CN111065809B

CN111065809B - Control device and control method for internal combustion engine

Info

Publication number: CN111065809B
Application number: CN201880056840.6A
Authority: CN
Inventors: 丹羽隆彦; 户谷将典; 吉田享史; 大町孝之
Original assignee: Toyota Motor Corp
Current assignee: Toyota Motor Corp
Priority date: 2017-09-05
Filing date: 2018-08-23
Publication date: 2022-04-01
Anticipated expiration: 2038-08-23
Also published as: CN111065809A; WO2019049676A1

Abstract

The multiple injection process performs intake-synchronized injection and intake-unsynchronized injection for injecting fuel of a required injection quantity (Qd) by operating a port injection valve (16) that injects fuel into an intake passage (12). The variable processing variably sets an injection timing (Is) of the intake-synchronized injection based on at least two of the three parameters. The injection timing of the intake-synchronized injection is expressed by the rotation angle of a crankshaft (28) of the internal combustion engine (10). The three parameters are the rotational speed (NE) of the crankshaft of the internal combustion engine, the opening start timing (DIN, AEs) of the intake valve (18), and the Temperature (THW) of the intake system of the internal combustion engine (10).

Description

Control device and control method for internal combustion engine

Technical Field

The present disclosure relates to a control device and a control method for an internal combustion engine. The control device and the control method are applied to an internal combustion engine provided with a port injection valve that injects fuel into an intake passage. The internal combustion engine may further include a catalyst that purifies exhaust gas discharged to the exhaust passage.

Background

For example, a control device described in patent document 1 executes a multi-injection process in which fuel injected into one cylinder in one combustion cycle is distributed and injected in an exhaust stroke and an intake stroke. According to paragraphs [0017] and [0024] of the document, the control device sets the injection timing in the intake stroke to a predetermined timing.

For example, a control device described as a second embodiment in patent document 2 injects fuel in an amount (required injection amount) required for one combustion cycle determined from an intake air amount in a high load range in two divided portions.

Prior art documents

Patent document

Patent document 1: japanese patent laid-open publication No. 2005-291133

Patent document 2: japanese patent laid-open publication No. 2015-59456

Disclosure of Invention

Problems to be solved by the invention

Fixing the injection timing may be problematic in terms of good control of exhaust gas composition.

Means for solving the problems

Examples of the present disclosure are described below.

Example 1. a control apparatus for an internal combustion engine, wherein,

the control device is applied to an internal combustion engine provided with a port injection valve that injects fuel into an intake passage,

the control device is configured to execute:

a multiple injection process of performing an intake-synchronized injection and an intake-unsynchronized injection by operating the port injection valve in order to inject a required injection amount of fuel in one combustion cycle, the required injection amount being an injection amount required in one combustion cycle, the intake-synchronized injection injecting fuel in synchronization with a valve-opening period of an intake valve, the intake-unsynchronized injection injecting fuel at a timing at an advanced side with respect to the intake-synchronized injection; and

and a variable process of variably setting an injection timing of the intake-synchronized injection, which is expressed by a rotation angle of a crankshaft of the internal combustion engine, based on at least two parameters among three parameters, which are a rotation speed of the crankshaft of the internal combustion engine, a valve-opening start timing of the intake valve, and a temperature of an intake system of the internal combustion engine.

When the temperature of the intake system of the internal combustion engine is low, if all of the fuel of the required injection amount is injected by the intake-unsynchronized injection, the number (PN) of Particulate Matter (PM) in the exhaust gas may increase due to the load. The reason for this is presumed to be that PM is generated because the amount of fuel adhering to the intake system increases, and a part of the adhering fuel is sheared and flows directly into the combustion chamber in the form of droplets. Therefore, in the above-described structure, a part of the required injection amount is injected by the intake-synchronized injection. Therefore, the asynchronous injection amount is reduced, and the amount of fuel adhering to the intake system is reduced. That is, the fuel can be prevented from directly flowing into the combustion chamber in a droplet state due to shearing of the adhering fuel.

However, the inventors have found that the number (PN) of Particulate Matter (PM) in the exhaust gas greatly varies depending on the injection timing in the intake stroke. Therefore, for example, fixing the injection timing may have a problem in terms of well controlling the exhaust gas composition. The above structure deals with such a problem.

That is, the inventors have found that the injection timing of the intake-synchronized injection for minimizing PN varies depending on the rotation speed of the crankshaft. The reason for this is presumed to be that the amount of fuel that does not flow into the combustion chamber and adheres to the intake system and remains tends to change due to a change in the flow speed in the intake passage or the like depending on the rotation speed. It is assumed that the amount of rotation of the crankshaft changes during a period until a predetermined amount of fuel in the fuel injected from the port injection valves vaporizes. In contrast, in the above configuration, if the injection timing of the intake-synchronized injection is variably set according to the rotation speed, PN can be suppressed as compared with a case where the injection timing is not variable according to the rotation speed, for example.

The inventors have also found that the injection timing of the intake-synchronized injection for minimizing PN varies depending on the valve-opening start timing of the intake valve. The reason for this is presumed to be that the internal EGR amount changes due to a change in the overlap amount of the intake valve and the exhaust valve when the opening start timing of the intake valve is changed, and therefore the temperature of the intake system rises and the degree of vaporization of the fuel in the intake system changes. The cause is estimated to be a change in the amount of fuel that does not flow into the combustion chamber, adheres to the intake system, and is accumulated. In contrast, in the above configuration, if the injection timing of the intake-synchronized injection is variably set in accordance with the valve-opening start timing of the intake valve, PN can be suppressed as compared with a case where the injection timing is not variably set in accordance with the valve-opening start timing of the intake valve, for example.

Also, the inventors have found that the injection timing of the intake-synchronized injection for minimizing PN varies depending on the temperature of the intake system. The reason is presumably because the degree of ease of vaporization of the fuel in the intake system differs depending on the temperature of the intake system. In contrast, in the above configuration, if the injection timing of the intake-synchronized injection is variably set in accordance with the temperature of the intake system, PN can be suppressed as compared with, for example, a case where the injection timing is not variable in accordance with the temperature of the intake system.

Example 2. in the control device of the above example 1, the control device is configured to further execute a required injection amount calculation process of calculating the required injection amount as an injection amount for controlling an air-fuel ratio to a target air-fuel ratio based on an amount of fresh air charged into a cylinder of the internal combustion engine,

the variable processing is processing for variably setting the injection timing of the intake-air synchronized injection based on the load of the internal combustion engine in addition to the at least two parameters.

The inventors have found that the injection timing for minimizing PN varies depending on the load of the internal combustion engine. The reason for this is presumably because the ease of atomization of the fuel changes due to a change in the amount of fuel injected according to the load or a change in the pressure in the intake passage. Therefore, in the above-described structure, the injection timing of the intake-synchronized injection is variably set in accordance with the load. Therefore, PN can be suppressed as compared with the case where the PN is not variable according to the load, for example.

Example 3 in the control device of the above example 2, the variable processing includes:

an end timing setting process of variably setting an end-to-end timing, which is a target value of a timing at which fuel injected from the port injection valve reaches an inlet of a combustion chamber of the internal combustion engine at the latest timing, based on the rotation speed, the temperature of the intake system, and the load; and

and a start timing calculation process of calculating an injection start timing of the intake-synchronized injection based on the arrival-at-end timing.

The inventors have found that PN varies greatly in accordance with variation in timing at which fuel injected at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine, and that even if the injection ratio of the intake-synchronized injection and the intake-unsynchronized injection is slightly changed, the optimum timing hardly changes in terms of suppressing PN. Therefore, in the above-described structure, the injection start timing of the intake-synchronized injection is set after the reaching end timing is set. Therefore, the timing appropriate for suppressing PN can be managed according to the arrival end timing, which is a parameter handled by the control device.

Example 4. in the control device of the above example 3, the internal combustion engine includes a valve characteristic varying device configured to vary the valve characteristic of the intake valve,

the control device is configured to further execute a valve characteristic control process of variably controlling a valve opening start timing of the intake valve by operating the valve characteristic variable device,

the end timing setting process includes a retard amount calculation process of calculating a retard amount of the end timing of the arrival with respect to a valve opening start timing of the intake valve based on the rotation speed, a temperature of the intake system, and the load,

the end timing setting process is a process of setting the end timing to the end timing at a timing delayed by the retard amount with respect to the valve opening start timing of the intake valve.

The inventors have found that the injection timing of the intake-synchronized injection for reducing PN as much as possible varies depending on the valve-opening start timing of the intake valve. The reason for this is presumed to be that the internal EGR amount changes due to a change in the overlap amount of the intake valve and the exhaust valve when the opening start timing of the intake valve is changed, and therefore, the degree of easiness of vaporization of the fuel in the intake system changes due to an increase in the temperature of the intake system, or the amount of fuel that adheres to the intake system without flowing into the combustion chamber and remains changes. Therefore, in the above configuration, the injection timing of the intake-synchronized injection is variably set in accordance with the valve-opening start timing of the intake valve. Therefore, PN can be suppressed as compared with the case where the opening start timing of the intake valve is not changed, for example.

In particular, in the above configuration, the arrival completion timing is not directly calculated, but the retard amount of the arrival completion timing with respect to the valve opening start timing of the intake valve is first calculated. Therefore, the parameter used for calculating the retard angle amount does not use the opening start timing of the intake valve, and the reaching end timing can be variably set in accordance with the opening start timing of the intake valve.

Example 5 in the control device of the above example 1 or 2, the variable processing includes:

an end timing setting process of variably setting an end-to-end timing, which is a target value of a timing at which fuel injected from the port injection valves reaches an inlet of a combustion chamber of the internal combustion engine at the latest timing, based on a rotation speed of the crankshaft; and

When the temperature of the intake system of the internal combustion engine is low, if all of the fuel of the required injection amount is injected by the intake-unsynchronized injection, the number (PN) of Particulate Matter (PM) in the exhaust gas may increase due to the load. The reason for this is presumed to be that PM is generated because the amount of fuel adhering to the intake system increases, and a part of the adhering fuel is sheared and flows directly into the combustion chamber in the form of droplets. Therefore, in the above configuration, a part of the required injection amount is injected by the synchronized injection. Therefore, the asynchronous injection amount is reduced, and the amount of fuel adhering to the intake system is reduced. Therefore, the fuel can be prevented from directly flowing into the combustion chamber in a droplet state due to shearing of the adhering fuel.

However, the inventors have found that PN varies greatly in accordance with variation in timing at which fuel injected at the latest timing reaches the inlet of the combustion chamber of the internal combustion engine, and that even if the injection ratio of the intake-synchronized injection and the intake-unsynchronized injection is slightly changed, the optimum timing hardly changes in terms of suppressing PN. Therefore, in the above-described structure, the injection start timing is set after the reaching end timing is set. Therefore, the timing appropriate for suppressing PN can be managed according to the arrival end timing, which is a parameter handled by the control device.

In addition, the inventors have found that the end-of-arrival timing for minimizing PN varies depending on the rotation speed of the crankshaft. The reason for this is that, since the flow speed in the intake passage changes depending on the rotation speed, the amount of fuel that does not flow into the combustion chamber and adheres to the intake system and remains tends to change. It is estimated that the amount of rotation of the crankshaft changes during a period until a predetermined amount of fuel in the fuel injected from the port injection valves vaporizes. Therefore, in the above configuration, the end-of-arrival timing is variably set according to the rotation speed. Therefore, PN can be suppressed as compared with the case where the rotation speed is not varied, for example.

Example 6 in the control device of the above example 5, the end timing setting process includes a process of variably setting the end-to-end timing based on a load of the internal combustion engine in addition to the rotation speed.

