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.

The present disclosure provides a sealing ring assembly having a sealing ring and a reinforcement, configured to seal a high-pressure region from a lower pressure region of a piston and cylinder device. The sealing ring may be segmented, and a metal layer, wire, or other reinforcement may be affixed to the ring. The reinforcement is placed into tension against the sealing ring, which is correspondingly placed into compression. The composite structure of a relatively brittle sealing ring and reinforcement provides for reduced tensile loads in the sealing ring, thus extending life and reducing the likelihood of failure. The brittle portion of the sealing ring assembly may include a polymer or ceramic such as graphite, which is relatively less strong in tension than compression.

Disclosed is a micropump for delivery of a fluid. The micropump comprises body comprising metering chamber for receiving fluid and groove, and nozzle attached to metering chamber for delivering fluid. A capillary delivers fluid into metering chamber, and piston operates to move axially inside metering chamber. Axial movement of first end of piston (namely, piston face) along path between second end and first end of metering chamber delivers fluid through nozzle. Moreover, groove radially surrounds piston and has common axis with piston. The groove comprises sealing ring operable to move inside groove based on axial movement of piston. The sealing ring is in contact with piston and body. The sealing ring is manufactured using a rubber composition comprising hydrogenated nitrile butadiene rubber (HNBR), and carbon black.

Disclosed is a micropump for delivery of a fluid. The micropump comprises body comprising metering chamber for receiving fluid and groove, and nozzle attached to metering chamber for delivering fluid. A capillary delivers fluid into metering chamber, and piston operates to move axially inside metering chamber. Axial movement of first end of piston (namely, piston face) along path between second end and first end of metering chamber delivers fluid through nozzle. Moreover, groove radially surrounds piston and has common axis with piston. The groove comprises sealing ring operable to move inside groove based on axial movement of piston. The sealing ring is in contact with piston and body. The sealing ring is manufactured using a rubber composition comprising hydrogenated nitrile butadiene rubber (HNBR), and carbon black.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a work stroke from one end to another. The work stroke may include an expansion stroke portion and a non-expansion stroke portion. The non-expansion stroke portion may include a momentum stroke portion, and a compression stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and other locations.

An internal combustion may include a cylinder having a first combustion chamber at one end and a second combustion chamber at an opposing end, first and second cylinder heads located at an end of the first and second combustion chambers, respectively, and a double-faced piston slidably mounted within the cylinder. The piston may be configured to move in the cylinder in a work stroke from one end to another. The work stroke may include an expansion stroke portion and a non-expansion stroke portion. The non-expansion stroke portion may include a momentum stroke portion, and a compression stroke portion. The engine may further include first and second piston rod portions extending from opposite faces of the piston. Passageways in the piston rod portions may be configured to communicate gases between a combustion chamber and other locations.

A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1) ≥ h1(2) and h1(1) ≥ h1 (3), and when h1 (TOTAL) = h1 (1) + h1(2) + h1(3) + h1 (4), h1 (TOTAL) ≥ 3.9 mm.

A combination of piston rings assembled to a piston includes a first compression ring, a second compression ring, a third compression ring and an oil ring. When an axial width of the first compression ring is h1(1), an axial width of the second compression ring is h1(2), an axial width of the third compression ring is h1(3) and an axial width of the oil ring is h1(4), h1(1) ≥ h1(2) and h1(1) ≥ h1 (3), and when h1 (TOTAL) = h1 (1) + h1(2) + h1(3) + h1 (4), h1 (TOTAL) ≥ 3.9 mm.

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.

An oil control ring according the present disclosure includes a pair of side rails, and a spacer expander disposed between the pair of side rails. The spacer expander includes a plurality of sets and each set includes a lug part and a rail facing part. For each set, the lug part is in contact with an inner circumferential surface of either of the pair of the side rails, and the rail facing part is provided adjacent to the lug part and faces a side surface of either of the pair of the side rails. The lug part satisfies a following condition (1):
W/H≥1.5  (1)
In condition (1), W indicates a width of the lug part at a position 0.05 mm away from a highest position of the lug part in a direction towards the rail facing part, and H indicates a height difference between a highest position of a region on the rail facing part adjacent to the lug part and the highest position of the lug part.