JP2008196451A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device to be applied to an internal combustion engine consisting of a direct injection valve, a port injection valve, a mechanism utilizing hydraulic pressure for adjusting the phase angle of a camshaft relative to a crankshaft to adjust an intake valve opening/closing timing, a high pressure fuel pump to be driven with the rotation of the camshaft to generate the pressure of direct injection fuel, and a mechanism for controlling the workload of the high pressure fuel pump, wherein the intake valve opening/closing timing quickly corresponds to a target value for the intake valve opening/closing timing when the target value is suddenly changed and even when hydraulic pressure is low. <P>SOLUTION: When the hydraulic pressure is low and the target value VTt for the opening/closing timing of an intake valve 11 is suddenly changed, the control device sets a direct injection amount fic and the duty ratio of a solenoid spill valve 33 to be zero to minimize the workload of the high pressure fuel pump. Herein, a load on the camshaft which drives the high pressure fuel pump is proportional to the workload of the high pressure fuel pump. Thus, the load is minimized to increase the changing speed of an actual opening/closing timing VT of the intake valve 11 which is changed toward the target value VTt. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

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

As one of the control devices for the internal combustion engine, an in-cylinder injection mechanism that injects fuel into the combustion chamber of the internal combustion engine, a port injection mechanism that injects fuel into an intake passage upstream of the intake valve of the internal combustion engine, A first pressure generating mechanism for generating pressure, and adjusting the opening / closing timing of the intake valve corresponding to the relative phase angle between the camshaft that drives the intake valve and the crankshaft of the internal combustion engine using the pressure of the liquid A valve opening / closing timing adjusting mechanism that is driven, a second pressure generating mechanism that is driven by rotation of the camshaft and generates a pressure of fuel injected into the combustion chamber, and a work amount of the second pressure generating mechanism is adjusted Applied to an internal combustion engine having a work amount adjustment mechanism, target value determining means for determining a valve opening / closing timing target value which is a target value of the opening / closing timing of the intake valve, and an actual opening / closing timing of the intake valve is the valve Close to opening / closing timing target value The valve opening / closing timing control means for controlling the valve opening / closing timing adjusting mechanism and the work amount of the second pressure generating mechanism according to the in-cylinder injection amount which is the amount of fuel injected by the in-cylinder injection mechanism Work control means for controlling the work adjustment mechanism to be adjusted, and an injection ratio which is a ratio of the in-cylinder injection amount and the amount of fuel injected by the port injection mechanism to the operating state of the internal combustion engine There is one provided with an injection ratio determining means for determining the basic injection ratio determined based on the above-mentioned, for example, described in Patent Document 1 below.
JP 2006-144629 A

  In such a control apparatus for an internal combustion engine, since the second pressure generating mechanism is generally driven by the rotation of the cam shaft, a load applied to the cam shaft for driving the second pressure generating mechanism (hereinafter referred to as “cam shaft driving load”). ") Is larger as the work amount of the second pressure generating mechanism is larger. On the other hand, the work amount of the second pressure generating mechanism is adjusted by the work amount adjusting mechanism such that the larger the in-cylinder injection amount, the larger the value. Therefore, the camshaft drive load tends to increase as the in-cylinder injection amount increases.

  By the way, generally, the valve opening / closing timing target value is often adjusted according to the accelerator operation amount of the vehicle to which the internal combustion engine is applied. In general, the first pressure generating mechanism is often driven by the rotation of the crankshaft of the internal combustion engine. In this case, when the operating speed of the internal combustion engine is low, the pressure of the liquid generated by driving the first pressure generating mechanism is low.

  Here, let us consider a case where the operating state of the internal combustion engine changes (rapidly changes) with a large change speed, for example, in a state where the operating speed is low, such as an idling state. In this case, when the injection ratio is set to a basic injection ratio with a large ratio of the in-cylinder injection amount, the camshaft driving load increases with a small liquid pressure used for the valve opening / closing timing adjustment mechanism. It becomes difficult to quickly change the relative phase angle between the camshaft and the crankshaft.

  Therefore, the valve opening / closing timing target value changes almost simultaneously with the change of the accelerator operation amount, whereas the actual opening / closing timing of the intake valve changes with a large delay. In other words, there is a problem that it takes time for the actual opening / closing timing of the intake valve to approach the valve opening / closing timing target value.

  Accordingly, an object of the present invention is to control the intake valve in the control device for an internal combustion engine of the above type even when the valve opening / closing timing target value changes suddenly, even when the pressure of the liquid used for the valve opening / closing timing adjusting mechanism is small. Another object is to provide an apparatus that can quickly bring the actual opening / closing timing of the exhaust valve close to the valve opening / closing timing target value.

  The control apparatus for an internal combustion engine according to the present invention includes the in-cylinder injection mechanism, the port injection mechanism, a first pressure generation mechanism that generates a liquid pressure, and the intake valve or the A valve opening / closing timing adjusting mechanism for adjusting an opening / closing timing of the intake valve or the exhaust valve corresponding to a relative phase angle between a camshaft for driving an exhaust valve of the internal combustion engine and a crankshaft of the internal combustion engine; and the second pressure generation The present invention is applied to an internal combustion engine including a mechanism and the work amount adjusting mechanism.

  Here, the “liquid” is, for example, a well-known engine oil that circulates inside the internal combustion engine, and is not limited thereto.

  The control device according to the present invention comprises: target value determining means for determining a target value for valve opening / closing timing which is a target value for opening / closing timing of the intake valve or the exhaust valve; and an actual opening / closing timing of the intake valve or the exhaust valve. A valve opening / closing timing control means for controlling the valve opening / closing timing adjustment mechanism so as to approach the valve opening / closing timing target value; the work amount control means; and the injection ratio determination means.

  A feature of the control device according to the present invention is that, when the injection ratio determining means is such that the pressure of the liquid is less than a predetermined pressure and the change speed of the valve opening / closing timing target value is equal to or higher than the first speed, Instead of the basic injection ratio, the injection ratio is determined to be a first ratio that is a value in which the ratio of the in-cylinder injection amount is smaller than the basic injection ratio.

  By changing and determining the injection ratio to the first ratio instead of the basic injection ratio, the in-cylinder injection amount is reduced and the camshaft drive load is also reduced. According to the above configuration, when the pressure of the liquid is less than a predetermined pressure and the changing speed of the valve opening / closing timing target value is equal to or higher than the first speed, the camshaft driving load becomes smaller. Accordingly, when the valve opening / closing timing target value changes suddenly, the relative phase angle between the camshaft and the crankshaft can change rapidly even when the pressure of the liquid used for the valve opening / closing timing adjustment mechanism is small, and the intake air The actual opening / closing timing of the valve or the exhaust valve can be brought close to the valve opening / closing timing target value quickly.

  By the way, in an internal combustion engine provided with an in-cylinder injection mechanism and a port injection mechanism, the in-cylinder injection amount can be changed without changing the total amount of fuel combusted in the combustion chamber of the internal combustion engine by changing the injection ratio. Can do. For example, when the total amount of fuel is set to the amount of fuel that matches the target air-fuel ratio that is the air-fuel ratio aimed at the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine, the injection ratio is set to the first ratio Even if the in-cylinder injection amount is reduced, the port injection amount is increased to suppress the deviation of the air-fuel ratio of the air-fuel mixture from the target air-fuel ratio to a leaner air-fuel ratio. Can be done. Therefore, in this case, the actual opening / closing timing of the intake valve or the exhaust valve can be quickly brought close to the valve opening / closing timing target value while matching the air / fuel ratio of the mixture to the target air / fuel ratio.