The inventors have found that the end-of-arrival timing for minimizing PN varies depending on the load of the internal combustion engine. The reason for this is presumably because the degree of ease of atomization of the fuel changes due to a change in the amount of fuel injected according to the load or a change in the pressure in the intake passage. Therefore, in the above configuration, the arrival end timing is variably set in accordance with the load. Therefore, PN can be suppressed as compared with the case where the PN is not variable according to the load, for example.

Example 7. in the control device of the above example 6, the internal combustion engine includes a valve characteristic varying device configured to vary the valve characteristic of the intake valve,

the control device executes a valve characteristic control process of variably controlling a valve opening start timing of the intake valve by operating the valve characteristic variable device,

the end timing setting process includes a retard amount calculation process of calculating a retard amount of the end timing of the arrival with respect to a valve opening start timing of the intake valve based on the rotation speed and the load,

The inventors have found that the arrival end timing for reducing PN as much as possible varies depending on the valve opening start timing of the intake valve. The reason for this is presumed to be that the internal EGR amount changes due to a change in the overlap amount of the intake valve and the exhaust valve when the opening start timing of the intake valve is changed, and therefore, the degree of easiness of vaporization of the fuel in the intake system changes due to an increase in the temperature of the intake system, or the amount of fuel that adheres to the intake system without flowing into the combustion chamber and remains changes. Therefore, in the above configuration, the reaching end timing is variably set in accordance with the valve opening start timing of the intake valve. Therefore, PN can be suppressed as compared with the case where the opening start timing of the intake valve is not changed, for example.

In particular, in the above configuration, the arrival completion timing is not directly calculated, but the retard amount of the arrival completion timing with respect to the valve opening start timing of the intake valve is first calculated. Therefore, the parameter used for calculating the retard amount to the end timing does not use the valve opening start timing of the intake valve, and the end timing can be variably set in accordance with the valve opening start timing of the intake valve.

Example 8 in the control device according to any one of examples 1 to 7, the internal combustion engine further includes a catalyst that purifies exhaust gas discharged to the exhaust passage,

the required injection amount is an amount of fuel injected from the port injection valve in the multi-injection process in order to control the air-fuel ratio to a target air-fuel ratio,

the control device is configured to further execute an advance process of advancing an injection timing of the intake-synchronized injection when the temperature of the catalyst is low, as compared with when the temperature of the catalyst is high.

The inventors have found that the injection timing of the intake-synchronous injection that is optimal in terms of suppressing PN is on the retarded side compared to the injection timing of the intake-synchronous injection that is optimal in terms of suppressing HC. Therefore, in the above configuration, the injection timing of the intake-synchronized injection is advanced at a low temperature of the catalyst where the HC purification performance of the catalyst is low, as compared with a high temperature of the catalyst where the HC purification performance is high. Therefore, it is possible to set the injection timing appropriate for suppressing the HC concentration in the exhaust gas when the purification performance of the HC in the exhaust gas is low, and set the injection timing appropriate for suppressing the PN when the HC can be purified even when the HC concentration in the exhaust gas is high.

The inventors studied a multi-injection process in which a part of a required injection amount is injected by intake-synchronized injection that is injected in synchronization with a valve-open period of an intake valve and the remaining part is injected by intake-unsynchronized injection that is advanced in angle from the intake-synchronized injection in order to reduce PN, which is the number of Particulate Matter (PM) in exhaust gas. The inventors have also found that the number (PN) of Particulate Matter (PM) in the exhaust gas greatly varies depending on the injection timing in the intake stroke. The inventors have also found that when the injection timing of the intake-synchronized injection is set to a timing appropriate for suppressing PN, there is a possibility that the HC concentration in the exhaust gas increases. The above structure deals with this possibility.

Example 9 in the control device of the above example 8, the internal combustion engine includes a valve characteristic varying device for varying a valve characteristic of the intake valve,

the variable processing variably sets the injection timing of the intake-synchronized injection in accordance with the valve-opening start timing of the intake valve.

The variable processing includes:

a reference timing setting process of setting an injection timing of the intake-synchronized injection based on a valve-opening start timing of the intake valve;

a guard value setting process of setting a hysteresis guard value in a case where a temperature of the catalyst is less than a predetermined value, in accordance with a temperature of an intake system of the internal combustion engine; and

a low temperature timing setting process of setting, when the temperature of the catalyst is lower than the predetermined value, an injection timing of the intake-synchronized injection to be a timing at a more advanced side of the injection timing and the retard guard value set by the reference timing setting process,

the variable processing is processing for setting the injection timing set by the reference timing setting processing as the injection timing of the intake-synchronized injection when the temperature of the catalyst is equal to or higher than the predetermined value.

The inventors have found that the injection timing of the intake-synchronized injection for reducing PN as much as possible varies depending on the valve-opening start timing of the intake valve. The reason for this is presumed to be that the internal EGR amount changes due to a change in the overlap amount of the intake valve and the exhaust valve when the opening start timing of the intake valve is changed, and therefore, the degree of easiness of vaporization of the fuel in the intake system changes due to a temperature increase in the intake system, or the amount of fuel that adheres to the intake system without flowing into the combustion chamber and remains changes. Therefore, in the above configuration, the injection timing of the intake-synchronized injection is variably set in accordance with the valve-opening start timing of the intake valve. Therefore, PN can be suppressed as compared with the case where the opening start timing of the intake valve is not changed, for example.

When the temperature of the catalyst is low, the setting of the injection timing necessary to suppress the increase in the concentration of HC in the exhaust gas tends to be greatly influenced by the temperature of the intake system. Therefore, in the above configuration, the retard guard value is set in accordance with the temperature of the intake system. Specifically, a protection process is performed in which the retard guard value is set to a retard-side limit value with respect to the injection timing appropriate for suppressing PN, that is, the injection timing set by the reference timing setting process. Therefore, the timing appropriate in terms of suppressing PN and the timing appropriate in terms of suppressing HC can be appropriately set.

Example 10. a control apparatus for an internal combustion engine, wherein,

the control device is configured to execute:

a variable process of variably setting an injection timing of the intake-air-synchronized injection expressed by a rotation angle of a crankshaft of the internal combustion engine,

the variable processing includes:

Example 11 a control apparatus for an internal combustion engine, wherein,

an internal combustion engine to which the control device is applied includes:

an air port injection valve that injects fuel into the intake passage; and

a catalyst that purifies exhaust gas discharged to the exhaust passage,

the control device is configured to execute:

a multiple injection process of performing an intake-synchronized injection of injecting fuel in synchronization with a valve-opening period of an intake valve and an intake-unsynchronized injection of injecting fuel at a timing more advanced than the intake-synchronized injection by operating the port injection valve in order to inject fuel of a required injection amount for controlling an air-fuel ratio to a target air-fuel ratio; and

and an advance process of advancing an injection timing of the intake-air-synchronized injection when the temperature of the catalyst is low, as compared with when the temperature of the catalyst is high.

Example 12 is embodied as a method for controlling an internal combustion engine that executes the various processes described in each of examples 1 to 11.

Example 13 is embodied as a method of controlling an internal combustion engine for executing the various processes described in example 11.

Example 14 is embodied as a non-transitory computer-readable recording medium storing a program for causing a processing device to execute the various processes described in examples 1 to 11.

Example 15 the control device of the above example 8 is configured to further execute required injection amount calculation processing for calculating the required injection amount based on an amount of air charged into a cylinder of the internal combustion engine,

the variable processing includes processing for variably setting the injection timing of the intake-synchronized injection in accordance with the rotation speed of a crankshaft of the internal combustion engine and the load of the internal combustion engine in addition to the valve opening start timing of the intake valve.

The inventors have found that the injection timing of the intake-synchronized injection for minimizing PN varies depending on the rotation speed of the crankshaft. The reason is presumed to be that, because one of the reasons is that the flow speed in the intake passage changes depending on the rotation speed, the amount of fuel that does not flow into the combustion chamber and adheres to the intake system and remains tends to change. It is assumed that the amount of rotation of the crankshaft changes during a period until a predetermined amount of fuel in the fuel injected from the port injection valves vaporizes. Therefore, in the above-described structure, the injection timing of the intake-synchronized injection is variably set in accordance with the rotation speed. Therefore, PN can be suppressed as compared with the case where the rotation speed is not varied, for example.

The inventors have also found that the injection timing for minimizing PN varies depending on the load of the internal combustion engine. The reason for this is presumably that the fuel atomization easiness changes due to a change in the amount of fuel injected according to the load or a change in the pressure in the intake passage. Therefore, in the above-described structure, the injection timing of the intake-synchronized injection is variably set in accordance with the load. Therefore, PN can be suppressed as compared with the case where the PN is not variable according to the load, for example.

Example 16. in the control device of example 15, the variable processing is processing for variably setting the injection timing of the intake-synchronized injection in accordance with a temperature of an intake system of the internal combustion engine in addition to the valve opening start timing of the intake valve, the rotation speed, and the load.

The inventors have discovered that the injection timing for the intake-synchronized injection to minimize PN varies depending on the temperature of the intake system. The reason is presumably because the degree of ease of vaporization of the fuel in the intake system differs depending on the temperature of the intake system. Therefore, in the above-described structure, the injection timing of the intake-synchronized injection is variably set in accordance with the temperature of the intake system. Therefore, PN can be suppressed as compared with, for example, the case where it is not variable in accordance with the temperature of the intake system.

Drawings

Fig. 1 is a diagram showing a control device and an internal combustion engine according to a first embodiment embodying the present disclosure.

Fig. 2 is a block diagram showing processing performed by the control device in the internal combustion engine of fig. 1.

Portions (a) and (b) of fig. 3 are diagrams showing injection patterns in the internal combustion engine of fig. 1.

Fig. 4 is a flowchart showing the steps of an injection valve operation process on the basis of the internal combustion engine of fig. 1.

Fig. 5 is a flowchart showing the steps of an injection valve operation process on the basis of the internal combustion engine of fig. 1.

Fig. 6A is a diagram showing a variation in the discharge amount of PN caused by the open timing of the intake valve in the internal combustion engine of fig. 1.

Fig. 6B is a diagram showing the variation in the discharge amount of PN caused by the open timing of the intake valve in the internal combustion engine of fig. 1.

Fig. 7 is a flowchart showing the steps of an injection valve operation process of the second embodiment embodying the present disclosure.

Fig. 8 is a flowchart showing the steps of an injection valve operation process of the third embodiment embodying the present disclosure.

Fig. 9 is a diagram showing a control device and an internal combustion engine according to a fourth embodiment embodying the present disclosure.

Fig. 10 is a block diagram showing a process executed by the control device in addition to the internal combustion engine of fig. 9.

Parts (a) and (b) of fig. 11 are timing charts showing injection patterns in the internal combustion engine of fig. 9.

Fig. 12 is a flowchart showing the steps of an injection valve operation process on the basis of the internal combustion engine of fig. 9.

Fig. 13 is a diagram showing a relationship between the catalyst temperature and the HC purification rate in the internal combustion engine of fig. 9.

Fig. 14A is a diagram showing the relationship between the end timing and the PN discharge amount in the internal combustion engine of fig. 9.

Fig. 14B is a diagram showing the relationship between the end timing and the amount of HC discharged in addition to the internal combustion engine shown in fig. 9.

Fig. 15 is a flowchart showing the steps of an injection valve operation process of a fifth embodiment of the present disclosure.

Detailed Description

< first embodiment >

Hereinafter, a control device for an internal combustion engine according to a first embodiment embodying the present disclosure will be described with reference to fig. 1 to 5.

