Abstract: Unique apparatuses and methods for scraping deposits from a piston as the piston moves in an upstroke direction and a downstroke direction. An engine assembly includes a cylinder having a cylinder bore, a piston having a crown end, wherein the piston is disposed in the cylinder bore and configured to move in an upstroke direction and a downstroke direction relative to the cylinder bore. The piston includes a first land positioned adjacent the crown end. An antipolishing ring is disposed within the cylinder bore. The antipolishing ring has an outer annular surface and an inner annular surface, the inner annular surface has one or more protrusions configured to scrape the first land when the piston moves in the upstroke direction and the downstroke direction. The protrusions are also configured to scrape the first land when the piston has secondary or lateral motion.

Abstract: Provided are an oil ring for an internal combustion engine and a piston assembly including the same, in which the oil ring for an internal combustion engine includes: a compression portion protruding from an upper portion of a body, in close contact with a cylinder inner wall and effectively limiting explosive gas generated in a combustion chamber; a scraper portion protruding from a lower portion of the body, in close contact with the cylinder inner wall and including a nose scraping off oil oversupplied to cylinder inner wall; and an oil suction portion being a space formed between the compression portion and the scraper portion to collect and discharge the oil oversupplied to cylinder inner wall, thereby reducing leakage of high-temperature and high-pressure gas generated in the combustion chamber, and preventing incomplete combustion caused by oil leaked into the combustion chamber.

Abstract: The present disclosure provides an open-faced piston with a circumferential groove into which a piston ring assembly is arranged. Openings at the bottom of the circumferential groove and between a front land of the open-faced piston and the piston face are provided. The openings are arranged to allow for a combustion reaction to propagate through the volume defined between the bottom of the piston ring assembly and the piston face such that at least a portion of an air and fuel mixture located in that volume is reacted.

Abstract: A side rail (1) in a sprit ring shape is to be mounted on a space expander (2) and to constitute, together with the space expander (2), a multi-piece oil ring (3) used in an internal combustion engine. The side rail (1) includes an outer peripheral surface (14) facing radially outward, an inner peripheral surface (13) facing radially inward, a first axial surface (11) facing one end of an axial direction, and a second axial surface (12) facing the other end of the axial direction and parallel to the first axial surface (11). A bevelled portion (30) is provided between the outer peripheral surface (14) and the second axial surface (12) and formed in a tapered surface having a diameter gradually decreasing from a position on the outer peripheral surface (14) at 0.05 mm or more from the first axial surface (11) toward the second axial surface (12).

Abstract: The present disclosure provides an open-faced piston with a circumferential groove into which a piston ring assembly is arranged. Openings at the bottom of the circumferential groove and between a front land of the open-faced piston and the piston face are provided. The openings are arranged to allow for a combustion reaction to propagate through the volume defined between the bottom of the piston ring assembly and the piston face such that at least a portion of an air and fuel mixture located in that volume is reacted.

Abstract: A single-piece oil control ring for a piston may include a body having at least one upper portion and at least one lower portion each facing towards a cylinder wall of an internal combustion engine. At least one of the upper portion and the lower portion may respectively define a first surface extending substantially perpendicular to the body and a receding second surface extending from the first surface substantially at an incline. The first surface may protrude towards the cylinder wall in relation to the second surface. The first surface may have a first area of contact with the cylinder wall, and at least 95% of the first area may contact the cylinder wall.

Abstract: An oil ring for an internal combustion engine is provided that can prevent adhesion and deposition of oil sludge even during long-time operation of the engine, can thereby prevent the occurrence of sticking of the oil ring components to each other, and can maintain a good oil control function. At least part of the surface of the oil ring for an internal combustion engine is coated with a metal coating having a surface free energy of 40 mJ/m2 or less and a hydrogen bonding strength of 1.0 mJ/m2 or less. A coating of Ni, Cu, or an alloy containing Ni or Cu is used as the metal coating.

Abstract: In an annular groove carried by one of a pair of reciprocally movable members, a piston ring is carried by the annular groove for sealing the reciprocally movable members for minimizing fluid leakage between the members. The piston ring is an annular member that includes an outer contact surface engagable with the sidewall, an opposed inner surface, an end gap that severs the annular member and that defines spaced-apart first and second ends of the annular member, and annular member tension-relieving notches formed in the inner surface of the annular member. The notches are spaced-apart along the length of the annular member between the first end and the second end, and each notch has a blunt notch tip for inhibiting crack propagation in the annular member from said blunt notch tip when the annular member is tensioned.

Abstract: A multi-piece oil ring is provided in which, even after long-term operation of an engine, adhesion and deposition of oil sludge are prevented, sticking of components does not occur, and a high oil control function can be maintained. The multi-piece oil ring includes a spacer expander and a pair of upper and lower side rails supported by the spacer expander. To achieve the above features, at least side faces of the side rails that face the spacer expander are coated with a fluorine-containing coating, and the spacer expander is coated with a metal coating. The angle of contact (?1) of a paraffin-based lubricating oil with the portions of the side rails at 150° C. that are coated with the fluorine-containing coating is 50° or larger, and the angle of contact (?2) of the paraffin-based lubricating oil with the portion of the spacer expander at 150° C. that is coated with the metal coating is 10 to 50°. The difference between ?1 and ?2 (?1??2) is 30° or larger.

Abstract: A piston for an internal combustion engine includes a piston crown (2) and a cylindrical side wall (4), an annular piston ring groove (8) being formed in the side wall (4) which accommodates an annular spring (14). The spring (14) includes an annular radially extending portion (16) and first (20) and second (22) projections. The radially extending portion (16) divides the annular groove into two chambers in the axial direction of the piston. The upper chamber closest to the piston crown accommodates an annular compression ring (10). The lower chamber furthest from the piston crown accommodates an annular oil scraper ring (12). The first projection (20) is arranged to contact the upper surface closest to the piston crown of the annular groove (8). The second projection (22) is arranged to contact the inner surface of the oil scraper ring (12) to urge it outwardly.

Abstract: A ring assembly, including a first oil scraper ring, a center oil scraper ring and a gas seal ring, adapted for disposition in a single groove of a packing cup which can be stationarily mounted over and around a reciprocally movable piston rod of a gas compressor. The function of the assembly is to both scrape lubricating oil from the piston rod for return to one side of the cup and to provide a seal against gas leakage from an opposite side of the cup, both along the piston rod under the seal ring and between the seal ring and opposing sides of the center ring and groove to prevent mixing of gas with the oil and escape of gas from the compressor. The center ring features a tapered outer peripheral surface portion. An annular side loading element, which can be a garter spring, is mounted in compression around the center ring so as to bear against the tapered surface portion and against an adjacent side of the first ring.