JP5515793B2 - Variable mechanism control system for internal combustion engine - Google Patents

Description

  The present invention relates to a system for controlling a variable mechanism included in an internal combustion engine, and particularly to a control system for a variable mechanism including a variable compression ratio mechanism and a variable valve mechanism.

  In an internal combustion engine equipped with a variable valve mechanism, after the operation stop request (ignition switch-off) is generated, a technique for operating the variable valve mechanism to a state suitable for the next start while continuing the operation of the internal combustion engine is proposed. (For example, see Patent Document 1).

JP 2009-228667 A JP 2005-127239 A

  By the way, in an internal combustion engine equipped with an electric variable valve mechanism and an electric variable compression ratio mechanism, if the variable valve mechanism and the variable compression ratio mechanism are operated at the same time after the operation stop request is generated, the battery voltage decreases excessively. there's a possibility that.

  The present invention has been made in view of various circumstances as described above, and an object of the present invention is to provide an internal combustion engine in a variable mechanism control system including a variable valve mechanism and a variable compression ratio mechanism driven by an electric actuator. When the operation stop request is generated, the variable valve mechanism and the variable compression ratio mechanism are operated to a state suitable for the next start while avoiding an excessive decrease in the battery voltage.

  In order to solve the above-described problems, the present invention provides a variable mechanism control system for an internal combustion engine that includes a variable valve mechanism and a variable compression ratio mechanism that are driven by an electric actuator. And operating either the variable valve mechanism or the variable compression ratio mechanism to a state suitable for the next start while continuing the operation of the internal combustion engine, and after stopping the operation of the internal combustion engine, the variable valve mechanism or the variable compression ratio One of the mechanisms is operated to a state suitable for the next start.

Specifically, the present invention relates to a variable mechanism control system for an internal combustion engine including a variable valve mechanism that is driven by an electric actuator and a variable compression ratio mechanism that is driven by an electric actuator.
An operation continuation means for continuing the operation of the internal combustion engine after an internal combustion engine operation stop request is generated;
During the operation continuation period by the operation continuation means, either the variable valve mechanism or the variable compression ratio mechanism is operated to a state suitable for the next start, and after the operation continuation period by the operation continuation means ends, the variable motion Control means for operating either the valve mechanism or the variable compression ratio mechanism to a state suitable for the next start;
I was prepared to.

According to this invention, it is possible to avoid a situation in which the variable valve mechanism and the variable compression ratio mechanism operate simultaneously during the operation continuation period after the operation stop request is generated, so that it is possible to avoid an excessive decrease in the battery voltage. it can. As a result, the variable valve mechanism and the variable valve mechanism can be reliably operated to a state suitable for the next start.

  By the way, when the variable compression ratio mechanism is operated during the operation of the internal combustion engine, the combustion pressure generated in the cylinder may act as a reaction force that hinders the operation of the variable compression ratio mechanism. For example, in a variable compression ratio mechanism that changes the mechanical compression ratio (ratio of the combustion chamber volume with respect to the sum of the stroke volume and the combustion chamber volume) by changing the combustion chamber volume, the compression ratio is decreased (the combustion chamber volume is reduced). The combustion pressure acts as an assist force that assists the operation of the variable compression ratio mechanism in the case of expansion, but the operation of the variable compression ratio mechanism in the case of increasing the compression ratio (in the case of reducing the combustion chamber volume). Acts as a reaction force that prevents

  Therefore, when the compression ratio at the time when the operation stop request is generated is lower than the compression ratio suitable for the next start (hereinafter referred to as “starting reference compression ratio”), the variable compression ratio mechanism is operated during the operation continuation period. The power consumption of the electric actuator may increase on the contrary.

  Accordingly, the present invention provides a detecting means for detecting the compression ratio of the internal combustion engine (hereinafter referred to as “actual compression ratio”) when the operation stop request is generated, and the actual compression ratio detected by the detecting means is the above-described start time. A determining unit that determines whether the compression ratio is lower than the reference compression ratio may be further included. In that case, the control means selects the variable valve mechanism as the mechanism to be operated during the operation duration when the determination means makes an affirmative determination (when the actual compression ratio is lower than the starting reference compression ratio). When a negative determination is made (when the actual compression ratio is equal to or greater than the starting reference compression ratio), a variable compression ratio mechanism may be selected as a mechanism that is operated during the operation continuation period.

