JP6911815B2 - Internal combustion engine control device - Google Patents

Description

The present invention relates to an internal combustion engine control device applied to an internal combustion engine including a port injection valve for injecting fuel into an intake passage.

For example, Patent Document 1 below describes a control device that executes a multi-injection process in which fuel injected into one cylinder in one combustion cycle is divided into an exhaust stroke and an intake stroke and injected. This control device sets the injection timing in the intake stroke to a predetermined timing (“0017”, “0024”).

Japanese Unexamined Patent Publication No. 2005-291133

The inventor has found that the number of particulate matter (PM) (PN) in the exhaust varies greatly depending on the injection timing in the intake stroke. Therefore, fixing the injection timing has a problem in controlling the exhaust component well.

Hereinafter, means for solving the above problems and their actions and effects will be described.

1. 1. It is applied to an internal combustion engine provided with a port injection valve that injects fuel into the intake passage, and the port injection valve is operated to inject fuel in a required injection amount, which is the injection amount required in one combustion cycle. A multi-injection process that executes an intake synchronous injection that injects fuel in synchronization with the valve opening period, an intake asynchronous injection that injects fuel at a timing on the advance side of the intake synchronous injection, and the internal combustion engine. The injection timing of the intake synchronous injection expressed by the rotation angle of the crank shaft of the internal combustion engine is three of the rotation speed of the crank shaft of the internal combustion engine, the opening start timing of the intake valve, and the temperature of the intake system of the internal combustion engine. It is a control device for an internal combustion engine that executes variable processing that is variably set based on at least two of the parameters.

When the temperature of the intake system of the internal combustion engine is low and all the fuel of the required injection amount is injected by intake asynchronous injection, the number of particulate matter (PM) (PN) in the exhaust may increase depending on the load. .. It is presumed that this is because the amount of fuel adhering to the intake system increases, and due to the shearing of the adhering fuel, PM is generated when a part of the fuel flows into the combustion chamber as droplets. Therefore, in the above configuration, a part of the required injection amount is injected by the intake synchronous injection to reduce the asynchronous injection amount and, by extension, the amount of fuel adhering to the intake system. As a result, it is possible to prevent the fuel from flowing into the combustion chamber as droplets due to the shearing of the attached fuel.

However, the inventor has found that the injection timing of the intake synchronous injection for reducing the PN as much as possible changes depending on the rotation speed of the crankshaft. This is because the flow velocity in the intake passage changes depending on the rotation speed, so the amount of fuel that stays attached to the intake system without flowing into the combustion chamber tends to change, and the fuel was injected from the port injection valve. It is presumed that the reason is that the amount of rotation of the crankshaft changes within the period until a predetermined amount of fuel is vaporized. On the other hand, in the above configuration, if the injection timing of the intake synchronous injection is variably set according to the rotation speed, the PN can be suppressed as compared with the case where the injection timing is not variable according to the rotation speed.

Further, the inventor has found that the injection timing of the intake synchronous injection for reducing the PN as much as possible changes depending on the valve opening start timing of the intake valve. This is because the amount of internal EGR changes as the amount of overlap between the intake valve and the exhaust valve changes according to the valve opening start time, so the temperature of the intake system rises and fuel vaporizes in the intake system. It is presumed that the factors are the change in ease and the change in the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber. On the other hand, in the above configuration, if the injection timing of the intake synchronous injection is variably set according to the valve opening start timing, the PN can be suppressed as compared with the case where the injection timing is not changed according to the valve opening start timing.

Further, the inventor has found that the injection timing of the intake synchronous injection for reducing the PN as much as possible changes depending on the temperature of the intake system. It is presumed that this is because the ease of vaporization of fuel in the intake system differs depending on the temperature of the intake system. On the other hand, in the above configuration, if the injection timing of the intake synchronous injection is variably set according to the temperature of the intake system, PN can be suppressed as compared with the case where the injection timing is not changed according to the temperature of the intake system.

2. Based on the amount of fresh air filled in the cylinder of the internal combustion engine, a required injection amount calculation process for calculating the required injection amount as an injection amount for controlling the air-fuel ratio to the target air-fuel ratio is executed, and the variable process is performed. The internal combustion engine control device according to 1 above, which is a process of variably setting the injection timing of the intake synchronous injection based on the load of the internal combustion engine in addition to the at least two parameters.

The inventor has found that the injection timing for reducing PN as much as possible changes depending on the load of the internal combustion engine. It is presumed that this is because the amount of fuel injected changes depending on the load, and the ease of atomization of the fuel changes due to the change in the pressure in the intake passage. Therefore, in the above configuration, the injection timing of the intake synchronous injection is variably set according to the load. As a result, PN can be suppressed as compared with the case where it is not variable according to the load.

3. 3. The variable processing is based on the rotation speed, the temperature of the intake system, and the load, and is a target value of the timing at which the fuel injected from the port injection valve reaches the inlet of the combustion chamber of the internal combustion engine at the latest timing. The control device for an internal combustion engine according to the above 2, which includes an end time setting process for variably setting a certain arrival end time and a start time calculation process for calculating the injection start time of the intake synchronous injection based on the arrival end time. be.

According to the inventor, the PN fluctuates greatly due to the fluctuation of the timing at which the fuel injected at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine, and even if the injection ratio between the intake synchronous injection and the intake asynchronous injection is slightly changed. , It was found that the optimum timing for suppressing PN hardly changes. Therefore, in the above configuration, by setting the injection start time after setting the arrival end time, it is possible to manage an appropriate time for suppressing PN by the arrival end time, which is a parameter handled by the control device. can.

4. The internal combustion engine includes a valve characteristic variable device that changes the valve characteristics of the intake valve, and executes a valve characteristic control process that variably controls the valve opening start timing of the intake valve by operating the valve characteristic variable device. The end time setting process includes a retard angle calculation process for calculating the retard angle amount of the arrival end time with respect to the valve opening start time based on the rotation speed, the temperature of the intake system, and the load. The control device for an internal combustion engine according to the above 3, which is a process in which a timing retarded by the amount of the retard angle with respect to the valve start timing is set as the arrival end timing.

The inventor has found that the injection timing of the intake synchronous injection for reducing the PN as much as possible changes depending on the valve opening start timing of the intake valve. This is because the amount of internal EGR changes as the amount of overlap between the intake valve and the exhaust valve changes according to the valve opening start time, so the temperature of the intake system rises and fuel vaporizes in the intake system. It is presumed that the factors are the change in ease and the change in the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber. Therefore, in the above configuration, the injection timing of the intake synchronous injection is variably set according to the valve opening start timing. As a result, PN can be suppressed as compared with the case where the valve opening start time is not changed.

In particular, in the above configuration, instead of directly calculating the arrival end time, the retard angle amount with respect to the valve opening start time is calculated first, so that the valve opening start time is not used as the parameter used for calculating the retard angle amount. The arrival end time can be variably set according to the valve opening start time.

