JP2007009779A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To limit oil consumption quantity while inhibiting deterioration of catalyst and secure deceleration feeling at a time of deceleration fuel cut in relation to a control device for an internal combustion engine. <P>SOLUTION: When a fuel cut condition is established at a time of deceleration, a suction air quantity adjusting means is operated to a side reducing suction air quantity and fuel cut of a plurality of cylinders is executed by operating a fuel cut means. Also, a recirculation quantity adjusting means is operated to a side increasing exhaust gas recirculation quantity and at least one of cylinders of the plurality of the cylinders are deactivated by operating a cylinder deactivation means. And then, cylinder deactivation by the cylinder deactivation means is removed when exhaust gas recirculation quantity is increased to a desired quantity. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine having a plurality of cylinders, and more particularly to a control device for an internal combustion engine that performs fuel cut during deceleration.

  Conventionally, for example, in Patent Document 1, the operating states of the intake valve and the exhaust valve at the time of cylinder deactivation are controlled so as to achieve both suppression of catalyst deterioration during deceleration of the internal combustion engine and securing of a feeling of deceleration by engine braking. Technology is disclosed.

  In an internal combustion engine, when deceleration is requested by a driver, a fuel cut (hereinafter referred to as a deceleration fuel cut) is generally executed to improve fuel consumption characteristics. For this reason, when the internal combustion engine is decelerated, there occurs a situation in which lean air containing no fuel flows from the intake passage to the exhaust passage.

  A catalyst disposed in an exhaust passage of an internal combustion engine has a characteristic that it is easily deteriorated by receiving a lean gas supply in a high temperature environment. For this reason, in order to suppress the deterioration of the catalyst during the fuel cut, it is desired to reduce the amount of air flowing when the internal combustion engine is decelerated. Thus, when the internal combustion engine is decelerated, the amount of circulating air is reduced by controlling the throttle to the closed side (for example, by setting the opening to an idle position).

However, when the throttle is closed, the pressure inside the intake pipe is greatly reduced. When a large negative pressure is generated in the intake pipe, the in-cylinder pressure of the internal combustion engine is easily reduced to a negative pressure. When the in-cylinder pressure is reduced to a negative pressure, oil consumption in the internal combustion engine increases due to so-called oil rise. For this reason, from the viewpoint of suppressing oil consumption, it is desirable that the intake pipe pressure during deceleration of the internal combustion engine is not excessively negative.

  As a means for suppressing an increase in the intake pipe negative pressure, a cylinder deactivation technique is known in which at least one of an intake valve and an exhaust valve is closed in some of a plurality of cylinders to deactivate the cylinder. According to cylinder deactivation, the air density in the surge tank increases by the number of deactivated cylinders, so that excessive negative pressure of the intake pipe pressure can be suppressed.

  However, when the cylinder is deactivated, the air flow is lost in the deactivated cylinder, and the friction decreases. As a result, there is a possibility that a feeling of deceleration cannot be obtained due to insufficient engine braking.

The above-described conventional system controls the operation state of the intake valve and the exhaust valve when the cylinder is deactivated. Specifically, the operation is performed by operating either the intake valve or the exhaust valve without deactivation. Opening and closing of the valve to be caused causes a pumping loss to generate an engine braking effect.
JP 2004-143990 A JP 2001-182570 A JP 2004-137969 A

  According to the above conventional system, when the internal combustion engine is decelerated, the air density in the surge tank is increased by stopping some cylinders, and excessive negative pressure of the intake pipe pressure is suppressed. However, the conventional system described above suppresses the deterioration of the catalyst when the internal combustion engine decelerates, secures the feeling of deceleration by engine braking, and suppresses the oil consumption. It is to be achieved only by control, that is, only by control of a single actuator. In this respect, the conventional system described above still leaves room for improvement in any aspect of suppressing deterioration of the catalyst, ensuring a feeling of deceleration, and suppressing oil consumption.

  The present invention has been made in order to solve the above-described problems, and at the time of deceleration fuel cut, an internal combustion engine that suppresses deterioration of the catalyst while suppressing oil consumption and securing a feeling of deceleration. An object of the present invention is to provide an engine control device.

In order to achieve the above object, a first invention is a control device for an internal combustion engine having a plurality of cylinders,
Fuel cut means for performing fuel cut on the plurality of cylinders;
An intake air amount adjusting means for adjusting the intake air amount;
A recirculation amount adjusting means for adjusting a recirculation amount of exhaust gas;
Cylinder deactivation means for deactivating the cylinder by closing at least one of the intake valve and the exhaust valve for at least one of the plurality of cylinders;
Fuel cut determination means for determining whether a fuel cut condition is satisfied at the time of deceleration of the internal combustion engine;
When the fuel cut condition is satisfied, the first control for operating the intake air amount adjusting means on the side to reduce the intake air amount, and the fuel cut means for operating the fuel cut for the plurality of cylinders. A second control for controlling, a third control for operating the recirculation amount adjusting means to increase the exhaust gas recirculation amount, and at least one cylinder among the plurality of cylinders by operating the cylinder deactivation means And a fourth control for canceling the cylinder deactivation by the cylinder deactivation means when the exhaust gas recirculation amount is increased to a desired amount,
It is characterized by having.

According to a second invention, in the first invention,
The recirculation amount adjusting means is a variable valve timing mechanism that changes an overlap period of the intake valve and the exhaust valve.

According to a third invention, in the first invention,
The recirculation amount adjusting means is an EGR valve disposed in an EGR passage connecting the exhaust passage and the intake passage.

A fourth invention is any one of the first to third inventions,
A fuel cut return determination means for determining the establishment of a return condition from the fuel cut;
The control means activates the cylinder deactivation means to deactivate at least one of the plurality of cylinders when the fuel cut return condition is satisfied, and deactivates among the plurality of cylinders. Sixth control for canceling fuel cut by the fuel cut means for cylinders other than the cylinder, seventh control for operating the recirculation amount adjusting means to reduce the exhaust gas recirculation amount, and exhaust gas recirculation When the amount is reduced to a desired amount, the cylinder deactivation by the cylinder deactivation unit is canceled, and the eighth control is performed for canceling the fuel cut by the fuel cut unit for the cylinders deactivated among the plurality of cylinders. It is characterized by that.

A fifth invention is the fourth invention,
Means for determining whether the load required for the internal combustion engine upon return from fuel cut is high or low;
The control means executes the fifth to eighth controls when the required load on the internal combustion engine is low, and when the required load on the internal combustion engine is high, Ninth control for canceling fuel cut by the fuel cut means is executed for the plurality of cylinders.

