JP2001342878A - Control device of internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a shock and vibration caused by performing fuel cut control. SOLUTION: This control device of an internal combustion engine for performing the fuel cut control for stopping supply of fuel to the internal combustion engine at traveling time, is provided with at least either one means of a fuel cut just before time control means (Step S5 and S6) for controlling torque to a driving wheel from the internal combustion engine in the reducing direction in a motive power system up to the driving wheel from the internal combustion engine just before performing the fuel cut control when judging the performance of the fuel cut control and a fuel cut just after time control means for controlling the torque to the driving wheel from the internal combustion engine in the increasing direction in the motive power system up to the driving wheel from the internal combustion engine just after performing the fuel cut control when performing the fuel cut control.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling an internal combustion engine that outputs power by burning fuel, such as a gasoline engine, and in particular, stops the supply of fuel during operation to improve fuel efficiency. The present invention relates to a control device that executes fuel cut control.

[0002]

2. Description of the Related Art In an internal combustion engine such as a gasoline engine,
Starting from a stopped state must be performed by forcibly rotating with an external force such as a motor, but when the vehicle is running with inertial force, such as during deceleration, that is, during coasting, the engine is forcibly rotated by external force. Since the rotation can be maintained, the fuel supply is stopped to improve the fuel efficiency. This is so-called fuel cut control.

[0003] Fuel cut control is executed within a range of rotation speeds at which the engine can maintain autonomous rotation by restarting fuel supply. That is, the supply of fuel is stopped while the engine speed decreases to the return speed during deceleration. If control is performed so that the engine speed does not decrease to its return speed, the fuel supply suspension period will be prolonged, and the effect of improving fuel efficiency will be excellent. Is set so as to be close to a so-called mechanically directly connected state, thereby preventing a decrease in the engine speed due to a so-called slip in the power system. One example is control in which the engine speed during deceleration is relatively high by engaging a lock-up clutch (directly-coupled clutch) in a fluid transmission device such as a torque converter.

However, since the lock-up clutch is a device for mechanically connecting the input side member and the output side member instead of the fluid, the lock-up clutch also transmits the torque fluctuation as it is. Therefore, for example, when the engine speed is reduced to a so-called return speed and fuel supply is restarted, the engine that has been forcibly rotated by an external force starts to autonomously rotate due to fuel combustion, that is, torque is output. Therefore, the state of the torque acting on the power system from the engine to the drive wheels suddenly changes from a state where a negative torque is applied to a state where a positive torque is applied. If such a torque fluctuation occurs in a state where the lock-up clutch is completely engaged, the torque fluctuation is transmitted to the vehicle body as it is and may be felt as a shock. Conventionally, in order to solve such inconvenience, in the invention described in Japanese Utility Model Laid-Open No. 5-27249, the lock-up clutch is controlled to a half-clutch state immediately before the engine speed decreases to the return speed, The torque fluctuation is absorbed by the slip in the lock-up clutch.

[0005]

The above-described fuel cut control is executed when the throttle valve is closed and the engine speed is equal to or higher than a predetermined speed in a normal operation state in which the engine is warmed up. You. Specifically, the supply of fuel is stopped based on the fact that the throttle opening is closed to approximately the idle opening or the accelerator pedal is returned. Therefore, the operating state of the engine is forcibly rotated by the external force from the driving state in which power has been output to the driven state. Therefore, the state of operation of the torque in the power system changes due to the execution of the fuel cut control, which may cause a shock or vibration.

In the invention described in the above-mentioned publication, the lock-up clutch is controlled to the half-clutch state when returning from the fuel cut control. However, if the transmission torque capacity of the lock-up clutch is reduced, the engine is operated. Since the forcible force to rotate is reduced and the engine speed is reduced, the return from the fuel cut control is accelerated and the fuel cut period is shortened, and at the start of the fuel cut control, such a lock-up clutch is not activated. When the control in the release direction is performed, the engine speed may be reduced, and a situation may occur in which the fuel cut control that is originally to be performed cannot be performed. As described above, the invention described in the above-mentioned publication relates to control at the time of return from the fuel cut control, and there is a problem in practical use when the fuel cut control is started when the fuel cut control is started.

The present invention has been made in view of the technical problem described above, and has as its object to provide a control device capable of avoiding shocks, vibrations, and the like when starting fuel cut control. It is assumed that.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a first aspect of the present invention is a control apparatus for an internal combustion engine which performs fuel cut control for stopping supply of fuel to the internal combustion engine during running. In the case where the execution of the fuel cut control is determined, immediately before the execution of the fuel cut control, immediately before the fuel cut for controlling the torque from the internal combustion engine toward the drive wheels in the power system from the internal combustion engine to the drive wheels in a decreasing direction, Control means for controlling the torque in the power system from the internal combustion engine to the drive wheels in the power system from the internal combustion engine to the drive wheels in an increasing direction immediately after the execution of the fuel cut control; A control device comprising at least one of means immediately after and a control means. That.

Therefore, according to the first aspect of the present invention, when it is determined that the fuel cut control for stopping the supply of fuel to the internal combustion engine is performed during traveling, the drive from the internal combustion engine is performed immediately before the execution of the fuel cut control. The torque directed to the wheels is reduced. As a result, when the output torque of the internal combustion engine decreases with the execution of the fuel cut control, the torque directed to the drive wheels has already been reduced to some extent, and the torque associated with the execution of the fuel cut control is reduced. When the decrease occurs, the change width of the torque of the drive wheel becomes small. Further, when the fuel cut control means is provided, the control for increasing the torque directed to the drive wheels in the power system is performed immediately after the execution of the fuel cut control, so that the output torque of the internal combustion engine is reduced. The increase in torque by the control unit immediately after fuel cut offsets the amount of change in torque, and as a result, even if the output torque of the internal combustion engine decreases with the execution of fuel cut control, the change in torque in the drive wheels and the power system. The width becomes smaller.

The control means for immediately before the fuel cut which causes such an operation can be means for reducing the amount of intake air to the internal combustion engine, and the control immediately after the fuel cut. Means are
Means for increasing the intake air amount to the internal combustion engine may be provided.

Further, as means for reducing or increasing the amount of intake air, a throttle valve may be employed.

Alternatively, as means for decreasing or increasing the amount of intake air, the opening degree of another valve for controlling the amount of air to be taken in bypassing the throttle valve may be controlled. Means for reducing can be employed. One example of the other valve is an idle speed control valve.

Therefore, according to the second to fourth aspects of the present invention, the amount of air taken into the internal combustion engine as an air-fuel mixture immediately before the execution of the fuel cut control is reduced, so that the output torque of the internal combustion engine is reduced. descend. By executing the fuel cut control in that state, even if the torque directed to the drive wheels is reduced due to the fuel cut control, the range of change in the torque is reduced. Further, when the intake air amount is controlled immediately after the execution of the fuel cut, the amount of air taken into the internal combustion engine as a single unit immediately after the execution of the fuel cut control increases. Loss decreases,
As a result, a decrease in the output torque of the internal combustion engine is suppressed,
The output torque is relatively increased. Therefore, even if the supply of fuel to the internal combustion engine is stopped, the negative work generated immediately thereafter is suppressed, and the range of change in the output torque of the internal combustion engine is reduced. That is, the range of change in torque directed to the drive wheels in the power system is reduced.

