| 摘要 |
PROBLEM TO BE SOLVED: To avoid enlargement of a hydraulic pump required for releasing a lock mechanism in an idling state while securing an opportunity of learning for zero point calibration of a second variable valve gear mechanism 6. SOLUTION: The second variable valve gear mechanism for retreating/advancing a center angle phase of valve lift characteristics of an intake valve is hydraulically operated, and is locked in a reference start position on the most retard angle side by the lock mechanism, and the most retard angle control position after releasing of locking is slightly on an advance angle side from the reference start position, and is not locked again during operation. Learning for zero point calibration is performed (step 9) when a control target value of the second variable valve mechanism is in the most advance angle position and it is determined that the actual control position is stable in the most advance angle control position (steps 7, 8). Learning in the most advance angle control position is repeatedly performed every prescribed time (step 10). COPYRIGHT: (C)2010,JPO&INPIT |
