JP4274002B2 - Internal combustion engine control system - Google Patents

Description

  The present invention relates to a control system for an internal combustion engine, and in particular, an intake passage injection valve that injects fuel into an intake passage, a cylinder injection valve that directly injects fuel into a cylinder, a lift amount of the intake valve, and / or The present invention relates to a control system for an internal combustion engine including a variable valve mechanism that changes valve timing.

  2. Description of the Related Art Conventionally, an internal combustion engine that includes both an intake passage injection valve that injects fuel into an intake passage and an in-cylinder injection valve that directly injects fuel into a cylinder is known.

  In such an internal combustion engine, when a supercharger is further provided, in the high boost pressure region, the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount is increased, and the total fuel injection amount is increased. A technique for reducing the ratio of the fuel injection amount from the in-cylinder injection valve is disclosed (for example, see Patent Document 1).

An internal combustion engine having a variable valve mechanism that changes the lift amount and / or valve timing of an intake valve has been developed. In such an internal combustion engine, when the lift amount and / or the valve timing of the intake valve is changed, the flow velocity at which the intake air flows into the cylinder (hereinafter referred to as the intake air inflow velocity) changes.
JP 11-351041 A Japanese Patent No. 2668680 JP 2002-364409 A JP 2001-20837 A

  By the way, a technique for more suitably controlling an internal combustion engine that includes both an intake valve injection valve and a cylinder injection valve, and further includes a variable valve mechanism that changes the lift amount and / or valve timing of the intake valve. Not proposed. For example, in such an internal combustion engine, as the intake flow rate is increased by changing the lift amount and / or valve timing of the intake valve by a variable valve mechanism, the intake valve is injected from the intake passage injection valve and is injected into the cylinder together with the intake air. The fuel that has flowed into the bore tends to adhere to the bore wall surface. As a result, exhaust characteristics and fuel consumption may be deteriorated.

  On the other hand, as the intake valve inflow speed becomes slower by changing the lift amount and / or the valve timing of the intake valve by the variable valve mechanism, the air flow in the cylinder caused by the intake air (so-called swirl flow or tumble flow) Becomes weak and it becomes difficult for the fuel injected from the in-cylinder injection valve to mix with the intake air in the cylinder. As a result, the combustion state deteriorates, and the exhaust characteristics and fuel consumption may deteriorate as described above.

  The present invention has been made in view of the above-described problems, and includes a variable valve mechanism that includes both an intake valve injection valve and a cylinder injection valve, and further changes the lift amount and / or valve timing of the intake valve. It is an object of the present invention to provide a technique capable of more suitably controlling an internal combustion engine that is also provided.

According to a first aspect of the present invention, in an internal combustion engine provided with an intake valve injection valve, an in-cylinder injection valve, and a variable valve mechanism, intake by changing the lift amount and / or valve timing of the intake valve by the variable valve mechanism The ratio of the fuel injection amount from the intake passage injection valve and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount are changed according to the change in the inflow speed.

More specifically, the control system for an internal combustion engine according to the present invention is:
An intake passage injection valve for injecting fuel into the intake passage;
An in-cylinder injection valve that directly injects fuel into the cylinder;
A variable valve mechanism that changes the lift amount and / or valve timing of the intake valve;
The ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, which is the sum of the fuel injection amount from the intake passage injection valve and the fuel injection amount from the in-cylinder injection valve, and the in-cylinder Fuel injection amount ratio changing means for changing the ratio of the fuel injection amount from the injection valve,
The fuel injection amount ratio changing means increases the flow rate when the intake air flows into the cylinder by changing the lift amount and / or valve timing of the intake valve by the variable valve mechanism. The ratio of the fuel injection amount from the intake valve in the intake passage to the amount is lowered, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is increased.

  In the present invention, the fuel injection amount from the intake passage injection valve is decreased and the fuel injection amount from the in-cylinder injection valve is increased as the intake flow rate is increased. Therefore, it is possible to suppress the amount of fuel that is injected from the intake valve injection valve and that adheres to the bore wall surface along with the intake air flow when flowing into the cylinder. In addition, as the intake air inflow speed increases, a stronger air flow is generated in the cylinder, so that the fuel injected from the in-cylinder injection valve is easily mixed with the intake air. Therefore, even if the fuel injection amount from the in-cylinder injection valve increases, the combustion state is not easily deteriorated.

  On the other hand, the fuel injection amount from the intake passage injection valve is increased and the fuel injection amount from the in-cylinder injection valve is decreased as the intake flow rate becomes slower. That is, the fuel injection amount from the in-cylinder injection valve decreases as the airflow in the cylinder becomes weaker. Therefore, it is possible to suppress the deterioration of the combustion state because the fuel injected from the in-cylinder injection valve is not sufficiently mixed with the intake air. In addition, the fuel injected from the intake passage injection valve is more easily mixed with the intake air than the fuel injected from the in-cylinder injection valve. Therefore, even if the fuel injection amount from the intake passage injection valve increases, the combustion state Hard to get worse.

  As described above, according to the present invention, it is possible to suppress the adhesion of fuel to the bore wall surface and the deterioration of the combustion state, and as a result, it is possible to suppress the deterioration of exhaust characteristics and fuel consumption.

  In the present invention, as the lift amount of the intake valve is reduced by the variable valve mechanism, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is lowered, and the in-cylinder injection to the total fuel injection amount is reduced. The ratio of the fuel injection amount from the valve may be increased. In other words, as the lift amount of the intake valve is increased by the variable valve mechanism, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is increased, and the in-cylinder injection valve to the total fuel injection amount is increased. The ratio of the amount of fuel injection from may be lowered.

  Further, when the valve opening timing of the intake valve is retarded from the intake stroke top dead center by the variable valve mechanism, the fuel injection amount from the intake valve in the intake passage relative to the total fuel injection amount increases as the delay amount increases. The ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount may be increased. In other words, when the valve opening timing of the intake valve is retarded from the intake stroke top dead center by the variable valve mechanism, the fuel from the intake passage injection valve relative to the total fuel injection amount decreases as the retardation amount decreases. The ratio of the injection amount may be increased, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount may be decreased.

As the intake valve lift amount decreases, the intake air inflow speed increases. In addition, when the opening timing of the intake valve is retarded from the top dead center of the intake stroke, the larger the retard amount, the more the negative pressure in the cylinder is opened, and the intake valve is opened. Speed increases. Therefore, according to the control as described above, the fuel injection amount from the intake passage injection valve is decreased and the fuel injection amount from the in-cylinder injection valve is increased as the intake flow rate is increased. Further, as the intake air inflow speed becomes slower, the fuel injection amount from the intake passage injection valve is increased, and the fuel injection amount from the in-cylinder injection valve is decreased.

  In the present invention, when the lift amount of the intake valve is equal to or less than the specified lift amount, the fuel injection from the intake valve injection valve with respect to the total fuel injection amount is performed as compared with the case where the lift amount of the intake valve is larger than the specified lift amount. The ratio of the amount may be decreased, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount may be increased.