According to a fifth aspect of the present invention, in addition to the configuration of the first aspect, the internal combustion engine is a reciprocating internal combustion engine in which a piston reciprocates in a cylinder, and the cylinder interlocks with the piston. An intake valve that opens and closes an intake port of the engine, wherein the control unit immediately before fuel cut and the control unit immediately after fuel cut change the timing of closing the intake valve in a direction in which the amount of intake air in the cylinder decreases. A control device characterized by the following.

The "means for changing the intake air amount in the cylinder in a decreasing direction" according to the fifth aspect of the invention is, for example, a means for delaying the valve closing timing when the intake valve closes after the intake bottom dead center. If the intake valve closes before the intake bottom dead center, the valve closing timing is advanced. Therefore, according to the fifth aspect of the invention, the timing of closing the intake valve immediately before the fuel cut control is executed is relatively delayed when the intake valve is closed after the intake bottom dead center, so that the intake valve is sucked into the cylinder. When a part of the drawn air is pushed back from the intake port and discharged from the cylinder, and when the valve is closed before the intake bottom dead center, it is advanced to interrupt the intake of air, and as a result, In any case, since the amount of air substantially sucked into the cylinder decreases, the output torque of the internal combustion engine decreases. As a result, the torque directed to the drive wheels in the power system immediately before the execution of the fuel cut control decreases, and the fuel cut control is executed in that state, so that the output torque of the internal combustion engine decreases with the execution of the fuel cut control. Even so, the range of change in torque in the drive wheels and the power system is reduced.

After the fuel cut control is executed, the closing timing of the intake valve when the fuel supply is stopped is relatively delayed when the intake valve is closed after the intake bottom dead center. When a part of the air sucked into the cylinder is pushed back from the intake port and discharged from the cylinder, the intake pipe negative pressure is weakened, and the valve is closed before the intake bottom dead center. By being advanced, the intake of air is interrupted halfway, and the intake pipe negative pressure is reduced. As a result, in any case, negative work by the internal combustion engine is suppressed. That is, a decrease in the output torque of the internal combustion engine is suppressed, and the output torque is relatively increased. Therefore, even if the supply of fuel to the internal combustion engine is stopped, the negative work generated immediately thereafter is suppressed, and the range of change in the output torque of the internal combustion engine is reduced. That is, the range of change in torque directed to the drive wheels in the power system is reduced.

According to a sixth aspect of the present invention, in addition to the configuration of the first aspect, an operating member for receiving torque from the power system is further provided, and the fuel cut immediately before control means controls the torque input to the operating member. Means for decreasing the torque of the power system by increasing, and the control means immediately after fuel cut is means for relatively increasing the torque of the power system by decreasing the torque input to the operating member. There is provided a control device.

According to a seventh aspect of the present invention, as the operating member, an auxiliary machine connected to the internal combustion engine is employed.
The control means immediately before the fuel cut may be means for increasing the drive torque of the auxiliary machine, and the control means immediately after the fuel cut may be means for reducing the drive torque of the auxiliary machine.

Therefore, according to the invention of claim 6 or 7, the torque directed from the internal combustion engine to the drive wheels is reduced by increasing the torque input to an operating member such as an auxiliary machine immediately before execution of the fuel cut control. As a result, even if the output torque of the internal combustion engine decreases with the execution of the fuel cut control, the range of change in the torque in the drive wheels and the power system decreases. Further, the torque directed from the internal combustion engine to the drive wheels is relatively increased immediately after the execution of the fuel cut control by reducing the torque input to the operating members such as the auxiliary equipment. As a result, the fuel cut control is performed. Even if the output torque of the internal combustion engine decreases with the execution, the variation width of the torque in the drive wheels and the power system becomes small.

According to an eighth aspect of the present invention, in any one of the first to seventh aspects, the power system includes a torque transmission variable mechanism for changing a torque transmission efficiency between the internal combustion engine and drive wheels. And a variable torque transmission control means for setting the variable torque transmission mechanism to a state in which the torque transmission efficiency is relatively high before and after the execution of the fuel cut control. Device.

Therefore, in the invention according to claim 8, even when the internal combustion engine and the drive wheels are more firmly connected, the fuel cut control is executed and the output torque of the internal combustion engine changes. The range of change in torque toward the drive wheels in the power system is suppressed.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described based on specific examples. The internal combustion engine according to the present invention is a power unit that outputs power by burning fuel such as a gasoline engine or a diesel engine, and is mounted on a vehicle as an example and is mainly used as a power source for traveling. It is an internal combustion engine. FIG. 8 schematically shows a power system in which an internal combustion engine (engine: E / G) 1 is used as a power source of a vehicle. The output shaft of the internal combustion engine 1 is connected to a transmission 2.

The transmission 2 shown here has a configuration in which a transmission mechanism is connected to a hydraulic transmission mechanism, and the hydraulic transmission mechanism is, for example, a torque converter 4 having a lock-up clutch 3. Have been. That is, the torque converter 4 is, as conventionally known,
A helical flow of oil generated by the pump impeller is provided to the turbine runner to rotate the turbine runner, and the flow direction of the oil returning from the turbine runner to the pump impeller is controlled by the stator,
The torque is transmitted via oil. On the other hand, the lock-up clutch 3 is provided between an input-side member to which the pump impeller is connected and an output-side member to which the turbine runner is connected. It is constituted so that it may engage and transmit torque. The control of the engagement and release is
As an example, this is performed by hydraulic pressure.

Therefore, when the lock-up clutch 3 is disengaged, torque is transmitted through the torque converter 4. However, since the torque converter 4 is configured to transmit torque through fluid, it is inevitable. Slippage does not occur, and the torque transmission efficiency does not reach 100%. On the other hand, since the lock-up clutch 3 is configured to mechanically engage and transmit the torque, the torque transmission efficiency is 100% in the fully engaged state.
%, Which is higher than the transmission efficiency of torque via the torque converter 4. That is, the torque transmission efficiency changes between high and low in accordance with the engaged / disengaged state of the lock-up clutch 3, and therefore, the lock-up clutch 3 and the torque converter 4 constitute a torque transmission variable mechanism in the present invention.

Further, the speed change mechanism is a mechanism configured to operate by an artificial operating force or by a driving force of an electrically controlled actuator to change the speed change ratio, and is a belt type or toroidal type. A continuously variable transmission mechanism or a gear type stepped transmission mechanism. In the example shown in the figure, a continuously variable transmission (CVT) 5 is employed, and the continuously changing gear ratio makes the change in the output torque accompanying the gear shift smooth, so that the rotation of the internal combustion engine 1 is increased. The lock-up clutch 3 can be maintained in the engaged state until the number of revolutions becomes considerably low.

The output shaft of the transmission 2 is connected to left and right drive wheels 7 via a propeller shaft and a final reduction gear 6. A brake (not shown) for driving torque control (traction control) or an anti-lock brake system (ABS) is attached to all wheels including the driving wheel 7 to control the driving torque in a decreasing direction. can do.

As the internal combustion engine 1, a reciprocating engine is most common. In the example shown in the figure, the supply and stop of fuel or the intake air amount and valve timing, and the driving torque of auxiliary equipment are electrically controlled. It is configured to be able to control. This will be described with reference to the drawings. In FIG. 9, a piston 9 that moves up and down inside a cylinder (cylinder) 8 is provided, and the up and down movement is changed to a rotational movement by a crank mechanism to output power. Have been. An intake port 10 and an exhaust port 11 are provided at an upper portion of the cylinder 8. The intake port 10 is opened and closed by an intake valve 12, and the exhaust port 11 is opened and closed by an exhaust valve 13. . The intake valve 12 and the exhaust valve 13 are configured to open and close according to the rotation angle of a crankshaft (not shown), that is, in conjunction with the piston 9.