  According to the first aspect of the invention, at the time of the deceleration fuel cut, the intake air amount is reduced by the operation of the intake air amount adjusting means, thereby suppressing the deterioration of the catalyst. At this time, at least one of the plurality of cylinders is stopped with at least one of the intake valve and the exhaust valve being closed, so that consumption of air by the cylinder is eliminated and the intake pressure is reduced. Accordingly, even if the intake air amount is reduced by the operation of the intake air amount adjusting means, the increase in the intake pipe negative pressure is suppressed, and the oil rising into the combustion chamber due to the increase in the negative pressure in the combustion chamber is prevented. Thereafter, when the exhaust gas recirculation amount is increased to a desired amount by the operation of the recirculation amount adjusting means, the cylinder deactivation is released, and thereafter, the increase in the intake pipe negative pressure is suppressed by the increase in the exhaust gas recirculation amount. . By releasing the cylinder deactivation, the pumping loss of the internal combustion engine increases, and higher deceleration performance can be obtained.

  Particularly, according to the second aspect of the invention, the overlap period between the intake valve and the exhaust valve is increased by the variable valve timing mechanism, and the exhaust gas blowback amount (internal EGR amount) from the exhaust passage to the intake passage is increased. As a result, an increase in the intake pipe negative pressure can be suppressed. According to the third aspect of the invention, the intake pipe negative is adjusted by adjusting the EGR valve to the open side and increasing the flow rate (external EGR amount) of the exhaust gas supplied from the exhaust passage to the intake passage through the EGR passage. An increase in pressure can be suppressed.

  According to the fourth aspect of the invention, at the time of return from the deceleration fuel cut, at least one of the plurality of cylinders is deactivated, and the exhaust gas recirculation amount is set in a state where the fuel cut is released for the cylinders other than the deactivated cylinder. Weight loss is performed. By deactivating some cylinders, the intake pipe negative pressure is greatly reduced, and the amount of fresh air taken into the combustion chamber is increased in cylinders other than the deactivated cylinders. As a result, misfire in the cylinder from which the fuel cut has been released is avoided. Then, in a state where the exhaust gas recirculation amount is sufficiently reduced, the cylinder deactivation and the fuel cut are canceled for all the cylinders, so that it is possible to completely return from the fuel cut without causing misfire.

  Furthermore, according to the fifth aspect, when a high load is required for the internal combustion engine at the time of return from the fuel cut, the fuel cut is released for all the cylinders, so that a torque corresponding to the required load is quickly output. It becomes possible to do. In this case, since the throttle is greatly opened according to the required load, a sufficient amount of fresh air is sucked into the combustion chamber, and misfire in the cylinder where the fuel cut is released is avoided.

Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 7.
FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine (hereinafter referred to as an engine) to which a control device as an embodiment of the present invention is applied. FIG. 2 is a view of the cylinder head portion of the engine shown in FIG. 1 as viewed from above. As shown in FIG. 2, the engine according to this embodiment includes four cylinders (# 1 to # 4). In the present embodiment, the present invention is applied to an in-line four-cylinder engine, but the present invention can also be applied to other types of multi-cylinder engines such as a V type.

  The engine according to this embodiment includes a cylinder block 6 in which a piston 8 is disposed, and a cylinder head 4 assembled to the cylinder block 6. A space from the upper surface of the piston 8 to the cylinder head 4 forms a combustion chamber 10 of each cylinder. A spark plug 16 is attached to the cylinder head 4 so as to protrude from the top of the combustion chamber 10 into the combustion chamber 10.

  An intake port 18 and an exhaust port 20 are formed in the cylinder head 4 so as to communicate with the combustion chamber 10. An intake manifold 32 is connected to the intake port 18. The intake manifold 32 has a surge tank 34 and distributes air from the surge tank 34 to the intake port 18 of each cylinder. An injector 40 is attached to the intake manifold 32 so as to face the intake port 18 for each cylinder.

  The surge tank 34 is connected to an air introduction pipe 30 into which air (new gas) is introduced. An air cleaner 36 is provided at the upstream end of the air introduction pipe 30, and an air flow meter 66 that outputs a signal corresponding to the intake amount of new gas is disposed downstream of the air cleaner 36. In addition, an electronically controlled throttle 38 is disposed at a connection portion between the air introduction pipe 30 and the surge tank 34. The throttle 38 is provided with a throttle sensor 64 that outputs a signal corresponding to the opening degree.

  An exhaust manifold 42 is connected to the exhaust port 20 of the cylinder head 4. Combustion gas generated when the air-fuel mixture burns in the combustion chamber 10 is discharged from the exhaust port 20 to the exhaust manifold 42. The exhaust manifold 42 is connected to an exhaust gas exhaust pipe 44 for releasing exhaust gas (combustion gas) into the atmosphere. The exhaust gas discharge pipe 44 is provided with a catalyst 46 for purifying the exhaust gas.

  An intake valve 12 for controlling a communication state between the intake port 18 and the combustion chamber 10 is provided at a connection portion between the intake port 18 and the combustion chamber 10 in the cylinder head 4. The intake valve 12 is driven by an intake cam 26a provided on the intake camshaft 26 to perform a lift motion. Further, an exhaust valve 14 for controlling the communication state between the exhaust port 20 and the combustion chamber 10 is provided at a connection portion between the exhaust port 20 and the combustion chamber 10. The exhaust valve 14 is driven by an exhaust cam 28a provided on the exhaust camshaft 28 to perform a lift motion.

  The intake camshaft 26 and the exhaust camshaft 28 are both connected to the crankshaft 24 by a belt or chain, and rotate in synchronization with the rotation of the crankshaft 24. Among these, the intake camshaft 26 is provided with a variable valve timing mechanism 50. The valve timing variable mechanism 50 can variably control the valve timing of the intake valve 12 of each cylinder by changing the phase angle of the intake camshaft 26 with respect to the crankshaft 24.

