Gasoline engine of four-cycle ignition type

摘要

An internal combustion engine in which a cylinder head is formed with a pocket and a main piston is formed with an auxiliary piston slidable in the pocket. A combustion chamber is defined between the cylinder head and the main piston. The combustion chamber includes first and second combustion spaces defined between the pocket and the auxiliary piston and between the cylinder head and the main piston when the piston is substantially at a position near a top dead center of a piston stroke. Homogeneous air-fuel mixtures are compressed in the first and second combustion spaces and are ignited by first and second spark plugs disposed in the first and second combustion spaces, respectively, at different times, such that the combustions will be effected at different flame propagation speeds.