The opening / closing timing, particularly the intake valve 1
Variable valve timing mechanism (VVT) that controls to relatively delay or advance the opening and closing timing of 2
14 are provided. This is, for example, the valve 1
Change the mounting phase of the cams pressing the camshafts 2 and 13 with respect to the camshafts (not shown), or the camshafts and pulleys for driving the camshafts (not shown)
The opening / closing timing is advanced or retarded by changing the relative phase of the open / close timing.

The intake pipe 1 communicating with the intake port 12 described above.
In the middle of 5, a throttle valve 16 for controlling the intake air amount is arranged. The throttle valve 16 changes the opening in response to an acceleration / deceleration request by an accelerator operation or the like. In the example shown in the figure, an electronic throttle valve 16 that is opened and closed by an electrically controlled actuator 17 is employed. ing. Therefore, in the example shown here, the throttle opening can be controlled without being based on the accelerator operation. For example, the idle speed (idle speed) can be controlled by the electronic throttle valve 16.

When the throttle valve is configured to be opened and closed only in response to an accelerator operation,
An idle speed control valve (ISC) that controls the amount of air taken in bypassing the throttle valve
A valve 18 can be provided. In that case, I
The degree of opening of the SC valve 18 is controlled by an actuator 1 such as a motor.
9 to electrically control the amount of intake air. Further, the intake port 12
A fuel injector 20 is provided in the vicinity of the fuel injection device, and is configured to inject fuel to the intake air to generate an air-fuel mixture.

The opening and closing timing of the intake valve 12 and the exhaust valve 13, the opening of the throttle valve 16, the opening of the ISC valve 18, the fuel injection amount by the fuel injector 20 and the execution / stop of the injection in the internal combustion engine 1, and An electronic control unit (E-
(ECU) 21 is provided. This electronic control unit 21
Is mainly configured with a microcomputer, is configured to perform calculations using input data or data stored in advance, and to output a predetermined control command signal. The electronic control unit 21 includes a rotation speed NE of the internal combustion engine 1, a vehicle speed and an accelerator opening (depression amount of an accelerator pedal (not shown)) Acc, a cooling water temperature of the internal combustion engine 1, and the lock-up clutch (L /
U) An engagement / disengagement (ON / OFF) signal of 3 is input as data.

A transmission electronic control unit (T) for controlling the engagement / disengagement of the lock-up clutch 3 in the transmission 2 and for controlling the speed ratio set by the continuously variable transmission mechanism 5
-ECU) 22 is provided. This electronic control unit 2
Reference numeral 2 mainly includes a microcomputer, and is configured to perform a calculation using input data or data stored in advance and output a predetermined control command signal to the transmission 2. . Specifically, a control signal for controlling the gear ratio and the engagement / disengagement of the lock-up clutch 3 is output based on the required drive amount indicated by the accelerator opening and the drive state indicated by the vehicle speed. These electronic control units 21 and 22 are connected to each other so that data communication is possible.

An output shaft (crankshaft) of the internal combustion engine 1 includes a compressor 23 for an air conditioner and an alternator 24.
Are connected via a wrapping transmission mechanism such as a belt. These auxiliary devices are driven as necessary. For example, a clutch (not shown) is provided in a power transmission system for the air conditioner compressor 23, and when a request for cooling of the vehicle compartment is made, The output torque of the internal combustion engine 1 is transmitted to the air conditioner compressor 23 by engaging the clutch to drive it. When a variable capacity air conditioner compressor 23 is used, the capacity is changed according to the required cooling amount. Therefore, by driving these accessories and changing the driving torque, the torque directed from the internal combustion engine 1 to the driving wheels 7 is increased or decreased. An electronic control unit (not shown) for controlling the auxiliary equipment is provided, and the electronic control units 2
It is connected so that data communication is possible with 1 and 22.

In order to reduce the fuel consumed by the internal combustion engine 1, a system for executing fuel cut control for temporarily stopping the supply of fuel when a predetermined condition is satisfied during traveling is provided. I have. Specifically, it is configured to determine that the electronic control device 21 performs the fuel cut control, and to stop supplying the fuel from the fuel injector 20 by a command signal based on the determination result. I have. The execution of the fuel cut control is determined, for example, in a state where the warm-up of the internal combustion engine 1 is completed, the cooling water temperature is equal to or higher than a predetermined temperature, and the rotational speed NE of the internal combustion engine 1 is equal to or higher than the predetermined rotational speed. This is performed when the accelerator opening becomes zero. Then, as the vehicle speed decreases, the internal combustion engine 1
The fuel supply is restarted when the number of revolutions decreases below the predetermined return number of revolutions.

By executing the fuel cut control, the output torque of the internal combustion engine 1 is reduced. Therefore, when the torque transmission rate of the power system from the internal combustion engine 1 to the drive wheels 7 is high, that is, the lock-up is performed. Clutch 3
Is engaged and the connection between the internal combustion engine 1 and the driving wheels 7 is in a so-called rigid state, the execution of the fuel cut control causes a sudden change in the driving torque, which may cause a shock. Therefore, the aforementioned internal combustion engine 1
The control device according to the present invention, which mainly includes the electronic control device 22 for the vehicle, is configured to execute the following control immediately before or immediately after the execution of the fuel cut control.

FIG. 1 is a flowchart showing a control example of the electronic throttle valve 1.
6 is intended for the internal combustion engine 1 configured to control the idle speed. The routine shown in the flowchart of FIG. 1 is executed every predetermined time (several tens of microseconds) Δt. Describing the control example shown in FIG. 1 specifically, first, it is determined whether or not the idle switch is ON (step S1). This idle switch is a switch that is turned on when the accelerator pedal is returned, that is, when the depressed amount of the accelerator pedal becomes zero. Therefore, in step S1, it is determined whether or not the engine is idling.

If the result of the determination in step S1 is affirmative because the idle switch is on, the opening which is the amount of intake air required to maintain the idle speed, ie, the idle speed control opening θisc, is determined by the electronic control unit. The temporary target opening θtt of the throttle valve 16 is set (step S2). Note that the idle speed control opening degree θisc is a value obtained by updating a preset value or a default value by learning control.

Next, it is determined whether or not the flag before execution of the fuel cut control is ON (step S3). That is, it is determined whether or not it is immediately before the supply of fuel to the running internal combustion engine 1 is stopped. As described above, the fuel cut control is executed when other conditions are satisfied other than the return of the accelerator pedal. Therefore, when any of those conditions is not satisfied, it is determined that the fuel cut control is to be executed. Is not performed, the fuel cut pre-execution flag is not turned ON. Also, such as when fuel cut control has already been executed,
If the state is not immediately before the execution of the fuel cut control, the pre-fuel cut execution flag is not set to ON.

When it is determined that the fuel cut control is to be executed and the control has not been executed yet, and the determination in step S3 is affirmative, it is determined whether the lockup flag is ON. (Step S
4). The lock-up flag is turned on when the lock-up clutch 3 is in the engaged state, that is, when the internal combustion engine 1 and the drive wheels 7 are rigidly connected and the torque transmission efficiency in the drive system is high. The flag is switched ON / OFF by a predetermined routine executed by the transmission electronic control unit 22.

