A piston ring assembly includes an inner ring, a first outer ring, and a second outer ring. The inner ring has an outer surface and an inner surface that extends between a first inner ring face and a second inner ring face. The first outer ring has a first outer ring outer surface disposed opposite a first outer ring inner surface, each extends between a first outer ring face and a first outer ring second face. The first outer ring inner surface engages the outer surface. The second outer ring has a second outer ring outer surface disposed opposite a second outer ring inner surface, each extends between a second outer ring first face and a second outer ring second face.

A piston ring assembly includes an inner ring, a first outer ring, and a second outer ring. The inner ring has an outer surface and an inner surface that extends between a first inner ring face and a second inner ring face. The first outer ring has a first outer ring outer surface disposed opposite a first outer ring inner surface, each extends between a first outer ring face and a first outer ring second face. The first outer ring inner surface engages the outer surface. The second outer ring has a second outer ring outer surface disposed opposite a second outer ring inner surface, each extends between a second outer ring first face and a second outer ring second face.

The invention relates to a component having a coating containing chromium, nitrogen and carbon. According to the invention the coating comprises a sliding layer having a ceramic phase and a carbon phase, the ceramic phase forms a crystalline ceramic phase from Crx(C.sub.1-yN.sub.y) with 0.8=x=1.2 and y>0.7, and the crystalline ceramic phase and the carbon phase form a layer system of alternating individual layers (A, B), wherein the carbon phase has interstices that are filled with the crystalline ceramic phase.

The invention relates to a component having a coating containing chromium, nitrogen and carbon. According to the invention the coating comprises a sliding layer having a ceramic phase and a carbon phase, the ceramic phase forms a crystalline ceramic phase from Crx(C.sub.1-yN.sub.y) with 0.8=x=1.2 and y>0.7, and the crystalline ceramic phase and the carbon phase form a layer system of alternating individual layers (A, B), wherein the carbon phase has interstices that are filled with the crystalline ceramic phase.

A combined oil control ring comprising a pair of annular side rails each having a gap, and an axially corrugated spacer expander arranged between the side rails; the corrugated spacer expander having on the inside seating tabs for pushing inner peripheral surfaces of the side rails; the side-rail-pushing surface of each seating tab being provided with a nitrided layer; an entire surface of each spacer expander except for those provided with the nitrided layer being coated with a plating film; and the plating film having Vickers hardness HV0.01 of 300 or less.

A combined oil control ring comprising a pair of annular side rails each having a gap, and an axially corrugated spacer expander arranged between the side rails; the corrugated spacer expander having on the inside seating tabs for pushing inner peripheral surfaces of the side rails; the side-rail-pushing surface of each seating tab being provided with a nitrided layer; an entire surface of each spacer expander except for those provided with the nitrided layer being coated with a plating film; and the plating film having Vickers hardness HV0.01 of 300 or less.

A scraper ring for a piston includes a top surface, a bottom surface, an inner surface, and an outer surface. The top surface has a first planar portion and a first angled portion. The bottom surface has a second planar portion and a second angled portion. The second angled portion is configured to slidably contact the first angled portion to adjust a diameter of the scraper ring. The inner surface connects the top surface to the bottom surface. The outer surface is opposite to the top surface and is configured to form 360 degrees of contact with a wall of a cylinder to substantially limit an amount of oil entering a combustion chamber of the cylinder.

A scraper ring for a piston includes a top surface, a bottom surface, an inner surface, and an outer surface. The top surface has a first planar portion and a first angled portion. The bottom surface has a second planar portion and a second angled portion. The second angled portion is configured to slidably contact the first angled portion to adjust a diameter of the scraper ring. The inner surface connects the top surface to the bottom surface. The outer surface is opposite to the top surface and is configured to form 360 degrees of contact with a wall of a cylinder to substantially limit an amount of oil entering a combustion chamber of the cylinder.

A piston ring and a method of forming a piston ring. A masking agent is applied to a selective area on an exterior surface of a piston ring. The masking agent inhibits the subsequent application of additional coatings to the selective area on the exterior surface of the piston ring. In one form, the masking agent may inhibit the subsequent application of a nitride layer to the selective area on the exterior surface of the piston ring. A recess may be formed in an outer peripheral side of the piston ring, and a thermal spray coating may be formed within the recess in the outer peripheral side of the piston ring.

A piston ring and a method of forming a piston ring. A masking agent is applied to a selective area on an exterior surface of a piston ring. The masking agent inhibits the subsequent application of additional coatings to the selective area on the exterior surface of the piston ring. In one form, the masking agent may inhibit the subsequent application of a nitride layer to the selective area on the exterior surface of the piston ring. A recess may be formed in an outer peripheral side of the piston ring, and a thermal spray coating may be formed within the recess in the outer peripheral side of the piston ring.