Patent ID: 9482153
Filing Date: 2016-11-01
CPC Classification: F02B,F02F

Claim Text:
1. An opposed piston engine having at least one cylinder with a bore surface and longitudinally-spaced exhaust and intake ports, and a pair of opposed pistons disposed in the cylinder for sliding movement along the bore surface, in which an oil-retaining surface texture pattern in an interface between the pistons and the bore surface extends in a longitudinal direction of the cylinder between a top ring reversal zone where the sliding velocity of a ring mounted to a piston reaches zero when the piston is near a top dead center position and a bottom ring reversal zone where the sliding velocity of the ring reaches zero when the piston is near a bottom dead center position, and in which the surface texture pattern comprises at least one row of separate recesses on the bore surface aligned with a bridge of at least one port.