Piston ring having a first annular body and a second annular body, which annular bodies, are arranged adjacent to and concentric with one another in the axial direction (A), the first annular body having a radially outwardly directed outer side, an upper and a lower flank and a radially inwardly directed inner side, the second annular body being designed as a segmented sealing ring having a plurality of sealing ring segments, which sealing ring segments each have a radially outwardly directed sealing surface, an up-per and a lower sealing ring segment flank and a radially inwardly directed inner side, the sealing ring segments each being guided on the first annular body by means of at least one guide means, which guide means substantially prevent twisting of the sealing ring segments against the first annular body in the circumferential direction (U) and permit displacement of the sealing ring segments transversely to the axial direction (A).

A split piston ring unit may include a first ring body, a second ring body, and a spacer insert. The first ring body may define a first circumferential gap. The second ring body may define a second circumferential gap. The spacer insert may be coupled to the first ring body and the second ring body. The first ring body and the second ring body may be arranged coaxially and oriented in an offset orientation where the first circumferential gap and the second circumferential gap are disposed circumferentially offset from one another by an offset distance. The spacer insert may be disposed in the offset distance between the first circumferential gap and the second circumferential gap to maintain the offset orientation.

Provided is a piston ring including: a low-pressure side ring; and a high-pressure side ring, the low-pressure side ring and the high-pressure side ring are arranged stacked in a direction along the axis so that the high-pressure side ring is closer to a fluid to be compressed, a low-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston is formed to the low-pressure side ring, a high-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston and a low-pressure side protrusion protruding toward the low-pressure side ring and inserted in the low-pressure side abutment are formed to the high-pressure side ring, and the low-pressure side protrusion is inserted in a low-pressure side abutment with clearances being provided in both sides in the circumferential direction between the low-pressure side ring and the low-pressure side protrusion.

Provided is a piston ring including: a low-pressure side ring; and a high-pressure side ring, the low-pressure side ring and the high-pressure side ring are arranged stacked in a direction along the axis so that the high-pressure side ring is closer to a fluid to be compressed, a low-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston is formed to the low-pressure side ring, a high-pressure side rotation restriction part configured to restrict rotation in the circumferential direction relative to the piston and a low-pressure side protrusion protruding toward the low-pressure side ring and inserted in the low-pressure side abutment are formed to the high-pressure side ring, and the low-pressure side protrusion is inserted in a low-pressure side abutment with clearances being provided in both sides in the circumferential direction between the low-pressure side ring and the low-pressure side protrusion.

In some two-stroke engines, a stationary ring is disposed in a groove in the cylinder liner. However, it is a challenge to install such a stationary ring while maintaining a narrow gap to minimize gas flow through the gap. A ring system for an internal combustion engine is disclosed that includes an L-shaped, split ring with a reentrant angle and a nested, split ring with a convex quadrilateral cross section nested with the L-shaped ring proximate the reentrant angle. The two rings are affixed so that the two gaps of the split rings cannot align. Or, in other embodiments, the two are allowed to rotate relative to each other over a predetermined angle.

In some two-stroke engines, a stationary ring is disposed in a groove in the cylinder liner. However, it is a challenge to install such a stationary ring while maintaining a narrow gap to minimize gas flow through the gap. A ring system for an internal combustion engine is disclosed that includes an L-shaped, split ring with a reentrant angle and a nested, split ring with a convex quadrilateral cross section nested with the L-shaped ring proximate the reentrant angle. The two rings are affixed so that the two gaps of the split rings cannot align. Or, in other embodiments, the two are allowed to rotate relative to each other over a predetermined angle.

A compressor has a piston that has a piston ring groove in an outer circumferential surface formed of a curved surface and reciprocates while rocking in a cylinder, a piston ring that is mounted in the piston ring groove and slides on an inner circumferential surface of the cylinder, and a crankshaft that reciprocates the piston through a connecting rod. A center axis of the cylinder is disposed at a position separate from a rotation axis of the crankshaft. A rotation stopper for the piston ring is disposed in the piston ring groove. Joint gaps of the piston ring are located on a side of the outer circumferential surface of the piston pressed against the inner circumferential surface of the cylinder in a compression process.

A compressor has a piston that has a piston ring groove in an outer circumferential surface formed of a curved surface and reciprocates while rocking in a cylinder, a piston ring that is mounted in the piston ring groove and slides on an inner circumferential surface of the cylinder, and a crankshaft that reciprocates the piston through a connecting rod. A center axis of the cylinder is disposed at a position separate from a rotation axis of the crankshaft. A rotation stopper for the piston ring is disposed in the piston ring groove. Joint gaps of the piston ring are located on a side of the outer circumferential surface of the piston pressed against the inner circumferential surface of the cylinder in a compression process.

A compressor has a piston that has a piston ring groove in an outer circumferential surface formed of a curved surface and reciprocates while rocking in a cylinder, a piston ring that is mounted in the piston ring groove and slides on an inner circumferential surface of the cylinder, and a crankshaft that reciprocates the piston through a connecting rod. A center axis of the cylinder is disposed at a position separate from a rotation axis of the crankshaft. A rotation stopper for the piston ring is disposed in the piston ring groove. Joint gaps of the piston ring are located on a side of the outer circumferential surface of the piston pressed against the inner circumferential surface of the cylinder in a compression process.

A compressor has a piston that has a piston ring groove in an outer circumferential surface formed of a curved surface and reciprocates while rocking in a cylinder, a piston ring that is mounted in the piston ring groove and slides on an inner circumferential surface of the cylinder, and a crankshaft that reciprocates the piston through a connecting rod. A center axis of the cylinder is disposed at a position separate from a rotation axis of the crankshaft. A rotation stopper for the piston ring is disposed in the piston ring groove. Joint gaps of the piston ring are located on a side of the outer circumferential surface of the piston pressed against the inner circumferential surface of the cylinder in a compression process.