JP5772704B2 - Control device for internal combustion engine - Google Patents

Description

  The present invention relates to a control device for an internal combustion engine. More specifically, the present invention is suitable as a control device for an internal combustion engine having a variable valve mechanism that varies the valve operating characteristics of an exhaust valve of a multi-cylinder internal combustion engine.

  One method for improving the combustion efficiency of an internal combustion engine is to use a large amount of cooled EGR gas (cooled EGR). By utilizing EGR in large quantities, it is possible to reduce pump loss and improve knocking at a high load, and to improve the equal volume.

  However, in order to realize the introduction of a large amount of EGR gas, it is desirable to minimize the pressure loss in the EGR path. One effective technique for this purpose is to enlarge the diameter of the EGR valve. However, the enlargement of the EGR valve diameter may cause a deceleration misfire or the like.

  As another method for realizing a large amount of EGR gas introduction, it is conceivable to improve the potential of the air introduction amount. If the potential of the air introduction amount increases, the throttle opening can be reduced accordingly. Therefore, the EGR gas introduction part on the intake side can be set to a negative pressure, and the EGR gas introduction amount can be increased. In order to realize a large amount of EGR gas introduction, it is conceivable to lower the EGR gas temperature. By setting the EGR gas to a low temperature, the density of the EGR gas can be increased, and the amount of EGR gas introduced can be increased.

  By the way, Patent Document 1 discloses a variable valve mechanism having a high speed cam and a low speed cam that open and close an intake valve or an exhaust valve of an internal combustion engine at different operating angles. The system of this patent document 1 changes the lift amount and valve opening period of an intake / exhaust valve by switching the cam which opens and closes an intake / exhaust valve according to an operating condition with a variable valve mechanism. For example, in this system, the intake / exhaust valve is controlled by the low-speed cam in the low-speed operation state. When the intake / exhaust valve is controlled by the low-speed cam, the operating angle of the intake / exhaust valve is set to be narrower than when the intake / exhaust valve is controlled by the high-speed cam. Thereby, the valve overlap amount in the low speed operation state is reduced. By utilizing the low speed cam having a narrow working angle described in Patent Document 1, it is possible to suppress exhaust interference between the cylinders, thereby improving the potential of the air introduction amount.

JP 2011-38439 A JP 2004-270538 A

  For example, when the intake valve is opened and closed by a cam having a narrow operating angle in the system of Patent Document 1, the intake valve is opened near the top dead center of the exhaust (intake). Accordingly, in order to reduce the valve overlap amount, the exhaust valve inevitably closes to the exhaust top dead center at the closing timing, and the opening timing is in the middle of the expansion stroke. For this reason, it is difficult to reduce the temperature of the burned gas by securing the expansion ratio. Therefore, it is difficult to introduce a large amount of EGR gas by reducing the temperature of the EGR gas.

  An object of the present invention is to provide a control apparatus for an internal combustion engine which is improved in order to solve the above-mentioned problems and which can introduce a large amount of EGR and improve the thermal efficiency over the entire range from a low load to a high load. .

In order to solve the above-described object, the present invention is an internal combustion engine that is applied to a multi-cylinder internal combustion engine that includes an EGR device for recirculating a part of the exhaust gas of the internal combustion engine as EGR gas to the intake system of the internal combustion engine. A control device,
A variable valve mechanism that has a first cam and a second cam corresponding to each exhaust valve of each cylinder, and that controls valve operating characteristics of the exhaust valve;
Means for detecting or predicting the occurrence of knocking in the internal combustion engine;
Means for controlling the operating angle of the exhaust valve to the operating angle of the first cam when occurrence of knocking is not detected or predicted;
Means for controlling the exhaust valve to an operating angle by the second cam when occurrence of knocking is detected or predicted.
Here, the first cam is a cam that opens the exhaust valve on the advance side from the expansion bottom dead center and closes the exhaust valve on the retard side from the exhaust top dead center,
The second cam is a cam that opens the exhaust valve at the expansion bottom dead center and closes the exhaust valve at the exhaust top dead center.

  Here, the “predetermined period including zero” is used. However, the “predetermined period” is more than the overlapping period of the exhaust valve opening period between different cylinders when the exhaust valve is controlled by at least the first cam. It is a short period. In the “predetermined period”, even when the exhaust valve opening period overlaps between different cylinders due to the second cam, the exhaust interference is smaller than at least when the exhaust valve is opened and closed by the first cam. Is set to a period.