An 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 upstream. The air taken into the intake passage 12 and the fuel injected from the port injection valve 16 flow into a combustion chamber 24 defined by the cylinder 20 and the piston 22 as the intake valve 18 opens. In the combustion chamber 24, a mixture of fuel and air is supplied to combustion by spark discharge of the ignition device 26. Combustion energy generated by the combustion is converted into rotational energy of the crankshaft 28 via the pistons 22. The mixed gas supplied after combustion is discharged as exhaust gas to the exhaust passage 32 as 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 an intake camshaft 40 and an exhaust camshaft 42 via the timing chain 38. In the present embodiment, the power of the timing chain 38 is transmitted to the intake camshaft 40 via the intake valve timing adjusting device 44. The intake 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 camshaft 40.

The control device 50 controls the internal combustion engine 10, and operates the operating portions of the internal combustion engine 10 such as the throttle valve 14, port injection valves 16, ignition device 26, and intake valve timing adjusting device 44 in order to control the control amount (torque, exhaust gas component ratio, and the like) of the internal combustion engine 10. At this time, the control device 50 refers to 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, the output signal Sca of the intake cam angle sensor 66, and the temperature of the cooling water (water temperature THW) of the internal combustion engine 10 detected by the water temperature sensor 68. Then, control device 50 refers to terminal voltage Vb of battery 70 detected by voltage sensor 72. Here, battery 70 is a power source for port injector 16 and the like. Fig. 1 shows operation signals MS1 to MS5 for operating the throttle valve 14, the port injection valve 16, the ignition device 26, the starter motor 36, and the intake valve timing adjusting device 44, respectively.

The control device 50 includes a CPU52, a ROM54, and a power supply circuit 56, and the CPU52 executes programs stored in the ROM 54. Therefore, the control of the above-described control amount is performed. The power supply circuit 56 supplies power to each part in the control device 50.

Fig. 2 shows a part of the processing performed by the control device 50. The process shown in fig. 2 is realized by the CPU52 executing a program stored in the ROM 54.

The intake phase difference calculation process M10 is a process of calculating an intake phase difference DIN, which is the phase difference between the rotation angle of the intake camshaft 40 with respect to the rotation angle of the crankshaft 28, based on the output signal Scr of the crank angle sensor 60 and the output signal Sca of the intake cam angle sensor 66. The target intake air phase difference calculation process M12 is a process of variably setting the target intake air phase difference DIN based on the operating point of the internal combustion engine 10. In the present embodiment, the operating point is defined by the rotation speed NE and the charging efficiency η. Here, the CPU52 calculates the rotation speed NE based on the output signal Scr of the crank angle sensor 60, and calculates the charging efficiency η based on the rotation speed NE and the intake air amount Ga. The filling efficiency η is a parameter for determining the amount of fresh air to be filled into the combustion chamber 24.

The intake phase difference control process M14 is a process of operating the intake valve timing adjusting device 44 to control the intake phase difference DIN to the target intake phase difference DIN, and for this purpose, outputting an operation signal MS5 to the intake valve timing adjusting device 44.

The base injection amount calculation process M20 is a process of calculating the base injection amount Qb based on the charging efficiency η. The basic injection amount Qb is a basic value of the amount of fuel for setting the air-fuel ratio of the mixture gas in the combustion chamber 24 to the target air-fuel ratio. Specifically, the basic injection amount calculation process M20 may be a process of calculating the basic injection amount Qb by multiplying the filling efficiency η by the fuel amount QTH per 1% of the filling efficiency η for setting the air-fuel ratio to the target air-fuel ratio when the filling efficiency η is expressed by a percentage, for example. The base injection amount Qb is an amount of fuel calculated to control the air-fuel ratio to the target air-fuel ratio based on the amount of fresh air charged into the combustion chamber 24. The target air-fuel ratio may be, for example, a stoichiometric air-fuel ratio.

The feedback process M22 is a process of calculating and outputting a feedback correction coefficient KAF obtained by adding "1" to the correction ratio δ of the base injection amount Qb. The correction ratio δ of the base injection amount Qb is a feedback operation amount that is an operation amount for feedback-controlling the air-fuel ratio Af to the target value Af. Specifically, the feedback process M22 sets, as the correction ratio δ, the sum of the output values of the proportional element and the derivative element, which are input with the difference between the air-fuel ratio Af and the target value Af, and the output value of the integral element, which is output while holding the integrated value of the value corresponding to the difference between the air-fuel ratio Af and the target value Af.

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 ℃). Specifically, when the water temperature THW is low, the low temperature increase coefficient Kw is calculated to be a larger value than when the water temperature THW 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 for the basic injection amount Qb based on the low temperature increase coefficient Kw is set to zero.

Injection valve operation process M30 is a process of outputting operation signal MS2 to port injection valve 16 in order to operate port injection valve 16. In particular, the injection valve operation process M30 is a process of outputting the operation signal MS2 to the port injection valve 16 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 airflow meter 62 is within the allowable range. Specifically, the process is a process of injecting the requested injection amount Qd, which is the amount of fuel requested to be supplied from the port injection valve 16 to one cylinder in 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 processes, i.e., the process illustrated in fig. 3 (a) and the process illustrated in fig. 3 (b).

Part (a) of fig. 3 is a multi-injection process for executing two fuel injections, i.e., an intake-synchronized injection for injecting fuel in synchronization with the valve-open period of the intake valve 18 and an intake-asynchronous injection for injecting fuel at a timing at an advanced angle side from the intake-synchronized injection. Specifically, the intake-synchronized injection injects the fuel such 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 converges to the valve-open period of the intake valve 18. Here, the "position before the opening of the intake valve 18" refers to the downstream end of the intake port, IN other words, the portion of the inlet IN to the combustion chamber 24 shown IN fig. 1. Fig. 1 shows a state in which the intake valve 18 is opened. The start point of the "reached period" is the timing at which the fuel injected at the earliest timing among the fuels injected from the port injection valves 16 reaches the position before the intake valves 18 open, and the end point of the "reached period" is the timing at which the fuel injected at the latest timing among the fuels injected from the port injection valves 16 reaches the position before the intake valves 18 open. In contrast, the "intake-non-synchronous injection" injects the fuel injected from the port injection valve 16 so that the fuel reaches the intake valve 18 before the intake valve 18 opens. In other words, "intake-non-synchronous injection" is injection in which the fuel injected from the port injection valve 16 is accumulated in the intake passage 12 before the intake valve 18 is opened, and flows into the combustion chamber 24 after the intake valve 18 is opened. In the present embodiment, the intake non-synchronous injection injects the fuel such 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 converges to the closing period of the intake valve 18.

Part (b) of fig. 3 is a single injection process in which only the intake-non-synchronized injection is performed.

In the present embodiment, the multiple injection process is performed to reduce the number (PN) of Particulate Matter (PM) in the exhaust gas. That is, when the temperature of the intake system of the internal combustion engine 10, such as the intake passage 12 or the intake valve 18, is low to some extent, PN tends to increase if the single injection process is executed in a range in which the charging efficiency η is large to some extent. The reason for this is considered to be that the required injection amount Qd is a larger value when the charging efficiency η is large than when the charging efficiency η is small, and as a result, the amount of fuel adhering to the intake system increases. Specifically, it is presumed that when the amount of fuel adhering to the intake system is large to a certain extent, part of the adhering fuel due to shearing of the adhering fuel directly flows into the combustion chamber 24 in the form of droplets. Therefore, in the present embodiment, a part of the required injection amount Qd is injected by the intake-synchronized injection. Therefore, even when the required injection amount Qd is large, the amount of fuel adhering to the intake system is reduced to a level higher than the required injection amount Qd, and PN is reduced. Note that, at the time of cold start of the internal combustion engine 10, the injection amount increases regardless of the charging efficiency η, and therefore PN tends to increase even when the single injection process is executed.

The steps of the process of the injection valve operation process M30 are shown in fig. 4. The process shown in fig. 4 is realized by the CPU52 repeatedly executing a program stored in the ROM54 at a predetermined cycle, for example. In the following, the step numbers of the respective processes are represented by numerals with "S" attached to the head.

In the series of processing shown in fig. 4, the CPU52 first determines whether or not the starter motor 36 is started (in the figure, after the starter is turned on) within a predetermined period (S10). Here, the "predetermined period" is a period in which the amount of air filled in the combustion chamber 24 cannot be accurately grasped and the base injection amount Qb cannot be accurately calculated. If the CPU52 determines that the start motor 36 is started within the predetermined period (yes in S10), it determines whether there is a request for the multi-injection process (S12). Here, the CPU52 determines that the multi-injection process is requested when the water temperature THW is less than the predetermined temperature Tth. When it is determined that the multi-injection process is requested (yes in S12), the CPU52 calculates an asynchronous injection quantity Qns, which is an injection quantity of intake asynchronous injection, based on the water temperature THW, the number of injections after the starter is turned on, and the stop time Tstp of the internal combustion engine 10 (S14). The stop time Tstp of the internal combustion engine 10 is an elapsed time from the last stop of the internal combustion engine 10 to the present start. Here, the CPU52 calculates the asynchronous injection amount Qns to be a larger value when the water temperature THW is low than when the water temperature THW is high. When the stop time Tstp is long, the CPU52 calculates the asynchronous injection amount Qns as a larger value than when the stop time Tstp is short.

Next, the CPU52 calculates a synchronous injection quantity Qs, which is an injection quantity of the intake synchronous injection, based on the water temperature THW (S16). Here, the CPU52 calculates the synchronous injection amount Qs as a larger value when the water temperature THW is low than when the water temperature THW is high.

The sum of the asynchronous injection amount Qns and the synchronous injection amount Qs is a required injection amount Qd that is an injection amount required for one combustion cycle. That is, the processing of S14, S16 is regarded as processing of allocating the fuel of the required injection amount Qd to the asynchronous injection amount Qns and the synchronous injection amount Qs.

Next, the CPU52 calculates an injection start timing Is (crank angle) of the intake-air-synchronized 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 temperature of the intake system of the internal combustion engine 10. Since the degree of vaporization of the fuel adhered to the intake system tends to vary depending on the water temperature THW, the injection start timing Is of the intake synchronous injection, which Is appropriate for suppressing PN, depends on the water temperature THW. Further, when the rotation speed NE is different, the flow velocity of the fluid in the intake passage 12 is different, and therefore the amount of fuel that does not flow into the combustion chamber 24 and adheres to the intake system and remains is different. When the rotation speed NE is different, the rotation amount of the crankshaft 28 is different in a period until a predetermined amount of fuel in the fuel injected from the port injection valves 16 is vaporized. Therefore, the injection start timing Is of the intake-synchronized injection, which Is appropriate in terms of suppressing PN, depends on the rotation speed NE. When the intake phase difference DIN is different, the overlap amount of the open period of the intake valve 18 and the open period of the exhaust valve 30 is different, and the blowback amount of the fluid from the combustion chamber 24 to the intake passage 12 is different. Further, since the temperature of the intake system varies depending on the blowback amount, the degree of vaporization of the fuel in the intake system varies, or the amount of fuel that remains attached to the intake system without flowing into the combustion chamber 24 varies. Therefore, the injection start timing Is of the intake-synchronized injection that Is appropriate in terms of suppressing PN depends on the intake phase difference DIN. Note that, even in a predetermined period after the starter is turned on, the target intake phase difference DIN cannot be changed based on the charging efficiency η, and therefore the target intake phase difference DIN can be made a fixed value. Even in this case, since the position where the target intake phase difference DIN Is fixed may vary from vehicle to vehicle, the injection start timing Is of the intake-synchronized injection Is calculated based on the intake phase difference DIN. Therefore, the versatility of the processing of S18 can be improved.

Specifically, the CPU52 performs a mapping operation on the injection start timing Is of the intake-synchronized injection in a state where mapping data having the water temperature THW, the rotation speed NE, and the intake phase difference DIN as input variables and having the injection start timing Is of the intake-synchronized injection as an output variable Is stored in the ROM54 in advance. Here, the "mapping data" refers to group data of the value of the dispersion of the input variable and the value of the output variable corresponding to the value of the input variable. The "mapping operation" may be any processing as long as, for example, when the value of the input variable matches any one of the values of the input variables of the mapping data, the value of the corresponding output variable of the mapping data is set as the operation result, and when the values of the input variables do not match any one of the values of the plurality of output variables included in the mapping data, the value obtained by interpolation is set as the operation result.

