JP6329092B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine.

  In a cylinder injection type internal combustion engine, as described in Japanese Patent Application Laid-Open No. 2013-155642 (Patent Document 1), a cam mechanism driven by the internal combustion engine is used to apply a biasing force of a spring pressing the tappet against the cam. Mechanical fuel pumps are used that lift the plunger against it.

JP 2013-155642 A

  In conventional fuel pumps, the lift amount of the plunger by the cam mechanism is constant, so the load of the cam mechanism that lifts the plunger against the biasing force of the spring (mechanical friction) regardless of the fuel pressure required by the internal combustion engine. Was almost constant. For this reason, in the fuel pump, there are operation regions where mechanical friction is larger than necessary, such as an operation region where the required fuel pressure is low, and it has been difficult to improve fuel consumption.

  Therefore, an object of the present invention is to provide a control device for an internal combustion engine that can reduce mechanical friction of a fuel pump.

The internal combustion engine uses a fuel injection valve that directly injects fuel into the cylinder and a cam mechanism that is driven by the internal combustion engine to lift the plunger according to the urging force of the spring, thereby reducing the volume of the pressurizing chamber. the boosts having a fuel pump for supplying the fuel injection valve, a variable mechanism for changing a lift amount of the plunger, the intake valve for pressurizing regulating the pressure of fuel flowing into the pressure chamber, the. The control device for the internal combustion engine minimizes the lift amount of the plunger by the variable mechanism when the pressure of the fuel supplied from the fuel pump to the fuel injection valve is less than a predetermined value, and when the fuel pressure is equal to or higher than the predetermined value , the lift amount of the plunger by variable mechanism to change in accordance with the pressure of the fuel, when the fuel pressure is changed by changing the lift amount, adjusts the opening of the suction valve.

  According to the present invention, mechanical friction of the fuel pump can be reduced.

It is a schematic diagram showing an example of a fuel injection system, It is sectional drawing which shows the outline | summary of 1st Example of a variable mechanism. It is explanatory drawing of the method of increasing the lift amount of a plunger. It is explanatory drawing of the method to reduce the lift amount of a plunger. It is explanatory drawing of the method of hold | maintaining the lift amount of a plunger. It is explanatory drawing of an effect | action at the time of making the lift amount of a plunger the minimum. It is explanatory drawing of an effect | action at the time of maximizing the lift amount of a plunger. It is a perspective view which shows 2nd Example of a variable mechanism. It is a side view which shows 2nd Example of a variable mechanism. It is explanatory drawing of an effect | action at the time of making the lift amount of a plunger the minimum. It is explanatory drawing of an effect | action at the time of maximizing the lift amount of a plunger. It is a block diagram which shows an example of the internal structure of a fuel pump control apparatus. It is a flowchart which shows an example of the fuel pressure control of a high pressure fuel pump. It is explanatory drawing of the predetermined value which fixes the area | region which fixes and act | operates a variable mechanism. It is explanatory drawing which shows an example of the method of setting a predetermined value. It is a flowchart which shows the other example of the fuel pressure control of a high pressure fuel pump. It is explanatory drawing which shows the control state of a variable mechanism.

Hereinafter, embodiments for carrying out the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an example of a fuel injection system that directly injects fuel into a cylinder of an internal combustion engine.

  An electronically controlled fuel injection valve 200 that directly injects fuel into each cylinder of the cylinder block 120 is attached to the cylinder head 110 of the internal combustion engine 100 mounted on the automobile. In response to an operation signal from the outside, the fuel injection valve 200 lifts a plunger biased in the valve closing direction by a spring, thereby injecting fuel into the cylinder from the nozzle hole at the tip. Here, as the internal combustion engine 100, for example, an in-line four-cylinder in-cylinder gasoline engine or a diesel engine can be used.

  A feed pump (low-pressure fuel pump) 400 that sucks fuel from the bottom and pressure-feeds the fuel tank 300 for storing fuel is attached. A fuel discharge port 410 of the feed pump 400 is connected to a fuel supply port 600A of a high-pressure fuel pump 600 that boosts the fuel to a predetermined pressure via a low-pressure fuel pipe 500. The fuel discharge port 600B of the high-pressure fuel pump 600 communicates with the fuel supply port 210 of each fuel injection valve 200 via a high-pressure fuel pipe 520 that branches into a plurality of portions on the way.