  Therefore, in the present invention, the second cam may be a cam that opens the exhaust valve at the expansion bottom dead center and closes the exhaust valve at the exhaust top dead center. Here, in the second cam, the valve opening timing is the expansion bottom dead center and the valve closing timing is the exhaust top dead center. However, in the present invention, the exhaust interference between the cylinders causes the exhaust valve to be opened and closed by the first cam. Therefore, the exhaust valve may be opened near the expansion top dead center and closed near the exhaust top dead center by the second cam.

  In the present invention, the means for detecting or predicting the occurrence of knocking predicts the occurrence of knocking when the load on the internal combustion engine is greater than the load on the internal combustion engine at the knocking occurrence point where occurrence of knocking is estimated. It is good also as what to do.

  Further, the present invention provides a throttle valve opening degree of the internal combustion engine set for a certain load when the exhaust valve is controlled by the second cam, and the exhaust valve is controlled by the first cam. Further, it may further comprise means for setting an opening smaller than the opening of the throttle valve set for a load equal to a certain load.

  According to the present invention, when the occurrence of knocking is detected or predicted, the exhaust valve is opened and closed by the second cam having a small operating angle. Thereby, since the exhaust interference between cylinders is suppressed, the potential of the air introduction amount can be increased. Therefore, the intake negative pressure in the EGR introduction part of the intake system can be increased. Further, since the expansion ratio can be increased, the temperature of the EGR gas can be reduced and the EGR gas density can be increased. Accordingly, even in a region where occurrence of knocking is detected or predicted, a large amount of EGR can be introduced, and thermal efficiency can be improved by improving knocking.

  Further, when the occurrence of knocking is not detected or predicted, the exhaust valve is opened by the first cam having a larger operating angle than the second cam. Thereby, the introduction of the internal EGR is promoted by utilizing the exhaust interference between the cylinders, and the pump loss can be reduced by increasing the throttle opening for the same torque (load). Therefore, the thermal efficiency of the internal combustion engine can be improved.

It is a schematic diagram for demonstrating the whole structure of the system in embodiment of this invention. It is a figure for demonstrating control of the intake / exhaust valve in embodiment of this invention. It is a figure for demonstrating control of the intake / exhaust valve in embodiment of this invention. It is a figure for demonstrating control of the throttle valve and EGR valve in embodiment of this invention. It is a flowchart for demonstrating the routine of control which a control apparatus performs in embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof is simplified or omitted.

Embodiment.
FIG. 1 is a diagram for explaining the overall configuration of a system according to an embodiment of the present invention. The system shown in FIG. 1 has an internal combustion engine 2. A plurality of cylinders 10 are arranged in the internal combustion engine 2. The internal combustion engine 2 is a spark ignition internal combustion engine, and a spark plug 12 is installed in each cylinder head of each cylinder 10. The internal combustion engine 2 of the present embodiment has four cylinders, and the ignition order is the order of # 1, # 3, # 4, and # 2.

  Two intake ports 14 and two exhaust ports 16 communicate with the combustion chamber of each cylinder 10. Each of the two intake ports 14 is provided with an intake valve 18 that opens and closes the intake port 14 with respect to the combustion chamber. Each of the two exhaust ports 16 is provided with an exhaust valve 20 that opens and closes the exhaust port 16 with respect to the combustion chamber.

  The exhaust valve 20 is connected to a two-stage variable valve mechanism 22 (VVT). The VVT 22 can change the phase of the exhaust valve 20 of each cylinder 10 and can change the working angle in two stages. Here, the working angle means a rotation angle of the crankshaft during a period in which the valve body (exhaust valve 20) moves from the most closed position to the most open position.

  Although illustration of a specific configuration is omitted, the VVT 22 includes two cams, a first cam and a second cam, for opening and closing the exhaust valve 20 at different operating angles. The first cam is a medium operating angle cam, and the second cam is a narrow operating angle cam having a smaller operating angle than the first cam. The VVT 22 can change the operating angle of the exhaust valve 20 by switching the cam that controls the exhaust valve 20 to either the first cam or the second cam. Various mechanisms for switching the cam in the VVT 22 and a mechanism for transmitting the cam pressing force to the exhaust valve 20 are known, and a detailed description thereof is omitted here. In addition, this system may be configured such that a variable valve mechanism similar to the VVT 22 is also provided for the intake valve 18 so that the valve characteristic of the intake valve 18 is variable.

