| 摘要 |
PROBLEM TO BE SOLVED: To provide an engine valve gear which can satisfactorily adjust the amount of an internal EGR gas in a transition operation.SOLUTION: The engine valve gear 1A includes a variable valve gear mechanism 57A which can individually change an opening period and a closing period of an intake valve 54 provided in a combustion chamber E of an engine 50A at a constant lift amount. The engine valve gear individually changes the valve closing period of the intake valve 54 depending on an actual EGR ratio and a target EGR ratio so that separation between the actual EGR ratio, which is an actual value of the EGR ratio and the target EGR ratio, which is a target value in the transition operation of the engine 50A. More specifically, when the actual EGR ratio is larger than the target EGR ratio, the valve closing period is individually delayed, and when the actual EGR ratio is smaller than the target EGR ratio, the valve opening period is individually advanced. |
