JP2000179380A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a control device for internal combustion engine which can maintain as good engine combustion status as that obtained when the engine is warm even if fuel ignition timing is retarded when the engine is cold. SOLUTION: An injector 26 directly injects fuel into a combustion chamber 16 of an engine 10. If uniform combustion is selected as a combustion type of the engine 10, an electronic control unit(ECU) 40 changes fuel injection timing from an early stage of the intake stroke to a late stage when cooling water temperature detected by a water temperature sensor 56 is lower than the specified temperature. Furthermore, the ECU 40 adjusts the fuel injection quantity to be increased according to the extent of retard to prevent air-fuel ratio from becoming lean due to retarded fuel injection timing.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device applied to a spark ignition type internal combustion engine in which fuel is directly injected into a cylinder, and more particularly, to a control device which is set in the first half of an intake stroke when the engine is warm. The present invention relates to a control device for an internal combustion engine that changes a fuel injection timing to a retarded timing when the engine is cold.

[0002]

2. Description of the Related Art In a spark ignition type internal combustion engine in which fuel is directly injected into a cylinder from a fuel injection valve, a rich mixture which injects fuel during a compression stroke and can ignite near an ignition plug. Combustion in which combustion is performed with uneven distribution of fuel-A combustion mode such as homogeneous combustion, in which fuel is injected during the intake stroke to make the air-fuel mixture in the cylinder substantially homogeneous and performs combustion, is selected according to the engine operating condition.

In such a direct injection type internal combustion engine, there is a tendency that the injected fuel and the intake air are less likely to be homogeneously mixed than in an internal combustion engine in which fuel is injected into an intake passage. In an internal combustion engine that injects fuel into the intake passage, the injected fuel is mixed with intake air to some extent in the intake passage and flows into the cylinder, whereas in an in-cylinder internal combustion engine, such mixing is performed. Because there is no. For this reason, when performing homogeneous combustion in the in-cylinder injection type internal combustion engine, by setting the fuel injection timing in the first half of the intake stroke, the mixing time of the injected fuel and the intake air is ensured as much as possible. I have.

[0004] By the way, when the engine is cold, atomization of the injected fuel is not easily promoted by the heat of the engine, so the injected fuel injected in the first half of the intake stroke collides with the top surface of the piston and is not sufficiently atomized. It will rebound to the spark plug as it is. As a result, the liquid injection fuel adheres to the electrodes of the ignition plug, and the insulation resistance between the electrodes decreases, which may cause a misfire in the worst case.

In particular, in an internal combustion engine that performs stratified charge combustion, a recess is formed in the top surface of a piston to direct the flow of injected fuel injected during the compression stroke toward the spark plug, and a combustible mixture is provided near the spark plug. In many cases, an air layer is formed. In this case, the amount of fuel attached to the ignition plug is further increased.

In order to suppress the rebound of the injected fuel, it is effective to change the fuel injection timing as described in Japanese Patent Application Laid-Open No. 9-68072. That is,
If the fuel injection timing set in the first half of the intake stroke is retarded when the engine is cold and fuel is injected when the top surface of the piston is separated from the spark plug, the fuel will collide with the top surface and rebound. It is possible to reduce the amount of fuel and suppress the adhesion of fuel to the ignition plug.

[0007]

However, when the fuel injection timing is retarded in this way, the engine combustion state changes, and it becomes difficult to secure a good engine combustion state equivalent to that during the engine warm state. .

The reasons are as follows: When the engine is warm, the injected fuel that has collided with the top surface of the piston or the inner peripheral wall surface of the cylinder is rapidly atomized and mixed with the intake air. On the other hand, when the fuel injection timing is retarded when the engine is cold, atomization of the injected fuel due to the heat of the engine, particularly the heat of the piston top surface, cannot be expected, and the inner peripheral wall surface of the cylinder is not covered by the piston. Since the area of the portion is increased, the amount of fuel remaining on the inner peripheral wall and not contributing to combustion increases, and the air-fuel ratio becomes leaner than when the engine is warm.

When the fuel is injected in the first half of the intake stroke at the time of engine warm, the top surface of the piston and the spark plug are close to each other, so that the injected fuel colliding with the top surface floats around the spark plug. become. Although this injected fuel is mixed with intake air introduced into the cylinder as the piston descends, it is rarely uniformly dispersed in the cylinder until ignition. Therefore, the ignition is performed while the rich mixture is unevenly distributed around the ignition plug.

On the other hand, when the fuel injection timing is retarded when the engine is cold, the rich air-fuel mixture is not unevenly distributed around the spark plug as described above. Is not promoted, and the particle diameter increases, so that the injected fuel is rather unevenly distributed in a lower portion of the cylinder, that is, a portion remote from the spark plug. Therefore, when the fuel injection timing is retarded when the engine is cold, the air-fuel mixture around the ignition plug becomes leaner than when the engine is warm. When the air-fuel mixture around the ignition plug leans, the combustion speed of the air-fuel mixture decreases, and the period from ignition to the maximum combustion pressure in the cylinder becomes longer. Will be delayed from a timing suitable for securing the engine output.

When the temperature of the engine is warm, the atomization of the injected fuel is promoted by the heat of the engine, especially the heat of the top surface of the piston. It is not possible to expect the promotion of atomization due to the heat of the top surface, and the injected fuel will be mixed with the intake air with its particle size being large, so combustion will be performed with insufficient mixing with the intake air Become like It is conceivable.

As described above, since the air-fuel ratio, the generation timing of the maximum combustion pressure, or the degree of atomization of the injected fuel changes, conventionally, when the fuel injection timing is retarded when the engine is cold,
It has become impossible to maintain a good engine combustion state equivalent to that during the engine warm state, leading to a decrease or fluctuation in engine output and a deterioration in fuel economy.

The present invention has been made in view of such a conventional situation, and an object thereof is to provide a good engine combustion state substantially equal to that during the engine warm even when the fuel injection timing is retarded when the engine is cold. An object of the present invention is to provide a control device for an internal combustion engine that can be maintained.

[0014]

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 is applied to a spark ignition type internal combustion engine in which fuel is directly injected into a cylinder,
In an internal combustion engine control device having a fuel injection timing changing means for changing a fuel injection timing set in the first half of an intake stroke at the time of engine warm to a timing on the retard side at the time of engine cold, an engine associated with a change of fuel injection timing is provided. In order to suppress a change in the combustion state, a control amount changing means for changing a control amount of the internal combustion engine which affects the combustion state of the engine between an engine warm state and an engine cold state is provided.

According to such a configuration, the control amount changing means changes the control amount of the internal combustion engine which affects the engine combustion state, so that the change in the engine combustion state due to the change in the fuel injection timing is suppressed. become. Incidentally, such control amounts of the internal combustion engine include a fuel injection amount, an ignition timing, an adjustment amount of an adjustment mechanism for adjusting the intensity of swirl generated in the cylinder, a fuel injection pressure, an opening / closing timing of an intake valve or an exhaust valve, and a lift amount. And the amount of adjustment of the intake air amount adjustment mechanism.

Further, as in the invention according to claim 2,
In the configuration according to claim 1, the fuel injection timing changing means sets the retard amount of the fuel injection timing to be larger as the engine temperature becomes lower, and the control amount changing means sets the retard amount as the retard amount becomes larger. By adopting a configuration in which the change rate of the control amount is set to a large value, when suppressing the fuel adhesion to the ignition plug by retarding the fuel injection timing, the retard amount is minimized. In order to suppress a change in the engine combustion state due to the retardation of the fuel injection timing, a more appropriate change rate of the control amount can be set.

Further, as in the invention described in claim 3,
3. The control device for an internal combustion engine according to claim 1, wherein the control amount changing means controls the fuel injection amount of the internal combustion engine when the engine is cold so as to suppress the air-fuel ratio from becoming lean with a change in the fuel injection timing. If the fuel injection amount is increased from the fuel injection amount at the time of engine warm, the air-fuel ratio is corrected to the rich side by the increase in the fuel injection amount. Lean can be suppressed.

In particular, if the above-described configuration is adopted in the control device for an internal combustion engine according to the second aspect, that is, if the configuration in which the increasing rate of the fuel injection amount is increased as the retard amount of the fuel injection timing is increased, When suppressing the leaning of the air-fuel ratio due to the retardation of the fuel injection timing by increasing the fuel injection amount, a more appropriate increase ratio can be set.

Further, as in the invention described in claim 4,
3. The control device for an internal combustion engine according to claim 1, wherein the control amount changing unit controls the internal combustion engine when the engine is cold in order to suppress a timing of occurrence of a maximum combustion pressure from being retarded with a change in a fuel injection timing. If the ignition timing of the engine is advanced than the ignition timing at the time of the engine warm, the generation timing of the maximum combustion pressure is corrected to the advanced timing by the advancement of the ignition timing, and the fuel is advanced. It is possible to prevent the occurrence timing of the maximum combustion pressure from changing to the timing on the retard side with the change of the injection timing.

In particular, if the above configuration is adopted in the control device for an internal combustion engine according to the second aspect, that is, if the advance amount of the ignition timing is increased as the retard amount of the fuel injection timing is increased, When the generation timing of the maximum combustion pressure is suppressed from changing to the timing on the retard side by the advancement of the ignition timing, a more appropriate advance amount can be set.

Also, as in the invention according to claim 5,
The control device for an internal combustion engine according to claim 1 or 2, wherein the control amount changing means is provided in the cylinder when the engine is cold to suppress a decrease in the degree of atomization of the injected fuel due to a change in the fuel injection timing. By adopting a configuration that increases the intensity of the generated swirl than the intensity at the time of engine warm, the atomization of the injected fuel is promoted by increasing the intensity of the swirl, and the change of the fuel injection timing As a result, the degree of atomization of the injected fuel is reduced, and the change in the combustion state can be suppressed.

