Piston having combustion bowl shaped to balance combustion efficiency and emission properties

摘要

A piston for an internal combustion engine includes a piston body having an outer cylindrical surface defining a longitudinal piston axis, a combustion face defining a compound combustion bowl, and a compound rim extending radially outward from the compound combustion bowl to the outer cylindrical surface. The compound combustion bowl includes a convex inner bowl surface defining a conical projection and a concave outer bowl surface. The compound rim includes a flat outer rim surface adjoining the outer cylindrical surface, and a convex inner rim surface adjoining the compound combustion bowl. The convex inner bowl surface transitions smoothly to the concave outer bowl surface, and the convex inner rim surface transitions abruptly to the concave outer bowl surface at an edge of the compound combustion bowl.