JP2002130016A - Controller for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain drivability from being worsened caused by improper execution in torque control for regulating leading of engine torque when an internal combustion engine transits from an idling condition to an off-idling condition. SOLUTION: When a gas flow control valve 48 is switched from a valve- closed condition to a valve-opened condition in accompaniment to the transition from the idling condition to the off-idling condition in a homogeneous charge combustion operation, the opened and closed conditions of the control valve 48 are switched after the torque control is finished, when the torque control is under execution to restrain torque shock accompanied to switching from a nonengaged condition to an engaged condition of a unidirectional clutch 3 in an automatic transmission 2. Thereby, the opened and closed conditions of the control valve 48 are switched during the torque control to restrain the opening and closing of the control valve 48 from being interfered by the torque control.

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.

[0002]

2. Description of the Related Art In recent years, an internal combustion engine such as an on-vehicle engine has been put into practical use in which the combustion system is switched between stratified combustion and homogeneous combustion in accordance with the operating state of the engine in order to improve fuel efficiency. I have. Further, in such a type of internal combustion engine, as described in, for example, the “Crown and Crown Majesta New Model Vehicle Description” issued on September 24, 1999, the gas in the combustion chamber is obtained so as to obtain good combustion of the air-fuel mixture. It is also known to provide an airflow control valve for changing the flow state in the intake passage of the engine.

[0003] In the internal combustion engine shown in the above document,
When the engine operating state is in the low-speed low-load region, the airflow control valve is opened to perform stratified combustion without the aid of gas flow in the combustion chamber. However, when the internal combustion engine is cold or when the internal combustion engine is idle and the brake booster negative pressure is insufficient, homogeneous combustion is performed with the airflow control valve closed and mixing is performed. We try to maintain good combustion of air. The reason why such good combustion can be obtained is that the gas flow in the combustion chamber is strengthened by closing the airflow control valve, and the mixing of air and fuel is promoted and the flame propagation of the air-fuel mixture is accelerated. That is because

Accordingly, in the idle state of the internal combustion engine (low rotation and low load state), for example, when the negative pressure of the brake booster is insufficient, the homogeneous combustion operation is performed with the airflow control valve closed, and the brake booster is operated. When the negative pressure is secured, switching from the homogeneous combustion to the stratified combustion is permitted. When the switching of the combustion mode is permitted in this way, when the internal combustion engine shifts from the idle state to the off-idle state, for example, during acceleration, the homogeneous combustion is switched to the stratified combustion. The reason why the combustion mode is switched in this way is that during a transition from the idle state to the off-idle state such as during acceleration, even if a torque shock accompanying the switching of the combustion mode occurs, it is less likely to be adversely affected by the torque shock. . At this time, the air flow control valve is also switched from the closed state to the open state.

In an internal combustion engine mounted on an automobile or the like, an output shaft thereof is connected to an automatic transmission or the like. For example, as shown in Japanese Patent Application Laid-Open No. 8-246913, the internal combustion engine is turned off from an idle state. When the engine torque rises with the transition to the idle state, a torque shock occurs depending on the operation state of the automatic transmission. Torque control is performed to suppress the rise of the engine torque so that such torque shock does not occur.
If this suppression is excessive, the acceleration performance will deteriorate,
The control amount of the torque control is adapted so that maintenance of acceleration performance and suppression of torque shock are compatible.

[0006]

However, when the torque control is executed when the internal combustion engine shifts from the idle state to the off-idle state, the airflow control valve is switched from the closed state to the open state as described above. May be used. The rise of the engine torque accompanying the transition from the idle state to the off-idle state of the internal combustion engine has a different tendency between when the airflow control valve is open and when it is closed. Therefore, when the airflow control valve is switched between the open state and the closed state through the opening and closing control when the torque control for suppressing the rise of the engine torque is performed, the opening and closing control of the airflow control valve is performed as described above. This interferes with the torque control, so that the torque control cannot be performed properly, and the drivability deteriorates.

The present invention has been made in view of such circumstances, and an object of the present invention is to appropriately perform torque control for adjusting the rise of engine torque when the internal combustion engine shifts from an idle state to an off-idle state. An object of the present invention is to provide a control device for an internal combustion engine that can suppress deterioration of drivability due to no longer being performed.

