Patent ID: 6035823
Filing Date: 2000-03-14
Classification: F02B,F02F,Y02T

Abstract:
A spark-ignition engine comprising:a cylinder head;a spark plug arranged at a central portion of an inner wall of the cylinder head;a fuel injector having a nozzle bore and arranged at a peripheral portion of the inner wall of the cylinder head; anda piston having a cavity formed on a top face thereof,said cavity extending from a position beneath the nozzle bore to a position beneath the spark plug,said cavity having an arc-shaped circumferential wall which extends archwise laterally with respect to a plane including the nozzle bore and an axis of a cylinder, said arc-shaped circumferential wail extending symmetrically with respect to said plane, a radius of curvature of said arc-shaped circumferential wall being not larger than a distance between said nozzle bore and said arc-shaped circumferential wall in said plane, said arc-shaped circumferential wall being inclined with respect to the axis of the cylinder so that an upper portion thereof projects toward a central portion of the cavity,a fuel spray being injected from the nozzle bore toward a bottom wall of the cavity when the engine is operating under a light load,said fuel spray having a shape which is flat when viewed from a direction perpendicular to said plane and is a sector shape when viewed from a direction along the axis of the cylinder.