of each fuel injection valve, (b) Transition of the pumping state of the high-pressure pump at the time of idle operation, (c) At the time of idle operation 9 is a timing chart showing together the transition of fuel pressure in (d), transition of pumping state of a high-pressure pump in a comparative example, and (e) transition of fuel pressure in a comparative example.

  Hereinafter, an embodiment in which an internal combustion engine and an internal combustion engine control device according to the present invention are embodied as an in-cylinder in-line four-cylinder internal combustion engine and its control device will be described with reference to FIGS.

FIG. 1 shows a schematic configuration of a fuel supply system in the internal combustion engine of the present embodiment.
As shown in FIG. 1, in the fuel supply system of the internal combustion engine 1, an electric feed pump 3 is disposed in a fuel tank 2, and a low pressure supply pipe 4 is connected to the feed pump 3. The fuel stored in the fuel tank 2 is sucked by the feed pump 3, pressurized to a predetermined feed pressure (for example, several hundred kPa), and pumped to the low pressure supply pipe 4. Incidentally, the feed pump 3 is a pump capable of changing the fuel discharge amount. A return pipe 5 is branched and connected in the middle of the low-pressure supply pipe 4. A pressure regulating valve 6 is provided in the middle of the return pipe 5, and the pressure regulating valve 6 is opened when the fuel pressure in the low pressure supply pipe 4 becomes equal to or higher than the feed pressure. Thereby, a part of the fuel discharged from the feed pump 3 is returned to the fuel tank 2 through the return pipe 5, and the pressure of the fuel in the low pressure supply pipe 4 is maintained at the feed pressure.

A high pressure pump 10 is connected to the downstream side of the low pressure supply pipe 4.
In the pump housing 11 of the high-pressure pump 10, a suction passage 12 connected to the downstream side of the low-pressure supply pipe 4, a cylinder 13 connected to the downstream side of the suction passage 12, and a downstream side of the cylinder 13 are connected. A discharge passage 14 is formed.

  A suction port 21 for sucking low-pressure fuel from the feed pump 3 is formed at an upstream end portion (upper end portion in FIG. 1) of the cylinder 13. A discharge port 22 for discharging fuel toward the discharge passage 14 is formed on the side surface of the cylinder 13 (the right side surface in FIG. 1). A plunger 15 is provided in the cylinder 13 so as to reciprocate. A pressure chamber 16 is defined by the inner wall of the cylinder 13 and the top surface of the plunger 15. The discharge port 22 communicates with the pressure chamber 16.

  A valve body 23 of a spill valve 20 that opens and closes the suction port 21 is accommodated in the cylinder 13. The valve body 23 is provided so as to be movable along the axial direction of the cylinder 13 via a needle 23a. The spill valve 20 is a so-called normally open valve, and is always urged in a direction to open the suction port 21 by the urging force of the spring 25. The spill valve 20 is sucked in a direction to close the suction port 21 by energizing the solenoid 24.

  The plunger 15 is driven by rotation of a crankshaft (not shown) that is an engine output shaft. Specifically, the intake camshaft 31 rotates as the crankshaft rotates, and the plunger 15 reciprocates in the cylinder 13 by being lifted by a cam 32 provided on the intake camshaft 31. The cam 32 has three cam noses 32a protruding in the radial direction from the base circle 32b. These cam noses 32a have the same shape, and are provided at equal angular intervals in the circumferential direction. A lifter 17 is provided below the plunger 15, and the lifter 17 is maintained in contact with the cam surface of the cam 32 by the urging force of the spring 18.

  In the high-pressure pump 10, when energization to the solenoid 24 is stopped when the plunger 15 descends and the volume of the pressure chamber 16 increases, the suction port 21 is opened and fuel is sucked into the pressure chamber 16 from the suction passage 12. The

  Further, when the solenoid 15 is energized when the plunger 15 rises and the volume of the pressure chamber 16 decreases, the suction port 21 is closed, the fuel in the pressure chamber 16 is pressurized, and the discharge port 22 passes through the discharge passage 14. Discharged.

