JP2010001750A - Control device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a control device for an internal combustion engine capable of suppressing the defective changeover of a valve stop mechanism caused when the valve stop mechanism and a variable gear train which commonly use a hydraulic pressure supply system are driven simultaneously. <P>SOLUTION: This control device comprises the turbo side valve stop mechanism 54A which changes over a turbo side exhaust valve 50A to the opened/closed state or the closed state and the bypass side valve stop mechanism 54B which changes over a bypass side exhaust valve 50B to the opened/closed state or the closed state. The variable valve train 100, the turbo side valve stop mechanism 54A, and the bypass side valve stop mechanism 54B commonly use the hydraulic pressure supply system. The control device 200 stops the driving of the variable valve train 100 when the request of changeover of the valve operating state to the valve stop mechanism and the request of change of the valve characteristics to the variable valve train 100 are made simultaneously. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an internal combustion engine including a hydraulically driven variable valve mechanism and a valve stop mechanism that share a hydraulic pressure supply system.

Conventionally, as such a control device for an internal combustion engine, there are those described in Patent Document 1 and Patent Document 2, for example.
The internal combustion engine described in Patent Document 1 is provided with a first exhaust port and a second exhaust port that are independent of each other in one cylinder. A turbo-side exhaust passage that guides exhaust exhausted from the first exhaust port to the turbine upstream side of the turbocharger, and a bypass-side exhaust passage that guides exhaust exhausted from the second exhaust port to the turbine downstream side of the turbocharger. Is provided. Further, the bypass side exhaust valve that opens and closes the second exhaust port is always opened and closed, while the turbo side exhaust valve that opens and closes the first exhaust port is in either the open or closed state. Switchable to.

  When the engine temperature is low, the valve operating state of the turbo exhaust valve is controlled so that the closed state of the turbo exhaust valve is maintained. In the internal combustion engine described in Patent Document 1 in which such control is performed, all of the exhaust discharged from the cylinder is introduced into the bypass side exhaust passage without passing through the turbocharger when the engine is at a low temperature. It is possible to avoid a decrease in exhaust temperature due to passing through the turbocharger. Therefore, it is possible to quickly raise the temperature of the exhaust gas purification catalyst provided on the downstream side of the turbine.

  On the other hand, the internal combustion engine described in Patent Document 2 is also provided with a first exhaust port and a second exhaust port that are independent of each other in one cylinder, and the exhaust discharged from the first exhaust port is supplied to the turbocharger. A turbo-side exhaust passage that leads to the upstream side of the turbine and a bypass-side exhaust passage that guides the exhaust discharged from the second exhaust port to the turbine downstream side of the turbocharger are provided. The turbo exhaust valve that opens and closes the first exhaust port is always opened and closed, while the bypass exhaust valve that opens and closes the second exhaust port is in either the open or closed state. Switchable to.

In the control device described in Patent Document 2, the valve operating state of the bypass side exhaust valve is controlled so that the bypass side exhaust valve is maintained in the closed state when the engine is under a low load. In the internal combustion engine described in Patent Document 2 in which such control is performed, all the exhaust discharged from the cylinder is introduced into the turbo-side exhaust passage when the engine is under low load. A supply pressure can be suitably secured.
Special Table 2002-520535 gazette (FIG. 2 etc.) Japanese Unexamined Patent Publication No. 63-55326

  As is well known, an internal combustion engine may be provided with a hydraulically driven variable valve mechanism that changes the valve characteristics of an intake valve and an exhaust valve. In such an internal combustion engine, the valve characteristics are changed. As a result, the engine operating state is optimized.

  Here, the switching of the valve operation state as described above is performed by a mechanism capable of stopping the valve opening / closing operation and maintaining the valve closed state, that is, a so-called valve stop mechanism. When the hydraulic drive system is used and the hydraulic supply system is shared with the variable valve mechanism, the following inconvenience may occur.

  In other words, when the request for switching the valve operating state for the valve stop mechanism and the request for changing the valve characteristics for the variable valve mechanism overlap and a situation occurs in which both mechanisms are driven simultaneously, the hydraulic pressure supplied to the variable valve mechanism is reduced. Accordingly, the hydraulic pressure supplied to the valve stop mechanism decreases, and the valve stop mechanism may cause a switching failure of the valve operation state.

  The present invention has been made in view of such circumstances, and an object of the present invention is to suppress the switching failure of the valve stop mechanism due to the simultaneous drive of the valve stop mechanism and the variable valve mechanism sharing the hydraulic pressure supply system. An object of the present invention is to provide a control device for an internal combustion engine.

In the following, means for achieving the above object and its effects are described.
According to a first aspect of the present invention, there is provided a hydraulically driven variable valve mechanism for changing a valve characteristic of at least one of an intake valve and an exhaust valve, and a first exhaust port provided independently for each cylinder. And a second exhaust port, a turbo-side exhaust passage that guides exhaust discharged from the first exhaust port to the upstream side of the turbine of the turbocharger, and exhaust discharged from the second exhaust port to the downstream side of the turbine A mechanism for switching a valve operation state between an open / close state and a closed state for at least one of a bypass-side exhaust passage and an exhaust valve provided in each of the first exhaust port and the second exhaust port. It is equipped with a variable valve mechanism and a hydraulically driven valve stop mechanism that shares a hydraulic pressure supply system, and the variable valve mechanism and the valve stop mechanism are driven by an engine. A control device for an internal combustion engine that controls based on the state, and when the request for switching the valve operating state to the valve stop mechanism and the request for changing the valve characteristic to the variable valve mechanism overlap, the driving of the variable valve mechanism The gist is to limit the above.

  In the same configuration, when the valve operating state of the exhaust valve provided in the first exhaust port is switched by the valve stop mechanism, it becomes possible to stop the introduction of exhaust into the turbo-side exhaust passage and exhaust from the cylinder All of the exhausted air can be introduced into the bypass side exhaust passage. Therefore, it is possible to avoid a decrease in the temperature of the exhaust due to passing through the turbocharger, and it is possible to increase the temperature of the catalyst early. Further, when the valve operating state of the exhaust valve provided in the second exhaust port is switched by the valve stop mechanism, the exhaust introduction into the bypass side exhaust passage can be stopped, and the exhaust gas discharged from the cylinder can be stopped. All can be introduced into the turbo exhaust passage. As a result, the supercharging pressure can be suitably secured. Further, the engine operating state is optimized by changing the valve characteristic of at least one of the intake valve and the exhaust valve by the variable valve mechanism.

  Here, in the same configuration, when the request for switching the valve operating state for the valve stop mechanism and the request for changing the valve characteristic for the variable valve mechanism overlap, the driving of the variable valve mechanism is limited. For this reason, while such a drive restriction is being performed, it is possible to suppress a decrease in hydraulic pressure associated with the drive of the variable valve mechanism as compared with the case where the drive restriction is not performed. Only the hydraulic pressure supplied to the valve stop mechanism can be increased. Therefore, while the drive of the variable valve mechanism is restricted, the valve operation state can be appropriately switched by the valve stop mechanism. As described above, according to this configuration, it is possible to suppress the switching failure of the valve stop mechanism due to the simultaneous drive of the valve stop mechanism and the variable valve mechanism that share the hydraulic pressure supply system.

  According to a second aspect of the present invention, in the control device for an internal combustion engine according to the first aspect, it is determined whether or not the switching of the valve operating state by the valve stop mechanism is completed, and it is determined that the switching is completed. The gist of this is to remove the restriction on the drive of the variable valve mechanism.

  According to this configuration, when it is determined that the switching of the valve operation state by the valve stop mechanism has been completed, that is, the decrease in hydraulic pressure associated with the drive of the valve stop mechanism is eliminated, and sufficient hydraulic pressure is applied to the variable valve mechanism. When it becomes possible to supply, the drive restriction on the variable valve mechanism is released. Therefore, according to this configuration, it is possible to appropriately set a limit period for driving the variable valve mechanism.