  According to such a configuration, it is possible to operate the variable valve mechanism and the variable compression ratio mechanism to a state suitable for the next start while minimizing the voltage drop of the battery. When the compression ratio of the internal combustion engine is changed according to the engine load, an engine load (reference engine load) at which the target compression ratio is equal to the reference compression ratio at start is obtained in advance, and when an operation stop request is generated Depending on whether the engine load of the engine is higher or lower than the reference engine load, a mechanism that operates during the operation duration may be selected.

  Further, depending on the state of the variable valve mechanism when the operation stop request is generated, the variable valve mechanism may be operable up to a state suitable for the next start without depending on the electric actuator. For example, in a variable valve mechanism that advances or retards the phase of the camshaft relative to the crankshaft, the phase of the camshaft when the operation stop request is generated is the phase suitable for the next start (hereinafter referred to as the “starting reference phase”). The camshaft phase is retarded by the rotational force of the crankshaft.

  In a variable valve mechanism that continuously changes the operating angle (or lift amount) of the intake valve or exhaust valve, the operating angle when the operation stop request is generated is the operating angle suitable for the next start (hereinafter referred to as “starting time”). If it is sufficiently large with respect to the reference operating angle, the valve operating angle is reduced to the starting reference operating angle by the reaction force of the valve spring.

  Therefore, the control means of the present invention is configured so that the variable valve mechanism when the operation stop request is generated can operate up to the starting reference phase or the starting reference operating angle without using the electric actuator. The electric actuator of the valve mechanism may not be operated.

In that case, it becomes possible to operate the variable valve mechanism and the variable compression ratio mechanism to a state suitable for the next start-up while suppressing the consumption of battery power. In the variable valve mechanism that changes the phase of the camshaft relative to the crankshaft, the rotational force of the crankshaft cannot be used after the operation of the internal combustion engine is stopped. Therefore, the operation of the electric actuator is stopped only when the variable valve mechanism is selected as the mechanism to be operated during the operation continuation period and the phase of the camshaft is advanced from the phase of the crankshaft.

  According to the present invention, in a control system for a variable mechanism including a variable valve mechanism and a variable compression ratio mechanism driven by an electric actuator, an excessive decrease in battery voltage is avoided when a request for stopping the operation of the internal combustion engine is generated. However, the variable valve mechanism and the variable compression ratio mechanism can be operated to a state suitable for the next start.

1 is a diagram showing a schematic configuration of an internal combustion engine to which the present invention is applied. It is a figure which shows an example of a variable compression ratio mechanism. It is a figure which shows an example of a variable valve mechanism. It is a timing chart which shows the execution procedure of the control at the time of an operation stop in case an actual machine compression ratio is higher than the starting reference compression ratio. It is a timing chart which shows the execution procedure of the control at the time of operation stop in case an actual machine compression ratio is lower than the reference compression ratio at the time of starting. It is a flowchart which shows an operation stop time control routine.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. The dimensions, materials, shapes, relative arrangements, and the like of the components described in the present embodiment are not intended to limit the technical scope of the invention to those unless otherwise specified.

  FIG. 1 is a diagram showing a schematic configuration of an internal combustion engine to which the present invention is applied. An internal combustion engine 1 shown in FIG. 1 is a 4-stroke cycle spark ignition internal combustion engine (gasoline engine) having a plurality of cylinders. In FIG. 1, only one cylinder among the plurality of cylinders is shown.

  The internal combustion engine 1 includes a cylinder block 2, a cylinder head 3, and a crankcase 4. A plurality of cylinders 5 are formed in the cylinder block 2. Each cylinder 5 is loaded with a piston 6 slidably in the cylinder axial direction. The piston 6 is connected to a crankshaft 7 rotatably supported by the crankcase 4 via a connecting rod 8.

  An intake port 9 and an exhaust port 10 are formed in the cylinder head 3. An intake valve 11 that opens and closes the open end of the intake port 9 and an exhaust valve 12 that opens and closes the open end of the exhaust port 10 are attached to the cylinder head 3. The intake valve 11 is driven to open and close by an intake camshaft 13 that is rotatably supported by the cylinder head 3. The exhaust valve 12 is driven to open and close by an exhaust camshaft 14 that is rotatably supported by the cylinder head 3. Further, a fuel injection valve 15 that injects fuel into the intake port 9 and a spark plug 16 that generates a spark in the cylinder 5 are attached to the cylinder head 3.