Furthermore, the amount of fuel sucked into the pressure chamber 16 can be adjusted by adjusting the energization period of the solenoid 24, that is, the period during which the suction port 21 is closed.
A discharge valve 19 is provided in the middle of the discharge passage 14. When the pressure of the fuel acting on the discharge valve 19 from the pressure chamber 16 side becomes equal to or higher than a predetermined discharge pressure, the discharge valve 19 is opened. As a result, the fuel is allowed to be pumped to the fuel injection valve 9 side.

Further, a relief passage 26 is formed in the discharge passage 14 so as to bypass the discharge valve 19, and an orifice portion 27 is provided in the middle of the relief passage 26.
A high pressure supply pipe 7 is connected to the pump housing 11 on the downstream side of the discharge passage 14, and a delivery pipe 8 is connected to the downstream side of the high pressure supply pipe 7. A fuel injection valve 9 for injecting and supplying fuel into each cylinder is connected to the delivery pipe 8. The drive control of the fuel injection valve 9 is performed by the electronic control unit 40.

  Various controls of the internal combustion engine 1 are performed by the electronic control unit 40. The electronic control unit 40 temporarily stores a central processing unit (CPU) that performs arithmetic processing related to various controls, a read-only memory (ROM) that stores various control programs and data, and results of arithmetic processing. It comprises a random access memory (RAM) for storing. Then, the electronic control unit 40 reads detection signals from various sensors, executes various arithmetic processes, and comprehensively controls the internal combustion engine 1 based on the results.

  Various sensors include a crank angle sensor that detects the rotational phase of the crankshaft, a cam angle sensor that detects the rotational phase of the intake camshaft, an air flow meter that detects the intake air amount, a throttle sensor that detects the throttle opening, and engine cooling. A water temperature sensor for detecting the temperature of the water is provided. A fuel pressure sensor 41 that detects the fuel pressure Pr in the delivery pipe 8 is also provided. In addition, an accelerator sensor that detects an accelerator operation amount, a brake sensor that detects a brake operation amount, a vehicle speed sensor that detects a vehicle speed that is the traveling speed of the vehicle, and the like are provided. These various sensors are electrically connected to the electronic control device 40.

  The electronic control unit 40 controls the injection mode such as the valve opening period of the fuel injection valve 9 based on the fuel pressure Pr in the delivery pipe 8 immediately before the fuel injection. That is, if the valve opening period of the fuel injection valve 9 is constant, the amount of fuel actually injected from the fuel injection valve 9 increases as the fuel pressure Pr in the delivery pipe 8 increases. For this reason, the higher the fuel pressure Pr in the delivery pipe 8 is, the shorter the valve opening period of the fuel injection valve 9 is set so that the set fuel injection amount is injected.

  In the present embodiment, the cam 32 having three cam noses 32a is provided for the four-cylinder internal combustion engine 1, so that the cam 32 used in the six-cylinder internal combustion engine can be used. ing. That is, the cam 32 is shared by the 4-cylinder internal combustion engine 1 and the 6-cylinder internal combustion engine.

  However, in this case, as described above, in the four-cylinder internal combustion engine 1, a period for detecting the fuel pressure Pr for fuel injection or a period for opening the fuel injection valve 9 (hereinafter referred to as injection control in the fuel injection valve 9). The period during which the lift period of the plunger 15 by the cam nose 32a of the cam 32 (hereinafter simply referred to as the lift period) overlaps. Here, the lift period is a period in which the volume of the pressure chamber 16 is reduced due to the plunger 15 being lifted, and the fuel in the pressure chamber 16 is energized when the solenoid 24 is energized during the lift period. Is a period during which the gas is discharged into the discharge passage 14. For this reason, excessive fuel is injected from the fuel injection valve 9, and variations in the fuel injection amount among the cylinders cannot be ignored. As a result, the engine torque fluctuations become large, and there is a possibility that the engine vibration cannot be ignored particularly during idling with a low engine vibration level.

