JP2000199447A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent inconveniences such as damage of a catalyst, generation of impact and lowered drivability when control returns to normal control from combustion stabilization control which improves combustion stability. SOLUTION: If a predetermined time A or more passes (step 150) after feedback control of an air-fuel ratio is started and load LS of an internal combustion engine equals to or is less than a predetermined value B (step 152), combustion stabilization control is returned to normal control by setting a control switch flag F to '0' (step 154). Combustion stabilization control may be returned to normal control while fuel cut control is being implemented or a vehicle is decelerating.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine, and more particularly to a control device for an internal combustion engine having a function of executing combustion stabilization control for improving flammability as compared with normal control.

[0002]

2. Description of the Related Art During normal operation of an internal combustion engine, the air-fuel ratio is controlled to a lean side in order to reduce emissions. However, at the time of low-temperature operation, since the fuel is not easily vaporized, if the air-fuel ratio is controlled to the lean side, the combustion state becomes unstable and drivability is deteriorated. Therefore, conventionally, during low-temperature operation, intake-synchronous injection control that performs fuel injection during the opening period of the intake valve, injection-amount increase control that increases the fuel injection amount from normal, or ignition timing that is lower than normal. The stabilization of the combustion state is performed by the ignition timing advance control for advancing the ignition timing. Hereinafter, the above-described control executed to stabilize the combustion state during the low-temperature operation is referred to as “combustion stabilization control”.

[0003] By the way, as the fuel for the internal combustion engine, there is a case where a heavy fuel having a property of being less likely to evaporate than a normal fuel (light fuel) is used. Even if such a heavy fuel is used, if the combustion stabilization control is executed under conditions suitable for the heavy fuel so that the combustion stability during low-temperature operation can be ensured, when light fuel is used, As a result, the emission in the exhaust gas increases. Therefore, for example, in the control device for an internal combustion engine disclosed in Japanese Patent Application Laid-Open No. 9-206855, the property of the fuel is detected based on the combustion state of the internal combustion engine, and the combustion stabilization control is executed according to the result. And

[0004]

By the way, during the execution of the combustion stabilization control, the emission increases compared to during the normal control. For this reason, it is necessary to return from the combustion stabilization control to the normal control when the engine is warmed up after the start of the internal combustion engine. When returning from the combustion stabilization control to the normal control, an impact is generated due to discontinuous changes in the control conditions. Further, when returning from the combustion stabilization control to the normal control, the fuel contained in the exhaust gas decreases (in the case of the intake synchronization control and the fuel increase control), or the ignition timing changes from the advance side to the retard side. (In the case of ignition timing advance control)
The temperature of the catalyst that purifies the exhaust gas rises. Therefore, if the control is returned in a state where the temperature of the catalyst is high, the temperature of the catalyst is excessively increased, and the catalyst is deteriorated. Further, when returning from the fuel stabilization control to the normal control, the drivability may be deteriorated because the combustion state changes to an unstable side. However, the above-described conventional control device does not consider the above-described problem associated with the return from the combustion stabilization control to the normal control.

[0005] The present invention has been made in view of the above points, and provides a control apparatus for an internal combustion engine capable of avoiding the above-mentioned problems associated with returning from the combustion stabilization control to the normal control. With the goal.

[0006]

The above object is achieved by the present invention.
A control device for an internal combustion engine having a function of executing combustion stabilization control for improving combustion stability as compared with normal control, wherein the combustion stabilization is performed at a timing according to an operation state of the internal combustion engine. This is achieved by a control device for an internal combustion engine including a control return means for returning from control to normal control.

In the present invention, the control device for the internal combustion engine is:
It has a function of executing combustion stabilization control for improving combustion stability as compared with the normal control. When returning from the combustion stabilization control to the normal control, inconveniences such as shock due to torque change, drivability deterioration due to instability of the combustion state, and catalyst damage due to temperature rise may be caused. These disadvantages can be avoided depending on the operating state of the internal combustion engine. Therefore, according to the present invention, it is possible to prevent the above-described inconvenience associated with control return by the control return means determining the return timing from the combustion stabilization control to the normal control according to the operating state of the internal combustion engine. it can.

In this case, the control return means may return from the combustion stabilization control to the normal control when the load on the internal combustion engine is equal to or less than a predetermined value. . In the second aspect of the present invention, the temperature of the catalyst becomes low during the low load operation of the internal combustion engine. Therefore, when the load of the internal combustion engine is equal to or less than the predetermined value, the control return unit performs the return from the combustion stabilization control to the normal control. Can be prevented.

The control returning means may return from the combustion stabilization control to the normal control when the vehicle decelerates. According to the third aspect of the invention, at the time of deceleration of the vehicle, even if the combustion state is destabilized, drivability such as rattling does not deteriorate. Therefore, according to the present invention, when the control recovery means performs the return from the combustion stabilization control to the normal control when the vehicle is decelerating, the combustion state becomes unstable with the return of the control. Furthermore, deterioration of drivability can be prevented.

[0010] As described in claim 4, the control return means may return from the combustion stabilization control to the normal control at the time of fuel cut of the internal combustion engine.
According to the fourth aspect of the present invention, no combustion is performed at the time of fuel cut of the internal combustion engine. Therefore, at the time of fuel cut, a change in output torque and instability of the combustion state cannot occur. Therefore, according to the present invention, the control return means performs the return from the combustion stabilization control to the normal control at the time of the fuel cut of the internal combustion engine, thereby reducing the impact accompanying the control return and the instability of the combustion state. Can be prevented.

[0011]

FIG. 1 is a block diagram of a system to which a control device for an internal combustion engine according to a first embodiment of the present invention is applied. The system according to the present embodiment includes an internal combustion engine 10. The internal combustion engine 10 is controlled by the ECU 12. The internal combustion engine includes a cylinder block 14. Inside the cylinder block 14, a cylinder 16 and a water jacket 18 are formed. The water jacket 18 is provided with a water temperature sensor 19. The water temperature sensor 19 outputs a signal corresponding to the temperature of the cooling water flowing inside the water jacket 18 (hereinafter referred to as the water temperature THW) to EC.
Output to U12. The ECU 12 has a water temperature sensor 19
The water temperature THW is detected based on the output signal.

A piston 20 is provided inside the cylinder 16. The piston 20 can slide vertically inside the cylinder 16 in FIG. A cylinder head 22 is fixed to an upper portion of the cylinder block 14. An intake port 24 and an exhaust port 26 are formed in the cylinder head 22. The bottom surface of the cylinder head 22, the upper surface of the piston 20, and the side wall of the cylinder 16 define a combustion chamber. The above-described intake port 24 and exhaust port 26 are both
8 is open. The tip of the ignition plug 30 is exposed in the combustion chamber 28. The ignition plug 30 ignites fuel in the combustion chamber 28 by receiving an ignition signal from the ECU 12.

