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 parent bore cylinder block of an internal combustion, opposed-piston engine includes cooling passages that are formed using a 3-D printed casting core. The casting core can include portions that are ceramic. The parent bore cylinder block can include multiple cylinders, each cylinder with cooling passages and turbulence inducing features in those cooling passages, particularly surrounding the central portions of the cylinders.

A uniflow engine includes a cylinder having a cylinder wall, a volume exterior to the cylinder, at least one channel extending between the cylinder wall and the volume, and a valve outside of the cylinder configured to open and close flow communication between the cylinder and the volume through the channel.

A cylinder for an internal combustion opposed-piston engine includes a bore, either as part of the cylinder directly or of a liner. The bore has a surface for guiding a pair of pistons disposed for opposing movement in the cylinder. The cylinder bore has three zones of surface finishes: an inner zone extending between and including exhaust and intake ports, where only piston compression rings travel on the bore surface; two instances of an outer zone where only piston oil control rings travel on the bore surface; and two instances of a port zone where both types of rings travel on overlapping paths in the same bore surface portion. Each zone may have a particular surface finish that is tailored to specific requirements including oil control, ring wear, and scuff resistance relevant to the zone.

An opposed-piston engine includes an engine block, at least two intake valves, and at least two exhaust valves. The engine block includes a first center section and a second center section. The first center section defines a first cylinder half bore having a first longitudinal axis and a first open end. The second center section defines a second cylinder half bore having a second longitudinal axis and a second open end. The second longitudinal axis is offset from the first longitudinal axis. The first and second open ends overlap to form and opening therebetween that places the first and second cylinder half bores in fluid communication with one another to form a single cylinder. The intake valves are arranged at the first open end of the first cylinder half bore. The exhaust valves are arranged at the second open end of the second cylinder half bore.

An engine block for an opposed-piston engine includes a first center section and a second center section. The first center section defines a first cylinder half bore having a first longitudinal axis and a first plurality of fastener bores. The second center section defines a second cylinder half bore having a second longitudinal axis and a second plurality of fastener bores that extend from a first end thereof to a second end thereof. The second center section is configured to abut the first center section such that: the first and second cylinder half bores are in fluid communication with one another to collectively form a single cylinder; the first and second longitudinal axes are offset from one another; and the first and second pluralities of fastener bores are aligned with one another for receiving a first plurality of fasteners to join the first and second center sections to one another.

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.

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.

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.

In ported engine constructions, cooling of piston crowns and cylinder liners results in reduction or elimination of bore/liner distortions, thus ensuring circularity of the bore/piston interface throughout engine operation. Consequently, the need for heavily-tensioned piston rings is eliminated. Such engine constructions incorporate annular low-tension compression seals on the pistons, which substantially reduce port bridge wear during all phases of engine operation while also limiting blow-by during combustion.