[0008]

The means for achieving the above object and the effects thereof will be described below. In order to achieve the above object, according to the first aspect of the invention, the flow state of gas in the combustion chamber is changed through opening and closing control of an airflow control valve provided in an intake system of the internal combustion engine, and the internal combustion under a predetermined condition is changed. In a control device for an internal combustion engine that performs torque control for adjusting a rise in engine torque when the engine transitions from an idle state to an off-idle state, the opening and closing of the airflow control valve is caused by the transition of the internal combustion engine from the idle state to the off-idle state. When switching the state, when the torque control is being executed, an opening / closing control means for switching the open / close state of the airflow control valve after the torque control ends is provided.

According to the above configuration, the open / close state of the airflow control valve is switched during the execution of the torque control, and the opening / closing control of the airflow control valve is prevented from interfering with the torque control.
It is possible to prevent the torque control from being properly performed due to the interference and the drivability from deteriorating.

As an example of the torque control, when the output shaft of the internal combustion engine is connected to the automatic transmission, the one-way transmission of the automatic transmission is performed in accordance with the transition from the idle state to the off-idle state of the engine. One example is torque control that suppresses a rise in engine torque when the clutch changes from a disengaged state to an engaged state.

According to a second aspect of the present invention, in the first aspect of the invention, when the torque control is not being executed, the opening / closing control means synchronizes with the transition of the internal combustion engine from the idle state to the off-idle state. Thus, the open / close state of the airflow control valve is switched.

According to the above configuration, when the open / close state of the airflow control valve is switched with the transition of the internal combustion engine from the idle state to the off-idle state, the open / close state of the airflow control valve is switched when torque control is not being performed. Can be suppressed from being delayed.

According to the third aspect of the present invention, the first or second aspect is provided.
In the invention described in the above, when switching the open / close state of the airflow control valve after the end of the torque control, the opening / closing control means may include a condition that an engine operating state reaches an operating region where the adverse effect of the engine torque difference due to the switching does not occur. The open / close state of the airflow control valve is switched.

According to the above configuration, when the open / close state of the airflow control valve is switched after the end of the torque control, it is possible to prevent the drivability from being deteriorated due to the engine torque difference accompanying the switching.

According to a fourth aspect of the present invention, in the third aspect of the invention, the open / close control means switches the open / close state of the airflow control valve after the end of the torque control.
The process is executed on condition that the engine operating state reaches an operating region where the engine torque obtained when the airflow control valve is opened and when the engine is closed is equal.

According to the above configuration, when the open / close state of the airflow control valve is switched after the end of the torque control, the resulting engine torque difference can be made substantially "0", and the drivability is reduced by the engine torque difference. Deterioration can be accurately suppressed.

According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, when the internal combustion engine shifts from the idle state to the off-idle state, the combustion mode of the air-fuel mixture is changed from the homogeneous combustion. The combustion mode of the internal combustion engine is switched from the homogeneous combustion to the stratified combustion on condition that the open / close state of the airflow control valve is switched when the idle state is shifted to the off-idle state. A switching control means is provided.

According to the above configuration, the switching to the stratified combustion is not performed when the flow state of the gas in the combustion chamber is not suitable for the stratified combustion, so that the deterioration of combustion due to the switching of the combustion mode is suppressed. However, stratified charge combustion can be executed as soon as possible after the shift to the off-idle state, and deterioration in fuel efficiency due to continuation of homogeneous combustion can be suppressed. Therefore, at the time of transition from the idle state to the off-idle state, it is possible to achieve both suppression of deterioration in combustion due to switching of the combustion mode and suppression of deterioration in fuel consumption.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a direct injection spark ignition type engine mounted on an automobile will be described below with reference to FIGS.

The engine 11 shown in FIG. 1 has a fuel injection valve 40 for directly injecting fuel into the combustion chamber 16 to which an intake passage 32 and an exhaust passage 33 are connected, and ignites an air-fuel mixture in the combustion chamber 16. And a spark plug 41 for burning the air-fuel mixture. Then, the piston 12 of the engine 11 reciprocates based on the combustion of the air-fuel mixture in the combustion chamber 16, and this reciprocation is converted by the connecting rod 13 into rotation of a crankshaft 14 as an output shaft.

In the intake passage 32 of the engine 11, a throttle valve 23 for adjusting the amount of air taken into the combustion chamber 16 and a pressure (intake pressure PM) downstream of the throttle valve 23 in the intake passage 32 are detected. A vacuum sensor 36 is provided. The degree of opening of the throttle valve 23 is determined based on a detection signal from an accelerator position sensor 26 that detects the amount of depression of an accelerator pedal 25 (accelerator depression amount ACCP) of the vehicle.
4 is changed by controlling the driving.