The internal combustion engine 10 also includes an intake valve 34 and an exhaust valve 36. Openings of the intake port 24 and the exhaust port 26 to the combustion chamber 28 are respectively provided with intake valves 3
4 and a valve seat for the exhaust valve 36 are formed. The intake valve 34 and the exhaust valve 36 are separated from and seated on each valve seat,
The intake port 24 and the exhaust port 26 are opened and closed, respectively.

The intake port 24 has an intake manifold 3
8 are in communication. A fuel injection valve 40 is provided in the intake manifold 38. The fuel injection valve 40 is ECU1
The fuel is injected into the intake manifold 38 in accordance with the command signal given from Step 2. A surge tank 42 communicates with the upstream side of the intake manifold 38. An intake pipe 44 communicates further upstream of the surge tank 42. The intake pipe 44 is provided with a throttle valve 46. In the vicinity of the throttle valve 46, a throttle opening sensor 48 is provided. Throttle opening sensor 4
The output signal of 8 is supplied to the ECU 12. ECU1
2 is based on the output signal of the throttle opening sensor 48,
Detect throttle opening.

An air flow meter 50 communicates upstream of the intake pipe 44. The air flow meter 50 outputs a signal corresponding to the flow rate of the air passing therethrough to the ECU 12. The ECU 12 detects the intake air amount GA of the internal combustion engine 10 based on the output signal of the air flow meter 50. An air cleaner 52 communicates further upstream of the air flow meter 50. The outside air filtered by the air cleaner 52 flows into the intake pipe 44.

On the other hand, an exhaust passage 54 communicates with the exhaust port 26 of the internal combustion engine. An O ₂ sensor 56 is provided in the exhaust passage 54. The O ₂ sensor 56 outputs a signal corresponding to the concentration of oxygen contained in the exhaust gas to the ECU 12. A catalytic converter 58 is provided downstream of the O2 sensor 56 in the exhaust passage 54. The catalytic converter 58 includes a hydrocarbon (HC) contained in the exhaust gas,
Carbon monoxide (CO), and for purifying the exhaust gas by adsorbing the nitrogen oxides (NO _X). Catalytic converter 5
8 is provided with a catalyst temperature sensor 60. The catalyst temperature sensor 60 outputs a signal corresponding to the temperature of the catalytic converter 58 (hereinafter, referred to as a catalyst temperature Tc) to the ECU 12. The ECU 12 detects the catalyst temperature Tc based on the output signal of the catalyst temperature sensor 58.

The internal combustion engine 10 also includes a crank angle sensor 62. The crank angle sensor 62 outputs a pulse signal to the ECU 12 every time the internal combustion engine 10 rotates by a predetermined crank angle. The ECU 12 detects the rotation speed of the internal combustion engine 10 (hereinafter, referred to as engine speed NE) based on the output signal of the crank angle sensor 62. EC
An idle switch 64 and a wheel speed sensor 66 are also connected to U12. Idle switch 64
Is a switch that is turned on when an accelerator operation is being performed and is turned off when the accelerator operation is released. The ECU 12 turns on / off the idle switch 64.
The presence or absence of an accelerator operation is determined based on the off state. The wheel speed sensor 66 outputs a signal corresponding to the wheel speed VW. The ECU 12 estimates the vehicle speed V based on the output signal of the wheel speed sensor 66.

In the system of this embodiment, the internal combustion engine 1
During the normal operation of 0, the air-fuel ratio is controlled to the lean side in order to reduce the emission in the exhaust gas. Hereinafter, the above control realized during the normal operation of the internal combustion engine 10 is referred to as “normal control”. On the other hand, when the combustion state is expected to be unstable, such as when the internal combustion engine 10 is started at a low temperature, the ignition timing is advanced to make the ignition timing more advanced than during normal control in order to ensure combustion stability. Control is executed. However, during execution of the ignition advance control, the emission in the exhaust gas tends to increase, so that it is possible to return from the ignition timing advance control to the normal control at an appropriate timing when the internal combustion engine 10 is warmed up. is necessary.

When returning from the ignition timing advance control to the normal control, the ignition timing changes to the retard side. When the ignition timing changes to the retard side, the time required for the burned gas to be discharged to the exhaust passage 54 after the combustion in the combustion chamber 28 is shortened, so that the temperature of the exhaust gas increases. For this reason, if the return to the normal control is performed under the condition that the temperature of the catalytic converter becomes high, the catalytic converter 58 is overheated,
The catalytic converter 58 may be damaged. The system of the present embodiment is characterized in that the above-described inconvenience can be prevented by returning from the ignition timing advance control to the normal control at an appropriate timing. Hereinafter, FIGS. 2 to 4
With reference to, the contents of the processing executed by the ECU 12 in the present embodiment will be described.

FIG. 2 is a flowchart of a routine executed by the ECU 12 to start the ignition timing advance control in this embodiment. Note that the routine shown in FIG. 2 and each of the following routines are routine interruption routines started at predetermined time intervals. When the routine shown in FIG. 2 is started, first, the process of step 100 is executed.

In step 100, it is determined whether or not the elapsed time T after the start of the internal combustion engine 10 is equal to or less than a predetermined value a. As a result, if T ≦ a is satisfied, it is next determined in step 102 whether or not the water temperature THW is less than a predetermined value b. If THW <b is satisfied in step 102, it is determined that the internal combustion engine 10 is in the low temperature start state. In this case, next in step 104,
After the control switching flag F is set to “1”, the current routine ends.

The ECU 12 sets the control switching flag F to "1".
, The ignition timing advance control is executed. Therefore, according to the above-described processing, the ignition timing advance control is performed at the time of the low temperature start of the internal combustion engine 10, so that good combustion stability in the idling operation state can be obtained. On the other hand, if a negative determination is made in step 100 or 102, then in step 106, the control switching flag F is set to "0". When the process of step 106 is completed, the process proceeds to step 108.

In step 108, it is determined whether or not the intake air amount GA of the internal combustion engine 10 is less than a predetermined value c.
In general, the combustion tends to be unstable as the intake air amount GA is smaller. Therefore, if GA <c is satisfied in step 108, it is determined that combustion may be unstable, and the process of step 110 is performed next. On the other hand, if GA <c is not satisfied in step 108, the current routine ends.

In step 110, it is determined whether or not the elapsed time T after the start of the internal combustion engine 10 is less than a predetermined value d. The predetermined value d is set to a value larger than the predetermined value a. If T <d is satisfied in step 110, the process of step 112 is executed next. on the other hand,
If T <d is not satisfied in step 110, the current routine ends.

In step 112, it is determined whether or not the water temperature THW is lower than a predetermined value e. The predetermined value e is set to a value larger than the predetermined value b. Step 112
If THW <e holds, it is determined that the internal combustion engine 10 has not yet been warmed up.
4 is executed. On the other hand, if THW <e is not satisfied in step 112, the current routine ends.

