| 摘要 |
PROBLEM TO BE SOLVED: To improve responsiveness related to a change in an internal EGR gas rate and thereby improve responsiveness related to a change in an engine operating state.SOLUTION: If an operating state of an engine body (engine 1) is in a predetermined region for requiring a high cylinder internal temperature, then an intake valve drive mechanism (VVL 71) drives an intake valve 21 in a first mode for performing preceding valve opening 211 of turning the intake valve 21 into an open state in the last half of an expansion stroke and main valve opening 212 of turning the intake valve 21 into an open state in an intake stroke, and an exhaust valve drive mechanism (VVT 74) opens an exhaust valve 22 to be delayed behind the preceding valve opening 211 of the intake valve 21 and drives the exhaust valve 22 to be opened/closed in a first state of opening the exhaust valve 22 so as to introduce part of exhaust gas in an exhaust port 17 into a cylinder in the intake stroke. If the operating state of the engine body is in a region for requiring a lower cylinder internal temperature than that required in the predetermined region, then the intake valve drive mechanism (VVL 71) drives the intake valve 21 in a second mode for not performing the preceding valve opening 211, and the exhaust valve drive mechanism (VVT 74) drives the exhaust valve 22 to be opened/closed in a second state of closing the exhaust valve 22 at advance timing from closing timing in the first state. |