  Therefore, in the present embodiment, when the lift period overlaps the injection control period in the fuel injection valve 9 through the electronic control unit 40, the spill valve 20 is opened so that the fuel is pumped by the high-pressure pump 10 during the lift period. The pumping limit control to stop is executed. Specifically, in this pressure feed restriction control, fuel pressure feed by the high pressure pump 10 is executed only in one lift period that does not overlap the injection control period in the fuel injection valve 9 among the three lift periods during one rotation of the cam 32. Like to do. Thereby, the occurrence of the above-described inconvenience is suppressed.

  Next, with reference to FIG. 2, drive control of the high-pressure pump 10 in this embodiment will be described. FIG. 2 shows a processing procedure for drive control of the high-pressure pump 10. This series of processing is repeatedly executed every time the predetermined crank angle (° CA) is reached during engine operation.

  As shown in FIG. 2, in this series of processes, first, in step S1, it is determined whether or not the internal combustion engine 1 is in an idle operation state. If it is determined that the engine is not in the idle operation state (step S1: “NO”), the process proceeds to step S2, and all the lift periods during one rotation of the cam 32 (in this case, three lifts). The driving duty of the spill valve 20 is calculated so as to perform fuel pumping during the period. Then, the process proceeds to step S6, and energization control to the solenoid 24 is performed based on the calculated drive duty. Then, this series of processes is temporarily terminated.

  On the other hand, if it is determined in step S1 that the engine is in the idle operation state (step S1: “YES”), the process proceeds to step S3. In step S3, it is determined whether or not the fuel pressure Pr is the target fuel pressure. Here, the target fuel pressure is performed at the latest timing after the fuel pumping is performed when the fuel pumping is performed by the high-pressure pump 10 only during the one lift period during one rotation of the cam 32. In the fuel injection, the fuel pressure required for the fuel injection is set so as to be secured, and is set in advance through experiments and the like. Here, when it is determined that the fuel pressure Pr is not the target fuel pressure (step S3: “NO”), the process proceeds to step S2 and step S6 in order, and energization control to the solenoid 24 is performed. This series of processes is temporarily terminated.

  On the other hand, when it is determined in step S3 that the fuel pressure Pr is the target fuel pressure (step S3: “YES”), the process proceeds to step S4. In step S4, a lift period for stopping fuel pumping (hereinafter referred to as a pumping stop lift period) is derived. Then, the process proceeds to step S5, and the drive duty of the spill valve 20 is calculated so that the fuel pumping is stopped in the derived pumping stop lift period and the fuel pumping is performed in the other lift periods. Then, the process proceeds to step S6, energization control to the solenoid 24 is performed, and this series of processes is temporarily ended.

  Next, with reference to FIG. 3, the operation in this embodiment will be described. FIG. 3 also shows (a) the transition of the injection state of each fuel injection valve, (b) the transition of the pumping state of the high-pressure pump 10 during idle operation, and (c) the transition of the fuel pressure Pr during idle operation. Show. FIG. 3 also shows (d) the transition of the pumping state of the high-pressure pump 10 in the comparative example, and (e) the transition of the fuel pressure Pr in the comparative example. In FIG. 3, the horizontal axis is the crank angle (° CA).

  As shown to Fig.3 (a), since the internal combustion engine 1 of this embodiment has four cylinders, the fuel injection by each fuel injection valve is performed by the 180 degree CA space | interval. That is, in this case, the fuel injection of the fourth cylinder (# 4) is performed at 30 ° CA, and the fuel injection of the second cylinder (# 2) is performed at 210 ° CA. Further, the fuel injection of the first cylinder (# 1) is performed at 390 ° CA, and the fuel injection of the third cylinder (# 3) is performed at 570 ° CA.

