| 摘要 |
PROBLEM TO BE SOLVED: To prevent knocking when an engine is operated at a theoretical air-fuel ratio while operating the engine at the theoretical air-fuel ratio in a wide operating area, and to provide a large engine torque beyond a critical torque obtained when the engine is operated at the theoretical air-fuel ratio. SOLUTION: A selector valve 33 for changing a synchronous rotational speed through dynamic supercharging effects is installed in an intake passage. A maximum load line when the engine is operated at the theoretical air-fuel ratio is set in such a manner as to be positioned further on the low torque side than the maximum torque line of the engine. A load area equal to or lower than the maximum load line is a theoretical air-fuel ratio area where a cylinder air-fuel ratio is equal to the theoretical air-fuel ratio. The area between the maximum load line and the maximum torque line is an enrich area where the cylinder air-fuel ratio is richer than the theoretical air-fuel ratio and a torque is increased. The engine is controlled with a controller U so that, in the low speed range of the engine, the dynamic supercharging effects are not synchronized in a high load are within the theoretical air-fuel ratio area, and that the dynamic supercharging effects are synchronized in the enrich area. COPYRIGHT: (C)2010,JPO&INPIT |