In step 114, it is determined whether or not the engine speed NE is less than a predetermined value f. As a result, NE
If <f is satisfied, it is determined that the combustion state is unstable, and then in step 116, the control switching flag F is set to "1", so that the ignition timing advance control is executed. . On the other hand, in step 114, NE <f
Is not established, this routine is ended.

As described above, according to the routine shown in FIG. 2, when the intake air amount GA is less than c, the elapsed time T after starting is less than d, and the water temperature THW is less than e, It is determined that the combustion state has been destabilized when the engine speed NE has dropped below the predetermined value f. In this case, the control switching flag F is set to "1" in step 116, and the ignition timing advance control is executed, thereby stabilizing the combustion state.

FIG. 3 is a flowchart of a routine executed by the ECU 12 to return from the ignition timing advance control to the normal control. When the routine shown in FIG. 3 is started, first, the processing of step 150 is executed. In step 150, it is determined whether or not the time counter ecfaf is equal to or more than a predetermined value A. As will be described later, the time counter ecfaf is a counter that is automatically incremented each time a unit time elapses, and represents an elapsed time after feedback control of the air-fuel ratio (hereinafter, referred to as FAF control) is started. FAF control is for the air-fuel ratio to control the amount of fuel injection based on the output signal of the O ₂ sensor 56 to a predetermined target value, after the start of the internal combustion engine 10, O ₂
It starts when the sensor 56 has warmed up and its output signal has stabilized. Immediately after the start of the FAF control, the air-fuel ratio has not yet converged to the target value, and it is not appropriate to return from the ignition timing advance control to the normal control in such an unstable state. Therefore, in step 150, ecfaf ≧ A
Is not established, the current routine is terminated without performing any processing thereafter. On the other hand, if ecfaf ≧ A is satisfied in step 150, the process of step 152 is executed next.

In step 152, it is determined whether the load LS of the internal combustion engine 10 is equal to or less than a predetermined value B. Load L
S is a variable proportional to the intake air amount GA, and is obtained by multiplying the intake air amount GA by a predetermined coefficient corresponding to the stroke volume of the internal combustion engine 10. During low-load operation, the amount of exhaust gas passing through the catalytic converter 58 is small, so that the temperature of the catalytic converter 58 is lower than during high-load operation. Therefore, in step 152, LS ≦
If B is satisfied, it is determined that the catalytic converter 58 will not be damaged even if the temperature of the catalytic converter 58 increases with the return from the ignition timing advance control to the normal control. In this case, next, in step 154, the control switching flag F is set to "0", and then this routine is ended. As described above, the ECU 12 executes the ignition timing advance control when the control switching flag F is “1”. Therefore, according to the processing of step 154,
The return from the ignition timing advance control to the normal control is performed. On the other hand, if LS ≦ B is not established in step 152, the catalytic converter 58 is in a high temperature state, and if the control is returned from the ignition timing advance control to the normal control, the catalytic converter 58 may be damaged by a further temperature rise. It is determined that there is. Therefore, in this case, the current routine ends without operating the control switching flag F.

FIG. 4 is a flowchart of a routine executed by the ECU 12 to count the elapsed time after the start of the FAF control. When the routine shown in FIG. 4 is started, first, the processing of step 160 is executed. Step 16
At 0, it is determined whether or not the FAF start flag exfaf is “0”. The FAF start flag exfaf is a flag that is set to “1” when the above-described FAF control is started. Therefore, in step 160, ex
If faf = 0 is established, it is determined that the FAF control has not been started yet, and then, in step 162, the time counter ecfaf is reset to “0”. On the other hand, if exfaf = 0 is not satisfied, the current routine ends while the value of the time counter ecfaf is maintained. According to the processing of steps 160 and 162, the value of the time counter ecfaf indicates the elapsed time after the start of the FAF control.

As described above, according to the routine shown in FIG. 3, when the internal combustion engine 10 is in a low load operation state, that is, when the catalytic converter 58 is at a low temperature, the ignition timing advance control is changed to the normal control. Return is performed. Therefore, according to the system of the present embodiment, the catalytic converter 58 increases due to the temperature rise accompanying the return from the ignition timing advance control to the normal control.
Can be prevented from being damaged.

Next, second to sixth embodiments of the present invention will be described. The systems of the second to sixth embodiments are realized by executing the routines of FIGS. 5 to 9 in place of the routine of FIG. 3 in the system of the first embodiment. As described above, when the ignition timing advance control is executed, the output torque of the internal combustion engine 10 increases as compared with the time of the normal control by improving the combustion stability. Therefore, when the control is returned from the ignition timing advance control to the normal control, an impact is generated on the vehicle as the output torque changes discontinuously. The systems of the second to sixth embodiments are characterized in that the uncomfortable feeling given to the driver due to the impact can be reduced. Hereinafter, the contents of the processing executed by the ECU 12 in each embodiment will be described with reference to the routines shown in FIGS. Note that FIG.
Steps for performing the same processes as those of the routine shown in FIG.

FIG. 5 shows a second embodiment of the present invention.
4 shows a flowchart of a routine executed by the CU 12.
In the routine shown in FIG. 5, when it is determined in step 152 that the load LS of the internal combustion engine 10 is equal to or smaller than the predetermined value B, the process of step 200 is executed next. In step 200, it is determined whether or not the air conditioner switching flag exacinv is set to "1". The air conditioner switching flag exacinv is a flag that rises to “1” only when the air conditioner mounted on the vehicle is switched from on to off or from off to on. Therefore, if exacinv = 1 is satisfied in step 200, it is determined that the air conditioner is being switched on / off. In this case, in step 154, the control switching flag F is set to "0", thereby returning from the ignition timing advance control to the normal control. On the other hand, if exacinv = 1 is not satisfied in step 200, the current routine is ended without operating the control switching flag F.

As described above, according to the routine shown in FIG. 5, the switching from the ignition timing advance control to the normal control is performed at the same time when the air conditioner is switched on / off. When the air conditioner is switched on / off, an impact is generated on the vehicle accordingly. Therefore, according to the present embodiment, the impact associated with the return from the ignition timing advance control to the normal control is generated simultaneously with the impact associated with the turning on / off of the air conditioner, and the number of impacts is reduced. Feeling of discomfort is reduced.

FIG. 6 shows a third embodiment of the present invention.
5 is a flowchart of a routine executed by the CU 12.
In the routine shown in FIG. 6, when it is determined in step 152 that the load LS of the internal combustion engine 10 is equal to or smaller than the predetermined value B, the process of step 210 is executed next. In step 210, it is determined whether or not the shift switching flag exndrinv is set to "1". The shift switching flag exndrinv is a flag that rises to “1” only when the shift position (N, D, R, etc.) of the shift lever for automatic (AT) transmission of the vehicle is switched. Therefore, when exndrinv = 1 is satisfied in step 210, it is determined that the shift position of the shift lever is being switched. In this case, in step 154, the control switching flag F is set to "0", thereby returning from the ignition timing advance control to the normal control. On the other hand, if it is determined in step 200 that extrandv = 1 is not established, the current routine is terminated without operating the control switching flag F.