If a positive determination is made in step S4 because the lock-up clutch 3 is engaged,
Temporary target throttle opening θtt of electronic throttle valve 16
The lock-up ON fuel cut execution pre-execution opening θfcp is set (step S5). The opening θfcp before the execution of the fuel cut when the lock-up is ON is an opening (θfcp <θisc) smaller than the above-mentioned idle speed control opening θisc, and is therefore an opening for reducing the intake air amount from idling. The provisional target throttle opening θtt set in this way is the target throttle opening θ
t (step S6), and the opening of the electronic throttle valve 16 is controlled so as to become the target opening θt. Therefore, after the determination of the execution of the fuel cut control is established, and immediately before the execution, the throttle opening is smaller than the opening that maintains the idle speed on condition that the lock-up clutch 3 is engaged. It is narrowed down to degrees. As a result, the amount of intake air in a state in which fuel is supplied to the internal combustion engine 1 decreases, so that the output torque of the internal combustion engine 1 decreases.

In the state immediately before the execution of the fuel cut control, the above-described processes from step S1 to step S6 are executed at predetermined time intervals Δt, and the state in which the intake air amount is reduced, that is, the output torque of the internal combustion engine 1 is reduced. State is continued. Then, when the fuel cut control is executed after a predetermined time has elapsed since the determination of the execution of the fuel cut control is established, the above-described fuel cut pre-execution flag is turned OFF. Is determined. In this case, step S4
And skip step S5 and proceed to step S6.
Since the idle speed control opening θisc is set as the temporary target throttle opening θtt, this is set as the target throttle opening θt, and control is performed so that the actual throttle opening becomes the target opening θt. That is, the throttle opening is increased to an opening that maintains the normal idle speed. Therefore, in the internal combustion engine 1,
Since air intake and exhaust occur while the fuel supply is stopped, a torque associated with a so-called pumping loss is generated as a braking torque (engine brake torque).

FIG. 2 shows a change in the output torque TE of the internal combustion engine 1 when the intake air amount is controlled to decrease as described above immediately before the execution of the fuel cut control. That is, when the accelerator opening Acc becomes zero at the time point t0, the fueling is performed at that time on the condition that the warm-up of the internal combustion engine 1 has been completed and the rotational speed NE of the internal combustion engine 1 is equal to or higher than a predetermined rotational speed. The flag before cutting is O
N. As a result, the throttle opening is locked up O
Set the opening θfcp before executing fuel cut at N to the target opening θt
The output torque TE of the internal combustion engine 1
Is smaller than the idling torque shown by the broken line in FIG.

Then, at a time point t1 when a predetermined time has elapsed from the establishment of the fuel cut control determination, the fuel cut control is executed, the supply of fuel to the internal combustion engine 1 is stopped, and at the same time, the throttle opening is reduced to the idle speed control opening θisc. The target is controlled. As a result, the output torque TE of the internal combustion engine 1 becomes a negative torque rotated by the traveling inertia of the vehicle.

Therefore, according to the above control, when executing the fuel cut control, the output torque TE of the internal combustion engine 1 is previously reduced to a torque lower than the idling torque, and the fuel supply is stopped in that state. Internal combustion engine 1
Output torque TE further decreases (increases in the negative direction), so that the change width of the torque from the internal combustion engine 1 to the drive wheels 7 in the power system described above decreases. This will be described with reference to FIG. 2. If the above-described intake air amount reduction control is not executed, the output torque during idling indicated by the broken line in FIG. 2 decreases to the torque during fuel cut control. When the intake air amount reduction control is executed, the torque is reduced from the torque smaller than the output torque during idling to the torque during fuel cut control. The change width of the torque becomes small. As a result, the torque fluctuation accompanying the execution of the fuel cut control is suppressed, and the shock can be reduced or prevented.

If the result of the determination in step 4 is negative due to the disengagement of the lock-up clutch 3, the process immediately proceeds to step S6, in which the control for decreasing the output torque of the internal combustion engine 1, ie, the throttle opening, is performed. Does not execute the control to temporarily reduce the When the lock-up clutch 3 is released, the torque transmission efficiency of the power system described above is low, so that the inertia force of the vehicle is not sufficiently transmitted to the internal combustion engine 1 and the rotation speed of the internal combustion engine 1 decreases. This is because in extreme cases, engine stall may occur.

Further, if the determination is negative in step S1 because the vehicle is not idling, normal throttle opening control is executed (step S7). That is, the throttle opening is obtained based on the output target torque, the rotation speed of the internal combustion engine (engine rotation speed), and the like, and this is set as the temporary target throttle opening θtt. Thereafter, the process proceeds to step S6.

Although the above control example is directed to the internal combustion engine 1 configured to control the idle speed by the electronic throttle valve 16, the idle speed is controlled by the above-described ISC valve 18. In the internal combustion engine 1 configured as described above, the reduction control of the intake air amount immediately before the execution of the fuel cut control is performed by the ISC
This is performed by temporarily reducing the opening of the valve 18.
The control is represented by, for example, a control routine in which the throttle opening in the control example shown in FIG. 1 is replaced with the ISC valve opening.

The control for temporarily reducing the output torque by reducing the amount of intake air is performed by reducing the opening degree of the electronic throttle valve 16 and the ISC valve 18 as well as by controlling the closing timing of the intake valve 12. This can also be performed by making the valve closing timing different from idling.
FIG. 3 is a flowchart showing an example of the control.

The routine shown in FIG.
This is executed every t, and it is first determined whether or not the idle switch is ON (step S11). This is control similar to step S1 shown in FIG. If it is determined that the idling state is affirmative in step S11, the idling valve timing Tvi is set as the provisional target valve timing Tvtt (step S1).
2). The idling valve timing Tvi is a timing predetermined in relation to the crank angle, that is, the stroke position of the piston 9.

Next, it is sequentially determined whether the fuel cut pre-execution flag is ON (step S13) and whether the lock-up flag is ON (step S14). These determinations are made in step S3 shown in FIG.
And it is the same as the determination process of step S4, respectively.
If a positive determination is made in these steps S13 and S14, the valve timing Tvfcp before the execution of the fuel cut at lock-up ON is set as the temporary target valve timing Tvtt (step S15). The valve timing Tvfcp before execution of the fuel cut when the lock-up is ON is determined when the variable valve timing mechanism 14 that controls the closing timing of the intake valve 12 after the piston 9 reaches the intake bottom dead center is used. This is a timing delayed from the valve closing timing during idling. In addition, the intake valve 1 before the piston 9 reaches the intake bottom dead center.
Variable valve timing mechanism 14 for controlling valve closing timing of 2
Is used, the valve timing Tvfcp before execution of fuel cut at lock-up ON is earlier than the valve closing timing at idling.

Therefore, in the former case, part of the air once sucked into the cylinder 8 is pushed back from the intake port 10 by the rise of the piston 9, so that the cylinder 8
The amount of air substantially sucked into the interior is reduced. In the latter case, since the intake valve 12 closes early before the piston 9 reaches the bottom dead center, the amount of air taken into the cylinder 8 is limited and reduced.

The provisional target valve timing Tvtt set in this way is set as the target valve timing Tvt (step S16), and the actual closing timing of the intake valve 12 matches the target valve timing Tvt. The variable valve timing mechanism 14 is controlled. As a result, the actual intake air amount immediately before the execution of the fuel cut control decreases, and the output torque of the internal combustion engine 1 decreases.

