Patent ID: 8601996

Claim:
A single-piece piston body for an internal combustion engine, comprising: a crown portion having a circumferential ring belt and a bottom wall, the circumferential ring belt including an oil ring groove that is configured to accommodate an oil control ring, the crown portion at least partly defining an annular cooling gallery; a skirt portion having a first skirt wall disposed on a major thrust side of the piston and a second skirt wall disposed on a minor thrust side of the piston, and two box walls that connect the skirt walls and which are set back with respect to the ring belt; a first plurality of drain passages and a second plurality of drain passages, extending from the oil ring groove to the bottom wall of the crown portion, being substantially centered at opposite box sides of the piston, and spanning an arcuate portion of about 45-75 degrees; and a cover plate at least partially covering the annular cooling gallery, the cover plate defining at least one opening therethrough, the at least one opening at least partially overlapping an aperture of one of the plurality of axial drain passages in a circumferential direction about the oil ring groove.