JP2007162506A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of inhibiting deterioration of drivability at a time of recovery from fuel cut by appropriately securing negative pressure in an intake system while preventing introduction of fresh air to a catalyst at a time of fuel cut. <P>SOLUTION: The control device for the internal combustion engine controls the internal combustion engine executing fuel cut during deceleration of a vehicle. An intake valve control means closes an intake valve provided at a combustion chamber during fuel cut. An intake system sealing valve control means controls an intake system sealing valve provided in the intake air passage to close at a time of start of fuel cut. Consequently, flow-in of intake air to the intake air passage between the intake valve and the intake system sealing valve is shut off and a negative pressure condition is maintained during fuel cut. Sudden torque rise at a time of recovery from fuel cut can be inhibited while performing quick introduction of fresh air to a catalyst by the control device for the internal combustion engine. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine that performs control for the purpose of suppressing deterioration of a catalyst due to fuel cut.

  Conventionally, when a fuel stop (fuel cut) is executed at the time of deceleration of a vehicle, control for preventing introduction of fresh air into the exhaust system has been performed. Such control is performed to suppress deterioration of the catalyst.

  For example, Patent Document 1 discloses that at the time of fuel cut, at least one of an intake valve and an exhaust valve is stopped in a closed state to prevent introduction of fresh air into the exhaust system, and the brake booster negative pressure is a predetermined value or less. In this case, a technique is described in which the negative pressure of the brake booster is secured by releasing the suspension of the intake and exhaust valves for one or more cylinders.

JP 2004-143990 A

  However, in the technique described in Patent Document 1 described above, a large amount of intake air may flow into the combustion chamber due to insufficient negative pressure in the intake system when the fuel cut is restored. there were. Therefore, when the fuel cut is restored, a sudden torque increase may occur, and drivability may deteriorate.

  The present invention has been made to solve such problems, and its purpose is to appropriately secure a negative pressure in the intake system while preventing the introduction of fresh air into the catalyst at the time of fuel cut. Thus, an object of the present invention is to provide a control device for an internal combustion engine that can suppress deterioration in drivability when returning from a fuel cut.

  In one aspect of the present invention, an internal combustion engine control device includes: an intake valve control unit that controls an intake valve provided in a combustion chamber to be closed at the start of a fuel cut executed when a vehicle is decelerated; and the fuel cut And an intake system sealing valve control means for controlling the intake system sealing valve provided in the intake passage to be closed at the start of the operation.

  The control device for an internal combustion engine is a device that controls an internal combustion engine in which fuel cut is performed when the vehicle is decelerated. The intake valve control means controls the intake valve provided in the combustion chamber to be closed at the time of fuel cut. Thereby, fresh air introduction to the catalyst provided in the exhaust passage is blocked. On the other hand, the intake system sealing valve control means controls the intake system sealing valve provided in the intake passage to be closed at the start of fuel cut. Thereby, the inflow of intake air to the intake passage between the intake valve and the intake system sealing valve is blocked at the time of fuel cut. Therefore, the pressure in the intake passage between the intake valve and the intake system sealing valve during the fuel cut is maintained in a negative pressure state before the fuel cut is executed. Therefore, when the fuel cut is restored (that is, when the fuel cut is stopped and intake air is supplied to the engine), a large amount of intake air flows into the combustion chamber when the intake valve and the intake system sealing valve are opened. Can be suppressed. As described above, according to the control device for an internal combustion engine described above, it is possible to quickly shut off the introduction of fresh air to the catalyst at the time of fuel cut, and to suppress a sudden increase in torque when the fuel cut is restored. As a result, it is possible to prevent drivability from deteriorating.

  In one aspect of the control apparatus for an internal combustion engine, the intake system sealing valve may be a valve provided downstream of the throttle valve. As a result, a negative pressure can be reliably ensured in the intake passage between the intake valve and the intake system sealing valve.

  In another aspect of the control device for an internal combustion engine, the intake system sealing valve may be a throttle valve configured to have a high degree of sealing when fully closed. Thereby, it becomes possible to ensure a negative pressure at the time of fuel cut using an existing configuration without newly providing a valve or the like.

