| 摘要 |
PROBLEM TO BE SOLVED: To overcome problems that conventionally, the reference position offset diagnosis of a variable valve timing mechanism is executed when prescribed time has passed after being in an idle operating state not requiring engine torque, the idle operating state hardly exists and sufficient learning time or diagnosis time cannot be secured in a vehicle which stops idling or a hybrid vehicle which is driven by an internal combustion engine and an electric motor, and there is a method for prohibiting shifting to idle-stop and performing diagnosis, but concerns about influence on fuel economy may be raised when the time for stopping the engine is delayed for the prescribed time.SOLUTION: The reference position offset diagnosis is executed in a lock mechanism restricting state in starting of the engine. In addition to the ordinary reference position offset diagnosis executed after a valve timing control start condition is established, the diagnosis is also executed before the valve timing control start condition is established, and thereby, a diagnosis frequency can be increased. |