  The invention according to claim 3 is the gist of the control device for the internal combustion engine according to claim 1 or 2, wherein when the drive of the variable valve mechanism is limited, the drive of the variable valve mechanism is stopped. And

  According to this configuration, when the drive of the variable valve mechanism is limited, the drive itself is stopped. As a result, the hydraulic pressure is not lowered due to the driving of the variable valve mechanism, and the hydraulic pressure can be sufficiently supplied to the valve stop mechanism.

  According to a fourth aspect of the present invention, in the control device for an internal combustion engine according to the first or second aspect, when the drive of the variable valve mechanism is limited, the variable motion is compared with when only the change request is present. The gist is to reduce the driving speed of the valve mechanism.

  According to this configuration, when the drive of the variable valve mechanism is limited, the drive speed is reduced. For this reason, the amount of decrease in hydraulic pressure accompanying the drive of the variable valve mechanism is reduced, and the hydraulic pressure supplied to the valve stop mechanism can be increased accordingly.

  According to a fifth aspect of the present invention, in the control device for an internal combustion engine according to the second aspect, the change in the valve operating state by the valve stop mechanism is caused by the change in the pressure of the exhaust system caused by the switching of the valve operating state. The gist of the determination is based on the above.

  When the valve operating state of at least one of the exhaust valves provided in the first exhaust port and the second exhaust port is switched to an open / close state or a closed state, the flow of exhaust gas in the exhaust system before and after the switching is performed. Since the aspect changes greatly, a pressure change occurs in the exhaust system. Therefore, in this configuration, whether or not the switching of the valve operating state by the valve stop mechanism is determined based on the pressure change of the exhaust system that occurs due to the switching of the valve operating state, and whether the switching of the valve operating state is completed. It becomes possible to appropriately determine whether or not.

  According to a sixth aspect of the present invention, in the control apparatus for an internal combustion engine according to the fifth aspect, a pressure sensor is provided in at least one of the turbo side exhaust passage and the bypass side exhaust passage, and the detected value of the pressure sensor is used. The gist is to determine the completion of switching of the valve operating state based on the above.

  The pressure in the turbo side exhaust passage is determined by an exhaust valve (hereinafter referred to as a turbo side exhaust valve) provided upstream of the turbo side exhaust passage or an exhaust valve (hereinafter referred to as bypass side exhaust valve) provided upstream of the bypass side exhaust passage. It changes as follows according to the switching of the valve operation state.

  First, when the turbo-side exhaust valve is switched from the open / close operation state to the valve-closed state, the exhaust in the turbo-side exhaust passage is stopped, so the pressure in the turbo-side exhaust passage decreases. Further, when the turbo-side exhaust valve is switched from the closed state to the open / closed operation state, the exhaust in the turbo-side exhaust passage that has been stopped until then is started, so the pressure in the turbo-side exhaust passage becomes high. Further, when the bypass side exhaust valve is switched from the open / close operation state to the valve closed state, the exhaust gas that has been exhausted to the bypass side exhaust passage until then is exhausted to the turbo side exhaust passage. The pressure increases. In addition, when the bypass side exhaust valve is switched from the closed state to the open / close operation state, a part of the exhaust that has been exhausted to the turbo side exhaust passage until then is exhausted to the bypass side exhaust passage. The pressure in the exhaust passage is lowered.

  In this way, the pressure in the turbo side exhaust passage changes with the switching of the valve operating state of the turbo side exhaust valve and bypass side exhaust valve, so the switching of the valve operating state of the turbo side exhaust valve and bypass side exhaust valve is completed. Can be determined based on the pressure change in the turbo exhaust passage.

Similarly, the pressure in the bypass side exhaust passage also changes as follows in accordance with the switching of the valve operating state of the turbo side exhaust valve and the bypass side exhaust valve.
First, when the bypass-side exhaust valve is switched from the open / close operation state to the valve-closed state, the exhaust in the bypass-side exhaust passage is stopped, so the pressure in the bypass-side exhaust passage decreases. Further, when the bypass-side exhaust valve is switched from the closed state to the open / closed operation state, the exhaust in the bypass-side exhaust passage that has been stopped until then is started, so the pressure in the bypass-side exhaust passage increases. Further, when the turbo side exhaust valve is switched from the open / close operation state to the valve closed state, the exhaust gas that has been discharged to the turbo side exhaust passage until then is discharged to the bypass side exhaust passage. The pressure increases. In addition, when the turbo side exhaust valve is switched from the closed state to the open / close operation state, a part of the exhaust that has been discharged to the bypass side exhaust passage until then is discharged to the turbo side exhaust passage. The pressure in the exhaust passage is lowered.

  In this way, the pressure in the bypass side exhaust passage changes with the switching of the valve operating state of the turbo side exhaust valve and bypass side exhaust valve, so the switching of the valve operating state of the turbo side exhaust valve and bypass side exhaust valve is completed. Can also be determined based on a pressure change in the bypass side exhaust passage.

  Therefore, in this configuration, a pressure sensor is provided in at least one of the turbo-side exhaust passage and the bypass-side exhaust passage, and the completion of switching of the valve operation state is determined based on the detection value of the pressure sensor. According to the configuration, it is possible to reliably determine completion of switching of the valve operation state by the valve stop mechanism.

  The invention according to claim 7 is the control apparatus for an internal combustion engine according to any one of claims 1 to 6, wherein the valve stop mechanism has a pin that is hydraulically inserted and removed from the hole, The gist thereof is a mechanism that switches the valve operating state by inserting and removing the pin from the hole.

  In the case of a valve stop mechanism that switches the valve operating state by hydraulically inserting and removing the pin from the hole, if the hydraulic pressure is insufficient during the switching operation, the pin will not be sufficiently inserted into and removed from the hole, and the hole or pin will wear. There is a risk that. In this regard, according to the same configuration, it is possible to appropriately ensure the hydraulic pressure during the switching operation of the valve stop mechanism, and thus it is possible to suppress wear and the like of such holes and pins.

Hereinafter, an embodiment of a control device for an internal combustion engine according to the present invention will be described with reference to FIGS.
FIG. 1 shows the structure of an intake system and an exhaust system of an engine 1 to which a control device according to the present embodiment is applied.

  The engine 1 is provided with a plurality of cylinders 2, and the cylinder head 3 is provided with a first intake port 4A, a second intake port 4B, a first exhaust port 5A, and a second exhaust port 5B for each cylinder 2. It has been.

  One end of each of the first intake port 4 </ b> A and the second intake port 4 </ b> B is opened to the combustion chamber side of the engine 1, and the other end is joined in the cylinder head 3. The cylinder head 3 is provided with an intake valve 30 for opening and closing the first intake port 4A and the second intake port 4B. An intake passage 4 is connected to a junction of the first intake port 4A and the second intake port 4B provided corresponding to each cylinder 2. The intake passage 4 is provided with a throttle valve 6 that regulates the amount of intake air. A compressor 21 of a turbocharger 20 that supercharges intake air is connected to the upstream side of the throttle valve 6.

  One end of each of the first exhaust port 5 </ b> A and the second exhaust port 5 </ b> B is opened to the combustion chamber side of the engine 1, and the other end is opened toward the outside of the cylinder head 3. Thus, the first exhaust port 5A and the second exhaust port 5B are provided in the cylinder head 3 independently of each other. The cylinder head 3 is provided with a turbo exhaust valve 50A that opens and closes the first exhaust port 5A and a bypass exhaust valve 50B that opens and closes the second exhaust port 5B.

  The first exhaust port 5A provided for each cylinder 2 and the turbine 22 of the turbocharger 20 are connected by a turbo-side exhaust passage 7A. Through the turbo-side exhaust passage 7A, the exhaust discharged from each first exhaust port 5A is introduced into the turbocharger 20 and guided upstream of the turbine 22, and the exhaust is supplied to the turbocharger 20. An exhaust passage 8 is connected to an outlet side (downstream side of exhaust) of the turbine 22, and a catalyst 9 for purifying exhaust components is provided in the middle of the exhaust passage 8.

