| 摘要 |
PROBLEM TO BE SOLVED: To prevent intake and exhaust valves, which are driven by electromagnetic drive valves within a single cylinder, from operating out-of-synchronism with each other by, when control of opening and closing of the intake and exhaust valves is shifted to a normal control phase of opening and closing of the valves in synchronism with a crank angle after a control phase of keeping all intake and exhaust valves closed, starting the normal control phase with the opening of the exhaust valves. SOLUTION: When an internal combustion engine is started, electromagnetic drive valves 38, 40 are operated to keep all intake valves 42 and exhaust valves 44 of a single cylinder in their fully-closed position and the pressure inside a combustion chamber 26 (in-cylinder pressure) is fluctuated by a vertical movement of a piston 18. Control is then shifted to a normal phase, in which the intake valves 42 and exhaust valves 44 are opened and closed in synchronism with a crank angleθ. If the control is started at this time to open the intake valves 42 first, a force is required that overcomes a high in-cylinder pressure, which could decrease a displacement amplitude of the intake valves 42, resulting in out-of-synchronism. When the normal control is initiated, therefore, the exhaust valves 44 are first opened through an entire exhaust stroke and the intake valves 42 are thereafter opened without a condition of out-of- synchronism.
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