  Next, a variable compression ratio mechanism 100 for displacing the cylinder block 2 in the cylinder axial direction with respect to the crankcase 4 is provided at a connecting portion between the cylinder block 2 and the crankcase 4.

As shown in FIG. 2, the variable compression ratio mechanism 100 includes a shaft portion 101 and a cam portion having a regular circular cam profile fixed to the shaft portion 101 in a state of being eccentric with respect to the central axis of the shaft portion 101. 102, a movable bearing portion 103 having the same outer shape as the cam portion 102 and capable of rotating with respect to the shaft portion 101 and mounted in an eccentric state in the same manner as the cam portion 102, and provided concentrically with the shaft portion 101. Worm wheel 104 and worm 1 meshing with worm wheel 104
05 and a mechanism including a first electric motor (electric actuator) 106 that rotationally drives the worm 105 can be used.

  The cam portion 102 is installed in a storage hole provided in the cylinder block 2, and the movable bearing portion 103 is installed in a storage hole provided in the crankcase 4. The first electric motor 106 is fixed to the cylinder block 2 and is displaced integrally with the cylinder block 2.

  According to the variable compression ratio mechanism 100 configured as described above, the power of the first electric motor 106 is transmitted to the shaft portion 101 via the worm 105 and the worm wheel 104, and the cam portion 102 and the movable bearing in the eccentric state are transmitted. The unit 103 is driven. As a result, the cam portion 102 and the movable bearing portion 103 are relatively displaced in the cylinder axial direction, and accordingly, the cylinder block 2 and the crankcase 4 are relatively displaced in the cylinder axial direction.

  For example, when the cylinder block 2 moves away from the crankcase 4 in the cylinder axial direction, the combustion chamber volume increases and the mechanical compression ratio decreases. On the other hand, when the cylinder block 2 approaches the crankcase 4 in the cylinder axial direction, the combustion chamber volume decreases, and the mechanical compression ratio increases.

  A variable valve mechanism 200 that changes the valve opening characteristics of the intake valve 11 is attached to the cylinder head 3. Here, the configuration of the variable valve mechanism 200 will be described with reference to FIG. The configuration shown in FIG. 3 is an example of the variable valve mechanism 200, and does not limit the variable valve mechanism according to the present invention.

  In the example shown in FIG. 3, the variable valve mechanism 200 continuously changes the phase of the intake camshaft 13 with respect to the variable operating angle mechanism 201 that continuously changes the operating angle (and lift amount) of the intake valve 11 and the crankshaft 7. And a variable phase mechanism 202 that is changed in an automatic manner.

  The variable working angle mechanism 201 is disposed between the intake cam 130 and the roller rocker arm 35. The base end portion of the roller rocker arm 35 is supported by a lash adjuster 37 so as to be swingable. The distal end portion of the roller rocker arm 35 is in contact with the proximal end portion of the valve stem 11 a of the intake valve 11.

  The variable working angle mechanism 201 has a control shaft 41 disposed in parallel with the intake camshaft 13. The control shaft 41 is attached to the cylinder head 3 so as to be rotatable in the circumferential direction. A control arm 42 is fixed to the control shaft 41 with bolts 43. A part of the control arm 42 protrudes in the radial direction of the control shaft 41. A pin 45 is fixed to the protruding portion of the control arm 42. A base end portion of the intermediate arm 44 is rotatably attached to the pin 45, and the intermediate arm 44 can swing about the pin 45 as a fulcrum. A connecting shaft 54 described later is fixed to the distal end portion of the intermediate arm 44.

  A swing cam arm 50 is swingably supported on the control shaft 41. The swing cam arm 50 has a slide surface 50 a on the side facing the intake cam 130. The swing cam arm 50 has swing cam surfaces 51a and 51b on the opposite side of the slide surface 50a. The swing cam surfaces 51a and 51b are arranged such that the distance from the swing center of the swing cam arm 50 is constant, and the position of the control shaft 41 that is further away from the non-work surface 51a is the axial center of the control shaft 41. And a working surface 51b formed so as to be separated from the working surface.