  Two intake ports 14 of each cylinder 10 are gathered together on the upstream side, and a fuel injection valve 24 is attached to the gathering portion of the intake ports 14. A branch pipe portion of a common intake manifold 26 is connected to an upstream end portion of the intake port 14 of each cylinder 10. A surge tank 28 is installed upstream of the branch pipe portion of the intake manifold 26. The intake manifold 26 is connected to the intake pipe 30 on the upstream side of the surge tank 28. A throttle valve 32 is disposed in the intake pipe 30.

  On the other hand, the two exhaust ports 16 of each cylinder 10 are gathered together on the downstream side. A branch pipe portion of the exhaust manifold 36 communicates with the downstream end portion of the collecting portion of the exhaust port 16. The branch pipe part of the exhaust manifold 36 gathers in one collecting pipe part on the downstream side, and the collecting pipe part communicates with the catalyst 38.

  This system includes an EGR device 40. The EGR device 40 is a device for recirculating a part of the exhaust gas discharged from the internal combustion engine 2 to the intake side and introducing it again to the combustion chamber of each cylinder 10. Specifically, the EGR device 40 includes an EGR pipe 42 (EGR passage). The EGR pipe 42 is connected to the collecting pipe portion of the exhaust manifold 36 at one end. The other end side of the EGR pipe 42 is branched into four branch pipes. Each of the branch pipes of the EGR pipe 42 is connected at its end to a collecting part upstream of the intake valve 18 of the intake port 14 of each cylinder 10.

  The EGR pipe 42 is provided with an EGR cooler 44 and an EGR valve 46. The EGR cooler 44 has a function of cooling the EGR gas that circulates in the EGR pipe 42. The EGR valve 46 is a valve that opens and closes the EGR pipe 42.

  The system further includes a control device 50. Various sensors of the internal combustion engine 2 are connected to the input side of the control device 50 in addition to the Ne sensor 52 and the KCS (knock control system) 54. The output side of the control device 50 is connected to an actuator such as a fuel injection valve 24, a throttle valve 32, a VVT 22, an EGR valve 46, and other various mechanisms and valves. The control device 50 executes predetermined programs on the basis of input information from various sensors, and operates various actuators and the like, thereby executing various controls programmed for the operation of the internal combustion engine 2.

  The control performed by the control device 50 in the present embodiment includes control of the intake valve 18, the exhaust valve 20, the throttle valve 32, and the EGR valve 46. FIGS. 2 and 3 are diagrams for explaining the valve operating characteristics of the intake / exhaust valves 18 and 20 in the embodiment of the present invention. FIG. 2 shows that the exhaust valve 20 is controlled to a medium operating angle by the first cam. 2 shows an example in which the exhaust valve 20 is controlled to a narrow operating angle by the second cam. 2 and 3, the horizontal axis represents the crank angle, the lower side of the vertical axis represents the valve lift, and the upper side represents the exhaust pulsation. 2 and 3, only the valve operating characteristics of the # 1 cylinder and the # 3 cylinder in which the ignition order is continuous are shown, but in this embodiment, the exhaust valves 20 of each cylinder 10 have the same operation. It shall be controlled by valve characteristics.

  As shown in FIG. 2, when the exhaust valve 20 is controlled in the medium working angle mode by the first cam, the valve opening timing (hereinafter also referred to as “EVO”) of the exhaust valve 20 is in the middle of the expansion stroke, and the valve is closed. The timing (hereinafter also referred to as “EVC”) is in the middle of the intake stroke. Therefore, as shown in FIG. 2A, the opening period of the exhaust valve 20 of a certain cylinder (# 1 cylinder in FIG. 2) and the exhaust valve 20 of the next cylinder (# 3 in FIG. 2) to be ignited next time. There is a period that overlaps with the valve opening period. Accordingly, exhaust interference occurs due to blowdown of the next cylinder with respect to a certain cylinder, and the introduction of internal EGR into the cylinder is promoted.

On the other hand, as shown in FIG. 3, when the exhaust valve 20 is controlled in the narrow operating angle mode by the second cam, EVO is set to the vicinity of the expansion bottom dead center, and EVC is set to the vicinity of the exhaust top dead center. For example, as shown in FIG. 3B, the EVC of a certain cylinder (# 1 in FIG. 3) and the EVO of another cylinder (# 3 is illustrated in FIG. 3) are almost simultaneously, and the exhaust valve 20 is between the cylinders. There is no overlap or very little overlap during the valve opening period. Therefore, exhaust interference between cylinders is suppressed, and the air amount potential is improved. Therefore, when comparing between the same intake air amounts, the throttle opening can be made small and the intake negative pressure can be increased. That is, the EGR pipe 42 is connected and the pressure at the portion where the EGR gas is introduced can be reduced, and a large amount of EGR can be introduced. Further, according to the second cam, EV O is set to be in the vicinity of the expansion bottom dead center. Thereby, since a high expansion ratio can be secured, the temperature of the EGR gas can be reduced. Therefore, the introduction of a large amount of cooled EGR can be realized by controlling to the narrow working angle mode by the second cam.

