JP2011032905A - Variable valve timing control device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To shorten a time required for the completion of locking by improving the response of a phase control when the locking is requested in a variable valve timing control device with an intermediate lock mechanism which controls both the driving hydraulic pressure of a VCT phase and the driving hydraulic pressure of the lock pin by a single hydraulic control valve. <P>SOLUTION: The variable valve timing control device locks the VCT phase at the intermediate lock phase by the lock pin 58 by performing a lock pin projecting control while returning the VCT phase toward the intermediate lock phase after performing, by an F/B control, a phase control at request for locking which temporarily moves, at occurrence of the request for locking, the VCT phase to the target phase passing, a predetermined amount, through the intermediate loch phase. The control duty of the hydraulic control valve 25 when the phase control is performed at request for locking is set to a control duty which increases the speed of the movement of the VCT phase over the normal phase control by setting the proportional gain of the phase control at the time of request for locking larger than the proportional gain of the normal phase control. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a variable valve timing for an internal combustion engine provided with an intermediate lock mechanism that locks the rotational phase of the camshaft relative to the crankshaft of the internal combustion engine (hereinafter referred to as “VCT phase”) with an intermediate lock phase located within the adjustable range. The invention relates to a control device.

  Conventionally, in a hydraulically driven variable valve timing device, as described in Patent Document 1 (Japanese Patent Laid-Open No. 9-324613) and Patent Document 2 (Japanese Patent Laid-Open No. 2001-159330), the engine is stopped. The lock phase is set approximately in the middle of the adjustable range of the VCT phase to expand the adjustable range of the valve timing (VCT phase). In this system, the intermediate lock phase that is locked when the engine is stopped is set to a phase that is suitable for starting, and the engine is started with this intermediate lock phase. Then, the lock is released and the VCT phase is feedback-controlled to the target phase set according to the engine operating state. Then, lock control for locking the VCT phase with the intermediate lock phase is executed when the engine is stopped or when a lock request is generated during idle operation.

JP-A-9-324613 JP 2001-159330 A

  In order to ensure that the VCT phase is locked at the intermediate lock phase when the lock request is generated, the applicant assigns the camshaft phase to the target phase that has passed the intermediate lock phase by a predetermined amount when the lock request occurs. Researching lock control technology that locks the VCT phase with the intermediate lock phase by performing lock pin protrusion control that causes the lock pin to protrude while performing phase control at the time of lock request to move, and returning toward the intermediate lock phase・ Developed (Japanese Patent Application No. 2008-31844).

  In addition, the variable valve timing device with an intermediate lock mechanism separately includes a phase control hydraulic control valve that controls the hydraulic pressure that drives the VCT phase and a lock control hydraulic control valve that controls the hydraulic pressure that drives the lock pin. In order to reduce the number of parts and reduce the cost, the applicant has an intermediate lock mechanism that controls both the drive hydraulic pressure of the VCT phase and the drive hydraulic pressure of the lock pin with a single hydraulic control valve. Is researching and developing a variable valve timing device (Japanese Patent Application No. 2008-31844). In this case, in accordance with the control amount of the hydraulic control valve, a retard mode control region for driving the VCT phase in the retard direction, a hold mode control region for keeping the VCT phase constant, and the VCT phase in the advance direction The control region is divided into an advance angle control region for driving the lock pin and a lock mode control region for biasing the lock pin in the protruding direction which is the lock direction.

  In such a variable valve timing device configured to control both the drive hydraulic pressure of the VCT phase and the drive hydraulic pressure of the lock pin with one hydraulic control valve, the camshaft phase is temporarily set to the intermediate lock phase when a lock request is generated. Lock to lock the VCT phase with the intermediate lock phase by performing lock pin protrusion control that causes the lock pin to protrude while returning to the intermediate lock phase after performing phase control at the time of lock request to move to the target phase that has passed only a fixed amount When the control is performed, the phase control at the time of the lock request is performed in the retard mode control area or the advance mode control area, and then the lock pin protrusion control is performed by switching to the lock mode control area.

  In this case, in normal phase control in which the VCT phase is feedback-controlled to a target phase set in accordance with the engine operating state, the phase control response (control gain, etc.) so as to suppress overshoot in which the VCT phase greatly exceeds the target phase. Therefore, if the phase control at the time of lock request is performed with the feedback control with the same responsiveness as the normal phase control, it takes time to move the VCT phase to the target phase. The time will be longer. In particular, for lock requests that occur when the engine is stopped, the time until the engine rotation stops (the time required to secure the hydraulic pressure necessary to perform the lock control) is short. If you don't complete it, you can't lock it.