In particular, if the above-mentioned configuration is adopted in the control device for an internal combustion engine according to the second aspect, that is, if the configuration in which the swirl intensity is increased as the retard amount of the fuel injection timing is increased is adopted, When the decrease in the degree of atomization is suppressed by increasing the swirl strength, a more appropriate increase rate can be set.

Further, as in the invention described in claim 6,
In the configuration according to any one of claims 3 to 5, if the control amount changing means further employs a structure in which the throttle opening is made larger than the opening when the engine is warm when the engine is cold. In addition, the pumping loss when the engine is cold is reduced compared to when the engine is warm, and the engine output when the engine is cold is increased.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] A first embodiment of the present invention will be described below.

FIG. 1 shows a schematic configuration of a control device of an engine 10 according to the present embodiment. The engine 10 includes a cylinder head 11 and a cylinder block 12 in which a plurality of cylinders 13 (only one of them is shown in FIG. 1). A piston 14 is provided in each cylinder 13 so as to be able to reciprocate. A combustion chamber 16 is defined by a top surface of the piston 14, an inner peripheral wall surface of the cylinder 13 and a lower surface of the cylinder head 11.

In the cylinder head 11, a pair of intake ports 30a and 30b forming a part of the intake passage 30 and a pair of exhaust ports 32a and 3 forming a part of the exhaust passage 32 are provided.
2b (in FIG. 1, one of the intake ports 3
0a and only the exhaust port 32a). The intake ports 30a, 30b and the exhaust ports 32a, 32b are communicated with the combustion chamber 16, and are opened and closed by opening and closing the intake valve 20 and the exhaust valve 22 supported on the cylinder head 11.

FIG. 2 shows a plan sectional shape of each of the intake ports 30a and 30b and the exhaust ports 32a and 32b. As shown in the figure, one intake port 30a is a straight port extending linearly, while the other intake port 30b is a helical port whose axis extends in a curved manner (hereinafter, particularly, a helical port). These intake ports 30
a and 30b are referred to as “straight port 30a” and “helical port 30b” respectively). After passing through the helical port 30b, the combustion chamber 16
When the intake air is introduced into the combustion chamber 16, a flow of the intake air swirling around the axis of the piston 14 (see FIG. 1), that is, swirl, is formed in the combustion chamber 16 as shown by a dashed arrow.

As shown in FIG. 1 and FIG.
A swirl control valve (hereinafter abbreviated as “SCV”) 34 that is opened and closed by a motor 35 is provided in a portion communicating with the straight port 30a on the upstream side.
Is provided. The SCV 34 controls the strength of the swirl formed in the combustion chamber 16 by opening and closing the straight port 30a and adjusting the amount of intake air passing through the helical port 30b.

When the opening of the SCV 34 is relatively small, the proportion of the intake air passing through the intake passage 30 that passes through the helical port 30b is increased, and the swirl strength is increased. As the ratio becomes larger, the ratio decreases and the swirl strength decreases.

As shown in FIG. 1, a surge tank 36 is provided in a portion of the intake passage 30 upstream of the SCV 34, and a throttle valve 38 is provided in a portion of the intake passage 30 upstream of the surge tank 36. Have been. This throttle valve 38 is a throttle motor 39
The opening / closing drive causes the amount of intake air introduced into the combustion chamber 16 to be determined by its opening degree, that is, the throttle opening degree TA.
Adjust according to.

The surge tank 36 includes
One end of a purge passage 37 that communicates with a canister (not shown) is connected. The purge passage 37 is provided with a purge amount control valve 33, and the amount of fuel purged from the canister into the surge tank 36 is adjusted by the purge amount control valve 33.

The cylinder head 11 is provided with an injector 26 for directly injecting fuel into the combustion chamber 16, corresponding to each combustion chamber 16. The injector 26 is connected to a delivery pipe (not shown) through which high-pressure fuel is fed from a fuel pump (not shown), and the fuel is supplied from the delivery pipe. The injector 26 has a built-in solenoid valve (not shown), and the fuel injection amount and the fuel injection timing are adjusted based on the opening / closing operation of the solenoid valve.

The cylinder head 11 is provided with an ignition plug 24 corresponding to each combustion chamber 16, and an electrode portion at the tip protrudes into the combustion chamber 16. The ignition plug 24 is connected to an igniter 25 via an ignition coil (not shown), and the ignition timing is adjusted by the igniter 25. An air-fuel mixture formed by intake air introduced into the combustion chamber 16 from the intake passage 30 when the intake valve 20 is opened and fuel directly injected from the injector 26 into the combustion chamber 16 is ignited by the ignition plug 24. Being burned. The air-fuel mixture thus burnt is exhausted from the combustion chamber 16 as exhaust gas when the exhaust valve 22 is opened.
It is discharged to 2.

A recess 14a is formed on the top surface of the piston 14. When the piston 14 and the injector 26 are close to each other as in the latter half of the compression stroke, the injector 2
The fuel injected from the nozzle 6 along with the swirl is directed toward the tip of the spark plug 24 by the recess 14a.

The engine 10 according to the present embodiment has a plurality of modes having different air-fuel ratios or fuel injection systems, ie, a plurality of modes.
The combustion mode is switched between "stratified combustion", "weak stratified combustion", and "homogeneous combustion". Such switching of the combustion mode is performed based on the fuel injection amount and the engine speed.

For example, if "stratified combustion" is selected as the combustion mode, the air-fuel ratio becomes the stoichiometric air-fuel ratio (A / F = 14.5).
(A / F = 25 to 50), and the fuel injection timing is set in the latter half of the compression stroke. When "weak stratified charge combustion" is selected as the combustion mode, the air-fuel ratio is set to be leaner (A / F = 20 to 30) than the stoichiometric air-fuel ratio, and the fuel is divided into the intake stroke and the compression stroke. It will be divided into times and injected. Further, when “homogeneous combustion” is selected as the combustion mode, the air-fuel ratio is determined based on the stoichiometric air-fuel ratio, lean (A / F = 15 to 23), and rich (A / F = 11 to 13) according to the operation state. The fuel injection timing is set as appropriate, and the fuel injection timing is set during the intake stroke.

The engine 10 is provided with various sensors for detecting its operating state. A crankshaft (not shown) that rotates with the reciprocation of the piston 14 and a camshaft that rotates in conjunction with the crankshaft are provided near the crankshaft rotation speed (engine speed N).
E) and a cam angle sensor 52 for detecting a rotation angle (crank angle CA).

The surge tank 36 is provided with an intake pressure sensor 53 for detecting the pressure of the intake air (intake pressure PM). The accelerator pedal 6 is located near the throttle valve 38.
An accelerator sensor 54 for detecting a depression amount of 0 (accelerator opening ACCP) is provided. An SCV opening sensor 55 for detecting the opening (actual opening SCVP) of the SCV 34 is provided near the SCV 34.

The cylinder block 12 has a water temperature sensor 56 for detecting the temperature of the cooling water (cooling water temperature THW).
(Constituting the engine temperature detecting means), and a knocking signal KC corresponding to the magnitude of knocking generated in the engine 10.
A knock sensor 57 that outputs S is provided. Further, the exhaust passage 32 is provided with an oxygen sensor 58 that outputs an exhaust oxygen concentration signal XOX corresponding to the oxygen concentration of the exhaust flowing through the exhaust passage 32.

Each of the detection signals output from these various sensors 51 to 58 is an electronic control unit (hereinafter abbreviated as “ECU”) 40 for executing various controls of the engine 10.
Is input to The ECU 40 includes these sensors 51 to 51
By driving the injector 26 (electromagnetic valve), the igniter 25, the purge amount control valve 33, each of the motors 35 and 39, etc. based on the detection signal from 58, control relating to the fuel injection amount and fuel injection timing and ignition timing control , An air-fuel ratio feedback control, a purge amount control, an intake air amount control, a control relating to a swirl intensity, and the like. The ECU 40 includes a central processing unit (CPU) 41 that performs arithmetic processing when performing such various controls, a memory 42 in which various control programs and function data are stored in advance, or a memory 42 for storing various data. I have.

The procedure for executing various controls when "homogeneous combustion" is selected as the combustion mode among the controls executed by the ECU 40 will be described below. First, the fuel injection timing control in the present embodiment will be described.

FIG. 3 is a flowchart showing the procedure for executing the fuel injection timing control. The ECU 40 repeatedly executes the "fuel injection timing control routine" as an interruption process of a predetermined crank angle cycle.

First, at step 100, the intake pressure P
Fuel injection timing AINJ based on M and engine speed NE
Is calculated. The fuel injection timing AINJ is defined as a relative crank angle CA before the compression top dead center (BTDC) with reference to the compression top dead center (TDC) of the cylinder in which ignition is performed. Therefore, as the fuel injection timing AINJ increases, the fuel is injected at a relatively advanced timing, and conversely, as the fuel injection timing AINJ decreases, the fuel is injected at a relatively retarded timing.