  In the control device according to the present invention, the target value determining means determines the valve opening / closing timing target value for the intake valve and sets the valve opening / closing timing target value for the intake valve as the accelerator operation amount increases. It is comprised so that it may determine so that it may become a value at an advance angle side, and the said injection ratio determination means is that the pressure of the said liquid is less than the said predetermined pressure, and the change speed of the said accelerator operation amount is more than 2nd speed In this case, it is preferable that the injection ratio is determined to be the first ratio instead of the basic injection ratio.

  When the accelerator operation amount of the vehicle to which the internal combustion engine is applied is a large value (that is, when the load amount of the internal combustion engine is a large value), the amount of fresh air drawn into the combustion chamber is increased. From the viewpoint of acceleration, it is preferable that the valve opening / closing timing of the intake valve be controlled so as to be a value on the advance side.

  Further, when the accelerator operation amount is a small value (that is, when the load amount of the internal combustion engine is a small value), the valve opening / closing timing of the intake valve is determined from the viewpoint of improving the stability of fuel combustion in the combustion chamber. It is preferable to control the value so that the value is retarded.

  In addition, when the accelerator operation amount is a medium value (that is, when the load amount of the internal combustion engine is a medium value), the burned gas is actively discharged from the combustion chamber toward the intake passage. From the viewpoint of reducing the pumping loss of the internal combustion engine by performing so-called internal EGR, it is preferable that the valve opening / closing timing of the intake valve is controlled to be a value on the advance side.

  According to the above configuration, when the accelerator operation amount suddenly changes to a large value, even if the pressure of the liquid used for the valve opening / closing timing adjustment mechanism is small, the actual opening / closing timing of the intake valve is It is possible to quickly approach the valve opening / closing timing target value for the intake valve that suddenly changes to a more advanced value with a sudden change in the amount. Therefore, in this case, a static pressure wave is generated from the intake passage toward the combustion chamber, so that the amount of fresh air sucked into the combustion chamber is suppressed while the burned gas is prevented from flowing out from the combustion chamber to the intake passage. Since it can be enlarged quickly, acceleration of the vehicle to which the internal combustion engine is applied can be carried out quickly.

  In addition, when the accelerator operation amount suddenly changes to a small value, the actual opening / closing timing of the intake valve is set to a sudden value of the accelerator operation amount even when the pressure of the liquid used for the valve opening / closing timing adjustment mechanism is small. It is possible to quickly approach the valve opening / closing timing target value for the intake valve that suddenly changes to a retarded side value with the change. Therefore, in this case, it can be suppressed that the combustion of the fuel in the combustion chamber becomes unstable as the accelerator operation amount is suddenly reduced to a small value.

  In addition, when the accelerator operation amount suddenly changes from a small value to a medium value, even if the liquid pressure used for the valve opening / closing timing adjustment mechanism is small, the actual opening / closing timing of the intake valve is It is possible to quickly approach the valve opening / closing timing target value for the intake valve that suddenly changes to a more advanced value as the accelerator operation amount changes suddenly. Therefore, in this case, since the internal EGR can be executed quickly, the pumping loss of the internal combustion engine can be reduced quickly.

  In the control device according to the present invention, it is preferable that the injection ratio determining means is configured to use a value at which the ratio of the in-cylinder injection amount is “0” as the first ratio. . As described above, the camshaft driving load tends to increase as the in-cylinder injection amount increases. Therefore, when the in-cylinder injection amount is “0”, the camshaft driving load is minimized. On the other hand, when determining the first ratio, the calculation load of the CPU is reduced by setting the first ratio as a constant.

  Therefore, according to the above configuration, when the valve opening / closing timing target value changes suddenly, the actual opening / closing timing of the intake valve or the exhaust valve is controlled even if the pressure of the liquid used for the valve opening / closing timing adjustment mechanism is small. While it is possible to approach the opening / closing timing target value more quickly, the calculation load of the CPU related to the determination of the first ratio can be reduced.

  Further, in the control device according to the present invention, the injection ratio determining means is configured such that the degree of difference between the actual opening / closing timing of the intake valve or the exhaust valve and the valve opening / closing timing target value is less than a predetermined level. In some cases, it is preferred that the injection ratio is configured to return to the basic injection ratio.

  From the time when the injection ratio is changed from the basic injection ratio to the first ratio, the actual opening / closing timing of the intake valve or the exhaust valve, which changes toward the valve opening / closing timing target value, and the valve opening / closing timing target value, When the degree of difference becomes small, it is no longer necessary to quickly bring the actual opening / closing timing of the intake valve or exhaust valve close to the valve opening / closing timing target value.

  That is, in this case, since it is not necessary to determine the injection ratio as the first ratio, it is preferable to return the injection ratio from the first ratio to the basic injection ratio. The above configuration is based on such knowledge. According to this, it can be suppressed that the injection ratio is unnecessarily determined as the first ratio, and the opportunity to use the basic injection ratio as the injection ratio can be increased.

  Further, in the control device according to the present invention, the injection ratio determination means causes the in-cylinder injection to occur due to a decrease in the in-cylinder injection amount due to the change of the injection ratio from the basic injection ratio to the first ratio. When it is determined that a deposit is generated in the injection hole of the injection mechanism, it is preferable that the injection ratio is returned to the basic injection ratio.

  After the change of the injection ratio from the basic injection ratio to the first ratio, the temperature in the vicinity of the injection hole of the in-cylinder injection mechanism tends to increase as the in-cylinder injection amount decreases. When the temperature in the vicinity of the injection hole of the in-cylinder injection mechanism becomes excessively high, deposits are often generated in the injection hole of the in-cylinder injection mechanism.

  According to the above configuration, when it is determined that a deposit is generated, the injection ratio is returned from the first injection ratio to the basic injection ratio, so the in-cylinder injection amount increases. Accordingly, an increase in the degree to which the vicinity of the injection hole of the in-cylinder injection mechanism is increased can prevent the temperature in the vicinity of the injection hole of the in-cylinder injection mechanism from becoming excessively high. Can be prevented from being generated. As a result, the occurrence of malfunctions in the in-cylinder injection mechanism such as clogging of the injection holes due to the generation of deposits can be suppressed.

  In the control device according to the present invention, the injection ratio determining means may be configured to return the injection ratio to the basic injection ratio when the pressure of the liquid is equal to or higher than the predetermined pressure. Is preferred. When the liquid pressure increases after the time when the injection ratio is changed from the basic injection ratio to the first ratio, the necessity for reducing the camshaft drive load is small.

  That is, in this case, since it is not necessary to determine the injection ratio as the first ratio, it is preferable to return the injection ratio from the first ratio to the basic injection ratio. The above configuration is based on such knowledge. According to this, it is possible to suppress the injection ratio from being unnecessarily determined to be the first ratio, and it is possible to increase the opportunity to use the basic injection ratio as the injection ratio.