5. It is applied to an internal combustion engine provided with a port injection valve that injects fuel into the intake passage, and the port injection valve is operated to inject fuel in a required injection amount, which is the injection amount required in one combustion cycle. A multi-injection process that executes an intake synchronous injection that injects fuel in synchronization with the valve opening period, an intake asynchronous injection that injects fuel at a timing on the advance side of the intake synchronous injection, and the internal combustion engine. A variable process for variably setting the injection timing of the intake synchronous injection expressed by the rotation angle of the crank shaft is executed, and the variable process is the slowest from the port injection valve based on the rotation speed of the crank shaft. The injection of the intake synchronous injection is based on the end time setting process for variably setting the arrival end time, which is the target value of the timing at which the fuel injected at the timing reaches the inlet of the combustion chamber of the internal combustion engine, and the arrival end time. It is a control device for an internal combustion engine including a start time calculation process for calculating a start time.

When the temperature of the intake system of the internal combustion engine is low and all the fuel of the required injection amount is injected by intake asynchronous injection, the number of particulate matter (PM) (PN) in the exhaust may increase depending on the load. .. It is presumed that this is because the amount of fuel adhering to the intake system increases, and due to the shearing of the adhering fuel, PM is generated when a part of the fuel flows into the combustion chamber as droplets. Therefore, in the above configuration, a part of the required injection amount is injected by synchronous injection to reduce the asynchronous injection amount and, by extension, the amount of fuel adhering to the intake system. As a result, it is possible to prevent the fuel from flowing into the combustion chamber as droplets due to the shearing of the attached fuel.

However, the PN fluctuates greatly due to the fluctuation of the timing when the fuel injected at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine, and even if the injection ratio between the intake synchronous injection and the intake asynchronous injection is slightly changed, the PN The inventor has found that the optimum timing does not change much in suppressing the above. Therefore, in the above configuration, by setting the injection start time after setting the arrival end time, it is possible to manage an appropriate time for suppressing PN by the arrival end time, which is a parameter handled by the control device. can.

By the way, the inventor has found that the arrival end time for reducing PN as much as possible changes depending on the rotation speed of the crankshaft. This is because the flow velocity in the intake passage changes depending on the rotation speed, so the amount of fuel that stays attached to the intake system without flowing into the combustion chamber tends to change, and the fuel was injected from the port injection valve. It is presumed that the reason is that the amount of rotation of the crankshaft changes within the period until a predetermined amount of fuel is vaporized. Therefore, in the above configuration, by setting the arrival end time variably according to the rotation speed, PN can be suppressed as compared with the case where the arrival end time is not variably set according to the rotation speed.

6. The end time setting process is the internal combustion engine control device according to the above 5, which includes a process of variably setting the arrival end time based on the load of the internal combustion engine in addition to the rotation speed.

The inventor has found that the arrival end time for reducing PN as much as possible changes depending on the load of the internal combustion engine. It is presumed that this is because the amount of fuel injected changes depending on the load, and the ease of atomization of the fuel changes due to the change in the pressure in the intake passage. Therefore, in the above configuration, the arrival end time is variably set according to the load. As a result, PN can be suppressed as compared with the case where it is not variable according to the load.

7. The internal combustion engine includes a valve characteristic variable device that changes the valve characteristics of the intake valve, and executes a valve characteristic control process that variably controls the valve opening start timing of the intake valve by operating the valve characteristic variable device. The end time setting process includes a retard angle amount calculation process for calculating the retard angle amount of the arrival end time with respect to the valve opening start time based on the rotation speed and the load, and the valve opening start time. The control device for an internal combustion engine according to the above 6, which is a process in which a timing retarded by the amount of the retard angle is set as the arrival end time.

The inventor has found that the arrival end time for reducing PN as much as possible changes depending on the valve opening start time of the intake valve. This is because the amount of internal EGR changes as the amount of overlap between the intake valve and the exhaust valve changes according to the valve opening start time, so the temperature of the intake system rises and fuel vaporizes in the intake system. It is presumed that the factors are the change in ease and the change in the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber. Therefore, in the above configuration, the arrival end time is variably set according to the valve opening start time. As a result, PN can be suppressed as compared with the case where the valve opening start time is not changed.

In particular, in the above configuration, instead of directly calculating the arrival end time, the retard angle amount with respect to the valve opening start time is calculated first, so that the valve opening start time is not used as the parameter used for calculating the retard angle amount. The arrival end time can be variably set according to the valve opening start time.

The figure which shows the control device and the internal combustion engine which concerns on 1st Embodiment. The block diagram which shows the process executed by the control device which concerns on the same embodiment. (A) and (b) are diagrams showing the injection pattern according to the same embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on the same embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on the same embodiment. (A) and (b) are diagrams showing the fluctuation of the PN discharge amount depending on the valve opening timing of the intake valve. The flow chart which shows the procedure of the injection valve operation processing which concerns on 2nd Embodiment. The flow chart which shows the procedure of the injection valve operation processing which concerns on 3rd Embodiment.

<First Embodiment>
Hereinafter, an embodiment of a control device for an internal combustion engine will be described with reference to the drawings.

The internal combustion engine 10 shown in FIG. 1 is mounted on a vehicle. A throttle valve 14 and a port injection valve 16 are provided in the intake passage 12 of the internal combustion engine 10 in this order from the upstream side. The air sucked into the intake passage 12 and the fuel injected from the port injection valve 16 flow into the combustion chamber 24 partitioned by the cylinder 20 and the piston 22 as the intake valve 18 opens. In the combustion chamber 24, the air-fuel mixture is subjected to combustion by the spark discharge of the ignition device 26. Then, the combustion energy generated by the combustion is converted into the rotational energy of the crankshaft 28 via the piston 22. The air-fuel mixture used for combustion is discharged to the exhaust passage 32 as exhaust gas when the exhaust valve 30 is opened. A catalyst 34 is provided in the exhaust passage 32.

The rotational power of the crankshaft 28 is transmitted to the intake side camshaft 40 and the exhaust side camshaft 42 via the timing chain 38. In the present embodiment, the power of the timing chain 38 is transmitted to the intake side camshaft 40 via the intake side valve timing adjusting device 44. The intake side valve timing adjusting device 44 is an actuator that adjusts the valve opening timing of the intake valve 18 by adjusting the rotational phase difference between the crankshaft 28 and the intake side cam shaft 40.

The control device 50 controls the internal combustion engine 10, and in order to control the control amount (torque, exhaust component ratio, etc.), the throttle valve 14, the port injection valve 16, the ignition device 26, and the intake side valve timing adjustment. The operation unit of the internal combustion engine 10 such as the device 44 is operated. At this time, the control device 50 uses the output signal Scr of the crank angle sensor 60, the intake air amount Ga detected by the air flow meter 62, the air-fuel ratio Af detected by the air-fuel ratio sensor 64, and the output of the intake side cam angle sensor 66. The signal Sca and the temperature (water temperature THW) of the cooling water of the internal combustion engine 10 detected by the water temperature sensor 68 are referred to. Further, the control device 50 refers to the terminal voltage Vb of the battery 70 detected by the voltage sensor 72. Here, the battery 70 serves as a power source for the port injection valve 16 and the like. Note that FIG. 1 shows operation signals MS1 to MS5 for operating each of the throttle valve 14, the port injection valve 16, the ignition device 26, the starter motor 36, and the intake side valve timing adjusting device 44.

The control device 50 includes a CPU 52, a ROM 54, and a power supply circuit 56 that supplies electric power to each location in the control device 50. The CPU 52 executes a program stored in the ROM 54 to control the control amount. Execute.