Next, at step 110, the cooling water temperature THW is compared with the judgment temperature JTHW. This determination temperature JTHW is a value for determining whether or not it is necessary to retard the fuel injection timing AINJ in order to suppress the adhesion of fuel to the ignition plug 24. If it is determined that the cooling water temperature THW is lower than the determination temperature JTHW, the process proceeds to step 120, and the fuel injection timing AINJ is set equal to the cold injection timing AINJCOLD. The cold injection timing AINJCOLD is a fuel injection timing that is set so as to reliably suppress the adhesion of fuel to the ignition plug 24. The fuel injection timing set in step 100 based on the intake pressure PM and the engine speed NE. Injection timing AINJ
(For example, BTDC 300 ° -360 ° CA) on the retard side (for example, BTDC 260 ° CA).

Then, in step 130, the delay processing execution flag XCOLD is set to "1". The retarding process execution flag XCOLD determines whether or not a process of retarding the fuel injection timing AINJ (hereinafter, referred to as “injection timing retarding process”) is being performed in order to suppress fuel adhesion to the spark plug 24. This is a flag for performing

On the other hand, at step 110, the cooling water temperature T
If it is determined that the HW is equal to or higher than the determination temperature JTHW, that is, it is determined that it is not necessary to execute the injection timing retarding process,
At 40, the retard processing execution flag XCOLD is reset to "0". After executing the processing of step 130 or step 140, the ECU 40 once ends the processing of this routine.

Next, the fuel injection amount control in this embodiment will be described. FIG. 4 is a flowchart showing the procedure for executing the fuel injection amount control. The ECU 40 repeatedly executes the "fuel injection amount control routine" as an interruption process of a predetermined crank angle cycle.

In this "fuel injection amount control routine", an increase correction of the fuel injection amount is executed based on the retard processing execution flag XCOLD set in the "fuel injection timing control routine".

First, at step 200, the intake pressure P
M and the basic fuel injection amount QIN based on the engine speed NE.
Calculate JB. The basic fuel injection amount QINJB is a reference for the fuel injection amount, and is calculated as a larger value to secure a predetermined engine output as the intake pressure PM or the engine speed NE increases.

Next, in step 210, it is determined whether or not the retard processing execution flag XCOLD is set to "1", that is, whether or not the injection timing retard processing is being executed. Here, if it is determined that the delay processing execution flag XCOLD is “0”, the injection timing delay processing is stopped, and the processing shifts to step 240.

On the other hand, if it is determined in step 210 that the retard processing execution flag XCOLD is "1",
In step 220, the intake pressure PM and the engine speed N
The basic fuel injection amount QINJBCOLD during cold is calculated based on E, and the basic fuel injection amount QIN
JB is set equal to this cold injection amount QINJBCOLD.

In the memory 42 of the ECU 40, the intake pressure PM, the engine speed NE, and the cold basic injection amount QINJBCOL are stored.
Function data defining the relationship with D is stored, and E
The CU 40 refers to this function data when calculating the cold injection amount QINJBCOLD. Here, the cold basic injection amount QINJBCOLD is set to be always larger than the basic fuel injection amount QINJBB calculated in step 200.
The difference in QINJB, that is, the increase rate of the fuel injection amount at the time of executing the injection timing retardation processing is set so as to be able to compensate for the deviation amount of the air-fuel ratio shifted to the lean side with the execution of the injection timing retardation processing. ing.

In step 240, the fuel injection time TAU is calculated based on the following equation. TAU = QINJB × (FAF + KG) × KM (1) where “FAF” is an air-fuel ratio feedback correction coefficient set based on the exhaust oxygen concentration signal XOX and the like, and “KG”
Is an air-fuel ratio learning value for correcting a steady-state deviation generated between the target air-fuel ratio (theoretical air-fuel ratio) and the actual air-fuel ratio.
“KM” is a correction coefficient set based on the fuel injection pressure (fuel pressure in the delivery pipe), the intake air temperature, and the like.

After setting the fuel injection time TAU in step 240, the processing of this routine is temporarily terminated. The ECU 40 executes fuel injection by driving the solenoid valve of the injector 26 based on the fuel injection time TAU and the fuel injection timing AINJ determined in each of the above control routines.

As described above, in the present embodiment, when the injection timing retarding process is performed, the basic fuel injection amount QIN
Since the cold basic injection amount QINJBCOLD is selected as JB, more fuel is injected than when the engine is warm. Therefore, the cylinder 13
Even when the engine is cold, the amount of fuel adhering to the inner peripheral wall of the engine has increased and the amount of fuel actually contributing to combustion has decreased, the decrease in fuel can be offset by the increase in the fuel injection amount. It becomes possible to inject fuel in an amount corresponding to the amount of intake air introduced into the chamber 16.

Therefore, according to the present embodiment, (1) it is possible to secure a favorable combustion state by suppressing a lean deviation of the air-fuel ratio due to the injection timing retarding process, and to cause such a deviation of the air-fuel ratio. It becomes possible to suppress a decrease or fluctuation of the engine output.

[Second Embodiment] Next, a second embodiment of the present invention will be described, focusing on differences from the first embodiment. The description of the same configuration as that of the first embodiment is omitted.

In the present embodiment, in addition to the "fuel injection timing control routine" and the "fuel injection amount control routine" described in the first embodiment, ignition is performed according to whether or not the injection timing retarding process is being executed. The point that the timing is corrected is different from the first embodiment.

Hereinafter, the execution procedure of the ignition timing control will be described with reference to a flowchart shown in FIG.
The ECU 40 repeatedly executes the “ignition timing calculation routine” as an interruption process of a predetermined crank angle cycle.

First, at step 300, the intake pressure PM
And the basic ignition timing ABSE is calculated based on the engine speed NE. Function data defining the relationship between the intake pressure PM, the engine speed NE, and the basic ignition timing ABSE is stored in the memory 42 of the ECU 40, and the ECU 40 refers to this function data when calculating the basic ignition timing ABSE. . The basic ignition timing ABSE is also the fuel injection timing AINJ
Similarly to the above, it is defined as a relative crank angle CA before the compression top dead center.

Next, at step 310, it is determined whether or not the retard processing execution flag XCOLD is set to "1". If it is determined that the delay processing execution flag XCOLD is "1", that is, if it is determined that the injection timing delay processing is being executed, the process proceeds to step 320.
Move to

In step 320, the basic ignition timing ABSE during cold is determined based on the intake pressure PM and the engine speed NE.
After calculating COLD, in step 330, the basic ignition timing ABSE is changed to the cold basic ignition timing ABSEC.
Set equal to OLD.

The memory 42 of the ECU 40 stores the intake pressure PM, the engine speed NE and the cold basic ignition timing ABSECOL.
Function data defining the relationship with D is stored, and E
The CU 40 refers to this function data when calculating the cold basic ignition timing ABSECOLD.

This cold basic ignition timing ABSECOLD
Is the basic ignition timing A calculated in step 300
It is set so that it is always larger than BSE, that is, it is always on the advance side.

If the fuel injection timing is retarded when the engine is cold, even if the overall air-fuel ratio in the cylinder 13 is suppressed from deviating to the lean side due to the increase in the basic fuel injection amount QINJB, the fuel spray particles Since the diameter is large, the spray is unevenly distributed below the cylinder 13, and it is unavoidable that the mixture around the spark plug 24 becomes partially lean.

When the air-fuel mixture around the ignition plug 24 is partially lean, the combustion speed of the air-fuel mixture is reduced, and the timing (crank angle CA) at which the maximum combustion pressure is generated is suitable for securing the engine output. It will be later than the time. Above cold basic ignition timing ABSECOLD and basic ignition timing A
The difference from the BSE, that is, the advance amount of the ignition timing at the time of executing the injection timing delay processing is set so as to be able to compensate for the delay in the generation timing of the maximum combustion pressure.

When it is determined in step 310 that the injection timing retarding process has been stopped, or in step 33
After executing the process of step S340, the final ignition timing AO is determined in step 340 based on the basic ignition timing ABSE and the knocking signal KCS output from the knock sensor 57.
Calculate P. After executing the process of step 340, the process of this routine is temporarily ended.

The ECU 40 calculates the crank angle C before the compression top dead center.
When A coincides with the final ignition timing AOP, an ignition signal is output to the igniter 25 to execute ignition by the ignition plug 24.

As described above, in the present embodiment, when the injection timing retarding process is executed, the basic ignition timing ABS
Since the cold basic ignition timing ABSECOLD is selected as E, the mixture is ignited earlier than when the engine is warm.

Therefore, according to the present embodiment, (2) a favorable combustion state is achieved by suppressing the timing of occurrence of the maximum combustion pressure from being delayed from the timing suitable for securing the engine output by the injection timing retarding process. Can be secured.
Accordingly, it is possible to suppress a decrease or fluctuation of the engine output and a deterioration of the fuel efficiency due to the delay of the timing of the generation of the maximum combustion pressure.

[Third Embodiment] Next, a third embodiment of the present invention will be described, focusing on differences from the first embodiment. The description of the same configuration as that of the first embodiment is omitted.

In the present embodiment, when retarding the fuel injection timing in the injection timing retarding process, the retard amount is variably set based on the cooling water temperature THW, and based on the retard amount of the fuel injection timing. The difference from the first embodiment is that the rate of increase in the fuel injection amount is set.

Hereinafter, the execution procedure of such fuel injection timing control will be described with reference to FIGS. ECU4
A value of 0 repeatedly executes the "fuel injection timing control routine" shown in FIG. 6 as interruption processing of a predetermined crank angle cycle.
Note that in FIG. 6, the steps denoted by the same reference numerals as those in FIG. 3 execute the same processing as in FIG.

After the processing of step 100, step 11
If it is determined at 0 that the injection timing retarding process needs to be executed, the processes of steps 112 to 120 are sequentially executed to correct the fuel injection timing AINJ.