In the intake passage 32 of the engine 11, a portion near the downstream end thereof is connected to the combustion chamber 16 in a state of being branched into two parts. An airflow control valve 48 for changing the flow state is provided. And the airflow control valve 4
When the airflow control valve 4 is opened, the airflow area of the intake passage 32 is increased and the intake resistance of the engine 11 is reduced.
When the shutter 8 is closed, the air flow area of the intake passage 32 is reduced, and the flow velocity of the air sucked into the combustion chamber 16 is increased.

On the other hand, the crankshaft 1 of the engine 11
4 is connected to the automatic transmission 2 mounted on the automobile. The automatic transmission 2 has, for example, five forward speeds and one reverse speed, and operates a one-way clutch 3 and a friction engagement device such as various clutches and brakes provided in the automatic transmission 2. In this case, one of the above-mentioned shift speeds is selected.

The drive control of the engine 11 and the automatic transmission 2 is performed by an electronic control unit (hereinafter referred to as an ECU) 92. That is, the ECU 92 performs various controls on the engine 11 such as fuel injection control, ignition timing control, opening / closing control of the airflow control valve 48, opening / closing control of the throttle valve 23, and switching control of the combustion mode.
Various controls, such as a shift speed switching control, are performed for.

The ECU 92 includes the automatic transmission 2, the throttle motor 24, the accelerator position sensor 26,
A crank position sensor 14 to which a vacuum sensor 36 and a fuel injection valve 40 are connected and which outputs a pulse signal corresponding to the rotation of the crankshaft 14
c, an igniter 4 for controlling the ignition timing of the ignition plug 41
1a and an actuator 4 for opening and closing the airflow control valve 48
9 are connected.

The ECU 92 switches the combustion mode of the air-fuel mixture between stratified combustion and homogeneous combustion in accordance with the engine operating conditions such as the engine speed NE and the load factor KL. Here, the engine speed NE is obtained based on a detection signal from the crank position sensor 14c. The load factor KL is a value indicating the current load ratio with respect to the maximum engine load, and is calculated based on a parameter corresponding to the intake air amount of the engine 11 and the engine speed NE. The parameter corresponding to the intake air amount is an intake pressure PM obtained from a detection signal of the vacuum sensor 36.
And an accelerator depression amount ACCP obtained from a detection signal of the accelerator position sensor 26.

During the stratified charge combustion operation of the engine 11, the mixture is burned by the fuel injection in the compression stroke in a state where the combustible mixture exists only around the ignition plug 41.
It is possible to improve the fuel efficiency by making the air-fuel ratio of the air-fuel mixture leaner than the stoichiometric air-fuel ratio. Further, during the homogeneous combustion operation of the engine 11, the fuel mixture is burned in a state in which the fuel is uniformly mixed with the air by the fuel injection in the intake stroke, so that the fuel concentration of the entire mixture is increased. High output can be obtained.

Therefore, for example, when the operation state of the engine 11 is in the stratified combustion operation area in the low-speed low-load area, stratified combustion is executed to improve fuel efficiency, and the operation state is higher than the low-speed low-load area. When the engine is in the homogeneous combustion operation range on the high rotation speed side, homogeneous combustion is executed to obtain a required engine output. By switching the combustion mode in this way, it is possible to achieve both improvement in fuel efficiency and obtaining a required engine output.

The switching of the combustion mode between the stratified combustion and the homogeneous combustion is performed by changing the value of the operation mode MODE set through the ECU 92, for example, "0 (stratified combustion)", "1".
(Homogeneous combustion) ". That is, for example, when the operation state of the engine 11 is in the stratified combustion operation region, the ECU 92 operates in the operation mode MODE.
Is set to “0”, and stratified combustion is executed based on “MODE = 0”. The ECU 92 sets the operation mode MODE to “1” when the operation state of the engine 11 is in the homogeneous combustion operation range, for example, and sets “MODE =
The homogeneous combustion is executed on the basis of “1”.

Since the stratified charge combustion and the homogeneous charge combustion have different forms of the air-fuel mixture in the combustion chamber 16, even under the same engine operating condition, the fuel injection amount and the fuel amount suitable for each combustion form are determined. The fuel injection timing, ignition timing, throttle opening, etc. are different from each other. Therefore, the ECU 92 sets the fuel injection valve 40, the igniter 41a, and the like so as to obtain the fuel injection amount, the fuel injection timing, the ignition timing, the throttle opening, and the like suitable for the combustion mode to be executed.
And the throttle motor 24 and the like.