  The configuration of the valve timing variable mechanism 50 will be specifically described. The variable valve timing mechanism 50 includes a housing (not shown) that rotates in synchronization with the crankshaft 24 and a rotor (not shown) that is disposed in the housing and rotates in synchronization with the intake camshaft 26. Two oil chambers partitioned by a rotor are provided inside the housing. The variable valve timing mechanism 50 operates when hydraulic oil is supplied to one of the oil chambers and the rotation angle of the rotor with respect to the housing changes. Specifically, when hydraulic oil is supplied to one oil chamber, the variable valve timing mechanism 50 operates so as to change the phase angle of the camshaft relative to the crankshaft to the advance side, and to the other oil chamber. When the hydraulic oil is supplied, the variable valve timing mechanism 50 operates so as to change the phase angle of the camshaft with respect to the crankshaft to the retard side. However, the configuration described above is an example of a configuration that the variable valve timing mechanism 50 can adopt, and other configurations may be used as long as the valve timing can be changed.

  Each of the cylinders # 1 to # 4 includes a variable valve gear 52 that is interposed between the intake cam 26a and the intake valve 12 to control opening and closing of the intake valve 12, and an exhaust cam 28a and an exhaust valve 14. There is provided a variable valve device 54 which is interposed between the valves and controls the opening and closing of the exhaust valve 14. The variable valve operating devices 52 and 54 can operate independently for each cylinder. 3 and 4 show the structure of a variable valve operating apparatus controlled by a hydraulic circuit. FIG. 3 is a perspective view of the variable valve operating apparatus, and FIG. 4 is a side sectional view thereof. Since the intake-side variable valve operating device 52 and the exhaust-side variable valve operating device 54 have the same configuration, the intake-side variable valve operating device 52 will be described below.

  As shown in FIG. 4, a rocker arm 102 pivotally supported by the rocker shaft 100 is provided below the intake cam 26a. An arm 104 is formed on the tip side of the rocker arm 102 so as to protrude forward. The tips of the arms 104 are in contact with the upper ends of the pair of intake valves 12 and are pressed toward the side where the intake valves 12 are closed by the urging force of a valve spring (not shown). As the rocker arm 102 pivots about the rocker shaft 100, the arm 122 swings, so that the intake valve 12 is pressed by the arm 122 to perform a lift motion.

  On the upper surface of the rocker arm 102, a movable cam follower 106 that abuts the intake cam 26a is provided. The movable cam follower 106 is slidably disposed in a slide hole 120 formed along the vertical direction of the rocker arm 102. The movable cam follower 106 is constantly biased toward the intake cam 26a by the biasing force of a coil spring (not shown). The movable cam follower 106 receives pressure from the intake cam 26a while making sliding contact with the intake cam 26a.

  A cylinder hole 122 is formed below the rocker arm 102 and intersects the sliding hole 120 in which the movable cam follower 106 is inserted. In the cylinder hole 122, a lock pin 112 for selectively fastening or releasing the locker arm 102 and the movable cam follower 106 is slidably disposed.

  Next, the cam switching mechanism configured around the lock pin 112 will be described in detail with reference to FIGS. 5A and 5B. 5A and 5B are cross-sectional views showing a side cross-sectional structure in the vicinity of the lock pin 112. FIG. 5A shows a mode at the time of fastening release, and FIG. 5B shows a mode at the time of fastening.

  The lock pin 112 is slidably disposed in the cylinder hole 122 that intersects the sliding hole 120. The lock pin 112 is always urged by the coil spring 116 toward the base end side of the rocker arm 102, that is, in a direction away from the movable cam follower 106.

  A groove 114 is formed in the lock pin 112 from the center to the tip side. The lower end of the movable cam follower 106 can be fitted into the groove 114. Furthermore, the bottom surface of the front end side of the groove 114 is notched so as to allow the movable cam follower 106 to slide in the vertical direction. On the other hand, the bottom surface of the central portion side (base end side) of the groove 114 is left so as to be in contact with the lower end of the movable cam follower 106.

  A space 118 on the proximal end side of the rocker arm 102 in the cylinder hole 122 and defined by the lock pin 112 is a hydraulic chamber into which hydraulic oil for operating the lock pin 112 is introduced. The hydraulic chamber 118 is connected to an oil passage 126 formed in the rocker arm 102. Further, the oil passage 126 is connected to an oil passage 124 formed in the rocker shaft 100, and hydraulic pressure in the hydraulic chamber 118 is adjusted by supplying and discharging hydraulic oil through the oil passages 124 and 126. The The lock pin 112 moves in the cylinder hole 122 according to the balance between the force based on the hydraulic pressure in the hydraulic chamber 118 and the biasing force of the coil spring 116, and the position shown in FIG. 5A and the position shown in FIG. It is designed to reciprocate between the two.

  When releasing the fastening between the rocker arm 102 and the movable cam follower 106, the hydraulic oil in the hydraulic chamber 118 is lowered by discharging the hydraulic oil from the hydraulic chamber 118. As a result, the lock pin 112 moves toward the proximal end side of the rocker arm 102 by the urging force of the coil spring 116 and comes to a position shown in FIG. 5A. At this time, since the lower end portion of the movable cam follower 106 is located at a portion where the bottom surface of the groove 114 of the lock pin 112 is cut out, sliding in the vertical direction is allowed.

  The pressing of the intake cam 26 a at this time is absorbed by the vertical sliding in the sliding hole 120 of the movable cam follower 106 and is not transmitted to the rocker arm 102. For this reason, the rocker arm 102 remains stationary without being rotated by the intake cam 26a, and the intake valve 12 also remains stopped in the closed state.

  On the other hand, when the rocker arm 102 and the movable cam follower 106 are fastened, hydraulic oil is supplied to the hydraulic chamber 118 to increase the hydraulic pressure in the hydraulic chamber 118. As a result, the lock pin 112 moves to the distal end side of the rocker arm 102 against the urging force of the coil spring 116 and comes to a position shown in FIG. 5B. At this time, the lower end portion of the movable cam follower 106 is positioned at a portion where the bottom surface of the groove 114 of the lock pin 112 is left. At this time, when the movable cam follower 106 is pushed down, the lower end surface thereof comes into contact with the bottom surface of the groove 114.

  At this time, the pressure of the intake cam 26 a is directly transmitted to the rocker arm 102 through the contact between the movable cam follower 106 and the lock pin 112. That is, at this time, the movable cam follower 106 and the rocker arm 102 are connected to each other and rotate together. In this case, the rocker arm 102 is rotated by the intake cam 26a, and the intake valve 12 is also opened / closed by the intake cam 26a.

  As described above, the variable valve operating device 52 controls the operation and stop of the intake valve 12 by controlling the supply of hydraulic oil to the hydraulic chamber 118 by controlling the electromagnetic valve provided in the hydraulic circuit. It can be controlled. This also applies to the variable valve device 54 on the exhaust side, and the variable valve device 54 can control the operation and stop of the exhaust valve 14. The mechanism of the variable valve operating devices 52 and 54 described above is an example of a means for stopping the intake valve 12 and the exhaust valve 14 in the closed state, and the intake valve 12 and the exhaust valve 14 using other mechanisms. May be stopped.