First, at step 112, the cold injection timing AINJCOLD is calculated based on the cooling water temperature THW. Function data defining the relationship between the cooling water temperature THW and the cold injection timing AINJCOLD is stored in the memory 42 of the ECU 40, and the ECU 40 refers to this function data when calculating the cold injection timing AINJCOLD.

FIG. 7 is a graph showing the function data. As shown in the figure, as the cooling water temperature THW becomes lower, the cold injection timing AINJCOLD is set to a more retarded timing.

Next, at step 114, the difference between the fuel injection timing AINJ calculated at step 100 and the cold injection timing AINJCOLD is set as the retard amount △ AINJ. The retardation amount △ AINJ has a correlation with the deviation amount when the air-fuel ratio shifts to the lean side by executing the injection timing retardation processing, and is used when determining the increase rate of the fuel injection amount.

Then, in step 120, the cold injection timing AINJCOLD is changed to the new fuel injection timing AIN.
After the setting as J, in step 130, the retard processing execution flag XCOLD is set to "1".

On the other hand, if it is determined in step 110 that it is not necessary to execute the injection timing retarding process, in step 140, the retarding process execution flag XCOLD is reset to "0". After executing the processing of steps 130 and 140, the processing of this routine is temporarily terminated.

Next, an execution procedure of the fuel injection amount control will be described with reference to FIGS. The ECU 40 repeatedly executes a “fuel injection amount control routine” shown in FIG. 8 as an interruption process of a predetermined crank angle cycle. Note that in FIG. 8, the steps denoted by the same reference numerals as those in FIG. 4 execute the same processes as those in FIG.

After the processing of step 200, step 21
If it is determined at 0 that the injection timing retarding process is being executed, the processes of steps 222 to 232 are sequentially executed to correct the basic fuel injection amount QINJB.

First, at step 222, an injection amount increase coefficient KQ is calculated based on the basic fuel injection amount QINJB (or intake pressure PM) and the retard amount △ AINJ.
This injection amount increase coefficient KQ is for increasing and correcting the fuel injection amount in accordance with the deviation amount when the air-fuel ratio shifts to the lean side by executing the injection timing delay processing.

The memory 42 of the ECU 40 stores the basic fuel injection amount QINJB (or intake pressure PM) and the retard amount 角 AI
Function data that defines the relationship between NJ and the injection amount increase coefficient KQ is stored. FIG. 9 is a graph showing the function data.

As shown in the figure, the larger the retard amount △ AINJ, the larger the injection amount increase coefficient KQ is set.
The reason for setting the injection amount increase coefficient KQ in this manner is as follows.

That is, as is apparent from the relationship among the retard amount △ AINJ, the cold injection timing AINJCOLD, and the cooling water temperature THW, as the retard amount △ AINJ increases, the cooling water temperature THW decreases and the injected fuel is atomized. Because it becomes difficult
The amount of fuel that remains on the inner peripheral wall surface of the cylinder 13 increases.

Further, as the retard amount △ AINJ increases, the distance between the injector 26 and the top surface of the piston 14 when injecting fuel increases, and the portion of the inner peripheral wall surface of the cylinder 13 that is not covered by the piston 14 Therefore, the amount of fuel adhering to the inner peripheral wall surface increases.

Since the air-fuel ratio greatly shifts to the lean side with the increase in the amount of fuel adhesion, in order to correct this shift properly, the retard amount ΔAI
This is because the injection amount increase coefficient KQ needs to be set larger as NJ increases.

The injection amount increase coefficient KQ is set to be larger as the basic fuel injection amount QINJB increases (or the intake pressure PM increases). This is the basic fuel injection amount QIN
This is because, as JB increases, the ratio of the injected fuel adhering to the inner peripheral wall surface of the cylinder 13 increases, and the lean deviation of the air-fuel ratio tends to become more remarkable.

After calculating the injection amount increase coefficient KQ as described above, in step 232, the current basic fuel injection amount QINJB is multiplied by the injection amount increase coefficient KQ, and the multiplied value (QINJB × K) is added to a new value. Basic fuel injection amount QIN
Set as JB.

On the other hand, if it is determined in step 210 that the injection timing delay processing has been stopped, or after the processing in step 232 has been executed, the ECU 40 determines in step 240 the fuel injection time TA based on the above equation (1).
U is calculated, and the processing of this routine is temporarily ended.

As described above, in this embodiment, the fuel injection timing AINJ is set to a relatively retarded timing as the cooling water temperature THW decreases, and the fuel injection timing AINJ is set to a retarded timing. As the setting is made, the basic fuel injection amount QINJB is increased greatly.

Therefore, according to the present embodiment, (3) the retard amount (燃料 AINJ) of the fuel injection timing (AINJ) is suppressed to a necessary minimum in order to suppress the adhesion of fuel to the ignition plug 24, and When the lean deviation of the air-fuel ratio due to the retardation of the fuel injection timing is suppressed by increasing the fuel injection amount, an appropriate increase ratio (injection amount increase coefficient KQ) can be set. As a result, a more favorable engine combustion state is ensured, and it is possible to reliably suppress a decrease or fluctuation in the engine output caused by a lean deviation of the air-fuel ratio.

[Fourth Embodiment] Next, a fourth embodiment of the present invention will be described, focusing on differences from the third embodiment. The description of the same configuration as that of the third embodiment is omitted.

In this embodiment, both the "fuel injection timing control routine" and the "fuel injection amount control routine" shown in FIGS.
The correction is made as necessary based on the NJ. Hereinafter, the calculation procedure of the ignition timing will be described with reference to FIGS.

FIG. 10 is a flowchart showing each process of the "ignition timing calculation routine". The ECU 40 repeatedly executes the “ignition timing calculation routine” as an interruption process of a predetermined crank angle cycle. Note that in FIG. 10, the steps denoted by the same reference numerals as those in FIG. 5 execute the same processes as those in FIG. 5.

After the processing of step 300, step 31
0, when it is determined that the injection timing retarding process is being executed, in step 325, the basic fuel injection amount QI
An ignition timing advance amount KA is calculated based on NJB (or intake pressure PM) and retard amount △ AINJ. This ignition timing advance amount KA is used to advance the ignition timing in accordance with the retard amount when the generation timing of the maximum combustion pressure is delayed from the timing suitable for securing the engine output by the injection timing delay processing. It is for doing.

The memory 42 of the ECU 40 stores the basic fuel injection amount QINJB (or intake pressure PM) and the retard amount △ AIN
Function data that defines the relationship between J and the ignition timing advance amount KA is stored. FIG. 11 is a graph showing the function data.

As shown in the figure, the ignition timing advance amount KA is set to be larger as the retard amount △ AINJ becomes larger.
The reason why the ignition timing advance amount KA is set in this way is as follows.

That is, when the retard amount △ AINJ is increased, that is, when the fuel injection timing is further retarded, the above-described tendency of the mixture around the ignition plug 24 becomes relatively more remarkable. The combustion speed will be greatly reduced. As a result, the timing at which the maximum combustion pressure occurs is further greatly delayed from the timing suitable for securing the engine output. Therefore, in order to suppress such a change in the generation timing of the maximum combustion pressure, it is necessary to set the ignition timing to a more advanced timing as the retard amount △ AINJ increases.

The ignition timing advance amount KA is set to be larger as the basic fuel injection amount QINJB increases (or the intake pressure PM increases). This is the basic fuel injection amount QIN
This is because, as the JB increases, the air-fuel mixture around the ignition plug 24 becomes leaner than the air-fuel mixture in other parts, and the shift in the generation timing of the maximum combustion pressure as described above further increases.

After the ignition timing advance KA is calculated in this way, in step 335, the ignition timing advance KA
Is added to the current basic ignition timing ABSE, and the added value (ABSE + KA) is set as a new basic ignition timing ABSE. After performing the processing of step 335,
Alternatively, if it is determined in step 310 that the injection timing delay processing has been stopped, the ECU 40 proceeds to step 3
At 40, the final ignition timing AOP is calculated, and the processing of this routine is temporarily ended.

As described above, in the present embodiment, the fuel injection timing AINJ set based on the cooling water temperature THW is set.
Is set to the retard side, the basic ignition timing ABSE
Is advanced. Therefore, in addition to the same operation and effect as (3) described in the third embodiment, the following operation and effect can be further obtained.

(4) In order to suppress the adhesion of fuel to the spark plug 24, the timing of generation of the maximum combustion pressure is preferable while the retard amount (量 AINJ) of the fuel injection timing (AINJ) is minimized. It is possible to set an appropriate advance amount (ignition timing advance amount KA) when the deviation from an appropriate timing is suppressed by the advance of the ignition timing. As a result, it is possible to secure a more favorable engine combustion state, to suppress a decrease or fluctuation of the engine output due to a shift in the generation timing of the maximum combustion pressure, and to surely suppress the deterioration of the fuel consumption. become able to.

[Fifth Embodiment] Next, a fifth embodiment of the present invention will be described, focusing on differences from the first embodiment. The description of the same configuration as that of the first embodiment is omitted.

In this embodiment, the "fuel injection timing control routine" shown in FIG. 3 is executed, and the air-fuel ratio learning value KG in the air-fuel ratio control is separately determined during the execution of the injection timing retarding process and during the stop of the same process. It learns as the value of. In this embodiment, the "fuel injection amount control routine" shown in FIG. 4 is not executed, and therefore, the cold basic injection amount QIN
No increase correction of the basic fuel injection amount QINJB based on JBCOLD is performed.

Hereinafter, each process of the "air-fuel ratio control routine" in which the learning of the air-fuel ratio learning value KG is performed will be described with reference to flowcharts shown in FIGS. E
The CU 40 repeatedly executes the “air-fuel ratio control routine” as an interruption process in a predetermined time cycle.