  Further, when the opening timing of the intake valve is retarded from the intake stroke top dead center, compared to the case where the opening timing of the intake valve is advanced before the intake stroke top dead center, the total fuel injection amount is The ratio of the fuel injection amount from the intake passage injection valve may be lowered, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount may be increased.

  Also by the control as described above, the fuel injection amount from the intake valve injection valve is decreased and the fuel injection amount from the in-cylinder injection valve is increased as the intake flow rate is increased. Further, as the intake air inflow speed becomes slower, the fuel injection amount from the intake passage injection valve is increased, and the fuel injection amount from the in-cylinder injection valve is decreased.

    Note that the specified lift amount means that when the lift amount of the intake valve is less than or equal to the specified lift amount, the intake inflow speed becomes excessively high, and the fuel injection amount from the injection valve in the intake passage does not decrease. It may be a value at which it can be determined that the amount of fuel injected from the in-passage injection valve and adhering to the bore wall surface exceeds the allowable amount. Further, when the lift amount of the intake valve becomes larger than the specified lift amount, if the intake flow rate becomes excessively slow and the fuel injection amount from the in-cylinder injection valve does not decrease, the fuel injected from the in-cylinder injection valve May be a value that can be determined to cause deterioration of the combustion state by not being sufficiently mixed with intake air in the cylinder.

  In the present invention, when at least one of the intake passage temperature detection means for detecting the temperature in the intake passage and the in-cylinder temperature detection means for detecting the temperature in the cylinder is further provided, the intake passage temperature detection When the temperature in the intake passage detected by the means is less than or equal to the specified intake passage temperature, or when the temperature in the cylinder detected by the in-cylinder temperature detection means is less than or equal to the specified in-cylinder temperature, Control of the ratio of the fuel injection amount from the intake passage injection valve and the ratio of the fuel injection amount from the in-cylinder injection valve in accordance with changes in the intake flow rate due to changes in the intake valve lift amount and / or valve timing May be executed.

  As the temperature in the intake passage and the cylinder decreases, the fuel injected from each fuel injection valve is less likely to be atomized (or vaporized). Therefore, the amount of fuel adhering to the bore wall surface is likely to increase, and the combustion state is likely to deteriorate due to insufficient mixing of fuel and intake air. Therefore, when the temperature in the intake passage is equal to or lower than the specified intake passage temperature, or when the temperature in the cylinder is equal to or lower than the specified in-cylinder temperature, the effect can be further obtained by performing the above control. For example, it is possible to suppress deterioration of exhaust characteristics and fuel consumption when cold.

  The prescribed intake passage temperature and the prescribed in-cylinder temperature are such that fuel atomization (or vaporization) becomes difficult as the amount of fuel adhering to the bore wall surface increases and the combustion state deteriorates. And the temperature in the cylinder are preferable.

According to a second aspect of the present invention, in an internal combustion engine having an intake passage injection valve, an in-cylinder injection valve, and a variable valve mechanism, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount and the in-cylinder injection The lift amount and / or valve timing of the intake valve is changed in order to change the intake air inflow speed in accordance with the change in the ratio of the fuel injection amount from the valve.

More specifically, the control system for an internal combustion engine according to the present invention is:
An intake passage injection valve for injecting fuel into the intake passage;
An in-cylinder injection valve that directly injects fuel into the cylinder;
A variable valve mechanism that changes the lift amount and / or valve timing of the intake valve;
The ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, which is the sum of the fuel injection amount from the intake passage injection valve and the fuel injection amount from the in-cylinder injection valve, and the in-cylinder Fuel injection amount ratio changing means for changing the ratio of the fuel injection amount from the injection valve,
The fuel injection amount ratio changing means increases the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is low. The variable valve mechanism changes the lift amount and / or the valve timing of the intake valve so that the flow rate when the intake air flows into the cylinder becomes slower as the cylinder is released.

  In the present invention, the intake inflow speed is reduced as the fuel injection amount from the intake valve injection valve increases and the fuel injection amount from the in-cylinder injection valve decreases. Therefore, it is possible to suppress the amount of fuel that is injected from the intake valve injection valve and that adheres to the bore wall surface along with the intake air flow when flowing into the cylinder.

  On the other hand, as the fuel injection amount from the intake passage injection valve decreases and the fuel injection amount from the in-cylinder injection valve increases, the intake flow rate is increased. In other words, the airflow in the cylinder becomes stronger as the fuel injection amount from the in-cylinder injection valve increases. Therefore, it is possible to suppress the deterioration of the combustion state because the fuel injected from the in-cylinder injection valve is not sufficiently mixed with the intake air.

  As described above, according to the present invention, it is possible to suppress the adhesion of fuel to the bore wall surface and the deterioration of the combustion state, and as a result, it is possible to suppress the deterioration of exhaust characteristics and fuel consumption.

  In the present invention, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is increased, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is decreased. The lift amount may be increased. In other words, the higher the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount, the higher the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount. The amount may be reduced.

  When the intake valve opening timing is after the top dead center of the intake stroke, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is increased, and the in-cylinder injection valve to the total fuel injection amount is increased. The valve opening timing of the intake valve may be advanced as the ratio of the fuel injection amount from the lower is reduced. In other words, when the opening timing of the intake valve is after the top dead center of the intake stroke, the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount is lowered, and the in-cylinder to the total fuel injection amount is reduced. The valve opening timing of the intake valve may be retarded as the ratio of the fuel injection amount from the injection valve is increased.

  As the lift amount of the intake valve increases, the intake inflow speed decreases. Further, when the opening timing of the intake valve is after the top dead center of the intake stroke, the intake inflow speed becomes slower as the opening timing of the intake valve advances. Therefore, according to the control as described above, the intake inflow speed is slowed as the fuel injection amount from the intake passage injection valve increases and the fuel injection amount from the in-cylinder injection valve decreases. Further, as the fuel injection amount from the intake passage injection valve decreases and the fuel injection amount from the in-cylinder injection valve increases, the intake inflow speed is increased.

  In the present invention, when the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount is equal to or greater than the specified ratio, the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount is the specified ratio. The lift amount of the intake valve and / or the valve timing may be changed so that the intake air inflow speed becomes slower than that in the case of less than the above.

  Even with such control, the intake inflow speed is reduced as the fuel injection amount from the in-cylinder injection valve increases and the fuel injection amount from the in-cylinder injection valve decreases. Further, as the fuel injection amount from the intake passage injection valve decreases and the fuel injection amount from the in-cylinder injection valve increases, the intake inflow speed is increased.