  DESCRIPTION OF EMBODIMENTS Hereinafter, an embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to the drawings.

  FIG. 1 shows a schematic configuration of a valve operating system of a spark ignition type multi-cylinder (6 cylinder) internal combustion engine 10 to which a control device according to an embodiment of the present invention is applied. The internal combustion engine 10 includes an intake valve 11 that opens and closes an intake port communicating with a combustion chamber of the internal combustion engine 10, an intake camshaft 12 that drives the intake valve 11, and an intake cam that is different from the cam that drives the intake valve 11. A high pressure fuel pump drive cam 13 provided on the shaft 12 and a fuel which is disposed in the vicinity of the intake cam shaft 12 and driven by the rotation of the high pressure fuel pump drive cam 13 and injected from a cylinder injection valve 28 which will be described later. A plunger-type high-pressure fuel pump (second pressure generating mechanism) 14 for generating pressure, and an end portion of the intake camshaft 12 are arranged coaxially with the intake camshaft 12 so as to be rotatable integrally with the intake camshaft 12, and the phase angle is continuously increased. The variable intake timing device (the valve opening / closing timing adjusting mechanism) 15 to be changed and the pressure of the engine oil (the liquid) are generated. An oil pump (first pressure generating mechanism) 16 for supplying engine oil stored in an oil pan of the internal combustion engine 10 to the variable intake timing device 15 and an exhaust valve for opening and closing an exhaust port communicating with the combustion chamber of the internal combustion engine 10 17, an exhaust camshaft 18 that drives the exhaust valve 17, a sprocket 19 that is coaxially and integrally rotatable with the exhaust camshaft 18 at the end of the exhaust camshaft 18, a crankshaft 20, and a crankshaft The intake camshaft 12 and the exhaust camshaft 18 are connected to the end of 20 via a sprocket 21 coaxially and integrally rotatable with the crankshaft 20, a sprocket 15 b of the variable intake timing device 15, and sprockets 19, 21. And crankshaft 20 of FIG. And a timing chain 22 connecting integrally rotatably in the direction of the arrow of the line. The intake camshaft 12 and the exhaust camshaft 18 are rotated once via the timing chain 22 every time the crankshaft 20 is rotated twice. The oil pump 16 is driven by rotation of the crankshaft 20.

  The variable intake timing device 15 includes a housing member 15a, a sprocket 15b disposed integrally with the housing member 15a on the other end side of the housing member 15a, and the housing member 15a coaxially and relatively rotatable with the housing member 15a. A rotor member 15c that is disposed so as to define an advance angle chamber and a retard angle chamber on the inner side, and that is disposed coaxially with the intake camshaft 12 and rotatable integrally with the intake camshaft 12; An oil supply passage 15d that communicates one of the engine oil inlets of the advance chamber and the retard chamber and the engine oil outlet of the oil pump 16, and the engine oil outlets of the advance chamber and the retard chamber An oil discharge passage (not shown) that allows engine oil to flow out from either side toward the oil pan, an advance angle chamber, and a delay time And a well-known oil passage switching mechanism (not shown) switches the engine oil supply and discharge to chamber.

  The oil passage switching mechanism will be described later so that the actual opening / closing timing VT of the intake valve 11 detected as described later matches the target value VTt of the opening / closing timing of the intake valve 11 determined as described later. In response to an instruction from the electric control device 50, the supply and discharge of engine oil to the advance chamber and the retard chamber are switched. More specifically, when the opening / closing timing deviation dVT, which is a value obtained by subtracting the target value VTt of the opening / closing timing of the intake valve 11 from the actual opening / closing timing VT of the intake valve 11, is a positive value (that is, the intake valve 11 When the actual opening / closing timing VT is a value retarded from the target value VTt), the oil passage switching mechanism allows the advance chamber and the oil supply passage 15d to communicate with each other, and the retard chamber, the oil discharge passage, Is instructed from the electric control device 50 so as to communicate with each other.

  As a result, the engine oil is supplied to the advance chamber and discharged from the retard chamber to the oil pan using the pressure generated by the oil pump 16 as a pressure source, so that the intake camshaft 12 is integrated with the rotor member 15c. 1 relative to the housing member 15a along the direction of the arrow A shown by the broken line in FIG. 1, the relative phase angle of the intake camshaft 12 with the crankshaft 20 becomes a more advanced value, and the intake air The actual opening / closing timing VT of the valve 11 is adjusted to become a value on the more advanced side, and the opening / closing timing deviation dVT approaches “0”.

  On the other hand, when the opening / closing timing deviation dVT is a negative value (that is, when the actual opening / closing timing VT of the intake valve 11 is a value advanced from the target value VTt), the oil passage switching mechanism An instruction is received from the electric control device 50 so that the chamber and the oil supply passage 15d communicate with each other, and the advance chamber and the oil discharge passage communicate with each other.

  Thus, the engine oil is supplied to the retard chamber and discharged from the advance chamber to the oil pan using the pressure generated by the oil pump 16 as a pressure source, so that the intake camshaft 12 is integrated with the rotor member 15c. 1 relative to the housing member 15a along the direction of the arrow B shown by the broken line in FIG. 1, the relative phase angle of the intake camshaft 12 with respect to the crankshaft 20 becomes a more retarded value, and the intake air The actual opening / closing timing VT of the valve 11 is adjusted so as to become a more retarded value, and the opening / closing timing deviation dVT approaches “0”.

  When the opening / closing timing deviation dVT becomes “0”, the oil passage switching mechanism receives an instruction from the electric control device 50 to prohibit the supply of engine oil to the advance chamber and the retard chamber. ing. As a result, relative rotation between the rotor member 15c (accordingly, the intake camshaft 12) and the housing member 15a (accordingly, the crankshaft 20) is prohibited, so that the actual opening / closing timing VT of the intake valve 11 becomes the intake valve 11. The state coincident with the target value VTt of the opening / closing timing is maintained. As described above, the valve opening / closing timing adjustment mechanism uses the pressure of the liquid generated by the first pressure generation mechanism as a pressure source, and the liquid is supplied to the advance chamber or the retard chamber, so that the intake valve 11 or the exhaust valve The opening / closing timing of the valve 17 is adjusted.

  Next, the configuration of the fuel supply system of the internal combustion engine 10 to which the control device according to the embodiment of the present invention is applied will be described with reference to FIG. FIG. 2 shows a schematic configuration of the fuel supply system of the internal combustion engine 10. The internal combustion engine 10 further includes six port injection valves 23 for injecting fuel into the intake ports corresponding to the six cylinders, and a port-side delivery pipe 24 for equally distributing the fuel to the port injection valves 23, respectively. And a port-side fuel passage 27 that communicates a fuel outlet of the electric feed pump 26 that feeds fuel from a fuel tank 25 provided in a vehicle to which the internal combustion engine 10 is applied and a fuel inlet of the port-side delivery pipe 24. . The port injection valve 23, the port side delivery pipe 24, and the port side fuel passage 27 constitute the port injection mechanism. The port-side fuel passage 27 includes a cylinder injection valve 28 and a relief valve mechanism (not shown) that returns the fuel fed from the electric feed pump 26 to the fuel tank 25 during a period when fuel is not injected from the port injection valve 23. I have.

