GASOLINE ENGINE HAVING STRUCTURE IN WHICH MILLER CYCLE OPERATION BY FEEDING EXTRA AIR-FUEL MIXTURE TO CYLINDER IN PREVIOUS STROKE AND OTTO CYCLE OPERATION ARE CHANGEABLE TO EACH OTHER

摘要

PPROBLEM TO BE SOLVED: To provide an engine having a structure in which an Otto cycle which is performed when a large output is required and a Miller cycle operation which is smoothly operated since an output is reduced without losing a pumping loss can be changed over to each other. PSOLUTION: In this gasoline engine having four or more cylinders, a valve (Miller valve) is provided for performing the Miller cycle operation, and the Otto cycle operation and the Miller cycle operation for feeding the extra air-fuel mixture to a cylinder in the previous stroke are changeable to each other. When the maximum output is provided, the engine is operated in the Otto cycle, and the pumping loss is reduced by performing the Miller cycle operation to reduce the output. Since the air-fuel mixture fed from the Miller valve is fed directly to the intake port of a cylinder in the operating stroke just before the cylinder, the blowback of an intake valve is eliminated, and the Miller cycle operation can be smoothly performed. PCOPYRIGHT: (C)2010,JPO&INPIT