  By the way, switching between the first cam and the second cam is performed as follows. First, when the exhaust valve 20 is controlled by an intermediate action, the occurrence of knocking is detected by the KCS 54. A second cam with a narrow operating angle is used in a region where the load is larger than the knock generation point with a load when the knock occurs (hereinafter also referred to as “knock generation point”), and in a region where the load is below the knock generation point. It is assumed that a first cam having a medium working angle is used. By switching to the second cam having a narrow operating angle at the knock generation point, knocking in a region of higher load than the knock generation point is improved. Therefore, the thermal efficiency in this region can be further increased.

  FIG. 4 is a diagram for explaining control of other valves (EGR valve 46 and throttle valve 32) and the like when the exhaust valve 20 is controlled as described above in the embodiment of the present invention. 4A shows the thermal efficiency, FIG. 4B shows the EGR rate, FIG. 4C shows the relationship between the opening of the throttle valve 32 (throttle opening) and (D) the opening of the EGR valve 46 with the torque. Yes. 4A to 4D, the common horizontal axis represents torque (load), the solid line (a) indicates that the exhaust valve 20 is controlled to the medium operating angle by the first cam, and the broken line (b) indicates the first line. When the exhaust valve 20 is controlled to a narrow operating angle by two cams, the thin broken line (c) shows a case where the intake valve 18 is controlled to a narrow operating angle by a conventional method for comparison. Further, a dashed-dotted line of Tr0 extending in the vertical axis direction represents a knock occurrence point in the example of FIG.

  As described above, in the present embodiment, the knock generation point is used as a boundary, and by switching to the second cam having a narrow operating angle on the high load region side from the knock generation point, as shown in FIG. High thermal efficiency is realized over a wide area from low load to high load.

  As shown in FIG. 4D, the opening degree of the EGR valve 46 (broken line (b)) when the exhaust valve 20 is controlled at a narrow operating angle in a region where the load is higher than the knock generation point is as follows. Compared to the opening (solid line (a)) of the EGR valve 46 set when the exhaust valve 20 is controlled to the medium operating angle in the load region, the load region where the EGR valve 46 is fully opened is on the high load side. The deviation is set so as to increase particularly in the region on the high load side.

  As shown in FIG. 4C, the throttle opening when the exhaust valve 20 is controlled to a narrow operating angle (broken line (b)) is the throttle opening when the exhaust valve 20 is controlled to a medium operating angle ( It is set smaller than the throttle opening with respect to the equal torque of the solid line (a)). In the region where the load is higher than the knock occurrence point, as shown in FIG. 4B, the exhaust valve 20 is narrower than when the exhaust valve 20 is controlled to the medium operating angle (solid line (a)). When the operating angle is controlled, the EGR rate can be increased.

  In addition, the relationship between the load and the opening degree of the EGR valve 46 and the relationship between the load and the throttle opening degree in each case of the medium working angle and the narrow working angle as described above are obtained by simulation or the like in advance. It is stored in the control device 50 as a map or the like. In actual control, each opening is set according to the load in accordance with a stored map or the like.

  FIG. 5 is a flowchart for illustrating a control routine executed by control device 50 in the embodiment of the present invention. The routine shown in FIG. 5 is a control routine that is repeatedly executed at regular intervals. In the routine of FIG. 5, it is first determined whether or not the precondition is satisfied (S102). The precondition is a condition necessary for properly performing this control, such as whether the internal combustion engine 2 is in operation or the KCS 54 is functioning normally, and is stored in advance. If the establishment of the precondition is not recognized in step S102, the current process ends.

  When the establishment of the precondition is recognized, the current load is detected (S104). The load torque is obtained according to, for example, the engine speed, ignition timing, and the like. Various methods for calculating the load torque are known, and a detailed description thereof is omitted here.

  Next, it is determined whether or not the occurrence of knocking is currently recognized (S106). The occurrence of knocking is detected by, for example, the output of a knocking sensor included in the KCS 54.