  Therefore, the problem to be solved by the present invention is to increase the responsiveness of phase control at the time of a lock request so that the time until lock completion can be shortened.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a hydraulically driven variable valve that adjusts the valve timing by changing the rotational phase of the camshaft (hereinafter referred to as “VCT phase”) with respect to the crankshaft of the internal combustion engine. An internal combustion engine comprising: a timing device; a lock pin that locks the VCT phase with an intermediate lock phase located within the adjustable range; and a hydraulic control valve that controls the hydraulic pressure that drives the variable valve timing device and the lock pin In the variable valve timing control device, when a predetermined phase control execution condition is satisfied, a phase control (hereinafter referred to as “normal control”) that controls the hydraulic control valve so that the VCT phase coincides with a target phase set according to an operation condition. VCT phase control means for executing "phase control") and the VCT phase once in the middle when a lock request is generated The lock pin protruding control is performed so that the lock pin protrudes while returning to the intermediate lock phase after performing the phase control at the time of the lock request to move the lock phase to the target phase that has passed the predetermined amount. Lock control means for controlling the VCT phase to lock at the intermediate lock phase, and the lock control means controls the control amount of the hydraulic control valve when performing phase control at the time of the lock request. The control amount is set to be different from that at the time of phase control. In this way, it is possible to shorten the time until lock completion by speeding up the responsiveness of phase control at the time of a lock request.

  Specifically, as in claim 2, when performing the phase control at the time of the lock request, the control amount of the hydraulic control valve is set to a control amount that makes the movement of the VCT phase faster than in the case of the normal phase control. You may do it.

  Alternatively, as in the third aspect, the phase control at the time of lock request is executed by feedback control including at least a proportional term as in the case of normal phase control, and the gain of the proportional term of the phase control at the time of lock request May be set to a gain larger than the gain of the proportional term of normal phase control.

  Alternatively, as in claim 4, the phase control at the time of the lock request is executed by open loop control, and the control amount of the phase control at the time of the lock request is set to make the movement of the VCT phase faster than in the case of the normal phase control. You may make it set to the control amount to perform.

Alternatively, when performing phase control at the time of requesting lock, the target phase may be offset in the direction of accelerating the motion of the VCT phase with respect to the target phase.
In any of the second to fifth aspects, the responsiveness of the phase control at the time of the lock request can be accelerated.

  By the way, as the responsiveness of the phase control at the time of lock request becomes faster, the overshoot in which the VCT phase passes the target phase by the phase control at the time of lock request increases, so the VCT phase at the start of lock pin protrusion control and the target phase The deviation becomes large, and it takes a long time from the start of lock pin protrusion control to the completion of lock.

  Therefore, as in claim 6, when performing phase control at the time of lock request, when the deviation between the VCT phase and the target phase is within a predetermined value and the change speed of the VCT phase to the target phase is a predetermined value or more, Therefore, it is determined that it is not necessary to speed up the response of the phase control at the time of the lock request, and the control amount of the hydraulic control valve may be set to the same control amount as in the case of the normal phase control. In this way, it is possible to prevent the responsiveness of the phase control at the time of the lock request from being accelerated excessively, to prevent the overshoot that the VCT phase passes the target phase from becoming too large, and the lock pin can be prevented by an excessive overshoot. It can be prevented that the time from the start of the protrusion control to the completion of the lock becomes too long.

  According to a seventh aspect of the present invention, the hydraulic control valve includes a hydraulic control valve function for phase control that controls the hydraulic pressure that drives the VCT phase, and a hydraulic control valve for lock control that controls the hydraulic pressure that drives the lock pin. Using a hydraulic control valve that integrates the function, the control mode of the retard mode that drives the VCT phase in the retard direction according to the control amount of the hydraulic control valve, and the holding mode that keeps the VCT phase constant The control region may be divided into an advance mode control region that drives the VCT phase in the advance direction, and a lock mode control region that biases the lock pin in the protruding direction that is the lock direction. In this way, it is possible to control both the hydraulic pressure for driving the VCT phase and the hydraulic pressure for driving the lock pin with a single hydraulic control valve, thereby satisfying the demand for reducing the number of parts and reducing the cost.