Next, the CPU52 calculates the injection start timing Ins (crank angle) of the intake-non-synchronous injection (S20). Here, the CPU52 calculates the injection start timing Ins of the intake-non-synchronous injection so that the time interval between the injection end timing of the intake-non-synchronous injection and the injection start timing Is of the intake-synchronous injection Is equal to or longer than a predetermined time. Here, the "predetermined time" is determined according to the structure of the port injection valve 16, and is a time for avoiding the start of the injection on the retarded angle side before the end of the injection on the advanced angle side in two fuel injections adjacent in time series. Then, the CPU52 operates the port injection valve 16 by outputting the operation signal MS2 to the port injection valve 16 in order to inject the fuel of the asynchronous injection quantity Qns at the injection start timing Ins, and then operates the port injection valve 16 by outputting the operation signal MS2 to the port injection valve 16 in order to inject the fuel of the synchronous injection quantity Qs at the injection start timing Is of the intake synchronous injection (S22).

On the other hand, if the CPU52 determines that there is no request for execution of the multi-injection process (no in S12), it calculates a required injection amount Qd, which is an injection amount required for one combustion cycle, based on the water temperature THW, the number of injections after the starter is turned on, and the stop time Tstp (S24). Next, the CPU52 sets the injection start timing Isin (crank angle) of the single injection (S26). Then, the CPU52 operates the port injection valves 16 by outputting the operation signal MS2 to the port injection valves 16 in order to inject the fuel of the required injection quantity Qd at the injection start timing Isin of the single injection (S22).

When the process of S22 is completed or when a negative determination is made in the process of S10, the CPU52 once ends the series of processes shown in fig. 4.

The steps of the process of the injection valve operation process M30 are shown in fig. 5. The process shown in fig. 5 is realized by the CPU52 repeatedly executing a program stored in the ROM54 at a predetermined cycle, for example.

In the series of processing shown in fig. 5, the CPU52 first determines whether or not a predetermined period of time has elapsed after the starter motor 36 is turned on (S30). When the CPU52 determines that the predetermined period has elapsed after the starter motor 36 is turned on (yes in S30), it determines whether or not there is a multi-injection request (S32). Here, the CPU52 determines that there is a request for execution of the multi-injection process when the logical product of the condition (i) that the water temperature THW is equal to or less than the predetermined temperature Tth, the condition (ii) that the filling efficiency η is equal to or more than the predetermined value, and the condition (iii) that the rotation speed NE is equal to or less than the predetermined speed NEth is true. The condition (iii) is a condition for ensuring a time interval between the end timing of the intake-non-synchronous injection and the start timing of the intake-synchronous injection. In addition, this condition is a condition that suppresses an excessive heat generation amount due to an increase in the calculation load of the control device 50 because the calculation load is larger in the multi-injection process than in the single-injection process.

When the CPU52 determines that there is a multi-injection request (S32: yes), it calculates a synchronous injection quantity Qs, which is the injection quantity of the intake synchronous injection (S34). Here, the CPU52 calculates the synchronous injection amount Qs from the rotation speed NE, the charging efficiency η, the water temperature THW, and the intake phase difference DIN. Specifically, the map data having the rotation speed NE, the charging efficiency η, the water temperature THW, and the intake phase difference DIN as input variables and the synchronous injection amount Qs as an output variable is stored in the ROM54 in advance, and the CPU52 performs the map operation on the synchronous injection amount Qs.

Next, the CPU52 calculates the asynchronous injection quantity Qns, which is the injection quantity of the intake-asynchronous injection, by subtracting the synchronous injection quantity Qs from the required injection quantity Qd, which is "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, the fuel of the required injection amount Qd is distributed into the asynchronous injection amount Qns and the synchronous injection amount Qs by the processing of S34 to S36. In addition, the synchronous injection amount Qs is not affected by the values of the feedback correction coefficient KAF and the low temperature increase coefficient Kw. The reason why the synchronous injection amount Qs is fixed in this way is because the change in the exhaust gas component ratio when the synchronous injection amount Qs is changed is more significant than the change in the exhaust gas component ratio when the asynchronous injection amount Qns is changed.

Next, the CPU52 calculates the end-of-arrival timing AEs shown IN part (a) of fig. 3, which is the target value of the timing at which the fuel injected at the latest timing among the fuels injected from the port injection valves 16 reaches the position (IN part of fig. 1) during the closing period of the intake valve 18, based on the rotation speed NE and the charging efficiency η (S38). Here, since the change in the flow velocity of the fluid in the intake passage 12 occurs when the rotation speed NE is different, the amount of fuel that does not flow into the combustion chamber 24 and adheres to the intake system and remains differs. When the rotation speeds NE are different, the amount of rotation of the crankshaft 28 during a period required for vaporization of a predetermined amount of the fuel injected from the port injection valves 16 is different. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the rotation speed NE. When the charging efficiency η differs, the base injection amount Qb differs, and the amount of fuel adhering to the intake system differs. When the charging efficiency η differs, the pressure in the intake passage 12 changes, and the fuel is atomized more easily. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the charging efficiency η.

Next, the CPU52 substitutes the arrival end timing AEs calculated in the process of S38 by a value obtained by multiplying the arrival end timing AEs by a water temperature correction coefficient Kthw which is a correction coefficient corresponding to the water temperature THW into the arrival end timing AEs (S40).

Here, the crank angle as a reference is located on the retard side with respect to the position on the most retard side assumed to reach the end timing AEs. The end time AEs is set to a value that is greater toward the advance side with respect to the crank angle as the reference. The water temperature correction coefficient Kthw is a value larger than zero. Specifically, when the water temperature THW is low, the CPU52 calculates the water temperature correction coefficient Kthw to a smaller value than when the water temperature THW is high, thereby correcting the arrival end timing AEs to the retard side. 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 THW is high, and therefore the amount of fuel that does not flow into the combustion chamber 24 and adheres to the intake system and remains increases, and therefore the timing appropriate for suppressing PN is shifted to the retard side.

Then, the CPU52 calculates an injection start timing Is of the intake-air-synchronized injection based on the arrival end timing AEs, the synchronized injection amount Qs, the rotation speed NE, and the terminal voltage Vb obtained by the processing of S40 (S42). Here, when the synchronous injection amount Qs Is large, the CPU52 calculates the injection start timing Is of the intake synchronous injection to a value more advanced than when the synchronous injection amount Qs Is small. When the rotation speed NE Is high, the CPU52 sets the injection start timing Is of the intake-synchronized injection to a value more advanced than when the rotation speed NE Is low. Specifically, the CPU52 sets the injection start timing Is of the intake-synchronized injection to a timing advanced from the end-reaching timing AEs by a value obtained by adding the injection period based on the port injection valve 16, the flight time, and the invalid injection time determined from the synchronized injection quantity Qs. Here, the "flight time" is a time required for the fuel injected from the port injection valve 16 to reach the inlet IN of the combustion chamber 24, and is a fixed value IN the present embodiment. The "invalid injection time" is a time until the injection of the fuel is actually started after the operation signal MS2 for opening the port injection valve 16 is output. Since the invalid injection time depends on the drive voltage applied to the port injection valve 16, the CPU52 calculates the invalid injection time from the terminal voltage Vb in the present embodiment.

Next, the CPU52 calculates the injection start timing Ins of the non-synchronous injection based on the injection start timing Is of the intake-air synchronous injection (S44). Here, the time interval between the injection end timing of the intake-non-synchronous injection and the injection start timing Is of the intake-synchronous injection Is equal to or longer than the predetermined time.

Through the above-described processing, the injection start timing Is of the intake-synchronized injection Is set independently of the injection start timing Ins of the intake-unsynchronized injection. The reason for this is because the above-described end-of-arrival timing AEs of intake-synchronized injection particularly easily affects PN and HC in exhaust gas.

Then, the CPU52 operates the port injection valves 16 by outputting the operation signal MS2 to the port injection valves 16 in order to inject the fuel of the non-synchronous injection quantity Qns at the injection start timing Ins and then inject the fuel of the synchronous injection quantity Qs at the injection start timing Is of the intake-synchronous injection (S46).

On the other hand, if the CPU52 determines that there is no request for the multi-injection process (S32: no), the CPU substitutes "KAF · Kw · Qb" for the requested injection amount Qd (S48). Next, the CPU52 calculates the injection start timing Isin of the single injection (S50). Specifically, as shown in part (b) of fig. 3, the CPU52 sets the arrival end timing ains as the timing advanced by a predetermined amount Δ 1 with respect to the opening start timing of the intake valve 18. Next, the CPU52 sets the injection start timing Isin of the single injection to a timing advanced with respect to the arrival end timing AEs by a value obtained by adding the injection period based on the port injection valve 16, the flight time, and the invalid injection time determined according to the required injection amount Qd. Returning to fig. 5, the CPU52 operates the port injection valves 16 by outputting the operation signal MS2 to the port injection valves 16 in order to inject the fuel of the required injection quantity Qd at the injection start timing Isin of the single injection (S46).

When the process of S46 is completed or when a negative determination is made in S30, the CPU52 once ends the series of processes shown in fig. 5.

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

The CPU52 variably sets the injection start timing Is of the intake-synchronized injection based on the water temperature THW, the rotation speed NE, and the intake phase difference DIN during a predetermined period after the starter Is turned on. After a predetermined period of time has elapsed after the starter Is turned on, the CPU52 variably sets the injection start timing Is of the intake-synchronized injection based on the rotation speed NE, the charging efficiency η, and the water temperature THW. Therefore, as compared with the case where the injection start timing Is of the intake-synchronized injection Is fixed, for example, the timing that Is optimal in terms of suppressing PN can be met, so PN can be suppressed.

According to the present embodiment described above, the following effects are also obtained.

(1) The CPU52 sets an injection start timing Is of the intake-synchronized injection based on the arrival-at-end timing AEs when a predetermined period elapses after the starter Is turned on. Here, it is found by the inventors that the appropriate timing IN terms of suppressing PN is determined by the timing at which the fuel injected from the port injection valve 16 reaches the inlet IN of the combustion chamber 24 at the latest timing. Further, the injection start timing Is of the intake-synchronized injection Is not uniquely determined from the timing at which the intake port IN Is reached, and the injection start timing Is of the intake-synchronized injection depends on the synchronized injection amount Qs and the like. Here, the synchronous injection amount Qs is calculated from the rotation speed NE, the water temperature THW, the charging efficiency η, and the intake phase difference DIN. Therefore, if the injection start timing Is of the intake-synchronized injection Is calculated without calculating the arrival end timing AEs, high-dimensional matching including at least all the parameters used for calculating the synchronized injection amount Qs Is required, and the number of matching steps increases. In contrast, in the present embodiment, the end-of-arrival timing AEs is used. Therefore, the matching between the two-dimensional parameters such as the rotation speed NE and the charging efficiency η and the arrival end timing AEs and the matching between the one-dimensional parameter such as the water temperature THW and the water temperature correction coefficient Kthw are sufficient, and therefore the matching man-hours can be reduced in the present embodiment.

< second embodiment >

The second embodiment will be described below mainly focusing on differences from the first embodiment with reference to fig. 6A to 7.

Fig. 6A and 6B each show the relationship between the end timing of arrival 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 becomes larger than zero by advancing the opening start timing of the intake valve 18.