First, at step 500, it is determined whether or not the execution condition of the air-fuel ratio feedback control is satisfied. Here, if it is determined that the execution condition of the air-fuel ratio control is not satisfied, the ECU sets the air-fuel ratio feedback correction coefficient FAF to “1.0” in step 501 and then sets the ECU to “1.0”.
40 temporarily ends the processing of this routine. Incidentally, when the execution condition of the air-fuel ratio control is not satisfied in this way, for example, the cooling water temperature THW is equal to or lower than a predetermined temperature, the accelerator opening ACCP is equal to or higher than a predetermined value,
And so on.

On the other hand, if it is determined in step 500 that the execution condition of the air-fuel ratio control is satisfied,
In 02, it is determined whether or not the purge control is stopped, that is, whether or not the purge passage 37 is closed by the purge amount control valve 33. Here, if it is determined that the purge control is stopped, it is determined in step 504 whether or not the injection timing delay processing is being executed based on the retard processing execution flag XCOLD.

If it is determined in step 504 that the injection timing retarding process is being executed, in step 506, the learned value KGCOLD of the air-fuel ratio during cold is calculated by the ECU 40.
, And sets the cold air-fuel ratio learning value KGCOLD as the air-fuel ratio learning value KG.

On the other hand, if it is determined in step 504 that the injection timing retarding process has been stopped,
7, the warm air-fuel ratio learning value KGHOT is stored in the memory 42.
And the warm air-fuel ratio learning value KGH
OT is set as the air-fuel ratio learning value KG. Here, the cold air-fuel ratio learning value KGCOLD and the warm air-fuel ratio learning value K
Each of the GHOTs is stored in the memory 42 as a value corresponding to a plurality of operating regions divided by the intake pressure PM and the engine speed NE in association with these operating regions.

In the following step 508, an air-fuel ratio feedback correction coefficient FAF is calculated based on the exhaust oxygen concentration signal XOX. FIG. 14 shows an example of a temporal change mode of the air-fuel ratio feedback correction coefficient FAF. As shown in the figure, the air-fuel ratio feedback correction coefficient FAF is changed when the exhaust oxygen concentration signal XOX switches between a state indicating that the air-fuel ratio of the exhaust is rich and a state indicating that the exhaust air is lean (timing t1, t2, t
In 3), the amount is increased or decreased by a certain amount. Then, the amount is gradually increased or decreased until the exhaust oxygen concentration signal XOX is switched again (timing t1 to t2, t2 to t3).

Incidentally, as described above, the exhaust oxygen concentration signal XO
The operation of increasing / decreasing the air-fuel ratio feedback correction coefficient FAF by a fixed amount at the switching timing of X (skip timing) is called “skip control”. After this skip control, the air-fuel ratio feedback correction coefficient FAF is repeated until the skip timing comes again. The operation of gradually increasing or decreasing is referred to as “integration operation”, which is a well-known control mode in the air-fuel ratio feedback control.

After calculating the air-fuel ratio feedback correction coefficient FAF in this way, it is determined in step 510 whether or not a skip timing is present. If it is determined that it is the skip timing, in step 512, the average value FA of the air-fuel ratio feedback correction coefficient FAF is determined.
It is determined whether the FAV is stable and the change is within a predetermined fluctuation range. For example, when the operating state of the engine 10 is in a steady state, the average value F
Since the amount of fluctuation of AFAV becomes small, this step 51
In 2, it is determined that the average value FAFAV is stable.

If it is determined in step 512 that the average value FAFAV of the air-fuel ratio feedback correction coefficient FAF is stable, the process proceeds to step 514 shown in FIG. 13, and the learning value KG of the air-fuel ratio is calculated by the following equation (2). Calculated based on

KG = FAFAV−1.0 (2) When the air-fuel ratio of the engine 10 tends to be leaner than the stoichiometric air-fuel ratio in a steady operation state, the air-fuel ratio feedback correction coefficient FAF Average value of FAFAV
Is larger than "1.0", the air-fuel ratio learning value KG
Is set as a positive value, and when the air-fuel ratio tends to deviate from the stoichiometric air-fuel ratio to the rich side, the average value FAFAV
Is smaller than “1.0”, the air-fuel ratio learning value KG
Will be set as a negative value.

Then, it is determined in step 516 whether or not the injection timing retarding process is being executed again. If the process is being executed, in step 518, the air-fuel ratio learning value KG is set to the intake pressure PM. And the cold air-fuel ratio learning value K corresponding to the current operating region determined by the engine speed NE and the engine speed NE
Store as GCOLD. On the other hand, if it is determined in step 516 that the injection timing retarding process has not been executed, in step 517, the air-fuel ratio learning value KG is stored as the warm-time air-fuel ratio learning value KGHOT corresponding to the current operation region.

After executing the processes of steps 517 and 518, or when making a negative determination in steps 502, 510 and 512, the ECU 40 once ends the process of this routine. The air-fuel ratio learning value KG learned in this manner is calculated by the fuel injection time TAU as shown in the above equation (1).
This is reflected when calculating.

As described above, in the present embodiment, the air-fuel ratio learning value KG in the air-fuel ratio feedback control is calculated as follows.
The value used during the stop of the injection timing retarding process, that is, the learning value KGHOT during the warm air-fuel ratio, and the value used during the execution of the process, that is, the learning value KGCOLD during the cold process, are learned separately. I have.

Therefore, during execution of the injection timing retarding process,
The fuel injection is executed based on the basic fuel injection amount QINJB, which is increased from that during the stop of the process, by the air-fuel ratio learning value KG corresponding to the degree of the lean deviation of the air-fuel ratio generated by the execution of the process. Become so.

For example, if the air-fuel ratio learning value KG is not separately learned, the air-fuel ratio learning value KG is set so as to suppress the aforementioned lean deviation of the air-fuel ratio during the execution of the injection timing delay processing. Is learned, then
If the air-fuel ratio learning value KG is updated while the injection timing retarding process is stopped, when the injection timing retarding process is executed again, such as during a cold restart, the air-fuel ratio learning value KG is updated based on the updated air-fuel ratio learning value KG. The air-fuel ratio control will be executed. Therefore, while the air-fuel ratio feedback control is stopped,
It is no longer possible to eliminate the lean deviation of the air-fuel ratio, and the feedback control is started, and the basic fuel injection amount QINJ is determined by the air-fuel ratio feedback correction coefficient FAF.
Even if B is increased, the occurrence of a lean deviation immediately after the start of the feedback control is unavoidable, and this cannot be promptly compensated.

In this regard, according to the present embodiment, (5) When the injection timing retarding process is executed during a cold restart, etc., the previous injection timing retarding process is executed as the air-fuel ratio learning value KG. Learning value KGCO learned during cold
Since the LD is read, the lean deviation of the air-fuel ratio accompanying the execution of the process can be promptly compensated, and the decrease or fluctuation of the engine output due to the deviation of the air-fuel ratio can be suppressed at an earlier stage. Become like

[Sixth Embodiment] Next, a sixth embodiment of the present invention will be described focusing on differences from the third embodiment. The description of the same configuration as that of the third embodiment is omitted.

In the present embodiment, both the "fuel injection timing control routine" and the "fuel injection amount control routine" shown in FIGS. 6 and 8 are executed, and depending on whether or not the injection timing delay processing is executed. By controlling the opening of the SCV 34, the intensity of swirl formed in the combustion chamber 16 is adjusted.

The control of the opening of the SCV 34 will be described below with reference to FIGS. FIG. 15 is a flowchart showing the processing content of the "SCV opening control routine", and the ECU 40 repeatedly executes this routine as interrupt processing of a predetermined crank angle cycle.

First, at step 700, the intake pressure P
The basic command opening SCVREQB of the SCV 34 is calculated based on M and the engine speed NE. Next, step 702
, The closing amount DSCV is calculated based on the cooling water temperature THW and the engine speed NE. This confinement amount DSCV is S
This is for reducing the opening of the CV 34 from the basic instruction opening SCVREQB, and the swirl intensity increases as the closing amount DSCV is set to be larger.

The cooling water temperature TH is stored in the memory 42 of the ECU 40.
Function data that defines the relationship between W and the engine speed NE and the closing amount DSCV is stored, and the ECU 40 refers to the function data when calculating the closing amount DSCV. For example, as shown in FIG. 16, the closing amount DSCV is set to be larger as the cooling water temperature THW decreases. The reason why the closing amount DSCV is set in this manner is that the lower the cooling water temperature THW, in other words, the lower the engine temperature, the lower the atomization of the injected fuel and the more difficult it becomes to mix with the intake air.
This is because it is necessary to promote the atomization of the injected fuel by increasing the intensity of the swirl. Further, the closing amount DSCV is set to be larger as the engine speed NE decreases. This is because when the engine speed NE decreases, the speed of introducing the intake air into the combustion chamber 16 decreases, and the swirl intensity also decreases. Therefore, it is necessary to compensate for such a decrease in the swirl intensity.

Next, at step 704, it is determined whether or not the injection timing delay processing is being executed based on the delay processing execution flag XCOLD. If it is determined that the process is being performed, in step 705, a closing amount correction coefficient KS is calculated based on the basic fuel injection amount QINJB (or the intake pressure PM) and the retard amount △ AINJ.

The closing amount correction coefficient KS is for increasing and correcting the swirl intensity in accordance with the degree of decrease in the atomization of the injected fuel due to the execution of the injection timing retarding process.