FIG. 2 shows a part of the processing executed by the control device 50. The process shown in FIG. 2 is realized by the CPU 52 executing the program stored in the ROM 54.

The intake phase difference calculation process M10 is based on the output signal Scr of the crank angle sensor 60 and the output signal Sca of the intake side cam angle sensor 66, and is the phase difference of the rotation angle of the intake side cam shaft 40 with respect to the rotation angle of the crankshaft 28. This is a process for calculating a certain intake phase difference DIN. The target intake phase difference calculation process M12 is a process for variably setting the target intake phase difference DIN * based on the operating point of the internal combustion engine 10. In this embodiment, the operating point is defined by the rotation speed NE and the filling efficiency η. Here, the CPU 52 calculates the rotation speed NE based on the output signal Scr of the crank angle sensor 60, and calculates the filling efficiency η based on the rotation speed NE and the intake air amount Ga. The filling efficiency η is a parameter that determines the amount of fresh air filled in the combustion chamber 24.

The intake phase difference control process M14 outputs an operation signal MS5 to the intake side valve timing adjustment device 44 in order to operate the intake side valve timing adjustment device 44 in order to control the intake phase difference DIN to the target intake phase difference DIN *. It is a process.

The base injection amount calculation process M20 is a process of calculating the base injection amount Qb, which is the base value of the fuel amount for setting the air-fuel ratio of the air-fuel mixture in the combustion chamber 24 as the target air-fuel ratio, based on the filling efficiency η. Specifically, in the base injection amount calculation process M20, for example, when the filling efficiency η is expressed as a percentage, the filling efficiency η is set to the fuel amount QTH per 1% of the filling efficiency η for setting the air-fuel ratio as the target air-fuel ratio. The process may be such that the base injection amount Qb is calculated by multiplying. The base injection amount Qb is a fuel amount calculated to control the air-fuel ratio to the target air-fuel ratio based on the amount of fresh air filled in the combustion chamber 24. Incidentally, the target air-fuel ratio may be, for example, the theoretical air-fuel ratio.

The feedback processing M22 calculates a feedback correction coefficient KAF obtained by adding "1" to the correction ratio δ of the base injection amount Qb as the feedback operation amount, which is the operation amount for feedback-controlling the air-fuel ratio Af to the target value Af *. It is a process to output. Specifically, the feedback processing M22 holds and outputs the output values of the proportional element and the differential element that input the difference between the air-fuel ratio Af and the target value Af *, and the integrated value of the values corresponding to the difference. Let the sum of the output values of be the correction ratio δ.

The low temperature correction process M24 is a process of calculating the low temperature increase coefficient Kw to a value larger than “1” in order to increase the base injection amount Qb when the water temperature THW is less than the predetermined temperature Tth (for example, 60 ° C.). Specifically, the low temperature increase coefficient Kw is calculated to be a larger value when the water temperature THW is low than when it is high. When the water temperature THW is equal to or higher than the predetermined temperature Tth, the low temperature increase coefficient Kw is set to "1", and the correction amount of the base injection amount Qb by the low temperature increase coefficient Kw is set to zero.

The injection valve operation process M30 is a process of outputting an operation signal MS2 to the port injection valve 16 in order to operate the port injection valve 16. In particular, the injection valve operation process M30 performs port injection based on the base injection amount Qb, the feedback correction coefficient KAF, and the low temperature increase coefficient Kw when the accuracy of the intake air amount Ga detected by the air flow meter 62 is within the allowable range. This is a process of outputting the operation signal MS2 to the valve 16. More specifically, it is a process of injecting the required injection amount Qd, which is the amount of fuel required to be supplied from the port injection valve 16 to one cylinder within one combustion cycle, from the port injection valve 16. Here, the required injection amount Qd is "KAF · Kw · Qb".

In the present embodiment, the fuel injection process includes two types of processes, a process illustrated in FIG. 3 (a) and a process illustrated in FIG. 3 (b).

FIG. 3A shows two types of intake synchronous injection, in which fuel is injected in synchronization with the valve opening period of the intake valve 18, and intake asynchronous injection, in which fuel is injected at a timing on the advance side of the intake synchronous injection. It is a multi-injection process that executes fuel injection. Specifically, in the intake synchronous injection, the fuel is injected so that the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 falls within the valve opening period of the intake valve 18. .. Here, the position before valve opening is the downstream end of the intake port, in other words, the inlet IN portion to the combustion chamber 24 shown in FIG. Note that FIG. 1 shows a state in which the intake valve 18 is open. Further, the start point of the "reaching period" is the timing at which the fuel injected from the port injection valve 16 reaches the position before the valve is opened at the earliest timing, and the end point is the port injection valve. This is the timing at which the fuel injected at the latest timing among the fuels injected from 16 reaches the position before valve opening. On the other hand, in the intake asynchronous injection, the fuel injected from the port injection valve 16 is injected so as to reach the intake valve 18 before the intake valve 18 is opened. In other words, the intake asynchronous injection is an injection in which the fuel injected from the port injection valve 16 stays in the intake passage 12 until the intake valve 18 is opened, and then flows into the combustion chamber 24 after the valve is opened. be. In the intake asynchronous injection in the present embodiment, the fuel is injected so that the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 falls within the valve closing period of the intake valve 18. It shall be.

FIG. 3B is a single injection process that executes only intake asynchronous injection.

In the present embodiment, the multi-injection process is performed with the aim of reducing the number of particulate matter (PM) (PN) in the exhaust. That is, when the temperature of the intake system of the internal combustion engine 10 such as the intake passage 12 and the intake valve 18 is low to some extent, the PN tends to increase when the single injection process is executed in the region where the filling efficiency η is large to some extent. It is considered that this is because when the filling efficiency η is large, the required injection amount Qd becomes a value larger than when it is small, and as a result, the amount of fuel adhering to the intake system increases. Specifically, when the amount of fuel adhering to the intake system increases to some extent, it is presumed that this is because a part of the adhering fuel flows into the combustion chamber 24 as droplets due to the shearing of the adhering fuel. Therefore, in the present embodiment, the required injection amount Qd
By injecting a part of the fuel by the intake synchronous injection, even if the required injection amount Qd is large, the amount of fuel adhering to the intake system is reduced for the large required injection amount Qd, and eventually the PN is reduced. .. At the time of cold start of the internal combustion engine 10, since the injection amount increases regardless of the filling efficiency η, the PN tends to increase when the single injection process is executed.

FIG. 4 shows a processing procedure of the injection valve operation processing M30. The process shown in FIG. 4 is realized by the CPU 52 repeatedly executing the program stored in the ROM 54, for example, at a predetermined cycle. In the following, the step number of each process is represented by a number prefixed with "S".

In the series of processes shown in FIG. 4, the CPU 52 first determines whether or not it is within a predetermined period after the starter motor 36 is started (described as "after the starter is turned on" in the figure) (S10). Here, the predetermined period is a period during which the amount of air filled in the combustion chamber 24 cannot be accurately grasped and the base injection amount Qb cannot be calculated accurately. When the CPU 52 determines that the period is within the predetermined period (S10: YES), the CPU 52 determines whether or not there is a request for the multi-injection process (S12). Here, the CPU 52 determines that there is a request for the multi-injection process when the water temperature THW is less than the predetermined temperature Tth. When the CPU 52 determines that there is a request for multi-injection processing (S12: YES), it is the water temperature THW, the number of injections after the starter is turned on, and the elapsed time from the previous stop of the internal combustion engine 10 to the current start. Based on the stop time Tstp of the internal combustion engine 10, the asynchronous injection amount Qns, which is the injection amount of the intake asynchronous injection, is calculated (S14). Here, the CPU 52 calculates the asynchronous injection amount Qns to a larger value when the water temperature THW is low than when it is high. Further, the CPU 52 calculates the asynchronous injection amount Qns to a larger value when the stop time Tstp is long than when it is short.