  The engine includes an ECU (Electronic Control Unit) 60 as its control device. Various devices such as the ignition plug 16, the throttle 38, the injector 40, the variable valve timing mechanism 50, and the variable valve gears 52 and 54 are connected to the output side of the ECU 50. On the input side of the ECU 60, in addition to the throttle sensor 64 and the air flow meter 66, a crank angle sensor 62 that outputs a signal corresponding to the rotation angle of the crankshaft 62, and a water temperature sensor 68 that outputs a signal corresponding to the cooling water temperature. Various sensors such as are connected. The ECU 50 drives each device according to a predetermined control program based on the output of each sensor.

  FIG. 6 is a flowchart showing a control routine executed by the ECU 60 in the present embodiment at the time of deceleration fuel cut and at the time of return from the deceleration fuel cut. The routine shown in FIG. 6 is periodically executed at every constant crank angle. In the first step 100 of this routine, information regarding the operating state of the engine is captured. Specifically, the engine speed ne is acquired from the signal of the crank angle sensor 62, and the load factor kl is acquired from the signal of the air flow meter 66. Further, the throttle opening degree ta is acquired from the signal of the throttle sensor 64, and the engine water temperature thw is acquired from the signal of the water temperature sensor 68.

  In step 102, it is determined whether or not an execution condition for deceleration fuel cut (deceleration F / C) is satisfied. More specifically, it is determined whether the throttle opening degree ta is closed to a predetermined idle opening degree ta0 or less. In the system of the present embodiment, when the deceleration fuel cut is executed, the throttle 38 is closed to an opening that is even smaller than the idle opening ta0 (an opening that is nearly fully closed). By closing the throttle 38 to a state close to full closure, the amount of intake air is greatly reduced, and a large amount of lean air that does not contain fuel flows through the catalyst 46 in a high temperature state.

  If the result of determination in step 102 is that the throttle opening degree ta is equal to or less than the idle opening degree ta0, that is, if the establishment of the deceleration F / C condition is recognized, engine control for deceleration fuel cut is performed. On the other hand, when the throttle opening degree ta is larger than the idle opening degree ta0, that is, when the deceleration F / C condition is not established, it is necessary to continue normal operation or return from the deceleration fuel cut. Engine control is performed.

  In the following, the case where the determination of the deceleration F / C condition is recognized in step 102 will be described first. If it is confirmed that the deceleration F / C condition is satisfied, first, the process of step 104 is executed. In step 104, fuel injection from the injector 40 is stopped for all cylinders. That is, the deceleration fuel cut is executed. In parallel with the stop of fuel injection, the variable valve timing mechanism 50 is controlled so that the valve timing VVT of the intake valve 12 becomes the target value vt2 during deceleration F / C.

  The target value vt2 at the time of deceleration F / C is a value (advance amount) of the valve timing VVT that should be realized during execution of the deceleration fuel cut. The target value vt2 for deceleration F / C is determined in relation to the engine speed ne. More specifically, the deceleration target value vt2 is set to 0 near the idling engine speed, and becomes larger as the engine speed ne becomes higher. The target value vt2 at the time of deceleration F / C is a target value used in a situation where the load factor kl is sufficiently small. The normal target value of the valve timing VVT is set to 0 in the entire rotation region under such a situation. Accordingly, the target value vt2 during deceleration F / C is set to become larger as the engine speed ne becomes higher than the normal target value.

  The system of this embodiment is configured such that the valve overlap period of the intake valve 12 and the exhaust valve 14 becomes longer as the valve timing VVT becomes larger. The longer the valve overlap period, the greater the amount of exhaust gas blowback from the exhaust port 20 to the intake port 18, that is, the amount of internal EGR. The following effects can be obtained by increasing the internal EGR amount.

  By closing the throttle 38 during deceleration, the inside of the intake manifold 32 and the intake port 18 downstream of the throttle 38 (hereinafter referred to as the intake pipe interior) is greatly reduced in negative pressure. When a large negative pressure is generated inside the intake pipe, the pressure in the combustion chamber 10 (in-cylinder pressure) also becomes negative due to the influence, and so-called oil rise occurs. For this reason, from the viewpoint of suppressing oil consumption, it is desirable that the intake pipe pressure (pressure in the intake manifold 32 and the intake port 18) during deceleration is not excessively negative. As a means for suppressing negative intake pipe pressure, it is effective to increase the amount of exhaust gas recirculated. Therefore, if the valve timing VVT is controlled in parallel with the execution of the deceleration fuel cut as described above and the internal EGR amount is increased, the increase in the intake pipe negative pressure accompanying the closing of the throttle 38 is suppressed, and the oil rises. Can be suppressed.

  However, due to the mechanism of the variable valve timing mechanism 50, the VVT actually matches vt2 after a command is issued to the variable valve timing mechanism 50 to make the valve timing VVT coincide with the target value vt2 during deceleration F / C. A certain amount of actuator operation time is required until this is achieved. That is, in the system of the present embodiment, after the target value vt2 at the time of deceleration F / C is determined, a certain amount of time (until the internal EGR amount sufficient to avoid the occurrence of excessive intake negative pressure is ensured ( Several cycles are required for engine rotation. For this reason, a time lag occurs after the throttle 38 is closed until the internal EGR amount increases, and the increase in the intake pipe negative pressure cannot be effectively suppressed during the time lag.

  Therefore, in this routine, until the internal EGR amount sufficiently increases, the control in steps 106 to 114 is performed in parallel with the control of the valve timing VVT as a means for suppressing the increase in the intake pipe negative pressure. Is done.

  First, in step 106, it is determined whether or not the flag XVVTa is 0. This flag XVVTa is held at 0 until the actual valve timing vtt becomes larger than the reference value A in the determination processing of step 110 executed later. The condition vtt> A used in the determination of step 110 is a condition for determining whether the actual valve timing vtt has changed to such an extent that a desired internal EGR amount is ensured. When vtt exceeds A in the determination in step 110, the flag XVVTa is set to 1 in the next step 112.