  The internal combustion engine 10 further includes six in-cylinder injection valves 28 for injecting fuel into the combustion chambers corresponding to the six cylinders, and a cylinder inner side for equally distributing the fuel to the in-cylinder injection valves 28, respectively. A delivery pipe 29, a first cylinder inner fuel passage 30 that communicates a predetermined position of the port side fuel passage 27 and a fuel inlet of the high pressure fuel pump 14, a fuel outlet of the high pressure fuel pump 14, and a cylinder inner delivery pipe 29 A second cylinder inner fuel passage 31 that communicates with the fuel inlet, and a reverse flow of fuel from the cylinder injection valve 28 side to the high pressure fuel pump 14 side that is disposed at a predetermined position of the second cylinder inner fuel passage 31. A check valve 32 for preventing, and an electromagnetic spill valve (the work amount adjusting mechanism) 33 which is disposed at a predetermined position of the first cylinder inner fuel passage 30 and adjusts the work amount of the high-pressure fuel pump 14 as will be described later. I have. The in-cylinder injection mechanism is configured by the in-cylinder injection valve 28, the in-cylinder delivery pipe 29, the first in-cylinder inner fuel passage 30, the second in-cylinder inner fuel passage 31, and the check valve 32.

  The high-pressure fuel pump 14 has a cylinder 14a having a fuel inlet at one end and a fuel outlet at a predetermined position on a side surface, one end of the cylinder 14a is fitted to the cylinder 14a, and the other end is in contact with the cam 13 for driving the high-pressure fuel pump. A plunger 14b disposed so as to be capable of reciprocating relative to the cylinder 14a, and a coil spring 14c interposed between the cylinder 14a and the plunger 14b and biasing the plunger 14b away from the cylinder 14a. I have.

  In the high-pressure fuel pump 14, the plunger 14b moves upward relative to the cylinder 14a against the elastic force of the coil spring 14c by the rotation of the cam 13 for driving the high-pressure fuel pump, whereby the cylinder 14a The pressure chamber 14d formed on the top surface of the plunger 14b and the volume of the pressurizing chamber 14d are reduced, so that the fuel is discharged from the fuel outlet, and the plunger 14b is urged by the coil spring 14c and is relative to the cylinder 14a. In particular, by moving downward in FIG. 2, the suction stroke in which the fuel is sucked from the fuel inflow port is repeated alternately by increasing the volume of the pressurizing chamber 14d.

  That is, the second pressure generating mechanism is a plunger type pump, and the rotation of the cam provided on the intake camshaft 12 or the exhaust camshaft 18 is different from the cam that drives the intake valve 11 or the exhaust valve 17. In response to the relative reciprocation of the plunger 14b driven by the cylinder 14a, the fuel injected by the in-cylinder injection mechanism is sucked and discharged to generate the pressure of the fuel. Yes.

  The electromagnetic spill valve 33 has a valve shaft on one end side, a valve body 33a that enables the first cylinder inner fuel passage 30 and the pressurizing chamber 14d of the high-pressure fuel pump 14 to be disconnected and communicated, and a valve shaft of the valve body 33a. A coil spring 33b for urging the valve body 33a downward in FIG. 2 and a solenoid 33c disposed so as to surround the valve shaft are provided.

  The solenoid 33c is configured such that the energization period is controlled by the electric control device 50. When the energization of the solenoid 33c is continued, the valve element 33a moves upward in FIG. 2 (that is, the valve closing direction) against the elastic force of the coil spring 33b, so that the first cylinder inner fuel The passage 30 and the pressurizing chamber 14d of the high-pressure fuel pump 14 are shut off.

  On the other hand, when the energization to the solenoid 33c is stopped, the valve element 33a moves downward in FIG. 2 (that is, the valve opening direction) while being urged by the coil spring 33b, whereby the first cylinder inner fuel The passage 30 and the pressurizing chamber 14d of the high pressure fuel pump 14 are communicated with each other.

  The work of the high-pressure fuel pump 14 driven as described above will be described with reference to FIG. FIG. 3 shows the time and the lift of the plunger 14b when the plunger 14b of the high-pressure fuel pump 14 reciprocates once in the period of time t0 to t1 (ie, in one cycle) by the rotation of the cam 13 for driving the high-pressure fuel pump. It is the graph which showed the relationship with quantity. Here, the time t0, t1 is the time when the lift amount of the plunger 14b is the minimum, and the time t2 (<time t1) is the time when the lift amount of the plunger 14b is the maximum, the period of time t0 to t3 (<time t2) Consider a case where energization to the solenoid 33c of the electromagnetic spill valve 33 is stopped and energization to the solenoid 33c is continued for a period of time t3 to t2.

  In this case, during the period from time t0 to t2 (that is, the period corresponding to the above-described pressure feed stroke), the pressure chamber 14d decreases as the lift amount of the plunger 14b increases due to the rotation of the cam 13 for driving the high-pressure fuel pump. Keep doing. On the other hand, the opening of the valve element 33a is maintained during the period from time t0 to t3, so that the first cylinder inner fuel passage 30 and the pressurizing chamber 14d of the high pressure fuel pump 14 communicate with each other, and the first cylinder inner fuel passage is communicated. The fuel is allowed to flow between the pressure chamber 30 and the pressurizing chamber 14d. Therefore, during the period from time t0 to t3, the fuel filled in the pressurizing chamber 14d continues to overflow from the pressurizing chamber 14d to the first cylinder inner fuel passage 30 as the pressurizing chamber 14d decreases.

  On the other hand, the valve body 33a is kept closed during the period from the time t3 to the time t2, whereby the first cylinder inner fuel passage 30 and the pressurizing chamber 14d of the high pressure fuel pump 14 are shut off, and the first cylinder inner fuel passage is closed. The flow of fuel between 30 and the pressurizing chamber 14d is prohibited. Therefore, during the period from the time t3 to the time t2, the above-described fuel overflow is prohibited, and the fuel is pumped (discharged) to the second cylinder inner fuel passage 31 according to the decrease in the pressurizing chamber 14d. An amount of fuel corresponding to the pressure-fed amount is injected from the in-cylinder injection valve 28.

  Here, the in-cylinder injection amount, which is the amount of fuel injected from the in-cylinder injection valve 28, is the ratio of the period from time t3 to t2 with respect to the period from time t0 to t2 (hereinafter referred to as “duty ratio”). The larger the value, the larger.

  Further, the work amount of the high-pressure fuel pump 14 corresponds to the energy required for the fuel pumping, and therefore corresponds to the area of the region shown by the oblique lines in FIG. Therefore, the work amount of the high-pressure fuel pump 14 in the period from time t0 to t2, that is, in the pumping stroke, increases as the duty ratio increases.

  From the above, the work amount of the high-pressure fuel pump 14 in the period from the time t0 to t2 is larger as the in-cylinder injection amount is larger. That is, when the second pressure generating mechanism is a plunger-type pump such as the high-pressure fuel pump 14, the work amount is a work amount for each reciprocation (per cycle) of the pump plunger. It is proportional to the amount of fuel discharged.

  On the other hand, when the second pressure generation mechanism is, for example, a rotary pump driven by rotation of the cam shaft of the intake valve 11 or the exhaust valve 17, the work amount is a work amount per rotation of the pump. , Proportional to the power of the pump, that is, the discharge flow rate of the pump.