  Here, in the comparative example, fuel pumping is performed in all lift periods during one rotation of the cam 32. Therefore, as shown in FIGS. 3D and 3E, a period from about −30 ° CA (690 ° CA) to 0 ° CA, a period from about 210 ° CA to 240 ° CA, about 450 Fuel pumping is performed through the spill valve 20 being closed in each of the periods from ° CA to 480 ° CA.

  Here, as shown in FIG. 3 (e), during the period from about −30 ° CA (690 ° CA) to 0 ° CA, fuel pressure Pr rises due to fuel pumping, and thereafter 30 When the fuel injection valve 9 is opened at ° CA, the fuel pressure Pr decreases.

  On the other hand, during a period from about 210 ° CA to 240 ° CA, the lift period (in this case, also the pressure feeding period) and the injection control period in the fuel injection valve 9 (the detection period of the fuel pressure Pr, the opening of the fuel injection valve 9). 3), the fuel pressure Pr rises despite the fuel injection valve 9 being opened, as shown in FIG. Accordingly, excessive fuel is injected from the fuel injection valve 9.

  Further, when the fuel injection valve 9 is opened at the subsequent 390 ° CA, the fuel pressure Pr decreases. The fuel pressure Pr is increased by performing fuel pumping in a period from about 450 ° CA to 480 ° CA, and the fuel pressure Pr is decreased by opening the fuel injection valve 9 at 570 ° CA thereafter. To come.

  In contrast, in the present embodiment, as shown in FIGS. 3B and 3C, the spill valve 20 is closed only during a period from about −90 ° CA to 0 ° CA. Fuel pumping is performed. As a result, the fuel pressure Pr increases, and the fuel pressure Pr decreases as the fuel injection valve 9 is opened at 30 ° CA thereafter.

  On the other hand, in the period from about 210 ° CA to 240 ° CA, unlike the previous comparative example, the fuel compressed by the plunger 15 by opening the spill valve 20 is directed to the fuel tank 2 through the inlet 21. Will be discharged. As described above, when the lift period overlaps the injection control period in the fuel injection valve 9, that is, in the period in which the fuel pressure Pr is detected for fuel injection or in the valve opening period of the fuel injection valve 9, the plunger 15 is lifted. When the fuel pressure Pr does not change in a desired manner, fuel pumping by the high pressure pump 10 during the lift period is stopped. For this reason, it becomes possible to avoid an excessive amount of fuel being injected when the injection control period overlaps the lift period.

  Further, during the period from about 450 ° CA to 480 ° CA in which the fuel pumping is performed in the previous comparative example, the fuel pumping is stopped through the drive control of the spill valve 20. In the present embodiment, a period (a period from about −90 ° CA to 0 ° CA) in which the spill valve 20 is closed to perform fuel pumping is a period (about −30 ° CA (690 ° CA) in the previous comparative example. ) To 0 ° CA), which is about 3 times. This is because the amount of fuel pumped by one fuel pumping is increased to suitably suppress the shortage of fuel during each subsequent fuel injection.

In addition, the spill valve 20 in this embodiment corresponds to the discharge mechanism according to the present invention.
According to the internal combustion engine control device and the internal combustion engine according to the present embodiment described above, the following operational effects can be obtained.

  (1) The internal combustion engine 1 includes a high-pressure pump 10 that pressurizes and discharges fuel supplied from the fuel tank 2 by lifting the plunger 15 by three cam noses 32 a of the cam 32 of the intake camshaft 31. The internal combustion engine 1 is a fuel injection valve 9 provided for each of the four cylinders. The fuel that is pumped from the high-pressure pump 10 through the high-pressure passages (the discharge passage 14, the high-pressure supply pipe 7, and the delivery pipe 8) A fuel injection valve 9 is provided for injection into the cylinder. That is, the number of cylinders “4” of the internal combustion engine 1 is not a natural number multiple of the number “3” of the cam noses 32a. The electronic control unit 40 controls the fuel injection mode by the fuel injection valve 9 based on the fuel pressure Pr in the delivery pipe 8 immediately before the fuel injection. Then, when the lift period of the plunger 15 by the cam 32 overlaps with the injection control period in the fuel injection valve 9 through the electronic control unit 40, the spill valve 20 is opened so that the fuel is pumped by the high pressure pump 10 in the lift period. The pumping restriction control is stopped to stop the operation. Specifically, in the pressure feed restriction control, the fuel pressure feed by the high pressure pump 10 is executed only in one lift period that does not overlap the injection control period of the fuel injection valve 9 among the lift periods of the plunger 15 by the three cam noses 32a. I have to.