In a state immediately before the execution of the fuel cut control, the above-described processes from step S11 to step S16 are executed at predetermined time intervals Δt.
The state in which the amount of air entering inside, that is, the state in which the output torque of the internal combustion engine 1 is reduced, is continued. When the fuel cut control is executed after a predetermined period of time has elapsed since the determination of the execution of the fuel cut control is made, the above-described fuel cut pre-execution flag is turned off. Is determined. In this case, the process skips steps S14 and S15 and proceeds to step S16. However, since the idling valve timing Tvi is set as the temporary target valve timing Tvtt, this is set as the target valve timing Tvt, and the actual valve timing is set to the target valve timing Tvt. Control is performed so as to reach the target timing Tvt. Therefore, in the internal combustion engine 1, air intake and exhaust occur while the fuel supply is stopped, so that a torque associated with a so-called pumping loss is generated as a braking torque (engine brake torque).

Even when the closing timing of the intake valve 12 is controlled as described above, the air amount in the cylinder 8 is
Since the output is less than at the time of idling, the fuel cut control is executed in a state where the output torque of the internal combustion engine 1 is reduced. As a result, the output torque of the internal combustion engine 1 is reduced due to the execution of the fuel cut control. But,
This occurs in a state of lower torque than at the time of idling, and eventually the range of change in torque from the internal combustion engine 1 to the drive wheels 7 in the power system becomes smaller. Therefore, shocks and vibrations are suppressed or prevented.

If the lock-up clutch 3 is disengaged and a negative determination is made in step S14, the control immediately proceeds to step S16 without performing the control to change the closing timing of the intake valve 12. . this is,
This is the same as the case where a negative determination is made in step S4 in the control example shown in FIG. If the determination is negative in step S11 because the vehicle is not idling, the normal valve timing is set. That is, a map value of the valve timing according to the output target torque, the engine speed, and the like is read and set as the provisional target valve timing Tvtt (step S1).
7). Thereafter, the process proceeds to step S16.

Each of the above-described control examples is configured to reduce the output torque of the internal combustion engine 1 immediately before executing the fuel cut control, thereby reducing the change width of the torque when the fuel cut control is executed. However, instead of this control or in addition to this control, the output torque of the internal combustion engine 1 immediately after the execution of the fuel cut control is temporarily increased relatively (by reducing the negative torque),
The change width of the torque accompanying the execution of the fuel cut control may be suppressed. A control example immediately after the execution of the fuel cut control will be described below.

FIG. 4 is a flowchart showing an example of the control. The example of the control shown in FIG.
6 is intended for the internal combustion engine 1 configured to control the idle speed. The routine shown in the flowchart of FIG. 4 is executed every predetermined time (several tens of microseconds) Δt. In the control example shown in FIG. 4, first, it is determined whether or not the idle switch is ON (step S21). This is a process for determining whether or not the vehicle is idling. Step S1 shown in FIG.
Alternatively, it is a process similar to step S11 shown in FIG.

When the engine is in the idling state, that is, when the idle switch is on, the flow goes to step S21.
Is positive, the opening which is the intake air amount necessary to maintain the idle speed, that is, the idle speed control opening θisc is set as the provisional target opening θtt of the electronic throttle valve 16. (Step S22). Note that the idle speed control opening degree θisc is a value obtained by updating a preset value or a default value by learning control.

Next, it is determined whether or not a flag indicating that the fuel cut control is being executed while the lock-up clutch 3 is engaged (a lock-up ON fuel cut execution flag) is ON (see FIG. 4). Step S2
3). As described above, when the lock-up clutch 3 is engaged and the rotation speed of the internal combustion engine 1 is maintained at or above the predetermined rotation speed during deceleration in a state where the warm-up is completed,
Fuel cut control for stopping supply of fuel to the internal combustion engine 1 is executed. This state corresponds to the internal combustion engine 1 described above.
Electronic control unit 21 for transmission and electronic control unit 22 for transmission
And the flag is set to ON or OFF according to the result of the determination.

When the fuel cut control is executed while the lock-up clutch 3 is ON and the above flag is turned ON, or when the fuel cut control is executed and the above flag is turned ON, that is, in step S23. If the determination is affirmative, it is determined whether the count time Cfc of a counter (fuel cut continuation counter) that measures the elapsed time after the start of the fuel cut control is shorter than a predetermined time (set time) α. (Step S24). If an affirmative determination is made in step S24, the elapsed time since the start of the fuel cut control is short, and the state is immediately after the start of the fuel cut control.
Lock-up O as the provisional target throttle opening θtt of 6
The opening θfca is set after the N-time fuel cut is executed (step S25). The opening θfca after execution of the fuel cut when the lock-up is ON is larger than the above-mentioned idle speed control opening θisc (θfca> θis
c), and therefore, the opening to increase the intake air amount more than at the time of idling. The provisional target throttle opening θtt set in this way is set as the target throttle opening θt (step S26), and the opening of the electronic throttle valve 16 is controlled so as to become the target opening θt.

Therefore, immediately after the fuel cut control is started, the throttle opening is set to be larger than the opening for maintaining the idle speed on condition that the lock-up clutch 3 is engaged. ,
In a state where no fuel is supplied, the resistance to the airflow sucked by the internal combustion engine 1 is reduced, and the inside of the cylinder 8 is suppressed from becoming a large negative pressure. That is, an increase in negative torque (braking torque) due to the pumping loss of the internal combustion engine 1 is suppressed, and the output torque of the internal combustion engine 1 becomes relatively large. In other words, the decrease amount of the output torque of the internal combustion engine 1 due to the execution of the fuel cut control becomes small, and the change width of the torque toward the drive wheels 7 in the power system from the internal combustion engine 1 to the drive wheels 7 becomes small. Accordingly, shock and vibration are suppressed or prevented.

Immediately after the fuel cut control is started, the above-described processes from step S21 to step S26 are executed at predetermined time intervals Δt, and the state in which the intake air amount is increased, that is, the output torque of the internal combustion engine 1 is reduced. The state which is gradually increased is continued. When the predetermined time α has elapsed from the start of the fuel cut control, the time Cfc measured by the counter reaches the set time α, and a negative determination is made in step S24. In this case, the process skips step S25 and proceeds to step S26, in which the idle speed control opening θisc previously set as the provisional target throttle opening θtt in step S22 is set as the target throttle opening θt. That is, the throttle opening that has been relatively increased for a predetermined time after the start of the fuel cut control is reduced to the opening that maintains the idle speed. As a result, since the intake of air by the internal combustion engine 1 is restricted, the pump ping loss increases, and the so-called engine braking force is set to a desired magnitude.

FIG. 5 shows a change in the output torque TE of the internal combustion engine 1 when the intake air amount is controlled to increase as described above immediately after the start of the fuel cut control. That is, when the accelerator opening Acc becomes zero at time t10, the fuel cut is executed on condition that the warming-up of the internal combustion engine 1 has been completed and the rotational speed NE of the internal combustion engine 1 is equal to or higher than a predetermined rotational speed. The judgment is made. At time t11 when a predetermined time has elapsed from that time, the fuel cut control is executed. At the same time, the lock-up ON fuel cut execution flag is turned ON, and the counter Cfc
Starts counting time. Further, the opening θfca after execution of the fuel cut at lock-up ON described above is set as the target throttle opening θt. In this case, the output torque TE of the internal combustion engine 1 decreases with the execution of the fuel cut control. However, by setting the throttle opening to be larger than the opening that maintains the idle speed, the output torque TE becomes relatively small. In other words, the increase in the negative torque is suppressed, and the torque shown by the solid line in FIG. 5 is obtained. On the other hand, when the opening is set to maintain the idle speed, the torque shown by the broken line in FIG. 5 becomes the torque shown in FIG. Is suppressed or prevented.