  On the other hand, the work amount adjusting mechanism is configured to adjust the work amount of the second pressure generating mechanism by adjusting an effective time of discharge of the fuel injected by the in-cylinder injection mechanism. In particular, when the duty ratio is “0”, the work amount of the high-pressure fuel pump 14 during the period from time t0 to t2 is minimized (sliding resistance applied to the lift of the plunger 14b, elastic force of the coil spring 14c, etc.) In addition, the in-cylinder injection amount becomes “0”.

  During the period from time t2 to t1 (period corresponding to the suction stroke), the lift amount of the plunger 14b is decreased by the rotation of the cam 13 for driving the high-pressure fuel pump, so that the pressurizing chamber 14d continues to increase. On the other hand, the energization of the solenoid 33c is stopped during the period of time t2 to t1, so that the valve body 33a is kept open, and the first cylinder inner fuel passage 30 and the pressurizing chamber 14d of the high pressure fuel pump 14 are connected. The fuel is allowed to flow between the first cylinder inner fuel passage 30 and the pressurizing chamber 14d.

  Therefore, during the period from time t2 to t1, the fuel filled in the first cylinder inner fuel passage 30 is sucked into the pressurizing chamber 14d as the pressurizing chamber 14d increases. That is, since the fuel is sucked only by the elastic force of the coil spring 14c, the work amount of the high-pressure fuel pump 14 during the period from the time t2 to the time t1 is substantially “0”.

  The load of the intake camshaft 12 for driving the high-pressure fuel pump 14 (hereinafter referred to as “camshaft drive load”) is the work of the high-pressure fuel pump 14 (in the pumping stroke) for each reciprocation of the plunger 14b. The bigger the amount, the bigger. That is, the camshaft drive load increases as the duty ratio and the in-cylinder injection amount increase. The above is the description of the work amount of the high-pressure fuel pump 14.

  On the other hand, this fuel supply system includes a hot-wire air flow meter 41 that detects a mass flow rate Ga per unit time of intake air flowing through the intake pipe of the internal combustion engine 10, a cam position sensor 42 that detects an opening / closing timing VT of the intake valve 11, A crank position sensor 43 that detects the operating speed NE of the internal combustion engine 10, a hydraulic pressure sensor 44 that detects the pressure Po of engine oil generated by driving the oil pump 16, and an accelerator operation amount by the driver of the vehicle to which the internal combustion engine 10 is applied An accelerator opening sensor 45 that detects Accp and an electric control device 50 including a CPU, a routine executed by the CPU, a table, and the like are provided.

  The electric control device 50 is connected to the sensors 41 to 45, the port injection valve 23, the in-cylinder injection valve 28, and the solenoid 33c of the electromagnetic spill valve 33, and supplies signals from the sensors 41 to 45 to the CPU. Drive signals are sent to the port injection valve 23, the in-cylinder injection valve 28, and the solenoid 33c of the electromagnetic spill valve 33 in accordance with instructions from the CPU.

(Actual operation)
Next, the actual operation of the electric control device 50 will be described with reference to the series of flowcharts shown in FIGS. 4 and 5 and the time chart shown in FIG.

  FIG. 6 is a time chart showing changes in various variables when the accelerator operation amount Accp maintained at the small value Accp1 suddenly becomes a large value Accp2 (> value Accp1) at time t10.

  In this embodiment, the injection ratio R is the in-cylinder injection amount fic of the in-cylinder injection amount fic that is the amount of fuel injected from the in-cylinder injection valve 28 and the amount of fuel injected from the port injection valve 23. It is a ratio to the sum of a certain port injection amount fip (that is, R = fic / (fic + fip)). In addition, the injection ratio R is usually obtained by using the operating speed NE obtained based on the output of the crank position sensor 43, the in-cylinder intake air amount Mc that is the amount of air sucked into the combustion chamber, and NE and Mc as arguments. The basic injection ratio determined based on the table MapR is set.

  The CPU of the electric control device 50 starts the process from step 400 of the routine for calculating the in-cylinder injection amount fic and the port injection amount fip and instructing the fuel injection shown in the flowchart of FIG. Based on the speed NE, the accelerator operation amount Accp obtained based on the output of the accelerator opening sensor 45, and the table MapVTt using NE and Accp as arguments, the target value VTt of the opening / closing timing of the intake valve 11 is determined. The target value VTt of the opening / closing timing of the intake valve 11 is determined by the table MapVTt so that it becomes a more advanced value as the accelerator operation amount Accp is larger. This step 405 corresponds to a part of the target value determining means.

  Next, the CPU proceeds to step 410 and the actual opening / closing timing of the intake valve 11 obtained based on the target value VTt of the opening / closing timing of the intake valve 11 determined as described above and the output of the cam position sensor 42. Based on VT, the above opening / closing timing deviation dVT is obtained. In a routine for instructing switching of the oil passage switching mechanism (not shown separately), when dVT> 0, the CPU supplies (discharges) engine oil to the advance chamber (from the retard chamber), If dVT <0, supply (discharge) engine oil to the retard chamber (from the advance chamber). If dVT = 0, stop supplying engine oil to the advance chamber and retard chamber. The oil passage switching mechanism is instructed to be executed. A routine for instructing switching of the oil passage switching mechanism corresponds to a part of the valve opening / closing timing control means.

  Next, the CPU proceeds to step 415 to determine whether or not the flag Z is “0”. When the value of the flag Z is “0”, the injection ratio R is determined as the basic injection ratio. When the value is “1”, the injection ratio R is the first ratio “0”. This represents the case where it is determined.

  First, a case where the value of the flag Z is “0” before time t10 will be described. In this case, the CPU makes a “Yes” determination at step 415 to proceed to step 420 to determine whether or not the changing speed dAccp of the accelerator operation amount Accp is equal to or higher than a predetermined speed α (the second speed).

  When the CPU determines “Yes” in step 420, the process proceeds to step 425 to determine whether or not the engine oil pressure Po obtained based on the output of the hydraulic sensor 44 is less than a predetermined pressure β. . Here, if any one of the conditions in steps 420 and 425 is not satisfied, the CPU makes a “No” determination in any of steps 420 and 425 and immediately proceeds to step 430 in FIG. It is determined whether or not the value of “1” is “1”.

  At this time, the accelerator operation amount Accp is maintained at the value Accp1 and the value of the flag Z is “0”. Accordingly, the CPU makes a “No” determination at step 420, determines “No” at the subsequent step 430, and proceeds to step 435, in which the injection ratio R is determined based on the operating speed NE, the in-cylinder intake air amount Mc, and the like. Then, the basic injection ratio determined based on the table MapR (NE, Mc) is set. Thereby, the basic injection ratio that is an appropriate injection ratio according to the operation speed NE that changes from moment to moment and the in-cylinder intake air amount Mc can be determined.

  Here, the in-cylinder intake air amount Mc is calculated based on, for example, the air mass flow rate Ga obtained based on the output of the air flow meter 41, the operation speed NE, and the table MapMc using Ga and NE as arguments. It is estimated that the larger the mass flow rate Ga, the larger the value. Further, since the air mass flow rate Ga increases as the accelerator operation amount Accp increases, the in-cylinder intake air amount Mc is estimated to increase as the accelerator operation amount Accp increases.