  In another aspect of the present invention, a control device for an internal combustion engine includes fresh air introduction blocking means for blocking fresh air introduction to a catalyst provided on an exhaust passage at the start of a fuel cut executed when the vehicle is decelerated. And a negative pressure securing means for securing a negative pressure in the intake system when the fuel cut is restored.

  The control apparatus for an internal combustion engine shuts off the introduction of fresh air to the catalyst at the start of the fuel cut by the fresh air introduction and shutting means, and reduces the negative pressure of the intake system when the fuel cut is restored by the negative pressure securing means. Secure. Specifically, the negative pressure securing means performs control so that the intake system is maintained in a negative pressure state when the fuel cut is restored. As a result, it is possible to quickly prevent the introduction of fresh air to the catalyst at the time of the fuel cut and to suppress a sudden increase in torque when the fuel cut is restored.

  In one aspect of the control apparatus for an internal combustion engine, the negative pressure securing means secures the negative pressure of the intake system by sucking the intake air in the intake passage using a pump during the fuel cut.

  In this aspect, the negative pressure securing means maintains the intake system in a negative pressure state by sucking air in the intake passage using a pump. That is, a negative pressure state in the intake passage is created using a pump.

  In another aspect of the control apparatus for an internal combustion engine, the negative pressure securing means supplies the negative pressure accumulated in the tank to the intake passage immediately before the fuel cut is restored, thereby Ensure negative pressure in the intake system.

  In this aspect, the negative pressure securing means secures the negative pressure of the intake system when returning from the fuel cut, using the negative pressure accumulated in the tank. That is, the negative pressure state of the intake system is created by supplying negative pressure from the negative pressure tank.

  Preferably, the fresh air introduction blocking means is one of an intake valve provided in the combustion chamber, an exhaust valve provided in the combustion chamber, and an exhaust throttle valve provided in an exhaust passage upstream of the catalyst. Is closed.

  Preferred embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment]
First, a first embodiment of the present invention will be described.

(overall structure)
FIG. 1 is a schematic configuration diagram of an engine to which the control device for an internal combustion engine according to the first embodiment is applied.

  An intake passage 3 is connected to the engine 6, and intake air that has passed through the intake passage 3 is supplied and fuel is supplied from the fuel injection valve 2. The engine 6 generates power to be applied to the vehicle by causing the intake air and fuel to explode in the combustion chamber 6a. In this case, the reciprocating motion of the piston 6b is transmitted to the crankshaft (not shown) via the connecting rod 6c, and power is transmitted by rotating the crankshaft. An exhaust passage 9 is connected to the engine 6, and exhaust gas generated by combustion is discharged from the exhaust passage 9.

  Further, an intake valve 7 and an exhaust valve 8 are provided in the combustion chamber 6 a of the engine 6. The intake valve 7 controls conduction / interruption between the intake passage 3 and the combustion chamber 6a by opening and closing. Specifically, the intake valve 7 is connected to an actuator 12 and is configured to be electrically driven. That is, the opening degree of the intake valve 7 is controlled by the actuator 12. Further, the exhaust valve 8 controls opening / closing of the exhaust passage 9 and the combustion chamber 6a by opening and closing.

  In the intake passage 3, a throttle valve 4, an intake system sealing valve 11, and an intake manifold 5 are provided in order from the upstream side. The throttle valve 4 is a valve that adjusts the amount of intake air flowing through the intake passage 3. The intake system sealing valve 11 is a valve that is provided on the intake passage 3 between the throttle valve 4 and the intake manifold 5, and switches between intake air flow and cutoff in the intake passage 3. The intake manifold (surge tank) 5 is a tank that temporarily stores intake air supplied to the engine 6. The exhaust passage 9 is provided with a catalyst (not shown) for purifying the exhaust gas.

