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 thermal insulator for a cylinder bore wall includes bore wall insulating sections set for each of the bore walls of the cylinder bores, and a supporting 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.

The present invention can provide a thermal insulator that has high adhesion to a wall surface on a cylinder bore side of a groove-like coolant passage, can insulate selectively a portion which needs to be insulated, and has high cooling efficiency of an upper portion of a boundary of the bore walls of the cylinder bores and the vicinity of the boundary.

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.

An engine cylinder head includes an internal metal structure forming an upper portion of a combustion chamber. The internal metal structure includes a semi-compliant coating configured to absorb thermal expansion of the internal metal structure. The engine cylinder head also includes a polymer composite forming an external structure at least partially surrounding the internal metal structure.

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 cylinder head, an element and a base plate of a longitudinal piston engine having a cylinder head body and a base plate comprising at least one element, the base plate being interposed between a combustion chamber and the cylinder head body, comprising an upper face facing the cylinder head body and an opposing lower face arranged to face the combustion chamber and being attached to the cylinder head body, the cylinder head body being made from a material with a mass density and hardness that are less than those of the material constituting the base plate. The base plate and the body are assembled by screws for fastening the base plate to the cylinder head that are located towards the periphery of the base plate and of the body and by at least one part for fastening the cylinder head to the base plate including a threaded end designed to be engaged in a corresponding orifice of the base plate, said orifice being located closer to the center of the base plate than the fastening screws.

In a heat-insulation film, porous plate fillers are dispersed in a matrix to bond the porous plate fillers. The porous plate filler includes plates having an aspect ratio of 3 or more, a minimum length of 0.1 to 50 m and a porosity of 20 to 90%. In the heat-insulation film, a volume ratio between the porous plate fillers and the matrix is from 50:50 to 95:5. In the heat-insulation film in which the porous plate fillers are used, a length of a heat transfer path increases and a thermal conductivity can be decreased, as compared with a case where spherical or cubic fillers are used.

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 m. The thermal insulation film in the cavity region is not polished, and surface roughness thereof is 3 to 8 m on average.

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.

The invention provides a friction-welded structure assembly, comprising a first workpiece (10B), a second workpiece (10C) and a friction welding connecting part (10A). The lower side of the friction welding connecting part (10A) has a first friction welding junction interface (10H) which is in contact with a surface of the first workpiece (10B) and a second friction welding junction interface (11H) which is in contact with a surface of the second workpiece (10C). The friction welding connecting part (10A) is tightly pressed on both the first workpiece (10B) and the second workpiece (10C) which are positioned to be relatively corresponding and fixed to each other, while being moved under a pressure, so as to heat said first friction welding junction interface (10H) and said second friction welding junction interface (11H), then said friction welding connecting part (10A) is stopped under the pressure, and said first friction welding junction interface (10H) and said second friction welding junction interface (11H) become cool, thereby said first workpiece (10B) and said second workpiece (10C) are welded together to form the friction-welded structure assembly via said friction welding connecting part (10A). Also, The invention relates to a water-cooled internal combustion engine cylinder head using the friction-welded structure assembly described above.