| 主权项 |
1. A piston for balancing combustion efficiency and smoke generation with NOx production in a direct injection compression ignition internal combustion engine having a cylinder bore of about 175 mm, the piston comprising:
a piston body defining a longitudinal axis extending between a first axial body end and a second axial body end, and including an outer body surface extending between the first and second axial body ends, and a combustion face upon the first axial body end; the combustion face forming a combustion bowl and including a conical inner bowl surface, and a concave outer bowl surface extending from the inner bowl surface to a cylindrical wall surface and having a compound curvature increased in sharpness in a radially outward direction; the combustion face further forming an annular piston rim extending circumferentially around the combustion bowl, and including a planar rim surface, and a convex lip surface transitioning between the rim surface and the wall surface and having an intersection with the wall surface that defines a boundary of the combustion bowl; and the outer bowl surface defining a large radius of curvature adjacent the inner bowl surface, and a medium radius of curvature adjacent the wall surface, and the lip surface defining a small radius of curvature, each in a longitudinal section plane, and the inner bowl, outer bowl, and wall surfaces together contouring the combustion bowl, such that a diameter of the combustion bowl is about 124 mm and a volume of the combustion bowl is about 190 cm3 so as to establish a bowl to bore ratio of about 0.71 and a compression ratio of 15:1 to 17:1 when the piston is installed for service in the internal combustion engine. |