As described above, according to the routine shown in FIG. 6, the shift from the ignition timing advance control to the normal control is performed simultaneously with the switching of the shift position of the shift lever. Therefore, according to the present embodiment, the shock accompanying the return from the ignition timing advance control to the normal control is generated at the same time as the shift position is switched, and the number of times of the occurrence of the shock is reduced, thereby reducing the uncomfortable feeling for the driver. Is done.

FIG. 7 shows a fourth embodiment of the present invention.
5 is a flowchart of a routine executed by the CU 12.
In the routine shown in FIG. 7, when it is determined in step 152 that the load LS of the internal combustion engine 10 is equal to or smaller than the predetermined value B, the process of step 220 is executed next. In step 220, the electric load switching flag exelsinv
Is set to "1". The electric load switching flag exelsinv indicates that an electric device (e.g., a light) mounted on the vehicle changes from on to off, or
It is a flag that rises to “1” only when switching from off to on. Therefore, in step 220 e
If xelsinv = 1 holds, it is determined that the electric device is being switched on / off. In this case, in step 154, the control switching flag F is set to "0", thereby returning from the ignition timing advance control to the normal control. On the other hand, in step 220, e
If xelsinv = 1 is not established, the current routine ends without operating the control switching flag F.

As described above, according to the routine shown in FIG. 7, the switching from the ignition timing advance control to the normal control is performed simultaneously with the on / off switching of the electric device mounted on the vehicle. Therefore, according to the present embodiment, the impact accompanying the return from the ignition timing advance control to the normal control is caused by the ON / OFF of the electric device.
It is generated at the same time as the impact accompanying the switching of the OFF state, and the number of times of occurrence of the impact is reduced, so that a feeling of strangeness to the driver is reduced.

FIG. 8 shows a fifth embodiment of the present invention.
5 is a flowchart of a routine executed by the CU 12.
In the routine shown in FIG. 8, when it is determined in step 152 that the load LS of the internal combustion engine 10 is equal to or smaller than the predetermined value B, the process of step 230 is executed next. In step 230, it is determined whether or not the AT shift flag exsft is set to "1". AT shift flag e
xsft is a flag that rises to “1” only when a shift is performed in the AT transmission. Therefore, if exsft = 1 is established in step 230, it is determined that the AT is shifting gears. in this case,
Next, at step 154, the control is switched from the ignition timing advance control to the normal control by setting the control switching flag F to "0". On the other hand, if exsft = 1 is not satisfied in step 230, the current routine ends without operating the control switching flag F.

As described above, according to the routine shown in FIG. 8, the return from the ignition timing advance control to the normal control is performed simultaneously with the AT shift. At the time of AT shifting, an impact is generated on the vehicle. Therefore, according to the present embodiment, the shock accompanying the return from the ignition timing advance control to the normal control is generated at the same time as the shock accompanying the shift of the AT, and the number of times of occurrence of the shock is reduced, so that the driver feels uncomfortable. It is reduced.

FIG. 9 is a circuit diagram showing a sixth embodiment of the present invention.
It is a flowchart of the routine which U12 performs. In the routine shown in FIG. 9, when it is determined in step 152 that the load LS of the internal combustion engine 10 is equal to or smaller than the predetermined value B, the process of step 240 is executed next. In step 240, it is determined whether the power steering operation flag exps is set to "1". The power steering operation flag exps is set to “1” when the power steering device of the vehicle is operating, that is, when the driver is performing the steering operation, and is set to “0” when the power steering device is not operating. Is set as the flag. Therefore, in step 240, exps = 1.
Is satisfied, it means that the power steering device is operating. In this case, in step 154, the control switching flag F is set to "0", thereby returning from the ignition timing advance control to the normal control. On the other hand, if exps = 1 is not satisfied in step 240, the current routine is terminated without operating the control switching flag F.

As described above, according to the routine shown in FIG. 9, when the power steering device is operating, that is, when the driver is performing the steering operation, the ignition timing advance control is changed to the normal control. Is returned. When the driver is performing a steering operation, it is difficult to be worried about the shock generated in the vehicle. According to the present embodiment, in such a case, the return from the ignition timing advance control to the normal control is performed, so that a feeling of strangeness to the driver is reduced.

In the first to sixth embodiments,
Combustion stability is ensured by ignition timing advance control. However, the present invention is not limited to this, and the combustion is stabilized by intake synchronous injection control in which fuel injection is performed during the opening period of the intake valve, or by injection amount increase control in which the fuel injection amount is increased from the normal time. It can also be applied effectively when securing the performance.

According to the intake-synchronous injection control, the amount of fuel contained in the exhaust gas increases because the fuel injection is performed during the opening period of the intake valve. On the other hand, in the normal control, the amount of fuel contained in the exhaust gas is reduced by performing control for performing fuel injection during the closing period of the intake valve (that is, intake asynchronous control). Therefore, due to the cooling effect of the fuel in the exhaust gas, during the execution of the intake synchronous injection control,
The catalytic converter 58 is more likely to be cooled than during the execution of the normal control. That is, when the control is returned from the intake synchronous injection control to the normal control, the cooling effect of the fuel on the catalytic converter 58 is reduced, and the temperature of the catalytic converter 58 is increased. Therefore, as in the first to sixth embodiments,
By performing the return from the intake synchronous injection control to the normal control during the low load operation of the internal combustion engine 10, it is possible to prevent the catalytic converter 58 from being damaged due to the temperature rise.

Similarly, when returning from the injection amount increase control to the normal control, the fuel amount in the exhaust gas decreases,
As the cooling effect of the fuel decreases, the temperature of the catalytic converter 58 increases. For this reason, as in the first to sixth embodiments, when the internal combustion engine 10 is operated at a low load, the control from the intake synchronous injection control to the normal control is performed, thereby deteriorating the catalytic converter 58 due to the temperature rise. Can be suppressed.

In both the intake synchronous injection control and the injection amount increase control, the combustion characteristics are stabilized,
The output torque of the internal combustion engine 10 increases as compared with the time of normal control. Therefore, at the time of returning from the intake synchronous injection control or the injection amount increasing control to the normal control, the torque decreases, and an impact is generated accordingly. Therefore, as in the second to sixth embodiments, the return to the normal control is performed by turning on / off the air conditioner.
By performing the operation at the same time as a phenomenon such as switching off, the driver's discomfort due to the impact can be reduced.