As shown in fig. 6A and 6B, when the intake valve 18 is advanced and the overlap amount is increased, the best arrival end timing shifts to the advanced side in terms of PN suppression. The reason for this is considered to be that the fluid in the combustion chamber 24 is blown back into the intake passage 12 while both the intake valve 18 and the exhaust valve 30 are open, thereby raising the temperature of the intake system and facilitating vaporization of the fuel in the intake system. The amount of fuel that adheres to the intake system and remains without flowing into the combustion chamber 24 is considered to be reduced.

Therefore, in the present embodiment, the arrival end timing AEs is not directly matched, but the retard amount Δ AEs of the arrival end timing AEs with respect to the opening start timing of the intake valve 18 is matched. Therefore, the intake phase difference DIN is on the advance side, and the end timing AEs is on the advance side.

Fig. 6A shows the case where the water temperature THW is 0 °, 20 °, and 40 °, respectively, and fig. 6B shows the case where the water temperature THW is 0 °, and 20 °, respectively. Fig. 6A and 6B show that when the water temperature THW is low, PN can be suppressed even more by setting the arrival end timing AEs to the retarded side, and this tendency coincides with the setting of the water temperature correction coefficient Kthw in the processing of S40 in fig. 5.

Fig. 7 shows the procedure of the injection valve operation process M30 according to the present embodiment. The process shown in fig. 7 is realized by the CPU52 repeatedly executing a program stored in the ROM54 at a predetermined cycle, for example. 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 processing shown in fig. 7, after the processing of S36 is completed, the CPU52 calculates the hysteresis angle amount Δ AEs based on the rotation speed NE and the charging efficiency η (S38 a). Next, the CPU52 substitutes the value obtained by multiplying the water temperature correction coefficient Kthw by the retardation angle amount Δ AEs calculated in S38a for the retardation angle amount Δ AEs (S40 a). The arrival end timing AEs Is a timing retarded by the retard angle amount Δ AEs from the opening start timing of the intake valve 18 determined based on the intake phase difference DIN, and the CPU52 sets the injection start timing Is of the intake synchronous injection advanced from the arrival end timing AEs by a value obtained by adding the injection period based on the port injection valve 16 determined based on the synchronous injection amount Qs, the flight time, and the invalid injection time (S42 a). Then, the CPU52 shifts to the process of S44.

As described above, according to the present embodiment, since the reaching end timing AEs is determined by the retard angle amount Δ AEs, the valve opening start timing of the intake valve 18 is set to the advanced side and the reaching end timing AEs is set to the advanced side. This processing reflects the tendency shown in fig. 6A and 6B.

When the intake phase difference DIN is determined based on the rotation speed NE and the charging efficiency η, for example, the end-of-arrival timing AEs is determined based on the rotation speed NE and the charging efficiency η as in the first embodiment. Therefore, the more the intake phase difference DIN is on the advance angle side, the more the end-to-end timing AEs conforms to the value on the advance angle side. However, even with the same internal combustion engine 10, the setting of the intake phase difference DIN corresponding to the rotation speed NE and the charging efficiency η may differ depending on the type of vehicle mounted, and restarting matching to the end timing AEs only by changing the setting reason in this case may increase the number of matching steps. In contrast, in the present embodiment, the hysteresis angle amount Δ AEs is matched. Therefore, even in the case where the settings of the intake phase difference DIN corresponding to the rotation speed NE and the charging efficiency η are different, the retardation angle amount Δ AEs can be shared between those cases where the settings of the intake phase difference DIN are different from each other.

< third embodiment >

The third embodiment will be described below mainly focusing on differences from the first embodiment with reference to fig. 8.

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 CPU52 repeatedly executing a program stored in the ROM54 at predetermined cycles, for example. In fig. 8, the same step numbers are assigned to the processes corresponding to the process shown in fig. 5 for convenience.

In the series of processes shown in fig. 8, the CPU52 selectively executes any one of the following processes (S38b) according to the value of the water temperature THW (shown as THW1, … THWn in the drawing) when the process of S36 is completed. Here, the first processing is processing of performing a map operation on the arrival end timing AEs based on map data having the rotation speed NE, the charging efficiency η, and the intake phase difference DIN as input variables and having the arrival end timing AEs as an output variable. The second processing is processing for performing a map operation on the hysteresis angle Δ AEs with map data in which the rotation speed NE and the charging efficiency η are input variables and the hysteresis angle Δ AEs is output variable. Here, the first process advances the arrival end timing AEs in proportion to the advance angle amount of the opening start timing of the intake valve 18, and is executed in a water temperature range in which there is a fear that the arrival end timing AEs may not be optimal in terms of PN suppression.

Next, the CPU52 executes the process of S42a in fig. 7 or the process corresponding to S42 in fig. 5 depending on whether the retard angle amount Δ AEs or the arrival end timing AEs was calculated in the process of S38b (S42 b). Note that the CPU52 proceeds to the process of S44 when the process of S42b is completed.

As described above, in the present embodiment, the arrival end timing AEs is determined in proportion to the advance angle amount of the opening start timing of the intake valve 18, and thus the coincidence value of the arrival end timing AEs corresponding to the rotation speed NE, the charging efficiency η, and the intake phase difference DIN is used in a water temperature range that is difficult to optimize from the viewpoint of PN suppression. Therefore, the PN can be further reduced while suppressing an increase in the number of fitting man-hours. Also, the end-of-arrival timing AEs is set based on the intake phase difference DIN. Therefore, for example, when the water temperature THW is low, the intake air phase difference DIN can be set to a value suitable for suppressing PN even when the intake air phase difference DIN is not set to a value corresponding to the rotation speed NE and the charging efficiency η, but is set to a value on the more retarded side.

< correspondence relationship >

The correspondence between the items in the above embodiment and the items described in the above "summary of the invention" is as follows. The correspondence relationship is shown below by the number of the example described in the column "summary of the invention".

[1] "multi-ejection processing" corresponds to the processing of S22 after the processing of S20 in fig. 4 and the processing of S46 after the processing of S44 in fig. 5.

The "variable processing" corresponds to 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 S42b in fig. 8, respectively.

[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 base injection amount Qb, the feedback correction coefficient KAF, and the low temperature increase coefficient Kw are calculated by the above-described respective processes, and the required injection amount Qd is considered to be calculated.

[3] The "end timing setting processing" of "5" and "6" correspond to the processing of S38 and S40 in fig. 5, the processing of S38a and S40a in fig. 7, and the processing of S38b in fig. 8, respectively. That is, the arrival end timing is the timing delayed by the retard angle amount Δ AEs from the opening start timing of the intake valve 18 determined based on the intake phase difference DIN. Therefore, the case where the intake phase difference DIN is referred to in the processing of S42a and S42b is regarded as a timing delayed by the retard angle amount Δ AEs from the opening start timing of the intake valve 18.

The "start timing calculation process" corresponds to the process of S42 in fig. 5, the process of S42a in fig. 7, and the process of S42b in fig. 8, respectively.

[4] "valve characteristic varying device" of [7] corresponds to the intake valve timing adjusting device 44, and "valve characteristic control processing" corresponds to the target intake phase difference calculating processing M12 and the intake phase difference control processing M14. The "lag angle amount calculation process" corresponds to the processes of S38a and S38 b.

< other embodiment >

The above embodiments may be modified and implemented as follows. The above embodiments and the following modifications can be combined and implemented within a range not technically contradictory to each other.

"processing for calculation of start timing"

In the above-described embodiment, the injection start timing Is of the intake-air-synchronized injection 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 thereto. For example, the invalid injection time may be set to a fixed value.

"processing for calculating end timing"

In fig. 7, the hysteresis angle amount Δ AEs is mapped using the map data in which the rotation speed NE and the charging efficiency η are input variables and the hysteresis angle amount Δ AEs is output variable, and the hysteresis angle amount Δ AEs is corrected based on the water temperature THW, but the present invention is not limited thereto. For example, the map calculation may be performed using map data in which the rotation speed NE, the charging efficiency η, and the water temperature THW are input variables and the hysteresis angle Δ AEs is an output variable.

In fig. 8, the end-of-arrival timing AEs is mapped using the map data having the rotation speed NE, the charging efficiency η, and the intake phase difference DIN as input variables and the end-of-arrival timing AEs as output variables only when the water temperature THW enters the predetermined temperature range, but the present invention is not limited to this. For example, the end-of-arrival timing AEs may be subjected to the map operation using map data having the rotation speed NE, the charging efficiency η, and the intake phase difference DIN as input variables and the end-of-arrival timing AEs as output variables, regardless of the water temperature THW, and the end-of-arrival timing AEs may be corrected based on the water temperature THW. Instead, the end-of-arrival timing AEs may be mapped using map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and having the end-of-arrival timing AEs as an output variable.

"about variable processing"

(a) Within a predetermined period after the starter is turned on

In fig. 4, the injection start timing is mapped based on the map data having the rotation speed NE, the water temperature THW, and the intake phase difference DIN as input variables and the injection start timing as an output variable, but the present invention is not limited thereto. For example, the injection start timing may be corrected based on the water temperature THW by performing a map operation on the injection start timing based on map data having the rotation speed NE and the intake phase difference DIN as input variables and the injection start timing as an output variable. For example, the injection start timing may be calculated based on only the rotation speed NE and the water temperature THW regardless of the intake phase difference DIN, based on the rotation speed NE and the intake phase difference DIN regardless of the water temperature THW, or 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 of time has elapsed after the starter is turned on

In the above embodiment, the end-of-arrival timing AEs is set based on the rotation speed NE, the charging efficiency η, the water temperature THW, and the like, but is not limited thereto. As the parameter (parameter indicating the load) indicating the amount of fresh air to be charged into the combustion chamber 24, for example, the basic injection amount Qb may be used instead of the charging efficiency η. In addition to the above-described embodiments, the end-of-arrival timing AEs may be variably set based on only three of the four parameters, i.e., the rotation speed NE, the load, the water temperature THW, and the intake air phase difference DIN, or may be variably set based on only two of the three parameters.

The injection start timing Is of the intake-synchronized injection Is calculated after the end timing AEs and the retard amount Δ AEs are calculated. For example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data having the rotation speed NE and the charging efficiency η as input variables and the injection start timing Is of the intake-synchronized injection as an output variable. In this case, the calculated injection start timing Is of the intake-air-synchronized injection may be corrected in accordance with the water temperature THW. Further, for example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data having the rotation speed NE, the charging efficiency η, and the intake phase difference DIN as input variables and the injection start timing Is of the intake-synchronized injection as an output variable. In this case, the calculated injection start timing Is of the intake-air-synchronized injection may be corrected in accordance with the water temperature THW. Further, for example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and having the injection start timing Is of the intake-synchronized injection as 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 timing Is of the intake-synchronized injection may be corrected based on the terminal voltage Vb.

"temperature in relation to air intake System"

In the above configuration, the water temperature THW is used as the temperature of the intake system, but the present invention is not limited thereto. It is also possible to use, for example, the temperature of the lubricating oil of the internal combustion engine 10.

"regarding required injection quantity"

The required injection amount Qd may be a value obtained by correcting the basic injection amount Qb by the learning value LAF in addition to the low temperature increase coefficient Kw and the feedback correction coefficient KAF. The learning value LAF is calculated by inputting the feedback correction coefficient KAF and updating the learning value LAF so that the correction ratio of the basic injection amount Qb based on the feedback correction coefficient KAF is reduced. The learning value LAF is preferably stored in a nonvolatile memory that can be electrically rewritten.

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

"injection with asynchronous inlet"

In the above embodiment, the intake non-synchronous injection is performed such that the fuel injected from the port injection valve 16 converges to the closed period of the intake valve 18 while the period during which the fuel reaches the position before the opening of the intake valve 18 is reduced, but the present invention is not limited thereto. For example, when the rotation speed NE is high and the asynchronous injection amount Qns is excessive, 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 may overlap the opening period of the intake valve 18.