FIG. 1 is a schematic configuration diagram of the entire engine control system used in the first and second embodiments of the present invention. FIG. 2 is a longitudinal side view for explaining the configuration of the variable valve timing device and the hydraulic control circuit. FIG. 3 is a longitudinal front view of the variable valve timing device. FIG. 4 is a view for explaining the functions of the lock pin (advance limit pin) and the retard limit pin. FIG. 5A is a diagram illustrating a switching pattern of the advance port, retard port, and lock pin control port of the hydraulic control valve, and FIG. 5B shows the lock mode, advance mode, holding mode, and retard angle. It is a control characteristic figure of a hydraulic control valve explaining relation between four control fields of a mode, and a phase change speed. FIG. 6 is a flowchart for explaining the processing flow of the lock control routine of the first embodiment. FIG. 7 is a time chart showing an example of phase control at the time of lock request according to the first embodiment in comparison with the comparative example. FIG. 8 is a flowchart for explaining the processing flow of the lock control routine of the second embodiment.

  Hereinafter, two Examples 1 and 2 which embody the form for implementing this invention are demonstrated.

A first embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 1, in an engine 11 that is an internal combustion engine, power from a crankshaft 12 is transmitted to an intake side camshaft 16 and an exhaust side camshaft 17 via sprockets 14 and 15 by a timing chain 13. It is like that. However, the intake side camshaft 16 is provided with a variable valve timing device 18 (VCT) that adjusts the advance amount (VCT phase) of the intake side camshaft 16 with respect to the crankshaft 12.

  A cam angle sensor 19 that outputs a cam angle signal pulse at every predetermined cam angle is installed on the outer peripheral side of the intake side cam shaft 16. On the other hand, on the outer peripheral side of the crank shaft 12, every predetermined crank angle is provided. A crank angle sensor 20 that outputs a crank angle signal pulse is provided. Output signals from the cam angle sensor 19 and the crank angle sensor 20 are input to the engine control circuit 21. The engine control circuit 21 functions as a VCT phase calculation means in the claims, and based on the phase difference between the output signal pulses of the cam angle sensor 19 and the crank angle sensor 20, the actual valve timing (actual VCT phase) of the intake valve. ) And the engine rotation speed is calculated based on the frequency (pulse interval) of the output pulse of the crank angle sensor 20. In addition, output signals from various sensors (intake pressure sensor 22, cooling water temperature sensor 23, throttle sensor 24, etc.) for detecting the engine operating state are input to the engine control circuit 21.

  The engine control circuit 21 performs fuel injection control and ignition control according to the engine operating state detected by the various sensors, and also performs variable valve timing control (VCT phase feedback control), and actual valve timing (actual control of the intake valve). The hydraulic pressure for driving the variable valve timing device 18 is feedback controlled so that the (VCT phase) matches the target valve timing (target VCT phase) set according to the engine operating state.

Next, the configuration of the variable valve timing device 18 will be described with reference to FIGS.
A housing 31 of the variable valve timing device 18 is fastened and fixed with bolts 32 to a sprocket 14 that is rotatably supported on the outer periphery of the intake camshaft 16. Thereby, the rotation of the crankshaft 12 is transmitted to the sprocket 14 and the housing 31 via the timing chain 13, and the sprocket 14 and the housing 31 rotate in synchronization with the crankshaft 12.

  On the other hand, a rotor 35 is fastened and fixed to one end of the intake side camshaft 16 with a bolt 37. The rotor 35 is housed in the housing 31 so as to be relatively rotatable.

  As shown in FIG. 3, a plurality of vane storage chambers 40 are formed inside the housing 31, and each vane storage chamber 40 is retarded from the advance chamber 42 by the vane 41 formed on the outer peripheral portion of the rotor 35. It is partitioned into a chamber 43. At both sides of at least one vane 41, a stopper portion 56 is formed that restricts the relative rotation range of the rotor 35 (vane 41) with respect to the housing 31, and the actual VCT phase (cam shaft phase) is adjusted by the stopper portion 56. The most retarded angle phase and the most advanced angle phase of the possible range are regulated.

  The variable valve timing device 18 is provided with an intermediate lock mechanism 50 that locks the VCT phase at an intermediate lock phase located between the most retarded angle phase and the most advanced angle phase of the adjustable range (for example, substantially in the middle). Yes. The configuration of the intermediate lock mechanism 50 will be described. Any one (or a plurality of) vanes 41 are provided with a lock pin accommodation hole 57, and the lock pin accommodation hole 57 has a housing 31, a rotor 35 (vane 41), and the like. A lock pin 58 for locking the relative rotation of the sprocket 14 is accommodated so as to protrude, and the lock pin 58 protrudes toward the sprocket 14 and fits into the lock hole 59 (see FIG. 4) of the sprocket 14, so that the VCT phase is It is locked at an intermediate lock phase located approximately in the middle of the adjustable range. This intermediate lock phase is set to a phase suitable for starting the engine 11. The lock hole 59 may be provided in the housing 31.