  The ECU (Engine Control Unit) 50 includes a CPU, a ROM, a RAM, an A / D converter, an input / output interface, and the like (not shown). The ECU 50 mainly supplies the control signal S2 to the fuel injection valve 2 to control the fuel injection amount, and controls the opening of the intake valve 7 by supplying the control signal S12 to the actuator 12. By supplying a control signal S12 to the intake system sealing valve 11, the opening and closing of the intake system sealing valve 11 is controlled. Accordingly, the ECU 50 functions as a control device for the internal combustion engine in the present invention, and operates as an intake valve control means and an intake system sealing valve control means. Specifically, the ECU 50 controls the fuel injection valve 2 so that fuel injection is stopped when the vehicle is decelerated, thereby executing fuel cut (hereinafter also referred to as “F / C”). Further, when starting the fuel cut, the ECU 50 controls the intake valve 7 to be closed and controls the intake system seal valve 11 to be closed.

  As described above, the intake valve 7 is closed when the fuel cut is started in order to prevent introduction of fresh air into the catalyst provided in the exhaust passage 9. That is, it is for suppressing deterioration of the catalyst at the time of fuel cut.

  In addition, when the fuel cut is started, the intake system sealing valve 11 is closed because the intake air flows into the intake passage 3 (including the intake manifold 5) between the intake valve 7 and the intake system sealing valve 11. This is to shut off. In other words, the pressure in the intake passage 3 (hereinafter referred to as “negative pressure accumulating passage 15”) between the intake valve 7 and the intake system sealing valve 11 during the fuel cut is set to the negative pressure before the fuel cut is executed. This is to maintain the state. Thus, when the fuel cut is restored (that is, when the fuel cut is stopped and intake air is supplied to the engine 6), when the intake valve 7 and the intake system sealing valve 11 are opened, a large amount of fuel is discharged from the combustion chamber. It is possible to suppress the intake air from flowing in. Therefore, it is possible to suppress a sudden increase in torque when the fuel cut is restored.

  In the following, control performed at the start of fuel cut (control at fuel cut start) and control performed at the time of return of fuel cut (control at fuel cut return) will be described.

(Control at start of fuel cut)
FIG. 2 is a diagram illustrating a flowchart of fuel cut start control according to the first embodiment. This control is executed by the ECU 50.

  First, in step S101, the ECU 50 determines whether or not there is a fuel cut request. This request is issued when the vehicle decelerates, for example. If there is a request for fuel cut (step S101; Yes), the process proceeds to step S102. If there is no request for fuel cut (step S101; No), the process exits the flow.

  In step S102, the ECU 50 supplies the control signal S11 to the intake system sealing valve 11, thereby setting the intake system sealing valve 11 to be closed. Then, the process proceeds to step S103. In step S103, the ECU 50 sets the intake valve 7 to be closed (pauses) by supplying a control signal S12 to the actuator 12 of the intake valve 7. As a result, the introduction of fresh air into the catalyst is prevented, and a negative pressure is secured in the negative pressure accumulating passage 15 between the intake system sealing valve 11 and the intake valve 7. Then, the process proceeds to step S104.

  In step S104, the ECU 50 performs fuel cut by supplying a control signal S2 to the fuel injection valve 2 so that fuel injection is stopped. Then, the process exits the flow.

(Control when returning from fuel cut)
FIG. 3 is a diagram illustrating a flowchart of the fuel cut return control according to the first embodiment. This control is executed by the ECU 50.

  First, in step S201, the ECU 50 determines whether or not there is a fuel cut return request. This request is issued, for example, when the vehicle accelerates. If there is a fuel cut return request (step S201; Yes), the process proceeds to step S202. If there is no fuel cut return request (step S201; No), the process exits the flow.

  In step S202, the ECU 50 supplies the control signal S11 to the intake system sealing valve 11, thereby setting the intake system sealing valve 11 to open. Then, the process proceeds to step S203. In step S203, the ECU 50 supplies the control signal S12 to the actuator 12 of the intake valve 7 to set (activate) the intake valve 7 to open. As a result, intake air is supplied to the engine 6. In this case, since the negative pressure secured in the negative pressure accumulation passage 15 is supplied to the engine 6, a large amount of intake air is not supplied to the engine 6. When the process of step S203 ends, the process proceeds to step S204.

  In step S204, the ECU 50 stops fuel cut and executes fuel injection. In this case, since a large amount of intake air is not supplied to the engine 6, a sharp increase in torque does not occur when fuel injection is executed. When the above process ends, the process exits the flow.