Then, while the throttle opening is in the predetermined time α, the opening θ after executing the fuel cut when the lock-up is ON is performed.
fca, and the throttle opening becomes the idle speed control opening θ at time t12 when the predetermined time α has elapsed.
The negative opening torque of the internal combustion engine 1 increases by controlling the isc as the target opening and the throttle opening is reduced, that is, the output torque TE decreases. As a result, the expected engine brake torque is generated.

If the fuel cut control execution condition is not satisfied and the fuel cut control is not being executed even in the idling state, a negative determination is made in step S23. In this case, the process immediately proceeds to step S26, and the control for relatively increasing the output torque of the internal combustion engine 1, that is, the control for temporarily increasing the throttle opening is not executed. This is to avoid an increase in output torque due to an increase in the amount of intake air since the supply of fuel is continued.

Further, if the determination is negative in step S1 because the vehicle is not in the idling state, the control of the normal throttle opening is executed (step S27).
That is, the throttle opening is obtained based on the output target torque, the rotation speed of the internal combustion engine (engine rotation speed), and the like, and this is set as the temporary target throttle opening θtt. Thereafter, the process proceeds to step S26.

The control example shown in FIG. 4 is an example in which the idle speed is controlled by the electronic throttle valve 16, but the idle speed is controlled by the ISC valve 18. In the internal combustion engine 1 configured to be controlled by
The control for increasing the intake air amount immediately after the execution of the fuel cut control is executed by temporarily increasing the opening of the ISC valve 18. The control is represented by, for example, a control routine in which the throttle opening in the control example shown in FIG. 4 is replaced with the ISC valve opening.

The amount of air sucked into the cylinder 8 is controlled not only by the throttle valve 16 and the ISC valve 18 provided upstream of the intake port 10 but also by changing the closing timing of the intake valve 12. What can be done is as described above. Therefore, the control for relatively increasing the output torque TE of the internal combustion engine 1 during the predetermined time α immediately after the execution of the fuel cut control can be controlled by changing the closing timing of the intake valve 12. This control is similar to the control shown in FIG. 3 described above, and this will be described with reference to FIG.

The routine shown in FIG. 6 is executed for a predetermined short time Δ
This is executed every t, and it is first determined whether or not the idle switch is ON (step S31). This is the same control as step S1 shown in FIG. 1 or step S11 shown in FIG. If the determination is positive in step S31 because the vehicle is in the idling state, the idling valve timing Tvi is set as the provisional target valve timing Tvtt (step S32). This is the same control as in step S12 shown in FIG.

Next, it is determined whether or not a flag indicating that the fuel cut control is being executed in a state where the lock-up clutch 3 is engaged (a lock-up ON-time fuel cut execution flag) is ON (see FIG. 4). Step S3
3). This is the same control as in step S23 shown in FIG. 4 described above.

When the fuel cut control is executed while the lock-up clutch 3 is ON and the above flag is turned ON, or when the fuel cut control is executed and the above flag is turned ON, that is, in step S33, If the determination is affirmative, it is determined whether the count time Cfc of a counter (fuel cut continuation counter) that measures the elapsed time after the start of the fuel cut control is shorter than a predetermined time (set time) α. (Step S34). This corresponds to step S2 shown in FIG.
This is the same control as in No. 4.

If the determination in step S34 is affirmative, the elapsed time since the start of the fuel cut control is short, and the state is immediately after the start of the fuel cut control. The valve timing Tvfca after execution of the fuel cut at lock-up ON is set as the target valve timing Tvtt (step S3).
5). The valve timing Tvfca after execution of the fuel cut when the lock-up is ON is performed when the variable valve timing mechanism 14 that controls the closing timing of the intake valve 12 after the piston 9 reaches the intake bottom dead center is used. This is a timing delayed from the valve closing timing during idling. Further, when the variable valve timing mechanism 14 that controls the closing timing of the intake valve 12 before the piston 9 reaches the intake bottom dead center is used, the valve timing Tvfca after execution of the fuel cut at lock-up ON is , Which is earlier than the valve closing time during idling.

The provisional target valve timing Tvtt set in this way is set as the target valve timing Tvt (step S36), and the actual valve closing timing of the intake valve 12 matches the target valve timing Tvt. The variable valve timing mechanism 14 is controlled. Therefore, in the former case in which the closing timing of the intake valve 12 is delayed, part of the air once sucked into the cylinder 8 is pushed back from the intake port 10 by the rise of the piston 9, and the closing of the intake valve 12 In the latter case, the amount of air sucked into the cylinder 8 itself is suppressed, so that the cylinder 9
The amount of air sucked into the air and compressed is reduced. As a result, negative torque due to pumping loss is reduced. That is, since the output torque of the internal combustion engine 1 is relatively increased, similarly to the control example shown in FIG. 4, the width of change of the torque accompanying the execution of the fuel cut control is reduced, and the shock and vibration are suppressed or prevented. Is done.

Since the fuel cut execution flag at lock-up ON is OFF, step S3 is executed.
When the determination is negative in step S3 and when the determination in step S34 is negative due to the lapse of a predetermined time α or more from the start of the fuel cut control,
The process proceeds to step S36 after skipping step S35, and setting the idling valve timing Tvi to the target valve timing Tvt, as in the control example shown in FIG.
Further, since the vehicle is not in the idling state, step S3
If a negative determination is made in step 1, a map value of the valve timing corresponding to the output target torque, the engine speed, and the like is read and set as the provisional target valve timing Tvtt (step S37), and thereafter, step S3
Going to 6 is the same as the control example shown in FIG.

Incidentally, since the vibration and shock of the vehicle are caused by a sudden change in the driving torque of the drive wheels 7, in order to prevent or suppress the vibration and shock,
The amount of change in the driving torque per unit time may be reduced. In each of the specific examples described above, the torque directed to the drive wheels 7 in the drive system is controlled to be large or small by controlling the substantial intake air amount of the internal combustion engine 1 as the power source. On the other hand, it is also possible to control the torque directed to the drive wheels 7 in the power system by changing the torque received by members other than the internal combustion engine 1 that absorb torque in the power system. it can.
Hereinafter, an example thereof will be described.

The example shown in FIG. 7 is a control example using a variable capacity air conditioner compressor 23 which is an auxiliary machine as an example of an operating member. First, it is determined whether or not the fuel cut pre-execution flag is ON (step S41). This corresponds to step S3 shown in FIG. 1 or step S3 shown in FIG.
This is a determination process similar to that of FIG. If the determination of the fuel cut control is established and the state is before the execution of the control, and the determination in step S41 is affirmative, the increase Pacp before the execution of the fuel cut is set as the air conditioner discharge increase / decrease Pac. (Step S42). This can be performed, for example, by an electronic control unit for an air conditioner.

