| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To prevent malfunction by surely detecting the occurrence of unintended lock in a lock position during control to a target angle with respect to a variable valve timing mechanism having the lock position between the most advanced angle position and the most retarded angle position. <P>SOLUTION: A valve timing control device checks whether unfollowable flag indicating the occurrence of unintended lock during control to a target angle is set when the device is in a normal F/B mode and a lock position is between a target angle and current angle (S6). When the unfollowable flag is set and when oil temperature is higher than (A) and engine rotation speed is less than B, the determination is made that the lock occurs due to oil pressure drop and oil pressure drop lock control (S9) is executed. When the oil temperature is not higher than (A) or engine rotation speed is not less than B, the determination is made that the lock occurs due to malfunction and malfunction control is executed (S11). Thus, the occurrence of unintended lock to the lock position during control to the target angle can be surely detected, preventing malfunction. <P>COPYRIGHT: (C)2011,JPO&INPIT</p> |