  Next, the CPU proceeds to step 440 and determines the in-cylinder injection amount fic based on the injection ratio R determined as described above, the basic fuel injection amount Fbase, and the formula described in step 440. To do. Here, the basic fuel injection amount Fbase is obtained by dividing the in-cylinder intake air amount Mc by the target air-fuel ratio abyfr that is the air-fuel ratio aimed at the air-fuel ratio of the air-fuel mixture supplied to the internal combustion engine 10. Amount.

  Next, the CPU proceeds to step 445 to determine the port injection amount fip based on the injection ratio R determined as described above, the basic fuel injection amount Fbase, and the equation described in step 445. . Subsequently, the CPU proceeds to step 450 and adjusts the solenoid 33c so that the energization period of the electromagnetic spill valve 33 to the solenoid 33c becomes a duty ratio corresponding to the in-cylinder injection amount fic determined as described above. Instruct (see FIG. 3). This step 450 corresponds to a part of the work amount control means.

  Next, the CPU proceeds to step 455, where the in-cylinder injection valve 28 and the port injection valve 23 are injected so as to inject the fuel of the in-cylinder injection amount fic and the port injection amount fip determined as described above. Then, the routine proceeds to step 495 to end the present routine tentatively. As described above, the CPU repeatedly executes the processes of steps 400 to 415, 420, 430, and 435 to 495 until time t10, and monitors steps 415 and 420.

  As a result, since the accelerator operation amount Accp is maintained at a small value Accp1 before time t10, the in-cylinder intake air amount Mc is maintained at a small value, and the target value VTt of the opening / closing timing of the intake valve 11 is set in the table MapVTt ( NE, Accp) is maintained at the value VT1 determined based on NE, and the actual opening / closing timing VT of the intake valve 11 is also maintained at the target value VT1.

  On the other hand, the basic fuel injection amount Fbase (= cylinder intake air amount Mc / target air-fuel ratio abyfr) is also maintained at a small value, and the injection ratio R (the basic injection described above) determined based on the table MapR (NE, Mc). The in-cylinder injection amount fic determined based on the ratio) and the basic fuel injection amount Fbase, and the duty ratio of the electromagnetic spill valve 33 are also maintained at a small value.

  Next, the case where the time t10 has arrived and the operating speed NE of the internal combustion engine 10 is low and the pressure Po of the engine oil generated by the oil pump 16 is less than the predetermined pressure β will be described. In this case, since the accelerator operation amount Accp maintained at the value Accp1 changes to a large value Accp2, the CPU determines “Yes” at steps 420 and 425, and proceeds to step 460 to be “0”. The value of the flag Z is changed / set to “1”.

  Next, the CPU proceeds to step 465 and clears elapsed time T counted by a timer (not shown) to “0”. Subsequently, the CPU proceeds to step 430, determines “Yes”, proceeds to step 470, and changes / sets the injection ratio R to “0”. Then, after executing the processing of steps 440 to 455, the routine proceeds to step 495, where the present routine is temporarily terminated.

  As a result, at time t10, the accelerator operation amount Accp has changed from a small value Accp1 to a large value Accp2 (because the change speed dAccp of the accelerator operation amount Accp has become equal to or greater than a predetermined speed α). The value VTt changes from the value VT1 to the value VT2 on the more advanced side (see the one-dot chain line in FIG. 6). Therefore, the opening / closing timing deviation dVT becomes a large positive value, and the variable intake timing device 15 operates in the direction of the arrow A of the broken line in FIG. That is, the actual opening / closing timing VT of the intake valve 11 starts to approach the value VT2 while the opening / closing timing deviation dVT approaches “0”.

  On the other hand, while the basic fuel injection amount Fbase also changes to a large value, the injection ratio R is changed to “0”, and the in-cylinder injection amount fic and the duty ratio of the electromagnetic spill valve 33 are changed and set to “0”. Is done. The port injection amount fip is determined to be the same value as the basic fuel injection amount Fbase.

  After time t10, since the value of the flag Z is “1”, the CPU determines “No” when it proceeds to step 415, and proceeds to step 475, where the elapsed time T (that is, time t10) is reached. It is determined whether or not the elapsed time from the deposit generation time T1 is smaller than the deposit generation time T1, and if “Yes” is determined, the process proceeds to step 480 where the absolute value of the switching timing deviation dVT (the degree of the difference) is a predetermined value. It is determined whether it is equal to or greater than γ (the predetermined degree). The deposit generation time T1 will be described in detail later.

  If any one of the conditions in steps 475 and 480 is not satisfied, the CPU proceeds to step 485 to change / set the value of the flag Z that was “1” to “0”. On the other hand, when all the conditions in steps 475 and 480 are satisfied, the CPU proceeds to step 430 and determines whether or not the value of the flag Z is “1”. That is, after time t10, as long as any one of the conditions in steps 475 and 480 is not satisfied, the CPU repeatedly executes the processes in steps 400 to 415, 475, 480, 430, 470 to 495, and step 475. , 480 are monitored.

  If the description is continued assuming that the condition of step 475 is satisfied, the condition of step 480 is not satisfied because the absolute value of the opening / closing timing deviation dVT that becomes smaller after time t10 becomes less than a predetermined value γ. During the period up to time t11, the value of the flag Z is maintained at “1”. A period in which the value of the flag Z is maintained at “1” in this way is referred to as a camshaft drive load reduction period.

  As a result, the injection ratio R, the in-cylinder injection amount fic, and the duty ratio of the electromagnetic spill valve 33 are maintained at “0” during the camshaft drive load reduction period (see steps 470, 440, and 450). On the other hand, the actual opening / closing timing VT of the intake valve 11 continues to approach the target value VT2 as shown by the solid line in FIG. The port injection amount fip is maintained at the same value as the basic fuel injection amount Fbase (see step 445).

  In this way, the in-cylinder injection amount fic and the duty ratio of the electromagnetic spill valve 33 are maintained at “0”, whereby the work amount in the pumping stroke of the high-pressure fuel pump 14 is maintained at a minimum value, and the camshaft The driving load is also maintained at a minimum value. Therefore, even when the engine oil pressure Po is smaller than the predetermined pressure β as described above, the actual opening / closing timing VT of the intake valve 11 changes from the value VT1 to the more advanced value VT2 with a large change speed. Since it approaches, it can quickly coincide with the target value VT2. Further, even during the camshaft drive load reduction period, the total amount of fuel combusted in the combustion chamber can be set to the basic fuel injection amount Fbase, so that the air-fuel ratio can be set to the target air-fuel ratio abyfr.

  Here, as shown by a broken line in FIG. 6, suppose that the injection ratio R is not set to “0” and is set to the basic injection ratio in the camshaft drive load reduction period. In this case, as the accelerator operation amount Accp changes from a small value Accp1 to a large value Accp2, the in-cylinder injection amount fic and the duty ratio change to values larger than the values before time t10 at time t10. The large value is maintained during the camshaft drive load reduction period.

