Patent ID: 6173690
Filing Date: 2001-01-16
Classification: F02B,F02F,Y02T

Abstract:
An in-cylinder direct-injection spark-ignition engine comprising:a cylinder block having a cylinder;a piston movable through a stroke in the cylinder;a cylinder head on said piston;a pentroof combustion chamber recessed in a bottom of said cylinder head and having first and second shallow-angled surfaces;a pair of intake valves disposed in the first shallow-angled surface of said pentroof combustion chamber;a pair of exhaust valves disposed in the second shallow-angled surface of said pentroof combustion chamber;a pair of substantially straight intake ports, in which said pair of intake valves operate, formed in said cylinder head;an intake-air control valve disposed in a first intake port (8a) of said pair of substantially straight intake ports for adjusting an amount of intake air passing through the first intake port;a spark plug installed in said cylinder head in a substantially center of the cylinder;a fuel injector disposed in the bottom of said cylinder head adjacent to said pair of intake valves so that an axial line of said fuel injector is directed to the substantially center of the cylinder, for injecting fuel directly into the cylinder; anda control unit being configured to be electronically connected to said fuel injector for switching between a homogeneous combustion mode where early fuel-injection on intake stroke produces a homogeneous air-fuel mixture while producing a tumbling action into the cylinder, and a stratified combustion mode where late fuel-injection on compression stroke produces a stratified air-fuel mixture while producing a swirling action into the cylinder;wherein a piston crown of said piston comprises an intake-valve side inclined surface (22) generally parallel to the first shallow-angled surface (11a), an exhaust-valve side inclined surface (23) generally parallel to the second shallow-angled surface (11b), and a piston bowl (12) having a substantially round opening (12a) and arranged in an eccentric position with respect to an outside circle of an upper portion of said piston toward said pair of intake valves, andwherein said piston bowl has a deeply-recessed bowl cavity (31), and the deeply-recessed bowl cavity (31) is arranged eccentrically to the opening of the piston bowl toward a second intake port (8b) of said pair of substantially straight intake ports.