The memory 42 of the ECU 40 stores the basic fuel injection amount QINJB (or intake pressure PM) and the retard amount △ AI
Function data that defines the relationship between NJ and the confinement correction coefficient KS is stored. FIG. 17 is a graph showing the function data.

As shown in the figure, the larger the retard amount △ AINJ, the larger the closing amount correction coefficient KS is set.
The reason why the closing amount correction coefficient KS is set in this way is as follows.

That is, as the retard amount △ AINJ increases, the distance between the injector 26 and the top surface of the piston 14 when injecting the fuel increases, so that the injected fuel is less likely to be atomized by the heat of the top surface. At the same time, as described above, the amount of fuel adhering to the inner peripheral wall surface of the cylinder 13 also increases. Therefore, a stronger swirl is applied to the combustion chamber 1
This is because it is necessary to promote the atomization of the injected fuel and to suppress the adhesion of the fuel to the inner peripheral wall surface of the cylinder 13 by forming it in the inside.

Further, the closing amount correction coefficient KS is set to be larger as the basic fuel injection amount QINJB increases (or the intake pressure PM increases). This is the basic fuel injection amount QIN
This is because, as the JB increases, the ratio of the injected fuel adhering to the inner peripheral wall surface of the cylinder 13 increases, and the amount of the fuel spray having a low atomization degree (large particle diameter) existing in the cylinder 13 increases. .

After calculating the closing amount correction coefficient KS as described above, in step 706, the current closing amount DS
CV is multiplied by a confinement correction coefficient KS, and the multiplied value (DS
CV × KS) is set as a new closing amount DSCV.

After executing the processing of step 706, or when it is determined in step 704 that the injection timing delay processing has been stopped, the processing shifts to step 708, and the commanded opening degree SCVREQ of the SCV 34 is calculated by the following equation (3). ).

SCVREQ = SCVREQB-DSCV (3) After executing the processing of step 708, the ECU 40 once ends the processing of this routine. The ECU 40 performs feedback control of the motor 35 so that the calculated opening SCVREQ calculated in this way and the actual opening SCVP of the SCV 34 match.

As described above, in the present embodiment, when the injection timing retarding process is executed, the closing amount DSCV
Is increased to decrease the opening of the SCV 34. Therefore, according to the present embodiment, in addition to the same operation and effect as (3) described in the third embodiment, the following operation and effect can be further obtained.

(6) A decrease in the degree of atomization of the injected fuel due to the injection timing retarding process can be suppressed by increasing the swirl intensity. As a result, it is possible to suppress a decrease or fluctuation of the engine output due to combustion being performed with insufficient mixing of the injected fuel and the intake air without atomization being promoted, and to improve fuel efficiency and exhaust properties. Deterioration can be suppressed.

(7) As the retard amount ＤAINJ increases, the closing amount DSC increases.
Since the swirl intensity is increased by correcting so as to increase V, it is possible to more reliably suppress the above-described decrease and fluctuation of the engine output, and the deterioration of the fuel consumption and the exhaust properties. .

(8) The increase in swirl strength makes it difficult for the injected fuel to adhere to the inner peripheral wall surface of the cylinder 13, so that the occurrence of oil dilution due to such fuel adhesion can be suppressed.

[Seventh Embodiment] Next, a seventh embodiment of the present invention will be described, focusing on differences from the third embodiment. The description of the same configuration as that of the third embodiment is omitted.

In the present embodiment, both the “fuel injection timing control routine” and the “fuel injection amount control routine” shown in FIGS. 6 and 8 are executed, and the knock learning value AGKNK in the ignition timing control is used for the injection timing delay processing. Learning is performed as different values during execution and when the processing is stopped.

Hereinafter, each process of the "ignition timing control routine" in which the learning of the knock learning value AGKNK is performed will be described with reference to the flowcharts of FIGS. The ECU 40 repeatedly executes the “ignition timing control routine” as an interruption process of a predetermined crank angle cycle.

First, at step 800 shown in FIG. 18, the basic ignition timing ABSE and the maximum retard value AKMAX are calculated based on the intake pressure PM and the engine speed NE. Here, the maximum retardation value AKMAX is the maximum amount when retarding the basic ignition timing ABSE, and is set to a value that can reliably suppress the occurrence of knocking.

Next, at step 802, it is determined whether or not the injection timing retarding process is being executed based on the retarding process execution flag XCOLD. If it is determined that the injection timing retarding process is being executed, in step 804, the cold knock learning value AGKNKCOLD is stored in the memory 4.
2 and the cold knock learning value AG
KNKCOLD is set as knock learning value AGKNK.

On the other hand, if it is determined in step 802 that the injection timing retarding process has not been executed, then in step 805, the warm knock learning value AGKNKHOT is determined.
Is read from the memory 42, and the warm knock learning value AGKNKHOT is set as the knock learning value AGKNK.

Next, in step 806 shown in FIG. 19, it is determined whether or not knocking has occurred in engine 10 based on knocking signal KCS. If it is determined that knocking has occurred, step 808 is executed.
At a predetermined angle α1
Is added, and the added value (AKCS + α1) is set as a new knock control value AKCS. This knock control value A
KCS is a value whose magnitude changes according to the current knocking state of the engine 10.

On the other hand, if it is determined in step 806 that knocking has not occurred, in step 809, a predetermined angle α2 is subtracted from the current knock control value AKCS, and the difference (AKCS-α2) is used as a new knock control. Set as value AKCS.

After executing the processing in step 808 or step 809, in step 810, a knock retard reflection value AKNK is calculated based on the following equation (4). AKNK = AKMAX−AGKNK + AKCS (4) Next, in step 812, knock control value AKCS
And a predetermined angle β1. Here, knock control value AK
If it is determined that CS is larger than the predetermined angle β1, in step 816, the predetermined angle γ is subtracted from the current knock learning value AGKNK, and the subtraction value (AGKNK−γ) is set as a new knock learning value AGKNK.

On the other hand, if it is determined in step 812 that knock control value AKCS is equal to or smaller than predetermined angle β1,
In step 814, knock control value AKCS is compared with a predetermined angle β2. Here, knock control value AKCS
Is smaller than the predetermined angle β2, Step 8
At 17, a predetermined angle γ is added to the current knock learning value AGKNK, and the added value (AGKNK + γ) is set as a new knock learning value AGKNK.

The knock learning value AGKNK is determined by the engine 1
This indicates a steady tendency of knocking occurring at 0. If the knocking tends to occur frequently by the processing of this routine, it is learned to a relatively small value. When the number is small, the learning is performed to a relatively large value.

Therefore, the knock learning value AGKNK is
In addition to the tendency of knocking according to the octane number of the fuel,
For example, if the leaning tendency of the air-fuel mixture around the spark plug 24 changes due to the execution of the injection timing retarding process, a value that reflects the knocking occurrence tendency corresponding to the change is learned.

For example, during execution of the injection timing retarding process, the air-fuel ratio of the air-fuel mixture around the ignition plug 24 becomes relatively lean, so that the combustion of the air-fuel mixture in the combustion chamber 16 becomes slow and knocking occurs. It becomes difficult to occur, and the generation time of the maximum combustion pressure is relatively delayed. For this reason,
Knock learning value AGKNK is updated so as to be relatively large, and the ignition timing (final ignition timing AOP) is set to an advanced timing by updating knock learning value AGKNK.

On the other hand, when the injection timing retarding process is stopped, the combustion speed of the air-fuel mixture increases, knocking easily occurs, and the generation timing of the maximum combustion pressure is relatively advanced. Therefore, knock learning value AGKN
K is updated so as to be relatively small, and the ignition timing is set to the retard side by updating the knock learning value AGKNK.

After executing the processing of step 816 or step 817, or if a negative determination is made in step 814, it is determined in step 818 whether or not the injection timing retarding processing is being executed. In step 820, the knock learning value AG
KNK is stored in the memory 42 as the cold knock learning value AGKNKCOLD. On the other hand, if it is determined in step 818 that the injection timing retarding process has been stopped, in step 821, the knock learning value AGKNK
Is stored in memory 4 as knock learning value AGKNKHOT during warming.
Stored in 2.

After the knock learning value AGKNK is individually learned and stored in the memory 42 in accordance with whether or not the injection timing retarding process is being executed, in step 822, the knock learning value AGKNK is calculated from the basic ignition timing ABSE. Delay reflection value AK
After subtracting NK and setting the subtraction value (ABS-AKNK) as the final ignition timing AOP, the processing of this routine is temporarily terminated.

As described above, the knock learning value AGKNK in the ignition timing control is set to a value used when the injection timing retarding process is stopped, that is, the warm knock learning value AGKNKHOT, and the knocking learning value AGKNKHOT is being executed. , That is, the knocking learning value AGKNKCOLD during cold learning.

For example, the knock learning value AGKN
If K is not separately learned, even if knock learning value AGKNK is learned during execution of injection timing delay processing, knock learning value AGKNK is updated when injection timing delay processing is stopped thereafter. When it is done,
When the injection timing retarding process is executed again, the ignition timing control is executed based on the updated knock learning value AGKNK.

On the other hand, according to the present embodiment, (9) when the injection timing delay processing is executed at the time of a cold restart or the like, the execution of the previous injection timing delay processing is made as the knock learning value AGKNK. Knock learning value A learned during cold
Since GKNKCOLD is read, it is possible to quickly suppress the generation timing of the maximum combustion pressure from being delayed from a timing suitable for securing the engine output with the execution of the processing, thereby ensuring a good combustion state. . Therefore, it is possible to suppress the decrease or fluctuation of the engine output and the deterioration of the fuel efficiency due to the delay of the generation timing of the maximum combustion pressure earlier.

