A piston ring includes a plurality of first ring pieces placed inside the ring groove in a stacking manner such that the first ring pieces adhere to each other in the axis direction. The first ring pieces include respective piston ring gap portions each having end surfaces separated from each other in the circumferential direction of the first ring pieces such that the end surfaces face each other via a ring gap having a predetermined dimension. The respective piston ring gap portions of the first ring pieces are displaced from each other in the circumferential direction. A closing member is provided to close the piston ring gap portions of the first ring pieces in the radial direction of the first ring pieces.

A piston ring configured to be disposed in a floating piston for use in a vessel of a thermal energy storage system to separate a hot working fluid from a cold working fluid, wherein the piston ring comprises of a plurality of arc segments, each arc segment interconnected by a joint.

A piston ring has an annular base body 2, which is preferably open at a joint, with a U-shaped cross section, the open side of which faces inwards in the radial direction. A ring spring 4 is provided which runs in a meandering manner in the axial direction, and which pretensions the base body 2 outwards in the radial direction. In one section of the ring spring 4, which is located inside the base body, meandering loops 5 bear alternately against the shanks 3 of the U-shaped cross section. In one section of the ring spring 4, which protrudes out of the base body 2, meandering loops 6 bear alternately against the radially inwardly facing edges of the shanks 3 of the U-shaped cross section.

A three-piece oil ring for an internal combustion engine may include an expanding element defining at least a first side and a second side opposite the first side. A first upper annular segment may be associated with the first side of the expanding element. A second lower annular segment may be associated with the second side of the expanding element. The first annular segment and the second annular segment may each include a first internal side surface and a second external side surface. A metallic tungsten matrix coating may be disposed on at least one of the expanding element, the first annular segment and the second annular segment via chemical vapor deposition. The coating may contain a tungsten nanocarbide that may include at least one of WC, W2C, W3C and W12C. The coating may include a thickness between 5 μm and 150 μm and a hardness between 1000HV and 3500HV.

The piston ring unit includes a plurality of piston rings and an inner contact ring. A plurality of piston rings are disposed adjacent to each other in an axial direction of the piston such that joints of plurality of the piston rings do not overlap with each other in the axial direction. An inner contact ring is interposed between an outer circumferential surface of the piston and an inner circumferential surface of the piston ring in a state where the inner contact ring extends over all of the plurality of piston rings in the axial direction, and is disposed such that an opening of the inner contact ring does not overlap with the joint of the at least one piston ring as viewed in a radial direction of the piston.

Systems and methods are provided for a cantilever beam arrangement that preloads ring segments in a multi0segment piston ring arrangement. A piston assembly comprises a piston that comprises a land. A ring segment is arranged against the land. The ring segment comprises a radially inner surface, a radially outer surface for sealing against a bore, and a boss located on the radially inner surface. The piston assembly also includes a beam spring having a proximal end attached to the piston and a distal end in contact with the boss. The beam spring forces at least a portion of the ring segment radially outward by applying a force on the boss.

A fuel pump for an internal combustion engine comprising a barrel having a longitudinal axis that spans between a proximal end and a distal end and a central bore therein. A plunger is disposed at least partially in the central bore and is configured to move along the longitudinal axis. An annular seal assembly is arranged around the circumference of the plunger wherein the annular seal assembly includes a seal retainer housing and a first seal and the seal retainer housing also retains the proximal end of the barrel thereon to form a second seal wherein the first and the second seals reduce the fuel to oil transfer rate and the oil to fuel transfer rate. The plunger and barrel are configured to be removed from and re-assembled with the annular seal assembly to enable service of these parts and the fuel pump.

A fuel pump for an internal combustion engine comprising a barrel having a longitudinal axis that spans between a proximal end and a distal end and a central bore therein. A plunger is disposed at least partially in the central bore and is configured to move along the longitudinal axis. An annular seal assembly is arranged around the circumference of the plunger wherein the annular seal assembly includes a seal retainer housing and a first seal and the seal retainer housing also retains the proximal end of the barrel thereon to form a second seal wherein the first and the second seals reduce the fuel to oil transfer rate and the oil to fuel transfer rate. The plunger and barrel are configured to be removed from and re-assembled with the annular seal assembly to enable service of these parts and the fuel pump.

Systems and methods are provided for a cantilever beam arrangement that preloads ring segments in a multi0segment piston ring arrangement. A piston assembly comprises a piston that comprises a land. A ring segment is arranged against the land. The ring segment comprises a radially inner surface, a radially outer surface for sealing against a bore, and a boss located on the radially inner surface. The piston assembly also includes a beam spring having a proximal end attached to the piston and a distal end in contact with the boss. The beam spring forces at least a portion of the ring segment radially outward by applying a force on the boss.

A piston ring includes a plurality of first ring pieces placed inside the ring groove in a stacking manner such that the first ring pieces adhere to each other in the axis direction. The first ring pieces include respective piston ring gap portions each having end surfaces separated from each other in the circumferential direction of the first ring pieces such that the end surfaces face each other via a ring gap having a predetermined dimension. The respective piston ring gap portions of the first ring pieces are displaced from each other in the circumferential direction. A closing member is provided to close the piston ring gap portions of the first ring pieces in the radial direction of the first ring pieces.