  If the occurrence of knocking is not recognized, the cam of the VVT 22 is set to the first cam, and the exhaust valve 20 is controlled to the medium operating angle (S108). Thereafter, the opening degree of the EGR valve 46 is set to an opening degree corresponding to the load when the exhaust valve 20 is controlled to the medium operating angle (S110). Further, the opening degree of the throttle valve 32 is set to an opening degree corresponding to the load when the medium operating angle is controlled (S112).

  On the other hand, if the occurrence of knocking is recognized in step S106, then the cam of VVT 22 is set to the second cam, and the exhaust valve 20 is set to a state controlled with a narrow operating angle (S114). Thereafter, the opening degree of the EGR valve 46 is set to an opening degree corresponding to the load when the exhaust valve 20 is controlled to a narrow working angle (S116). Further, the opening degree of the throttle valve 32 is set to an opening degree corresponding to the load when the exhaust valve 20 is controlled to a narrow operating angle (S118).

  Next, the current load is detected again (S120). Next, it is determined whether or not the load detected in step S120 is larger than the load at the knocking occurrence point, that is, the load detected in step S104 (S122). If the current load is larger than the load at the knock occurrence point, the current process ends as it is.

  On the other hand, if it is not determined in step S122 that the current load is greater than the load at the knock occurrence point, the process proceeds to step S108. Thereafter, the cam of the VVT 22 is set as the first cam (S108), and the opening degree of the EGR valve 46 and the opening degree of the throttle valve 32 are set accordingly (S110, S112). Thereafter, the current process ends.

  As described above, in the present embodiment, the introduction of the internal EGR due to the exhaust interference can be promoted by controlling the exhaust valve 20 to the medium operating angle in the region where the load is lower than the knock occurrence point. Further, when compared with equal load, the throttle opening is set to be larger than that in the narrow working angle mode. Therefore, pump loss can be reduced. Therefore, high thermal efficiency can be ensured in this low load region.

  On the other hand, the exhaust valve 20 is controlled at a narrow operating angle in a region where the load is higher than the knock occurrence point. Accordingly, exhaust interference is suppressed and the air amount potential can be increased. In addition, the throttle opening is reduced to ensure a high intake negative pressure. In addition, the EGR gas temperature can be reduced due to the high expansion ratio. Thereby, a large amount of EGR gas (cooled EGR) can be introduced, knocking can be improved, and thermal efficiency can be increased.

  In the above embodiment, for example, the process of step S106 is executed, thereby realizing the means for detecting or predicting the occurrence of knocking according to the present invention, and the process of step S108 is executed. Means for controlling the operating angle by one cam is realized, and means for controlling the operating angle by the second cam is realized by executing the processing of step S114. Further, in the present embodiment, means for setting the opening degree of the throttle valve of the present invention is realized by executing the processing of step S112 or S118.

  In the above embodiment, the case where the occurrence of knocking is detected and the exhaust valve 20 is controlled in the narrow working angle mode in the region where the load is higher than the load at the knocking occurrence point has been described. However, in the present invention, switching between the first cam and the second cam is not limited to this. For example, the load at the knock occurrence point where knocking is expected to occur when the exhaust valve 20 is controlled to the medium operating angle may be specified in advance by simulation or the like and stored in the control device 50. In this case, when the load calculated during operation of the internal combustion engine 2 is larger than the load at the knock occurrence point, the exhaust valve 20 can be controlled to a narrow operating angle. Thus, by determining whether or not the current load is higher than the load at the knock occurrence point, the “means for detecting or predicting the occurrence of knocking” of the present invention is realized.

  Further, switching between the first cam and the second cam is not limited to that according to the load. For example, other parameters such as required torque may be used. Also in this case, the parameter value corresponding to the knock occurrence point is specified (estimated) in advance, and the detected value of the parameter during operation of the internal combustion engine 2 is compared with the value corresponding to the knock occurrence point, What is necessary is just to determine whether it is a knock generation | occurrence | production area | region and to switch a 1st cam and a 2nd cam.

  In these cases, the load and the required torque corresponding to the knock occurrence point are not limited to those obtained in advance by simulation or the like and used as fixed values stored in the control device 50. For example, when knocking is detected by the KCS 54, the load corresponding to the knock occurrence point, the required torque, and the like can be corrected based on the load, the required torque, and the like when the knocking is detected. Thereby, switching between the first cam and the second cam can be performed more appropriately.