  The prescribed ratio means that when the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is equal to or greater than the prescribed ratio, the fuel injection amount from the intake passage injection valve is excessively increased. When the inflow speed is not slowed down, the value may be determined so that the amount of fuel injected from the intake valve injection valve and adhering to the bore wall surface is larger than the allowable amount. In addition, when the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount is less than the specified ratio, the fuel injection amount from the in-cylinder injection valve is excessively increased, and the intake inflow speed is not increased. The fuel injection from the in-cylinder injection valve may be a value that can be determined to cause deterioration of the combustion state because the fuel is not sufficiently mixed with the intake air in the cylinder.

  In the present invention, when changing the lift amount and / or valve timing of the intake valve in order to change the intake air inflow speed, the intake air amount flowing into the cylinder is hardly changed before and after the change. It is preferable to change the valve closing timing.

  Also in the present invention, when at least one of the intake passage temperature detection means for detecting the temperature in the intake passage and the in-cylinder temperature detection means for detecting the temperature in the cylinder is further provided, the intake passage As described above, when the temperature in the intake passage detected by the internal temperature detection means is not more than the specified intake passage temperature, or when the temperature in the cylinder detected by the in-cylinder temperature detection means is not more than the specified in-cylinder temperature. As described above, the lift amount of the intake valve and / or the intake valve lift amount to obtain the intake flow rate according to the change in the ratio of the fuel injection amount from the intake valve injection valve and the fuel injection amount from the cylinder injection valve to the total fuel injection amount, and / or Valve timing control may be executed.

  As in the case of the first invention, the specified intake passage temperature and specified in-cylinder temperature here also increase the amount of fuel adhering to the bore wall surface and deteriorate the combustion state so that the fuel atomizes (or vaporizes). It is preferable to set the temperature in the intake passage and the temperature in the cylinder at which it becomes difficult to achieve the above.

  When the temperature in the intake passage is equal to or lower than the specified intake passage temperature, or when the temperature in the cylinder is equal to or lower than the specified in-cylinder temperature, the effect can be obtained more by performing the above control. For example, it is possible to suppress deterioration of exhaust characteristics and fuel consumption when cold.

  According to the control system for an internal combustion engine of the present invention, there is provided an internal combustion engine that includes an intake valve injection valve, a cylinder injection valve, a variable valve mechanism that changes the lift amount and / or valve timing of the intake valve. It can control suitably.

  Hereinafter, specific embodiments of a control system for an internal combustion engine according to the present invention will be described with reference to the drawings.

<Schematic configuration of internal combustion engine and its intake / exhaust system>
First, a first embodiment of the control system for an internal combustion engine according to the present invention will be described. Here, the case where the present invention is applied to a gasoline engine for driving a vehicle will be described as an example. FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine and its intake / exhaust system according to the present embodiment.

  The internal combustion engine 1 has a cylinder 2, and a piston 3 is slidably provided in the cylinder 2. An intake port 5 and an exhaust port 6 are opened in the combustion chamber 4 in the upper part of the cylinder 2. The intake port 5 is connected to the intake passage 7, and the exhaust port 6 is connected to the exhaust passage 8.

  The openings of the intake port 5 and the exhaust port 6 to the combustion chamber 4 are opened and closed by an intake valve 9 and an exhaust valve 10, respectively. The intake valve 9 is provided with a variable valve mechanism 11 that variably controls the lift amount and valve timing.

  The intake passage 7 is provided with an in-port injection valve 12 that injects fuel into the intake port 5. An in-cylinder injection valve 13 that directly injects fuel into the cylinder is provided in the upper part of the cylinder 2. A spark plug 14 for igniting the air-fuel mixture protrudes from the combustion chamber 4.

  The intake port 5 is provided with an in-port temperature sensor 21 that detects the temperature in the intake port 5. The cylinder 2 is provided with a water temperature sensor 22 that detects the cooling water temperature in the water jacket of the cylinder 2.

  The internal combustion engine 1 configured as described above is provided with an ECU 20 for controlling the internal combustion engine 1. The ECU 20 is a unit that controls the operation state of the internal combustion engine 1 in accordance with the operation conditions of the internal combustion engine 1 and the request of the driver. Various sensors such as an in-port temperature sensor 21 and a water temperature sensor 22 are connected to the ECU 20 via electric wiring, and these output signals are input to the ECU 20. Then, the ECU 20 estimates the temperature in the cylinder 2 from the detection value of the water temperature sensor 22.

  The ECU 20 is electrically connected to a variable valve mechanism 11, an in-port injection valve 12, an in-cylinder injection valve 13, a spark plug 14, and the like, and these can be controlled.

<Fuel injection control from in-port injection valve and in-cylinder injection valve>
Next, fuel injection control from the in-port injection valve 12 and the in-cylinder injection valve 13 according to the present embodiment will be described with reference to FIG. FIG. 2A shows the ratio of the fuel injection amount from the in-port injection valve 12 to the total fuel injection amount which is the sum of the fuel injection amount from the in-port injection valve 12 and the fuel injection amount from the in-cylinder injection valve 13. (Hereinafter referred to as the in-port fuel injection rate) and the amount of delay from the intake stroke top dead center when the valve opening timing of the intake valve 9 is retarded from the intake stroke top dead center ( Hereinafter, it is simply referred to as a valve opening timing retardation amount) and a graph showing the relationship between the lift amount of the intake valve 9. FIG. 2B shows the ratio of the fuel injection amount from the in-cylinder injection valve 13 to the total fuel injection amount (hereinafter referred to as the in-cylinder fuel injection rate), the valve opening timing retardation amount of the intake valve 9 and the intake air. It is a graph which shows the relationship with the lift amount of the valve. 2A and 2B, the vertical axis represents the lift amount of the intake valve 9, and the horizontal axis represents the valve opening timing retardation amount of the intake valve 9.

  When the lift amount and / or valve timing of the intake valve 9 is changed, the intake inflow speed changes according to the change. Specifically, the intake air inflow speed increases as the lift amount of the intake valve 9 decreases. When the opening timing of the intake valve 9 is after the top dead center of the intake stroke, the intake inflow speed increases as the valve opening timing retard amount increases.

  Therefore, in this embodiment, as shown in FIG. 2, the smaller the lift amount of the intake valve 9, the lower the in-port fuel injection rate and the higher the in-cylinder fuel injection rate. When the valve opening timing of the intake valve 9 is retarded from the intake stroke top dead center, the in-port fuel injection rate is lowered and the in-cylinder fuel injection rate is increased as the valve opening timing retard amount is increased.

  By controlling the ratio of the fuel injection amount from each of the fuel injection valves 12 and 13 in this way, the fuel injection amount from the in-port injection valve 12 is decreased as the intake air inflow speed becomes faster. The fuel injection amount is increased. Further, as the intake air inflow speed becomes slower, the fuel injection amount from the in-port injection valve 12 is increased, and the fuel injection amount from the in-cylinder injection valve 13 is decreased.