Further, in the present embodiment, since both the "fuel injection timing control routine" and the "fuel injection amount control routine" shown in FIGS. 6 and 8 are executed, the third embodiment is described. The same operation and effect as the above (3) can be obtained.

[Eighth Embodiment] Next, an eighth embodiment of the present invention will be described, focusing on differences from the third embodiment. The description of the same configuration as that of the third embodiment is omitted.

In the present embodiment, the "fuel injection timing control routine" shown in FIG. 6 is executed, and when the basic fuel injection amount QINJB is increased during the injection timing delay processing, the feedback control of the air-fuel ratio is temporarily performed. I try to stop.

Hereinafter, the fuel injection amount control of this embodiment will be described with reference to the flowchart of FIG. EC
U40 repeatedly executes the "fuel injection amount control routine" shown in the figure as interruption processing of a predetermined crank angle cycle.
In the "fuel injection amount control routine", the steps denoted by the same reference numerals as those in FIG. 8 execute the same processes as those in FIG.

If the ECU 40 determines in step 210 that the retard processing execution flag XCOLD is "1", then in step 222 the basic fuel injection amount QINJ
An injection amount increase coefficient KQ is calculated based on B and the retard amount △ AINJ.

Here, in the third embodiment,
The injection amount increase coefficient K is set so that the air-fuel ratio can be prevented from deviating from the stoichiometric air-fuel ratio to the lean side due to the injection timing delay processing.
However, in the present embodiment, when the retard amount △ AINJ is particularly large, and thus the change in the engine combustion state due to the injection timing retarding process is large, the air-fuel ratio is further higher than the stoichiometric air-fuel ratio. The injection amount increase coefficient KQ is calculated so as to be rich. By setting the air-fuel ratio to be richer than the stoichiometric air-fuel ratio in this way, the combustion state of the engine can be stabilized.

After calculating the injection amount increase coefficient KQ in this way, the ECU 40 changes the air-fuel ratio feedback correction coefficient FAF to "1.0" in step 235.
Then, after executing the process of step 240, the ECU 40 once ends the process of this routine.

As described above, in the present embodiment, when the basic fuel injection amount QINJB is increased based on the injection amount increase coefficient KQ during the injection timing delay processing, the feedback control of the air-fuel ratio is stopped, The control mode of the fuel ratio is switched to open loop control.

Therefore, according to the present embodiment, in addition to the same effect as (3) described in the third embodiment, (10) the basic fuel based on the injection amount increase coefficient KQ can be obtained. Injection amount Q
The INJB increasing operation is performed by the air-fuel ratio feedback correction coefficient F.
Since it will not be canceled by AF,
By setting the air-fuel ratio to be richer than the stoichiometric air-fuel ratio during the injection timing retarding process, it is possible to reliably stabilize the engine combustion state.

[Ninth Embodiment] Next, a ninth embodiment of the present invention will be described, focusing on differences from the third embodiment. The description of the same configuration as that of the third embodiment is omitted.

In this embodiment, the "fuel injection timing control routine", "fuel injection amount control routine", "ignition timing calculation routine", and "SCV opening degree control routine" shown in FIGS. Is done. Further, in this embodiment, in addition to these controls, the target throttle opening TATRG, which is the target control amount of the throttle opening TA, is set larger when the injection timing retarding process is executed than when the same process is not executed. ing.

The procedure for executing the throttle opening control will be described below with reference to FIG. The ECU 40 repeatedly executes a “throttle opening control routine” shown in the figure as an interruption process of a predetermined crank angle cycle.

First, in step 900, the ECU 40 determines whether or not the retard processing execution flag XCOLD is set to "1". Here, when it is determined that the retarding process execution flag XCOLD is not “1”, that is, when it is determined that the injection timing retarding process is not being performed, in step 915, the accelerator opening degree ACCP and the engine speed NE are set. The target throttle opening TATRG is calculated based on the target throttle opening.

On the other hand, if it is determined in step 900 that the delay processing execution flag XCOLD is "1", that is, if it is determined that the injection timing delay processing is being executed,
In step 910, the CU 40 calculates a target throttle opening TATRG corresponding to the execution of the injection timing retarding process, based on the accelerator opening ACCP and the engine speed NE.

The memory 42 of the ECU 40 stores function data defining the relationship between the target throttle opening degree TATRG, the accelerator opening degree ACCP, and the engine speed NE. Function data corresponding to non-execution time is stored separately for each. The ECU 40 calculates the target throttle opening degree TATRG with reference to the former function data in the process of step 910 and the latter function data in the process of step 915.

Here, the above function data is obtained if both the accelerator opening ACCP and the engine speed NE are the same.
The target throttle opening TATRG calculated based on the processing of step 910 is set to be larger than the target throttle opening TATRG calculated based on the processing of step 915.

Therefore, when the injection timing retarding process is performed, the throttle opening TA is set to be larger than when the process is not performed, so that the pumping loss is reduced. Further, the throttle opening T
Since the intake pressure PM increases in accordance with the setting of A, the basic fuel injection amount QINJB is also set to be relatively large by an amount corresponding to the increase in the throttle opening TA.

Thus, step 910 or step 9
After calculating the target throttle opening degree TATRG in step 15, the ECU 40 determines in step 920 the throttle opening degree TATRG.
Is controlled to match the target throttle opening TATRG, and the processing of this routine is temporarily ended.

In the present embodiment, the fuel injection amount, the ignition timing, and the SCV opening are controlled by executing the “fuel injection amount control routine”, the “ignition timing calculation routine”, and the “SCV opening control routine”. Since it is changed so as to be compatible with the injection timing delay processing, the same operation and effect as (3), (4), (6) to (8) described in the third, fourth, and sixth embodiments are obtained. Can play.

Here, when the fuel injection amount, the ignition timing, and the SCV opening are changed so as to conform to the injection timing retarding process as described above, the deterioration of the engine combustion state is reliably suppressed. Although it is possible to reduce the engine output due to the change of the fuel injection amount, the ignition timing, and the SCV opening degree, when the injection timing retarding process shifts from the execution to the non-execution, There is a tendency for torque shock to occur.

In this regard, according to the present embodiment, (11) the throttle opening TA is set to be relatively large at the time of executing the injection timing retarding process. As a result, the pumping loss can be reduced. As a result, a decrease in engine output due to execution of the injection timing retarding process is suppressed as much as possible,
The occurrence of the torque shock as described above can be suppressed.

Each of the embodiments described above can be implemented by changing the configuration as follows. In the second, seventh, and sixth embodiments, the injection timing is advanced or the swirl intensity is increased in addition to the increase in the fuel injection amount when the injection timing retarding process is performed. A configuration in which only the ignition timing or the swirl intensity is changed at the time of executing the timing delay processing may be adopted. Further, it is also possible to adopt a configuration in which both the ignition timing and the swirl intensity are changed when the injection timing retarding process is executed, and further, the fuel injection amount, the ignition timing, and the swirl intensity are all changed.

In the seventh embodiment, the knock learning value AGKNK is learned as a separate value depending on whether or not the injection timing retarding process is executed.
For example, it is also possible to adopt a configuration in which the maximum retard value AKMAX is separately set according to whether or not the injection timing retard process is being executed.

In the fifth embodiment, the air-fuel ratio learning value KG is set according to whether or not the injection timing retarding process is executed, and the fuel injection time TAU is calculated based on the air-fuel ratio learning value KG. The fuel injection time TA
The correction coefficient for correcting U is determined by such an air-fuel ratio learning value K.
G may be defined separately, and the value of the correction coefficient may be separately set to a value when the injection timing delay processing is being executed and a value when the injection timing is stopped.

In the eighth embodiment, the basic fuel injection amount QINJB is increased and corrected based on the injection amount increase coefficient KQ. However, similar to the first embodiment, when the basic fuel injection amount QINJB is cold. By setting the same basic injection quantity QINJBCOLD, the same basic fuel injection quantity QINJ
B may be increased and corrected.

In the ninth embodiment, the “fuel injection amount control routine”, “ignition timing calculation routine”,
Although the "SCV opening control routine" is all executed, one or two of these processes may be selected and executed.

In the ninth embodiment, each function data corresponding to the execution time and the non-execution time of the injection timing retarding process is represented by E
The target throttle opening TATRG is stored in the memory 42 of the CU 40 and is calculated based on the function data corresponding to the value of the retard processing execution flag XCOLD.
For example, the target throttle opening TATRG is calculated in advance based on the accelerator opening ACCP and the engine speed NE, and the injection timing retarding process is executed (the retarding process execution flag X
(When it is determined that COLD is “1”), the target throttle opening TATRG may be increased and corrected.

At this time, the target throttle opening TAT
The rate of increase correction of RG may be variably set based on the retard amount △ AINJ of the fuel injection timing AINJ. With this configuration, the target throttle opening TATRG can be increased and corrected by an amount corresponding to the decrease in the engine output due to the execution of the injection timing delay processing, and the occurrence of torque shock can be more reliably suppressed. become able to.

In the ninth embodiment, the feedback control of the air-fuel ratio is stopped when the basic fuel injection amount QINJB is increased and corrected by executing the injection timing retarding process. Further, when the engine is started or when the cooling water temperature of the engine 10 is low, the basic fuel injection amount Q
Similarly, the feedback control of the air-fuel ratio may be stopped when the INJB is increased.