Next, a seventh embodiment of the present invention will be described. In the system according to the present embodiment, when the engine speed NE exceeds a predetermined value and the idle switch 64 is on, the engine speed NE becomes the predetermined maximum speed Nma.
x, when the driver's dozing is detected,
When the vehicle speed VW exceeds a predetermined maximum speed Vmax,
When the fuel injection amount (fuel injection time) falls below a predetermined value during low load operation or the like, and when the catalyst temperature Tc exceeds a predetermined temperature, fuel cut control for inhibiting fuel injection by the fuel injection valve 40 is performed. Be executed. Hereinafter, the fuel cut control executed in the following cases is referred to as idle-on F / C, overrun F / C, and drowsiness prevention F, respectively.
/ C, highest speed F / C, TAUMIN F / C, and F / C at high temperature of the catalyst.

The idle-on F / C is a fuel cut control executed to save fuel when the accelerator operation is not performed in the high-speed operation state. The overrun F / C is a fuel cut control executed to prevent the internal combustion engine 10 from rotating beyond a predetermined upper limit rotational speed. The drowsiness prevention F / C saves fuel and performs a fuel cut intermittently to warn the driver when the accelerator operation is performed due to the driver falling asleep while the vehicle is stopped. This is the fuel cut control to be executed. When the engine speed exceeds a predetermined value while the vehicle is stopped, and the shift lever is in the N or P range, it is determined that the driver is performing the accelerator operation while falling asleep.

The maximum speed F / C is a fuel cut control executed to prevent the vehicle speed VW from exceeding the legal maximum speed. The TAUMIN F / C is a fuel cut control executed to prevent such an inconvenience because the operation of the fuel injection valve 40 becomes unstable when the fuel injection amount becomes small as in the low load operation. It is.

The high temperature F / C of the catalyst is determined by the catalytic converter 5
Reference numeral 8 denotes a fuel cut control executed to prevent deterioration due to an excessive temperature rise. As described above, the ignition timing advance control is executed to improve the combustion stability of the internal combustion engine 10. Therefore, when returning from the ignition timing advance control to the normal control, the drivability may be degraded due to the combustion state changing to an unstable side. On the other hand, during execution of the fuel cut control, since combustion is not performed, even if the control returns from the ignition timing advance control to the normal control during that time, an instability of the combustion state and an impact due to a torque change cannot occur. . In the system of the present embodiment, the return from the ignition timing advance control to the normal control is performed during the execution of any one of the fuel cut controls described above.
Deterioration of drivability and occurrence of impact when control is restored are to be prevented.

The above functions are realized by the ECU 12 executing the routine shown in FIG. 10 instead of the routine shown in FIG. 3 in the system of the first embodiment. Hereinafter, the contents of the routine shown in FIG. 10 will be described. In FIG. 10, steps for performing the same processing as in the routine shown in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted.

In the routine shown in FIG.
If it is determined at 0 that the elapsed time ecfaf after the start of the FAF control is equal to or longer than A, then the process of step 300 is executed. In step 300, the fuel cut flag e
It is determined whether or not xfc is set to “1”. The fuel cut flag exfc is a flag that is set to “1” when any of the above-described fuel cut controls is executed. Therefore, when exfc = 1 is established in step 300, it is determined that the fuel cut control is being executed, and then in step 154, the control switching flag F is set to “0”, so that the ignition timing is advanced. After the return from the angle control to the normal control is performed, the current routine ends. On the other hand, step 30
If exfc = 1 is not satisfied at 0, the current routine ends without operating the control switching flag F.

As described above, according to the routine shown in FIG. 10, the return from the ignition timing advance control to the normal control is performed during the execution of the fuel cut control. Therefore, according to the system of the present embodiment, it is possible to prevent the drivability from deteriorating and the occurrence of an impact due to the return from the ignition timing advance control to the normal control. Next, an eighth embodiment of the present invention will be described. The system according to the present embodiment includes:
Only when the idle-on F / C, the overrun F / C, the drowsiness prevention F / C, and the maximum speed F / C are executed, the ignition timing advance control is returned to the normal control. ing. The above-described fuel cut control is executed when the engine is idling on during high-speed running. The fuel cut control is executed while the vehicle is stopped. The fuel cut control described above is performed at the engine speed NE.
Alternatively, it is executed to suppress the vehicle speed VW. During the execution of the fuel cut control, the temperature of the catalytic converter 58 does not become high. Therefore, even if the control returns from the ignition timing advance control to the normal control during that time, the catalytic converter 58 is not damaged. That is, according to the system of the present embodiment, when returning from the ignition timing advance control to the normal control,
It is possible to prevent the drivability from being deteriorated and the impact from being caused by the decrease in the combustibility, and to suppress the deterioration of the catalytic converter 58.

The above functions are realized by the ECU 12 executing the routine shown in FIG. 11 instead of the routine shown in FIG. 10 in the system of the seventh embodiment. Hereinafter, the contents of the routine shown in FIG. 11 will be described. In FIG. 11, steps that perform the same processing as the routine illustrated in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG.
If it is determined at 0 that the elapsed time ecfaf after the start of the FAF control is equal to or longer than A, the process of step 310 is executed next. In step 310, idle-on F / C
Flag exfcidle, overrun F / C flag e
xfcne, doze prevention F / C flag exfcneo
It is determined whether any one of r and the fastest F / C flag exfcspd is set to “1”. Idle-on F / C flag exfciddle,
Overrun F / C flag exfcne, doze prevention F
The / C flag exfcneor and the fastest F / C flag exfcspd are respectively
C, an overrun F / C, a doze prevention F / C, and a flag that is set to “1” during execution of the fastest F / C. Therefore, if the determination in step 310 is affirmative, it is determined that any of the fuel cut controls is being executed, and then the control switching flag F is set to "0" in step 154. After returning from ignition timing advance control to normal control by
This routine is ended. On the other hand, if a negative determination is made in step 310, the current routine ends without operating the control switching flag F.

Next, a ninth embodiment of the present invention will be described. In the system of the present embodiment, in the system of the seventh embodiment, even when the fuel cut control is being executed, if the fuel cut control is the TAUMIN F / C or the catalyst high temperature F / C, The feature is that the return from the ignition timing advance control to the normal control is prohibited. As described above, TAUMIN F / C is a fuel cut control that is executed to prevent the fuel injection amount of the fuel injection valve 40 from becoming unstable. If fuel injection is performed in such an unstable state, misfire and fuel may be repeated in the combustion chamber 28. In this case, the unburned fuel that has adhered to the catalytic converter 58 at the time of misfire is burned at the time of resuming combustion, so that the catalytic converter 58 enters a high temperature state. Similarly, the high-temperature catalyst F / C is a fuel cut control executed to prevent deterioration of the catalytic converter 58 due to a rise in temperature. During the high-temperature catalyst F / C, the catalytic converter 58 is in a high temperature state. I have. Under these circumstances, when the return from the ignition timing advance control to the normal control is performed, the temperature of the catalytic converter 58 rises due to the control return and the catalytic converter 58
Will damage it. According to the system of the present embodiment,
During execution of TAUMINF / C or F / C at the time of high temperature of the catalyst, it is possible to prevent the catalytic converter 58 from being damaged by prohibiting the return from the ignition timing advance control to the normal control.

