At least one thermal barrier coating member mounted on an inner wall surface, facing a combustion chamber of an engine, of a cylinder liner accommodating a piston slidably along an axial direction, is provided with: a base layer configured to be detachably fitted into a recess formed in the inner wall surface of the cylinder liner; and a thermal barrier coating layer formed on an opposite side of the base layer from the inner wall surface of the cylinder liner. The thermal barrier coating layer is disposed above a piston ring which is positioned at an uppermost position in the axial direction of the cylinder liner when the piston reaches top dead center.

A piston includes a swirl pocket that extends radially from the radially outer lip portion to a lower axial extremity spaced away from the radially outer lip portion a first axial distance. A convex arcuate surface extends downwardly and inwardly from the radially outer lip portion, a concave arcuate surface extends to the lower axial extremity from the convex arcuate surface, and a conical portion extends upwardly and inwardly from the concave arcuate surface to an apex that is spaced a second axial distance from the radially outer lip portion that is less than the first axial distance.

An anti-polish ring for an internal combustion engine is provided. The anti-polish ring includes an axially extending ring portion that is configured to scrape a top portion of a piston in a cylinder liner. The anti-polish ring is configured to accommodate passage of an intake or exhaust valve thereby. The anti-polish ring may include an alignment feature so that the anti-polish ring is inserted in a predetermined orientation in the cylinder. The anti-polish ring may include a heat shield and/or a seating member.

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.

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 engine is disclosed. The cylinder liner may include a cylindrical sleeve with an inner surface and an outer surface extending axially from a first end to a second end. The cylinder liner may also include a void disposed in the first end and concentric to the inner surface of the cylindrical sleeve.

An anti-polishing ring includes a ring body defining an axis of revolution, and a radial direction that is perpendicular to the axis of revolution, and a circumferential direction about the axis of revolution. The ring body includes an outer circumferential surface, a bottom surface, a top surface, and an inner circumferential surface. The inner circumferential surface defines an inner diameter, the ring body defines a radial thickness measured from the inner circumferential surface to the outer circumferential surface, and a ratio of the radial thickness to the inner diameter ranges from 0.015 to 0.020.

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.

Provided is an engine, including: a cylinder including a cylinder liner; a piston provided inside the cylinder liner; a piston ring provided on the piston; a contact detector configured to detect a contact between a step formed in an inner peripheral surface of the cylinder liner and the piston ring; and a compression ratio controller configured to control a top dead center position of the piston so that the piston ring at the top dead center position is located on a combustion chamber side with respect to the step when the contact is detected.

A piston of a cylinder of an internal combustion engine includes: an upper piston crown; a radially outer surface; a plurality grooves arranged on the radially outer surface; and a plurality of piston rings each positioned in a respective one of the grooves. The radially outer surface forms a top land arranged between the upper piston crown and an uppermost one of the grooves of the piston, and the top land has an axial length and a non-abrasion-proof coating.