Patent ID: 9611806
Date: 2017-04-04
CPC Classifications: F02B,F02F,F05C,Y02T

Claim:
1. A piston for an internal combustion engine, the piston comprising: a piston body including a crown portion and a skirt portion, the crown portion being radially centered on a longitudinal axis of the piston, the skirt portion defining a bore that is arranged to receive a pin for connecting the piston to a connecting rod, the crown portion defining a bowl surrounded by a flat crown surface having an annular shape and disposed along a plane, the bowl and the flat crown surface meeting along a circular edge surrounding a rim of the bowl; an annular protrusion disposed within the bowl adjacent to the rim, the annular protrusion having a generally convex shape in cross section, and including an upper, inwardly extending surface and a lower, inwardly extending surface that meet along a convex apex; and an airfoil surface formed in the flat crown surface, the airfoil surface having a concave shape and extending annularly around the rim of the bowl, the airfoil surface including an expanding surface and a converging surface, the expanding surface being disposed between the converging surface and the longitudinal axis of the piston, the expanding surface and the converging surface each being recessed below a plane that contains the flat crown surface along a longitudinal direction that is parallel to the longitudinal axis, the expanding surface sinking away from the plane that contains the flat crown surface along the longitudinal direction as the expanding surface extends away from the longitudinal axis along a radial direction, the radial direction being perpendicular to the longitudinal axis, the converging surface rising toward the plane that contains the flat crown surface along the longitudinal direction as the converging surface extends away from the longitudinal axis along the radial direction, a radius of curvature of the expanding surface being larger than a radius of curvature of the converging surface.