  As described above, according to the control apparatus for an internal combustion engine according to the first embodiment, it is possible to appropriately ensure the negative pressure of the intake system while quickly shutting off the introduction of fresh air to the catalyst at the time of fuel cut. it can. As a result, it is possible to suppress an abrupt increase in torque after returning from the fuel cut and to suppress deterioration in drivability. Further, by using the ensured negative pressure secured in the negative pressure accumulating passage 15, it becomes possible to appropriately operate the brake booster, the actuator using the negative pressure, and the like at the time of fuel cut.

  In the above, an example in which the intake system seal valve 11 is provided and a negative pressure is secured in the negative pressure accumulation passage 15 between the intake system seal valve 11 and the intake valve 7 has been shown, but the intake system seal valve 11 is provided. Instead, it is also possible to secure a negative pressure using a throttle valve. That is, when the fuel cut is started, the throttle valve is set to be fully closed, and a negative pressure can be secured in the intake passage 3 between the throttle valve and the intake valve 7. In this case, it is preferable to use a throttle valve configured to have a high degree of sealing when fully closed. This is to suppress negative pressure leakage from the throttle valve. Thus, when a valve configured to have a high degree of sealing when fully closed is employed as the throttle valve, the throttle valve functions as an intake system sealing valve according to the present invention.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the second embodiment, instead of securing a negative pressure in the negative pressure accumulating passage 15, the air in the intake passage 3 is sucked by using a pump (hereinafter referred to as “negative pressure producing pump”), thereby It differs from the first embodiment in that the system is maintained in a negative pressure state. That is, in the first embodiment, the negative pressure state before the fuel cut is maintained using the negative pressure accumulating passage 15, but in the second embodiment, the negative pressure state is prepared using a negative pressure production pump.

  FIG. 4 is a schematic configuration diagram of an engine to which the control device for an internal combustion engine according to the second embodiment is applied. The configuration according to the first embodiment shown in FIG. 1 is different from the configuration according to the first embodiment in that a negative pressure production pump 21 and a pump conduction passage 22 are provided without the intake system sealing valve 11. In the second embodiment, the ECU 51 performs control instead of the ECU 50. In addition, the same code | symbol is attached | subjected to the component same as the component shown in FIG. 1, and the description is abbreviate | omitted.

  The pump conduction passage 22 is a passage through which the intake manifold 5 and the negative pressure production pump 21 are conducted. The negative pressure production pump 21 sucks the intake air in the intake manifold 5 through the pump conduction passage 22 at the start of fuel cut (see arrow 100). And the negative pressure production pump 21 stops the suction | inhalation of intake air at the time of a fuel cut return.

  The ECU 51 mainly supplies the control signal S2 to the fuel injection valve 2 to control the fuel injection amount, and supplies the control signal S12 to the actuator 12 of the intake valve 7, thereby opening the intake valve 7. And the operation of the negative pressure production pump 21 is controlled by supplying a control signal S21 to the negative pressure production pump 21. Thus, the ECU 51 functions as a fresh air introduction / blocking unit that blocks the introduction of fresh air into the catalyst and a negative pressure securing unit that secures the negative pressure of the intake system.

  Specifically, the ECU 51 controls the intake valve 7 to be closed so that the introduction of fresh air into the catalyst is interrupted at the start of fuel cut. Further, the ECU 51 performs suction of the intake air by the negative pressure producing pump 21 at the start of the fuel cut so that the negative pressure of the intake system at the time of the fuel cut return is secured. By controlling the negative pressure production pump 21 in this way, the intake passage 3 from the intake manifold 5 to the intake valve 7 is maintained in a negative pressure state.

  Next, fuel cut start control and fuel cut return control according to the second embodiment will be described with reference to FIGS. 5 and 6.

  FIG. 5 is a diagram illustrating a flowchart of fuel cut start control according to the second embodiment. This control is executed by the ECU 51.

  First, in step S301, the ECU 51 determines whether or not there is a fuel cut request. If there is a request for fuel cut (step S301; Yes), the process proceeds to step S302. If there is no request for fuel cut (step S301; No), the process exits the flow.