"about Single shot treatment"

In the above embodiment, the single injection process is performed such that the fuel injected from the port injection valve 16 is injected such that the period during which the fuel reaches the position before the opening of the intake valve 18 converges to the closing period of the intake valve 18, but the present invention is not limited thereto. 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 may overlap the opening period of the intake valve 18. It is noted that it is not necessary to perform a single injection process.

"method of dispensing required amount of spray"

In the above embodiment, the synchronous injection amount Qs is variably set based on the rotation speed NE, the charging efficiency η, the water temperature THW, and the intake phase difference DIN, but is not limited thereto. For example, the basic injection amount Qb may be used instead of the charging efficiency η as a load parameter that is a parameter indicating the amount of fresh air to be charged into the combustion chamber 24. Further, the synchronous injection amount Qs may be variably set based on only three of the load parameter, the rotation speed NE, the water temperature THW, and the intake phase difference DIN, or may be variably set based on only two of the parameters, or may be variably set based on only one of the parameters. In this case, it is preferable to variably set the synchronous injection amount Qs by using at least one of the load parameter and the water temperature THW as much as possible. Further, in addition to the above-described four parameters, for example, the intake pressure or the flow rate of the intake air may be used. However, from the above four parameters, the intake air pressure and the flow rate of the intake air can be grasped.

It is not essential to calculate the synchronous injection amount Qs, and 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 the load, for example. For example, the value "KAF · Qb" obtained by correcting the base injection amount Qb by the feedback correction coefficient KAF may be assigned to the synchronous injection amount Qs by using the synchronous injection ratio Ks. In this case, the synchronized injection amount Qs becomes "Ks · KAF · Qb".

"control process for valve characteristics"

In the above embodiment, the target intake phase difference DIN is variably set in accordance with the rotation speed NE and the charging efficiency η, but is not limited thereto. For example, as described in the third embodiment, when the water temperature THW is low, the actual timing may be exceptionally limited to the retarded side or the like with respect to the opening timing of the intake valve 18 determined according to the rotation speed NE and the charging efficiency η.

Devices relating to variation of characteristics of inlet valves "

The characteristic varying device for varying the characteristic of the intake valve 18 is not limited to the intake 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 characteristic of the intake valve 18 is changed to a lift amount or the like instead of the intake phase difference DIN.

"about control device"

The control device is not limited to being provided with the CPU52 and the ROM54 and executing software processing. For example, a dedicated hardware circuit (e.g., ASIC) may be provided for performing hardware processing on at least a part of the software-processed part in the above-described embodiment. That is, the control device may have any one of the following configurations (a) to (c). (a) The processing device includes a processing device that executes all of the above-described processing in accordance with a program, and a program storage device (including a non-transitory computer-readable recording medium) such as a ROM that stores the program. (b) The apparatus includes a processing device for executing a part of the above-described processing in accordance with a program, a program storage device, and a dedicated hardware circuit for executing the remaining processing. (c) The apparatus includes a dedicated hardware circuit for executing all of the above-described processing. Here, the number of the software processing circuits and dedicated hardware circuits provided with the processing device and the program storage device may be plural. That is, the above-described 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.

"other"

It is not essential that the internal combustion engine 10 be provided with a characteristic varying device that varies the characteristic of the intake valve 18. It is not essential that the internal combustion engine 10 be provided with the throttle valve 14.

In the case where the vehicle equipped with the internal combustion engine 10 is equipped with a rotating electrical machine as a prime mover for generating thrust of the vehicle, the rotating electrical machine may be used instead of the starter motor 36 as means for applying initial rotation to the crankshaft 28.

< fourth embodiment >

A control device for an internal combustion engine according to a fourth embodiment embodying the present disclosure will be described below with reference to fig. 9 to 14B.

An internal combustion engine 10 shown in fig. 9 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 upstream. The air taken into the intake passage 12 and the fuel injected from the port injection valve 16 flow into a combustion chamber 24 defined by the cylinder 20 and the piston 22 as the intake valve 18 opens. In the combustion chamber 24, a mixture of fuel and air is supplied to combustion by spark discharge of the ignition device 26. Combustion energy generated by the combustion is converted into rotational energy of the crankshaft 28 via the pistons 22. The mixed gas supplied to combustion is discharged as exhaust gas to the exhaust passage 32 as the exhaust valve 30 is opened. A catalyst 34 is provided in the exhaust passage 32. A filter (GPF136) that collects Particulate Matter (PM) in the exhaust gas is provided downstream of the catalyst 34 in the exhaust passage 32.

The control device 50 controls the internal combustion engine 10, and operates the operating portions of the internal combustion engine 10 such as the throttle valve 14, port injection valves 16, ignition device 26, and intake valve timing adjusting device 44 in order to control the control amount (torque, exhaust gas component ratio, and the like) of the internal combustion engine 10. At this time, the control device 50 refers to 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, the output signal Sca of the intake cam angle sensor 66, and the temperature of the cooling water (water temperature THW) of the internal combustion engine 10 detected by the water temperature sensor 68. Fig. 9 shows operation signals MS1 to MS3 and MS5 for operating the throttle valve 14, the port injection valve 16, the ignition device 26, and the intake valve timing adjusting device 44, respectively.

The control device 50 includes a CPU52, a ROM54, and a power supply circuit 56, and executes the control of the control amount by the CPU52 executing a program stored in the ROM 54. The power supply circuit 56 supplies power to each part in the control device 50.

Fig. 10 shows a part of the processing executed by the control device 50. The process shown in fig. 10 is realized by the CPU52 executing a program stored in the ROM 54.

The intake phase difference calculation process M10 is a process of calculating an intake phase difference DIN, which is the phase difference between the rotation angle of the intake camshaft 40 with respect to the rotation angle of the crankshaft 28, based on the output signal Scr of the crank angle sensor 60 and the output signal Sca of the intake cam angle sensor 66. The target intake air phase difference calculation process M12 is a process of variably setting the target intake air phase difference DIN based on the operating point of the internal combustion engine 10. In the present embodiment, the operating point is defined by the rotation speed NE and the charging efficiency η. Here, the CPU52 calculates the rotation speed NE based on the output signal Scr of the crank angle sensor 60, and calculates the charging efficiency η based on the rotation speed NE and the intake air amount Ga. The charging efficiency η is a parameter for determining the amount of air to be charged into the combustion chamber 24.

The basic injection amount calculation process M20 is a process of calculating a basic injection amount Qb that is a basic value of the amount of fuel for setting the air-fuel ratio of the air-fuel mixture in the combustion chamber 24 to the target air-fuel ratio, based on the charging efficiency η. Specifically, the basic injection amount calculation process M20 may be a process of calculating the basic injection amount Qb by multiplying the filling efficiency η by the fuel amount QTH per 1% of the filling efficiency η for setting the air-fuel ratio to the target air-fuel ratio when the filling efficiency η is expressed by a percentage, for example. The base injection amount Qb is an amount of fuel calculated to control the air-fuel ratio to the target air-fuel ratio based on the amount of air charged into the combustion chamber 24. The target air-fuel ratio may be, for example, a stoichiometric air-fuel ratio.

The feedback process M22 is a process of calculating and outputting a feedback correction coefficient KAF obtained by adding "1" to the correction ratio δ of the base injection amount Qb, which is the feedback manipulated variable. The correction ratio δ of the base injection amount Qb is an operation amount for feedback-controlling the air-fuel ratio Af to the target value Af. Specifically, the feedback process M22 sets, as the correction ratio δ, the sum of the output values of the proportional element and the derivative element, which are input with the difference between the air-fuel ratio Af and the target value Af, and the output value of the integral element, which is output while holding the integrated value of the value corresponding to the difference between the air-fuel ratio Af and the target value Af.

Injection valve operation process M30 is a process of outputting operation signal MS2 to port injection valve 16 in order to operate port injection valve 16. In particular, the injection valve operation process M30 is a process of causing the port injection valve 16 to inject the requested injection quantity Qd, which is the quantity of fuel requested to be supplied from the port injection valve 16 to one cylinder in one combustion cycle.

In the present embodiment, the fuel injection process includes two processes, i.e., the process illustrated in part (a) of fig. 11 and the process illustrated in part (b) of fig. 11.

Part (a) of fig. 11 is a multi-injection process for executing two fuel injections, i.e., an intake-synchronized injection for injecting fuel in synchronization with the valve-open period of the intake valve 18 and an intake-asynchronous injection for injecting fuel at a timing at an advanced angle side from the intake-synchronized injection. Specifically, the intake-synchronized injection injects the fuel such 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 converges to the valve-open period of the intake valve 18. Here, the "position before the opening of the intake valve 18" refers to the downstream end of the intake port, IN other words, the portion of the inlet IN to the combustion chamber 24 shown IN fig. 9. Fig. 9 shows a state in which the intake valve 18 is opened. The start point of the "arrival period" is the timing at which the fuel injected at the earliest timing among the fuels injected from the port injection valves 16 reaches the position before the intake valves 18 are opened. The end point of the "arrival period" is the timing at which the fuel injected at the latest timing among the fuels injected from the port injection valves 16 reaches the position before the intake valves 18 are opened. In contrast, the "intake-non-synchronous injection" injects the fuel injected from the port injection valve 16 so that the fuel reaches the intake valve 18 before the intake valve 18 opens. In other words, "intake-non-synchronous injection" is injection in which the fuel injected from the port injection valve 16 is accumulated in the intake passage 12 before the intake valve 18 is opened, and flows into the combustion chamber 24 after the intake valve 18 is opened. In the present embodiment, the intake non-synchronous injection injects the fuel such 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 converges to the closing period of the intake valve 18.

Part (b) of fig. 11 is a single injection process in which only the intake-non-synchronized injection is performed.

In the present embodiment, the multiple injection process is performed to reduce the number (PN) of Particulate Matter (PM) in the exhaust gas. That is, when the temperature of the intake system of the internal combustion engine 10, such as the intake passage 12 or the intake valve 18, is low to some extent, PN tends to increase if the single injection process is executed in a range in which the charging efficiency η is large to some extent. The reason for this is considered to be that the required injection amount Qd is a larger value when the charging efficiency η is large than when the charging efficiency η is small, and as a result, the amount of fuel adhering to the intake system increases. Specifically, it is presumed that when the amount of fuel adhering to the intake system is large to a certain extent, part of the adhering fuel due to shearing of the adhering fuel directly flows into the combustion chamber 24 in the form of droplets. Therefore, in the present embodiment, a part of the required injection amount Qd is injected by the intake-synchronized injection. Therefore, even when the required injection amount Qd is large, the amount of fuel adhering to the intake system is reduced to a level higher than the required injection amount Qd, and PN is reduced.

The steps of the process of the injection valve operation process M30 are shown in fig. 12. The process shown in fig. 12 is realized by the CPU52 repeatedly executing a program stored in the ROM54 at predetermined cycles, for example. In the following, the step numbers of the respective processes are represented by numerals with "S" attached to the head.

In the series of processes shown in fig. 12, the CPU52 first updates the value of the warm-up count C by the update amount Δ C (S110). The warm-up count C is a parameter having a correlation with the temperature of the catalyst 34. The CPU52 calculates the update amount Δ C as a larger value when the intake air amount Ga is large than when the intake air amount Ga is small. Here, when the intake air amount Ga is small, the update amount Δ C may be smaller than zero. Further, although the intake air amount Ga is the same, when the value of the warm-up count C is large, the CPU52 calculates the update amount Δ C to be a smaller value than when the value of the warm-up count C is small. This is because the temperature of the catalyst 34 becomes difficult to rise as the warm-up proceeds. This processing can be realized by the CPU52 performing a mapping operation on the update amount Δ C in a state where mapping data having the warm-up count C and the intake air amount Ga as input variables and the update amount Δ C as output variables is stored in the ROM54 in advance.