  Therefore, the amount of work in the pumping stroke of the high-pressure fuel pump 14 is maintained at a large value, and the camshaft driving load is also maintained at a large value. Further, as described above, the pressure Po of the engine oil is smaller than the predetermined pressure β. Therefore, as shown by the broken line in FIG. 6, the actual opening / closing timing VT of the intake valve 11 approaches the value VT2 which is the target value because it approaches the advanced value VT2 from the value VT1 with a small change speed. Takes a long time. As described above, since the work amount in the intake stroke of the high-pressure fuel pump 14 is substantially “0” (see FIG. 3), the intake valve 11 in the intake stroke shown by the solid line and the broken line in FIG. The actual changing speed of the opening / closing timing VT is the same.

  As a result, the effect of increasing fresh air due to the generation of the static pressure wave from the intake passage toward the combustion chamber cannot be obtained sufficiently, and the internal combustion engine 10 is applied according to the increase in the accelerator operation amount Accp. It becomes difficult to execute acceleration of the vehicle with good response.

  On the other hand, according to the present embodiment, the actual opening / closing timing VT of the intake valve 11 can be quickly matched from the value VT1 to the value VT2. As a result, a static pressure wave is generated from the intake passage toward the combustion chamber, so that burned gas is prevented from flowing out from the combustion chamber to the intake passage, and the amount of fresh air sucked into the combustion chamber is quickly increased. Since it can be increased, the acceleration of the vehicle can be executed with good response in response to a sudden increase in the accelerator operation amount Accp.

  When the time t11 arrives, the absolute value of the opening / closing timing deviation dVT is less than the predetermined value γ, so the CPU makes a “No” determination at step 480 to proceed to step 485 to be “1”. The value of the flag Z is changed / set to “0” again. Thereafter, as before time t10, the injection ratio R is set again to the basic injection ratio, and when the actual opening / closing timing VT of the intake valve 11 coincides with the target value VT2, the oil passage switching mechanism Supply of engine oil to the advance chamber is stopped. The steps 415, 420, 425, 430, 435, 460, 465, 470, 475, 480, 485 described above correspond to a part of the injection ratio determining means.

  Here, the deposit generation time T1 (see step 475) will be additionally described. Generally, the temperature in the vicinity of the injection hole of the in-cylinder injection valve 28 tends to increase as the in-cylinder injection amount fic decreases. Further, when the in-cylinder injection amount fic decreases and the temperature in the vicinity of the injection hole of the in-cylinder injection valve 28 becomes excessively high, deposits are often generated in the injection hole of the in-cylinder injection valve 28.

  The deposit generation time T1 is the time from when the in-cylinder injection amount fic is changed to “0” until the generation of deposit in the injection hole of the in-cylinder injection valve 28 starts. The deposit generation time T1 is set so as to become shorter as the temperature near the injection hole of the in-cylinder injection valve 28 at the time when the in-cylinder injection amount fic is changed to “0”.

  After the time point when the change speed dAccp of the accelerator operation amount Accp reaches a predetermined speed α (that is, after time t10 in FIG. 6), the elapsed time T from the same point is not less than the deposit generation time T1 set as described above. In this case, the CPU makes a “No” determination at step 475 to proceed to step 485 to change / set the value of the flag Z, which was “1”, to “0”. The injection ratio R that has been obtained is returned to the basic injection ratio. As a result, an increase in the in-cylinder injection amount fic can suppress the temperature in the vicinity of the injection hole of the in-cylinder injection valve 28 from becoming excessively high, and deposits are generated in the injection hole of the in-cylinder injection valve 28. This can be suppressed. As a result, it is possible to suppress the occurrence of problems in the in-cylinder injection valve 28, such as clogging of the injection holes due to the generation of deposits.

  As described above, after time t10, when the elapsed time T from time t10 is equal to or longer than the deposit generation time T1, the opening / closing timing deviation dVT is “1” before the absolute value becomes less than the predetermined value γ. The value of the flag Z is changed and determined to “0” (that is, the injection ratio R that was “0” is returned to the basic injection ratio). That is, the end of the camshaft drive load reduction period is the time when the condition of one of the steps 475 and 480 where the condition is not satisfied is the earliest.

  As described above, the embodiment of the control device for an internal combustion engine according to the present invention generates the pressure of the fuel injected from the in-cylinder injection valve 28, the port injection valve 23, and the in-cylinder injection valve 28, and the intake. The high-pressure fuel pump 14 driven by the rotation of the camshaft 12, the electromagnetic spill valve 33 for adjusting the work amount of the high-pressure fuel pump 14 by adjusting the duty ratio, and the engine oil generated by driving the oil pump 16 The present invention is applied to an internal combustion engine having a variable intake timing device 15 that adjusts the actual opening / closing timing VT of the intake valve 11 by adjusting the relative phase angle of the intake camshaft 12 with respect to the crankshaft 20 using the pressure Po as a pressure source. .

  According to the above embodiment, the injection ratio R (= fic / (fic + fip)) is normally set to the basic injection ratio, and the in-cylinder injection amount fic and the port injection amount are based on the set injection ratio R. fip is determined, and the duty ratio of the electromagnetic spill valve 33 is adjusted to increase as the determined in-cylinder injection amount fic increases. On the other hand, the actual opening / closing timing VT of the intake valve 11 is controlled to coincide with the target value VTt of the opening / closing timing of the intake valve 11 determined based on the accelerator operation amount Accp.

  When the engine oil pressure Po is lower than the predetermined pressure β and the change speed dAccp of the accelerator operation amount Accp is equal to or higher than the predetermined speed α, the injection ratio R is set to the basic injection ratio. Instead of being changed and set to “0”, the in-cylinder injection amount fic and the duty ratio of the electromagnetic spill valve 33 become “0”.

  Here, the camshaft drive load, which is the load applied to the intake camshaft 12 to drive the high-pressure fuel pump 14, is such that the smaller the in-cylinder injection amount fic and the duty ratio of the electromagnetic spill valve 33, the smaller the camshaft drive load. Since the amount of work in the fuel pumping stroke is small, it is small. Therefore, the camshaft driving load is minimized by setting the injection ratio R to “0” as described above.

  Therefore, even when the engine oil pressure Po is less than the predetermined pressure β, the camshaft driving load is minimized, so that the actual opening / closing timing VT of the intake valve 11 has a large change speed and the target value. The value VTt can be approached. As a result, when the accelerator operation amount Accp suddenly increases, the actual opening / closing timing VT of the intake valve 11 can quickly coincide with the target value VTt determined as a more advanced value, and the combustion chamber Since the amount of fresh air inhaled can be quickly increased, acceleration of the vehicle can be executed in a responsive manner.

  The present invention is not limited to the above embodiment, and various modifications can be employed within the scope of the present invention. For example, in the above embodiment, when the engine oil pressure Po is less than the predetermined pressure β, and the change speed dAccp of the accelerator operation amount Accp is equal to or higher than the predetermined speed α, the injection ratio R As a value (the first ratio) in which the ratio of the in-cylinder injection amount fic is smaller than the injection ratio, it is configured to be changed / set to “0”, but instead of the first ratio, The basic injection ratio may be changed and set to a corrected value. When correcting the basic injection ratio, for example, the correction may be performed by multiplying the basic injection ratio by the correction coefficient K, or may be corrected by subtracting the correction value L from the basic injection ratio. In this case, it is preferable that the correction coefficient K and the correction value L are determined so that the ratio of the in-cylinder injection amount fic in the injection ratio R decreases as the absolute value of the opening / closing timing deviation dVT increases. It is. Specifically, the correction coefficient K is a value between “0” and “1”, and is determined to be smaller as the absolute value of the opening / closing timing deviation dVT is larger. The correction value L is a value between “0” and “1”, and is determined so as to increase as the absolute value of the opening / closing timing deviation dVT increases.