  In step S <b> 302, the ECU 51 starts the operation of the negative pressure production pump 21 by supplying a control signal S <b> 21 to the negative pressure production pump 21. That is, the suction of the intake air by the negative pressure production pump 21 is started. Then, the process proceeds to step S303. In step S303, the ECU 51 supplies the control signal S12 to the actuator 12 of the intake valve 7 to set the intake valve 7 to be closed (pause). As a result, the introduction of fresh air to the catalyst is prevented and the intake system is maintained in a negative pressure state. Then, the process proceeds to step S304.

  In step S304, the ECU 51 executes fuel cut by supplying a control signal S2 so that fuel injection from the fuel injection valve 2 is stopped. Then, the process exits the flow.

  FIG. 6 is a diagram illustrating a flowchart of the fuel cut return control according to the second embodiment. This control is executed by the ECU 51.

  First, in step S401, the ECU 51 determines whether or not there is a fuel cut return request. If there is a fuel cut return request (step S401; Yes), the process proceeds to step S402. If there is no fuel cut return request (step S401; No), the process exits the flow.

  In step S <b> 402, the ECU 51 stops the operation of the negative pressure production pump 21 by supplying the control signal S <b> 21 to the negative pressure production pump 21. That is, the suction of the intake air by the negative pressure production pump 21 is stopped. Then, the process proceeds to step S403. In step S <b> 403, the ECU 51 supplies the control signal S <b> 12 to the actuator 12 of the intake valve 7 to set (activate) the intake valve 7. As a result, intake air is supplied to the engine 6. In this case, since the intake system is maintained in a negative pressure state by the negative pressure production pump 21, a large amount of intake air is not supplied to the engine 6. When the process of step S403 ends, the process proceeds to step S404.

  In step S404, the ECU 51 stops fuel cut and executes fuel injection. In this case, since a large amount of intake air is not supplied to the engine 6, a sharp increase in torque does not occur when fuel injection is executed. When the above process ends, the process exits the flow.

  As described above, the internal combustion engine control apparatus according to the second embodiment can also appropriately ensure the negative pressure of the intake system while quickly shutting off the introduction of fresh air to the catalyst at the time of fuel cut. . As a result, it is possible to suppress an abrupt increase in torque after returning from the fuel cut and to suppress deterioration in drivability. Further, by using the negative pressure produced by the negative pressure production pump 21, it is possible to appropriately operate a brake booster, an actuator that uses negative pressure, and the like at the time of fuel cut.

  In addition, this invention is not limited to performing control for ensuring a negative pressure using the negative pressure production pump 21. FIG. In another example, a negative pressure in the intake system can be secured by using a brake booster pump instead of the negative pressure production pump 21.

[Third Embodiment]
Next, a third embodiment of the present invention will be described.

  Unlike the second embodiment, the third embodiment uses the negative pressure accumulated in a tank (hereinafter referred to as “negative pressure tank”) to ensure the negative pressure of the intake system when the fuel cut is restored. That is, in the third embodiment, the negative pressure state of the intake system is created by supplying negative pressure from the negative pressure tank at the time of fuel cut return (specifically, immediately before the return of fuel cut).

  FIG. 7 is a schematic configuration diagram of an engine to which the control device for an internal combustion engine according to the third embodiment is applied. The configuration according to the second embodiment shown in FIG. 4 is that the negative pressure production pump 21 and the pump conduction passage 22 are not provided, but the negative pressure tank 31, the negative pressure supply valve 32, and the negative pressure supply passage 33 are provided. Different. In the third embodiment, the ECU 52 performs control instead of the ECU 51. Note that the same components as those illustrated in FIG. 4 are denoted by the same reference numerals, and the description thereof is omitted.

  The negative pressure tank 31 stores a negative pressure therein and is connected to the intake manifold 5 via a negative pressure supply passage 33. Further, a negative pressure supply valve 32 is provided on the negative pressure supply passage 33. When the negative pressure supply valve 32 is open, the negative pressure in the negative pressure tank 31 is supplied to the intake manifold 5. On the other hand, when the negative pressure supply valve 32 is closed, the negative pressure in the negative pressure tank 31 is not supplied to the intake manifold 5.