  The second exhaust port 5B provided for each cylinder 2 and the exhaust passage 8 are connected by a bypass side exhaust passage 7B. By this bypass side exhaust passage 7B, the exhaust discharged from each second exhaust port 5B is guided to the downstream side of the turbine 22, whereby the exhaust discharged from each second exhaust port 5B passes through the turbocharger 20. Without being introduced into the catalyst 9.

  The turbo-side exhaust passage 7A and the exhaust passage 8 are connected by a communication pipe 60, and a waste gate valve (hereinafter referred to as WGV) 61 whose opening degree can be adjusted is provided in the middle of the communication pipe 60. It has been. By adjusting the amount of exhaust gas supplied to the turbocharger 20 through adjustment of the opening degree of the WGV 61, an excessive increase in the supercharging pressure is suppressed.

  FIG. 2 shows a schematic diagram of a cross section of the engine 1. As shown in FIG. 2, the cylinder head 3 is provided with a fuel injection valve 10, and an amount of fuel corresponding to the intake air amount of the engine 1 is directly injected from the fuel injection valve 10 into the cylinder 2. Is done. As a result, an air-fuel mixture consisting of air and fuel is formed in the combustion chamber 11 of each cylinder in the engine 1, and the engine output is obtained by igniting the air-fuel mixture by the spark plug 12.

  Next, the drive structure of the intake valve 30 and the turbo exhaust valve 50A will be described. Since the drive structure of the bypass side exhaust valve 50B is the same as that of the turbo side exhaust valve 50A, the drive structure of the turbo side exhaust valve 50A will be basically described below.

  The intake valve 30 is opened and closed as the intake camshaft 31 rotates. More specifically, the intake valve 30 is urged in the valve closing direction by an intake side valve spring 32, and a roller 33 </ b> A is provided between the intake cam 31 </ b> A provided on the intake camshaft 31 and the intake valve 30. An intake side rocker arm 33 is provided. When the rotating intake cam 31A presses the roller 33A, the intake side rocker arm 33 swings around the contact point with the lash adjuster 35 that supports one end of the intake side rocker arm 33, and resists the reaction force of the intake side valve spring 32. Then, the intake valve 30 is pressed. The intake valve 30 is opened and closed by the pressure of the intake valve 30 by the intake side rocker arm 33 and the reaction force of the intake side valve spring 32.

  The engine 1 is provided with a hydraulically driven variable valve mechanism 100 that continuously changes the valve characteristics of the intake valve 30. The variable valve mechanism 100 is a mechanism that changes the relative rotational phase of the intake camshaft 31 with respect to the crankshaft of the engine 1. Then, the actual value VT of the valve timing of the intake valve 30 is changed to the target value VTp set based on the engine operating state through the driving of the variable valve mechanism 100, so that the engine operating state is optimized. Improvements in engine output and exhaust purification performance can be achieved.

  FIG. 3 schematically shows the structure of the variable valve mechanism 100. As shown in FIG. 3, the variable valve mechanism 100 includes a substantially annular housing 103 and a rotor 101 housed therein. The rotor 101 is connected to an intake camshaft 31 that opens and closes the intake valve 30, and the housing 103 is connected to a cam pulley 105 that rotates in synchronization with the crankshaft of the engine 1 so as to be integrally rotatable.

  Inside the housing 103, a plurality of advance pressure chambers 106 and retard pressure chambers 107 are formed which are partitioned by the inner peripheral surface of the housing 103 and the vanes 102 provided in the rotor 101. The numbers of the advance pressure chambers 106 and the retard pressure chambers 107 can be changed as appropriate.

  Each of the advance pressure chamber 106 and the retard pressure chamber 107 is connected to the hydraulic control valve 120 via an appropriate oil passage. The hydraulic control valve 120 includes a sleeve 121 in which various ports are formed, a spool 122 that is a valve body housed in the sleeve 121 so as to be reciprocally movable, a solenoid 123 for reciprocating the spool 122, a spring 124, and the like. It has.

  The sleeve 121 includes an advance port 125 connected to the advance pressure chamber 106, a retard port 126 connected to the retard pressure chamber 107, a pump port 127 connected to the oil pump 150, and an oil pan 160. Drain ports 128 and 129 connected to each other are formed. The position of the valve body provided in the spool 122 changes to supply the hydraulic pressure to the advance pressure chamber 106, supply the hydraulic pressure to the retard pressure chamber 107, the advance pressure chamber 106, and the retard pressure chamber 107. Each hydraulic pressure is switched. The position of the spool 122 is determined by the duty ratio of the drive voltage signal applied to the solenoid 123.

  For example, when the duty ratio is in the range of “0% ≦ duty ratio <50%”, the pump port 127 and the retard port 126 are communicated with each other through the movement of the spool 122, and the drain port 128 and the advance port are used. The port 125 is communicated. As a result, hydraulic pressure is supplied to the retard pressure chamber 107, the rotor 101 is rotated to the retard side, and the valve timing is changed to the retard side. When the duty ratio is in the range of “50% <duty ratio ≦ 100%”, the pump port 127 and the advance port 125 are communicated with each other through the movement of the spool 122, and the drain port 128 and the retard port are used. Port 126 is communicated. As a result, hydraulic pressure is supplied to the advance pressure chamber 106, the rotor 101 is rotated to the advance side, and the valve timing is changed to the advance side. When the duty ratio is a value in the vicinity of 50%, the position of the spool 122 is set to a neutral position in which both the advance port 125 and the retard port 126 are closed, so that the advance pressure chamber 106 is closed. In addition, the hydraulic pressure of the retard pressure chamber 107 is maintained, and basically, the valve timing is maintained in the current state.

  The turbo-side exhaust valve 50 </ b> A and the bypass-side exhaust valve 50 </ b> B are opened and closed as the exhaust camshaft 51 rotates. The turbo exhaust valve 50A is urged in the valve closing direction by an exhaust valve spring 52, and an exhaust cam 51A is provided between the exhaust cam 51A provided on the exhaust cam shaft 51 and the turbo exhaust valve 50A. An exhaust-side rocker arm 53 having a roller 53A that is in contact with is provided. The rotating exhaust cam 51A presses the exhaust side rocker arm 53 via the roller 53A, so that the exhaust side rocker arm 53 swings around a contact point with the lash adjuster 55 that supports one end thereof, and the exhaust side valve spring. The turbo exhaust valve 50A is pressed against the reaction force of 52. The turbo side exhaust valve 50A is opened and closed by the pressure of the turbo side exhaust valve 50A by the exhaust side rocker arm 53 and the reaction force of the exhaust side valve spring 52.

  The exhaust-side rocker arm 53 is provided with a turbo-side valve stop mechanism 54A that switches the valve operating state of the turbo-side exhaust valve 50A between an open / close state and a valve-closed state. The turbo-side valve stop mechanism 54A is a mechanism capable of stopping the operation of the open / close operation of the turbo-side exhaust valve 50A caused by the exhaust cam 51A pressing the exhaust-side rocker arm 53.

  FIG. 4 schematically shows a partial cross section of the structure of the turbo valve stop mechanism 54A. As shown in FIG. 4, on the exhaust side rocker arm 53, on the inner side of the body 53D with which the turbo side exhaust valve 50A and the lash adjuster 55 abut, there is a swinging portion 53C on which the roller 53A is rotatably supported. Is provided.

  A torsion bar 53E is fixed to one end of the swinging portion 53C, and both ends of the torsion bar 53E are fixed to the body 53D of the exhaust side rocker arm 53. The swing part 53C is swingable with respect to the body 53D around the axis of the torsion bar 53E.

A hole-shaped first hydraulic chamber 53F is provided at the other end of the swinging portion 53C. In the first hydraulic chamber 53F, a pin 53P having a diameter substantially the same as the inner diameter is disposed.
In the body 53D, a second hydraulic chamber 53H having a hole shape substantially the same diameter as the first hydraulic chamber 53F is formed at a portion facing the first hydraulic chamber 53F. The depth of the second hydraulic chamber 53H is shorter than the length of the pin 53P.