  As shown in FIG. 4, the lock pin 58 is urged in the lock direction (projection direction) by the spring 62. Further, between the outer peripheral portion of the lock pin 58 and the lock pin accommodation hole 57, an unlocking hydraulic chamber for controlling the hydraulic pressure for driving the lock pin 58 in the unlocking direction is formed.

  In the first embodiment, the lock pin 58 also functions as an advance limit pin that prevents the VCT phase controlled on the retard side from the intermediate lock phase from inadvertently moving beyond the intermediate lock phase to the advance side. Then, the advance angle limiting groove 63 shallower than the lock hole 59 is formed so as to extend continuously to the predetermined phase C near the most retarded angle phase, and the lock pin 58 (advance angle limit pin). ) Is fitted in the advance angle limiting groove 63, the range of the VCT phase controlled on the retard side from the intermediate lock phase is limited to the range from the intermediate lock phase to the predetermined phase C near the most retarded phase. It is like that.

  When the target phase exceeds the predetermined phase C and is set to the most retarded phase side, the lock pin 58 (advance angle limiting pin) is extracted from the advance angle limiting groove 63 by hydraulic pressure, so that the VCT phase is the most retarded angle. Move to the phase side. Further, when the target phase is set to the advance side with respect to the intermediate lock phase, the lock pin 58 (advance limit pin) is completely extracted from the lock hole 59 by hydraulic pressure, and the VCT phase is advanced from the intermediate lock phase. To move to the side.

  Similarly, a retard limit pin 64 that prevents the VCT phase controlled on the advance side from inadvertently moving to the retard side and, for example, two stages of retard limit grooves 65 a and 65 b are provided. By fitting the angle limiting pin 64 into one of the retardation limiting grooves 65a and 65b, the range of the VCT phase controlled on the advance side is limited to, for example, two stages.

  One of the two-stage retardation restriction grooves 65a and 65b may be omitted to provide only one retardation restriction groove, or three or more retardation restriction grooves. Further, the advance angle limiting groove 63, the retard angle limiting grooves 65a and 65b, and the retard angle limiting pin 64 may be omitted.

  In the configuration example of FIG. 4, the retard angle limiting grooves 65a and 65b extend from the most advanced angle phase to the predetermined phase B and A on the retard angle side beyond the intermediate lock phase. The advance angle limit pin) and the retard angle limit pin 64 are fitted into the lock hole 59 and the second angle (the deeper groove) delay angle limit groove 65b, respectively.

  Further, as shown in FIG. 2, the housing 31 includes a spring 55 such as a torsion coil spring as an urging means for assisting (assisting) the hydraulic pressure for relatively rotating the rotor 35 in the advance angle direction during advance angle control. Is provided. In the variable valve timing device 18 for the intake valve, the torque of the intake side camshaft 16 acts in a direction that retards the VCT phase. Therefore, the spring 55 has a direction opposite to the torque direction of the intake side camshaft 16. Will be urged in the advance direction.

  In the first embodiment, as shown in FIG. 4, the range in which the urging force of the spring 55 acts is set to the range from the most retarded phase to the almost intermediate lock phase, and restart after an abnormal stop such as engine stall Assuming the fail safe at the time, when starting with the actual VCT phase retarded from the intermediate lock phase with the lock pin 58 removed from the lock hole 59, during the cranking by the starter (not shown), The spring 55 is configured so that the lock pin 58 can be fitted into the lock hole 59 and locked by assisting the advance operation of advancing the actual VCT phase from the retard side to the intermediate lock phase by the spring force of the spring 55.

  On the other hand, when starting with the actual VCT phase on the advance side from the intermediate lock phase, the torque on the intake side camshaft 16 acts in the retarding direction during cranking, so the actual VCT phase is caused by the torque on the intake side camshaft 16. Can be retarded from the advance side to the intermediate lock phase to lock the lock pin 58 into the lock hole 59.