Between the intake cam 130 and the variable working angle mechanism 201, the distal end portion of the intermediate arm 44 described above is located, and the connecting shaft 54 is fixed to the distal end portion. The connecting shaft 54 includes a first roller 52.
The second roller 53 is rotatably supported. At this time, the positions and diameters of the first roller 52 and the second roller 53 are determined so that the first roller 52 contacts the intake cam 130 and the second roller 53 contacts the slide surface 50 a of the swing cam arm 50. The

  Since the intermediate arm 44 rotates (oscillates) with the pin 45 as a fulcrum, the first roller 52 and the second roller 53 follow the slide surface 50 a and the peripheral surface of the intake cam 130 while maintaining a certain distance from the pin 45. Rocks.

  The swing cam arm 50 is formed with a spring seat 50b. One end of the lost motion spring 38 is in contact with the spring seat 50b. The other end of the lost motion spring 38 is fixed to the cylinder head 3. By this lost motion spring 38, the slide surface 50a of the swing cam arm 50 is pressed against the second roller 53, and the first roller 52 is pressed against the intake cam 130. As a result, the first roller 52 and the second roller 53 are positioned while being sandwiched between the slide surface 50 a and the peripheral surface of the intake cam 130.

  The roller rocker arm 35 described above is located below the swing cam arm 50. The rocker roller 36 of the roller rocker arm 35 is pressed against the swing cam surface 51 by the biasing force of the valve spring 11b and the hydraulic pressure of the lash adjuster 37 described above.

  According to the variable working angle mechanism 201 configured as described above, when the cam nose of the intake cam 130 pushes the first roller 52, the second roller 53 pushes the slide surface 50a while the intermediate arm 44 swings. That is, when the cam nose of the intake cam 130 pushes the first roller 52, the swing cam arm 50 rotates about the control shaft 41 as a support shaft.

  As a result, the contact point between the swing cam surface 51 and the rocker roller 36 moves from the non-operation surface 51a to the operation surface 51b, and the roller rocker arm 35 is pushed down. When the roller rocker arm 35 is pressed, the intake valve 11 is opened accordingly.

  The variable working angle mechanism 201 includes a second electric motor 410 that rotates the control shaft 41. When the second electric motor 410 changes the rotational position of the control shaft 41, the position of the second roller 53 on the slide surface 50a changes, and the swing range of the swing cam arm 50 during the lift operation changes.

  For example, when the second electric motor 410 rotates the control shaft 41 counterclockwise in FIG. 3, the position of the second roller 53 on the slide surface 50 a moves to the tip side of the swing cam arm 50. Accordingly, the contact position between the rocking cam surface 51 and the rocker roller 36 is changed to a position away from the action surface 51b within the range of the non-action surface 51a.

  Therefore, the amount of rotation (rotation angle) of the swing cam arm 50 required from when the cam nose of the intake cam 130 starts to push the first roller 52 until the roller rocker arm 35 starts swinging increases. As a result, the operating angle (and lift amount) of the intake valve 11 decreases while the closing timing of the intake valve 11 is fixed.

  Conversely, when the second electric motor 410 rotates the control shaft 41 in the clockwise direction in FIG. 3, the position of the second roller 53 on the slide surface 50 a moves to the proximal end side of the swing cam arm 50. Accordingly, the contact position between the swing cam surface 51 and the roller rocker arm 35 changes to a position close to the action surface 51b within the range of the non-action surface 51a.

Therefore, the amount of rotation (rotation angle) of the swing cam arm 50 required from when the cam nose of the intake cam 130 starts to push the first roller 52 until the roller rocker arm 35 starts swinging is reduced. As a result, the operating angle (and lift amount) of the intake valve 11 increases while the closing timing of the intake valve 11 is fixed.

  The variable phase mechanism 202 is provided between a cam pulley (not shown) and the intake camshaft 13. The variable phase mechanism 202 is configured by an electric motor including a casing that rotates in conjunction with the cam pulley and a rotating shaft that rotates in conjunction with the intake camshaft 13.