  While the flag XVVTa is 0, that is, while the actual valve timing vtt has not reached a level where a desired internal EGR amount is ensured, the process of step 108 is executed. In step 108, only one of the four cylinders # 1 to # 4 (for example, the first cylinder # 1) is stopped (one cylinder reduction operation). The suspension of operation is realized by stopping both the intake valve 12 and the exhaust valve 14 of the first cylinder # 1 in the closed state. As described above, since the variable valve gears 52 and 54 are provided for each cylinder, the intake valve 12 and the exhaust valve 14 can be controlled to operate and stop for each cylinder.

  While the change of the valve timing VVT requires several cycles, the switching from the operation of the valves 12 and 14 to the stop by the variable valve gears 52 and 54 is completed within one cycle at the latest. Then, by stopping both valves 12 and 14 in the closed state, the air consumption in the first cylinder # 1 is eliminated, and the air density in the surge tank 34 increases correspondingly, and the intake pipe negative pressure decreases. To do. Accordingly, the variable valve devices 52 and 54 are operated simultaneously with the execution of the deceleration fuel cut to stop the operation of the first cylinder # 1, thereby suppressing the increase in the intake pipe negative pressure immediately after the throttle 38 is closed. Is possible.

  In the next step 110, it is determined whether or not the actual valve timing vtt has become larger than the reference value A as described above. The flag XVVTa is held at 0 until the actual valve timing vtt becomes larger than the reference value A. Meanwhile, the determination result in step 106 is Yes, and the one-cylinder reduced cylinder operation (step 108) is continued due to the suspension of the operation of the first cylinder # 1.

  As the advance angle of the valve timing VVT advances, the actual valve timing vtt eventually becomes larger than the reference value A. When the actual valve timing vtt exceeds the reference value A, an internal EGR amount that can effectively suppress an increase in the intake pipe negative pressure is secured. Therefore, at this stage, it is possible to suppress an increase in the intake pipe negative pressure by only controlling the valve timing VVT and prevent the oil from rising without performing the one-cylinder reduction operation.

  Further, at the time of the one-cylinder reduction operation, the pumping loss of the engine is reduced as compared with the case where the cylinder deactivation is not performed because the air does not enter and exit from the first cylinder # 1. Since the deceleration performance of the engine during deceleration fuel cut depends on the magnitude of the pumping loss, in order to obtain a satisfactory deceleration feeling to the driver, stop the one-cylinder reduction operation at an early stage, I want to increase the pumping loss.

  Therefore, if the condition of vtt> A is satisfied in the determination of step 110 and the flag XVVTa is set to 1 in step 112, the process proceeds from step 106 to step 114, and the one-cylinder reduced cylinder operation is stopped. That is, both the intake valve 12 and the exhaust valve 14 of the first cylinder # 1 are switched from stop to operation by the operation of the variable valve devices 52 and 54 of the first cylinder # 1. This switching is completed within one cycle at the latest, similar to switching from operation to stop. By canceling the operation suspension of the first cylinder # 1, the pumping loss of the engine increases, and higher deceleration performance can be obtained.

  Note that the processing of step 116 is executed while the deceleration fuel cut is being executed. In step 116, the flag XFC is set to 1 and the flag XVVTb is reset to 0. The meanings of the flag XFC and the flag XVVTb will be described later.

  FIG. 7 is a time chart showing the operation at the time of the deceleration fuel cut described above, that is, the operation in the case where the deceleration F / C condition is confirmed at step 102. FIG. 7 shows the operations of (A) the advance amount of the valve timing VVT, (B) the number of reduced cylinders, and (C) the throttle opening, in order from the top. And the time change of (D) intake pipe negative pressure as a control result is shown in the lowest stage.

  In FIG. 7, a thick solid line indicates an operation and a control result by executing this routine. On the other hand, the broken line shows the operation and control result by the first comparison control method as a comparative example, and the thin solid line shows the operation and control result by the second comparison control method. In the first comparison control method and the second comparison control method, the advance angle of the valve timing VVT and the cylinder reduction operation are not executed as in this routine. The difference between the first comparison control method and the second comparison control method is the throttle opening at the time of deceleration fuel cut. In the first comparative control method, the throttle is closed to the idle opening, whereas in the second comparative control method, the throttle is closed to an opening smaller than the idle opening as in the execution of this routine. . Hereinafter, the operations and effects obtained by this routine will be described while comparing with the control results of these comparative examples.

During deceleration, the throttle 38 is controlled in the closing direction in conjunction with the accelerator pedal being turned off, and the throttle opening is quickly reduced. When the throttle opening decreases to the idle opening (time point t ₁ ), fuel cut is executed using that as a trigger. When the fuel cut is executed, the ECU 60 issues a command to the valve timing variable mechanism 50 to make the valve timing VVT coincide with the target value vt2 at the time of deceleration F / C, and at the same time, the variable valve system for the first cylinder # 1 A command for stopping valves 12 and 14 is issued to 52 and 54.

  There is a time lag before the valve timing VVT actually starts to change in response to a command from the ECU 60. On the other hand, switching from the operation of the valves 12 and 14 to the stop by the variable valve gears 52 and 54 is executed promptly after a command from the ECU 60. Thus, when the fuel cut is executed, the operation of the first cylinder # 1 is stopped at substantially the same timing, and the one-cylinder reduced cylinder operation is started.

  In this routine, the throttle 38 is closed to a predetermined opening smaller than the idle opening. As the throttle 38 is closed, the amount of intake air can be reduced to suppress the deterioration of the catalyst 46, but the intake pipe negative pressure increases. In the first comparative control method, the increase in the intake pipe negative pressure is suppressed by restricting the throttle 38 to the idle opening, but the intake air amount increases correspondingly, and the catalyst 46 is likely to deteriorate. On the other hand, when the throttle 38 is closed to an opening smaller than the idle opening as in the second comparative control method, the intake pipe negative pressure exceeds the allowable oil rise negative pressure as much as the intake air amount can be reduced. It will increase. The oil rising allowable negative pressure corresponds to a limit negative pressure that can keep the oil rising amount into the combustion chamber 10 at an allowable amount.

  On the other hand, according to this routine, the increase in the intake pipe negative pressure is suppressed by executing the one-cylinder cylinder reduction operation, and the throttle 38 is closed to an opening smaller than the idle opening. In addition, the intake pipe negative pressure is maintained at or below the allowable negative pressure for oil rising. As a result, it is possible to prevent oil from rising into the combustion chamber 10 due to an increase in the intake pipe negative pressure while limiting the amount of intake air to suppress the deterioration of the catalyst 46.