  As a result, the amount of fuel injected from the in-port injection valve 12 and adhering to the flow of intake air when flowing into the cylinder 2 and adhering to the bore wall surface can be suppressed. Moreover, it can suppress that a combustion state deteriorates because the fuel injected from the cylinder injection valve 13 is not fully mixed with intake air.

<Fuel injection ratio control flow>
Here, a control routine for controlling the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, the ECU 20 first reads the lift amount and valve opening timing of the intake valve 9 in the current operating state of the internal combustion engine 1 in S101.

  Next, the ECU 20 proceeds to S102, and determines whether or not the opening timing of the intake valve 9 is retarded from the intake stroke top dead center. If an affirmative determination is made in S102, the ECU 20 proceeds to S103, and if a negative determination is made, the ECU 20 proceeds to S104.

  In S103, the ECU 20 calculates a valve opening timing retard amount from the valve opening timing of the intake valve 9 read in S101, and substitutes the valve opening timing retard amount and the lift amount of the intake valve 9 read in S101 into a map. Thus, a target in-port fuel injection rate (hereinafter referred to as target port fuel injection rate) and a target in-cylinder fuel injection rate (hereinafter referred to as target in-cylinder fuel injection rate) are derived. The map here is the relationship between the in-port fuel injection rate, the valve opening timing retard amount of the intake valve 9 and the lift amount of the intake valve 9, as shown in FIG. The relationship between the in-cylinder fuel injection rate, the valve opening timing retard amount of the intake valve 9 and the lift amount of the intake valve 9 as shown in b) is determined in advance by experiments or the like, and is stored in the ECU 20. It is a thing. If one of the in-port fuel injection rate and the in-cylinder fuel injection rate is determined by the map, the other is inevitably determined. After deriving the target port fuel injection rate and the target in-cylinder fuel injection rate, the ECU 20 proceeds to S105.

  On the other hand, in S104, the ECU 20 derives the target port fuel injection rate and the target cylinder fuel injection rate by substituting the lift amount of the intake valve 9 read in S101 into a map different from the map of S105. This map is a map that defines the relationship between the in-port fuel injection rate and the lift amount of the intake valve 9 when the opening timing of the intake valve 9 is before the top dead center of the intake stroke, or the in-cylinder fuel injection rate These maps define the relationship with the lift amount of the intake valve 9. According to these maps, as in the cases (a) and (b) of FIG. 2, the smaller the lift amount of the intake valve 9, the smaller the fuel injection in the port. The rate is lowered and the in-cylinder fuel injection rate is raised. The map is also determined in advance by experiments or the like and stored in the ECU 20. After deriving the target port fuel injection rate and the target in-cylinder fuel injection rate, the ECU 20 proceeds to S105.

  In S105, the ECU 20 changes the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 based on the target in-port fuel injection rate and the target in-cylinder fuel injection rate derived in S103 or S104. That is, the fuel injection amount from each fuel injection valve 12, 13 is determined.

  Next, the ECU 20 proceeds to S106, executes fuel injection from each of the fuel injection valves 12, 13, and temporarily ends the execution of this routine.

  According to the control routine described above, the ratio of the fuel injection amount from each of the fuel injection valves 12 and 13 can be controlled more appropriately according to the intake air inflow speed, and as a result, deterioration of exhaust characteristics and fuel consumption can be suppressed. It becomes possible to do. That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

<Modification>
In the present embodiment, the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 may be controlled by the control routine shown in FIG. FIG. 4 is a flowchart showing a modification of the control routine for controlling the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 according to the present embodiment. Since S101 to S106 shown in FIG. 4 are the same as those in FIG. 2 described above, only S201 and S202 different from FIG. 2 will be described.

  In this routine, first, in S201, the ECU 20 determines whether or not the temperature in the intake port 5 detected by the in-port temperature sensor 21 is equal to or lower than the specified in-port temperature T1. If an affirmative determination is made in S201, the ECU 20 proceeds to S101, and if a negative determination is made, the ECU 20 proceeds to S202.

  In S202, the ECU 20 determines whether or not the temperature in the cylinder 2 estimated from the detection value of the water temperature sensor is equal to or lower than the specified in-cylinder temperature T2. If an affirmative determination is made in S202, the ECU 20 proceeds to S101, and if a negative determination is made, the ECU 20 proceeds to S106.

  Here, the specified port internal temperature T1 and the specified in-cylinder temperature T2 are temperatures at which it becomes difficult to atomize (or vaporize) the fuel and easily increase the amount of fuel adhering to the bore wall surface and deteriorate the combustion state. In this case, the value is predetermined by experiment or the like.

  According to such a control routine, when the temperature in the intake port 5 or the cylinder 2 is low and it becomes difficult to atomize (or vaporize) the fuel, the amount of fuel adhering to the bore wall surface or the combustion state is increased. Deterioration can be suppressed. For this reason, it is possible to suppress deterioration of exhaust characteristics and fuel consumption when cold.

  Next, a second embodiment of the control system for an internal combustion engine according to the present invention will be described. In addition, since the schematic structure of the internal combustion engine and its intake / exhaust system according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted.

<Fuel injection ratio control flow>
Here, a control routine for controlling the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, first, in S301, the ECU 20 reads the lift amount of the intake valve 9 in the current operating state of the internal combustion engine 1.

  Next, the ECU 20 proceeds to S302, and determines whether or not the lift amount of the intake valve 9 is equal to or less than a specified lift amount L0. If an affirmative determination is made in S302, the ECU 20 proceeds to S303, and if a negative determination is made, the ECU 20 proceeds to S304.

  In S303, the ECU 20 lowers the in-port fuel injection rate and increases the in-cylinder fuel injection rate as compared to the case where the lift amount of the intake valve 9 is larger than the specified lift amount L0. Thereafter, the ECU 20 proceeds to S305.

  On the other hand, in S304, the ECU 20 increases the in-port fuel injection rate and decreases the in-cylinder fuel injection rate as compared with the case where the lift amount of the intake valve 9 is equal to or less than the specified lift amount L0. Thereafter, the ECU 20 proceeds to S305.

  In S305, the ECU 20 executes fuel injection from each of the fuel injection valves 12 and 13, and temporarily ends the execution of this routine.

  According to the routine described above, the fuel injection amount from the in-port injection valve 12 decreases as the lift amount of the intake valve 9 decreases, that is, the intake inflow speed increases, and the fuel injection amount from the in-cylinder injection valve 13 decreases. Is increased. Further, as the intake air inflow speed becomes slower, the fuel injection amount from the in-port injection valve 12 is increased, and the fuel injection amount from the in-cylinder injection valve 13 is decreased.

  As a result, the amount of fuel injected from the in-port injection valve 12 and adhering to the flow of intake air when flowing into the cylinder 2 and adhering to the bore wall surface can be suppressed. Moreover, it can suppress that a combustion state deteriorates because the fuel injected from the cylinder injection valve 13 is not fully mixed with intake air.