  According to the variable phase mechanism 202 configured as described above, when the rotation shaft of the electric motor rotates in the rotation direction of the cam pulley, the phase of the intake camshaft 13 relative to the cam pulley (crankshaft 7) is advanced. As a result, the opening / closing timing of the intake valve 11 is advanced. On the other hand, when the rotating shaft of the electric motor rotates in the direction opposite to the rotating direction of the cam pulley, the phase of the intake camshaft 13 relative to the cam pulley (crankshaft 7) is retarded. As a result, the opening / closing timing of the intake valve 11 is retarded. Hereinafter, the variable phase mechanism 202 may be referred to as a third electric motor 202.

  Returning to FIG. 1, the internal combustion engine 1 is provided with an electronic control unit (ECU) 20 for controlling the operating state of the internal combustion engine 1. The ECU 20 is supplied with output signals from various sensors such as a crank position sensor 21, an accelerator position sensor 22, an ignition switch 23, a water temperature sensor 24, a lift sensor 25, and the like.

  The crank position sensor 21 is a sensor that outputs an electrical signal correlated with the rotational position (rotation angle) of the crankshaft 7. The accelerator position sensor 22 is a sensor that outputs an electrical signal correlated with an operation amount (accelerator opening) of an accelerator pedal (not shown). The water temperature sensor 24 is a sensor that outputs an electrical signal that correlates with the temperature of the cooling water circulating in the internal combustion engine 1. The lift sensor 25 is disposed in the crankcase 4 in the vicinity of the connection portion with the cylinder block 2, and is correlated with the lift amount of the cylinder block 2 relative to the crankcase 4 (the displacement amount toward the top dead center side in the cylinder axis direction). It is a sensor that outputs a signal.

  Further, the ECU 20 is electrically connected to various devices such as the fuel injection valve 15, the spark plug 16, the first electric motor 106, the second electric motor 410, and the variable phase mechanism (third electric motor) 202 described above. Yes. The ECU 20 controls the fuel injection valve 15, the spark plug 16, the first electric motor 106, the second electric motor 410, and the variable phase mechanism (third electric motor) 202 based on the output signals of the various sensors described above.

  For example, the ECU 20 performs high expansion ratio control in order to increase the thermal efficiency when the internal combustion engine 1 is in a low load operation state. In the high expansion ratio control, the ECU 20 controls the first electric motor 106 to increase the mechanical compression ratio of the internal combustion engine 1 and also the second electric motor 410 and the third electric motor to decrease the effective compression ratio of the internal combustion engine 1. 202 is controlled.

  Specifically, the ECU 20 controls the first electric motor 106 so that the cylinder block 2 is displaced toward the bottom dead center, and the second electric motor so that the closing timing of the intake valve 11 is delayed until the middle of the compression stroke. The motor 410 is controlled.

  When such high expansion ratio control is performed, the expansion ratio can be increased while the effective compression ratio is maintained in a range where knocking can be avoided.

Further, the ECU 20 performs the variable compression ratio mechanism 100 and the variable valve mechanism when a request for stopping the operation of the internal combustion engine 1 is generated, in other words, when the ignition switch 23 is switched from ON to OFF. The control at the time of operation stop which operates 200 to the state suitable for the next start is executed.

  In the control at the time of operation stop, the ECU 20 performs the operation continuation processing for continuing the operation of the internal combustion engine 1 even after the operation stop request is generated, the mechanical compression ratio becomes a value suitable for the next start (startup reference compression ratio), and the intake valve 11 is a value suitable for the next start (a reference working angle at the start), and the closing timing of the intake valve 11 is a valve closing timing suitable for the next start (hereinafter referred to as a “starting reference valve closing timing”). ), An optimization process for controlling the first electric motor 106, the second electric motor 410, and the third electric motor 202 is performed.

  The starting reference compression ratio, starting reference working angle, and starting reference valve closing timing are within the range where the compression end temperature and the intake air amount can be cold-started, and knocking or pre- It is a value determined so as to fall within a range where ignition can be avoided, and is a value determined in advance by an adaptation process using an experiment or the like.

  If such control at the time of shutdown is executed, at the next start, the startability decreases as the cranking torque increases, the load on the starter motor increases, the vibration and noise increase due to the occurrence of knocking, the unburned fuel It is possible to mitigate an increase in exhaust emission due to an increase in component emissions.

