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 port opening edge shape for a port in a cylinder of an opposed-piston combustion engine is optimized for flow area, as well as for minimization of piston ring clipping. The port opening edge shape includes a top edge, a bottom edge, a first and second side edge connecting the top and bottom edge, and an apex in the top edge. The apex has the minimum radius of curvature of the port opening edge shape. A spline that defines the port opening edge shape can be calculated based upon a maximum height, a full width, an amount or degree of skew, and a minimum radius of curvature. A model can measure values for engine performance and determine which spline defines a port opening edge shape yields a desired engine performance.

A port opening edge shape for a port in a cylinder of an opposed-piston combustion engine is optimized for flow area, as well as for minimization of piston ring clipping. The port opening edge shape includes a top edge, a bottom edge, a first and second side edge connecting the top and bottom edge, and an apex in the top edge. The apex has the minimum radius of curvature of the port opening edge shape. A spline that defines the port opening edge shape can be calculated based upon a maximum height, a full width, an amount or degree of skew, and a minimum radius of curvature. A model can measure values for engine performance and determine which spline defines a port opening edge shape yields a desired engine performance.

According to one embodiment, a drive device includes a first piston reciprocatively along a first direction within a first mount plane, a first crankshaft orthogonal to the first mount plane, a first XY separation crank mechanism between the first piston and the first crankshaft, which converts reciprocating motion of the first piston and rotary motion of the first crankshaft into each other, a second piston reciprocatively along a second direction symmetrical to the first direction within a second mount plane symmetrical to the first mount plane about a central reference plane, a second crankshaft orthogonal to the second mount plane, a second XY separation crank mechanism between the second piston and the second crankshaft, which converts reciprocating motion of the second piston and rotary motion of the second crankshaft into each other, and a coupler-synchronizing mechanism which rotates the first and second crankshafts in synchronous with each other.

A piston arrangement (12) for an internal combustion engine (10) comprises one or more pistons (14) which are at least partly constructed from a technical ceramic material. An axially disposed bore (20) for receiving a heat transfer member (22) is provided in at least one of the pistons (14). The heat transfer member (22) is reconfigurable from a first, solid, state to a second state in which at least part of the heat transfer member (22) is in a liquid state so as to transfer heat away from and thus cool the piston rod (16) as the piston reciprocates. A cylinder arrangement (46) for the internal combustion engine (10) comprises one or more cylinders (48) which are at least partly constructed from a technical ceramic material. One or more grooves (54) are formed in the cylinder (48), to decrease the thermal gradient between the inside and outside of the cylinder (48). A piston (14) for the internal combustion engine (10) comprises a piston rod (16) and a piston crown (18) which is at least partly constructed from a technical ceramic material. An insulation arrangement (40) between the piston rod (16) and the piston crown (18) comprises segments (42) configured such that when disposed on the piston rod (16) axial slots or spaces are defined between the segments (42).