Next, the CPU 52 calculates the synchronous injection amount Qs, which is the injection amount of the intake synchronous injection, based on the water temperature THW (S16). Here, the CPU 52 calculates the synchronous injection amount Qs to a larger value when the water temperature THW is low than when it is high.

The sum of the asynchronous injection amount Qns and the synchronous injection amount Qs is the required injection amount Qd, which is the injection amount required for one combustion cycle. That is, the processing of S14 and S16 can be regarded as the processing of dividing the fuel having the required injection amount Qd into the asynchronous injection amount Qns and the synchronous injection amount Qs.

Next, the CPU 52 calculates the injection start time Is (crank angle) of the intake synchronous injection based on the water temperature THW, the rotation speed NE, and the intake phase difference DIN (S18). Here, the water temperature THW is a parameter having a positive correlation with the intake system of the internal combustion engine 10, and if the water temperature THW is different, the ease of vaporization of the fuel adhering to the intake system tends to be different. The appropriate injection start time Is is dependent on the water temperature THW. Further, if the rotation speed NE is different, the flow velocity of the fluid in the intake passage 12 is different, so that the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber 24 is different. Further, if the rotation speed NE is different, the rotation amount of the crankshaft 28 will be different within the period until a predetermined amount of fuel is vaporized among the fuels injected from the port injection valve 16. Therefore, the injection start time Is, which is appropriate for suppressing PN, depends on the rotation speed NE. Further, when the intake phase difference DIN is different, the overlap amount in which the valve opening period of the intake valve 18 and the valve opening period of the exhaust valve 30 overlap is different, and the amount of fluid blown back from the combustion chamber 24 to the intake passage 12 is increased. It will be different. If the amount of blowback is different, the temperature of the intake system is different, so that the ease of vaporization of the fuel in the intake system is different, and the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber 24 is increased. different. Therefore, the appropriate injection start time Is for suppressing PN depends on the intake phase difference DIN. Since the target intake phase difference DIN * cannot be made variable based on the filling efficiency η within a predetermined period after the starter is turned on, the target intake phase difference DIN * may be set as a fixed value. Even in this case, since the fixed position may differ for each vehicle, the versatility of the processing of S18 can be enhanced by calculating the injection start time Is based on the intake phase difference DIN.

Specifically, the CPU 52 maps the injection start time Is with the map data having the water temperature THW, the rotation speed NE, and the intake phase difference DIN as the input variables and the injection start time Is as the output variable stored in the ROM 54 in advance. It is a process to calculate. Here, the map data is a set of data of discrete values of input variables and values of output variables corresponding to the values of the input variables. In the map calculation, for example, when the value of the input variable matches any of the values of the input variable of the map data, the value of the output variable of the corresponding map data is used as the calculation result, whereas when they do not match, the map is used. The process may be such that the value obtained by interpolating the values of a plurality of output variables included in the data is used as the calculation result.

Next, the CPU 52 calculates the injection start timing Ins (crank angle) of the intake asynchronous injection (S20). Here, the CPU 52 calculates the injection start time Ins of the intake asynchronous injection so that the time interval between the injection end time of the intake asynchronous injection and the injection start time Is of the intake synchronous injection is equal to or longer than a predetermined time. Here, the predetermined time is determined by the structure of the port injection valve 16 in order to prevent the retard side injection from starting before the end of the advance side injection among the fuel injections adjacent to each other in chronological order. It's time. Then, the CPU 52 outputs an operation signal MS2 to the port injection valve 16 to inject fuel having an asynchronous injection amount Qns at the injection start time Ins to operate the port injection valve 16, and then operates the port injection valve 16 at the injection start time Is. The operation signal MS2 is output to the port injection valve 16 to inject the fuel of the above, and the port injection valve 16 is operated (S22).

On the other hand, when the CPU 52 determines that there is no execution request for the multi-injection process (S12: NO), the injection required for one combustion cycle is based on the water temperature THW, the number of injections after the starter is turned on, and the stop time Tstp. The required injection amount Qd, which is an amount, is calculated (S24). Next, the CPU 52 sets the injection start time Isin (crank angle) (S26). Then, the CPU 52 outputs the operation signal MS2 to the port injection valve 16 to inject the fuel of the required injection amount Qd at the injection start time Isin, and operates the port injection valve 16 (S22).

The CPU 52 temporarily ends the series of processes shown in FIG. 4 when the process of S22 is completed or when a negative determination is made in the process of S10.

FIG. 5 shows a processing procedure of the injection valve operation processing M30. The process shown in FIG. 5 is realized by the CPU 52 repeatedly executing the program stored in the ROM 54, for example, at a predetermined cycle.

In the series of processes shown in FIG. 5, the CPU 52 first determines whether or not a predetermined period has elapsed since the starter motor 36 was turned on (S30). Then, when it is determined that the predetermined period has elapsed (S30: YES), the CPU 52 determines whether or not there is a multi-injection request (S32). Here, the CPU 52 has a condition (a) that the water temperature THW is equal to or lower than the predetermined temperature Tth, a condition (b) that the filling efficiency η is equal to or higher than the specified value, and a condition that the rotation speed NE is equal to or lower than the predetermined speed NEth. It is determined that there is a request to execute the multi-injection process when the logical product with the condition (c) of is true. The condition (c) is a condition for ensuring a time interval between the end timing of the intake asynchronous injection and the start timing of the intake synchronous injection. Further, this condition is a condition for suppressing an excessive amount of heat generation due to an increase in the calculation load of the control device 50 because the calculation load of the multi-injection process is larger than that of the single injection process.

Then, when it is determined that there is a multi-injection request (S32: YES), the CPU 52 calculates the synchronous injection amount Qs, which is the injection amount of the intake synchronous injection (S34). Here, the CPU 52 has a synchronous injection amount Q according to the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN.
Calculate s. Specifically, the CPU 52 stores the synchronous injection amount Qs in advance in the ROM 54 with the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN as the input variables and the synchronous injection amount Qs as the output variable. Is calculated on the map.

Next, the CPU 52 calculates the asynchronous injection amount Qns, which is the injection amount of the intake asynchronous injection, by subtracting the synchronous injection amount Qs from the required injection amount Qd “Qb, KAF, Kw” (S36).

Therefore, the sum of the asynchronous injection amount Qns and the synchronous injection amount Qs is equal to the required injection amount Qd. That is, by the processing of S34 to S36, the fuel having the required injection amount Qd is divided into the asynchronous injection amount Qns and the synchronous injection amount Qs. Incidentally, the synchronous injection amount Qs is not affected by the values of the feedback correction coefficient KAF and the low temperature increase coefficient Kw. In this way, the reason for fixing the synchronous injection amount Qs is that the change in the exhaust component ratio when the synchronous injection amount Qs is changed is more remarkable than the change in the exhaust component ratio when the asynchronous injection amount Qns is changed. Is.

