Patent ID: 7690348

Claim:
A direct-injection spark-ignition internal combustion engine, comprising: a combustion chamber defined by an undersurface of a cylinder head, a cylinder and a top face of a piston, a cavity of a concave shape formed in the top face of the piston, the cavity having a bottom surface that slopes downward, from a first end to a second end opposite to the first end, and a wall surface that slopes upward from the periphery of the bottom surface, an injector fitted to the undersurface of the cylinder head, on said first-end side, for injecting fuel directly into the combustion chamber, and a spark plug fitted to the undersurface of the cylinder head, on said second-end side, with an electrode part located within or near a fuel injection area in which fuel is injected by the injector, the spark plug being capable of igniting fuel spray during fuel injection and then igniting fuel spray that is guided along the bottom surface of the cavity and curls up along the wall surface, wherein said bottom surface has a raised part higher than a part around, the raised part extending from near the center of the bottom surface to said first end.