  According to such a configuration, the lift period of the plunger 15 by the cam 32 overlaps with the injection control period in the fuel injection valve 9, and the variation in the fuel injection amount among the cylinders can be accurately reduced. .

  Further, according to the above configuration, even when the cam 32 having the three cam noses 32a is employed in the four-cylinder internal combustion engine 1, it is possible to accurately suppress the fuel injection amount from varying between the cylinders. Further, when a cam 32 having three cam noses 32a is employed in a 6-cylinder internal combustion engine, conventional high-pressure pump control may be applied. For these reasons, it is possible to accurately suppress the variation in the fuel injection amount between the cylinders while adopting the common cam 32 for the internal combustion engines having different numbers of cylinders.

(2) The electronic control unit 40 is configured to execute the pressure limit control during idle operation.
If the variation in the fuel injection amount among the cylinders is large, the engine torque fluctuates and the engine vibration increases. The engine vibration cannot be ignored particularly during the idling operation of the internal combustion engine 1 having a low engine vibration level. Therefore, the occurrence of such inconveniences can be suitably suppressed by executing the above-described pressure feed restriction control during idle operation.

  Further, during the idling operation of the internal combustion engine 1, the amount of fuel per injection by the fuel injection valve 9 is small, so the amount of decrease in fuel pressure per injection is small. For this reason, even if it becomes impossible to temporarily increase the fuel pressure by limiting the fuel pumping with the execution of the pressure limiting control, it is possible to suppress the occurrence of inconvenience such as a shortage of the fuel injected thereby. Will be able to.

  Note that the internal combustion engine control device and the internal combustion engine according to the present invention are not limited to the configurations exemplified in the above-described embodiment, and can be implemented as, for example, the following forms appropriately modified.

In the above-described embodiment, the above-described pressure-feeding restriction control is executed during idle operation. However, this may be executed during low-load operation other than during idle operation.
In the above-described embodiment, the fuel pressure feeding by the high-pressure pump 10 is executed only in one lift period that does not overlap the injection control period in the fuel injection valve 9 among the lift periods of the plunger 15 by the three cam noses 32a. However, the execution mode of the pressure limit control according to the present invention is not limited to this, and the lift period overlapping the injection control period in the fuel injection valve 9 among the lift periods of the plunger 15 by the three cam noses 32a (previous implementation) In the embodiment, fuel pumping by the high-pressure pump 10 may be limited only during a period from about 210 ° CA to 240 ° CA.

  In the above embodiment, the four-cylinder internal combustion engine 1 is illustrated as having the cam 32 having the three cam noses 32a, but the internal combustion engine according to the present invention is not limited to this. In addition, for example, a 6-cylinder internal combustion engine may include a cam having four cam noses. In this case, the number of cylinders “6” of the internal combustion engine is not a natural number multiple of the number of cam noses “4”, and the plunger lift period due to the cam nose overlaps the injection control period of the fuel injection valve. Therefore, by applying the present invention to such an internal combustion engine, it is possible to accurately suppress the fuel injection amount from varying between the cylinders.