  In the first embodiment, the hydraulic control valve that controls the hydraulic pressure that drives the VCT phase of the variable valve timing device 18, the lock pin 58, and the retard limit pin 64 is used for phase control that controls the hydraulic pressure that drives the VCT phase. The oil pressure control valve 25 and the oil pressure control valve function for controlling the oil pressure for driving the lock pin 58 are integrated, and the oil pump 28 driven by the power of the engine 11 Oil (operating oil) in the oil pan 27 is pumped up and supplied to the hydraulic control valve 25. The hydraulic control valve 25 is constituted by, for example, an 8-port / four-position type spool valve, and, as shown in FIG. 5, the lock modes L1, L2, the advance mode are controlled according to the control duty (control amount) of the hydraulic control valve 25. The control area is divided into four control areas: angular mode A, holding mode H, and retarding mode R.

  In the control region of the lock modes L1 and L2, the oil supply oil passage to the unlocking hydraulic chamber in the lock pin accommodating hole 57 is shut off, and the hydraulic pressure in the unlocking hydraulic chamber in the lock pin accommodating hole 57 is released. The lock pin 58 is protruded in the locking direction by the spring 62.

  Furthermore, the control region of the lock modes L1 and L2 is the control region of the oil filling mode L1 that supplies oil to the advance chamber 42 by opening the oil supply oil passage to the advance chamber 42 while protruding the lock pin 58. The lock pin 58 is projected into the control region of the lock holding mode L2 in which the oil supply oil passages of both the advance chamber 42 and the retard chamber 43 are shut off and the oil pressure in the chambers 42, 43 is maintained. Yes.

  In the control region of the advance angle mode A, the oil supply oil passage to the retard chamber 43 is shut off, the retard port of the hydraulic control valve 25 is connected to the drain port, and the oil pressure in the retard chamber 43 is released. According to the control duty of the hydraulic control valve 25, the oil supply oil passage to the advance chamber 42 is opened, oil is supplied to the advance chamber 42, and the oil pressure in the advance chamber 42 is changed to change the actual VCT phase. Advance the angle.

In the control region of the holding mode H, the oil supply oil passages of both the advance chamber 42 and the retard chamber 43 are shut off, and the oil pressures of both the chambers 42 and 43 are held so that the actual VCT phase does not move. .
In the control region of the retard angle mode R, the oil supply oil passage to the advance chamber 42 is shut off, the advance port of the hydraulic control valve 25 is connected to the drain port, and the hydraulic pressure in the advance chamber 42 is released. Depending on the control duty of the hydraulic control valve 25, the oil supply oil passage to the retard chamber 43 is opened, oil is supplied to the retard chamber 43, and the hydraulic pressure in the retard chamber 43 is changed to change the actual VCT phase. Is retarded.

  In the control region other than the lock modes L1 and L2 (advance mode A, hold mode H, retard mode R), the oil supply oil passage to the lock release hydraulic chamber in the lock pin accommodation hole 57 is opened to release the lock. The hydraulic chamber is filled with oil to increase the hydraulic pressure in the unlocking hydraulic chamber, and the lock pin 58 is extracted from the lock hole 59 by the hydraulic pressure to unlock the lock pin 58.

  In the first embodiment, the control mode is switched in the order of the lock modes L1 and L2, the advance mode A, the hold mode H, and the retard mode R as the control duty of the hydraulic control valve 25 increases. However, for example, as the control duty of the hydraulic control valve 25 increases, the control mode is switched in the order of the retard mode R, the holding mode H, the advance mode A, the lock modes L1 and L2, or The control mode may be switched in the order of the lock modes L1, L2, the retard mode R, the holding mode H, and the advance mode A by switching the order of the retard mode R and the advance mode A.

  The engine control circuit 21 functions as VCT phase control means in the claims, and when a predetermined phase control execution condition is satisfied, the actual VCT phase of the intake side camshaft 16 (the actual valve timing of the intake valve). ) Is controlled to F / B by, for example, PD control or the like including at least a proportional term so that the control duty (control amount) of the hydraulic control valve 25 matches the target phase (target valve timing) set according to the engine operating conditions. The hydraulic pressure supplied to the advance chamber 42 and the retard chamber 43 of the variable valve timing device 18 is F / B controlled. Here, “F / B” means “feedback” (hereinafter the same). The control region of the VCT phase control extends over the control region of the retard angle mode R, the holding mode H, and the advance angle mode A. Hereinafter, the F / B control executed when the phase control execution condition is satisfied is referred to as “normal phase control”.

  Further, the engine control circuit 21 functions as a lock control means in the claims, and when a lock request is generated when the rotation of the engine 11 is stopped or during idle operation, the VCT phase is temporarily intermediated at that time. The phase control at the time of the lock request for moving to the target phase that has passed the lock phase by a predetermined amount is performed by F / B control such as PD control including at least a proportional term, and then the control duty of the hydraulic control valve 25 is set to the lock mode. The lock pin protrusion control is performed to bias the lock pin 58 in the protrusion direction which is the lock direction while the VCT phase is returned to the intermediate lock phase by setting in the control region, and the VCT phase is intermediately locked by the lock pin 58. Control to lock in phase.