Here, the mapping data is group data of discrete values of the input variables and values of the output variables corresponding to the values of the input variables. The map operation may be a process in which, for example, when the value of the input variable matches any one of the values of the input variables of the map data, the value of the corresponding output variable of the map data is used as the operation result, whereas when the values do not match, the value obtained by interpolation of the values of the plurality of output variables included in the map data is used as the operation result.

Next, the CPU52 calculates the required injection amount Qd by multiplying the base injection amount Qb by the low temperature increase coefficient Kw and the feedback correction coefficient KAF (S112). Next, the CPU52 determines whether there is a multiple injection request (S114). Here, the CPU52 determines that there is a request for execution of the multi-injection process when the logical product of the condition (Vi) indicating that the water temperature THW is equal to or lower than the predetermined temperature Tth, the condition (Vii) indicating that the charging efficiency η is equal to or higher than the predetermined value, and the condition (Vii) indicating that the rotation speed NE is equal to or lower than the predetermined speed nth is true. The condition (Viii) is a condition for ensuring that the time interval between the end timing of the intake-non-synchronous injection and the start timing of the intake-synchronous injection is equal to or longer than a predetermined time. In addition, this condition is a condition for suppressing an excessive heat generation amount due to an increase in the calculation load of the control device 50 because the calculation load is larger in the multi-injection process than in the single-injection process. The "predetermined time" is determined according to the structure of the port injection valve 16, and is set to a value that can avoid the start of the intake-synchronized injection before the end of the intake-unsynchronized injection.

When the CPU52 determines that there is a multi-injection request (yes in S114), it calculates a synchronous injection quantity Qs, which is the injection quantity of the intake synchronous injection (S116). Here, the CPU52 calculates the synchronous injection quantity Qs from the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW. The synchronous injection amount Qs corresponds to a value appropriate in suppressing PN. Specifically, the map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and the synchronous injection amount Qs as an output variable is stored in the ROM54 in advance, and the CPU52 performs the map operation on the synchronous injection amount Qs.

Next, the CPU52 calculates the asynchronous injection amount Qns, which is the injection amount of the intake-air asynchronous injection, by subtracting the synchronous injection amount Qs from the required injection amount Qd (S118).

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, the fuel of the required injection amount Qd is distributed into the asynchronous injection amount Qns and the synchronous injection amount Qs by the processing of S116 and S118. In addition, the synchronous injection amount Qs is not affected by the values of the feedback correction coefficient KAF and the low temperature increase coefficient Kw. The reason why the synchronous injection amount Qs is fixed in this way is because the synchronous injection amount Qs corresponds to a value appropriate for suppressing PN, and therefore, if the synchronous injection amount Qs is largely changed by correction, PN may be increased.

Next, the CPU52 determines whether the warm-up count C is equal to or greater than a threshold Cth (S120). This process is a process for determining whether or not the temperature of the catalyst 34 is equal to or higher than a predetermined value for bringing the catalyst into an active state. The "active state" here is only required to be a temperature at which the purification rate becomes 50% or more, for example, at the center of the catalyst 34. Specifically, the CPU52 sets the threshold Cth to a smaller value when the water temperature THW is high than when the water temperature THW is low.

When the CPU52 determines that the warm-up count C is equal to or greater than the threshold Cth (S120: yes), the catalyst 34 is in the active state, and the arrival end timing AEs shown in part (a) of fig. 11 is calculated based on the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW (S122). The end time AEs is a target value of the timing at which the fuel injected at the latest timing among the fuels injected from the port injection valves 16 reaches the position (the inlet portion in fig. 9) in the closing period of the intake valve 18. Here, since the change in the flow velocity of the fluid in the intake passage 12 occurs when the rotation speed NE is different, the amount of fuel that does not flow into the combustion chamber 24 and adheres to the intake system and remains differs. When the rotation speed NE is different, the amount of rotation of the crankshaft 28 in the period required until a predetermined amount of fuel in the fuel injected from the port injection valves 16 vaporizes differs. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the rotation speed NE. When the charging efficiency η differs, the base injection amount Qb differs, and the amount of fuel adhering to the intake system differs. When the charging efficiency η differs, the pressure in the intake passage 12 changes, and the fuel is atomized more easily. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the charging efficiency η. Further, when the water temperature THW is low, the fuel in the intake system becomes less likely to vaporize than when the water temperature THW is high, and the amount of fuel that does not flow into the combustion chamber 24 and adheres to the intake system and remains increases, so the optimum timing is shifted to the retard side in order to suppress PN. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the water temperature THW. Further, since the internal EGR amount changes as the overlap amount of the intake valve 18 and the exhaust valve 30 changes according to the intake phase difference DIN, the degree of easiness of vaporization of the fuel in the intake system changes as the temperature of the intake system increases, or the amount of fuel that remains attached to the intake system without flowing into the combustion chamber 24 changes. Therefore, the arrival end timing AEs appropriate in suppressing PN depends on the intake phase difference DIN.

Specifically, in a state where map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and the arrival end timing AEsa at the time of catalyst activation as an output variable is stored in the ROM54 in advance, the arrival end timing AEsa is subjected to map operation by the CPU52 and is set as the arrival end timing AEs.

On the other hand, when the CPU52 determines that the warm-up count C is smaller than the threshold Cth (S120: no), the arrival end timing AEsb before the catalyst activation is calculated and set as the arrival end timing AEs (S124). Specifically, in a state where map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and the arrival end timing AEsb before the catalyst activation as an output variable is stored in the ROM54 in advance, the arrival end timing AEsb is subjected to a map operation by the CPU52 and is set as the arrival end timing AEs. The arrival end timing AEsb before the catalyst activation is a value advanced from the arrival end timing AEsa when the catalyst 34 is in the active state.

When the processing in S122 and S124 Is completed, the CPU52 calculates an injection start timing Is (crank angle) of the intake-air synchronized injection based on the arrival end timing AEs, the synchronized injection amount Qs, and the rotation speed NE (S126). Here, when the synchronous injection amount Qs Is large, the CPU52 calculates the injection start timing Is of the intake synchronous injection to a value more advanced than when the synchronous injection amount Qs Is small. When the rotation speed NE Is high, the CPU52 sets the injection start timing Is of the intake-synchronized injection to a value more advanced than when the rotation speed NE Is low. Specifically, the CPU52 sets the injection start timing Is of the intake-synchronized injection to a timing advanced from the end-reaching timing AEs by a value obtained by adding the injection period based on the port injection valve 16, the flight time, and the invalid injection time determined from the synchronized injection quantity Qs. Here, the "flight time" is a time required for the fuel injected from the port injection valve 16 to reach the inlet IN of the combustion chamber 24, and is a fixed value IN the present embodiment. The "invalid injection time" is a time until the injection of the fuel is actually started after the operation signal MS2 for opening the port injection valve 16 is output.

Next, the CPU52 calculates the injection start timing Ins of the intake-air non-synchronous injection based on the injection start timing Is of the intake-air synchronous injection (S128). Here, the time interval between the injection end timing of the intake-non-synchronous injection and the injection start timing Is of the intake-synchronous injection Is equal to or longer than the predetermined time.

Through the above-described processing, the injection start timing Is of the intake-synchronized injection Is set independently of the injection start timing Ins of the intake-unsynchronized injection. This is because the above-described end-of-arrival timing AEs of intake-synchronized injection particularly easily affects PN and HC in exhaust gas.

Then, the CPU52 operates the port injection valves 16 by outputting the operation signal MS2 to the port injection valves 16 in order to inject the fuel of the asynchronous injection quantity Qns when the injection start timing Ins becomes the injection start timing Ins and then inject the fuel of the synchronous injection quantity Qs when the injection start timing Is becomes the intake synchronous injection (S130).

On the other hand, if the CPU52 determines that there is no request for the multi-injection process (no in S114), it calculates the injection start timing Isin of the single injection (S132). Specifically, as shown in part (b) of fig. 11, the CPU52 sets the arrival end timing AEns to a timing advanced by a predetermined amount Δ 1 with respect to the opening start timing of the intake valve 18. Next, the CPU52 sets the injection start timing Isin of the single injection to a timing advanced from the arrival end timing AEns by a value obtained by adding the injection period based on the port injection valve 16, the flight time, and the invalid injection time determined according to the required injection amount Qd. Returning to fig. 12, the CPU52 operates the port injection valves 16 by outputting the operation signal MS2 to the port injection valves 16 in order to inject the fuel of the required injection quantity Qd at the injection start timing Isin that becomes the single injection (S130).

When the process of S130 is completed, the CPU52 once ends the series of processes shown in fig. 12.

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

When there is a request for execution of the multi-injection process, the CPU52 sets the end reaching timing AEs to a value more advanced than that when the warm-up count C is equal to or greater than the threshold Cth, for example, when the warm-up count C is smaller than the threshold Cth. This is because the HC purification rate is lower when the temperature of the catalyst 34 is low as shown in fig. 13 than when the temperature of the catalyst 34 is high, and on the other hand, the HC discharge is suppressed as the end timing AEs is located on the advance side as shown in fig. 14B.

Fig. 14A shows the relationship between the arrival end timings AEs, AEns and the concentration of PN in exhaust gas, and fig. 14B shows the relationship between the arrival end timings AEs, AEns and the concentration of HC in exhaust gas. Specifically, the values of PN and HC related to the arrival end timing AEs are values described as "at the time of multiple injection", and the values of PN and HC related to the arrival end timing AEns are values described as "at the time of single injection". The arrival end timing AEs that is optimal in suppressing PN shown by the vertical line of the solid line in both fig. 14A and 14B is a value closer to the advance side than the arrival end timing AEs that is appropriate in suppressing HC shown by the broken line in both fig. 14A and 14B. The reason for this is considered to be that the time margin for atomizing the fuel is more generated as the arrival end timing AEs becomes the advanced angle side value.

The CPU52 uses the appropriate end-of-arrival timing AEsb for HC suppression when the temperature of the catalyst 34 is low, thereby suppressing HC in the exhaust gas and further suppressing HC flowing out downstream of the catalyst 34. In this case, PM flowing downstream of the catalyst 34 is collected by the GPF 136. In contrast, the CPU52 uses the appropriate arrival end timing AEsa for suppressing PN when the temperature of the catalyst 34 becomes high, thereby suppressing PN in the exhaust gas. In this case, HC in the exhaust gas is sufficiently purified by the catalyst 34.

< fifth embodiment >

The fifth embodiment will be described below mainly focusing on differences from the fourth embodiment with reference to fig. 15.

The steps of the process of the injection valve operation process M30 are shown in fig. 15. The process shown in fig. 15 is realized by the CPU52 repeatedly executing programs stored in the ROM54 at predetermined cycles, for example. In fig. 15, the same step numbers are assigned to the processes corresponding to the process shown in fig. 12 for convenience.

After calculating the asynchronous injection amount Qns (S118), the CPU52 calculates the end-of-arrival timing AEs based on the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW (S122 a). The arrival end timing AEs here is a timing suitable for suppressing PN, and corresponds to the arrival end timing AEsa calculated in the process of S122. Next, the CPU52 determines whether the warm-up count C is equal to or greater than a threshold Cth (S120). When the CPU52 determines that the warm-up count C Is equal to or greater than the threshold Cth (S120: YES), it calculates the injection start timing Is of the intake-synchronized injection using the arrival end timing AEs calculated in the processing of S122a (S126).

On the other hand, when the CPU52 determines that the warm-up count C is smaller than the threshold Cth (S120: no), it calculates a delay protection value AEth of the end time AEs based on the water temperature THW and the rotation speed NE (S134). The retard guard value AEth is set according to the most retarded angle side angle in terms of bringing the HC concentration in the exhaust gas into the allowable range before the catalyst 34 is activated. Specifically, the delay angle protection value AEth is mapped by the CPU52 in a state where map data having the rotation speed NE and the water temperature THW as input variables and the delay angle protection value AEth as an output variable is stored in the ROM54 in advance.