  Therefore, according to the present embodiment, it is possible to suppress deterioration of exhaust characteristics and fuel consumption. That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

  Note that the specified lift amount L0 according to the present embodiment is that when the lift amount of the intake valve 9 becomes equal to or less than the specified lift amount L0, the intake inflow speed becomes excessively high, and the fuel injection amount from the in-port injection valve 12 becomes smaller. When not decreasing, the value may be determined so that the amount of fuel injected from the in-port injection valve 12 and adhering to the bore wall surface is larger than the allowable amount. Further, when the lift amount of the intake valve 9 becomes larger than the specified lift amount L0, the intake inflow speed becomes excessively slow, and if the fuel injection amount from the in-cylinder injection valve 13 does not decrease, the in-cylinder injection valve 13 It may be a value at which it can be determined that the injected fuel is not sufficiently mixed with the intake air in the cylinder 2 to deteriorate the combustion state.

  Similarly to the above-described modification of the first embodiment, when the temperature in the intake port 5 is equal to or lower than the specified port internal temperature T1, or when the temperature in the cylinder 2 is equal to or lower than the specified in-cylinder temperature T2, FIG. A control routine may be executed. In such a case, it is possible to suppress deterioration of exhaust characteristics and fuel consumption during cold.

  Next, a third embodiment of the control system for an internal combustion engine according to the present invention will be described. In addition, since the schematic structure of the internal combustion engine and its intake / exhaust system according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted.

<Fuel injection ratio control flow>
Here, a control routine for controlling the ratio of the fuel injection amounts from the fuel injection valves 12 and 13 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine
This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, the ECU 20 first reads the valve opening timing of the intake valve 9 in the current operating state of the internal combustion engine 1 in S401.

  Next, the ECU 20 proceeds to S402, and determines whether or not the opening timing of the intake valve 9 is retarded from the intake stroke top dead center. If an affirmative determination is made in S402, the ECU 20 proceeds to S403, and if a negative determination is made, the ECU 20 proceeds to S404.

  In S403, the ECU 20 lowers the in-port fuel injection rate and increases the in-cylinder fuel injection rate as compared with the case where the opening timing of the intake valve 9 is before the intake stroke top dead center. Thereafter, the ECU 20 proceeds to S405.

  On the other hand, in S304, the ECU 20 increases the in-port fuel injection rate and lowers the in-cylinder fuel injection rate as compared with the case where the opening timing of the intake valve 9 is retarded from the intake stroke top dead center. Thereafter, the ECU 20 proceeds to S405.

  In S405, the ECU 20 executes fuel injection from each of the fuel injection valves 12 and 13, and temporarily ends the execution of this routine.

  Also by the routine described above, the fuel injection amount from the in-port injection valve 12 is decreased and the fuel injection amount from the in-cylinder injection valve 13 is increased as the intake air inflow speed increases. Further, as the intake air inflow speed becomes slower, the fuel injection amount from the in-port injection valve 12 is increased, and the fuel injection amount from the in-cylinder injection valve 13 is decreased.

  As a result, the amount of fuel injected from the in-port injection valve 12 and adhering to the flow of intake air when flowing into the cylinder 2 and adhering to the bore wall surface can be suppressed. Moreover, it can suppress that a combustion state deteriorates because the fuel injected from the cylinder injection valve 13 is not fully mixed with intake air.

  Therefore, according to the present embodiment, it is possible to suppress deterioration of exhaust characteristics and fuel consumption. That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

  Similarly to the modification of the first embodiment described above, when the temperature in the intake port 5 is equal to or lower than the specified port internal temperature T1, or when the temperature in the cylinder 2 is equal to or lower than the specified in-cylinder temperature T2, FIG. A control routine may be executed. In such a case, it is possible to suppress deterioration of exhaust characteristics and fuel consumption during cold.

  Next, a fourth embodiment of the control system for an internal combustion engine according to the present invention will be described. In addition, since the schematic structure of the internal combustion engine and its intake / exhaust system according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted.

<Intake valve lift and valve timing control>
In the present embodiment, the lift amount and / or valve timing of the intake valve 9 is changed to change the intake air inflow speed in accordance with the in-port fuel injection rate and the in-cylinder fuel injection rate.

Specifically, as shown in FIG. 2A or 2B, the lift amount of the intake valve 9 is increased as the in-port fuel injection rate becomes higher and the in-cylinder fuel injection rate becomes lower. Further, when the opening timing of the intake valve 9 is after the top dead center of the intake stroke, the retard amount of the opening timing of the intake valve 9 decreases as the in-port fuel injection rate increases and the in-cylinder fuel injection rate decreases. To do.

  By controlling the lift amount and / or the valve opening timing of the intake valve 9 in this manner, the fuel injection amount from the in-port injection valve 12 increases and the fuel injection amount from the in-cylinder injection valve 13 decreases. The intake air inflow speed is slowed down. Further, as the fuel injection amount from the in-port injection valve 12 decreases and the fuel injection amount from the in-cylinder injection valve 11 increases, the intake inflow speed is increased.

  As a result, the amount of fuel injected from the in-port injection valve 12 and adhering to the flow of intake air when flowing into the cylinder 2 and adhering to the bore wall surface can be suppressed. Moreover, it can suppress that a combustion state deteriorates because the fuel injected from the cylinder injection valve 13 is not fully mixed with intake air.

  Further, when the lift amount and / or the valve opening timing of the intake valve 9 is changed as described above, the intake amount flowing into the cylinder 2 (hereinafter simply referred to as intake amount) may change. Specifically, when the lift amount of the intake valve 9 is increased, or when the valve opening period of the intake valve 9 is lengthened by decreasing the valve opening timing retard amount of the intake valve 9, the intake amount increases. If the lift amount of the intake valve 9 is reduced, or if the valve opening period of the intake valve 9 is shortened by increasing the valve opening timing retardation amount of the intake valve 9, the intake amount may be reduced. is there.

  Therefore, in this embodiment, when the lift amount of the intake valve 9 is increased, or when the valve opening timing retard amount of the intake valve 9 is decreased, the valve closing timing of the intake valve 9 is advanced. On the other hand, when the lift amount of the intake valve 9 is reduced or when the valve opening timing retard amount of the intake valve 9 is increased, the valve closing timing of the intake valve 9 is retarded. However, when the valve closing timing of the intake valve 9 is delayed until after the intake stroke bottom dead center, the intake valve 9 is inhaled into the cylinder 2 due to the dynamic effect of intake air even after the intake stroke bottom dead center. Within the period during which

  By changing the closing timing of the intake valve 9 in this way, if there is a possibility that the intake amount may increase, the period during which the intake air flows into the cylinder 2 is shortened, and if there is a possibility that the intake amount may decrease, the cylinder The period during which intake air flows into 2 can be lengthened. As a result, even when the lift amount and / or the valve opening timing of the intake valve 9 is changed in order to change the intake air inflow speed, it is possible to suppress the change in the intake air amount.