  In the above-described embodiment, the pumping limit control is exemplified for stopping the fuel pumping by the high-pressure pump 10, but the pumping limit control according to the present invention is not necessarily limited to stopping the fuel pumping. That is, if the lift period overlaps with the injection control period in the fuel injection valve, the fuel pumping is limited, for example, by reducing the fuel pumping amount by the high-pressure pump as compared with the case where the lift period does not overlap with the injection control period. Good.

  DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine, 2 ... Fuel tank, 3 ... Feed pump, 4 ... Low pressure supply pipe (low pressure passage), 5 ... Return pipe, 6 ... Pressure regulating valve, 7 ... High pressure supply pipe (high pressure passage), 8 ... Delivery pipe ( High pressure passage), 9 ... Fuel injection valve, 10 ... High pressure pump, 11 ... Pump housing, 12 ... Suction passage (low pressure passage), 13 ... Cylinder, 14 ... Discharge passage (high pressure passage), 15 ... Plunger, 16 ... Pressure chamber , 17 ... Lifter, 18 ... Spring, 19 ... Discharge valve, 20 ... Spill valve, 21 ... Suction port, 22 ... Discharge port, 23 ... Valve body, 23a ... Needle, 24 ... Solenoid, 25 ... Spring, 26 ... Relief passage , 27 ... Orifice part, 31 ... Intake camshaft, 32 ... Cam, 32a ... Cam nose, 40 ... Electronic control unit, 41 ... Fuel pressure sensor.

Claims (8)

A high-pressure pump that pressurizes and discharges fuel supplied from a fuel tank by lifting a plunger by a plurality of cam noses of a cam that rotates as the engine output shaft rotates, and a fuel injection valve provided for each cylinder. The fuel injection valve is applied to an internal combustion engine that includes a fuel injection valve that injects fuel supplied from the high-pressure pump through a high-pressure passage into the cylinder, and based on the fuel pressure in the high-pressure passage immediately before fuel injection. In the internal combustion engine controller for controlling the fuel injection mode by
An internal combustion engine control device that executes pressure limit control that limits fuel pumping by the high pressure pump during the lift period when a lift period of the plunger by the cam nose overlaps an injection control period of the fuel injection valve . The internal combustion engine control apparatus according to claim 1,
The internal combustion engine control device according to claim 1, wherein in the pressure feed restriction control, fuel pressure feed by the high pressure pump is stopped. The internal combustion engine control device according to claim 1 or 2,
The internal combustion engine control apparatus, wherein the number of cylinders of the internal combustion engine is not a natural number times the number of the cam noses. In the internal combustion engine control device according to any one of claims 1 to 3,
In the pressure feed restriction control, the fuel pressure feed by the high pressure pump is executed only in one lift period that does not overlap the injection control period in the fuel injection valve among the lift periods of the plunger by the plurality of cam noses. Engine control device. In the internal combustion engine control device according to any one of claims 1 to 3,
The internal combustion engine controller according to claim 1, wherein the pumping restriction control restricts fuel pumping by the high-pressure pump only during a lift period that overlaps an injection control period of the fuel injection valve among the lift periods of the plunger by the plurality of cam noses. . In the internal combustion engine control device according to any one of claims 1 to 5,
The internal combustion engine controller according to claim 1, wherein the pressure limit control is executed during low load operation. The internal combustion engine control apparatus according to claim 6,
The internal combustion engine controller according to claim 1, wherein the pressure feed restriction control is executed during idle operation. A high-pressure pump that pressurizes and discharges the fuel supplied from the fuel tank by causing the plunger to lift by a plurality of cam noses of the cam rotating as the engine output shaft rotates;
An internal combustion engine comprising a fuel injection valve provided for each cylinder and a fuel injection valve that injects fuel supplied from the high-pressure pump through a high-pressure passage into the cylinder.
The number of cylinders of the internal combustion engine is not a natural number times the number of the cam noses,
When the lift period of the plunger by the cam nose overlaps with the injection control period of the fuel injection valve, a discharge mechanism is provided that discharges the fuel compressed by the plunger during the lift period toward the fuel tank. Internal combustion engine.

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