The ECU 92 determines the engine speed NE.
The actuator 49 is controlled based on the engine operating state such as the load factor KL and the like to change the open / close state of the airflow control valve 48. Based on the opening / closing control of the airflow control valve 48,
During the stratified charge combustion operation, the airflow control valve 48 is closed. In addition, during the homogeneous combustion operation, the airflow control valve 48 is opened in the high rotation and high load region, and the airflow control valve 48 is closed in other regions.

The opening / closing control of the air flow control valve 48 is as follows: During the stratified charge combustion operation, a combustible mixture is formed around the ignition plug 41 without the aid of the gas flow in the combustion chamber 16.

When the homogeneous combustion operation is performed and the operation state is in the high rotation and high load region, the airflow control valve 48 is opened to minimize the increase in intake resistance caused by closing the valve 48 as much as possible. Preferably, it is suppressed.

When the homogeneous combustion operation is performed and the operation state is in a region other than the high rotation and the high load, the turbulent flow is generated in the combustion chamber 16 by closing the airflow control valve 48, so that air and fuel And the combustion chamber 16
It is preferable to increase the flow rate of the gas sucked into the inside to improve the intake charging efficiency. And so on.

On the other hand, the ECU 92 determines the gear position of the automatic transmission 2 and whether the one-way clutch 3 is in the engaged state or the disengaged state. Further, E
The CU 92 obtains the vehicle speed SPD of the vehicle based on the rotation speed of the output shaft 2a of the automatic transmission 2, and sets the gear position of the automatic transmission 2 to the optimal gear based on the vehicle speed SPD, the accelerator depression amount ACCP, and the like.

When the speed of the automatic transmission 2 is set to the first speed and the accelerator depression amount ACCP is set to "0" (idle state) and the vehicle decelerates,
The one-way clutch 3 for achieving the speed is disengaged. In this state, when the accelerator pedal 25 is depressed for re-acceleration of the vehicle and the accelerator depression amount ACCP becomes larger than “0” (off-idle state), the engine 11 in the coasting state actively rotates. Like
Accordingly, the one-way clutch 3 in the disengaged state is switched to the engaged state.

When the engine torque rises with the transition from the idle state of the engine 11 to the off-idle state as described above, particularly when the speed of the automatic transmission 2 is set to the first speed, the one-way When the clutch 3 is switched from the disengaged state to the engaged state, the switching causes a torque shock when the engine torque rises. The ECU 92 executes torque control for suppressing the rise of the engine torque in order to suppress the occurrence of such a torque shock.

The torque control performed through the ECU 92 is performed by adjusting at least one of an engine control system that affects the engine torque, for example, at least one of an intake system, an ignition system, and a fuel injection system using a predetermined control amount. It is performed by If the rise of the engine torque is excessively suppressed by this torque control, the acceleration performance deteriorates.
The control amount is adapted so that the maintenance of the acceleration performance and the suppression of the torque shock are compatible.

When the engine 11 changes from the idle state to the off-idle state, the torque control is normally performed during the stratified combustion operation because the operating state is in the low-speed low-load region. Such torque control during the stratified combustion operation is realized by adjusting the fuel injection system with a predetermined control amount, for example, by reducing the fuel injection amount of the engine 11.

However, even in an idle state (low-speed low-load state), homogeneous combustion may be performed with the airflow control valve 48 closed. In this case, the switching from the homogeneous combustion in the idling state to the stratified combustion is performed by the engine 1.
1 is performed based on the transition from the idle state to the off-idle state. The reason why such switching of the combustion mode is limited to the transition from the idle state to the off-idle state is that at that time, even if a torque shock occurs due to the switching of the combustion mode, it is difficult to feel the shock.

As described above, when homogeneous combustion is performed even when the engine operating state is in a low-speed low-load region such as an idling state, when the torque control is started along with the transition from the idling state to the off-idling operation state, the homogeneous operation is started. Torque control is performed during the combustion operation. Such torque control during the homogeneous combustion operation is realized by adjusting the intake system and the ignition system with a predetermined control amount, for example, by reducing the intake air amount of the engine 11 or delaying the ignition timing. .

Next, the execution procedure of the torque control will be described in detail with reference to a flowchart of FIG. 2 showing a re-acceleration torque control routine. This re-acceleration torque control routine is periodically executed through the ECU 92 by, for example, time interruption at predetermined time intervals.

As a process of the torque control routine at the time of re-acceleration, it is first determined whether or not the torque control execution flag F is "0 (stop)". This torque control execution flag F is
This is for determining whether or not the torque control is being executed, and is set to “0 (stop)” or “1” by a process described later.
(Execute) ".