The above functions are realized by the ECU 12 executing the routine shown in FIG. 12 instead of the routine shown in FIG. 10 in the system of the seventh embodiment. Hereinafter, the contents of the routine shown in FIG. 12 will be described. In FIG. 12, steps for performing the same processing as in the routine shown in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted.

In the routine shown in FIG.
If exfc = 1 holds at 0, then at step 320, the TAUMIN F / C flag exf
It is determined whether or not ctau is “0”. TAUM
The INF / C flag exfctau is set to TAUMIN
This flag is set to “1” during execution of F / C.
Therefore, in step 320, exctau = 0
Is satisfied, it is determined that the TAUMIN F / C is not being executed, and the process of step 322 is executed next. On the other hand, in step 320,
If 0 is not established, the current routine ends.

At step 322, it is determined whether or not the catalyst high temperature F / C flag exfcot is "0". The catalyst high temperature F / C flag exfcot is a flag that is set to “1” during execution of the catalyst high temperature F / C. Therefore,
In step 322, when exfcot = 0 is established, it is determined that the catalyst high-temperature F / C is not being executed. In this case, since the fuel cut control is being executed and neither the TAUMIN F / C nor the catalyst high-temperature F / C is being executed, the control switching flag F is set to “0” in step 154 next. Then, after the return to the normal control is performed, the current routine ends. On the other hand, in step 322, exfcot = 0
Is not established, the current routine is terminated without operating the control switching flag F.

Next, a tenth embodiment of the present invention will be described. The system according to the present embodiment is different from the system according to the seventh embodiment in that, even when the fuel cut control is being executed, if the catalytic converter 58 is in a high temperature state exceeding a predetermined temperature, the ignition timing advance control is changed to the normal control. The feature is that the return to is prohibited. That is, as described above, when the control returns from the ignition timing advance control to the normal control, the ignition timing changes to the retard side, and the temperature of the catalytic converter 58 rises. Therefore, according to the system of the present embodiment, when the catalytic converter 58 is in a high temperature state, the return from the ignition timing advance control to the normal control is prohibited, so that the damage due to the temperature rise of the catalytic converter 58 is prevented. Can be prevented.

The functions described above are realized by the ECU 12 executing the routine shown in FIG. 13 instead of the routine shown in FIG. 10 and further executing the routine shown in FIG. 14 in the system of the seventh embodiment. You. Less than,
The contents of the routine shown in FIGS. 13 and 14 will be described. First, the routine shown in FIG. 13 will be described. In FIG. 13, steps for performing the same processing as in the routine shown in FIG. 10 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG. 13, if exfc = 1 is satisfied in step 300, then in step 33
At 0, it is determined whether or not the catalyst high temperature flag Ftemp is “0”. As described later, the catalyst high temperature flag F
“temp” is a flag that is set to “1” when the temperature of the catalytic converter 58 exceeds a predetermined temperature and becomes high. Therefore, in step 330, Ftemp =
If 0 is established, it is determined that the catalytic converter 58 is not in the high temperature state, and then, in step 154, after the control switching flag F is set to “0”, the control is returned to the normal control. This routine is ended.
On the other hand, if Ftemp = 0 is not satisfied in step 330, the current routine ends without operating the control switching flag F.

Next, the routine shown in FIG. 14 will be described. The routine shown in FIG. 14 is executed to set the value of the catalyst high temperature flag Ftemp according to the catalyst temperature Tc.
When the routine shown in FIG.
50 processing is executed. In step 350, it is determined whether or not the catalyst temperature Tc exceeds a predetermined value T0. The predetermined value F is determined when the catalyst temperature Tc is equal to or lower than T0.
This is a value set as a temperature that does not damage the catalytic converter 58 even when the control returns from the ignition timing advance control to the normal control. In step 350, Tc> T
If 0 is satisfied, then, in step 352, the catalyst high temperature flag Ftemp is set to "1", and then the current routine ends. On the other hand, if Tc> T0 is not satisfied in step 350, then, in step 354, the catalyst high temperature flag Ftemp is set to “0”, and then the current routine ends.

In the seventh to tenth embodiments, the combustion state is stabilized by the ignition timing advance control. However, the present invention is not limited to this. The present invention can also be effectively applied to the case where the combustion state is stabilized by the injection amount increase control. That is, even when returning from the intake synchronous injection control or the injection amount increase control to the normal control, the combustion state becomes unstable, the impact due to the torque change, and the catalyst temperature rises. As described above, by performing control return during execution of the fuel cut control, it is possible to avoid these inconveniences.

Next, an eleventh embodiment of the present invention will be described. The system of the present embodiment is characterized in that the return from the ignition timing advance control to the normal control is performed when the vehicle is decelerated. That is, at the time of deceleration of the vehicle, even if the combustion state becomes unstable, drivability such as rattling does not deteriorate. Therefore, according to the system of the present embodiment,
By performing the return from the ignition timing advance control to the normal control at the time of deceleration of the vehicle, it is possible to prevent the drivability from being deteriorated due to the decrease in the combustion stability when the control is returned.

The above functions are realized by the ECU 12 executing the routine shown in FIG. 15 instead of the routine shown in FIG. 3 in the system of the first embodiment.
Hereinafter, the contents of the routine shown in FIG. 15 will be described.
In FIG. 15, steps that execute the same processing as the routine illustrated in FIG. 3 are denoted by the same reference numerals, and description thereof will be omitted. In the routine shown in FIG.
If ecfaf ≧ A is satisfied at 0, the process of step 400 is executed next.

In step 400, the idle switch 6
It is determined whether or not 4 is on. As a result, if the idle switch 64 is in the ON state, it is determined that the driver intends to decelerate, and the process of step 152 is executed next. On the other hand, if the idle switch 64 is not on in step 400, the current routine ends.

Even if the driver releases the accelerator operation, the load on the internal combustion engine 10 (ie, the amount of intake air) does not decrease immediately. For this reason, in step 152, LS ≦
If B is not satisfied, it is immediately after the accelerator operation is released, it is determined that the load LS has not yet decreased, and the current routine ends. On the other hand, if LS ≦ B is satisfied in step 152, then step 402
Is performed.

At step 402, it is determined whether or not the vehicle speed V exceeds a predetermined value C. During low-speed traveling, the gear ratio of the transmission is high, so that a change in torque of the internal combustion engine 10 is easily transmitted to the wheels. When the return from the ignition timing advance control to the normal control is performed in such a state, a large impact is generated due to a torque change accompanying the control return. Therefore, when V> C is satisfied in step 402, it is determined that the return from the ignition timing advance control to the normal control should not be performed, and the current routine is ended. On the other hand, if V> C is not satisfied in step 402, the process of step 404 is executed next.