In the above embodiments, the fuel injection amount, the ignition timing, and the swirl intensity are corrected in conjunction with the execution of the injection timing retarding process. In addition to these various control amounts, for example, the fuel injection pressure and the throttle A mechanism for adjusting the opening degree of the valve 38 or adjusting the opening / closing timing and the lift amount of the intake valve 20 and the exhaust valve 22 is provided.
The adjustment amount by this mechanism may be corrected.

In each of the above embodiments, the cooling water temperature THW is selected as the engine temperature, and it is determined whether or not the engine is in an operating state in which fuel adheres to the ignition plug 24 based on the cooling water temperature THW. For example, the cooling water temperature T
Instead of the HW, such an operation state can be determined based on a lubricating oil temperature, an intake air temperature, an elapsed time after starting the engine 10, an accumulated fuel injection amount, and the like.

In the above embodiments, when the fuel injection timing AINJ is retarded when the engine is cold, the timing is set to the intake stroke. However, the timing may be further retarded to the first half of the compression stroke. .

In each of the above embodiments, the combustion mode is stratified combustion,
Although the control device of the engine 10 that switches between weak stratified charge combustion and homogeneous combustion is applied, the control device according to the present invention may be applied to an engine that executes only homogeneous combustion.

[0192]

According to the first to sixth aspects of the present invention, the change of the engine combustion state due to the change of the fuel injection timing is suppressed, and even if the fuel injection timing is retarded when the engine is cold, the engine temperature is kept low. It is possible to maintain a favorable engine combustion state substantially equal to the time.

Particularly, according to the second aspect of the present invention,
When suppressing the fuel adhesion to the spark plug by retarding the fuel injection timing, it is necessary to minimize the amount of retardation and suppress the change in the engine combustion state due to the retardation of the fuel injection timing. Thus, it is possible to set a more appropriate change rate of the control amount. As a result, a favorable engine combustion state can be reliably maintained.

According to the third aspect of the present invention,
By increasing the fuel injection amount, it is possible to suppress the leaning of the air-fuel ratio due to the change of the fuel injection timing, and it is possible to suppress the decrease and fluctuation of the engine output due to the leaning of the air-fuel ratio. In particular, if the increase rate of the fuel injection amount is increased as the retard amount of the fuel injection timing increases, a more appropriate increase rate will be set,
The engine output can be reliably suppressed from decreasing or fluctuating.

Further, according to the invention described in claim 4,
A change in the timing of occurrence of the maximum combustion pressure to a timing on the retard side due to a change in the fuel injection timing can be suppressed by advancing the ignition timing. It is possible to suppress a decrease or fluctuation in engine output and a deterioration in fuel efficiency due to a shift to a more retarded timing. In particular, if the advance amount of the ignition timing is increased as the retard amount of the fuel injection timing increases, a more appropriate advance amount of the ignition timing will be set.
It is possible to reliably suppress such a decrease or fluctuation of the engine output and deterioration of the fuel efficiency.

According to the fifth aspect of the present invention, it is possible to suppress a change in the combustion state due to a decrease in the degree of atomization of the injected fuel due to a change in the fuel injection timing by increasing the swirl intensity. It is possible to suppress a decrease or fluctuation in engine output due to combustion being performed with insufficient mixing of the injected fuel and the intake air without atomization being promoted, as well as deterioration of fuel consumption and exhaust properties. Become like In particular, if the rate of increase in swirl intensity is increased as the amount of retard of the fuel injection timing increases, a more appropriate rate of increase will be set, and such a decrease or fluctuation in engine output, deterioration of fuel efficiency and exhaust properties will occur. Can be reliably suppressed.

Further, according to the invention described in claim 6,
The pumping loss when the engine is cold is reduced as compared to when the engine is warm, and the engine output when the engine is cold is increased. As a result, it is possible to reduce the difference in engine output between when the engine is cold and when the engine is warm, and it is possible to suppress the occurrence of torque shock during the transition from the time when the engine is cold to the time when the engine is warm. become able to.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an engine control device.

FIG. 2 is a sectional view showing shapes of an intake port and an exhaust port.

FIG. 3 is a flowchart showing an execution procedure of fuel injection timing control.

FIG. 4 is a flowchart showing an execution procedure of fuel injection amount control.

FIG. 5 is a flowchart showing a procedure for calculating an ignition timing.

FIG. 6 is a flowchart showing an execution procedure of fuel injection timing control.

FIG. 7 is a graph showing a relationship between a cooling water temperature and a cold injection timing.

FIG. 8 is a flowchart showing a procedure for executing fuel injection amount control.

FIG. 9 is a graph showing a relationship between a basic fuel injection amount, a retard amount, and an injection amount increase coefficient.

FIG. 10 is a flowchart showing a procedure for calculating an ignition timing.

FIG. 11 is a graph showing a relationship between a basic fuel injection amount, a retard amount, and an ignition timing advance amount.

FIG. 12 is a flowchart showing an execution procedure of air-fuel ratio control.

FIG. 13 is a flowchart illustrating an execution procedure of air-fuel ratio control.

FIG. 14 is a timing chart showing an example of a change mode of an air-fuel ratio feedback correction coefficient.

FIG. 15 is a flowchart illustrating an execution procedure of SCV opening control;

FIG. 16 is a graph showing the relationship between the cooling water temperature and the amount of confinement.

FIG. 17 is a graph showing a relationship between a basic fuel injection amount, a retard amount, and a closing amount correction coefficient.

FIG. 18 is a flowchart showing a procedure for calculating an ignition timing.

FIG. 19 is a flowchart showing a procedure for calculating an ignition timing.

FIG. 20 is a flowchart showing a procedure for executing fuel injection amount control.

FIG. 21 is a flowchart showing an execution procedure of throttle opening control.

[Explanation of symbols]

10 engine, 11 cylinder head, 12 cylinder block, 13 cylinder, 14 piston, 14a
... recess, 16 ... combustion chamber, 20 ... intake valve, 22 ... exhaust valve, 24 ... spark plug, 25 ... igniter, 26 ...
Injector, 30 ... intake passage, 30a, 30b ... intake port, 32 ... exhaust passage, 32a, 32b ... exhaust port, 33 ... purge amount control valve, 34 ... SCV, 35 ... motor, 36 ... surge tank, 37 ... purge passage , 38: Throttle valve, 39: Throttle motor, 40: EC
U, 42: memory, 51: crank angle sensor, 52: cam angle sensor, 53: intake pressure sensor, 54: accelerator sensor, 55: SCV opening degree sensor, 56: water temperature sensor, 57
... knock sensor, 58 ... oxygen sensor, 60 ... accelerator pedal.

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat II (Reference) F02D 43/00 301 F02D 43/00 301J 45/00 312 45/00 312Q 368 368T F02P 5/15 F02P 5/15 E ( 72) Inventor Katsushi Hashizume 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation (72) Inventor Koichi Yonezawa 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation F Term (reference) 3G022 AA07 AA08 BA01 CA01 CA02 DA01 EA07 FA06 GA01 GA02 GA05 GA07 GA08 GA09 GA13 3G084 AA04 BA05 BA09 BA13 BA15 BA17 BA21 BA27 CA01 CA02 DA02 DA10 DA11 EA07 EA11 EB11 EB16 EB18 EC02 EC03 FA00 FA10 FA11 FA20 FA25 FA29 FA33 HA18 HA14 HA14 HA14 KA01 KA05 LA00 LA01 LA05 LA07 LB04 LC03 MA01 MA13 MA19 NA03 NA04 NA08 ND01 ND15 ND21 ND22 ND33 NE11 NE12 NE13 NE14 NE15 NE23 PA00Z PA07Z PA11A PB09Z PC08Z PD03A PE01Z PE03Z PE04Z PE08Z PF03Z

Claims (6)

[Claims] The present invention is applied to a spark ignition type internal combustion engine in which fuel is directly injected into a cylinder, and the fuel injection timing set in the first half of the intake stroke when the engine is warm is set to a retarded timing when the engine is cold. In the control device for an internal combustion engine having a fuel injection timing changing means for changing, the control amount of the internal combustion engine which affects the engine combustion state in order to suppress a change in the engine combustion state accompanying the change in the fuel injection timing is set to the control amount. A control device for an internal combustion engine, comprising: a control amount changing unit that changes between an engine warm state and the engine cold state. 2. The control device for an internal combustion engine according to claim 1, wherein the fuel injection timing changing means sets the fuel injection timing retard amount to be larger as the engine temperature decreases. Is a control device for setting the change rate of the control amount to be larger as the retard amount increases. 3. The control device for an internal combustion engine according to claim 1, wherein the control amount changing means controls the engine cold state so as to suppress an air-fuel ratio from becoming lean with a change in the fuel injection timing. A control device for an internal combustion engine, wherein the fuel injection amount of the internal combustion engine is sometimes increased from the fuel injection amount during the engine warm state. 4. The control device for an internal combustion engine according to claim 1, wherein said control amount changing means suppresses a delay in a generation timing of a maximum combustion pressure due to a change in said fuel injection timing. A control device for an internal combustion engine, wherein the ignition timing of the internal combustion engine is advanced more than the ignition timing of the internal combustion engine when the engine is cold. 5. The control device for an internal combustion engine according to claim 1, wherein the control amount changing means is configured to suppress a decrease in atomization degree of the injected fuel due to a change in the fuel injection timing. A control device for an internal combustion engine, wherein the intensity of swirl generated in the cylinder when the engine is cold is increased more than the intensity when the engine is warm. 6. The control device for an internal combustion engine according to claim 3, wherein said control amount changing means further increases the throttle opening when said engine is cold than the opening when said engine is hot. A control device for an internal combustion engine, wherein