Next, the CPU52 substitutes the arrival end timing AEs calculated in the processing of S122a and the advance side one of the retard guard values AEth for the arrival end timing AEs (S136). Specifically, the arrival end timing AEs is expressed by a relative angle with respect to the angle as the reference, and is set to a positive value on the advanced angle side with respect to the angle as the reference. The non-smaller value of the arrival end timing AEs and the retard guard value AEth is substituted for the arrival end timing AEs.

Then, the CPU52 calculates the injection start timing Is of the intake-synchronized injection using the arrival-at-end timing AEs calculated in the process of S136 (S126).

As described above, in the present embodiment, the arrival end timing AEs appropriate for suppressing HC is determined based on the retard guard value AEth. This processing is in view of being more difficult to be affected by the intake phase difference DIN and the charging efficiency η in comparison with the timing proper in terms of suppressing PN. Further, as compared with the processing of S124 in fig. 12, it is possible to more easily match the timing appropriate for suppressing HC and to suppress the arrival end timing AEs of PN as much as possible.

< correspondence relationship >

[8] The "multi-ejection process" corresponds to the process of S130 performed following the process of S128. The "advance angle processing" corresponds to the processing of S120 to S124 in fig. 12 and the processing of S122a, S120, S134, and S136 in fig. 15.

[9] The "valve characteristic varying device" corresponds to the intake valve timing adjusting device 44, and the "valve characteristic control process" corresponds to the target intake phase difference calculating process M12 and the intake phase difference control process M14. The "variable processing" corresponds to the processing of S122 and S124 in fig. 12 and the processing of S122a in fig. 15.

The "reference timing setting process" corresponds to the process of S122a in fig. 15, and the "guard value setting process" corresponds to the process of S134 in fig. 15. The "low temperature timing setting process" corresponds to the process of S136 of fig. 15.

"required injection amount calculation processing" corresponds to the processing of S112.

"temperature of the intake system" corresponds to the water temperature THW.

< other embodiment >

"protection value setting processing"

In the above embodiment, the hysteresis angle protection value AEth is calculated based on the water temperature THW and the rotation speed NE, but the present invention is not limited to this. For example, the delay angle protection value AEth may be calculated based on only the water temperature THW, and the delay angle protection value AEth may be calculated using only one of the two parameters, i.e., the water temperature THW and the rotation speed NE.

"about variable processing"

In the above embodiment, the end-of-arrival timings AEs, AEsa, AEsb are set based on the rotation speed NE, the charging efficiency η, the water temperature THW, and the intake phase difference DIN, but not limited thereto. As the parameter (parameter indicating the load) indicating the amount of air to be charged into the combustion chamber 24, for example, the basic injection amount Qb may be used instead of the charging efficiency η. The end-of-arrival timings AEs, AEsa, AEsb may be variably set based on only three of the four parameters of the rotation speed NE, the load, the water temperature THW, and the intake phase difference DIN, or may be variably set based on only two of the parameters. For example, the end-of-arrival timings AEs, AEsa, AEsb, and the like may be variably set based on only the intake phase difference DIN among the four parameters of the rotation speed NE, the load, the water temperature THW, and the intake phase difference DIN, and may be variably set based on only one parameter.

Further, for example, instead of calculating the arrival end timings AEs, AEsa, AEsb, a delay amount with respect to the opening start timing of the intake valve 18 may be set. At this time, the retardation amount may be variably set based on a parameter other than the intake phase difference DIN among the parameters used for calculating the arrival end timing AEs.

The injection start timing Is of the intake synchronous injection Is calculated after the arrival end timings AEs, AEsa, AEsb and the retard amount are calculated. For example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data in which one of four parameters, for example, the intake phase difference DIN, among the rotation speed NE, the load, the water temperature THW, and the intake phase difference DIN, Is used as an input variable, and the injection start timing Is of the intake-synchronized injection Is used as an output variable. Further, for example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data in which two parameters, such as the rotation speed NE and the charging efficiency η, among the four parameters, are input variables and the injection start timing Is of the intake-synchronized injection Is an output variable. In this case, the calculated injection start timing Is of the intake-air-synchronized injection may be corrected in accordance with the water temperature THW. Further, for example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data that uses three parameters, such as the rotation speed NE, the charging efficiency η, and the intake phase difference DIN, among the four parameters, as input variables and uses the injection start timing Is of the intake-synchronized injection as an output variable. In this case, the calculated injection start timing Is of the intake-air-synchronized injection may be corrected in accordance with the water temperature THW. Further, for example, the injection start timing Is of the intake-synchronized injection may be calculated based on map data having the rotation speed NE, the charging efficiency η, the intake phase difference DIN, and the water temperature THW as input variables and having the injection start timing Is of the intake-synchronized injection as an output variable.

"temperature of catalyst"

In the above embodiment, the temperature of the catalyst 34 is grasped by the warm-up count C, but the present invention is not limited thereto. For example, an integrated value of only the intake air amount Ga may be used. The integrated value updating process here is a process of updating the integrated value by an update amount uniquely determined in accordance with the intake air amount Ga regardless of the size of the integrated value. For example, a temperature sensor such as a thermocouple may be provided in the catalyst 34 and the detection value of the temperature sensor may be used.

"temperature in relation to air intake System"

In the above embodiment, the water temperature THW is used as the temperature of the intake system, but the present invention is not limited to this. For example, the temperature of the lubricating oil of the internal combustion engine 10 may also be used.

"regarding required injection quantity"

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

Note that, at the time of cold start of the internal combustion engine 10, the injection amount increases regardless of the charging efficiency η, and therefore PN tends to increase even when the single injection process is executed. Therefore, the air flow meter 62 cannot accurately recognize the intake air amount Ga at the time of startup, and therefore, even when the required injection amount Qd is determined based on the water temperature THW regardless of the intake air amount Ga, the multi-injection process can be executed. Even in this case, it Is effective to set the injection start timing Is of the intake-synchronized injection to the advanced side when the temperature of the catalyst 34 Is low, as compared with when the temperature of the catalyst 34 Is high.

"intake asynchronous injection with multiple injection treatment"

In the above embodiment, the intake-asynchronous injection is performed such 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 converges to the closing period of the intake valve 18, but the present invention is not limited thereto. For example, when the rotation speed NE is high and the asynchronous injection amount Qns is excessive, 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 may overlap the opening period of the intake valve 18.

"about Single shot treatment"

In the above embodiment, the single injection process is performed to inject the fuel 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 converges to the closing period of the intake valve 18, but the present invention 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 may overlap the opening period of the intake valve 18. It is noted that it is not necessary to perform a single injection process.

"method of dispensing required amount of spray"

In the above embodiment, the synchronous injection amount Qs is variably set based on the rotation speed NE, the charging efficiency η, the water temperature THW, and the intake phase difference DIN, but is not limited thereto. For example, the basic injection amount Qb may be used instead of the filling efficiency η as a load parameter that is a parameter indicating the amount of air filled into the combustion chamber 24. The four parameters of the load parameter, the rotation speed NE, the water temperature THW, and the intake air phase difference DIN may be variably set based on only three of them, or may be variably set based on only two of them, or may be variably set based on only one of them. In this case, it is preferable to variably set at least one of the load parameter and the water temperature THW as much as possible. Further, in addition to the above-described four parameters, for example, the intake pressure or the flow rate of the intake air may be used. However, from the above four parameters, the intake air pressure and the flow rate of the intake air can be grasped.

It is not essential to calculate the synchronous injection amount Qs to allocate the required injection amount Qd, and 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 the load, for example. For example, the value "KAF · Qb" obtained by correcting the base injection amount Qb by the feedback correction coefficient KAF may be assigned to the synchronous injection amount Qs by using the synchronous injection ratio Ks. In this case, the synchronized injection amount Qs becomes "Ks · KAF · Qb".

"control process for valve characteristics"

In the above embodiment, the target intake phase difference DIN is variably set in accordance with the rotation speed NE and the charging efficiency η, but is not limited thereto. For example, when the water temperature THW is low, the actual timing may be exceptionally limited to the retarded side with respect to the opening timing of the intake valve 18 determined based on the rotation speed NE and the charging efficiency η.

Devices relating to variation of characteristics of inlet valves "

"about control device"

The control device is not limited to being provided with the CPU52 and the ROM54 and executing software processing. For example, a dedicated hardware circuit (e.g., ASIC) may be provided for performing hardware processing on at least a part of the software-processed part in the above-described embodiment. That is, the control device may have any one of the following configurations (a) to (c). (a) The processing device includes a processing device that executes all of the above-described processing in accordance with a program, and a program storage device (including a non-transitory computer-readable recording medium) such as a ROM that stores the program. (b) The apparatus includes a processing device for executing a part of the above-described processing in accordance with a program, a program storage device, and a dedicated hardware circuit for executing the remaining processing. (c) The apparatus includes a dedicated hardware circuit for executing all of the above-described processing. Here, the number of the software processing circuits and the dedicated hardware circuits provided with the processing device and the program storage device may be plural. That is, the above-described 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.

"other"

It is not necessary to have a GPF 136.

Claims

1. A control device for an internal combustion engine, wherein,

the internal combustion engine to which the control device is applied is provided with a port injection valve that injects fuel into an intake passage,

the control device is configured to execute:

and a variable processing for variably setting an injection timing of the intake-synchronized injection, which is expressed by a rotation angle of a crankshaft of the internal combustion engine, based on at least two parameters among three parameters, which are a rotation speed of the crankshaft of the internal combustion engine, a valve-opening start timing of the intake valve that changes an overlap amount of the intake valve and the exhaust valve, and a temperature of an intake system of the internal combustion engine.

2. The control device of an internal combustion engine according to claim 1,

the control device is configured to further execute a required injection amount calculation process of calculating the required injection amount as an injection amount for controlling an air-fuel ratio to a target air-fuel ratio based on a fresh air amount charged into a cylinder of the internal combustion engine,

3. The control device of an internal combustion engine according to claim 2,

the variable processing includes:

4. The control device of an internal combustion engine according to claim 3,

the internal combustion engine includes a valve characteristic varying device configured to vary a valve characteristic of the intake valve,

5. The control device of an internal combustion engine according to claim 1 or 2, wherein,

the variable processing includes:

6. The control device of an internal combustion engine according to claim 5,

the end timing setting process includes a process of variably setting the end reaching timing based on a load of the internal combustion engine in addition to the rotation speed.

7. The control device of an internal combustion engine according to claim 6,

the control device further executes a valve characteristic control process of variably controlling a valve opening start timing of the intake valve by operating the valve characteristic variable device,

8. The control device of an internal combustion engine according to any one of claims 1 to 4,

the internal combustion engine further includes a catalyst that purifies exhaust gas discharged to the exhaust passage,

9. The control device of an internal combustion engine according to claim 8,

the internal combustion engine is provided with a valve characteristic changing device for changing the valve characteristic of an intake valve,

the variable processing variably sets the injection timing of the intake-synchronized injection in accordance with the valve-opening start timing of the intake valve,

the variable processing includes:

10. A control method of an internal combustion engine, wherein,

the internal combustion engine includes a port injection valve that injects fuel into an intake passage,

the control method includes:

11. A non-transitory computer-readable storage medium storing a program for causing a processing device to execute a control process of an internal combustion engine,

the control process includes:

and a variable processing for variably setting an injection timing of the intake-synchronized injection expressed by a rotation angle of a crankshaft of the internal combustion engine based on at least two parameters among three parameters, a rotation speed of the crankshaft of the internal combustion engine, a valve-opening start timing of the intake valve that changes an overlap amount of the intake valve and the exhaust valve, and a temperature of an intake system of the internal combustion engine.