In step 404, it is determined whether or not the load reduction rate DLS is less than a predetermined value D. Load reduction rate D
LS is, for example, a value obtained as a time reduction rate of the throttle opening. If DLS <D is not satisfied in step 404, the accelerator operation was quickly released, and
The combustion state is determined to be unstable. In this case, it is determined that there is a possibility that engine stall will occur when the control returns from the ignition timing advance control to the normal control, and the current routine is ended. On the other hand, if DLS <D is satisfied in step 404, then, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”. Will be terminated.

As described above, according to the routine shown in FIG. 15, when the load LS and the load reduction rate DLS are less than the predetermined values and the vehicle speed V exceeds the predetermined values, the driver intends to decelerate. Only when this is the case, the return from the ignition timing advance control to the normal control is performed. Therefore, according to the system of the present embodiment, it is possible to return from the ignition timing advance control to the normal control without causing damage due to a rise in the temperature of the catalytic converter 58, engine stall, and deterioration of drivability. it can.

Next, a twelfth embodiment of the present invention will be described. The system according to the present embodiment is different from the system according to the eleventh embodiment in that the return from the ignition timing advance control to the normal control is prohibited when the engine speed NE is lower than a predetermined value. Has features. If the return from the ignition timing advance control to the normal control is performed during the low speed operation of the internal combustion engine 10, the engine may stall due to the unstable combustion state. According to the system of the present embodiment, the engine stall of the internal combustion engine 10 can be more reliably prevented by prohibiting the return from the ignition timing advance control to the normal control during the low-speed operation.

The above functions are realized by the ECU 12 executing the routine shown in FIG. 16 instead of the routine shown in FIG. 15 in the system of the eleventh embodiment. Hereinafter, the routine shown in FIG. 16 will be described. In FIG. 16, the same reference numerals are given to the routines that perform the same processing as the routine illustrated in FIG. 15, and the description thereof will be omitted. In the routine shown in FIG.
In D4, if DLS <D is satisfied, the process of step 406 is executed next.

In step 406, it is determined whether or not the engine speed NE exceeds a predetermined value E. as a result,
If NE> E holds, it is determined that engine stall will not occur even if the control returns from the ignition timing advance control to the normal control. In this case, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”, and then the current routine is ended.
On the other hand, if it is determined in step 406 that NE> E is not satisfied, the current routine ends without returning to the normal control.

Next, a thirteenth embodiment of the present invention will be described. The system according to the present embodiment is different from the system according to the eleventh embodiment in that when the catalytic converter 58 is in a high temperature state, the return from the ignition timing advance control to the normal control is prohibited. The feature is that damage can be prevented. The above functions are
In the system of the eleventh embodiment, the ECU 12 is realized by executing the routine shown in FIG. 14 of the tenth embodiment in addition to executing the routine shown in FIG. 17 instead of the routine shown in FIG. You. Hereinafter, FIG.
The routine shown in FIG. 7 will be described. Note that, in FIG. 17, the same reference numerals are given to the routines that perform the same processing as the routine illustrated in FIG. 15, and description thereof will be omitted. In the routine shown in FIG.
If LS <D is satisfied, the process of step 410 is executed next.

At step 410, the catalyst high temperature flag Ft
It is determined whether or not emp is “0”. As described above, the catalyst high temperature flag Ftemp is a flag that is set to “1” when the temperature of the catalytic converter 58 exceeds a predetermined value in the routine shown in FIG. Therefore,
If Ftemp = 0 is satisfied in step 410, it is determined that the catalyst converter 58 will not be damaged even if the temperature of the catalytic converter 58 rises by returning from the ignition timing advance control to the normal control. . In this case, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”, and then the current routine is ended. On the other hand, if Ftemp = 0 is not satisfied in step 410, the current routine is terminated without returning to the normal control.

Next, a fourteenth embodiment of the present invention will be described. The system of the present embodiment is characterized in that, in the system of the above-described eleventh embodiment, a return from the ignition timing advance control to the normal control is performed when the shift position of the AT transmission is in a high gear state. That is, when the transmission is in the low gear state, a large impact is generated because a torque change accompanying the return from the ignition timing advance control to the normal control is easily transmitted to the wheels. According to the system of the present embodiment, by performing the return to the normal control in the state of the high gear, it is possible to reduce the impact caused by the return of the control to a small value.

The above performance is realized by the ECU 12 executing the routine shown in FIG. 18 instead of the routine shown in FIG. 15 in the system of the eleventh embodiment. Hereinafter, the contents of the routine shown in FIG. 18 will be described. Note that in FIG. 18, the same reference numerals are given to the routines that perform the same processing as the routine illustrated in FIG. 15, and description thereof will be omitted. In the routine shown in FIG. 18, when DLS <D is satisfied in step 404, the process of step 420 is executed next.

At step 420, it is determined whether the shift position esftout of the AT transmission is equal to or greater than a predetermined value G. Here, the shift position esftou
t is, for example, corresponding to a shift position from the first gear to the fourth gear,
It is set to an integer value from “1” to “4”. Step 42
At 0, if esftout ≧ G is satisfied, the high gear state is established, and it is determined that a large impact does not occur even if the control returns from the ignition timing advance control to the normal control.
In this case, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”, and then the current routine is ended. On the other hand, in step 420, if esftout ≧ G is not established, the current routine ends without returning to the normal control.

Next, a fifteenth embodiment of the present invention will be described. The system of the present embodiment is further characterized in that the return from the ignition timing advance control to the normal control is prohibited when the AT transmission is in the lock-up state in the system of the fourteenth embodiment. . That is,
In the lock-up state of the AT transmission, a change in torque of the internal combustion engine 10 is transmitted to the wheels without being reduced by the torque converter. If the return from the ignition timing advance control to the normal control is performed in such a state, a torque change accompanying the return is directly transmitted to the wheels, causing a large impact. According to the system of the present embodiment, by inhibiting the return to the normal control in the lock-up state of the AT transmission, it is possible to reduce the impact caused by the control return.

The above performance is realized by the ECU 12 executing the routine shown in FIG. 19 instead of the routine shown in FIG. 18 in the system of the fourteenth embodiment. Hereinafter, the contents of the routine shown in FIG. 19 will be described. In FIG. 19, the same reference numerals are given to the routines that perform the same processing as the routine illustrated in FIG. 18, and the description thereof will be omitted. In the routine shown in FIG. 19, if esftout ≧ G is satisfied in step 420, the process of step 422 is executed next.

At step 422, it is determined whether or not the AT transmission is in a lock-up state. As a result, when it is not in the lockup state, it is determined that a large impact does not occur even if the control returns from the ignition timing advance control to the normal control. In this case, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”, and then the current routine is ended. On the other hand, if it is determined in step 422 that the vehicle is in the lockup state, the current routine ends without returning to the normal control.

