Patent ID: 7769529

Claim:
A variable valve timing apparatus for changing a timing of opening/closing at least one of an intake valve and an exhaust valve provided in an engine, comprising: an actuator operating said variable valve timing apparatus; and a changing mechanism for changing the opening/closing timing, by an amount of change in accordance with an operation amount of said actuator; wherein said changing mechanism is configured to change said opening/closing timing by a first amount of change in accordance with the operation amount of said actuator when said opening/closing timing is in a first region, and to change said opening/closing timing by a second amount of change larger than said first amount of change in accordance with the operation amount of said actuator when said opening/closing timing is in a second region different from said first region; said valve timing apparatus further comprising: reference position learning means configured to generate an actuator operation command so that said opening/closing timing is changed to a prescribed timing within said first region, and when said opening/closing timing reaches said prescribed timing, to learn the reference timing of said opening/closing timing in response; and power supply stopping means for stopping power supply to said actuator when learning of said reference timing by said reference position learning means is completed.