  By the way, if the 1st electric motor 106, the 2nd electric motor 410, and the 3rd electric motor 202 are operated simultaneously during the driving | running | working continuation process execution period, a battery voltage may fall excessively. If the battery voltage decreases excessively, the ECU 20 may not be able to continue normal operation and may be reset. In that case, there is a possibility that the state of the variable compression ratio mechanism 100 and the variable valve mechanism 200 cannot be made suitable for the next start.

  Therefore, in the control at the time of operation stop in the present embodiment, the ECU 20 operates only one of the variable compression ratio mechanism 100 and the variable valve mechanism 200 during the operation continuation process execution period, and changes after the operation continuation process execution period ends. Either the compression ratio mechanism 100 or the variable valve mechanism 200 is operated.

  When the control at the time of operation stop is executed by such a method, an excessive decrease in the battery voltage can be avoided, so that the variable compression ratio mechanism 100 and the variable valve mechanism 200 are surely brought into a state suitable for the next start. It becomes possible to operate.

  The ECU 20 is operated during the operation continuation process execution period based on the determination result of whether or not the output signal (actual machine compression ratio) of the lift sensor 25 when the operation stop request is generated is lower than the starting reference compression ratio. A mechanism may be selected.

  When the actual machine compression ratio is lower than the starting reference compression ratio, the variable compression ratio mechanism 100 needs to increase the actual machine compression ratio to the starting reference compression ratio (reduce the combustion chamber volume). On the other hand, when the actual machine compression ratio is equal to or higher than the starting reference compression ratio, the variable compression ratio mechanism 100 needs to reduce the actual machine compression ratio to the starting reference compression ratio (enlarge the combustion chamber volume).

  Here, in the mechanism that changes the combustion chamber volume, such as the variable compression ratio mechanism 100 of the present embodiment, the combustion pressure generated in the cylinder 5 acts to expand the combustion chamber volume (lower the mechanical compression ratio). To do. Therefore, when the variable compression ratio mechanism 100 expands the combustion chamber volume, the combustion pressure acts as an assisting force that assists the operation of the variable compression ratio mechanism 100, but the variable compression ratio mechanism 100 reduces the combustion chamber volume. The combustion pressure acts as a reaction force that hinders the operation of the variable compression ratio mechanism 100.

  Further, when the variable phase mechanism 202 changes the phase of the intake camshaft 13, the variable phase mechanism 202 receives a force from the crankshaft 7 to advance the cam pulley from the intake camshaft 13, and the valve spring 11b. To receive a force to retard the intake camshaft 13 from the cam pulley. Therefore, when the phase of the intake camshaft 13 is advanced, the above-described force acts as a reaction force that hinders the operation of the variable phase mechanism 202. However, when the phase of the intake camshaft 13 is retarded, the above-described force is applied. Acts as an assist force for assisting the operation of the variable phase mechanism 202.

  When the actual machine compression ratio is lower than the starting reference compression ratio (when the internal combustion engine 1 is in a high-load operation state), the phase of the intake camshaft 13 is retarded from the starting reference phase, and the actual machine compression ratio is When it is higher than the starting reference compression ratio (when the internal combustion engine 1 is in a low load operation state or an idling operation state), the phase of the intake camshaft 13 is advanced from the starting reference phase.

  On the other hand, when the variable working angle mechanism 201 changes the working angle of the intake valve 11, the urging force of the valve spring 11 b acts on the variable working angle mechanism 201. Specifically, when the variable working angle mechanism 201 increases the working angle of the intake valve 11, the urging force of the valve spring 11b acts as a reaction force that hinders the operation of the variable working angle mechanism 201. When the operating angle of the intake valve 11 is reduced, the urging force of the valve spring 11 b acts as an assist force that assists the operation of the variable operating angle mechanism 201. However, the above-mentioned tendency is constant regardless of whether the internal combustion engine 1 is operating or is stopped.

  Therefore, when the actual machine compression ratio is higher than the starting reference compression ratio (when the operation stop request is generated when the internal combustion engine 1 is in the low load operation state or the idle operation state), the ECU 20 is as shown in FIG. In addition, the variable compression ratio mechanism 100 is operated during the operation continuation process execution period, and the variable working angle mechanism 201 and the variable phase mechanism 202 are operated after the operation continuation process execution period ends (after the fuel cut (FC) is performed). I made it.

