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.

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 internal combustion engine is provided. Facing pistons eliminate a cylinder head, thereby reducing heat losses through a cylinder head. Facing pistons also halve the stroke that would be required for one piston to provide the same compression ratio, and the engine can thus be run at higher revolutions per minute and produce more power. An internal sleeve valve is provided for space and other considerations. A combustion chamber size-varying mechanism allows for adjustment of the minimum size of an internal volume to increase efficiency at partial-power operation. Variable intake valve operation is used to control engine power.

In one configuration, the present disclosure provides a cylinder including a first housing, a second housing, and an insert. The first housing includes a first body portion and a first collar portion. The first body portion has a first inner diameter, and the first collar portion has a second inner diameter that is greater than the first inner diameter. The second housing includes a second body portion and a second collar portion. The second body portion has a third inner diameter and the second collar portion has a fourth inner diameter that is greater than the third inner diameter. The second housing is coupled to the first housing such that the first and second collared portions cooperate to form an annular channel. The insert is disposed within the annular channel formed by the first and second collared portions.

A fuel injector mounting assembly in an opposed-piston engine allows for mounting of a fuel injector in a cylinder block without significantly deforming the wall of the cylinder into which the injector is configured to deliver fuel. The fuel injector mounting assembly includes a clamping arrangement to clamp the fuel injector to the cylinder block, an elongate tubular sleeve that sheathes a nozzle portion of the fuel injector, and a spanner nut attached to the elongate tubular sleeve. Clamping loads applied to retain the fuel injector in the cylinder block are controlled by the spanner nut.

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).

A cylinder for opposed-piston engines includes a liner with a bore and longitudinally displaced intake and exhaust ports near respective ends thereof. An intermediate portion of the liner between the exhaust and intake ports contains a combustion chamber formed when the end surfaces of a pair of pistons disposed in opposition in the bore are in close mutual proximity. A compression sleeve encircles and reinforces the intermediate portion of the liner. An annular grid of pegs disposed between the intermediate portion and the compression sleeve supports the compression sleeve against the liner and defines a turbulent liquid flow path extending across the intermediate portion in a direction that parallels the longitudinal axis of the liner.

A cylinder assembly with a cylinder liner and a sleeve is provided that includes features that reduce coolant flow stagnation. The sleeve encloses a center section of the cylinder liner to form cooling channels that removes excess heat from the combustion area of the cylinder. The cylinder liner includes features for cooling between bridges in the cylinder's exhaust port.

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 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.