After the fuel cut is executed and the one-cylinder reduction operation is executed, the valve timing VVT starts to change after a while (time point t ₂ ). As the valve timing VVT advances, the valve overlap period increases and the internal EGR amount increases. As a result, the intake pipe negative pressure also decreases as the valve timing VVT changes.

In this routine, when the actual valve timing vtt becomes larger than the reference value A, the ECU 60 issues a command for operating the valves 12 and 14 to the variable valve gears 52 and 54 of the first cylinder # 1. (Time t ₃ ). Switching from the stop to the operation of the valves 12 and 14 by the variable valve gears 52 and 54 is performed promptly after a command from the ECU 60. Thereby, the operation of the first cylinder # 1 is resumed and the one-cylinder reduced cylinder operation is ended.

  When the operation of the first cylinder # 1 is restarted, the air in the surge tank 34 is consumed correspondingly, and the intake pipe negative pressure increases. However, the reference value A is set to a value that secures an internal EGR amount that can prevent the oil from rising, so even if the intake pipe negative pressure increases with the end of the one-cylinder reduction cylinder operation, The intake pipe negative pressure will not exceed the allowable negative pressure. As a result, the deterioration of the catalyst 46 and the increase in the intake pipe negative pressure are suppressed, and higher deceleration performance can be obtained by increasing the pumping loss of the engine.

  Next, returning to the flowchart of FIG. 6 again, the case where the deceleration F / C condition is not satisfied in the determination of step 102 will be described. If the deceleration F / C condition is not satisfied, first, the process of step 118 is executed. Examples of the case where the deceleration F / C condition is not satisfied include a case where the deceleration fuel cut is not executed (for example, during steady operation or acceleration operation) and a case where the vehicle is returning from the deceleration fuel cut. The return from the deceleration fuel cut is not only when the accelerator pedal is depressed by the driver, but also when the engine speed drops below a predetermined reference speed or when the temperature of the catalyst 46 drops below a predetermined reference temperature. And so on (hereinafter referred to as natural recovery).

  In step 118, it is determined whether or not the deceleration F / C condition is not satisfied due to a slow recovery from the deceleration fuel cut or a natural return. Whether or not the return is due to slow acceleration can be determined from the throttle opening or the amount of change in the throttle opening.

  When the deceleration F / C condition is not satisfied due to a reason other than the slow acceleration return or the natural return, the processes of step 134 and step 136 are executed. In step 134, a normal operation in which all cylinders are operated is executed. For example, in the case of return from the deceleration fuel cut by sudden acceleration, all cylinders are operated without performing the one-cylinder reduction operation, and all cylinders are returned from the fuel cut at the same time. In the next step 136, the valve timing VVT is controlled to a target value corresponding to the engine operating state taken in in step 100.

  If the deceleration F / C condition is not satisfied due to slow acceleration recovery or natural recovery, it is further determined whether or not the flag XFC is 1 (step 120). The flag XFC is a flag indicating that the deceleration fuel cut is being executed or the engine is being controlled for returning from the deceleration fuel cut. And when returning completely from the deceleration fuel cut, it is reset to 0 by the process of step 132 described later. After returning from the deceleration fuel cut, the condition of step 120 is not satisfied, and in this case, engine control is performed by the processing of step 134 and step 136.

  If the flag XFC is 1, it is further determined whether or not the flag XVVTb is 0 (step 122). While the flag XVVTb is 0, engine control is performed by the processing of step 124 and step 126 described later. When the flag XVVTb is 1, the engine control method is switched to engine control by the processing of step 134 and step 136. It is done. When the return control from the deceleration fuel cut is started, the initial value of the flag XVVTb is 0.

  In step 124, the one-cylinder reduced cylinder operation is performed, and only one of the four cylinders # 1 to # 4 (for example, the first cylinder # 1) is stopped. At the same time, the fuel cut is released for the other cylinders # 2 to # 4 excluding the deactivated cylinder, and the fuel injection from the injector 40 is resumed in those cylinders # 2 to # 4. As described above, the following effects can be obtained by performing the one-cylinder reduction operation.

  At the time of slow acceleration recovery from the deceleration fuel cut, or at the time of natural recovery, the throttle 38 has not yet been opened wide (for example, about the idle opening degree), so the amount of air sucked through the throttle 38 is small. In addition, the valve timing VVT is advanced by the control during the deceleration fuel cut, and the internal EGR amount increases. If the fuel cut is canceled for all the cylinders in this state, misfire may occur due to a shortage of new gas, and exhaust emission may deteriorate. As a means for avoiding misfire, it is conceivable to retard the valve timing VVT. This is because the valve overlap period of the intake valve 12 and the exhaust valve 14 can be shortened and the internal EGR amount can be reduced by advancing the valve timing VVT.

  However, as described above, after the command for delaying the valve timing VVT is issued to the variable valve timing mechanism 50 on the mechanism of the variable valve timing mechanism 50, the VVT actually changes to avoid misfire. A certain amount of actuator operation time is required until the internal EGR amount is reduced as much as possible. For this reason, even if the variable valve timing mechanism 50 is operated immediately after returning from the deceleration fuel cut, a time lag occurs until the internal EGR amount is sufficiently reduced, and misfire is effectively avoided during the time lag. I can't.

  Therefore, in this routine, the one-cylinder reduced cylinder operation is performed as a means for reliably avoiding misfire when returning from the deceleration fuel cut. By performing the one-cylinder reduction operation, the air consumption in the first cylinder # 1 is eliminated, and the intake pipe negative pressure is reduced correspondingly. As a result, in the operating cylinders # 2 to # 4 in which the fuel cut is released, the amount of new gas sucked into the combustion chamber 10 increases, and misfires in these cylinders # 2 to # 4 are avoided.

  In step 126, the variable valve timing mechanism 50 is controlled so that the valve timing VVT is advanced toward the target value during normal operation. Then, in the next step 128, it is determined whether or not the actual valve timing vtt has become smaller than the reference value B. The reference value B is a value smaller than the reference value A described above. The condition of vtt <B used in the determination of step 128 is a condition for determining whether the internal EGR amount has decreased to such an extent that misfire can be avoided without performing the one-cylinder cylinder reduction operation.

  The flag XVVTb is held at 0 until the actual valve timing vtt becomes smaller than the reference value B in the determination of step 128. Meanwhile, the determination result in step 122 is Yes, and the one-cylinder reduced cylinder operation (step 124) by the operation suspension of the first cylinder # 1 is continued. When vtt falls below B in the determination of step 128, the flag XVVTb is set to 1 in the next step 130.