  Further, the step (hereinafter referred to as “step 490”) for making the same determination as step 425 for determining whether or not the pressure Po of the engine oil is less than the predetermined pressure β is referred to as the routine of FIG. It may be added during the steps 475 and 480. When the engine oil pressure Po is large, even when the camshaft driving load is large, the actual opening / closing timing VT of the intake valve 11 can approach the target value VTt of the opening / closing timing of the intake valve 11 with a large change speed. . Therefore, in this case, the necessity of setting the injection ratio R to “0” is small. According to the above configuration, when the pressure Po of the engine oil becomes equal to or higher than the predetermined pressure β after the change speed dAccp of the accelerator operation amount Accp becomes equal to or higher than the predetermined speed α (see time t10 in FIG. 6). When the CPU of the electric control device 50 proceeds to step 490 inserted between steps 475 and 480, it determines “No”, proceeds to step 485, and sets the value of the flag Z that was “1”. It is changed and set to “0” (therefore, the injection ratio R that was “0” is returned to the basic injection ratio). Thereby, setting the injection ratio R to “0” unnecessarily is suppressed, and the opportunity to use the basic injection ratio as the injection ratio R can be increased. In this case, the end of the camshaft drive load reduction period is the time when the condition of any one of the steps 475, 490, and 480 where the condition is unsuccessful is unsatisfied.

  In addition, in the above-described embodiment, whether or not deposit is generated in the injection hole of the in-cylinder injection valve 28 is determined based on the elapsed time T from when the target value VTt of the opening / closing timing of the intake valve 11 suddenly changes. The determination is made based on whether or not the deposit generation time is equal to or longer than T1, but instead, for example, the same determination is made based on the concentration of NOx contained in the exhaust gas, which is closely related to deposit generation. You may do it.

1 is a schematic configuration diagram of a valve operating system for an internal combustion engine to which a control device according to an embodiment of the present invention is applied. 1 is a schematic configuration diagram of a fuel supply system for an internal combustion engine to which a control device according to an embodiment of the present invention is applied. It is a figure for demonstrating the relationship between the work amount of a high pressure fuel pump, the in-cylinder injection amount, and the duty ratio of an electromagnetic spill valve. FIG. 3 is a flowchart showing a first half of a program for determining in-cylinder injection amount and port injection amount and executing in-cylinder injection and port injection, which is executed by the CPU of the electric control device shown in FIG. 2. FIG. 3 is a flowchart showing a second half of a program for determining in-cylinder injection amount and port injection amount, and executing in-cylinder injection and port injection, which is executed by the CPU of the electric control device shown in FIG. 2. It is the time chart which showed the change of the various variables when the control apparatus which concerns on embodiment of this invention performs control.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Internal combustion engine, 11 ... Intake valve, 12 ... Intake camshaft, 14 ... High pressure fuel pump, 15 ... Variable intake timing device, 16 ... Oil pump, 20 ... Crankshaft, 23 ... Port injection valve, 28 ... In-cylinder injection Valve, 33 ... electromagnetic spill valve, 50 ... electric control device.

Claims (6)

An in-cylinder injection mechanism for injecting fuel into the combustion chamber of the internal combustion engine;
A port injection mechanism for injecting fuel into an intake passage upstream of the intake valve of the internal combustion engine;
A first pressure generating mechanism for generating a pressure of the liquid;
The intake valve or exhaust valve corresponding to the relative phase angle between the camshaft that drives the intake valve or the exhaust valve of the internal combustion engine and the crankshaft of the internal combustion engine using the pressure of the liquid. A valve opening / closing timing adjustment mechanism for adjusting the opening / closing timing;
A second pressure generating mechanism that is driven by rotation of the camshaft and generates a pressure of fuel injected by the in-cylinder injection mechanism;
A work amount adjusting mechanism for adjusting the work amount of the second pressure generating mechanism;
Applied to an internal combustion engine with
Target value determining means for determining a valve opening / closing timing target value that is a target value of the opening / closing timing of the intake valve or the exhaust valve;
Valve opening / closing timing control means for controlling the valve opening / closing timing adjustment mechanism so that the actual opening / closing timing of the intake valve or the exhaust valve approaches the valve opening / closing timing target value;
A work amount control means for controlling the work amount adjusting mechanism so that the work amount of the second pressure generating mechanism is adjusted in accordance with an in-cylinder injection amount that is an amount of fuel injected by the in-cylinder injection mechanism;
An injection ratio determination means for determining an in-cylinder injection amount and an injection ratio, which is a ratio of the amount of fuel injected by the port injection mechanism, as a basic injection ratio determined based on an operating state of the internal combustion engine;
An internal combustion engine control apparatus comprising:
The injection ratio determining means includes
When the pressure of the liquid is less than a predetermined pressure and the change speed of the valve opening / closing timing target value is equal to or higher than the first speed, the basic injection ratio is used instead of the basic injection ratio. A control apparatus for an internal combustion engine configured to determine a first ratio that is a value at which the ratio of the in-cylinder injection amount is smaller than the first ratio. The control apparatus for an internal combustion engine according to claim 1,
The injection ratio determining means, as the first ratio,
A control device for an internal combustion engine configured to use a value at which a ratio of the in-cylinder injection amount is "0". The fuel injection amount control device for an internal combustion engine according to claim 1 or 2,
The injection ratio determining means includes
When the degree of difference between the actual opening / closing timing of the intake valve or the exhaust valve and the valve opening / closing timing target value is less than a predetermined level, the injection ratio is returned to the basic injection ratio. Control device for internal combustion engine. The fuel injection amount control device for an internal combustion engine according to any one of claims 1 to 3,
The injection ratio determining means includes
When it is determined that deposit is generated in the injection hole of the in-cylinder injection mechanism due to a decrease in the in-cylinder injection amount due to the change of the injection ratio from the basic injection ratio to the first ratio, A control apparatus for an internal combustion engine configured to return an injection ratio to the basic injection ratio. The fuel injection amount control device for an internal combustion engine according to any one of claims 1 to 4,
The injection ratio determining means includes
A control device for an internal combustion engine configured to return the injection ratio to the basic injection ratio when the pressure of the liquid is equal to or higher than the predetermined pressure. The fuel injection amount control device for an internal combustion engine according to any one of claims 1 to 5,
The target value determining means includes
A valve opening / closing timing target value for the intake valve is determined, and a valve opening / closing timing target value for the intake valve is determined so as to become a value on a more advanced side as the accelerator operation amount is larger,
The injection ratio determining means includes
When the pressure of the liquid is less than the predetermined pressure and the change speed of the accelerator operation amount is equal to or higher than the second speed, the injection ratio is changed to the first ratio instead of the basic injection ratio. A control device for an internal combustion engine configured to determine.

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