  Therefore, the fuel stored in the fuel tank 300 is sucked up by the feed pump 400 and supplied to the high-pressure fuel pump 600 through the low-pressure fuel pipe 500. The fuel supplied to the high-pressure fuel pump 600 is boosted to a predetermined pressure and then supplied to each fuel injection valve 200 through the high-pressure fuel pipe 520. The high-pressure fuel pump 600 is an example of a fuel pump.

Here, an example of the high-pressure fuel pump 600 will be described.
Inside the pump body 610, a low-pressure damper 610A that smoothes the pulsation of fuel supplied from the feed pump 400, a cylinder 610B in which a plunger 620 is reciprocably fitted, and a pressurizing chamber 610C that pressurizes the fuel. Are formed respectively. An intake valve having a spring 630A and a valve body 630B that opens only in a direction in which fuel flows from the low pressure damper 610A to the pressurizing chamber 610C, in the low pressure fuel passage 610D that communicates the low pressure damper 610A and the pressurizing chamber 610C. 630 is disposed.

  Further, the suction valve 630 is provided with a solenoid actuator 640 that forcibly opens the valve body 630B against the urging force of the spring 630A. The high-pressure fuel passage 610E that connects the pressurizing chamber 610C and the fuel discharge port 600B has a spring 650A and a valve body 650B that opens only in the direction in which the fuel flows from the pressurization chamber 610C to the fuel discharge port 600B. A discharge valve 650 is provided.

  At the lower end of the plunger 620, that is, at the end opposite to the pressurizing chamber 610C, the rotational motion of the cam mechanism 660 driven by the rotational force of the crankshaft, camshaft, etc. of the internal combustion engine 100 is converted into linear motion. A tappet 670 is attached. The tappet 670 is pressed against the cam 660A by a spring 680 such as a compression coil spring so as to come into contact with the cam 660A of the cam mechanism 660.

  Therefore, when the cam 660A of the cam mechanism 660 rotates, the rotational motion is converted into a linear motion by the tappet 670, and the plunger 620 reciprocates. When the plunger 620 descends, the volume of the pressurizing chamber 610C increases, so the fuel pressure in the pressurizing chamber 610C decreases and the intake valve 630 opens, and fuel flows from the low pressure damper 610A into the pressurizing chamber 610C. On the other hand, when the plunger 620 is raised, the volume of the pressurizing chamber 610C is decreased, so that the fuel pressure in the pressurizing chamber 610C is increased, the intake valve 630 is closed, and the discharge valve 650 is opened. When the discharge valve 650 is opened, the fuel in the pressurizing chamber 610C is discharged from the fuel discharge port 600B through the high-pressure fuel passage 610E.

  If the intake valve 630 is opened when the plunger 620 is raised, the fuel that has flowed into the pressure chamber 610C when the plunger 620 is lowered passes from the pressure chamber 610C to the low pressure damper 610A (suction side) via the low pressure fuel passage 610D. Is returned. Therefore, by changing the valve closing timing of the intake valve 630 when the plunger 620 is raised by the solenoid actuator 640, the ratio of the fuel returned to the intake side and the fuel to be boosted is changed. The fuel pressure of the discharged fuel can be adjusted. Here, the suction valve 630 and the solenoid actuator 640 are cited as examples of the pressure adjusting mechanism.

  Further, the low pressure damper 610A and the high pressure fuel passage 610E downstream of the discharge valve 650 are opened only in the direction in which fuel flows out from the high pressure fuel passage 610E to the low pressure damper 610A, and a relief valve having a spring 690A and a valve body 690B. 690 communicates.

  Therefore, by appropriately setting the valve opening characteristics of the relief valve 690, when the fuel pressure in the high pressure fuel passage 610E exceeds a specified value, the valve body 690B moves against the urging force of the spring 690A, and the pressure from the high pressure fuel passage 610E. The fuel flows out to the low pressure damper 610A. For this reason, the fuel pressure discharged from the high-pressure fuel pump 600 is limited to a specified value or less, and, for example, piping located downstream of the high-pressure fuel pump 600 can be protected.