  As the retard of the valve timing VVT advances, the actual valve timing vtt eventually becomes smaller than the reference value B. When the actual valve timing vtt falls below the reference value B, the internal EGR amount decreases to such an extent that misfire can be avoided. Therefore, at this stage, it is possible to avoid misfire only by controlling the valve timing VVT without performing the one-cylinder reduction operation.

  Therefore, if the condition of vtt <B is satisfied in the determination of step 128 and the flag XVVTb is set to 1 in step 130, the process proceeds from step 122 to step 134, and the one-cylinder reduced cylinder operation is stopped. That is, both the intake valve 12 and the exhaust valve 14 of the first cylinder # 1 are switched from stop to operation by the operation of the variable valve devices 52 and 54 of the first cylinder # 1. Then, the fuel cut is also released for the first cylinder # 1 for which the suspension of operation has been released, similarly to the other cylinders # 2 to # 4.

  In this way, with the internal EGR amount sufficiently reduced, the cylinder deactivation and the fuel cut of the first cylinder # 1 are canceled, so that it is possible to completely return from the deceleration fuel cut without causing misfire. become. After complete recovery from the deceleration fuel cut, the valve timing VVT is controlled to a target value corresponding to the engine operating state (step 136).

  Note that the flag XFC is reset to 0 when returning completely from the deceleration fuel cut, that is, when the condition of vtt <B is satisfied and the flag XVVTb is set to 1 in step 130. The flag XFC is also reset to 0 when the normal operation (step 134 and step 136) after complete recovery from the deceleration fuel cut is performed. When the flag XFC is reset to 0, the flag XVVTa is simultaneously reset to 0 (step 132).

  As described above, according to the routine shown in FIG. 6, at the time of the deceleration fuel cut, the intake air amount is reduced by adjusting the throttle 38 to the closed side, thereby suppressing the deterioration of the catalyst 46. At this time, since the operation of the first cylinder # 1 is suspended by the one-cylinder reduction operation, the air consumption by the first cylinder # 1 is eliminated, and the air density in the surge tank 34 increases and decreases accordingly. As a result, an increase in the intake pipe negative pressure is suppressed, and an increase in oil due to an increase in the negative pressure in the combustion chamber 10 is prevented.

  Thereafter, when the valve timing VVT is advanced by the variable valve timing mechanism 50 and the internal EGR amount is increased to a desired amount, the suspension of the first cylinder # 1 is released, and thereafter the intake pipe negative is increased by the increase of the internal EGR amount. Increase in pressure is suppressed. By canceling the operation suspension of the first cylinder # 1, the pumping loss of the engine is increased correspondingly, and higher deceleration performance can be obtained.

  Further, according to the routine shown in FIG. 6, when returning from the deceleration fuel cut, the operation of the first cylinder # 1 is stopped by the one-cylinder reduction cylinder operation, and the fuel cut is performed for the cylinders # 2 to # 4 other than the idle cylinder. In the released state, the internal EGR amount is reduced. By stopping the operation of the first cylinder # 1, the intake pipe negative pressure is greatly reduced, and the amount of new gas sucked into the combustion chamber 10 is increased in the cylinders # 2 to # 4 other than the deactivated cylinder. As a result, misfires in the cylinders # 2 to # 4 in which the fuel cut is released are avoided. Then, in the state where the internal EGR amount is sufficiently reduced, the cylinder deactivation and the fuel cut are also released for the first cylinder # 1, thereby making it possible to completely return from the deceleration fuel cut without causing misfire.

  Further, according to the routine shown in FIG. 6, when a heavy load is required for the engine when returning from the deceleration fuel cut by sudden acceleration, that is, when returning from the deceleration fuel cut, the fuel cut is immediately released for all the cylinders. Is done. As a result, it is possible to quickly output torque according to the required load. Further, in this case, since the throttle 38 is largely opened according to the required load, a sufficient amount of new gas is sucked into the combustion chamber 10. Therefore, misfire in the cylinder from which the fuel cut has been released can be avoided without performing a one-cylinder reduction operation or retarding the valve timing VVT.

  In the embodiment described above, the “fuel cut means” in the present invention is realized by the ECU 60 performing fuel cut when the engine is decelerated, and the “intake air amount adjusting means” is controlled by controlling the throttle 38. Is realized, “recirculation amount adjusting means” is realized by controlling the valve timing variable mechanism 50, and “cylinder deactivation means” is realized by controlling the variable valve operating devices 52, 54.

  In the embodiment described above, the “fuel cut determination means” and the “fuel cut return determination means” are realized by the ECU 60 executing the processing of step 102 of the routine shown in FIG. Further, by executing the processing of step 118, “means for determining whether the required load is high load or low load” is realized.

  Further, in the above-described embodiment, the “control means” in the present invention is realized by the ECU 60 executing the routine shown in FIG. In particular, by executing the processing of step 104, “first control”, “second control”, and “third control” are executed, and the processing of steps 106, 108, 110, 112, and 114 is executed. As a result, the “fourth control” is executed. Further, “fifth control” and “sixth control” are executed by executing the process of step 124, and “seventh control” is executed by executing the process of step 126. The “eighth control” is executed by executing the processes 128, 130, and 134. Further, the “ninth control” is executed by executing the processing of steps 118 and 134.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and modifications can be made without departing from the spirit of the present invention. For example, the following modifications may be made.

  In the above-described embodiment, when cylinder deactivation is performed by the reduced cylinder operation, both the intake valve 12 and the exhaust valve 14 are stopped in the closed state by the variable valve devices 52 and 54. Only one of the valves 14 may be stopped in a closed state. If at least one of the intake valve 12 and the exhaust valve 14 is stopped in the closed state, air consumption in the cylinder is eliminated, so that an increase in the intake pipe negative pressure can be suppressed.

  Further, in the above-described embodiment, when performing the reduced cylinder operation, the operation of only one cylinder is suspended, but the operation of a plurality of cylinders may be suspended. The magnitude of the intake pipe negative pressure realized by cylinder deactivation can be controlled by the number of cylinders deactivated. Also, when stopping the operation of multiple cylinders at the time of deceleration fuel cut, the cylinder stoppage is canceled step by step according to the increase of the internal EGR amount accompanying the advance of the valve timing VVT. Also good. Similarly, when stopping the operation of multiple cylinders when returning from the deceleration fuel cut, the cylinder pauses are released step by step according to the decrease in the internal EGR amount accompanying the retard of the valve timing VVT. You may make it go.