Next, a sixteenth embodiment of the present invention will be described. The system of the present embodiment is different from the system of the above-described eleventh embodiment in that the downshift of the AT transmission accompanying the deceleration, particularly the downshift on the high gear side (specifically, from the fourth gear to the third gear). Only the characteristic is that the control is returned from the ignition timing advance control to the normal control. At the time of downshifting of the AT transmission, an impact accompanying a shift is generated. Further, as described in the fourteenth embodiment, the impact due to the torque change is less likely to occur as the shift position of the transmission is on the higher gear side. Therefore, according to the system of the present embodiment, the return from the ignition timing advance control to the normal control is performed only during the downshift on the high gear side, so that the impact caused by the return can be suppressed small, and the impact can be suppressed. Is generated at the same time as the impact accompanying the downshift, so that the uncomfortable feeling given to the driver can be reduced.

The above performance is realized by the ECU 12 executing the routine shown in FIG. 20 instead of the routine shown in FIG. 15 in the system of the eleventh embodiment. Hereinafter, the contents of the routine shown in FIG. 18 will be described. Note that, in FIG. 20, the same reference numerals are given to the routines that perform the same processing as the routine illustrated in FIG. 15, and description thereof will be omitted. In the routine shown in FIG. 18, if DLS <D is satisfied in step 404, the process of step 430 is executed next.

At step 430, it is determined whether or not the downshift determination flag exsftout43 is set to "1". Shift down determination flag exsf
tout43 is for AT transmission from 4th gear to 3rd gear
This flag rises to "1" only when downshifting to high speed. Therefore, in step 440, exsft
When out43 = 1 is satisfied, it is determined that even if the control returns from the ignition timing advance control to the normal control, the driver does not feel a great sense of discomfort due to the impact accompanying the control return.
In this case, in step 154, the control is switched back to the normal control by setting the control switching flag F to “0”, and then the current routine is ended. On the other hand, in step 440, if exsftout43 = 1 is not satisfied, the current routine ends without returning to the normal control.

In the first to sixteenth embodiments, the combustion state is stabilized by the ignition timing advance control. However, the present invention is not limited to this. The present invention can also be effectively applied to the case where the combustion state is stabilized by the injection amount increase control. That is, even when returning from the intake synchronous injection control or the injection amount increase control to the normal control, the drivability may be deteriorated due to the unstable combustion state. Therefore, the first to the first
As in the sixth embodiment, by returning control when the vehicle decelerates, it is possible to prevent drivability from deteriorating.
Also, when returning from the intake synchronous injection control or the injection amount increasing control to the normal control, an impact occurs due to the torque change.
Therefore, as in the twelfth to sixteenth embodiments, the control return timing is limited to the time of high gear, downshift, and the like,
It is possible to alleviate the impact accompanying the return of control.

In the first to sixteenth embodiments, the ECU 12 is controlled by the ECU 12 shown in FIG. 3, FIG. 5 to FIG.
Steps 152 and 154, Steps 300 or 310, and 154 of the routine shown in FIG.
By executing the processing of 54, the “control return means” described in the claims is realized.
In the first to sixteenth embodiments, the ignition timing advance control, the intake synchronous injection control, and the injection amount increase control correspond to "combustion stabilization control" described in the claims.

[0086]

As described above, according to the first to fourth aspects of the present invention, when returning from the combustion stabilization control to the normal control,
It is possible to avoid inconveniences such as damage due to temperature rise of the catalyst, impact due to torque change, and deterioration of drivability due to instability of the combustion state.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a system to which a control device for an internal combustion engine of the present invention is applied.

FIG. 2 is a flowchart of a routine executed by an ECU to start ignition timing advance control in the first embodiment of the present invention.

FIG. 3 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the present embodiment.

FIG. 4 is a flowchart of a routine executed by an ECU to measure an elapsed time after the start of FAF control in the embodiment.

FIG. 5 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the second embodiment of the present invention.

FIG. 6 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a third embodiment of the present invention.

FIG. 7 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a fourth embodiment of the present invention.

FIG. 8 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a fifth embodiment of the present invention.

FIG. 9 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a sixth embodiment of the present invention.

FIG. 10 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a seventh embodiment of the present invention.

FIG. 11 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in an eighth embodiment of the present invention.

FIG. 12 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the ninth embodiment of the present invention.

FIG. 13 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the tenth embodiment of the present invention.

FIG. 14 is a flowchart of a routine executed by an ECU to set a catalyst temperature flag Ftemp in a tenth embodiment of the present invention.

FIG. 15 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the eleventh embodiment of the present invention.

FIG. 16 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in a twelfth embodiment of the present invention.

FIG. 17 is a flowchart of a routine executed by the ECU to return from the ignition timing advance control to the normal control in the thirteenth embodiment of the present invention.

FIG. 18 is a flowchart of a routine executed by the ECU to return from the ignition timing advance control to the normal control in the fourteenth embodiment of the present invention.

FIG. 19 is a flowchart of a routine executed by an ECU to return from ignition timing advance control to normal control in the fifteenth embodiment of the present invention.

FIG. 20 is a flowchart of a routine executed by the ECU in order to return from the ignition timing advance control to the normal control in the sixteenth embodiment of the present invention.

[Explanation of symbols]

 10 Internal combustion engine 12 ECU

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 43/00 301 F02D 43/00 301J F02P 5/15 F02P 5/15 B F-term (Reference) 3G022 AA06 BA01 CA00 CA05 CA09 DA01 DA02 EA00 EA03 FA03 GA00 GA01 GA05 GA06 GA09 GA10 GA12 GA17 GA19 GA20 3G084 AA04 BA13 BA15 BA17 CA00 CA03 CA06 DA11 DA19 DA34 EA11 EB02 EC02 EC03 FA18 FA38 3G301 HA01 HA15 JA04 JA31 JA02 JA37 KA08 KA08 KB MA11 MA18 NA08 NB06 NB11 NE17 NE23 PA01Z PA11Z PA14Z PA17Z PD02Z PD12Z PE01Z PE03Z PE08Z PF01Z PF07Z PF13Z PF16Z

Claims (4)

[Claims] 1. A control device for an internal combustion engine having a function of performing combustion stabilization control for improving combustion stability as compared with a normal control, wherein the combustion stabilization is performed at a timing according to an operation state of the internal combustion engine. A control device for an internal combustion engine, comprising: control return means for returning from control to normal control. 2. The internal combustion engine according to claim 1, wherein the control return unit performs a return from the combustion stabilization control to a normal control when a load on the internal combustion engine is equal to or less than a predetermined value. Control device. 3. The control return means, when the vehicle decelerates,
2. The control device for an internal combustion engine according to claim 1, wherein a return from the combustion stabilization control to a normal control is performed. 4. The control device for an internal combustion engine according to claim 1, wherein said control return means performs a return from said combustion stabilization control to a normal control when a fuel cut of said internal combustion engine is performed.