  The second hydraulic chamber 53H is connected to the control valve 310 via the second hydraulic passage 300H. The first hydraulic chamber 53F is connected to the control valve 310 via an oil passage 300A formed in the swing portion 53C and the torsion bar 53E, and a first hydraulic passage 300F connected to the oil passage 300A. It is connected. The control valve 310 is connected to the oil pump 150 via a hydraulic passage 300C.

  As shown in FIG. 4, when the turbo-side valve stop mechanism 54A is not in operation, the drive control of the control valve 310 is performed so that the hydraulic pressure is supplied to the first hydraulic chamber 53F, whereby the pin 53P is connected to the second hydraulic chamber 53H. And the first hydraulic chamber 53F is inserted. In this case, when the swinging of the swinging portion 53C with respect to the body 53D is restricted and the roller 53A is pressed by the exhaust cam 51A, the exhaust-side rocker arm 53 swings based on that and the turbo-side exhaust valve 50A opens and closes. Be operated.

  On the other hand, as shown in FIG. 5, when the turbo-side valve stop mechanism 54A is operated, the drive control of the control valve 310 is performed so that the hydraulic pressure is supplied to the second hydraulic chamber 53H, whereby the pin 53P is connected to the second hydraulic chamber. It is separated from 53H and is inserted into only the first hydraulic chamber 53F. In this case, the swing part 53C can swing with respect to the body 53D. Therefore, when the roller 53A is pressed by the exhaust cam 51A, the roller 53A moves relative to the exhaust-side rocker arm 53 (body 53), so that it is in an idling state. Therefore, the swinging of the exhaust side rocker arm 53 is stopped, whereby the opening and closing operation of the turbo side exhaust valve 50A accompanying the rotation of the exhaust cam 51A is stopped, and the turbo side exhaust valve 50A is held in the closed state.

  The exhaust-side rocker arm 53 that opens and closes the bypass-side exhaust valve 50B is also provided with a bypass-side valve stop mechanism 54B having the same structure as the turbo-side valve stop mechanism 54A. The bypass-side valve stop mechanism 54B Also, the operating state is switched by a control valve 310 similar to the control valve 310 corresponding to the turbo-side valve stop mechanism 54A described above. When the bypass side valve stop mechanism 54B is not operated, the bypass side exhaust valve 50B is opened and closed, and when the bypass side valve stop mechanism 54B is operated, the bypass side exhaust valve 50B is held in a closed state. Further, the oil path switching performed by the control valve 310 corresponding to the turbo side valve stop mechanism 54A and the control valve 310 corresponding to the bypass side valve stop mechanism 54B is performed based on a switching signal from the control device 200 described later. .

  FIG. 6 schematically shows a drive system for the exhaust valve in the present embodiment. As shown in FIG. 6, the rotation of the exhaust cam 51A that opens and closes the turbo-side exhaust valve 50A is transmitted to the turbo-side exhaust valve 50A via the exhaust-side rocker arm 53 including the turbo-side valve stop mechanism 54A. Similarly, the rotation of the exhaust cam 51A that opens and closes the bypass side exhaust valve 50B is transmitted to the bypass side exhaust valve 50B via the exhaust side rocker arm 53 including the bypass side valve stop mechanism 54B.

  As shown in FIG. 1, the engine 1 is provided with various sensors. For example, the accelerator position sensor 210 detects an accelerator pedal depression amount (accelerator operation amount ACCP) that is depressed by a vehicle driver. The throttle position sensor 220 detects the opening of the throttle valve 6 (throttle opening TA). Further, the air flow meter 230 detects the amount of air taken into the engine 1 (intake air amount GA). The crank position sensor 240 detects the rotation angle of the crankshaft of the engine 1, that is, the crank angle, and calculates the engine rotation speed NE based on the detection signal. Further, the coolant temperature THW of the engine 1 is detected by the water temperature sensor 250. Further, the rotational phase of the intake camshaft 31 is detected by a cam angle sensor 260 provided in the vicinity of the intake camshaft 31, and is made variable based on the detection values of the cam angle sensor 260 and the crank position sensor 240. The actual value VT of the valve timing of the intake valve 30 is calculated. Further, the pressure of the intake air supercharged by the turbocharger 20, that is, the supercharging pressure CP is detected by a supercharging pressure sensor 270 provided between the compressor 21 and the throttle valve 6. Further, the exhaust pressure sensor 280 provided in the turbo side exhaust passage 7A detects the pressure EP of the exhaust gas in the turbo side exhaust passage 7A.

  Various controls of the engine 1 are performed by the control device 200. The control device 200 includes a CPU that executes arithmetic processing related to various controls, a ROM that stores programs and data necessary for the control, a RAM that temporarily stores the arithmetic results of the CPU, and signals between the outside and the outside. The input / output port for inputting / outputting is provided. The input port is connected to signal lines of the above various sensors. The output port includes a fuel injection valve 10, a spark plug 12, a throttle valve 6, a WGV 61, a hydraulic control valve 120 that controls the drive of the variable valve mechanism 100, a control valve 310 corresponding to the turbo valve stop mechanism 54A, A drive control circuit such as a control valve 310 corresponding to the bypass side valve stop mechanism 54B is connected. And the control apparatus 200 outputs a command signal to the various drive control circuits connected to the said output port according to the engine operation state detected by various sensors. Thereby, fuel injection control, ignition timing control, intake air amount control, WGV 61 opening control, variable valve mechanism 100 drive control, turbo side valve stop mechanism 54A and bypass side valve stop mechanism 54B drive control, etc. are controlled. Implemented by apparatus 200.

  Hereinafter, an operation process of the turbo-side exhaust valve 50A and the bypass-side exhaust valve 50B, whose operation states are switched by drive control of the turbo-side valve stop mechanism 54A and the bypass-side valve stop mechanism 54B, which is performed by the control device 200, will be described.

FIG. 7 shows the procedure of the exhaust valve operation process. This process is repeatedly executed by the control device 200 at predetermined intervals.
When this process is started, first, it is determined whether or not the coolant temperature THW is equal to or lower than the warm-up completion determination value THd (S100). If the coolant temperature THW is equal to or lower than the warm-up completion determination value THd (S100: YES), it is determined that the engine 1 is in a cold state, the process of step S110 is performed, and this process is temporarily terminated. Is done.

  In step S110, the bypass side exhaust valve 50B is opened and closed by disabling the bypass side valve stop mechanism 54B, and the turbo side exhaust valve 50A is closed by operating the turbo side valve stop mechanism 54A. Retained. As a result, all the exhaust discharged from each cylinder 2 is introduced into the bypass-side exhaust passage 7B, and the temperature drop of the exhaust due to passing through the turbocharger 20 can be avoided. The temperature of the catalyst 9 can be raised quickly at that time.

  On the other hand, when the coolant temperature THW exceeds the warm-up completion determination value THd (S100: NO), it is determined that the warm-up of the engine 1 has been completed, and each process after step S120 is performed.

  First, in step S120, the switching pressure CP1 is set based on the engine rotational speed NE. The switching pressure CP1 is set as a determination value for determining whether or not the engine load is in a low load state lower than a preset specified load. That is, the intake air amount correlated with the engine load and the supercharging pressure CP have a correlation, and it can be determined that the lower the supercharging pressure CP, the smaller the intake air amount and the lower the engine load. Here, even if the supercharging pressure CP is the same, the intake air amount per unit time increases as the engine speed NE increases, and as a result, the engine load also increases. Accordingly, when determining the engine load based on the supercharging pressure CP, it is desirable to variably set the switching pressure CP1 so as to decrease as the engine speed NE increases in consideration of the influence of the engine speed on the intake air amount. Therefore, in step S120, the switching pressure CP1 is variably set based on the engine rotational speed NE so that the switching pressure CP1 decreases as the engine rotational speed NE increases. Thereby, the state determination of the engine load by the supercharging pressure CP is accurately performed.