  The ECU 52 mainly supplies the control signal S2 to the fuel injection valve 2 to control the fuel injection amount, and supplies the control signal S12 to the actuator 12 of the intake valve 7, thereby opening the intake valve 7. The negative pressure supply in the negative pressure tank 31 is controlled by supplying the control signal S32 to the negative pressure supply valve 32. Thus, the ECU 52 functions as a fresh air introduction / blocking means for blocking the introduction of fresh air into the catalyst and a negative pressure securing means for securing the negative pressure of the intake system.

  Specifically, the ECU 52 performs the fuel cut by controlling the fuel injection valve 2 so that the fuel injection is stopped when the vehicle is decelerated, and the intake valve so as to block the introduction of fresh air to the catalyst. 7 is closed. Further, the ECU 52 supplies negative pressure to the intake passage 3 by opening the negative pressure supply valve 32 immediately before the fuel cut is restored. By opening the negative pressure supply valve 32 in this way, the intake passage 3 is maintained in a negative pressure state when the fuel cut is restored.

  Next, fuel cut start control and fuel cut return control according to the third embodiment will be described with reference to FIGS. 8 and 9.

  FIG. 8 is a view illustrating a flowchart of the fuel cut start control according to the third embodiment. This control is executed by the ECU 52.

  First, in step S501, the ECU 52 determines whether or not there is a fuel cut request. If there is a fuel cut request (step S501; Yes), the process proceeds to step S502. If there is no fuel cut request (step S501; No), the process exits the flow.

  In step S502, the ECU 52 sets the negative pressure supply valve 32 to be closed by supplying a control signal S32 to the negative pressure supply valve 32. If the negative pressure supply valve 32 is kept open as it is, the negative pressure in the negative pressure tank 31 will be released (in other words, the pressure in the intake passage 3 will increase, so the internal pressure in the negative pressure tank 31 will increase). Therefore, the negative pressure supply valve 32 is set to be closed, and the negative pressure tank 31 is maintained in a negative pressure state. Then, the process proceeds to step S503. In step S503, the ECU 52 sets the intake valve 7 to be closed (pauses) by supplying the control signal S12 to the actuator 12 of the intake valve 7. Thus, the introduction of fresh air to the catalyst is prevented and the negative pressure tank 31 is maintained in a negative pressure state. Then, the process proceeds to step S504.

  In step S504, the ECU 52 performs fuel cut by supplying a control signal S2 so that fuel injection from the fuel injection valve 2 is stopped. Then, the process exits the flow.

  FIG. 9 is a view illustrating a flowchart of fuel cut return control according to the third embodiment. This control is executed by the ECU 52.

  First, in step S601, the ECU 52 determines whether or not there is a fuel cut return request. If there is a fuel cut return request (step S601; Yes), the process proceeds to step S602. If there is no fuel cut return request (step S601; No), the process exits the flow.

  In step S602, the ECU 52 sets the negative pressure supply valve 32 to open by supplying a control signal S32 to the negative pressure supply valve 32. That is, supply of negative pressure from the negative pressure tank 31 is started. Then, the process proceeds to step S603. In step S603, the ECU 52 sets the intake valve 7 to open (actuates) by supplying a control signal S12 to the actuator 12 of the intake valve 7. As a result, intake air is supplied to the engine 6. In this case, since the negative pressure in the negative pressure tank 31 is supplied to the intake passage 3 and the intake system is maintained in a negative pressure state, a large amount of intake air is not supplied to the engine 6. When the process of step S603 ends, the process proceeds to step S604.

  In step S604, the ECU 52 stops the fuel cut and executes fuel injection. In this case, since a large amount of intake air is not supplied to the engine 6, a sharp increase in torque does not occur when fuel injection is executed. When the above process ends, the process exits the flow.

  As described above, the internal combustion engine control apparatus according to the third embodiment can also appropriately ensure the negative pressure of the intake system while quickly shutting off the introduction of fresh air to the catalyst at the time of fuel cut. . As a result, it is possible to suppress an abrupt increase in torque after returning from the fuel cut and to suppress deterioration in drivability. Further, by using the negative pressure supplied from the negative pressure tank 31, it is possible to appropriately operate the brake booster, the actuator using the negative pressure, and the like.