Next, the CPU 52 determines the timing at which the fuel injected from the port injection valve 16 reaches the position in the valve closing period of the intake valve 18 at the latest timing based on the rotation speed NE and the filling efficiency η. The arrival end time AEs shown in FIG. 3A, which is the target value, is calculated (S38). Here, if the rotation speed NE is different, the flow velocity of the fluid in the intake passage 12 is changed, so that the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber 24 is different. Further, if the rotation speed NE is different, the rotation amount of the crankshaft 28 within the period required for vaporizing a predetermined amount of the fuel injected from the port injection valve 16 will be different. Therefore, the appropriate arrival end time AEs for suppressing PN depends on the rotation speed NE. Further, if the filling efficiency η is different, the base injection amount Qb is different, and thus the amount of fuel adhering to the intake system is different. Further, if the filling efficiency η is different, the pressure in the intake passage 12 changes, and the ease of atomization of the fuel becomes different. Therefore, the appropriate arrival end time AEs for suppressing PN depends on the filling efficiency η.

Next, the CPU 52 substitutes the value obtained by multiplying the arrival end time AEs calculated by the processing of S38 by the water temperature correction coefficient Kthw, which is a correction coefficient according to the water temperature THW, into the arrival end time AEs (S40).

Here, the arrival end time AEs is a value that is larger as the value on the advance side with respect to the reference crank angle located on the retard side than the position on the most retard side that is assumed. The water temperature correction coefficient Kthw is a value larger than zero. Specifically, the CPU 52 corrects the arrival end time AEs to the retard side by calculating the water temperature correction coefficient Kthw to a smaller value than when the water temperature THW is high. This is because when the water temperature THW is low, the fuel is less likely to vaporize in the intake system than when the water temperature is high, and the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber 24 increases. This is in consideration of the fact that the optimum time for suppressing the fuel is shifted to the retard side.

Then, the CPU 52 calculates the injection start time Is of the intake synchronous injection based on the arrival end time AEs, the synchronous injection amount Qs, the rotation speed NE, and the terminal voltage Vb obtained by the process of S40 (S42). Here, the CPU 52 calculates the injection start time Is to a value on the advance angle side when the synchronous injection amount Qs is large, as compared with the case where the synchronous injection amount Qs is small. Further, the CPU 52 sets the injection start time Is to a value on the advance angle side when the rotation speed NE is large and when it is small. Specifically, the CPU 52 sets the timing advanced with respect to the arrival end time AEs by the value obtained by adding the injection period by the port injection valve 16 determined from the synchronous injection amount Qs, the flight time, and the invalid injection time as the injection start time Is. .. Here, the flight time is the time required for the fuel injected from the port injection valve 16 to reach the inlet IN of the combustion chamber 24, and is set to a fixed value in the present embodiment. The invalid injection time is the time from when the operation signal MS2 for opening the port injection valve 16 is output until the fuel injection is actually started. Since the invalid injection time depends on the drive voltage applied to the port injection valve 16, the CPU 52 calculates the invalid injection time according to the terminal voltage Vb in the present embodiment.

Next, the CPU 52 calculates the injection start time Ins of asynchronous injection based on the injection start time Is (S44). Here, the time interval between the injection end time and the injection start time Is of the intake asynchronous injection is set to be equal to or longer than the above-mentioned predetermined time.

By the above process, the injection start time Is of the intake synchronous injection is set independently of the injection start time Ins of the intake asynchronous injection. This is because the above-mentioned arrival end time AEs of the intake synchronous injection is particularly likely to affect the PN and HC in the exhaust.

Then, the CPU 52 injects fuel having an asynchronous injection amount Qns at the injection start time Ins, and then outputs an operation signal MS2 to the port injection valve 16 in order to inject fuel having a synchronous injection amount Qs at the injection start time Is. The port injection valve 16 is operated (S46).

On the other hand, when the CPU 52 determines that there is no request for the multi-injection process (S32: NO), the CPU 52 substitutes "KAF, Kw, Qb" for the requested injection amount Qd (S48). Next, the CPU 52 calculates the injection start timing Isin of the single injection (S50). Specifically, as shown in FIG. 3B, the CPU 52 sets the timing at which the intake valve 18 is advanced by a predetermined amount Δ1 with respect to the valve opening start timing as the arrival end timing AEns. Next, the CPU 52 sets the timing advanced with respect to the arrival end time AEs by the value obtained by adding the injection period by the port injection valve 16 determined from the required injection amount Qd and the flight time and the invalid injection time as the injection start time Isin. do. Returning to FIG. 5, the CPU 52 outputs the operation signal MS2 to the port injection valve 16 to inject the fuel of the required injection amount Qd at the injection start time Isin to operate the port injection valve 16 (S46).

The CPU 52 temporarily ends the series of processes shown in FIG. 5 when the process of S46 is completed or when a negative determination is made in S30.

Here, the operation and effect of this embodiment will be described.

The CPU 52 variably sets the injection start timing Is of the intake synchronous injection based on the water temperature THW, the rotation speed NE, and the intake phase difference DIN within a predetermined period after the starter is turned on. Further, after a predetermined period has elapsed after the starter is turned on, the CPU 52 variably sets the injection start timing Is of the intake synchronous injection based on the rotation speed NE, the filling efficiency η, and the water temperature THW. As a result, as compared with the case where the injection start timing Is of the intake synchronous injection is fixed, it is possible to adjust to the optimum timing for suppressing the PN, so that the PN can be suppressed.

According to the present embodiment described above, the effects described below can be further obtained.

(1) When a predetermined period elapses after the starter is turned on, the CPU 52 sets the injection start time Is based on the arrival end time AEs. Here, it has been found by the inventor that the appropriate timing for suppressing PN is determined by the timing when the fuel injected from the port injection valve 16 at the latest timing reaches the inlet IN of the combustion chamber 24. .. Then, the injection start time Is is not uniquely determined from the above timing of reaching the inlet IN, and depends on the synchronous injection amount Qs and the like. Here, the synchronous injection amount Qs is calculated according to the rotation speed NE, the water temperature THW, the filling efficiency η, and the intake phase difference DIN. Therefore, when the injection start time Is is directly obtained without obtaining the arrival end time AEs, it is necessary to perform high-dimensional matching including at least all the parameters used for calculating the synchronous injection amount Qs, and the matching man-hours become large. .. On the other hand, by using the arrival end time AEs, the relationship between the two-dimensional parameters of the rotation speed NE and the filling efficiency η and the arrival end time AEs can be matched, and the one-dimensional parameter of the water temperature THW and the water temperature correction coefficient Kthw can be obtained. In this embodiment, the number of conforming steps can be reduced because the conforming of the relationship is sufficient.

<Second embodiment>
Hereinafter, the second embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

FIG. 6 shows the relationship between the arrival end time and PN and HC. Specifically, FIG. 6A shows a case where the overlap amount is zero, and FIG. 6B shows a case where the overlap amount is larger than zero by advancing the valve opening start timing of the intake valve 18. Indicates the case where it is.

