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

摘要

A piston (18) for a compression ignition internal combustion engine (10) includes a piston body (20) having a combustion face (28) defining a combustion bowl (30), and the combustion face (28) including a compound bowl surface (32) and a compound rim surface (38). The combustion face (28) is profiled to balance a combustion efficiency property of the piston (18) with emissions properties of the piston (18), and includes a profile of rotation defining a convex curve segment (110) bisected by the longitudinal axis, and a plurality of concave curve segments (112) outboard of the convex curve segment (110). The profile of rotation further includes a compound rim profile defining a plurality of convex curve segments (116) corresponding to an inner rim surface (42). The convex curve segment (110) of the compound bowl profile defines a relatively small radius of curvature, and the plurality of convex curve segments (116) corresponding to the inner rim surface (42) define a relatively large radius of curvature. The combustion face (28) includes an abrupt transition (48) from the compound bowl surface (32) to the compound rim surface (38).