  In the above-described embodiment, the valve timing of the intake valve 12 is controlled by the valve timing variable mechanism 50 to change the valve overlap period, and as a result, the internal EGR amount is changed. The method of changing the amount is not limited to such a method. For example, when the exhaust valve 14 is also provided with a variable valve timing mechanism, the valve timing of the exhaust valve 14 may be controlled to change the valve overlap period, and as a result, the internal EGR amount may be changed.

  Further, when the valve timing of the exhaust valve 14 can be variably controlled, the method of changing the internal EGR amount is not limited to the method of increasing or decreasing the valve overlap period. When the valve closing timing of the exhaust valve 14 is set to the crank angle region before the exhaust top dead center, the amount of residual gas trapped in the combustion chamber 10 in the exhaust stroke increases or decreases by moving the valve closing timing back and forth. For this reason, the internal EGR amount may be increased or decreased by adjusting the closing timing of the exhaust valve 14 in the crank angle region before the exhaust top dead center.

  In the above-described embodiment, the increase in the intake pipe negative pressure is suppressed by increasing the internal EGR amount, but the suppression method is not limited to this. That is, the exhaust passage (for example, the exhaust pipe 44) and the intake passage (for example, the intake manifold 32) are connected by the EGR passage, and the opening degree of the EGR valve disposed in the EGR passage is controlled to change from the exhaust passage to the intake passage. The same function may be realized by increasing the flow rate (external EGR amount) of the supplied exhaust gas.

  In the embodiment described above, the magnitude of the negative pressure and the flow rate of the air flowing through the catalyst 46 are controlled by controlling the throttle opening, but the control target is limited to this. It is not a thing. That is, the magnitude of the negative pressure and the flow rate of the air flowing through the catalyst 46 can be controlled by increasing or decreasing the intake air amount. Therefore, the same function as that of the embodiment can be achieved not only by controlling the throttle opening but also by controlling an element that changes the intake air amount. Specifically, if the engine is a throttleless engine, it may be an engine having an idle speed control (ISC) valve that bypasses the throttle by changing the lift amount, operating angle, valve opening timing, etc. of the intake valve. For example, the same function as that of the embodiment can be realized by changing the flow rate of the ISC valve passing therethrough.

1 is a diagram showing a schematic configuration of an internal combustion engine to which a control device as an embodiment of the present invention is applied. It is the figure which looked at the cylinder head part of the internal combustion engine shown in Drawing 1 from the upper part. It is a perspective view which shows schematic structure of the variable valve apparatus in embodiment of this invention. It is a figure which shows the side part cross-section of the variable valve apparatus shown in FIG. It is a figure which shows the side part cross-section structure of the lock pin vicinity of the variable valve apparatus shown in FIG. 3, and is a figure which shows the aspect at the time of fastening cancellation | release. It is a figure which shows the side part cross-section structure of the lock pin vicinity of the variable valve apparatus shown in FIG. 3, and is a figure which shows the aspect at the time of fastening. It is a flowchart which shows the routine of control at the time of the deceleration fuel cut and the return at the time of the deceleration fuel cut performed in embodiment of this invention. It is a time chart which shows an example of the operation | movement implement | achieved by performing the routine shown in FIG.

Explanation of symbols

4 Cylinder head 6 Cylinder block 8 Piston 10 Combustion chamber 12 Intake valve 14 Exhaust valve 16 Spark plug 18 Intake port 20 Exhaust port 24 Crankshaft 26 Intake camshaft 26a Intake cam 28 Exhaust camshaft 28a Exhaust cam 32 Intake manifold 34 Surge tank 38 Throttle 40 Injector 42 Exhaust manifold 46 Catalyst 50 Variable valve timing mechanism 52 Variable valve device 54 on the intake side Variable valve device 60 on the exhaust side ECU
62 Crank angle sensor 64 Throttle sensor 66 Air flow meter 68 Water temperature sensor

Claims (5)

A control device for an internal combustion engine having a plurality of cylinders,
Fuel cut means for performing fuel cut on the plurality of cylinders;
An intake air amount adjusting means for adjusting the intake air amount;
A recirculation amount adjusting means for adjusting a recirculation amount of exhaust gas;
Cylinder deactivation means for deactivating the cylinder by closing at least one of the intake valve and the exhaust valve for at least one of the plurality of cylinders;
Fuel cut determination means for determining whether a fuel cut condition is satisfied at the time of deceleration of the internal combustion engine;
When the fuel cut condition is satisfied, the first control for operating the intake air amount adjusting means on the side to reduce the intake air amount, and the fuel cut means for operating the fuel cut for the plurality of cylinders. A second control for controlling, a third control for operating the recirculation amount adjusting means to increase the exhaust gas recirculation amount, and at least one cylinder among the plurality of cylinders by operating the cylinder deactivation means And a fourth control for canceling the cylinder deactivation by the cylinder deactivation means when the exhaust gas recirculation amount is increased to a desired amount,
A control device for an internal combustion engine, comprising:   2. The control apparatus for an internal combustion engine according to claim 1, wherein the recirculation amount adjusting means is a variable valve timing mechanism that changes an overlap period of the intake valve and the exhaust valve.   2. The control apparatus for an internal combustion engine according to claim 1, wherein the recirculation amount adjusting means is an EGR valve disposed in an EGR passage connecting the exhaust passage and the intake passage. A fuel cut return determination means for determining the establishment of a return condition from the fuel cut;
The control means activates the cylinder deactivation means to deactivate at least one of the plurality of cylinders when the fuel cut return condition is satisfied, and deactivates among the plurality of cylinders. Sixth control for canceling fuel cut by the fuel cut means for cylinders other than the cylinder, seventh control for operating the recirculation amount adjusting means to reduce the exhaust gas recirculation amount, and exhaust gas recirculation When the amount is reduced to a desired amount, the cylinder deactivation by the cylinder deactivation unit is canceled, and the eighth control is performed for canceling the fuel cut by the fuel cut unit for the cylinders deactivated among the plurality of cylinders. The control device for an internal combustion engine according to any one of claims 1 to 3, wherein the control device is an internal combustion engine. Means for determining whether the load required for the internal combustion engine upon return from fuel cut is high or low;
The control means executes the fifth to eighth controls when the required load on the internal combustion engine is low, and when the required load on the internal combustion engine is high, The control apparatus for an internal combustion engine according to claim 4, wherein ninth control for canceling fuel cut by the fuel cut means is executed for the plurality of cylinders.

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