  Next, it is determined whether or not the current supercharging pressure CP is equal to or higher than the switching pressure CP1 set in the above manner (S130). When the supercharging pressure CP is less than the switching pressure CP1 (S130: NO), it is determined that the current engine load is in a low load state equal to or less than the specified load, and the process of step S140 is performed. This process is once terminated.

  In step S140, the bypass side exhaust valve 50B is kept closed by operating the bypass side valve stop mechanism 54B, and the turbo side exhaust valve 50A is opened and closed by deactivating the turbo side valve stop mechanism 54A. Be operated. As a result, all the exhaust discharged from each cylinder 2 is introduced into the turbo-side exhaust passage 7A. Accordingly, in the process of increasing the engine load from the low load state or from the low load state, the exhaust flow rate to the turbocharger 20 is sufficiently secured, and in the process of increasing the engine load from the low load state or from the low load state. The supercharging pressure CP can be sufficiently increased. Therefore, in the process of increasing the engine load from a low load state, the demand for increasing the engine output becomes high. However, the boost pressure CP that affects the increase in the engine output can be sufficiently increased. The acceleration response from the state is improved.

  If it is determined in step S130 that the supercharging pressure CP is equal to or higher than the switching pressure CP1 (S130: YES), the current engine load is higher than the state in which it is determined to be in the low load state. As a result of the determination, the process of step S150 is performed, and this process is temporarily terminated.

  In step S150, the bypass side exhaust valve 50B is opened / closed by deactivating the bypass side valve stop mechanism 54B, and the turbo side exhaust valve 50A is also opened / closed by deactivating the turbo side valve stop mechanism 54A. Is done. As a result, when the supercharging pressure CP changes from a state below the switching pressure CP1 to a state above the switching pressure CP1, the bypass side exhaust valve 50B is closed in addition to the turbo side exhaust valve 50A that has been opened and closed until then. The valve state is switched to the open / close operation state. Thus, when the supercharging pressure CP becomes equal to or higher than the switching pressure CP1, the following effects can be obtained by switching the operating state of the bypass side exhaust valve 50B from the closed state to the open / close operation.

  That is, when the supercharging pressure CP is equal to or higher than the switching pressure CP1 and the engine load is higher than the state determined to be a low load state, the supercharging pressure CP is less than the switching pressure CP1. The exhaust flow rate has increased compared to the case. Thus, if all the exhaust gas discharged from each cylinder 2 is supplied to the turbocharger 20 when the exhaust gas flow rate is increasing, an excessive amount of exhaust gas is supplied to the turbocharger 20 in some cases. As a result, the pressure loss in the turbocharger 20 may increase and the engine output may decrease. In this regard, by performing the process of step S150, when the supercharging pressure CP is equal to or higher than the switching pressure CP1, that is, the engine load is higher than the state in which it is determined to be a low load state. When the engine is in an engine operating state in which the exhaust flow rate increases more, the operating state of the bypass side exhaust valve 50B is switched from the closed state to the open / close operation. As a result, part of the exhaust discharged from each cylinder 2 is diverted to the bypass side exhaust passage 7B, and excessive exhaust supply to the turbocharger 20 is suppressed. For this reason, an increase in pressure loss in the turbocharger 20 in an engine operating state in which the exhaust flow rate increases is suppressed, and a decrease in engine output in such an engine operating state can be suppressed.

  By the way, the turbo side valve stop mechanism 54A, the bypass side valve stop mechanism 54B, and the variable valve mechanism 100 all use the hydraulic pressure generated by the oil pump 150 as a drive source, and share the hydraulic pressure supply system. Therefore, depending on the case, there are concerns about the following inconveniences.

  That is, when a request for switching the valve operating state for the valve stop mechanism and a request for changing the valve timing for the variable valve mechanism 100 overlap, a situation occurs in which both mechanisms are driven at the same time, the variable valve mechanism 100 is supplied. The hydraulic pressure supplied to the valve stop mechanism decreases by the amount of the hydraulic pressure, and the valve stop mechanism may cause a switching failure of the valve operation state. In addition, when the switching failure of the valve stop mechanism (the turbo-side valve stop mechanism 54A or the bypass-side valve stop mechanism 54B) due to insufficient hydraulic pressure occurs, the insertion and removal of the pin 53P with respect to the second hydraulic chamber 53H becomes insufficient, and the second hydraulic pressure There is also a possibility that wear or the like may occur on the wall surface of the chamber 53H or the outer peripheral surface of the pin 53P.

Therefore, in the present embodiment, in order to suppress such switching failure, the following variable valve mechanism drive restriction process is performed.
FIG. 8 shows the procedure of the drive restriction process. This process is repeatedly executed by the control device 200.

  When this process is started, it is first determined whether or not there is a request for changing the valve timing to the variable valve mechanism 100 (S200). Here, when the target value VTp of the current valve timing is different from the target value VTp at the time of the previous execution of this processing, it is determined that there is a request for changing the valve timing. If there is no request for changing the valve timing (S200: NO), this process is temporarily terminated.

  On the other hand, when there is a request for changing the valve timing (S200: YES), whether or not there is a request for switching the valve operation state to each valve stop mechanism such as the turbo-side valve stop mechanism 54A and the bypass-side valve stop mechanism 54B. More specifically, it is determined whether or not there is a state in which a decrease in hydraulic pressure associated with driving of each valve stop mechanism occurs (S210). Here, when there is a request for switching from the non-operating state to the operating state for at least one of the turbo-side valve stop mechanism 54A and the bypass-side valve stop mechanism 54B, or when there is a request for switching from the operating state to the non-operating state. Affirmative determination is made in some cases. In other words, when there is a switching request for switching the valve operation state of the turbo-side exhaust valve 50A or the bypass-side exhaust valve 50B from the opening / closing operation state to the valve closing state, or there is a switching request for switching from the valve closing state to the opening / closing operation state. Affirmative determination is made. When there is no request for switching the valve operating state (S210: NO), this process is temporarily terminated.

  On the other hand, when there is a request for switching the valve operating state (S210: YES), it is determined whether or not the switching of the valve operating state by the valve stop mechanism has been completed (S220). Here, switching completion is determined based on the following principle.

  That is, when the valve operating state of at least one of the exhaust valves provided in the first exhaust port 5A and the second exhaust port 5B is switched to the open / close state or the closed state, before and after the switching, the exhaust system Since the flow mode of the exhaust gas greatly changes, the pressure changes in the exhaust system. In view of this, the completion of switching of the valve operating state by the valve stop mechanism is determined based on the pressure change of the exhaust system caused by switching of the valve operating state. More specifically, when the turbo-side exhaust valve 50A is switched from the open / close operation state to the valve-closed state, the exhaust of the exhaust to the turbo-side exhaust passage 7A is stopped, so the pressure in the turbo-side exhaust passage 7A decreases. To do. When the turbo-side exhaust valve 50A is switched from the closed state to the open / closed operation state, the exhaust in the turbo-side exhaust passage 7A stopped until then is started, so the pressure in the turbo-side exhaust passage 7A is Get higher.

  Further, when the bypass-side exhaust valve 50B is switched from the open / close operation state to the valve-closed state, the exhaust that has been discharged to the bypass-side exhaust passage 7B until then is discharged to the turbo-side exhaust passage 7A. The pressure in the exhaust passage 7A increases. Further, when the bypass side exhaust valve 50B is switched from the closed state to the open / close operation state, a part of the exhaust gas that has been discharged to the turbo side exhaust passage 7A until then is discharged to the bypass side exhaust passage 7B. The pressure in the turbo side exhaust passage 7A becomes low.

  Thus, the pressure in the turbo side exhaust passage 7A changes with the switching of the valve operating states of the turbo side exhaust valve 50A and the bypass side exhaust valve 50B. Therefore, in step S220, a change amount within a preset time is calculated for the pressure EP in the turbo exhaust passage 7A detected by the exhaust pressure sensor 280, and the calculated pressure change amount EPh is preset. If it is greater than or equal to the determination value α, it is determined that the switching has been completed.