As shown in FIG. 6, when the intake valve 18 is advanced to increase the overlap amount, the optimum arrival end time for suppressing PN shifts to the advance side. This is because the fluid in the combustion chamber 24 is blown back to the intake passage 12 during the period when both the intake valve 18 and the exhaust valve 30 are open, so that the intake system is warmed and the fuel in the intake system is easily vaporized. It is also considered that this is because the amount of fuel that adheres to and stays in the intake system without flowing into the combustion chamber 24 is reduced.

Therefore, in the present embodiment, the arrival end time AEs is not directly matched, but the retard angle amount ΔAEs of the arrival end time AEs with respect to the valve opening start time of the intake valve 18 is matched. As a result, the arrival end time AEs becomes the time on the advance side as the intake phase difference DIN becomes on the advance side.

Note that FIG. 6A shows a case where the water temperature THW is 0 °, 20 °, and 40 °, respectively, and FIG. 6B shows a case where the water temperature THW is 0 ° and 20 °, respectively. Is shown. FIG. 6 shows that when the water temperature THW is low, PN can be suppressed by setting the arrival end time AEs to the retard side, which is the setting of the water temperature correction coefficient Kthw in the treatment of S40 in FIG. Is consistent with.

FIG. 7 shows a procedure of the injection valve operation process M30 according to the present embodiment. The process shown in FIG. 7 is realized by the CPU 52 repeatedly executing the program stored in the ROM 54, for example, at a predetermined cycle. In FIG. 7, the same step numbers are assigned to the processes corresponding to the processes shown in FIG. 5 for convenience.

In the series of processes shown in FIG. 7, when the process of S36 is completed, the CPU 52 calculates the retard angle amount ΔAEs based on the rotation speed NE and the filling efficiency η (S38a). Next, the CPU 52 substitutes the value obtained by multiplying the retard angle amount ΔAEs calculated in S38a by the water temperature correction coefficient Kthw into the retard angle amount ΔAEs (S40a). Then, the CPU 52 determines the port injection valve 16 determined from the synchronous injection amount Qs with respect to the arrival end time AEs, which is the timing retarded by the retard angle ΔAEs with respect to the valve opening start time of the intake valve 18 determined from the intake phase difference DIN. The timing at which the angle is advanced by the sum of the injection period, the flight time, and the invalid injection time according to the above is defined as the injection start time Is (S42a). Then, the CPU 52 shifts to the process of S44.

As described above, according to the present embodiment, since the arrival end time AEs is determined by the retard angle amount ΔAEs, the arrival end time AEs is closer to the advance side as the valve opening start time of the intake valve 18 becomes the advance side. It is a value. This reflects the tendency shown in FIG.

When the intake phase difference DIN is determined from the rotation speed NE and the filling efficiency η, the intake phase difference is determined by determining the arrival end time AEs according to the rotation speed NE and the filling efficiency η as in the first embodiment. As the DIN becomes the advance side, the arrival end time AEs is adapted to the value on the advance side. However, even if the internal combustion engine 10 is the same, the setting of the intake phase difference DIN according to the rotation speed NE and the filling efficiency η may differ depending on the vehicle type installed, and the only reason is that the setting is changed in that case. Reconciliation of AEs at the end of arrival will increase the number of conforming man-hours. On the other hand, in the present embodiment, by matching the retard angle amount ΔAEs, even if the intake phase difference DIN is set differently according to the rotation speed NE and the filling efficiency η, the intake phase difference DIN is set. It becomes possible to share the retard angle amount ΔAEs between those having different values.

<Third embodiment>
Hereinafter, the third embodiment will be described with reference to the drawings, focusing on the differences from the first embodiment.

FIG. 8 shows the procedure of the injection valve operation process M30 according to the present embodiment. The process shown in FIG. 8 is realized by the CPU 52 repeatedly executing the program stored in the ROM 54, for example, at a predetermined cycle. In FIG. 8, the same step numbers are assigned to the processes corresponding to the processes shown in FIG. 5 for convenience.

In the series of processes shown in FIG. 8, when the process of S36 is completed, the CPU 52 selectively executes one of the following processes according to the value of the water temperature THW (described as THW1, ... THWn in the figure). (S38b). Here, the first process is a process of performing a map calculation of the arrival end time AEs based on the map data using the rotation speed NE, the filling efficiency η, and the intake phase difference DIN as input variables and the arrival end time AEs as output variables. The second process is a process of performing a map calculation of the retarded amount ΔAEs based on the map data in which the rotation speed NE and the filling efficiency η are used as input variables and the retard angle amount ΔAEs is used as the output variable. Here, in the first process, the arrival end time AEs is not necessarily the optimum arrival end time AEs for suppressing PN by advancing the arrival end time AEs in proportion to the advance angle amount of the intake valve 18 valve opening start time. It is carried out in the water temperature region where there is a concern that it will not be.

Next, the CPU 52 executes a process according to the process of S42a of FIG. 7 or the process of S42 of FIG. 5 depending on whether the retard angle amount ΔAEs is calculated or the arrival end time AEs is calculated in the process of S38b. S42b). When the process of S42b is completed, the CPU 52 shifts to the process of S44.

As described above, in the present embodiment, in the water temperature region where it is difficult to optimize from the viewpoint of suppressing PN by determining the arrival end time AEs in proportion to the advance angle amount of the intake valve 18 valve opening start time. The conforming values of the arrival end time AEs according to the rotation speed NE, the filling efficiency η, and the intake phase difference DIN are used. Therefore, the PN can be further reduced while suppressing the increase in the conforming man-hours. Further, by setting the arrival end time AEs based on the intake phase difference DIN, for example, when the water temperature THW is low, the intake phase difference DIN is not set to a value corresponding to the rotation speed NE and the filling efficiency η, and an exception is made. Even when the value is set on the retard side, it can be set to an appropriate value for suppressing PN.

<Correspondence>
The correspondence between the matters in the above-described embodiment and the matters described in the above-mentioned "means for solving the problem" column is as follows. In the following, the correspondence is shown for each number of the solution means described in the column of "Means for solving the problem". [1, 2] The multi-injection process corresponds to the process of S22 via the process of S20 in FIG. 4 and the process of S46 via the process of S44 in FIG. The variable processing includes the processing of S18 in FIG. 4, the processing of S38 to S42 in FIG. 5, the processing of S38a to S42a in FIG. 7, and the processing of S38b and S42 in FIG.
Corresponds to the processing of b. [2] The required injection amount calculation process corresponds to the base injection amount calculation process M20, the feedback process M22, and the low temperature correction process M24. That is, since the required injection amount Qd is "Qb, KAF, Kw", the required injection amount is calculated by calculating the base injection amount Qb, the feedback correction coefficient KAF, and the low temperature increase coefficient Kw by each of the above processes. It can be considered that Qd has been calculated. [3, 5, 6] The end time setting process corresponds to the process of S38 and S40 in FIG. 5, the process of S38a and S40a in FIG. 7, and the process of S38b in FIG. That is, since the arrival end time is the timing retarded by the retard angle ΔAEs with respect to the valve opening start time of the intake valve 18 determined from the intake phase difference DIN, refer to the intake phase difference DIN in the processing of S42a and S42b. It can be considered that this is the timing retarded by the retard angle amount ΔAEs with respect to the valve opening start timing of the intake valve 18. The start time calculation process corresponds to the process of S42 of FIG. 5, the process of S42a of FIG. 7, and the process of S42b of FIG. [4,7] The valve characteristic variable device corresponds to the intake side valve timing adjusting device 44, and the valve characteristic control process corresponds to the target intake phase difference calculation process M12 and the intake phase difference control process M14. The retard angle amount calculation process corresponds to the processes of S38a and S38b.

