| 主权项 |
1. A method of controlling a variable valve timing apparatus for an internal combustion engine, the variable valve timing apparatus including: (i) a sprocket-rotor type variable valve timing mechanism, (ii) a spring-actuated phase locking mechanism, (iii) an oil-controlled hydraulic pressure control mechanism, and (iv) an electronic control unit, the method of controlling the variable valve timing apparatus comprising:
in a third operation mode where the engine is operating in a normal operation state:
actuating, by a single control valve, the variable valve timing mechanism in a timing advance direction, the variable valve timing mechanism being configured to change a valve timing of an engine valve between a most advanced timing and a most retarded timing, the single control valve being configured to control a state where working fluid is supplied to or drained from each of an advance chamber of the variable valve timing mechanism, a retard chamber of the variable valve timing mechanism and the phase locking mechanism; andmaintaining a second supply/drain state by supplying working oil to the phase locking mechanism such that the phase locking mechanism is in a release position, the phase locking mechanism being configured to lock the valve timing of the engine valve at an intermediate timing between the most advanced timing and the most retarded timing, the phase locking mechanism being displaced in the release position to unlock the valve timing when: (1) the valve timing is at the intermediate timing, and (2) the working oil supplied or drained by the hydraulic pressure control mechanism is in the second supply/drain state, the hydraulic pressure control mechanism being configured to hydraulically actuate the variable valve timing mechanism and the phase locking mechanism; and in a fourth operation mode where the engine operates at an idle or stopped state, in response to a first amount of working oil supplied to the advance chamber of the variable valve timing mechanism being smaller than a second amount of working oil supplied to the variable valve timing mechanism in the third operation mode:
actuating, by the single control valve, the variable valve timing mechanism in the timing advance direction;maintaining a first supply/drain state by draining working oil from the phase locking mechanism so that the phase locking mechanism is in a lock position, the phase locking mechanism being displaced in the lock position to lock the valve timing when: (1) the valve timing is at the intermediate timing, and (2) a working oil supplied to or drained from the phase locking mechanism by the hydraulic pressure control mechanism is in the first supply/drain state;controlling, by the single control valve, a flow rate of a supply of the first amount of working oil at a lower flow rate in the fourth operation mode than a flow rate in the third operation mode; andactuating, by the single control valve, the variable valve timing mechanism at a lower rotational rate of change in the fourth operation mode than in the third operation mode. |