  Note that the pressure EP also changes due to a change in the exhaust flow rate accompanying a change in the engine load. However, the change amount of the pressure EP per time when the exhaust valve is switched from the open / close operation state to the valve close state is sufficiently larger than the change amount of the pressure EP due to the change of the engine load. Therefore, by appropriately setting the determination value α, it is possible to suppress the occurrence of such an inconvenience that the change in the pressure EP due to the change in the engine load is erroneously determined as switching completion.

  If it is determined that the switching of the valve operating state has not been completed (S220: NO), the driving of the variable valve mechanism 100 is stopped (S230), and this process is temporarily terminated. When the drive of the variable valve mechanism 100 is restricted in this way, the hydraulic pressure associated with the drive of the variable valve mechanism 100 is reduced while the drive restriction is being performed as compared with the case where the drive restriction is not performed. The hydraulic pressure supplied to the valve stop mechanism is increased by the amount of suppression of the decrease in hydraulic pressure. Therefore, while the driving of the variable valve mechanism 100 is restricted, the valve operation state can be switched by the valve stop mechanism, and the switching failure of the valve stop mechanism can be suppressed. In particular, in step S230, since the drive restriction is performed such that the drive of the variable valve mechanism 100 is stopped, the hydraulic pressure is not reduced due to the drive of the variable valve mechanism 100, and the valve stop mechanism is Hydraulic pressure is sufficiently supplied.

  On the other hand, when it is determined that the switching of the valve operating state has been completed (S220: YES), the drive stop of the variable valve mechanism 100 is released (S240), and this process is temporarily ended. Thus, when it is determined that the switching of the valve operation state by the valve stop mechanism has been completed, that is, the decrease in the hydraulic pressure associated with the driving of the valve stop mechanism is eliminated, and sufficient hydraulic pressure is supplied to the variable valve mechanism 100. When it becomes possible to do so, the drive restriction on the variable valve mechanism 100 is released. Therefore, the time limit for driving the variable valve mechanism 100 is set appropriately.

FIG. 9 shows an example of the effect of the drive restriction process.
As shown in FIG. 9, when the valve timing target value VTp is changed at time t1, a request for changing the valve timing is made to the variable valve mechanism 100, the variable valve mechanism 100 is driven, The actual value VT of the valve timing is gradually changed toward the target value VTp. In the middle of changing the valve timing, since the hydraulic pressure is supplied to the variable valve mechanism 100, the hydraulic pressure P of the hydraulic pressure supply system decreases by the amount of the hydraulic pressure decrease PV required for driving the variable valve mechanism 100. More specifically, the first hydraulic pressure P1 is decreased by an amount corresponding to the hydraulic pressure decrease PV with respect to the initial hydraulic pressure P0 before the variable valve mechanism 100 starts to be driven.

  In the course of changing the valve timing, at least one of the turbo-side valve stop mechanism 54A and the bypass-side valve stop mechanism 54B is requested to make a switching request for switching from non-operation to operation. When a switching signal is output to the control valve 310 (time t2), the hydraulic pressure is also supplied to the valve stop mechanism to start the switching operation. Since the hydraulic pressure is supplied to the valve stop mechanism during such a switching operation, the hydraulic pressure P of the hydraulic pressure supply system decreases by the hydraulic pressure decrease PB required for the switching operation.

  Here, when the drive restriction process is not executed, that is, when the valve operation state switching request for the valve stop mechanism and the valve timing change request for the variable valve mechanism 100 overlap, the driving of the variable valve mechanism 100 is performed. When the change of the actual value VT is continued without being limited (illustrated by a two-dot chain line L1), the hydraulic pressure P greatly decreases. That is, the hydraulic pressure P, which has been reduced to the first hydraulic pressure P1 by driving the variable valve mechanism 100, further decreases by the hydraulic pressure reduction PB (shown by the two-dot chain line L2) due to the driving of the valve stop mechanism. Since it becomes the 2nd oil pressure P2, this 2nd oil pressure P2 may become lower than the oil pressure required for the action | operation of a valve stop mechanism.

  On the other hand, when the drive restriction process is executed, the variable valve mechanism 100 is driven when the valve operation state switching request for the valve stop mechanism and the valve timing change request for the variable valve mechanism 100 overlap. Stopped. As a result, the hydraulic pressure drop PB due to the drive of the valve stop mechanism is offset to some extent by the cancellation of the hydraulic pressure drop PV due to the drive stop of the variable valve mechanism 100, and the hydraulic pressure P during the switching operation of the valve stop mechanism is It becomes higher than the hydraulic pressure P2. Therefore, the occurrence of switching failure of the valve stop mechanism due to insufficient hydraulic pressure is suppressed.

  When the switching of the valve operation state is completed (time t3), the change in valve timing is resumed by releasing the drive stop of the variable valve mechanism 100, and the actual value VT of the valve timing is directed toward the target value VTp. It will be changed. After this time t3, since the decrease in the hydraulic pressure associated with the switching operation of the valve stop mechanism has been eliminated, the hydraulic pressure P becomes the first hydraulic pressure P1, and sufficient hydraulic pressure is supplied to the variable valve mechanism 100. be able to.

  FIG. 9 illustrates a case where a valve operation state change request is made during the change of the valve timing, as an example of a case where the valve operation state change request and the valve timing change request overlap. Other examples where these requests overlap are when a valve timing change request is made during the switching of the valve operation state, or when a valve timing change request and a valve operation state change request are made at the same time. However, in this case, the same effect can be obtained by executing the drive restriction process.

As described above, according to the present embodiment, the following effects can be obtained.
(1) In the engine 1 in which the hydraulic drive type valve stop mechanism such as the turbo side valve stop mechanism 54A and the bypass side valve stop mechanism 54B and the hydraulic drive type variable valve mechanism 100 share the hydraulic supply system, The control like this is done.

  That is, when the request for switching the valve operating state to the valve stop mechanism and the request for changing the valve timing to the variable valve mechanism 100 overlap, the driving of the variable valve mechanism 100 is limited. Therefore, while such a drive restriction is being performed, it is possible to suppress a decrease in hydraulic pressure associated with the driving of the variable valve mechanism 100 as compared with the case where the drive restriction is not performed, and to suppress the decrease in the hydraulic pressure. Accordingly, the hydraulic pressure supplied to the valve stop mechanism can be increased. Accordingly, the valve operation state can be appropriately switched by the valve stop mechanism while the driving of the variable valve mechanism 100 is restricted. Thus, according to the present embodiment, the valve stop by simultaneously driving the valve stop mechanism (the turbo side valve stop mechanism 54A and the bypass side valve stop mechanism 54B) and the variable valve mechanism 100 sharing the hydraulic pressure supply system. It becomes possible to suppress the switching failure of the mechanism.

  (2) It is determined whether or not the switching of the valve operating state by the valve stopping mechanism has been completed, and when it is determined that the switching of the valve operating state has been completed, that is, the decrease in hydraulic pressure associated with the driving of the valve stopping mechanism is eliminated. Then, when a sufficient hydraulic pressure can be supplied to the variable valve mechanism 100, the drive restriction on the variable valve mechanism 100 is released. Therefore, it is possible to appropriately set a limit period when limiting the driving of the variable valve mechanism 100.

  (3) When the drive of the variable valve mechanism 100 is limited, the drive of the variable valve mechanism 100 is stopped. As a result, the hydraulic pressure is not reduced as the variable valve mechanism 100 is driven, and the hydraulic pressure can be sufficiently supplied to the valve stop mechanism.

  (4) When the valve operating state of at least one of the exhaust valves respectively provided in the first exhaust port 5A and the second exhaust port 5B is switched to the open / close state or the closed state, the exhaust is performed before and after the switching. Since the flow mode of the exhaust gas in the system changes greatly, a pressure change occurs in the exhaust system. In view of this, the completion of switching of the valve operating state by the valve stop mechanism is determined based on the pressure change of the exhaust system caused by switching of the valve operating state. More specifically, the completion of such switching is determined based on the pressure EP of the exhaust gas in the turbo side exhaust passage 7A detected by the exhaust pressure sensor 280 provided in the turbo side exhaust passage 7A. Accordingly, it is possible to reliably determine whether or not the switching of the valve operation state has been completed.