<Other Embodiments>
In addition, this embodiment can be implemented by changing as follows. The present embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.

・ "About start time calculation process"
In the above embodiment, the injection start time Is is calculated in consideration of the fact that the invalid injection time depends on the terminal voltage Vb, but the present invention is not limited to this. For example, the invalid injection time may be a fixed value.

・ "About the end time calculation process"
In FIG. 7, the retardation amount ΔAEs was map-calculated using the map data with the rotation speed NE and the filling efficiency η as the input variables and the retard angle amount ΔAEs as the output variable, and this was corrected based on the water temperature THW. Not exclusively. For example, map calculation may be performed using map data in which the rotation speed NE, the filling efficiency η, and the water temperature THW are input variables, and the retard angle amount ΔAEs is the output variable.

In FIG. 8, only when the water temperature THW enters a predetermined temperature range, the arrival end time is reached using map data with the rotation speed NE, the filling efficiency η, and the intake phase difference DIN as input variables and the arrival end time AEs as output variables. Map calculation of AEs is performed, but it is not limited to this. For example, regardless of the water temperature THW, the arrival end time AEs is map-calculated using the map data with the rotation speed NE, the filling efficiency η, and the intake phase difference DIN as the input variables and the arrival end time AEs as the output variable, and this is used as the water temperature THW. It may be corrected according to. Alternatively, instead of this, the arrival end time AEs may be mapped using map data using the rotation speed NE, the filling efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and the arrival end time AEs as output variables. good.

・ "About variable processing"
(A) Within a predetermined period after the starter is turned on In FIG. 4, the injection start time is mapped based on the map data with the rotation speed NE, the water temperature THW, and the intake phase difference DIN as the input variables and the injection start time as the output variable. Not limited to. For example, the injection start time may be mapped based on the map data in which the rotation speed NE and the intake phase difference DIN are used as the input variables and the injection start time is used as the output variable, and this may be corrected based on the water temperature THW. Further, for example, the injection start time is calculated based only on the rotation speed NE and the water temperature THW regardless of the intake phase difference DIN, or the injection start time is calculated based on the rotation speed NE and the intake phase difference DIN regardless of the water temperature THW. Alternatively, the injection start time may be calculated based on the water temperature THW and the intake phase difference DIN regardless of the rotation speed NE.
Instead of using the intake phase difference DIN *, the target intake phase difference DIN * may be used.

(B) After a predetermined period has elapsed after the starter is turned on In the above embodiment, the arrival end time AEs is set based on the rotation speed NE, the filling efficiency η, the water temperature THW, and the like, but the present invention is not limited to this. As a parameter indicating the amount of fresh air filled in the combustion chamber 24 (parameter indicating the load), for example, the base injection amount Qb may be used instead of the filling efficiency η. Further, regarding the four parameters of the rotation speed NE, the load, the water temperature THW, and the intake phase difference DIN, the arrival end time AEs can be variably set based on only three of these parameters in addition to the above embodiment, or 2 It may be variably set based on only one parameter.

It is not limited to the one that calculates the injection start time Is after calculating the arrival end time AEs and the retard angle amount ΔAEs. For example, the injection start time Is may be calculated based on the map data in which the rotation speed NE and the filling efficiency η are used as input variables and the injection start time Is is used as an output variable. In this case, the calculated injection start time Is may be corrected according to the water temperature THW. Further, for example, the injection start time Is may be calculated based on the map data in which the rotation speed NE, the filling efficiency η, and the intake phase difference DIN are used as input variables and the injection start time Is is used as an output variable. In this case, the calculated injection start time Is may be corrected according to the water temperature THW. Further, for example, the injection start time Is may be calculated based on the map data in which the rotation speed NE, the filling efficiency η, the intake phase difference DIN, and the water temperature THW are input variables and the injection start time Is is an output variable.

Instead of using the intake phase difference DIN *, the target intake phase difference DIN * may be used. Further, the calculated injection start time Is may be corrected according to the terminal voltage Vb.

・ "About the temperature of the intake system"
In the above configuration, the water temperature THW is used as the temperature of the intake system, but the temperature is not limited to this. For example, the temperature of the lubricating oil of the internal combustion engine 10 may be used.

・ "Required injection amount"
The required injection amount Qd may be corrected by the learning value LAF in addition to the low temperature increase coefficient Kw and the feedback correction coefficient KAF. Incidentally, the calculation process of the learning value LAF is a process of inputting the feedback correction coefficient KAF and updating the learning value LAF so that the correction ratio of the base injection amount Qb by the feedback correction coefficient KAF becomes small. It is desirable that the learning value LAF is stored in an electrically rewritable non-volatile memory.

Further, for example, the required injection amount Qd may be calculated so that the required injection amount Qd becomes smaller when the disturbance fuel ratio is large than when it is small, by feedforward control based on the disturbance fuel ratio. Here, the disturbance fuel ratio means that the amount of fuel (disturbance fuel) that flows into the combustion chamber 24 of the internal combustion engine 10 other than the fuel injected from the port injection valve 16 in one combustion cycle flows into the combustion chamber 24. It is the ratio to the total amount of fuel. Further, as the disturbance fuel, for example, a canister that collects fuel vapor from a fuel tank that stores fuel injected from the port injection valve 16 and an adjusting device that adjusts the inflow amount of the fluid in the canister into the intake passage 12. When the internal combustion engine is provided with the above, there is fuel steam flowing into the intake passage 12 from the canister. Further, for example, when a system for returning the fuel vapor in the crankcase to the intake passage 12 is provided, there is fuel vapor flowing into the intake passage 12 from the crankcase.

・ "About intake asynchronous injection"
In the above embodiment, the intake asynchronous injection is performed so that the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 falls within the valve closing period of the intake valve 18. However, it is not limited to this. For example, when the rotation speed NE is high and the asynchronous injection amount Qns is excessively large, the intake valve 18 is opened for a part of the period during which the fuel injected from the port injection valve 16 reaches the position before the intake valve 18 is opened. It may overlap with the valve period.

・ "About single injection processing"
In the above embodiment, the single injection process is performed so that the period during which the fuel injected from the port injection valve 16 reaches the position before the intake valve 18 is opened falls within the valve closing period of the intake valve 18. However, it is not limited to this. For example, when the required injection amount Qd is large, a part of the period during which the fuel injected from the port injection valve 16 reaches the position before the opening of the intake valve 18 overlaps with the valve opening period of the intake valve 18. There may be. It is not essential to execute the single injection process.

・ "About the method of dividing the required injection amount"
In the above embodiment, the synchronous injection amount Qs is variably set based on the rotation speed NE, the filling efficiency η, the water temperature THW, and the intake phase difference DIN, but the present invention is not limited to this. For example, the base injection amount Qb may be used instead of the filling efficiency η as the load parameter which is a parameter indicating the amount of fresh air filled in the combustion chamber 24. Further, the four parameters of the load parameter, the rotation speed NE, the water temperature THW, and the intake phase difference DIN can be variably set based on only three of them, or variably set based on only two parameters. It may be variably set based on only one parameter. At this time, it is desirable to variably set the load parameter and the water temperature THW by using at least one as much as possible. In addition to the above four parameters, for example, the intake pressure and the flow velocity of the intake air may be used. However, according to the above four parameters, the intake pressure and the flow velocity of the intake air can be grasped.