  In that case, the combustion pressure generated in the cylinder 5 acts as an assisting force that assists the operation of the variable compression ratio mechanism 100, so that the voltage applied to the first electric motor 106 can be kept low. As a result, it is possible to avoid a situation in which the battery voltage decreases excessively during the operation continuation process execution period.

  The phase of the intake camshaft 13 may be changed during the operation continuation process execution period. During the operation continuation processing period, the phase of the intake camshaft 13 can be retarded to the starting reference phase by using the urging force of the valve spring 1b and the rotational force of the crankshaft 7. Therefore, the phase of the intake camshaft 13 can be retarded to the starting reference phase without operating the third electric motor 202. Therefore, only the first electric motor 106 is operated during the operation continuation process execution period, and only the second electric motor 410 is operated after the operation continuation process execution period ends. As a result, it is possible to reduce the decrease amount of the battery voltage after the end of the operation continuation process execution period while suppressing the decrease amount of the battery voltage during the operation continuation process execution period.

  Further, when the actual machine compression ratio is lower than the starting reference compression ratio (when the operation stop request is generated when the internal combustion engine 1 is in a high load operation state), the ECU 20 continues the operation as shown in FIG. The variable working angle mechanism 201 and the variable phase mechanism 202 are operated during the process execution period, and the variable compression ratio mechanism 100 is operated during the operation stop after the end of the operation continuation process execution period (after the fuel cut (FC) is performed). I made it.

In that case, it is necessary to operate the variable working angle mechanism 201 and the variable phase mechanism 202 during the operation continuation processing execution period, but the urging force of the valve spring 11b acts as an assisting force that assists the operation of the variable working angle mechanism 201. Therefore, the applied voltage of the second electric motor 410 can be reduced.

  The phase of the intake camshaft 13 may be changed after the operation continuation process execution period ends. Since the rotational force of the crankshaft 7 acts as a reaction force that hinders the operation of the variable phase mechanism 202 (the operation of advancing the intake camshaft 13) during the operation continuation processing execution period, the power consumption of the third electric motor 202 increases. there is a possibility. On the other hand, if the phase of the intake camshaft 13 is changed after the operation continuation process execution period ends, the phase of the intake camshaft 13 can be changed by a lower applied voltage than during the operation continuation process execution period. Therefore, it is possible to further reduce the amount of decrease in the battery voltage during the operation continuation process execution period while avoiding an excessive decrease in the battery voltage after the operation continuation process execution period ends.

  Hereinafter, the execution procedure of the control at the time of operation stop in the present embodiment will be described with reference to FIG. FIG. 6 is a flowchart showing a control routine at the time of operation stop. This routine is a routine that is stored in advance in the ROM of the ECU 20, and is a routine that is executed by the ECU 20 when the ignition switch is switched from ON to OFF.

  In the operation stop time control routine of FIG. 6, the ECU 20 first determines in step S101 whether or not the ignition switch 23 has been switched from on (ON) to off (OFF). If a negative determination is made in S101, the ECU 20 ends the execution of this routine. On the other hand, if an affirmative determination is made in S101, the ECU 20 proceeds to S102.

  In S102, the ECU 20 executes an operation continuation process. Specifically, the ECU 20 continues the operation of the fuel injection valve 15 and the spark plug 16. In this case, the target injection amount and the target ignition timing are set to the target injection amount and the target ignition timing when the internal combustion engine 1 is in the idling operation state.

  In S103, the ECU 20 reads the output signal (actual machine compression ratio) of the lift sensor 25. Subsequently, the ECU 20 proceeds to S104, and determines whether or not the actual machine compression ratio is lower than the starting reference compression ratio. If an affirmative determination is made in S104, the ECU 20 proceeds to S105.

  In S105, the ECU 20 operates the second electric motor 410 to change the operating angle of the intake valve 11 to the starting reference operating angle, and the third electric motor to change the phase of the intake camshaft 13 to the starting reference phase. The motor 202 is operated.

  In S106, it is determined whether or not the actual operating angle of the intake valve 11 (the rotational position of the control shaft 41) is equal to the starting reference operating angle and the actual phase of the intake camshaft 13 is equal to the starting reference phase. If a negative determination is made in S106, the ECU 20 returns to S105. If an affirmative determination is made in S106, the ECU 20 proceeds to S107.

