| 摘要 |
PROBLEM TO BE SOLVED: To further effectively enhance the thermal efficiency of an engine by allowing compression self-ignition combustion under a lean air-fuel ratio to be performed in a wider load range while dispensing with operation for forcibly increasing or decreasing the temperature of fresh air. SOLUTION: In the engine with a supercharger, a geometric compression ratio is set to 16 or more and compression self-ignition combustion under an air-fuel ratio leaner than the theoretical air-fuel ratio is allowed to be performed at least in a low engine speed range. On a lower load side than a given load within an operation range in which the compression self-ignition combustion is performed, an effective compression ratioε' is increased while a fresh air amount is reduced relatively, and on a higher load side than the given load, the effective compression ratioε' is decreased while a fresh air amount is increased relatively by raising a supercharging pressure with a supercharger 25. COPYRIGHT: (C)2011,JPO&INPIT |