  Further, a variable mechanism 700 that changes the lift amount of the plunger 620 is attached to the high-pressure fuel pump 600.

FIG. 2 shows a first embodiment of the variable mechanism 700.
The plunger 620 includes a first structure 622 that faces the pressurizing chamber 610C, a second structure 624 that sits on the tappet 670, and a base end (lower end) that can be relatively displaced in the axial direction. It is divided into two. The first structure body 622 is provided with a hydraulic pressure, which is an example of hydraulic oil, and moves the first structure body 622 away from the second structure body 624 in a direction away from the first structure body 622. A working chamber 622A is formed. Further, in the second structure body 624, a ring-shaped second working chamber that receives supply of hydraulic pressure and moves the first structure body 622 in the direction of approaching the second structure body 624. 624A is formed. Here, the first working chamber 622A and the second working chamber 624A are formed in a shape such that the pressure receiving areas of the first structure body 622 are equal.

  Therefore, as shown in FIG. 3, when hydraulic pressure is supplied to the first working chamber 622A, the first structure 622 moves away from the second structure 624, and the lift amount of the plunger 620 is increased. Can be increased. In addition, as shown in FIG. 4, when hydraulic pressure is supplied to the second working chamber 624A, the first structure 622 moves toward the second structure 624 and the lift amount of the plunger 620 is increased. Can be reduced. In order to maintain the lift amount of the plunger 620, as shown in FIG. 5, when the hydraulic pressure is supplied to the first working chamber 622A and the second working chamber 624A, the plunger 620 is moved upward and downward in the drawing. The force to move to the balance can be balanced and the position can be maintained.

  Therefore, when the cam mechanism 660 is driven while the lift amount of the plunger 620 is minimized, as shown in FIG. 6, the stroke amount of the plunger 620 is minimized, the pushing amount for pushing the spring 680 is minimized, and mechanical friction is obtained. Can be reduced. As the cam mechanism 660 is driven, as shown in FIG. 7, the lift amount of the plunger 620 is maximized at the end of the fuel discharge stroke (top dead center), and the plunger at the start of the fuel discharge stroke (bottom dead center). When the lift amount of 620 is minimized, the stroke amount of the plunger 620 is maximized. And since the stroke amount of the plunger 620 becomes the maximum, the fuel pressure discharged from the high pressure fuel pump 600 can be maximized. Note that the fuel pressure discharged from the high-pressure fuel pump 600 can be arbitrarily changed by changing the lift amount of the plunger 620 at the top dead center from the minimum to the maximum.

8 and 9 show a second embodiment of the variable mechanism 700. FIG.
The variable mechanism 700 includes a drive shaft 710 that rotates in conjunction with the crankshaft of the internal combustion engine 100, a peristaltic cam 720 that is rotatably mounted on the outer periphery of the drive shaft 710, and an eccentric that is fixed to the outer periphery of the drive shaft 710. A cam 730, a ring-shaped link 740 that is externally fitted to the eccentric cam 730, a control shaft 750 that is disposed substantially parallel to the drive shaft 710, and a control cam that is eccentrically fixed to the outer periphery of the control shaft 750 760, a rocker arm 770 that is fitted to the control cam 760 so as to be relatively rotatable and has one end connected to the ring-shaped link 740, and a rod-like link 780 that connects the other end of the rocker arm 770 and the swing cam 720. Have. When the control shaft 750 is rotated via the gear train 792 by a motor 790 such as a brushless motor, the rocking center of the rocker arm 770 changes according to the rotation angle. When the rocking center of the rocker arm 770 changes, the lift amount of the plunger 620 reciprocated by the rocking cam 720 can be changed.