If an affirmative determination is made in the process of step S101, it is determined that the torque control is stopped, and the processes of steps S102 to S107 for starting the torque control when a predetermined start condition is satisfied are executed. Is done.

The determination as to whether or not the above start condition is satisfied
Whether the gear position of the automatic transmission 2 is the first speed (S10
2) Whether the vehicle speed SPD is in a predetermined low speed range such as 8 to 15 km (S103), whether the one-way clutch 3 is in the disengaged state (S104), and immediately after the accelerator pedal 25 is depressed. The determination is performed based on whether or not there is (S105). Then, the above S102 to S1
When all of the processes in step 05 are affirmatively determined, it is determined that the start condition for starting the torque control is satisfied, the torque control execution flag F is set to “1 (execution)”, and the torque control execution flag F is set to “1 (execution)”. Control is started (S106, S
107).

By this torque control, the one-way clutch 3 is used when shifting from the idle state to the off-idle state.
Is switched from the disengaged state to the engaged state, the rise of the engine torque is suppressed, and the occurrence of torque shock is suppressed. Here, this torque control will be described in detail with reference to an example of the torque control in the case of transition from the idle state to the off-idle state in the homogeneous combustion operation.

When the torque control during the homogeneous combustion operation is started based on the re-acceleration of the vehicle, the throttle valve 23 is temporarily opened to increase the engine speed NE, and then closed. Controlled. Then, after the throttle valve 23 is controlled to close, the ignition timing is controlled to retard.

By controlling the throttle valve 23 to the closed side and controlling the ignition timing to the retarded side, no torque shock occurs when the one-way clutch 3 changes from the disengaged state to the engaged state. As described above, the rise of the engine torque accompanying the transition from the idle state to the off-idle state is suppressed. The control amount for controlling the throttle valve 23 to the closing side and the control amount for controlling the ignition timing to the retard side are controlled while maintaining the acceleration performance of the vehicle.
The torque shock is adapted to be suppressed.

After the start of the torque control, the torque control execution flag F becomes "1 (execution)", so a negative determination is made in the processing of step S101, and a step for ending the torque control at a predetermined timing. S108 ~
The process of S110 is performed.

That is, it is determined whether or not a predetermined time t1 has been started since the start of the torque control (S108). If the determination is affirmative, the torque control execution flag F is set to "0 (stop)" and Then, the torque control is stopped (S109, S110). After the torque control is stopped, the throttle opening and the ignition timing are controlled as usual.

Next, when shifting from the state in which the idling operation in the homogeneous combustion is being performed to the off-idle state, how the accelerator depression amount ACCP, the torque control execution flag F, the air flow control valve 48, and the operation mode MODE are changed. Will be described with reference to the time chart of FIG.

In the idle state during the homogeneous combustion operation, the operation mode MODE is set to "1 (homogeneous combustion)" and the accelerator depression amount ACCP becomes "0" (idle state). In addition, when the homogeneous combustion operation is performed in the idling state, since the engine operation state is not in the high-speed high-load region, the mixing of air and fuel in the air-fuel mixture is promoted, and good combustion is performed. As shown in FIG. 3C, the airflow control valve 48 is closed.

Thereafter, the accelerator depression amount ACCP becomes "0".
3B (off-idle state), the dashed line in FIG. 3B is provided on condition that the gear position of the automatic transmission 2 is the first speed and the one-way clutch 3 is in the disengaged state. , The torque control execution flag F is set to “1 (execution)”. Then, as described above, in order to suppress the torque shock when the one-way clutch 3 is switched, the torque control for suppressing the rise of the engine torque due to the transition from the idle state to the off-idle state is executed.

When the operating state is in the stratified combustion operation region when the engine 11 shifts from the idle state to the off-idle state as described above, the combustion mode is switched from the homogeneous combustion to the stratified combustion. The stratified combustion is performed in the combustion chamber 1
Since the operation is performed without the aid of the gas flow in 6, the air flow control valve 48 is opened in the stratified combustion operation region. However, if the switching of the open / close state of the airflow control valve 48 is performed during the execution of the torque control, there is an adverse effect that the torque control cannot be appropriately performed.

This is because the rise of the engine torque accompanying the transition of the engine 11 from the idle state to the off-idle state tends to be different between when the airflow control valve 48 is closed and when it is open. That is the cause. That is,
If the open / close state of the airflow control valve 48 is switched during the torque control, the opening / closing of the airflow control valve 48, which affects the tendency of the engine torque to rise, interferes with the torque control, and the torque control can be performed appropriately. And the drivability deteriorates.