  In this case, in the normal phase control in which the VCT phase is F / B controlled to the target phase set according to the engine operating condition, the phase control response (proportional term) is suppressed so as to suppress overshoot in which the VCT phase greatly exceeds the target phase. If the phase control at the time of the lock request is performed by the F / B control having the same responsiveness as the normal phase control, it takes time to move the VCT phase to the target phase. , It will take longer to complete the lock. In particular, for a lock request that occurs when the engine 11 is stopped, the time until the engine rotation stops (the time required to secure the hydraulic pressure necessary to perform the lock control) is short, so the lock control is performed in a short time. If you do not complete, you will not be able to lock.

  Therefore, in the first embodiment, as shown in FIG. 7, the proportional term gain (hereinafter referred to as “P term gain”) of the phase control at the time of the lock request is set to a larger gain than in the case of the normal phase control. The control duty of the hydraulic control valve 25 when performing phase control at the time of a lock request is set to a control duty that makes the VCT phase move faster than in the case of normal phase control. Alternatively, when performing phase control at the time of lock request, the target phase may be offset in the direction of accelerating the motion of the VCT phase from the target phase (for example, the target phase is retarded from the intermediate lock phase). When setting to the side, the target phase is offset to the retard side). As a result, it is possible to speed up the phase control response at the time of the lock request and shorten the time until the lock is completed.

  By the way, as the responsiveness of the phase control at the time of lock request becomes faster, the overshoot in which the VCT phase passes the target phase by the phase control at the time of lock request increases, so the VCT phase at the start of lock pin protrusion control and the target phase The deviation becomes large, and it takes a long time from the start of lock pin protrusion control to the completion of lock.

  Therefore, in the first embodiment, when the phase control at the time of the lock request is performed, the deviation (absolute value) between the actual VCT phase and the target phase is within a predetermined value K1, and the change speed of the VCT phase to the target phase is a predetermined value. If K2 or more, it is determined that there is no need to speed up the phase control response at the time of lock request, and the P-term gain of phase control at the time of lock request is set to the same gain as the P-term gain of normal phase control Like to do. In this way, it is possible to prevent the responsiveness of the phase control at the time of the lock request from being accelerated excessively, to prevent the overshoot that the VCT phase passes the target phase from becoming too large, and the lock pin can be prevented by an excessive overshoot. It can be prevented that the time from the start of the protrusion control to the completion of the lock becomes too long.

  The lock control of the first embodiment described above is executed by the engine control circuit 21 as follows according to the lock control routine of FIG. The lock control routine of FIG. 6 is repeatedly executed at a predetermined period during engine operation, and serves as a lock control means in the claims. When this routine is started, it is first determined in step 101 whether or not a lock request has occurred. If no lock request has occurred, this routine is terminated without performing the subsequent processing.

  Thereafter, when a lock request is generated, the process proceeds from step 101 to step 102, and phase control at the time of the lock request is started. In the phase control at the time of lock request, the target phase is set to a phase that exceeds the intermediate lock phase by a predetermined amount, and is executed by F / B control such as PD control including at least a proportional term.

  Thereafter, the process proceeds to step 103, in which it is determined whether or not the deviation (absolute value) between the actual VCT phase and the target phase is equal to or greater than a predetermined value K1 or the change rate of the VCT phase to the target phase is equal to or less than a predetermined value K2. If “Yes” is determined in step 103, it is determined that the responsiveness of the phase control at the time of the lock request needs to be accelerated, and the process proceeds to step 104 where the P-term gain of the phase control at the time of the lock request is set to the normal gain. A gain larger than the P-term gain of phase control is set. Alternatively, the target phase may be offset in the direction of accelerating the motion of the VCT phase with respect to the target phase (for example, when the target phase is set to be retarded from the intermediate lock phase, the target phase is delayed). Offset to the corner side). Thereby, it becomes possible to speed up the responsiveness of the phase control when the lock is requested.

  On the other hand, if “No” is determined in step 103, it is determined that it is not necessary to speed up the phase control responsiveness at the time of the lock request, and the process proceeds to step 105, where the P-term gain of the phase control at the time of the lock request is increased. Set to the same gain as the P-term gain for normal phase control. Alternatively, the target phase is set to the original target phase without offsetting the target phase.