  Therefore, when the drive shaft 710 is driven while the lift amount of the plunger 620 is minimized, as shown in FIG. 10, the stroke amount of the plunger 620 is minimized, the pushing amount for pushing the spring 680 is minimized, and mechanical friction is obtained. Can be reduced. Further, when the drive shaft 710 is driven while the lift amount of the plunger 620 is maximized, the stroke amount of the plunger 620 is maximized as shown in FIG. 11, and the fuel pressure discharged from the high-pressure fuel pump 600 is maximized. it can. Note that the fuel pressure discharged from the high-pressure fuel pump 600 can be arbitrarily changed by changing the lift amount of the plunger 620 from the minimum to the maximum.

  The variable mechanism 700 is not limited to the first embodiment described with reference to FIGS. 2 to 7 and the second embodiment described with reference to FIGS. 8 to 11, and the lift amount of the plunger 620 of the high-pressure fuel pump 600 can be changed. Any configuration may be used as long as it is present.

Next, a control system of the high pressure fuel pump 600 will be described.
A fuel pressure sensor 800 that detects an actual fuel pressure (actual fuel pressure) Pa discharged from the pressurizing chamber 610C is attached to the high-pressure fuel pipe 520. The output signal of the fuel pressure sensor 800 is input to a fuel pump control device 810 having a built-in microcomputer. In addition, the fuel pump control device 810 can be configured to read the target fuel pressure Pt, the rotational speed Ne of the internal combustion engine 100, and the load Q, for example, via an in-vehicle network 820 such as a CAN (Controller Area Network). The engine control device 830 that electronically controls 100 is communicably connected. For example, the engine control device 830 obtains a target fuel pressure according to the rotational speed Ne and the load Q of the internal combustion engine 100, and transmits this to the fuel pump control device 810. The fuel pump control device 810 is an example of the control device.

  Here, as the load Q of the internal combustion engine 100, for example, a state quantity closely related to the torque of the internal combustion engine 100 such as an intake flow rate, a suction negative pressure, a boost pressure, and an accelerator opening degree can be used. Further, the fuel pump control device 810 can read the rotation speed Ne and the load Q from a known sensor instead of reading the rotation speed Ne and the load Q from the engine control device 830.

  As shown in FIG. 12, the fuel pump control device 810 and the engine control device 830 include a processor A such as a CPU (Central Processing Unit), a non-volatile memory B such as a flash ROM (Read Only Memory), and a RAM (Random Access). A volatile memory C such as a memory), an input / output circuit D serving as an interface with an external device, and a bus E that connects these to each other so that they can communicate with each other.

  The fuel pump control device 810 obtains the operation amounts of the solenoid actuator 640 and the variable mechanism 700 based on the actual fuel pressure Pa, the target fuel pressure Pt, the rotational speed Ne, and the load Q by a control program stored in the nonvolatile memory B, respectively. . The fuel pump control device 810 outputs an operation signal corresponding to the operation amount to the solenoid actuator 640 and the variable mechanism 700, thereby electronically controlling them according to the operating state of the internal combustion engine 100.

  That is, the fuel pump control device 810 minimizes the lift amount of the plunger 620 by the variable mechanism 700 when the pressure of the fuel supplied from the high pressure fuel pump 600 to the fuel injection valve 200 is less than a predetermined value, and mechanical friction of the spring 680 is achieved. Reduce. On the other hand, the fuel pump control device 810 changes the lift amount of the plunger 620 by the variable mechanism 700 according to the fuel pressure when the pressure of the fuel supplied from the high pressure fuel pump 600 to the fuel injection valve 200 is a predetermined value or more. The fuel pressure required by the internal combustion engine 100 is ensured.

  FIG. 13 shows the fuel pressure control of the high-pressure fuel pump 600 that is repeatedly executed every predetermined time by the processor A of the fuel pump control device 810 when the fuel pump control device 810 is started in conjunction with the operation of the ignition key. An example is shown.

  In step 1 (abbreviated as “S1” in the figure, the same applies hereinafter), it is determined whether or not the actual fuel pressure Pa read from the fuel pressure sensor 800 by the processor A of the fuel pump control device 810 has not reached the target fuel pressure. Then, it is determined by feedback control whether or not the actual fuel pressure Pa has converged to the target fuel pressure. That is, the processor A of the fuel pump control device 810 determines whether or not the actual fuel pressure Pa has decreased to the target fuel pressure when the target fuel pressure decreases, or whether or not the actual fuel pressure Pa has increased to the target fuel pressure when the target fuel pressure increases. Determine whether. If the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa has not reached the target fuel pressure (Yes), the process proceeds to step 2. On the other hand, if the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa has reached the target fuel pressure (No), the processor A ends the process to maintain the state.