Therefore, in the present embodiment, when the airflow control valve 48 is switched as described above with the transition from the idle state to the off-idle state, torque control is being executed (“F
= 1 ”), the airflow control valve 48 is temporarily fixed in a closed state as shown by a broken line in FIG. As described above, when the airflow control valve 48 is fixed in the closed state, the operation mode MODE is fixed to "1 (homogeneous combustion)" to prohibit switching from homogeneous combustion to stratified combustion.

The torque control is terminated after a predetermined time t1 has elapsed from the start, but after the torque control is terminated, the fixed state of the airflow control valve 48 in the closed state is released, and the airflow control valve 48 is closed. Switching from to the open state is permitted. Then, based on the permission of switching of the airflow control valve 48, the airflow control valve 48 that has been in the closed state is opened as shown by a broken line in FIG.

As described above, during the torque control, the airflow control valve 4
8, the open / close state of the air flow control valve 8 is switched, and the torque control is interfered with the opening / closing of the airflow control valve 48, so that it is not possible to appropriately perform the torque control.

When a predetermined time t2 elapses after the air flow control valve 48 is released from being fixed in the closed state, the operation mode MODE is released from being fixed at "1 (homogeneous combustion)".
Switching of the operation mode MODE is permitted. Therefore, based on the switching permission, the operation mode MO
DE is switched to “0 (stratified combustion)” as indicated by a broken line in FIG. 3D, and the combustion mode of the engine 11 is switched from homogeneous combustion to stratified combustion.

Next, a description will be given of the control procedure of the air flow control valve 48 and the combustion mode when transitioning from the idle state to the off-idle state in the homogeneous combustion operation with reference to FIG. 4 and FIG. 4 and 5 are flowcharts showing an acceleration control routine for fixing and releasing the fixing of the airflow control valve 48 and the operation mode MODE. This control routine at the time of acceleration is periodically executed through the ECU 92 by, for example, time interruption at predetermined time intervals.

As a process of the acceleration control routine, first, it is determined whether or not torque control is being executed in accordance with the transition from the idle state to the off-idle state in the homogeneous combustion operation. This determination is made as to whether or not the engine is idling in the homogeneous combustion operation (S201 (FIG. 4)) and whether or not it is immediately after depressing the accelerator (S201).
202) and whether or not the torque control execution flag F is “1 (execution)” (S203).

Then, the above steps S201 to S203
If a positive determination is made in all of the processes, it is determined that the torque control is being executed with the transition from the idle state to the off-idle state in the homogeneous combustion operation, and the airflow control valve 48
Is fixed in the valve closed state as shown by the broken line in FIG. 3C, and the operation mode MODE is fixed to "1 (homogeneous combustion)" as shown by the broken line in FIG.
S205).

When a negative determination is made in any of the above-described steps S201 to S203, and it is determined that torque control is not being executed in the transition from the idle state to the off-idle state in the homogeneous combustion operation, Does not fix the airflow control valve 48 and the operation mode MODE. Therefore, based on the transition from the idle state to the off-idle state, the switching of the open / close state of the airflow control valve 48 and the switching of the operation mode MODE are performed as usual.

That is, in synchronization with the transition from the idle state to the off-idle state, the airflow control valve 48 is switched from the closed state to the open state as shown by the solid line in FIG. Then, after a predetermined time has elapsed, the operation mode MOD
E is “0 (stratified combustion)” as shown by the solid line in FIG.
The combustion mode of the engine 11 is switched from homogeneous combustion to stratified combustion based on this. If there is no request to open the airflow control valve 48, the airflow control valve 48
And the homogeneous combustion operation of the engine 11 is continued.
When the operation state is not in the stratified combustion operation region, the homogeneous combustion operation of the engine 11 is continued.

On the other hand, in the process of step S206 shown in FIG. 5, it is determined whether or not the airflow control valve 48 is fixed in the closed state. Steps S207 to S211 for canceling the fixed state of the airflow control valve 48 in the closed state are executed. In the processing of steps S207 to S210, it is determined whether or not the torque control has ended and the engine operating state has reached an operating region where the adverse effect of the engine torque difference due to the switching of the open / close state of the airflow control valve 48 does not occur.

This determination is made as to whether the torque control execution flag F is "0 (stop)" (S206), and whether the load factor KL
Is larger than a predetermined value α (S208), and whether the engine speed NE is larger than a predetermined value β (S20).
9) and whether the vehicle speed SPD is higher than the predetermined value γ (S210).