  Thereafter, in step 106, it is determined whether or not the actual VCT phase has reached the target phase by phase control at the time of the lock request, and the above-described processing is repeated until the actual VCT phase reaches the target phase, and the lock request is made. Continue phase control of the hour.

  Thereafter, when the actual VCT phase reaches the target phase, the routine proceeds to step 107 and lock pin protrusion control is executed. In this lock pin protrusion control, the control duty of the hydraulic control valve 25 is set in the control region of the lock mode, and the lock pin 58 is attached in the protrusion direction which is the lock direction while returning the VCT phase toward the intermediate lock phase. The lock pin protrusion control is performed, and the lock pin 58 locks the VCT phase at the intermediate lock phase.

  In the first embodiment described above, the P term gain of the phase control at the time of the lock request is set to a gain larger than the P term gain of the normal phase control (or the movement of the VCT phase is larger than the target phase as the target phase). Therefore, the phase control response at the time of the lock request can be accelerated, and the time until the lock is completed can be shortened.

  In addition, when the deviation between the actual VCT phase and the target phase is equal to or less than the predetermined value K1 and the change speed of the VCT phase to the target phase is equal to or greater than the predetermined value K2, there is no need to increase the phase control response at the time of the lock request. Since the P term gain of the phase control at the time of the lock request is set to the same gain as the P term gain of the normal phase control (or the target phase is set to the original target phase), It is possible to prevent excessive acceleration of phase control responsiveness at the time of lock request, prevent excessive overshoot when the VCT phase passes the target phase, and lock complete from the start of lock pin protrusion control due to excessive overshoot. Can be prevented from becoming too long.

  The method for accelerating the phase control responsiveness at the time of the lock request is not limited to the increase of the P term gain or the target phase offset. For example, the phase control F / B control amount is accelerated in the phase control responsiveness. You may make it correct | amend.

  In the second embodiment of the present invention, when the responsiveness of the phase control at the time of the lock request is accelerated by executing the lock control routine of FIG. 8, the phase control at the time of the lock request is executed by the open loop control, The control duty of the open loop control is set to a control duty that makes the VCT phase movement faster than in the case of normal phase control. Other matters are the same as those in the first embodiment.

  Hereinafter, the processing content of the lock control routine of FIG. 8 will be described. When this routine is started, it is first determined in step 201 whether or not a lock request has occurred. If no lock request has occurred, this routine is terminated without performing the subsequent processing.

  Thereafter, when a lock request is generated, the process proceeds from step 201 to step 202, where the deviation (absolute value) between the actual VCT phase and the target phase is a predetermined value K1 or more, or the change rate of the VCT phase to the target phase is a predetermined value. It is determined whether or not K2 or less. If “Yes” is determined in step 202, it is determined that the responsiveness of the phase control at the time of the lock request needs to be accelerated, and the process proceeds to step 203, where the phase control at the time of the lock request is executed by open loop control. At the same time, the control duty of the open loop control is set to a control duty that makes the movement of the VCT phase faster than in the case of normal phase control. Thereby, it becomes possible to speed up the responsiveness of the phase control when the lock is requested.

  On the other hand, if “No” is determined in step 202, it is determined that there is no need to speed up the phase control response at the time of the lock request, and the process proceeds to step 204, where the phase control at the time of the lock request is changed to the normal phase control. The same F / B control is executed.

  Thereafter, in step 205, it is determined whether or not the actual VCT phase has reached the target phase by phase control at the time of the lock request, and the above-described processing is repeated until the actual VCT phase reaches the target phase. Continue phase control of the hour. Thereafter, when the actual VCT phase reaches the target phase, the routine proceeds to step 206, where lock pin protrusion control is executed, and the lock pin 58 locks the VCT phase at the intermediate lock phase.

In the second embodiment described above, the same effect as that of the first embodiment can be obtained.
Note that the present invention is not limited to the first and second embodiments, but is for a VCT phase control hydraulic control valve that controls the hydraulic pressure that drives the VCT phase and a lock control that controls the hydraulic pressure that drives the lock pin 58. It is good also as a structure which provided the hydraulic control valve separately.

  In addition, the first and second embodiments are embodiments in which the present invention is applied to a variable valve timing device for an intake valve, but may be applied to a variable valve timing control device for an exhaust valve. . When the present invention is applied to a variable valve timing control device for an exhaust valve, the control direction of the VCT phase of the exhaust valve (relation between “advance” and “retard”) is opposite to the control direction of the VCT phase of the intake valve. You can do it.

