Abstract: A direct cylinder injection-type spark ignition internal combustion engine is disclosed. The internal combustion engine comprises a spark plug 6, a cavity 8 formed in the top surface of the piston, and a fuel injection valve 7 for injecting fuel into said cavity in nearly the shape of a fan having a relative small thickness. A side wall 8b of the cavity opposed to the fuel injection valve for leading the fuel to the vicinity of the spark plug, has a horizontal arcuate shape which is nearly symmetrical to a first vertical plane (N1). The first vertical plane is separated away from a vertical center plane (Nc) at the center of the fuel and is nearly parallel with the vertical center plane.

Abstract: A spark-ignition type engine comprising a spark plug arranged at the center of the inner wall of the cylinder head and a fuel injector arranged at the periphery of the inner wall of the cylinder head. A cavity extending from a position beneath the fuel injector to a position beneath the spark plug is formed on the top face of the piston. The circumferential wall of the cavity extends archwise below the spark plug and has an arc shaped cross section.