  (5) The valve stop mechanism (the turbo side valve stop mechanism 54A and the bypass side valve stop mechanism 54B) is provided with a pin 53P that is hydraulically inserted and removed from the hole-shaped second hydraulic chamber 53H. The valve operating state is switched by taking the pin 53P into and out of the second hydraulic chamber 53H. Thus, in the case of a valve stop mechanism that switches the valve operating state by hydraulically inserting and removing the pin 53P from the hole-shaped second hydraulic chamber 53H, if the hydraulic pressure is insufficient during the switching operation, the pin 53P with respect to the second hydraulic chamber 53H Insertion / removal becomes insufficient, and the second hydraulic chamber 53H and the pin 53P may be worn away. In this respect, according to the present embodiment, it is possible to appropriately ensure the hydraulic pressure during the switching operation of the valve stop mechanism, and thus it is possible to suppress such wear of the second hydraulic chamber 53H and the pin 53P.

In addition, the said embodiment can also be changed and implemented as follows.
-When limiting the driving of the variable valve mechanism 100, the driving itself is stopped. In addition, when the drive of the variable valve mechanism 100 is limited, the drive speed of the variable valve mechanism 100 may be decreased as compared with when only the valve timing change request is made. In this case, by reducing the driving speed of the variable valve mechanism 100, the amount of decrease in hydraulic pressure accompanying the driving of the variable valve mechanism 100 (the above-described hydraulic pressure decrease PV) is reduced. The supplied hydraulic pressure can be increased. In implementing this modification, for example, the processing of step S230 and step S240 shown in FIG. 8 may be changed to the processing of step S330 and step S340 shown in FIG. That is, if a negative determination is made in step S220, the drive speed of the variable valve mechanism 100 is reduced so that sufficient oil pressure is secured to the valve stop mechanism (S330), and affirmative in step S220. When the determination is made, the drive speed of the variable valve mechanism 100 may be returned to the speed before the limit (S340).

  Similar to the pressure in the turbo-side exhaust passage 7A, the pressure in the bypass-side exhaust passage 7B also changes as follows according to the switching of the valve operating states of the turbo-side exhaust valve 50A and the bypass-side exhaust valve 50B.

  First, when the bypass-side exhaust valve 50B is switched from the open / close operation state to the valve-closed state, the exhaust in the bypass-side exhaust passage 7B is stopped, so the pressure in the bypass-side exhaust passage 7B decreases. Further, when the bypass-side exhaust valve 50B is switched from the closed state to the open / closed operation state, the exhaust in the bypass-side exhaust passage 7B stopped so far is started, so the pressure in the bypass-side exhaust passage 7B is Get higher. Further, when the turbo-side exhaust valve 50A is switched from the open / close operation state to the valve-closed state, the exhaust gas that has been discharged to the turbo-side exhaust passage 7A until then is discharged to the bypass-side exhaust passage 7B. The pressure in the exhaust passage 7B increases. Further, when the turbo side exhaust valve 50A is switched from the closed state to the open / close operation state, a part of the exhaust gas that has been discharged to the bypass side exhaust passage 7B until then is discharged to the turbo side exhaust passage 7A. The pressure in the bypass side exhaust passage 7B becomes low.

  As described above, the pressure in the bypass side exhaust passage 7B also changes as the valve operating states of the turbo side exhaust valve 50A and the bypass side exhaust valve 50B are switched. Therefore, instead of the pressure change in the turbo side exhaust passage 7A, the completion of the switching of the valve operation state of the turbo side exhaust valve 50A and the bypass side exhaust valve 50B is determined based on the pressure change in the bypass side exhaust passage 7B. May be. In carrying out this modification, the exhaust pressure sensor 280 is eliminated, and as shown by the two-dot chain line in FIG. 1, the exhaust pressure sensor 480 is provided in the bypass exhaust passage 7B, and the bypass exhaust passage 7B is provided. The pressure EP of the exhaust gas in the inside may be detected. Incidentally, exhaust pressure sensors are provided in both the turbo-side exhaust passage 7A and the bypass-side exhaust passage 7B. Then, the completion of switching of the valve operating state of the turbo side exhaust valve 50A is determined based on the pressure change in the turbo side exhaust passage 7A, and the completion of switching of the valve operating state of the bypass side exhaust valve 50B is determined according to the bypass side exhaust. You may make it determine based on the pressure change in the channel | path 7B. In addition, since the pressure in the exhaust passage 8 also changes depending on the switching of the valve operating state of the turbo exhaust valve 50A and the bypass exhaust valve 50B, an exhaust pressure sensor for detecting the pressure in the exhaust passage 8 is provided. Completion of switching of the valve operation state may be determined based on the detection value of the pressure sensor.

  -The switching determination of the valve operation state may be performed in another manner. For example, when the operation state of the turbo exhaust valve 50A and the bypass exhaust valve 50B is switched, the exhaust flow rate of the turbocharger 20 to the turbine 22 changes, and the supercharging pressure CP also changes. Therefore, it is also possible to perform the switching determination of the valve operation state based on the supercharging pressure CP. Further, it is determined that the switching of the valve operation state is completed when an elapsed time has passed since it is estimated that the switching has actually been completed after the switching signal is output to the control valve 310. May be. Further, a sensor or a switch for detecting the completion of switching may be provided in the valve stop mechanism.

  -Whether or not the engine temperature is in a cold state below the specified temperature is determined based on the cooling water temperature THW, but it is determined based on other parameters such as intake air temperature and oil temperature. Also good.

Although the switching pressure CP1 is variably set based on the engine speed NE, more simply, it may be fixed at a preset constant value.
-Whether or not the engine load is in a low load state below the specified load is determined based on the boost pressure CP. In addition, based on the intake air amount GA, the accelerator operation amount ACCP, the fuel injection amount of the fuel injection valve 10, etc., it may be determined whether or not the engine load is in a low load state below a specified load. .

  When the coolant temperature THW is equal to or lower than the warm-up completion determination value THd, the bypass-side exhaust valve 50B is opened and closed, and the turbo-side exhaust valve 50A is held in the closed state, thereby warming up earlier than ensuring the engine output. Added priority to completion. In addition, even when the cooling water temperature THW is equal to or lower than the warm-up completion determination value THd, when the supercharging pressure CP exceeds the switching pressure CP1, the turbo-side exhaust valve 50A is opened / closed so that the warm-up is completed earlier. Alternatively, priority may be given to securing the engine output.

  -As shown in previous FIG. 6, in the said embodiment, the valve stop mechanism was provided in both the turbo side exhaust valve 50A and the bypass side exhaust valve 50B. In addition, as shown in FIG. 11, only the turbo exhaust valve 50A may be provided with a valve stop mechanism so that the bypass exhaust valve 50B is always opened and closed. In this case, for example, as shown in FIG. 12, when it is determined that the coolant temperature THW is equal to or lower than the warm-up completion determination value THd and the engine 1 is in a cold state, the valve of the turbo exhaust valve 50A Set the operating state to the closed state. When it is determined that the coolant temperature THW exceeds the warm-up completion determination value THd and the warm-up of the engine 1 is complete, the valve operating state of the turbo-side exhaust valve 50A is set to the open / close operation state. May be. Even in this case, the catalyst 9 can be quickly heated.

  Further, as shown in FIG. 13, a valve stop mechanism may be provided only in the bypass side exhaust valve 50B so that the turbo side exhaust valve 50A is always opened and closed. In this case, for example, as shown in FIG. 14, when it is determined that the supercharging pressure CP is less than the switching pressure CP1 and the current engine load is in a low load state equal to or less than a specified load, bypass is performed. The side exhaust valve 50B is closed. When it is determined that the supercharging pressure CP is equal to or higher than the switching pressure CP1 and the current engine load is higher than a state where it is determined to be a low load state, the bypass side exhaust valve 50B is brought into an open / close operation state. You may do it. Also in this case, the supercharging pressure CP at the time of low load operation can be suitably secured, and an increase in pressure loss in the turbocharger 20 in an engine operation state in which the exhaust flow rate increases can be suppressed.