On the other hand, the basic air conditioner discharge amount Pb is set by a normal process (step S43). In particular,
A value obtained by multiplying the deviation between the room temperature tr and the set temperature tt by a predetermined coefficient K, a value F (to) determined based on the outside temperature to,
As a sum with a value G (h) determined based on the sunshine intensity h,
The basic air conditioner discharge amount Pb is calculated. The final air conditioner discharge amount P is obtained by adding the air conditioner discharge increase amount Pac to the basic air conditioner discharge amount Pb (step S).
44).

Therefore, immediately before the start of the fuel cut control, the driving torque of the compressor 23 for the air conditioner, that is, the torque input from the internal combustion engine 1 to the compressor 23 for the air conditioner increases, and accordingly, the driving wheels 7 from the internal combustion engine 1 via the transmission 2 The torque directed to is reduced.
Therefore, even if the output torque TE of the internal combustion engine 1 decreases due to the execution of the fuel cut control, since the torque in the power system from the internal combustion engine 1 to the drive wheels 7 has already been reduced, the variation range of the drive torque is small. As a result, shocks and vibrations are suppressed or prevented.

On the other hand, the flag before fuel cut execution is set to O
If the determination is negative in step S1 due to the FF, it is determined whether the lock-up ON fuel cut execution flag is ON (step S4).
5). That is, it is determined whether or not the fuel cut control has already been executed, or whether or not the fuel cut control has been started. This is the same determination as in step S23 shown in FIG.

If the fuel cut control has already been started, the flag is ON, so that the determination in step S45 is affirmative. In this case, the count time Cfc of the fuel cut continuation counter is equal to the set time α.
It is determined whether it is less than (Step S46). That is, it is determined whether the fuel cut control has just been started. This is a determination step similar to step S24 shown in FIG. If an affirmative determination is made in step S46, this is a state immediately after the start of the fuel cut control, and the post-fuel cut decrease Paca is set as the air conditioner discharge amount increase / decrease Pac (step S46).
47). This can be performed, for example, by an electronic control unit for an air conditioner.

Thereafter, the routine proceeds to steps S43 and S44 described above, where the basic air-conditioner discharge amount Pb is calculated, and the basic air-conditioner discharge amount Pb is added to the fuel-cut reduction amount Paca. That is, the final air-conditioner discharge amount P is obtained by subtracting the reduced amount Paca after the fuel cut from the basic air-conditioner discharge amount Pb.

Therefore, immediately after the start of the fuel cut control, the driving torque of the compressor 23 for the air conditioner, that is, the torque input from the internal combustion engine 1 to the compressor 23 for the air conditioner decreases. 7 is relatively increased. For this reason, even if the output torque TE of the internal combustion engine 1 decreases due to the execution of the fuel cut control, the decrease in the torque in the power system from the internal combustion engine 1 to the drive wheels 7 is suppressed, so that the variation range of the drive torque decreases. ,
As a result, shock or vibration is suppressed or prevented.

If a negative determination is made in step S45, the determination to execute the fuel cut control has not been established, and the control has not been performed. Therefore, in this case, the air conditioner discharge increase / decrease Pac is set to "0" (step S48), and thereafter, the process proceeds to step S43. Similarly, when the time equal to or longer than the set time α has elapsed after the start of the fuel cut control, that is, when the determination in step S46 is affirmative, the normal fuel cut control is executed. Since it is necessary to generate the engine brake torque of the period, the process proceeds to step S48, and the air conditioner discharge increase / decrease Pac is set to “0”. The above-described control device according to the present invention is particularly effective when the fuel cut control is executed by engaging the lock-up clutch 3 up to a low vehicle speed in a vehicle equipped with a continuously variable transmission.

Here, the relationship between the present invention and each of the above-described specific examples will be described. Functional means of steps S5 and S6 shown in FIG. 1, functional means of steps S15 and S16 shown in FIG. 3, and FIG. The functional means of steps S42 and S44 correspond to the fuel cut immediately before control means of the present invention, and the functional means of steps S35 and S36 shown in FIG. 6 and the functional means of steps S47 and S44 shown in FIG. This corresponds to the control means immediately after fuel cut of the present invention.

In the specific example described above, the torque in the power system is reduced by changing the amount of intake air to the internal combustion engine 1 during idling or by increasing the load on the internal combustion engine 1 by the compressor 23 for the air conditioner. Alternatively, or in addition to this, the fuel cut is made by increasing the torque absorbed by the motor generator in the hybrid vehicle, or by generating a braking force by an anti-lock brake system. The torque of the drive system immediately before the execution of the control may be reduced. The control for temporarily increasing the torque of the drive system immediately after the start of the fuel cut control may be performed by applying a torque by a motor or a motor generator in a hybrid vehicle. Further, the auxiliary device in the present invention is not limited to the above-described variable displacement air conditioner compressor, but may be another device such as an alternator or a power steering oil pump. In the above specific example, FIGS.
Are individually described, but these controls may be performed in parallel within a range where mutual interference does not occur.

[0086]

As described above, according to the first aspect of the present invention, when it is determined that the fuel cut control for stopping the supply of fuel to the internal combustion engine is performed during traveling, the fuel cut control is executed. Immediately before the execution, the torque directed from the internal combustion engine to the drive wheels is reduced.Therefore, when the output torque of the internal combustion engine is reduced due to the execution of the fuel cut control, the torque directed to the drive wheels is already at a certain level. Therefore, when the torque is reduced due to the execution of the fuel cut control, the range of change in the torque of the drive wheels is reduced. Further, when the fuel cut control means is provided, the control for increasing the torque directed to the drive wheels in the power system is performed immediately after the execution of the fuel cut control, so that the output torque of the internal combustion engine is reduced. The increase in torque by the control unit immediately after fuel cut offsets the amount of change in torque, and as a result, even if the output torque of the internal combustion engine decreases with the execution of fuel cut control, the change in torque in the drive wheels and the power system. The width becomes smaller. As a result, it is possible to suppress or prevent shocks and vibrations caused by executing the fuel cut control.

According to each of the second to fourth aspects of the present invention, the amount of air taken into the internal combustion engine as an air-fuel mixture immediately before the fuel cut control is executed is reduced, so that the output torque of the internal combustion engine is reduced. Is reduced, and the fuel cut control is executed in that state, so that even if the torque directed to the drive wheels decreases due to the fuel cut control,
The change width of the torque becomes small. Further, when the intake air amount is controlled immediately after the execution of the fuel cut, the amount of air taken into the internal combustion engine as a single unit immediately after the execution of the fuel cut control increases. Loss is reduced,
A decrease in the output torque of the internal combustion engine is suppressed, and the output torque is relatively increased. Therefore, even if the supply of fuel to the internal combustion engine is stopped, the negative work generated immediately thereafter is suppressed, and the range of change in the output torque of the internal combustion engine is reduced. That is, the range of change in torque directed to the drive wheels in the power system is reduced. As a result, it is possible to suppress or prevent shocks and vibrations caused by executing the fuel cut control.

Further, according to the fifth aspect of the invention, immediately before the fuel cut control is executed, the closing timing of the intake valve is relatively delayed when the intake valve closes after the intake bottom dead center. As a result, a part of the air sucked into the cylinder is pushed back from the intake port and discharged from the cylinder, and when the valve is closed before the intake bottom dead center, the air is advanced due to the advancement of the air. As a result, in any case, the amount of air substantially sucked into the cylinder decreases, so that the output torque of the internal combustion engine decreases.
As a result, the torque directed to the drive wheels in the power system immediately before the execution of the fuel cut control decreases, and the fuel cut control is executed in that state, so that the output torque of the internal combustion engine decreases with the execution of the fuel cut control. Even so, the range of change in torque in the drive wheels and the power system is reduced.

