Abstract: A piston ring assembly includes a ring or rail defining a seal surface configured to seal against a piston bore surface of an engine. The seal surface defines a radially outer periphery. The oil control rail assembly further includes two positioning rings. A first one of the positioning rings is disposed axially above the oil control rail and a second one of the positioning rings is disposed axially below the oil control rail. Each of the positioning rings defines an outermost periphery of the positioning ring that is disposed radially inward with respect to the seal surface of the oil control rail. The outermost peripheries of the positioning rings thus generally do not contact a bore surface that is contacted by the seal surface of the oil control rail.

Abstract: A piston assembly for an internal combustion engine is provided, including a piston and at least one insert. The piston includes an annular recess, a first surface, a ring belt and a skirt. The annular recess is located between the ring belt and the skirt. The insert may include a longitudinal portion and one or more opposing arms. The insert may be configured to be coupled with the piston. The arm(s) may extend laterally from the longitudinal portion and may be configured to abut the skirt, thereby orienting the insert relative to the piston. The insert may be disposed along the first surface, and aligned with the piston skirt such that the arms of the insert form a circumference about the piston skirt. The arms may at least partially enclose the annular recess at the piston skirt.

Abstract: A piston has a body with a first circumferentially disposed groove. A first ring is movably disposed within the first groove. The first ring defines an inner circumferential groove. A blocking ring is at least partially located in the groove of the first ring and the groove of the piston. One or more vent passages may connect a first volume in the piston to a second volume outside the piston.

Abstract: A piston assembly is described including a connecting rod and a piston head secured to the connecting rod and in operational communication with the connecting rod. The piston head has a circumferential groove extending inwardly from an exterior surface of the piston head. The piston head further has a compression mechanism aperture disposed proximate the groove. An oil ring expander is disposed generally within the groove. The expander includes a gap between a first expander end and a second expander end. The gap is proximate the compression mechanism aperture. At least one lever arm is in mechanical communication with the connecting rod. The at least one lever arm has a tab disposed between the first expander end and the second expander end.

Abstract: A piston ring assembly includes an upper ring, a lower ring and an expander disposed between the upper and lower rings. When assembled, the piston ring assembly is positioned with a groove of a piston. During down stroke of the piston, the upper and lower rings radially compress. This radial compression induces axial expansion of the expander, thereby urging the upper and lower rings against upper and lower surfaces of the groove. The piston ring assembly provides a seal between not only an outer periphery and a wall of a cylinder, but also between the piston ring assembly and the annular groove of the piston to prevent escape of oil and gases.

Abstract: A piston ring is positioned in a groove of a piston and has an outer peripheral face. The outer peripheral face is generally tapered to an edge and includes a projection. The projection extends radially outwardly from the outer peripheral face along an upper surface of the piston ring. The projection reduces the gap between the outer peripheral face and a wall of the surrounding cylinder. The gap is typically exposed to combustion gases and the projection reduces the exposed area. Ring collapse is the separation of the outer peripheral face from the wall of the cylinder because of downward pressure forces of the combustion gases. Accordingly, the projection reduces the occurrence of ring collapse.