| 摘要 |
A variable valve timing control apparatus is constructed so as to supply hydraulic pressure to an unlocking chamber (60) for unlocking a lock pin (58) only from a retarding chamber. In cranking an engine (11), a hydraulic pressure control valve (29) is controlled so as to supply the hydraulic pressure only to an advancing chamber and so as not to apply the hydraulic pressure to the unlocking chamber (60). Thereby the lock pin (58) is prevented from being unlocked in cranking the engine in advance. After that, control current of a solenoid (53) of the hydraulic pressure control valve (29) is switched to hold current (Ih) for holding the position of the camshaft phase at the point of time when a time necessary for enabling to supply the hydraulic pressure sufficient to control the camshaft phase from the completion of cranking to supply the hydraulic pressure equally to the both advancing and retarding chambers. Thereby, the hydraulic pressure is supplied also to the unlocking chamber (60) from the retarding chamber and the lock pin (58) is unlocked. |