<Intake valve lift and valve timing control flow>
Here, a control routine for controlling the lift amount and valve timing of the intake valve 9 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, the ECU 20 first reads the in-port fuel injection rate in the current operating state of the internal combustion engine 1 in S501.

  Next, the ECU 20 proceeds to S502 and reads the valve opening timing of the intake valve 9 in the current operating state of the internal combustion engine 1.

  Next, the ECU 20 proceeds to S503 and determines whether or not the opening timing of the intake valve 9 is retarded from the intake stroke top dead center. If an affirmative determination is made in S503, the ECU 20 proceeds to S504, and if a negative determination is made, the ECU 20 proceeds to S505.

In step S504, the ECU 20 substitutes the in-port fuel injection rate read in step S501 into the map to set a target lift amount of the intake valve 9 (hereinafter referred to as a target lift amount) and a target valve opening timing retardation. An amount (hereinafter referred to as a target valve opening timing retardation amount) is derived. In this map, as shown in FIG. 2A, the relationship between the in-port fuel injection rate, the valve opening timing retard amount of the intake valve 9 and the lift amount of the intake valve 9 is determined in advance by experiments or the like. Which is stored in the ECU 20.

  Next, the ECU 20 proceeds to S506 and flows into the cylinder 2 even if the lift amount and the valve opening timing retard amount of the intake valve 9 are respectively set as the target lift amount and the target valve opening timing retard amount derived in S504. The valve closing timing of the intake valve 9 (hereinafter referred to as target valve closing timing) is calculated so that the amount of intake air to be changed hardly changes.

  Here, the relationship between the lift amount of the intake valve 9, the valve opening timing retard amount, and the valve closing timing so that the amount of intake air flowing into the cylinder 2 hardly changes is determined in advance by experiments and stored in the ECU 20 as a map. The target valve closing timing of the intake valve 9 may be calculated from the map.

  Next, the ECU 20 proceeds to S507, where the lift of the intake valve 9 is lifted based on the target lift amount and target valve opening timing retard amount derived in S504 and the target valve closing timing calculated in S506. The amount, valve opening timing, and valve closing timing are changed, and then the execution of this routine is temporarily terminated.

  On the other hand, in S505, the ECU 20 derives the target lift amount of the intake valve 9 by substituting the in-port fuel injection rate read in S501 into a map different from the map in S504. This map is a map that defines the relationship between the in-port fuel injection rate and the lift amount of the intake valve 9 when the opening timing of the intake valve 9 is before the intake stroke top dead center. As in FIG. 2A, the lift amount of the intake valve 9 is increased as the in-port fuel injection rate is increased, and the lift amount of the intake valve 9 is decreased as the in-port fuel injection rate is decreased. The map is also determined in advance by experiments or the like and stored in the ECU 20.

  Next, the ECU 20 proceeds to S508, and even if the lift amount of the intake valve 9 is set as the target lift amount derived in S505, the target valve closing of the intake valve 9 so that the intake amount flowing into the cylinder 2 hardly changes. Calculate timing.

  Here, when the valve opening timing of the intake valve 9 is before the top dead center of the intake stroke, the relationship between the lift amount of the intake valve 9 and the valve closing timing is tested so that the amount of intake air flowing into the cylinder 2 hardly changes. Alternatively, the target valve closing timing of the intake valve 9 may be calculated from the map by preliminarily determining the map and storing the map in the ECU 20.

  Next, the ECU 20 proceeds to S509, and changes the lift amount and valve closing timing of the intake valve 9 based on the target lift amount of the intake valve 9 derived in S505 and the target valve closing timing calculated in S508. After that, the execution of this routine is temporarily terminated.

  In this routine, the in-cylinder fuel injection rate is read in S501, and in S504, the in-cylinder fuel injection rate, the valve opening timing retard amount and the lift amount as shown in FIG. The target lift amount and the target valve opening timing retardation amount of the intake valve 9 may be derived from a map that defines the relationship between In this case, in S505, the intake valve 9 is determined from a map that defines the relationship between the in-cylinder fuel injection rate and the lift amount of the intake valve 9 when the opening timing of the intake valve 9 is before the intake stroke top dead center. The target lift amount is derived. Also according to the map, as in FIG. 2B, the lift amount of the intake valve 9 is decreased as the in-cylinder fuel injection rate is increased, and the lift amount of the intake valve 9 is increased as the in-cylinder fuel injection rate is decreased. Is done.

According to the control described above, it is possible to more suitably control the intake air inflow speed in accordance with the fuel injection amounts from the in-port injection valve 12 and the in-cylinder injection valve 13, and as a result, the exhaust characteristics and fuel consumption are deteriorated. It becomes possible to suppress. Further, even when the lift amount and / or the valve opening timing of the intake valve 9 is changed, it is possible to suppress the change in the intake amount. That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

  7, when the temperature in the intake port 5 is equal to or lower than the specified port internal temperature T1, or when the temperature in the cylinder 2 is equal to or lower than the specified in-cylinder temperature T2. The control routine may be executed. In such a case, it is possible to suppress deterioration of exhaust characteristics and fuel consumption during cold.

  Next, a fifth embodiment of the control system for an internal combustion engine according to the present invention will be described. In addition, since the schematic structure of the internal combustion engine and its intake / exhaust system according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted.

<Intake valve lift and valve timing control flow>
Here, a control routine for controlling the lift amount and valve timing of the intake valve 9 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, the ECU 20 first reads the in-port fuel injection rate in the current operating state of the internal combustion engine 1 in S601.

  Next, the ECU 20 proceeds to S602 and determines whether or not the in-port fuel injection rate is equal to or greater than the specified in-port fuel injection rate Rp. The fuel injection rate Rp in the specified port here means that when the fuel injection rate in the port becomes equal to or higher than the fuel injection rate Rp in the specified port, the fuel injection amount from the port injection valve 12 becomes excessive, and the intake inflow speed Is not delayed, it is a value at which it can be determined that the amount of fuel injected from the in-port injection valve 12 and adhering to the bore wall surface exceeds the allowable amount. If an affirmative determination is made in S602, the ECU 20 proceeds to S603, and if a negative determination is made, the ECU 20 once ends the execution of this routine.

  In step S <b> 603, the ECU 20 reads the valve opening timing of the intake valve 9 in the current operating state of the internal combustion engine 1.

  Next, the ECU 20 proceeds to S604, and determines whether or not the opening timing of the intake valve 9 is retarded from the intake stroke top dead center. If an affirmative determination is made in S604, the ECU 20 proceeds to S605, and if a negative determination is made, the ECU 20 proceeds to S606.

  In step S605, the ECU 20 advances the valve opening timing of the intake valve 9 before the intake stroke top dead center, and lifts the intake valve 9 as compared to the case where the in-port fuel injection rate is less than the specified in-port fuel injection rate Rp. Increase the amount. Here, only the valve opening timing advance of the intake valve 9 or the increase of the lift amount of the intake valve 9 may be controlled. Thereafter, the ECU 20 proceeds to S607.

