Patent ID: 6129070
Filing Date: 2000-10-10
Classification: F02B,F02F,Y02T

Abstract:
A piston for a cylinder direct injection spark ignition internal combustion engine, comprising:a piston head including a protruded section which is protruded from a standard horizontal plane which is perpendicular to a center axis of said piston, said protruded section having a cavity whose periphery forms a generally circular ridgeline, and an inclined surface formed outside said ridgeline and extending toward a periphery of said piston head, said inclined surface continuously sloping down in a direction from said ridgeline to the periphery of said piston, said inclined surface forming an angle (.theta.1) ranging from 10 to 60.degree. relative to said standard horizontal plane,wherein said cavity has a depth (A) within a range of from 3 to 9 mm, said depth being an axial distance between a bottom surface of said cavity and said standard horizontal plane of said piston,wherein said cavity is defined by a generally annular side wall surface, said side wall surface being represented by first and second opposite curved line segments on a vertical plane containing a center axis of said piston and a center axis of said cavity, said first curved line segment being located closer to a spark plug than said second curved line segment, said first curved line segment having a radius of curvature, ranging from 5 to 20 mm.