  Further, as shown in FIG. 14, when the coolant temperature THW is equal to or lower than the warm-up completion determination value THd and it is determined that the engine 1 is in the cold state, the bypass side exhaust valve 50B is brought into the open / close operation state. . When the coolant temperature THW exceeds the warm-up completion determination value THd and it is determined that the engine 1 has been warmed up, the bypass side exhaust valve 50B may be closed. Even in this case, the temperature of the catalyst 9 can be raised quickly when it is cold.

  The turbo-side valve stop mechanism 54A and the bypass-side valve stop mechanism 54B are mechanisms in which the exhaust valve is kept closed during its operation, and the exhaust valve is opened and closed when it is not in operation. A mechanism may be used in which the exhaust valve is opened and closed during operation, and the exhaust valve is held closed when the exhaust valve is not operated.

  The operation mode of the turbo-side exhaust valve 50A and the bypass-side exhaust valve 50B is not limited to the above-described turbo-side valve stop mechanism 54A and bypass-side valve stop mechanism 54B, and is changed to either the open / close operation state or the valve-close state with other configurations. A mechanism that can be switched may be used.

  In the above embodiment, the variable valve mechanism 100 is provided only in the intake valve 30, but the variable valve mechanism that changes the valve characteristics of each exhaust valve such as the turbo-side exhaust valve 50A and the bypass-side exhaust valve 50B. May be provided. For example, as shown in FIG. 15, a mechanism similar to the variable valve mechanism 100 may be provided on the exhaust camshaft 51. Further, the variable valve mechanism 100 may be provided only in the exhaust valve.

-Not only the said variable valve mechanism 100 but the mechanism which changes valve timing with another structure, and the mechanism which makes variable the maximum lift amount of a valve may be sufficient.
The engine 1 is a cylinder injection type internal combustion engine that directly injects fuel into the cylinder. In addition, the present invention can be similarly applied to a port injection type internal combustion engine that injects fuel into the intake passage.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic which shows the structure of the intake system and exhaust system of an internal combustion engine to which this is applied about one Embodiment of the control apparatus of the internal combustion engine concerning this invention. Sectional drawing of the internal combustion engine in the embodiment. The schematic diagram which shows the structure of the variable valve mechanism in the embodiment. The fragmentary sectional view which shows the structure of the valve stop mechanism in the embodiment. The fragmentary sectional view which shows the structure of the valve stop mechanism in the embodiment. The schematic diagram which shows the drive system of the exhaust valve in the embodiment. The flowchart which shows the procedure about the action | operation process of the exhaust valve in the embodiment. The flowchart which shows the procedure about the drive restriction | limiting process of the variable valve mechanism in the embodiment. FIG. 6 is a timing chart showing changes in the operating state of the exhaust valve, the hydraulic pressure of the hydraulic pressure supply system, and the valve timing when the drive restriction process is executed in the embodiment. The flowchart which shows the one part procedure about the action | operation process of the exhaust valve in the modification of the embodiment. The schematic diagram which shows the drive system of the exhaust valve in the modification of the embodiment. The list figure which shows the operation state of the exhaust valve in the modification of the embodiment. The schematic diagram which shows the drive system of the exhaust valve in the modification of the embodiment. The list figure which shows the operation state of the exhaust valve in the modification of the embodiment. The schematic diagram which shows the drive system of the exhaust valve in the modification of the embodiment.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Engine, 2 ... Cylinder, 3 ... Cylinder head, 4 ... Intake passage, 4A ... 1st intake port, 4B ... 2nd intake port, 5A ... 1st exhaust port, 5B ... 2nd exhaust port, 6 ... Throttle valve , 7A ... Turbo side exhaust passage, 7B ... Bypass side exhaust passage, 8 ... Exhaust passage, 9 ... Catalyst, 10 ... Fuel injection valve, 11 ... Combustion chamber, 12 ... Spark plug, 20 ... Turbocharger, 21 ... Compressor, 22 ... turbine, 30 ... intake valve, 31 intake camshaft, 31A ... intake cam, 32 ... intake side valve spring, 33 ... intake side rocker arm, 33A ... roller, 35 ... lash adjuster, 50A ... turbo side exhaust valve, 50B ... bypass Side exhaust valve, 51 ... exhaust camshaft, 51A ... exhaust cam, 52 ... exhaust side valve spring, 53 ... exhaust side rocker arm, 5 A ... roller, 53C ... swinging part, 53D ... body, 53E ... torsion bar, 53F ... first hydraulic chamber, 53H ... second hydraulic chamber, 53P ... pin, 54A ... turbo side valve stop mechanism, 54B ... bypass side valve Stop mechanism, 55 ... Rush adjuster, 60 ... Communication piping, 61 ... Waste gate valve (WGV), 100 ... Variable valve mechanism, 101 ... Rotor, 102 ... Vane, 103 ... Housing, 105 ... Cam pulley, 106 ... Advance pressure Chamber 107, retard pressure chamber, 120 hydraulic control valve, 121 sleeve, 122 spool, 123 solenoid, 124 spring, 125 advance port, 126 retard port, 127 pump port, 128 ... Drain port, 150 ... Oil pump, 160 ... Oil pan, 200 ... Control device, 210 ... Accelerator position sensor Sensor, 220 ... throttle position sensor, 230 ... air flow meter, 240 ... crank position sensor, 250 ... water temperature sensor, 260 ... cam angle sensor, 270 ... supercharging pressure sensor, 280 ... exhaust pressure sensor, 300A ... oil passage, 300C ... Hydraulic passage, 300F ... first hydraulic passage, 300H ... second hydraulic passage, 310 ... control valve, 480 ... exhaust pressure sensor.

Claims (7)

A hydraulically driven variable valve mechanism for changing a valve characteristic of at least one of the intake valve and the exhaust valve; a first exhaust port and a second exhaust port provided independently for each cylinder; A turbo-side exhaust passage that guides exhaust discharged from one exhaust port to the upstream side of the turbine of the turbocharger; a bypass-side exhaust passage that guides exhaust discharged from the second exhaust port to the downstream side of the turbine; A mechanism that switches the valve operating state between an open / close state and a closed state for at least one of the exhaust valves provided in each of the first exhaust port and the second exhaust port, and shares the variable valve mechanism and the hydraulic pressure supply system A hydraulically driven valve stop mechanism that controls driving of the variable valve mechanism and the valve stop mechanism based on the engine operating state. A control system of the engine,
A control device for an internal combustion engine, which restricts driving of the variable valve mechanism when a request for switching a valve operating state to the valve stop mechanism and a request for changing a valve characteristic to the variable valve mechanism overlap. 2. The internal combustion engine according to claim 1, wherein it is determined whether or not the switching of the valve operation state by the valve stop mechanism is completed, and when it is determined that the switching is completed, the restriction on driving of the variable valve mechanism is released. Engine control device. The control device for an internal combustion engine according to claim 1 or 2, wherein when the drive of the variable valve mechanism is limited, the drive of the variable valve mechanism is stopped. The control apparatus for an internal combustion engine according to claim 1 or 2, wherein when the drive of the variable valve mechanism is limited, the drive speed of the variable valve mechanism is reduced as compared with when only the change request is present. The control of the internal combustion engine according to any one of claims 2 to 4, wherein completion of switching of the valve operating state by the valve stop mechanism is determined based on a change in pressure of the exhaust system that occurs in association with switching of the valve operating state. apparatus. The internal combustion engine according to claim 5, wherein a pressure sensor is provided in at least one of the turbo-side exhaust passage and the bypass-side exhaust passage, and the completion of switching of the valve operating state is determined based on a detection value of the pressure sensor. Control device. The said valve stop mechanism is a mechanism which has a pin withdrawn / inserted from a hole by hydraulic pressure, and switches the said valve operation state by taking in / out the said pin from the said hole. The control apparatus of the internal combustion engine described in 1.

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