  Further, in the routine of FIG. 5 of the present embodiment, knocking is detected by the KCS 54 in step S106, and after the mode is set to the narrow working angle mode in step S114, the current load becomes equal to or lower than the load at the knocking point in step S122. In the case where it is confirmed that the process proceeds to step S108 and the process of switching to the medium working angle mode (S108 to S112) has been described. However, in the present invention, for example, when the occurrence of knocking is detected, the current processing may be terminated as it is after the processing of steps S114 to S118 is executed as the narrow working angle mode. Alternatively, in the present invention, for example, when it is recognized in step S120 that the load is larger than the load at the knock occurrence point, this routine is not immediately terminated, and the routine returns to step S114, where the narrow working angle mode is set. (S114 to S118) may be maintained.

  In the present embodiment, the case where the present invention is applied to the 4-cylinder spark ignition internal combustion engine 2 has been described. However, the present invention is not limited to this number of cylinders. The present invention can be applied to internal combustion engines having other numbers of cylinders as long as exhaust interference occurs between the cylinders. Also in this case, the second cam having a narrow working angle is zero or negligible in the period in which the opening period of the exhaust valve of one cylinder overlaps the opening period of the exhaust valve of another cylinder (that is, By using a cam having a narrow operating angle (which is smaller than a predetermined period including zero), exhaust interference in a region where knocking occurs can be suppressed.

  Furthermore, the present invention can be applied to an internal combustion engine provided with a plurality of exhaust manifolds. In this case, for example, the VVT only needs to control the exhaust valves of the cylinders belonging to the cylinder group to the same valve operating characteristic for each cylinder group connected to the common exhaust manifold. That is, the VVT includes a first cam and a second cam for each exhaust valve of a cylinder belonging to a certain cylinder group, and controls the exhaust valve by switching between the first cam and the second cam. . The second cam having a narrow operating angle has an opening period of an exhaust valve of any cylinder and an opening period of an exhaust valve with another cylinder belonging to the cylinder group in the same cylinder group. The exhaust valve may be opened and closed at a working angle where the overlapping period is zero or very small (that is, smaller than a predetermined period including zero).

  Further, in the above embodiment, when the number of each element, number, quantity, range, etc. is mentioned, the number mentioned unless it is clearly specified or the number is clearly specified in principle. However, the present invention is not limited to this. In addition, the structures, steps, and the like described in the present embodiment are not necessarily essential to the present invention unless otherwise specified or clearly specified in principle.

2 Internal combustion engine 10 Cylinder 12 Spark plug 14 Intake port 16 Exhaust port 18 Intake valve 20 Exhaust valve 22 Two-stage variable valve mechanism (VVT)
24 Fuel Injection Valve 26 Intake Manifold 28 Surge Tank 30 Intake Pipe 32 Throttle Valve 36 Exhaust Manifold 38 Catalyst 40 EGR Device 42 EGR Pipe 44 EGR Cooler 46 EGR Valve 50 Control Device 52 Ne Sensor 54 KCS

Claims (3)

A part of the exhaust gas of the internal combustion engine is applied as an EGR gas to a multi-cylinder internal combustion engine having an EGR device for recirculation to the intake system of the internal combustion engine,
A variable valve mechanism that has a first cam and a second cam corresponding to each exhaust valve of each cylinder, and controls the valve operating characteristics of the exhaust valve;
Means for detecting or predicting the occurrence of knocking in the internal combustion engine;
Means for controlling a working angle of the exhaust valve to a working angle of the first cam when occurrence of the knocking is not detected or predicted;
Means for controlling the exhaust valve to an operating angle by the second cam when occurrence of the knocking is detected or predicted;
With
The first cam is a cam that opens the exhaust valve on the advance side with respect to the expansion bottom dead center and closes the exhaust valve on the delay side with respect to the exhaust top dead center,
Said second cam, a control apparatus for an internal combustion engine, wherein the exhaust valve, a cam which Ru is closed at the exhaust top dead center is opened by the expansion bottom dead center.   The means for detecting or predicting the occurrence of knocking predicts the occurrence of knocking when the load on the internal combustion engine is greater than the load on the internal combustion engine at the knocking occurrence point where the occurrence of knocking is estimated. The control device for an internal combustion engine according to claim 1. When the exhaust valve is controlled by the second cam, the opening degree of the throttle valve of the internal combustion engine set for a certain load is set. When the exhaust valve is controlled by the first cam, 3. The control apparatus for an internal combustion engine according to claim 1, further comprising means for setting an opening smaller than an opening of the throttle valve set for a certain load.

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