A thermal insulation film is formed on a bottom surface of a cylinder head facing a top surface of a piston. The thermal insulation film in a region (a circumferential region) of a bottom surface of the cylinder head configuring a squish area in a circumferential edge of a cavity region is formed to be thinner than the thermal insulation film in a region (a cavity region) of the bottom surface of the cylinder head facing a cavity. The thermal insulation film in the circumferential region is polished, and surface roughness thereof is equal to or lower than 3 μm. The thermal insulation film in the cavity region is not polished, and surface roughness thereof is 3 to 8 μm on average.

A barrier ring for a cylinder assembly for an opposed-piston engine fits into a groove fashioned into a portion of the cylinder liner that is adjacent to the top dead center location of the end surfaces of the pistons, in a volume of the cylinder liner that defines the combustion chamber. The barrier ring and groove are part of a barrier assembly that prevents heat generated during combustion from reaching the outer wall of the cylinder assembly, reducing the need for conventional cooling systems and increasing the amount of heat retained in the combustion chamber. The barrier assembly allows for increased engine efficiency because of the combustion heat retained in the combustion chamber, as well as a reduction in the overall size of the engine because of the reduction in engine cooling needed.

A cylinder head for an internal combustion engine, wherein the cylinder head (1) comprises at least one first component part (12) and at least one second component part (13) joined to the at least one first component part (12), wherein the at least one first component part (12) is manufactured with the use of at least one of the group consisting of primary shaping, forming and cutting, wherein the at least one second component part (13) is manufactured with the use of an additive manufacturing method.

A thermal insulator for a cylinder bore wall section having a shape conforming to a shape of the groove-like coolant passage in a setting position of the thermal insulator, in which each of the bore wall insulating sections includes a rubber member, a rear surface pressing member, and elastic members, a coolant passage opening through which coolant flowing on a rear surface side of the supporting section passes to flow to an inner side of the supporting section is formed on at least one place of upper portions of supporting section inter-bore portions, the supporting section has a guide wall formed in a vicinity of the coolant passage opening, and has an inclined wall formed on the rear surface side of the supporting section bore portion, and only a center or a vicinity of the center in an arc direction of each of the bore wall insulating sections is fixed to the supporting section.

A motor vehicle cylinder head is provided with a single flat planar surface in which are formed spaced apart integral inlet and outlet ports used for connecting respective coolant supply and returns to a coolant jacket defined within the cylinder head. The use of a common planar surface for the location of the inlet and outlet ports provides a more reliable sealing of the cylinder head to the respective coolant supply and returns.

The present embodiment relates to an internal combustion engine having an anodic oxide coating formed on at least a portion of an aluminum-based wall surface facing a combustion chamber. The anodic oxide coating has a plurality of nanopores extending substantially in the thickness direction of the anodic oxide coating, a first micropore extending from the surface toward the inside of the anodic oxide coating, and a second micropore present in the inside of the anodic oxide coating; the surface opening diameter of the nanopores is 0 nm or larger and smaller than 30 nm; the inside diameter of the nanopores is larger than the surface opening diameter; the film thickness of the anodic oxide coating is 15 m or larger and 130 m or smaller; and the porosity of the anodic oxide coating is 23% or more.

A 2-cycle, direct-injection diesel engine configured to accommodate low cetane diesel and jet fuels. The engine includes combustion chambers having surfaces which are operable at high temperatures during engine operation to increase the combustion rate of low cetane fuels. The engine is further configured to reduce starting times in cold and/or low pressure situations such as those experienced during attempts to restart a plane engine at relatively high altitudes.

A 2-cycle, direct-injection diesel engine configured to accommodate low cetane diesel and jet fuels. The engine includes combustion chambers having surfaces which are operable at high temperatures during engine operation to increase the combustion rate of low cetane fuels. The engine is further configured to reduce starting times in cold and/or low pressure situations such as those experienced during attempts to restart a plane engine at relatively high altitudes.

A manufacturing method for a cylinder head is described. A masking member is attached to a cylinder head material, which followed by a film formation step. The masking member comprises a mask portion to mask the matching surface with the cylinder block, mask portions to mask each of the openings of intake and exhaust ports and a mask portion to mask at least one narrow region sandwiched between openings of two adjacent port holes and has the shortest distance between opening edges of the two adjacent port holes. All Mask portions are coplanar and linked directly to each other.

A manufacturing method for an engine includes: preparing, as a preparing step, a cylinder head having a surface on which a ceiling surface of a combustion chamber is formed; forming, as a film formation step, a thermal insulation film on the ceiling surface; measuring, as a measurement step, a volume of the thermal insulation film; and selecting, as a selection step, a rank for an engine valve to be used in combination with the ceiling surface so as to correspond to an amount of difference of a measured volume of the thermal insulation film from a designed value of a volume of the thermal insulation film, the rank being selected from a plurality of ranks set in correspondence with thicknesses of umbrella portions of engine valves.