  In step 2, the processor A of the fuel pump control device 810 determines whether or not the actual fuel pressure Pa is equal to or greater than a predetermined value. Here, the predetermined value is a threshold value for determining whether or not it is necessary to increase the lift amount of the plunger 620 by the variable mechanism 700, and is set as shown below. If the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is equal to or higher than the predetermined value (Yes), the process proceeds to step 3. On the other hand, if the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is less than the predetermined value (No), the process proceeds to step 6.

[How to set a predetermined value]
The fuel pressure discharged from the high-pressure fuel pump 600 varies depending on the rotational speed Ne and the load Q of the internal combustion engine 100 when the opening degree of the intake valve 630 and the lift amount of the plunger 620 are constant. That is, the plunger 620 of the high-pressure fuel pump 600 reciprocates at a cycle proportional to the rotational speed Ne of the internal combustion engine 100 to boost the fuel, and the fuel boosted by the reciprocation of the plunger 620 is a load on the internal combustion engine 100. Consumed according to Q. For this reason, whether or not the lift amount needs to be changed by the variable mechanism 700 varies depending on the rotational speed Ne and the load Q of the internal combustion engine 100.

  Therefore, through experiments and the like, as shown in FIG. 14, a predetermined value that defines the boundary between the fixed region and the operating region of the variable mechanism 700, which changes according to the rotational speed and load of the internal combustion engine 100, is obtained and mapped. And stored in the nonvolatile memory B. Then, the processor A of the fuel pump control device 810 refers to this map to obtain a predetermined value corresponding to the rotational speed Ne and the load Q of the internal combustion engine 100. Note that the predetermined value shown in FIG. 14 is merely an example, and does not necessarily change with the illustrated characteristics.

  As shown in FIG. 15, the predetermined value can be set to be equal to or lower than the control upper limit of the fuel pressure adjustment range by the intake valve 630. In this way, the fuel pressure adjustment range by the intake valve 630 and the fuel pressure adjustment range by the variable mechanism 700 overlap, so that, for example, problems that occur when a predetermined value is set as the control upper limit can be avoided.

  In step 3, the processor A of the fuel pump control device 810 determines whether or not the actual fuel pressure Pa is near the target fuel pressure, for example, within a range having a predetermined width centered on the target fuel pressure. If the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is near the target fuel pressure (Yes), the process proceeds to step 4. On the other hand, if the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is not near the target fuel pressure (No), the process proceeds to step 5.

  In step 4, the processor A of the fuel pump control device 810 supplies the solenoid actuator 640 with the deviation between the actual fuel pressure Pa and the target fuel pressure in order to finely adjust the fuel pressure by adjusting the opening of the intake valve 630. Change the duty ratio of (Pulse Width Modulation). As a result, the fuel pressure of the high-pressure fuel pump 600 is feedback-controlled to the target fuel pressure.

  In step 5, the processor A of the fuel pump control device 810 changes the operation amount of the variable mechanism 700 according to the deviation between the actual fuel pressure Pa and the target fuel pressure in order to adjust the fuel pressure by the variable mechanism 700. As a result, the fuel pressure of the high-pressure fuel pump 600 is feedback-controlled to the target fuel pressure.

  In step 6, the processor A of the fuel pump control device 810 determines whether the lift amount of the plunger 620 is minimized by the variable mechanism 700, for example, via the control state of the variable mechanism 700. If the processor A of the fuel pump control device 810 determines that the lift amount of the plunger 620 is minimum (Yes), the process proceeds to step 7. On the other hand, if the processor A of the fuel pump control device 810 determines that the lift amount of the plunger 620 is not the minimum (No), the process proceeds to step 8.

