| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a variable valve system for improving exhaust emission performance and startability by reducing the amount of residing gas in a cylinder at starting an engine. <P>SOLUTION: The variable valve system comprises an exhaust VEL 1 for variably controlling the operating angle of an exhaust valve depending on the operating condition of the engine, an exhaust VTC 2 for variably controlling an opening/closing timing for the exhaust valve, and an intake VTC 3 for variably controlling the operating angle of an intake valve. At stopping the engine (at the beginning of start), the exhaust VEL 1 holds the exhaust valve at a small operating angle-lift and the exhaust VTC 2 holds it on the maximum-delay angle side with the spring force of a coil spring so that a closing timing (EVC 1) for the exhaust valve is held at a position sufficiently close to the bottom dead center of a piston, namely, at a position θEVC 1 somewhat delayed from the top dead center. Additionally, the intake VTC 3 holds an opening/closing timing for the intake valve on the maximum-advance angle side with the spring force of the coil spring. <P>COPYRIGHT: (C)2009,JPO&INPIT |
