A piston ring system for an internal combustion engine includes a first compression piston ring (2), a second compression piston ring (4), and an oil scraper piston ring (6). The first compression piston ring (2) has a first ring body (8) with a first upper ring flank (10), a first lower ring flank (12), a first ring inner side (14), a first ring outer side (16), as well as two first abutting surfaces. A first contact region (18) of the first ring body (8) is arranged with a cylinder running surface (20) above a first piston ring center (22). At least one first oil pocket (24) is arranged below the first contact region (18) in the circumferential direction. The second compression piston ring (4) having a second ring body (26) a second upper ring flank (28), a second lower ring flank (30), a second ring inner side (32), a second ring outer side (34), as well as two second abutting surfaces. A second contact region (36) of the second ring body (26) is arranged with the cylinder running surface (20) above or below a second piston ring center (38). At least one second oil pocket (40) is arranged below the second contact region (36) in the circumferential direction. The oil scraper piston ring (6) is formed in one piece, two pieces, or three pieces.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

A piston assembly for an internal combustion engine includes a cylinder bore and a piston having a plurality of ring grooves, and a ring positioned within a ring groove. The ring includes a cross-section having a lower surface and an outer radial surface that form a scraping corner, an inner radial surface, and an upper surface. The upper surface and the lower surface are generally parallel with one another, and both upper and lower surfaces form a positive first angle with respect to a radial axis, and the outer radial surface forms a second positive angle with respect to a central axis. A constant twist occurs in the ring about a rotational center of the cross-section, the constant twist occurring at each cross-sectional location of the ring about the circumference of the ring and between adjacent free ends of the ring.

Methods and apparatuses for installing a piston ring onto a piston include a piston ring feeder having at least one projection feature and a receiving aperture. Methods include receiving a piston end having a piston groove into the receiving aperture until the piston groove is above piston rings on the piston ring feeder and below projection feature top ends; raising a ring to partially snap into the piston groove with ring ends separated by a first projection feature and the ring wrapped around a second projection feature; raising the piston such that the ring is pulled off the second projection feature while the first projection feature separates the ring ends; and raising the piston such that the first projection feature releases the ring ends and the ring fully snaps into the piston groove to form a gap between the ring ends of the ring seated in the piston groove.

A gas compressor of the present invention includes a reciprocating member, an accommodation portion, and a sealing portion, and the accommodation portion includes a compression chamber that compresses a gas and a non-compression chamber that is separated from the compression chamber by the reciprocating member and the sealing portion. Further, since the compression chamber includes a suction line that suctions a hydrogen gas, a discharge line that discharges a compressed gas, a connection line that is connected to the accommodation portion and is used so that at least a part of a gas flows therethrough when a gas passing through the sealing portion from the compression chamber exists, a flowmeter that is provided in the connection line, and a determination unit that determines whether a flow amount measured by the flowmeter is equal to or larger than a predetermined threshold value, it is possible to easily determine the abrasion state of the sealing portion.

A gas compressor of the present invention includes a reciprocating member, an accommodation portion, and a sealing portion, and the accommodation portion includes a compression chamber that compresses a gas and a non-compression chamber that is separated from the compression chamber by the reciprocating member and the sealing portion. Further, since the compression chamber includes a suction line that suctions a hydrogen gas, a discharge line that discharges a compressed gas, a connection line that is connected to the accommodation portion and is used so that at least a part of a gas flows therethrough when a gas passing through the sealing portion from the compression chamber exists, a flowmeter that is provided in the connection line, and a determination unit that determines whether a flow amount measured by the flowmeter is equal to or larger than a predetermined threshold value, it is possible to easily determine the abrasion state of the sealing portion.

To provide a combined oil control ring comprising a pair of upper and lower side rails and an axially corrugated spacer expander having upper and lower portions for automobile engines, which is capable of keeping an excellent oil-controlling function without sticking between a spacer expander and side rails even in a long period of engine operation, the upper and lower portions of the spacer expander have tabs pushing inner peripheral surfaces of the side rails, projections supporting the side rails, and intermediate portions between the tabs and the projections; and each intermediate portion opposing the side rail has a center-raised bottom having a center-raised shape when viewed along a substantially circumferential direction center-raised shape and a radial direction.

A method for estimating life of a piston ring includes obtaining a reference profile of the piston ring. The reference profile comprises a plurality of reference fiducials. The method further includes receiving a measured profile of the piston ring. The measured profile comprises a plurality of measured fiducials. The method further includes aligning the measured profile with the reference profile based on one or more of the plurality of reference fiducials and one or more of the plurality of measured fiducials. The method also includes determining one or more wear parameters based on the aligned measured profile and the reference profile. The method also includes generating a wear model based on the one or more wear parameters. The method also includes estimating a life of the piston ring based on the wear model.

A method for producing a piston for internal combustion engines, where the piston includes a circumferential trapezoid annular groove for receiving trapezoid rings with small axial dimensions the groove having a groove base with adjoining surfaces and groove flanks. The groove base with adjoining surfaces is created in a first method step by machining using a cutting steel tool and the groove flanks are created in a further method step. Also disclosed are a piston produced according to the method and a cutting steel tool.

A method for producing a piston for internal combustion engines, where the piston includes a circumferential trapezoid annular groove for receiving trapezoid rings with small axial dimensions the groove having a groove base with adjoining surfaces and groove flanks. The groove base with adjoining surfaces is created in a first method step by machining using a cutting steel tool and the groove flanks are created in a further method step. Also disclosed are a piston produced according to the method and a cutting steel tool.