Then, an affirmative determination is made in the processing of step S207, and the processing in steps S208 to S2 is performed.
An affirmative determination is made in any of the processes of FIG. 10, and it is determined that the torque control has been completed and that the engine operating state has reached an operating region in which the adverse effect of the engine torque difference due to switching of the open / close state of the airflow control valve 48 does not occur. Then, the fixing of the airflow control valve 48 in the closed state is released (S211).

At this time, if there is a request to open the air flow control valve 48, the air flow control valve 48 is switched from the closed state to the open state as shown by the broken line in FIG. When the open / close state of the airflow control valve 48 is switched in this manner, the engine torque difference accompanying the switching does not adversely affect the switching.
The predetermined values α, β, and γ used in steps S208 to S210 are set in advance.

Note that "KL> α (S208)" and "NE
> Β (S209) ”or“ SPD> γ (S209) ”
Is satisfied, the engine torque difference caused by the switching of the open / close state of the airflow control valve 48 has no adverse effect. When these conditions are satisfied, the engine torque difference is hardly felt by the vibration of the engine 11 or the automobile. That's why.

After the fixing of the airflow control valve 48 in the closed state is released, if an affirmative determination is made in the determination (S212) as to whether or not a predetermined time t2 has elapsed since the release of the fixing, "1"
The switching of the operation mode MODE fixed at "(homogeneous combustion)" is permitted, and is switched to "0 (stratified combustion)" as shown by the broken line in FIG. At this time,
When the operation mode MODE is switched to “0”, the combustion mode of the engine 11 is switched from homogeneous combustion to stratified combustion.

According to the above-described embodiment, the following effects can be obtained. (1) When the airflow control valve 48 is switched from the closed state to the open state with the transition from the idle state to the off-idle state in the homogeneous combustion operation, the one-way clutch 3 is changed from the non-engaged state to the engaged state. When the torque control for suppressing the torque shock accompanying the switching of
After the torque control ends, the open / close state of the airflow control valve 48 is switched. Therefore, the open / close state of the airflow control valve 48 is switched during the torque control, and the airflow control valve 48 is switched.
Can prevent drivability from deteriorating due to interference with torque control due to opening and closing of the motor.

(2) When the airflow control valve 48 is switched from the closed state to the open state in accordance with the transition from the idle state to the off-idle state in the homogeneous combustion operation, when the torque control is not being executed, the idle state is changed from the idle state. Switching of the open / close state of the airflow control valve 48 is performed in synchronization with the transition to the off-idle state. Therefore, when the torque control is not being performed as described above, it is possible to suppress an unnecessary delay in switching the airflow control valve 48 from the closed state to the open state.

(3) Switching from the closed state to the open state of the airflow control valve 48 after the end of the torque control means that the engine operating state has reached an operating region where the adverse effect of the engine torque difference due to the switching does not occur. Done on condition. Therefore, when the open / close state of the airflow control valve 48 is switched as described above, it is possible to suppress the drivability from being deteriorated due to the accompanying engine torque difference.

(4) Switching from the homogeneous combustion to the stratified combustion in the combustion mode accompanying the transition from the idle state to the off-idle state in the homogeneous combustion operation is performed by fixing the airflow control valve 48 in the closed state after the torque control is completed. Predetermined time t after release
2 has elapsed and the operation mode MODE is "0 (stratified combustion)"
This is performed based on the fact that switching to is permitted. Therefore, the combustion mode is switched on the condition that the air flow control valve 48 is released from being fixed in the closed state and the valve 48 is switched from the closed state to the open state. As a result, when the flow state of the gas in the combustion chamber 16 is not suitable for stratified combustion, the combustion mode is not switched from homogeneous combustion to stratified combustion. Stratified combustion can be executed as soon as possible after the shift to the idle state, so that deterioration in fuel efficiency due to continuation of homogeneous combustion can be suppressed. Therefore, it is possible to achieve both suppression of deterioration of fuel consumption while suppressing deterioration of combustion due to switching of the combustion mode.

The present embodiment can be modified as follows, for example. In the present embodiment, after the torque control is completed, the airflow control valve 48
When opening the valve 48 by releasing the lock in the closed state, the torque control is terminated and the adverse effect of the engine torque difference due to the switching of the open / close state of the airflow control valve 48 is caused by the engine operating state. The operation is performed under the condition that the operating region has not been generated, but the present invention is not limited to this. For example, the release of the fixed state of the airflow control valve 48 in the closed state is performed when the torque control is completed and the engine operating state becomes equal to the engine torque obtained when the airflow control valve 48 is closed and when the airflow control valve 48 is opened. Is reached, and the airflow control valve 48 may be switched from the closed state to the open state when the condition is satisfied. In this case, when the opening / closing state of the airflow control valve 48 is switched, the engine torque difference accompanying the switching can be made substantially “0”, and the drivability is prevented from deteriorating due to the engine torque difference. be able to.