  On the other hand, in S606, the ECU 20 increases the lift amount of the intake valve 9 as compared with the case where the in-port fuel injection rate is less than the specified in-port fuel injection rate Rp. Thereafter, the ECU 20 proceeds to S607.

In S607, the ECU 20 advances the valve closing timing of the intake valve 9 more than when the in-port fuel injection rate is less than the specified in-port fuel injection rate Rp. That is, S605 or S6
In 06, the valve closing timing of the intake valve 9 is advanced than before the valve opening timing advance of the intake valve 9 and / or the control of increasing the lift amount of the intake valve 9 is performed. Thereafter, the ECU 20 once terminates execution of this routine.

  Also by the routine as described above, the intake inflow speed is slowed as the fuel injection amount from the in-port injection valve 12 increases and the fuel injection amount from the in-cylinder injection valve 13 decreases. As a result, it is possible to suppress the amount of fuel that adheres to the flow of intake air and adheres to the bore wall surface when injected from the in-port injection valve 12 and flows into the cylinder 2. Further, in order to slow down the intake air inflow speed, even if the opening timing of the intake valve 9 is advanced and / or the lift amount of the intake valve 9 is increased, the increase in the intake air amount can be suppressed. I can do it. That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

  8, when the temperature in the intake port 5 is equal to or lower than the specified port temperature T1, or when the temperature in the cylinder 2 is equal to or lower than the specified in-cylinder temperature T2. The control routine may be executed. In such a case, it is possible to suppress the amount of fuel adhering to the bore wall surface in the flow of the intake air when it is injected from the in-port injection valve 12 and flows into the cylinder 2 when it is cold.

  Next, a sixth embodiment of the control system for an internal combustion engine according to the present invention will be described. In addition, since the schematic structure of the internal combustion engine and its intake / exhaust system according to the present embodiment is the same as that of the first embodiment, the description thereof is omitted.

<Intake valve lift and valve timing control flow>
Here, a control routine for controlling the lift amount and valve timing of the intake valve 9 according to the present embodiment will be described with reference to the flowchart shown in FIG. This routine is stored in advance in the ECU and is repeated every predetermined time.

  In this routine, the ECU 20 first reads the in-cylinder fuel injection rate in the current operating state of the internal combustion engine 1 in S701.

  Next, the ECU U20 proceeds to S702, and determines whether or not the in-cylinder fuel injection rate is equal to or greater than the specified in-cylinder fuel injection rate Rs. Here, the specified in-cylinder fuel injection rate Rs means that when the in-cylinder fuel injection rate is equal to or higher than the specified in-cylinder fuel injection rate, the fuel injection amount from the in-cylinder injection valve 13 is excessively increased, and the intake air inflow speed is When the speed is not increased, the fuel injected from the in-cylinder injection valve 13 is a value that can be determined to cause deterioration of the combustion state because the fuel is not sufficiently mixed with the intake air in the cylinder 2. If an affirmative determination is made in S702, the ECU 20 proceeds to S703, and if a negative determination is made, the ECU 20 once ends the execution of this routine.

  In step S <b> 703, the ECU 20 reads the opening timing of the intake valve 9 in the current operating state of the internal combustion engine 1.

  Next, the ECU 20 proceeds to S704 and determines whether or not the opening timing of the intake valve 9 is before the intake stroke top dead center. If an affirmative determination is made in S704, the ECU 20 proceeds to S705, and if a negative determination is made, the ECU 20 proceeds to S706.

In S705, the ECU 20 retards the opening timing of the intake valve 9 after the intake stroke top dead center, and the lift amount of the intake valve 9 compared to when the in-cylinder fuel injection rate is less than the specified in-cylinder fuel injection rate Rr. Make it smaller. Here, it is also possible to control only either the valve opening timing delay of the intake valve 9 or the lift amount decrease of the intake valve 9. Thereafter, the ECU 20 performs S70.
Proceed to 7.

  On the other hand, in S706, the ECU 20 reduces the lift amount of the intake valve 9 as compared with the case where the in-cylinder fuel injection rate is less than the specified in-cylinder fuel injection rate Rr. Thereafter, the ECU 20 proceeds to S707.

  In S707, the ECU 20 retards the closing timing of the intake valve 9 as compared with the case where the in-cylinder fuel injection rate is less than the specified in-cylinder fuel injection rate Rs. That is, in S705 or S706, the valve closing timing of the intake valve 9 is retarded as compared to before the valve opening timing delay of the intake valve 9 and / or the lift amount reduction control of the intake valve 9 is controlled. However, when the valve closing timing of the intake valve 9 is delayed until after the intake stroke bottom dead center, the intake valve 9 is inhaled into the cylinder 2 due to the dynamic effect of intake air even after the intake stroke bottom dead center. Within the period during which Thereafter, the ECU 20 once terminates execution of this routine.

  Also by the routine as described above, the intake inflow speed is increased as the fuel injection amount from the in-cylinder injection valve 13 increases and the fuel injection amount from the in-port injection valve 12 decreases. As a result, it is possible to suppress the deterioration of the combustion state due to the fuel injected from the in-cylinder injection valve 13 being not sufficiently mixed with the intake air. Further, even if the opening timing of the intake valve 9 is retarded and / or the lift amount of the intake valve 9 is decreased in order to increase the intake flow rate, it is possible to suppress a decrease in the intake amount. . That is, the internal combustion engine 1 according to the present embodiment can be more suitably controlled.

  Further, as in the above-described modification of the first embodiment, when the temperature in the intake port 5 is equal to or lower than the specified port internal temperature T1, or when the temperature in the cylinder 2 is equal to or lower than the specified in-cylinder temperature T2, FIG. The control routine may be executed. In such a case, it is possible to prevent the combustion state from deteriorating because the fuel injected from the in-cylinder injection valve 13 is not sufficiently mixed with the intake air when cold.