According to the fifth aspect of the present invention, after the fuel cut control is executed, when the intake valve closes after the intake bottom dead center while the fuel supply is stopped. The intake pipe negative pressure is weakened by a part of the air sucked into the cylinder being pushed back from the intake port and being discharged from the cylinder by being relatively delayed, and before the intake bottom dead center. When the valve is closed, advancement of the angle causes the air intake to be interrupted halfway, weakening the intake pipe negative pressure. As a result, in any case, the negative work by the internal combustion engine is suppressed. Is done. That is, a decrease in the output torque of the internal combustion engine is suppressed, and the output torque is relatively increased. Therefore, even if the supply of fuel to the internal combustion engine is stopped, the negative work generated immediately thereafter is suppressed, and the range of change in the output torque of the internal combustion engine is reduced. That is, the range of change in torque directed to the drive wheels in the power system is reduced. Therefore, in any case, it is possible to suppress or prevent shocks and vibrations caused by executing the fuel cut control.

Further, according to the invention of claim 6 or 7, the torque directed from the internal combustion engine to the drive wheels increases the torque input to an operating member such as an auxiliary machine immediately before execution of the fuel cut control. As a result, even if the output torque of the internal combustion engine decreases with the execution of the fuel cut control, the variation width of the torque in the drive wheels and the power system becomes smaller. Further, the torque directed from the internal combustion engine to the drive wheels is relatively increased immediately after the execution of the fuel cut control by reducing the torque input to the operating members such as the auxiliary equipment. As a result, the fuel cut control is performed. Even if the output torque of the internal combustion engine decreases with the execution, the variation width of the torque in the drive wheels and the power system becomes small.
For this reason, it is possible to suppress or prevent shock and vibration caused by executing the fuel cut control.

According to the eighth aspect of the present invention,
Even when the internal combustion engine and the drive wheels are more firmly connected, the fuel cut control is executed and the output torque of the internal combustion engine changes, so that the torque directed to the drive wheels in the power system is changed. Since the range of change is suppressed, shocks and vibrations can be suppressed or prevented even if torque fluctuations occur due to execution of the fuel cut control.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a control example according to the present invention.

FIG. 2 is a time chart schematically showing a change in output torque when the control of FIG. 1 is performed.

FIG. 3 is a flowchart showing another control example of the present invention.

FIG. 4 is a flowchart showing still another control example of the present invention.

FIG. 5 is a time chart schematically showing a change in output torque when the control shown in FIG. 4 is performed.

FIG. 6 is a flowchart showing another control example of the present invention.

FIG. 7 is a flowchart showing still another control example of the present invention.

FIG. 8 is a diagram schematically showing an example of a power system of a vehicle equipped with an internal combustion engine as an object of the present invention.

FIG. 9 is a diagram schematically showing a connection relationship between a supply / exhaust system and an auxiliary machine for the internal combustion engine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1: Internal combustion engine, 2: Transmission, 3: Lock-up clutch, 4: Torque converter, 5: Continuously variable transmission mechanism,
7 ... drive wheel, 8 ... cylinder, 9 ... piston, 1
0: intake port, 12: intake valve, 16: electronic throttle valve, 18: ISC valve, 21, 22, electronic control unit, 23: compressor for air conditioner.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02D 9/02 315 F02D 9/02 315C 11/10 11/10 F 13/02 13/02 DH 43 / 00 301 43/00 301K 301L 301Z 301H F term (reference) 3G065 AA11 CA00 DA04 GA09 GA10 GA11 GA31 GA46 HA22 JA04 JA09 JA11 KA02 3G084 BA05 BA06 BA13 BA23 BA34 DA02 DA11 DA39 FA10 3G092 AA01 AA11 BA03 EA10 DC03 DC04 FA04 FA14 FA24 GA13 HE01Z HE08Z HF04Z HF08Z HF11Z HF21Z 3G301 HA01 HA19 JA02 JA04 JA37 KA10 KA16 KA26 LA03 LA04 MA24 PE01Z PE08Z PF01Z PF03Z PF07Z PF13Z

Claims (8)

[Claims] In a control apparatus for an internal combustion engine that performs fuel cut control for stopping supply of fuel to the internal combustion engine during traveling, when it is determined that the fuel cut control is to be executed, the internal combustion engine immediately before the fuel cut control is executed. Immediately before fuel cut control means for controlling the torque from the internal combustion engine to the drive wheels in the power system from the engine to the drive wheels in a decreasing direction, and when the fuel cut control is executed, immediately after the execution of the fuel cut control, An internal combustion engine comprising at least one of a fuel cut immediately after control means for controlling a torque from the internal combustion engine to the drive wheels in an increasing direction in a power system from the engine to the drive wheels. Control device. 2. The fuel cut immediately before control means,
2. The control of an internal combustion engine according to claim 1, wherein the control means is a means for reducing an intake air amount to the internal combustion engine, and the control means immediately after fuel cut is a means to increase an intake air amount to the internal combustion engine. apparatus. 3. The internal combustion engine includes an electrically controllable throttle valve, wherein the control means immediately before fuel cut is means for reducing an opening degree of the throttle valve, and the control means immediately after fuel cut includes: 3. The control device for an internal combustion engine according to claim 1, wherein the control device is means for increasing an opening degree of the throttle valve. 4. The engine according to claim 1, further comprising a throttle valve whose opening is changed by an acceleration / deceleration operation, and another valve for controlling an amount of air sucked by bypassing the throttle valve. 3. The control device according to claim 1, wherein the control unit is a unit that reduces an opening degree of the other valve, and the control unit immediately after the fuel cut is a unit that increases an opening degree of the other valve. 4. A control device for an internal combustion engine according to claim 1. 5. The control means immediately before fuel cut, wherein the internal combustion engine is a reciprocating internal combustion engine in which a piston reciprocates in a cylinder, and includes an intake valve that opens and closes an intake port of the cylinder in conjunction with the piston. 2. The control of the internal combustion engine according to claim 1, wherein the control unit and the control unit immediately after the fuel cut change the closing timing of the intake valve in a direction in which the amount of intake air in the cylinder decreases. 3. apparatus. 6. An operating member for receiving torque from the power system, wherein the control unit immediately before fuel cut reduces the torque of the power system by increasing a torque input to the operating member, 2. The control device for an internal combustion engine according to claim 1, wherein the control unit immediately after the fuel cut is a unit that relatively increases the torque of the power system by reducing the torque input to the operating member. 3. . 7. The operating member is an auxiliary machine connected to the internal combustion engine, the control unit immediately before fuel cut is a unit for increasing a driving torque of the auxiliary machine, and the control unit immediately after fuel cut is an auxiliary unit. 7. The control device for an internal combustion engine according to claim 6, wherein the control device is means for reducing a driving torque of the auxiliary device. 8. The power system includes a variable torque transmission mechanism for changing a torque transmission efficiency between the internal combustion engine and the drive wheels, and the variable torque transmission mechanism before and after execution of the fuel cut control. 8. The control device for an internal combustion engine according to claim 1, further comprising torque transmission variable control means for setting the torque transmission efficiency to be relatively high.