Technology is provided for a cylinder with a carbon scraper for use in an opposed piston engine. The cylinder includes a cylinder body having first and second piston bores extending along a central axis for reciprocation of corresponding first and second pistons therein. A chamber bore is located between the first and second piston bores and first and second annular grooves are located on opposite ends of the chamber bore. The chamber bore extends between and is inclusive of a top-dead-center position of a top land of each of the first and second pistons. The first and second piston bores have a piston diameter and the chamber bore has a chamber diameter smaller than the piston diameter. For example, the chamber diameter can be between about 0.004 and about 0.020 inches smaller than the piston diameter.

An internal combustion engine includes: a cylinder in which a piston reciprocates; a cylinder head positioned above the cylinder; a gasket disposed between the cylinder and the cylinder head; a stepped portion formed at an upper end portion of an inner peripheral surface of the cylinder; a ring member having a cylindrical shape provided to the stepped portion; and a seal member that is provided on an upper surface of the ring member and is sandwiched between the ring member and the cylinder head.

This engine structure includes: a cylinder block in which a cylinder bore is formed; a piston provided in the cylinder bore; a cylinder head provided to an upper portion of the cylinder block in a manner to seal the cylinder bore; and a ring that is inserted in the upper end portion of the cylinder bore and has an inner diameter that is smaller than the diameter of the cylinder. A first abradable layer that is worn down by contact with an outer peripheral surface of the piston is formed on an inner peripheral surface of the ring.

A device and method for preventing and removing piston deposit build-up on a piston cylinder assembly of an engine, including a diesel engine, is disclosed. A cylinder having an inner sleeve for receiving a piston, has a piston scraping ring positioned on the cylinder sleeve. The piston scraping ring includes an inner surface, and has a curved or hook shaped feature on its inner surface. The curved or hook shaped feature, named the power groove for the purposes of this application, allows for reduced wear between the piston rings and the cylinder sleeve by reducing the pressure on the piston rings by expanding and reversing the flow of combustion gases. Additionally, this reversal of the combustion gases results in a decrease in blow-by gases passing between the piston rings and cylinder sleeve thereby improving sealing between the piston and the cylinder.

Technology is provided for a cylinder with a carbon scraper for use in an opposed piston engine. The cylinder includes a cylinder body having first and second piston bores extending along a central axis for reciprocation of corresponding first and second pistons therein. A chamber bore is located between the first and second piston bores and first and second annular grooves are located on opposite ends of the chamber bore. The chamber bore extends between and is inclusive of a top-dead-center position of a top land of each of the first and second pistons. The first and second piston bores have a piston diameter and the chamber bore has a chamber diameter smaller than the piston diameter. For example, the chamber diameter can be between about 0.004 and about 0.020 inches smaller than the piston diameter.

A cylinder liner assembly for inclusion in the cylinder bore of an internal combustion engine includes a sleeve-like cylinder liner and an anti-polishing ring to scrape combustion deposits from a piston reciprocally movable along an axis line of the cylinder liner. A fire dam may axially protrude from a first liner end of the cylinder liner and may have an obliquely angled chamfer disposed therein circumscribing the axis line. To locate the anti-polishing ring proximate to the top land of the piston when at the top dead center position, the anti-polishing ring can include a cuff header disposed at the first cuff end that is generally triangular and has an angled undercut corresponding to the obliquely angled chamfer. When mated, the chamfer and angled undercut abut against each other.

A cylinder liner for an opposed-piston engine, and corresponding methods of extending engine durability and thermal management therewith, has opposite ends and a bore with a longitudinal axis for supporting reciprocating movement of a pair of opposed pistons. An intermediate portion of the liner extends between the opposite ends and includes an annular liner portion within which the pistons reach respective TC locations. A liner ring is seated in a portion of the bore in the annular liner portion, between the TC locations, for scraping carbon from top lands of the pistons and/or increasing the thermal resistance of the annular liner portion.

An arrangement may include one of a cylinder liner or a cylinder bore formed in a crankcase of an internal combustion engine, a piston having a peripheral top land and being accommodated in the cylinder liner or cylinder bore, and an annular insert accommodated in the cylinder liner or cylinder bore and extending axially parallel to the piston top land. The cylinder liner or cylinder bore may have a radially inwardly-directed shoulder at an upper free end of the cylinder liner or cylinder bore. The annular insert may have along an upper peripheral free edge of the annular insert, distributed around a circumference of the annular insert, at least two beads or embossments located opposite one another and resting on the radially inwardly-directed shoulder.

A carbon scraper, a method of manufacturing a system with a carbon scraper, and method of scraping carbon from a piston of an internal combustion engine are provided. The carbon escaper includes an outer annular metallic shell portion having an annular recess therein. The annular scraper also includes an inlaid thermal barrier coating portion positioned within the annular recess of the outer annular metallic shell portion such that the inlaid thermal barrier coating portion is concentric with an outer annular metallic shell portion.

This engine structure includes: a cylinder block in which a cylinder bore is formed; a piston provided in the cylinder bore; a cylinder head provided to an upper portion of the cylinder block in a manner to seal the cylinder bore; and a ring that is inserted in the upper end portion of the cylinder bore and has an inner diameter that is smaller than the diameter of the cylinder. A first abradable layer that is worn down by contact with an outer peripheral surface of the piston is formed on an inner peripheral surface of the ring.