  In S107, the ECU 20 stops the operation of the variable working angle mechanism 201 and the variable phase mechanism 202 (the second electric motor 410 and the third electric motor 202) and ends the operation continuation process (deactivation of the fuel injection valve 15, And the operation of the spark plug 16 is stopped).

  In S108, the ECU 20 operates the variable compression ratio mechanism 100 (first electric motor 106) so as to change the actual machine compression ratio to the starting reference compression ratio.

If a negative determination is made in S104, the ECU 20 proceeds to S109.
In S109, the ECU 20 operates the variable compression ratio mechanism 100 (first electric motor 106) to change the actual machine compression ratio to the starting reference compression ratio.

  In S110, the ECU 20 determines whether or not the actual machine compression ratio is equal to the starting reference compression ratio. If a negative determination is made in S110, the ECU 20 returns to S109. If an affirmative determination is made in S110, the ECU 20 proceeds to S111.

  In S111, the ECU 20 stops the operation of the variable compression ratio mechanism 100 (first electric motor 106) and ends the operation continuation process (stops the operation of the fuel injection valve 15 and stops the operation of the spark plug 16).

  In S112, the ECU 20 operates the second electric motor 410 in order to change the operating angle of the intake valve 11 to the starting reference operating angle, and the third electric motor to change the phase of the intake camshaft 13 to the starting reference phase. The motor 202 is operated.

  As described above, when the ECU 20 executes the control routine at the time of operation stop, the operation continuation means, control means, and determination means according to the present invention are realized. As a result, it is possible to operate the variable compression ratio mechanism 100 and the variable valve mechanism 200 to a state suitable for the next start while avoiding an excessive decrease in the battery voltage when an operation stop request for the internal combustion engine 1 is generated.

  In the embodiment described above, the example in which the present invention is applied to a spark ignition type internal combustion engine (gasoline engine) has been described. However, the present invention may be applied to a compression ignition type internal combustion engine (diesel engine). In short, the present invention is applicable to any internal combustion engine having a plurality of variable mechanisms driven by an electric actuator.

DESCRIPTION OF SYMBOLS 1 Internal combustion engine 2 Cylinder block 3 Cylinder head 4 Crankcase 5 Cylinder 6 Piston 7 Crankshaft 8 Connecting rod 9 Intake port 10 Exhaust port 11 Intake valve 11b Valve spring 12 Exhaust valve 13 Intake camshaft 14 Exhaust camshaft 15 Fuel injection valve 16 Spark plug 25 Lift sensor 100 Variable compression ratio mechanism 106 First electric motor 130 Intake cam 200 Variable valve mechanism 201 Variable working angle mechanism 202 Variable phase mechanism 202 Third electric motor 410 Second electric motor

Claims (2)

In a variable mechanism control system for an internal combustion engine comprising a variable valve mechanism driven by an electric actuator and a variable compression ratio mechanism driven by an electric actuator,
An operation continuation means for continuing the operation of the internal combustion engine after an internal combustion engine operation stop request is generated;
During the operation continuation period by the operation continuation means, either the variable valve mechanism or the variable compression ratio mechanism is operated to a state suitable for the next start, and after the operation continuation period by the operation continuation means ends, the variable motion Control means for operating either the valve mechanism or the variable compression ratio mechanism to a state suitable for the next start;
Detecting means for detecting the compression ratio of the internal combustion engine at the time when the operation stop request is generated;
Discrimination means for discriminating whether or not the compression ratio detected by the detection means is lower than a reference compression ratio at start which is a compression ratio suitable for next start;
Bei to give a,
The control means selects a variable valve mechanism as a mechanism to be operated during the operation continuation period when the determination means is affirmative, and operates during the operation continuation period when the determination means is negative. A variable mechanism control system for an internal combustion engine, wherein a variable compression ratio mechanism is selected as Oite to claim 1, wherein if is operable to condition the state of the variable valve mechanism during operation stop request generated is suitable for the next start-up without depending on the power of the electric actuator, the variable A variable mechanism control system for an internal combustion engine, wherein power is not supplied to an electric actuator for a valve mechanism.

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