In this embodiment, if the torque control is not executed at the time of the transition from the idle state to the off-idle state in the homogeneous combustion operation, the air flow control valve 48 is closed at the same time as the transition from the idle state to the off-idle state. Although the fixing in the valve state is released, the present invention is not limited to this. That is, instead of simultaneously with the transition from the idle state to the off-idle state, the fixed state of the airflow control valve 48 in the closed state may be released after a predetermined time has elapsed from this transition.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing an entire engine to which an engine control device according to an embodiment is applied.

FIG. 2 is a flowchart showing an execution procedure of torque control performed at the time of re-acceleration of the vehicle.

FIG. 3 is a diagram showing an accelerator depression amount ACCP, a torque control execution flag F, an airflow control valve, and an operation mode M when shifting from an idle state to an off-idle state in a homogeneous combustion operation.
6 is a time chart showing how ODE changes.

FIG. 4 is a flowchart showing a control procedure of an airflow control valve 48 and a combustion mode when shifting from an idle state to an off-idle state in a homogeneous combustion operation.

FIG. 5 is a flowchart showing a control procedure of an airflow control valve 48 and a combustion mode when shifting from an idle state to an off-idle state in a homogeneous combustion operation.

[Explanation of symbols]

2 ... automatic transmission, 3 ... one-way clutch, 11 ... engine, 14c ... crank position sensor, 23 ... throttle valve, 24 ... throttle motor, 25 ... accelerator pedal, 26 ... accelerator position sensor, 32 ... intake passage, 33 ... Exhaust passage, 36 ... Vacuum sensor, 4
0: fuel injection valve, 41: spark plug, 41a: igniter, 48: air flow control valve, 92: electronic control unit (EC
U).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 45/00 312 F02D 45/00 312E 312C F-term (Reference) 3G023 AA00 AA18 AB01 AC04 AD06 AD29 AG01 3G084 AA04 BA02 BA05 BA17 BA21 CA03 CA04 CA09 DA11 EA07 EA11 EC01 FA10 FA11 FA18 FA33 3G301 HA16 HA17 JA04 KA07 KA09 KA14 KA25 KB10 LA00 LA03 LA07 LC03 NA08 NE15 NE16 NE22 NE23 PA07Z PA17Z PE01Z PF01Z PF03Z PF06Z

Claims (5)

[Claims] An internal combustion engine includes a gas flow control valve provided in an intake system of an internal combustion engine. The gas flow state in a combustion chamber is changed by opening and closing control of the internal combustion engine. In the control device of the internal combustion engine that performs torque control to adjust the rise of the engine torque at the time of the transition, when switching the open / close state of the airflow control valve with the transition of the internal combustion engine from the idle state to the off-idle state,
A control device for an internal combustion engine, comprising: an opening / closing control unit that switches the open / close state of the airflow control valve after the torque control is completed when the torque control is being executed. 2. The open / close control means switches the open / close state of the airflow control valve in synchronization with a transition from an idle state to an off-idle state of the internal combustion engine when the torque control is not being executed. Internal combustion engine control device. 3. The switching control means according to claim 1, further comprising: switching an open / close state of the airflow control valve after the end of the torque control.
3. The open / close state of the airflow control valve is switched on condition that the engine operating state has reached an operating range in which the switching does not adversely affect the engine torque difference.
A control device for an internal combustion engine according to claim 1. 4. The engine control system according to claim 1, wherein the on / off control means switches the open / close state of the airflow control valve after the end of the torque control by changing the engine operating state between when the airflow control valve is open and when the airflow control valve is closed. 4. The control device for an internal combustion engine according to claim 3, wherein the control is executed under a condition that an operating range in which the values of. 5. The control device for an internal combustion engine according to claim 1, wherein, when the internal combustion engine shifts from an idle state to an off-idle state, the combustion mode of the air-fuel mixture is from homogeneous combustion to stratified combustion. Wherein the combustion mode of the internal combustion engine is switched from homogeneous combustion to stratified combustion on the condition that the open / close state of the airflow control valve is switched at the time of transition from the idle state to the off-idle state. A control device for an internal combustion engine, comprising control means.