  In step 7, the duty ratio supplied to the solenoid actuator 640 by the processor A of the fuel pump control device 810 in accordance with the deviation between the actual fuel pressure Pa and the target fuel pressure in order to finely adjust the fuel pressure by adjusting the opening of the intake valve 630. Feedback control.

  In step 8, the processor A of the fuel pump control device 810 changes the operation amount of the variable mechanism 700 so as to minimize the lift amount of the plunger 620. When the lift amount of the plunger 620 is minimized, the stroke of the plunger 620 lifted by the cam 660A of the cam mechanism 660 is reduced, and mechanical friction due to the biasing force of the spring 680 can be reduced.

  According to the fuel pump control device 810, if the fuel pressure supplied from the high-pressure fuel pump 600 to the fuel injection valve 200 does not reach the target fuel pressure, the variable mechanism is determined by comparing the actual fuel pressure Pa with a predetermined value. It is determined whether or not the lift amount of the plunger 620 by 700 is necessary. At this time, since the predetermined value for determining the necessity of the variable mechanism 700 is dynamically set according to the rotational speed Ne and the load Q of the internal combustion engine 100, the determination accuracy can be improved. Note that the predetermined value may be a fixed value as long as the required determination accuracy can be ensured.

  If adjustment of the lift amount of the plunger 620 by the variable mechanism 700 is necessary and the actual fuel pressure Pa is not near the target fuel pressure, the lift amount of the plunger 620 is adjusted by the variable mechanism 700. When the actual fuel pressure Pa is close to the target fuel pressure, the fuel pressure is finely adjusted by adjusting the opening of the intake valve 630. If the actual fuel pressure Pa is in the vicinity of the target fuel pressure, it is not necessary to adjust the lift amount of the plunger 620 by the variable mechanism 700, so the fuel pressure is finely adjusted only by adjusting the opening of the intake valve 630. In short, the change in the lift amount of the plunger 620 by the variable mechanism 700 has priority over the fuel pressure adjustment by the intake valve 630 (the same applies hereinafter).

  On the other hand, if adjustment of the lift amount of the plunger 620 by the variable mechanism 700 is unnecessary and the lift amount of the plunger 620 is not the minimum, the lift amount of the plunger 620 is adjusted to the minimum by the variable mechanism 700. When the lift amount of the plunger 620 is minimized, the fuel pressure is finely adjusted by adjusting the opening of the intake valve 630. If the lift amount of the plunger 620 is the minimum, the adjustment of the lift amount of the plunger 620 by the variable mechanism 700 is unnecessary, so that the fuel pressure is finely adjusted only by adjusting the opening of the intake valve 630.

  Therefore, when the fuel pressure discharged from the high-pressure fuel pump 600 is less than a predetermined value, the lift amount of the plunger 620 by the variable mechanism 700 is minimized, and the mechanical friction pushing the spring 680 can be reduced. When the mechanical friction of the spring 680 is reduced, the load of the cam mechanism 660 that reciprocates the plunger 620 is also reduced, and the rotational energy for driving the same is reduced, so that fuel efficiency can be improved. When the fuel pressure is greater than or equal to a predetermined value, the lift amount of the plunger 620 is adjusted by the variable mechanism 700, so that the fuel pressure required by the internal combustion engine 100 can be ensured.

  Whether or not the adjustment of the lift amount of the plunger 620 by the variable mechanism 700 is necessary is not limited to the comparison between the actual fuel pressure Pa and a predetermined value, and can be determined as follows. That is, the processor A of the fuel pump control apparatus 810 can execute step 21 and step 22 shown in FIG. 16 instead of step 2 in FIG.

  In step 21, the processor A of the fuel pump control device 810 determines whether or not the actual fuel pressure Pa read from the fuel pressure sensor 800 is equal to or higher than a first predetermined value. If the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is equal to or higher than the first predetermined value (Yes), the process proceeds to step 22. On the other hand, if the processor A of the fuel pump control device 810 determines that the actual fuel pressure Pa is less than the first predetermined value (No), the process proceeds to step 6.