  In addition, it goes without saying that the present invention can be implemented with various modifications within a range not departing from the gist, such as appropriately changing the configuration of the variable valve timing device 18 and the configuration of the hydraulic control valve 25.

  DESCRIPTION OF SYMBOLS 11 ... Engine (internal combustion engine), 12 ... Crankshaft, 13 ... Timing chain, 14, 15 ... Sprocket, 16 ... Intake camshaft, 17 ... Exhaust camshaft, 18 ... Variable valve timing device (VCT), 19 ... Cam angle Sensor 20, crank angle sensor 21, engine control circuit (VCT phase control means, lock control means) 23, coolant temperature sensor 25, hydraulic control valve 28, oil pump 31, housing 35, rotor 40 ... Vane storage chamber, 41 ... Vane, 42 ... Advance chamber, 43 ... Delay chamber, 50 ... Intermediate lock mechanism, 55 ... Spring, 58 ... Lock pin (advance limit pin), 59 ... Lock hole, 63 ... Advance Angle limiting groove, 64 ... retardation limiting pin, 65a, 65b ... retardation limiting groove

Claims (7)

A hydraulically driven variable valve timing device that adjusts the valve timing by changing the rotational phase of the camshaft (hereinafter referred to as “VCT phase”) with respect to the crankshaft of the internal combustion engine, and an intermediate position in which the VCT phase is located within the adjustable range In a variable valve timing control device for an internal combustion engine, comprising: a lock pin that locks in a lock phase; and a hydraulic control valve that controls the variable valve timing device and a hydraulic pressure that drives the lock pin;
Phase control (hereinafter referred to as “normal phase control”) for controlling the hydraulic control valve so that the VCT phase coincides with a target phase set in accordance with operating conditions when a predetermined phase control execution condition is satisfied. VCT phase control means to execute;
When the lock request is generated, the VCT phase is temporarily moved to the target phase that has passed the intermediate lock phase by a predetermined amount. Then, the lock pin protrudes while returning to the intermediate lock phase after performing the phase control at the time of the lock request. Lock control means for performing lock pin protrusion control and controlling the lock pin to lock the VCT phase at the intermediate lock phase,
The variable control valve for an internal combustion engine, wherein the lock control means sets the control amount of the hydraulic control valve to a control amount different from that during the normal phase control when performing phase control at the time of the lock request. Timing control device.   The lock control means sets the control amount of the hydraulic control valve to a control amount that makes the movement of the VCT phase faster than in the case of the normal phase control when performing phase control at the time of the lock request. The variable valve timing control device for an internal combustion engine according to claim 1. The VCT phase control means executes the normal phase control by feedback control including at least a proportional term,
The lock control means executes the phase control at the time of the lock request by feedback control including at least a proportional term, and the gain of the proportional term of the phase control at the time of the lock request is a gain of the proportional term of the normal phase control. The variable valve timing control device for an internal combustion engine according to claim 1 or 2, wherein the gain is set to be larger than that of the internal combustion engine.   The lock control means executes the phase control at the time of the lock request by open loop control, and sets the control amount of the open loop control to a control amount that makes the movement of the VCT phase faster than in the case of the normal phase control. 3. The variable valve timing control device for an internal combustion engine according to claim 1, wherein the variable valve timing control device is set.   5. The lock control unit according to claim 1, wherein when performing the phase control at the time of the lock request, the lock control unit offsets the target phase in a direction of accelerating the movement of the VCT phase from the target phase. A variable valve timing control device for an internal combustion engine according to claim 1.   The lock control means, when performing the phase control at the time of the lock request, when the deviation between the VCT phase and the target phase is within a predetermined value and the change rate of the VCT phase to the target phase is a predetermined value or more. 6. The variable valve timing control device for an internal combustion engine according to claim 1, wherein the control amount of the hydraulic control valve is set to the same control amount as in the case of the normal phase control.   The hydraulic control valve is a hydraulic control valve that integrates a hydraulic control valve function for phase control that controls the hydraulic pressure that drives the VCT phase and a hydraulic control valve function for lock control that controls the hydraulic pressure that drives the lock pin. , And in accordance with the control amount of the hydraulic control valve, the retard mode control region that drives the VCT phase in the retard direction, the hold mode control region that keeps the VCT phase constant, and the VCT phase advance 7. An advance angle mode control region that is driven in a direction and a lock mode control region that biases the lock pin in a protruding direction that is a lock direction. A variable valve timing control device for an internal combustion engine according to claim 1.

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