  The present invention is not limited to securing the negative pressure by separately providing the negative pressure tank 31 and the negative pressure supply valve 32 and controlling the negative pressure supply valve 32 as described above. In another example, instead of the negative pressure tank 31, a tank used to drive various actuators (a tank in which negative pressure is accumulated) is used to secure the negative pressure of the intake system when the fuel cut is restored. Is also possible.

[Modification]
In the second embodiment and the third embodiment described above, an example in which the intake valve 7 is set to be closed and the introduction of fresh air is blocked has been shown, but instead of the intake valve 7 being set to be closed, the exhaust valve 8 is set. It is also possible to block the introduction of fresh air by closing. In this case, the exhaust valve 8 is preferably controlled using an actuator that can electrically control the opening and closing of the valve.

  In still another example, instead of using the intake valve 7 and the exhaust valve 8 to block the introduction of fresh air, an exhaust throttle valve is provided on the exhaust passage 9 on the upstream side of the catalyst. It is also possible to block the introduction. Thus, the ECUs 51 and 52 function as the fresh air introduction / blocking means in the present invention by controlling any one of the intake valve 7, the exhaust valve 8, and the exhaust throttle valve.

1 is a schematic configuration diagram of an engine to which a control device for an internal combustion engine according to a first embodiment of the present invention is applied. It is a flowchart of the fuel cut start time control which concerns on 1st Embodiment. It is a flowchart of the fuel cut return time control according to the first embodiment. It is a schematic block diagram of the engine to which the control apparatus of the internal combustion engine which concerns on 2nd Embodiment of this invention was applied. It is a flowchart of the fuel cut start time control which concerns on 2nd Embodiment. It is a flowchart of the fuel cut return time control according to the second embodiment. It is a schematic block diagram of the engine to which the control apparatus of the internal combustion engine which concerns on 3rd Embodiment of this invention was applied. It is a flowchart of the fuel cut start time control which concerns on 3rd Embodiment. It is a flowchart of the fuel cut return control which concerns on 3rd Embodiment.

Explanation of symbols

2 Fuel Injection Valve 3 Intake Passage 4 Throttle Valve 5 Intake Manifold 6 Engine 7 Intake Valve 8 Exhaust Valve 9 Exhaust Passage 11 Intake System Sealing Valve 21 Negative Pressure Preparation Pump 31 Negative Pressure Tank 32 Negative Pressure Supply Valve 50, 51, 52 ECU

Claims (9)

An intake valve control means for controlling the intake valve provided in the combustion chamber to be closed at the start of fuel cut executed when the vehicle is decelerated;
An internal combustion engine control device comprising: an intake system sealing valve control means for controlling an intake system sealing valve provided in an intake passage to be closed at the start of the fuel cut.   The control apparatus for an internal combustion engine according to claim 1, wherein the intake system sealing valve is a valve provided downstream of the throttle valve.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the intake system sealing valve is a throttle valve configured to have a high sealing degree when fully closed. A fresh air introduction shut-off means for shutting off the fresh air introduction to the catalyst provided on the exhaust passage at the start of fuel cut executed when the vehicle decelerates;
A control apparatus for an internal combustion engine, comprising: negative pressure securing means for securing a negative pressure in the intake system when the fuel cut is restored.   5. The internal combustion engine according to claim 4, wherein the negative pressure securing means secures a negative pressure of the intake system by sucking intake air in an intake passage using a pump during the fuel cut. Control device.   The negative pressure securing means secures the negative pressure of the intake system by supplying the negative pressure accumulated in the tank to the intake passage immediately before the return of the fuel cut. Item 5. The control device for an internal combustion engine according to Item 4.   The control apparatus for an internal combustion engine according to any one of claims 4 to 6, wherein the fresh air introduction blocking means controls an intake valve provided in the combustion chamber to be closed.   The control apparatus for an internal combustion engine according to any one of claims 4 to 6, wherein the fresh air introduction blocking means controls an exhaust valve provided in the combustion chamber to be closed.   The internal combustion engine according to any one of claims 4 to 6, wherein the fresh air introduction blocking means controls an exhaust throttle valve disposed in an exhaust passage upstream of the catalyst to be closed. Control device.

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