  In step 22, the opening degree of the intake valve 630 (intake valve opening degree) is set to the second predetermined value by the processor A of the fuel pump control device 810 via, for example, the duty ratio of PWM supplied to the solenoid actuator 640. It is determined whether or not: If the processor A of the fuel pump control device 810 determines that the intake valve opening is equal to or smaller than the second predetermined value (Yes), the process proceeds to step 3. On the other hand, if the processor A of the fuel pump control device 810 determines that the intake valve opening is larger than the second predetermined value (No), the process proceeds to step 6.

  Here, since the fuel pressure of the high-pressure fuel pump 600 changes according to the rotational speed Ne of the internal combustion engine 100 as described above, the first predetermined value can also be set according to the rotational speed Ne. In this case, the first predetermined value has a characteristic of gradually increasing with respect to the rotational speed Ne of the internal combustion engine 100. In addition, since the fuel pressure of the high-pressure fuel pump 600 changes depending on the intake valve opening, the influence of the fuel pressure change can be reduced by appropriately setting the second predetermined value.

  Then, as shown in FIG. 17, the operation region and the fixed region of the variable mechanism 700 are dynamically determined according to the intake valve opening degree and the actual fuel pressure as shown in FIG. There is an effect.

If the required control accuracy can be ensured, the process of step 22 can be omitted. In this case, the first predetermined value in step 21 is an example of a predetermined value for determining whether or not the lift amount needs to be adjusted by the variable mechanism 700.
Here, the claims at the time of filing are as follows.
[Claim 1]
A fuel injection valve that directly injects fuel into the cylinder;
A fuel pump that lifts a plunger against a biasing force of a spring by a cam mechanism driven by an internal combustion engine and boosts fuel to supply the fuel to the fuel injection valve;
A variable mechanism for changing the amount of lift of the plunge;
An internal combustion engine control device comprising:
When the pressure of the fuel supplied from the fuel pump to the fuel injection valve is less than a predetermined value, the variable mechanism minimizes the lift amount of the plunger, and when the pressure of the fuel exceeds the predetermined value, The lift amount of the plunger is changed by the variable mechanism according to pressure,
A control device for an internal combustion engine.
[Claim 2]
The internal combustion engine further includes a pressure regulating mechanism for regulating the pressure of the fuel boosted by the fuel pump,
Adjusting the fuel by the pressure adjusting mechanism based on the pressure of the fuel;
The control apparatus for an internal combustion engine according to claim 1.
[Claim 3]
Prioritizing the change in the lift amount of the plunger by the variable mechanism over the pressure adjustment of the fuel by the pressure adjustment mechanism,
The control apparatus for an internal combustion engine according to claim 2.

100 Internal combustion engine 200 Fuel injection valve 600 High-pressure fuel pump (fuel pump)
620 Plunger 630 Suction valve 640 Solenoid actuator 660 Cam mechanism 680 Spring 700 Variable mechanism 810 Fuel pump control device (control device)

Claims (3)

A fuel injection valve that directly injects fuel into the cylinder;
A fuel pump driven by an internal combustion engine to lift the plunger against the biasing force of the spring and reduce the volume of the pressurizing chamber to boost the fuel and supply the fuel to the fuel injection valve;
A variable mechanism for changing the lift amount of the plunger;
A suction valve for regulating the pressure of the fuel flowing into the pressurizing chamber;
An internal combustion engine control device comprising:
When the pressure of the fuel supplied from the fuel pump to the fuel injection valve is less than a predetermined value, the variable mechanism minimizes the lift amount of the plunger ,
When pressure before Symbol fuel of the predetermined value or more, when the lift amount of the plunger by the friendly varying mechanism to change in accordance with the pressure of the fuel, the pressure of the fuel is changed by a change of the lift amount, the suction Adjust the opening of the valve ,
A control device for an internal combustion engine. When the pressure of the fuel is equal to or greater than the predetermined value, when the pressure of the fuel is within a predetermined range near the target fuel pressure according to the engine operating state, the opening degree adjustment of the intake valve is started.
The control apparatus for an internal combustion engine according to claim 1. When the pressure of the fuel is less than the predetermined value, the opening of the intake valve is adjusted when the lift amount of the plunger is minimized.
The control apparatus for an internal combustion engine according to claim 1 or 2, characterized by the above.