Further, it is not essential to calculate the synchronous injection amount Qs itself, and for example, the synchronous injection ratio Ks, which is the ratio of the synchronous injection amount Qs to the base injection amount Qb, may be determined according to a load or the like. Further, for example, the value "KAF · Qb" in which the base injection amount Qb is corrected by the feedback correction coefficient KAF may be divided by the synchronous injection ratio Ks to obtain the synchronous injection amount Qs. In this case, the synchronous injection amount Qs is "Ks, KAF, Qb".

・ "Valve characteristic control processing"
In the above embodiment, the target intake phase difference DIN * is variably set according to the rotation speed NE and the filling efficiency η, but the present invention is not limited to this. For example, as mentioned in the third embodiment, for example, when the water temperature THW is low, the actual timing with respect to the valve opening timing of the intake valve 18 which is exceptionally determined according to the rotation speed NE and the filling efficiency η. May be limited to the retard side.

・ "About the variable intake valve characteristics device"
The characteristic variable device for changing the characteristics of the intake valve 18 is not limited to the intake side valve timing adjusting device 44. For example, the lift amount of the intake valve 18 may be changed. In this case, the parameter indicating the valve characteristics of the intake valve 18 is the lift amount or the like instead of the intake phase difference DIN.

・ "About control device"
The control device is not limited to the one that includes the CPU 52 and the ROM 54 and executes software processing. For example, a dedicated hardware circuit (for example, ASIC or the like) that performs hardware processing on at least a part of what has been software-processed in the above embodiment may be provided. That is, the control device may have any of the following configurations (a) to (c). (A) A processing device that executes all of the above processing according to the program, and an R that stores the program.
It is equipped with a program storage device such as an OM. (B) A processing device and a program storage device that execute a part of the above processing according to a program, and a dedicated hardware circuit that executes the remaining processing are provided. (C) A dedicated hardware circuit for executing all of the above processes is provided. Here, there may be a plurality of software processing circuits including a processing device and a program storage device, and a plurality of dedicated hardware circuits. That is, the processing may be executed by a processing circuit including at least one of one or more software processing circuits and one or more dedicated hardware circuits.

·"others"
It is not essential that the internal combustion engine 10 is provided with a characteristic variable device that changes the characteristics of the intake valve 18. It is not essential that the internal combustion engine 10 includes the throttle valve 14.

When the vehicle on which the internal combustion engine 10 is mounted is equipped with a rotary electric machine as a prime mover for generating the thrust of the vehicle, the rotary electric machine may be used as a means for imparting initial rotation to the crankshaft 28 instead of the starter motor 36. good.

10 ... Internal combustion engine, 12 ... Intake passage, 14 ... Throttle valve, 16 ... Port injection valve, 18 ... Intake valve, 20 ... Cylinder, 22 ... Piston, 24 ... Combustion chamber, 26 ... Ignition device, 28 ... Crankshaft, 30 ... Exhaust valve, 32 ... Exhaust passage, 34 ... Catalyst, 36 ... Starter motor, 38 ... Timing chain, 40 ... Intake side camshaft, 42 ... Exhaust side camshaft, 44 ... Intake side valve timing adjustment device, 50 ... Control device , 52 ... CPU, 54 ... ROM, 56 ... Power supply circuit, 60 ... Crank angle sensor, 62 ... Air flow meter, 64 ... Air fuel ratio sensor, 66 ... Intake side cam angle sensor, 68 ... Water temperature sensor, 70 ... Battery, 72 ... Voltage sensor.

Claims (7)

Applicable to internal combustion engines equipped with a port injection valve that injects fuel into the intake passage
Intake synchronous injection in which fuel is injected in synchronization with the valve opening period of the intake valve in order to inject fuel in the required injection amount, which is the injection amount required in one combustion cycle, by operating the port injection valve. Multi-injection processing that executes intake asynchronous injection that injects fuel at a timing on the advance side of the intake synchronous injection, and
The injection timing of the intake synchronous injection expressed by the rotation angle of the crankshaft of the internal combustion engine is changed by the rotation speed of the crankshaft of the internal combustion engine and the amount of overlap between the intake valve and the exhaust valve. A control device for an internal combustion engine that executes variable processing for variably setting based on at least two parameters of the valve opening start time and the temperature of the intake system of the internal combustion engine.
Based on the fresh air amount filled in the cylinder of the internal combustion engine, the required injection amount calculation process for calculating the required injection amount as the injection amount for controlling the air-fuel ratio to the target air-fuel ratio is executed.
The control device for an internal combustion engine according to claim 1, wherein the variable processing is a processing for variably setting the injection timing of the intake synchronous injection based on the load of the internal combustion engine in addition to the at least two parameters. The variable processing is
Based on the rotation speed, the temperature of the intake system, and the load, the arrival end time, which is the target value of the timing at which the fuel injected from the port injection valve at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine, is set. Variable setting end time setting process and
The control device for an internal combustion engine according to claim 2, further comprising a start time calculation process for calculating the injection start time of the intake synchronous injection based on the arrival end time. The internal combustion engine includes a valve characteristic variable device that changes the valve characteristics of the intake valve.
A valve characteristic control process for variably controlling the valve opening start timing of the intake valve is executed by operating the valve characteristic variable device.
The end time setting process includes a retard angle amount calculation process for calculating the retard angle amount of the arrival end time with respect to the valve opening start time based on the rotation speed, the temperature of the intake system, and the load, and the valve opening time setting process. The control device for an internal combustion engine according to claim 3, wherein the timing retarded by the retard angle with respect to the start timing is set as the arrival end timing. Applicable to internal combustion engines equipped with a port injection valve that injects fuel into the intake passage
Intake synchronous injection in which fuel is injected in synchronization with the valve opening period of the intake valve in order to inject fuel in the required injection amount, which is the injection amount required in one combustion cycle, by operating the port injection valve. Multi-injection processing that executes intake asynchronous injection that injects fuel at a timing on the advance side of the intake synchronous injection, and
A variable process for variably setting the injection timing of the intake synchronous injection expressed by the rotation angle of the crankshaft of the internal combustion engine is executed.
The variable processing is
Based on the rotation speed of the crankshaft, the end time setting that variably sets the arrival end time, which is the target value of the timing at which the fuel injected from the port injection valve at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine. Processing and
A control device for an internal combustion engine, which includes a start time calculation process for calculating an injection start time of the intake synchronous injection based on the arrival end time. The control device for an internal combustion engine according to claim 5, wherein the end time setting process includes a process for variably setting the arrival end time based on the load of the internal combustion engine in addition to the rotation speed. The internal combustion engine includes a valve characteristic variable device that changes the valve characteristics of the intake valve.
A valve characteristic control process for variably controlling the valve opening start timing of the intake valve is executed by operating the valve characteristic variable device.
The end time setting process includes a retard angle amount calculation process for calculating the retard angle amount of the arrival end time with respect to the valve opening start time based on the rotation speed and the load, and the valve opening start time is described as described above. The control device for an internal combustion engine according to claim 6, wherein the timing of retarding by the amount of retardation is set as the arrival end time.

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