| 摘要 |
PROBLEM TO BE SOLVED: To change an internal EGR rate in a wide range while securing high control responsiveness to the change of an engine load, and to suitably control ignition timing in HCCI combustion.SOLUTION: A control device for an engine (1) includes a VVL (71) for opening an exhaust valve (22) after valve opening timing of an intake valve (21), VVTs (72 and 75) for changing the valve timing of the intake and the exhaust valves, and a PCM (10) for changing the valve timing of the intake valve and the exhaust valve by controlling the VVT. The PCM executes control with the VVT so that the valve close timing of the intake valve is almost coincident with the valve close timing of the exhaust valve in an intake stroke when a requested internal EGR rate is equal to or more than a prescribed value, and a negative overlap period is shortened as the requested internal EGR rate becomes smaller than the prescribed value, and the valve open timing and the valve close timing of the exhaust valve in the intake stroke are delayed.SELECTED DRAWING: Figure 5 |
