| 摘要 |
PROBLEM TO BE SOLVED: To improve fuel economy by reducing the occurrence of a pumping loss in low rotation low load operation including an idling time. SOLUTION: A valve system control device comprises a phase varying mechanism to vary the switching timings of a suction valve and an exhaust valve; and a lift varying mechanism capable of respectively varying lift amounts of the two suction valves and the phase varying mechanisms of each of cylinders. A lift varying mechanism of the second suction valves of the two suction valves of each cylinder is substantially stopped. Control is effected such that in a low rotation low load operation area, the opening timing of a first suction valve is delayed by IO from a suction top dead center, the substantial suction stop of a second suction valve is stopped, and the closing timing of the exhaust valve is advanced by EC from a suction top bead center. Further, a relation of IO and EC is set to IO<EC, an exhaust process is completed slightly in a compression state, and in a suction stroke, a piston is pushed back, the occurrence of a pumping loss is reduced, and combustion is improved by a swirl effect. COPYRIGHT: (C)2004,JPO
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