The figure which shows schematic structure of the internal combustion engine which concerns on the Example of this invention, and its intake-exhaust system. FIG. 2A shows the relationship between the in-port fuel injection rate, the valve opening timing retard amount when the valve opening timing of the intake valve is retarded from the top dead center of the intake stroke, and the lift amount of the intake valve. Graph. FIG. 2B shows the relationship between the in-cylinder fuel injection rate and the valve opening timing retard amount and the intake valve lift amount when the valve opening timing of the intake valve is retarded from the top dead center of the intake stroke. Graph. The flowchart figure which shows the control routine which controls the ratio of the fuel injection quantity from each fuel injection valve based on Example 1. FIG. The flowchart figure which shows the control routine which controls the ratio of the fuel injection quantity from each fuel injection valve based on the modification of Example 1. FIG. FIG. 9 is a flowchart showing a control routine for controlling the ratio of fuel injection amounts from the fuel injection valves according to the second embodiment. FIG. 9 is a flowchart showing a control routine for controlling the ratio of fuel injection amounts from the fuel injection valves according to the third embodiment. FIG. 9 is a flowchart showing a control routine for controlling the lift amount and valve timing of an intake valve according to a fourth embodiment. FIG. 9 is a flowchart showing a control routine for controlling the lift amount and valve timing of an intake valve according to a fifth embodiment. FIG. 9 is a flowchart showing a control routine for controlling the lift amount and valve timing of an intake valve according to a sixth embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Internal combustion engine 2 ... Cylinder 5 ... Intake port 7 ... Intake passage 9 ... Intake valve 11 ... Variable valve mechanism 12 ... In-port injection valve 13 ... In-cylinder injection valve 20. ・ ECU
21 ... Port temperature sensor 22 ... Water temperature sensor

Claims (14)

An intake passage injection valve for injecting fuel into the intake passage;
An in-cylinder injection valve that directly injects fuel into the cylinder;
A variable valve mechanism that changes the lift amount and / or valve timing of the intake valve;
The ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, which is the sum of the fuel injection amount from the intake passage injection valve and the fuel injection amount from the in-cylinder injection valve, and the in-cylinder Fuel injection amount ratio changing means for changing the ratio of the fuel injection amount from the injection valve,
The fuel injection amount ratio changing means increases the flow rate when the intake air flows into the cylinder by changing the lift amount and / or valve timing of the intake valve by the variable valve mechanism. A control system for an internal combustion engine, wherein a ratio of a fuel injection amount from the intake valve in the intake passage to a quantity is lowered and a ratio of a fuel injection quantity from the cylinder injection valve to a total fuel injection quantity is increased.   The fuel injection amount ratio changing means lowers the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount as the lift amount of the intake valve is reduced by the variable valve mechanism. 2. The control system for an internal combustion engine according to claim 1, wherein a ratio of a fuel injection amount from the in-cylinder injection valve to a fuel injection amount is increased.   When the valve opening timing of the intake valve is delayed from the intake stroke top dead center by the variable valve mechanism, the fuel injection amount ratio changing means increases the intake amount relative to the total fuel injection amount. 3. The internal combustion engine according to claim 1, wherein the ratio of the fuel injection amount from the in-passage injection valve is lowered, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is increased. Control system.   When the lift amount of the intake valve is equal to or less than a specified lift amount, the fuel injection amount ratio changing means is configured to change the inside of the intake passage relative to the total fuel injection amount, compared with a case where the lift amount of the intake valve is larger than the specified lift amount. 2. The control system for an internal combustion engine according to claim 1, wherein the ratio of the fuel injection amount from the injection valve is lowered, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is increased. When the lift amount of the intake valve is equal to or less than the specified lift amount, the specified lift amount is a value that causes the amount of fuel injected from the intake valve injection valve and attached to the bore wall surface of the cylinder to exceed the allowable amount. The control system for an internal combustion engine according to claim 4, wherein the control system is provided.   When the opening timing of the intake valve is retarded from the intake stroke top dead center by the variable valve mechanism, the fuel injection amount ratio changing means is configured so that the opening timing of the intake valve is before the intake stroke top dead center. The ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is reduced and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is increased compared to the case where the advance is advanced. 2. The control system for an internal combustion engine according to claim 1, wherein: At least one of intake passage temperature detection means for detecting the temperature in the intake passage and in-cylinder temperature detection means for detecting the temperature in the cylinder;
When the temperature in the intake passage detected by the intake passage temperature detecting means is equal to or lower than the specified intake passage temperature, or the temperature in the cylinder detected by the in-cylinder temperature detecting means is equal to or lower than the specified in-cylinder temperature. In this case, the fuel injection amount ratio changing means increases as the flow rate when the intake air flows into the cylinder increases by changing the lift amount and / or valve timing of the intake valve by the variable valve mechanism. The ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is lowered, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is increased. The control system of the internal combustion engine according to any one of 1 to 6 . An intake passage injection valve for injecting fuel into the intake passage;
An in-cylinder injection valve that directly injects fuel into the cylinder;
A variable valve mechanism that changes the lift amount and / or valve timing of the intake valve;
The ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, which is the sum of the fuel injection amount from the intake passage injection valve and the fuel injection amount from the in-cylinder injection valve, and the in-cylinder Fuel injection amount ratio changing means for changing the ratio of the fuel injection amount from the injection valve,
The fuel injection amount ratio changing means increases the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is low. The variable valve mechanism changes the lift amount and / or the valve timing of the intake valve so that the flow rate when the intake air flows into the cylinder becomes slower as the intake gas is reduced. system. The fuel injection amount ratio changing means increases the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount, and the ratio of the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount is low. 9. The control system for an internal combustion engine according to claim 8 , wherein the variable valve mechanism increases the lift amount of the intake valve as the speed is increased. When the opening timing of the intake valve is after the top dead center of the intake stroke, the fuel injection amount ratio changing means increases the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount. The internal combustion engine according to claim 8 , wherein the variable valve mechanism advances the valve opening timing of the intake valve as the ratio of the fuel injection amount from the in-cylinder injection valve to the fuel injection amount is lowered. Engine control system. When the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is equal to or greater than a specified ratio, the variable valve mechanism is configured to provide a ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount. There as compared with the case of less than the specified ratio, as the flow velocity becomes slow when the intake into the cylinder flows, according to claim 8, wherein changing the lift amount and / or valve timing of the intake valve Internal combustion engine control system. The specified ratio is the ratio of the fuel injection amount from the intake valve in the intake passage to the total fuel injection amount
The internal combustion engine according to claim 11, wherein the amount of fuel injected from the intake passage injection valve and adhering to a bore wall surface in the cylinder is greater than an allowable amount when the fuel is greater than the specified ratio. Control system. When changing the lift amount and / or valve timing of the intake valve in order to change the flow velocity when intake air flows into the cylinder, the variable valve mechanism moves into the cylinder before and after the change. 9. The control system for an internal combustion engine according to claim 8 , wherein the closing timing of the intake valve is changed so that the amount of intake air flowing in hardly changes. At least one of intake passage temperature detection means for detecting the temperature in the intake passage and in-cylinder temperature detection means for detecting the temperature in the cylinder;
When the temperature in the intake passage detected by the intake passage temperature detecting means is equal to or lower than the specified intake passage temperature, or the temperature in the cylinder detected by the in-cylinder temperature detecting means is equal to or lower than the specified in-cylinder temperature. In this case, the ratio of the fuel injection amount from the intake passage injection valve to the total fuel injection amount is increased by the fuel injection amount ratio changing means, and the fuel injection amount from the in-cylinder injection valve to the total fuel injection amount The variable valve mechanism changes the lift amount and / or the valve timing of the intake valve so that the flow rate when the intake air flows into the cylinder becomes slower as the ratio of is reduced. The control system for an internal combustion engine according to any one of claims 8 to 13 .

Images