Patent ID: 8356550

Claim:
A piston ( 20 ) for an internal combustion engine comprising: a piston body ( 22 ) extending along a longitudinal axis (L) having a pair of pin bosses ( 36 ) with pin bores ( 38 ) aligned along a pin bore axis (P) that is transverse to said longitudinal axis (L), and a piston skirt ( 30 ) having an outer surface ( 42 ) with a convex profile in the circumferential direction of said piston skirt ( 30 ); said outer surface ( 42 ) of said piston skirt ( 30 ) including at least one oil reservoir ( 44 ) disposed above said pin bore axis (P) and at least one oil recess ( 46 ) disposed below said pin bore axis (P) and spaced longitudinally from said at least one oil reservoir ( 44 ) by an intervening oil spreading area ( 48 ) of said piston skirt ( 30 ); and wherein said at least one oil reservoir ( 44 ) and said at least one oil recess ( 46 ) have radiused corners ( 54 ) or edges at a transition between said outer surface ( 42 ) of said piston skirt ( 30 ) and at a bottom ( 50 ) of said at least one oil reservoir ( 44 ) and said at least one oil recess ( 46 ), such that said at least one oil reservoir ( 44 ) and said at least one oil recess ( 46 ) are free of sharp edges or corners.