A porous alumina layer with a sealer (i.e., a coating layer) is formed on a top surface or a piston (i.e., a second cavity surface and a second squish surface) and a surface of a bottom surface of a cylinder which forms a cavity area CA (i.e., a first cavity surface). The porous alumina layer without the sealer (i.e., an exposed layer) is formed on a surface of the bottom surface which forms a squish area SA (i.e., a first squish surface).

The present invention relates to a tribological system (1; 2) comprising a first body (102; 105) and a second body (101; 107), which each form a component of an internal combustion engine (100), in particular a piston (102), a piston ring (105) or a cylinder (101, 107), and the surfaces (112, 108, 113) of which have a first and a second material area (11, 12) which come into contact with each other at least in some regions during operation and form a tribological contact, wherein the first and/or the second material area (11, 12) is formed as a layer on the basis of chromium oxide or aluminum chromium oxide. The invention also relates to an internal combustion engine (100) having such a system (1; 2).

A method of forming an insulated composite piston head may include: creating a preformed aluminum or aluminum alloy foam core; suspending the preformed foam core in a piston head mold; forming a molded piston head and removing it from the mold; depositing an insulating material on at least one surface of the molded piston head; performing at least one machining operation on the molded piston head so it conforms to a predetermined specification for the insulated composite piston head; and optionally applying a lubricious piston coating to at least a portion of the outer surface of the insulated composite piston head.

An insulated composite piston head that includes three or more layers is formed and used in a combustion engine. The first layer is an aluminum or aluminum alloy foam core. The second layer is a metal layer that at least partially encapsulates the foam core; wherein the metal layer is selected to be aluminum or an aluminum alloy. The third layer is a layer of an insulating material located on at least one surface of the metal layer. The deposition of the insulating layer is accomplished via the use of a coaxial laser process.

A piston for an internal combustion engine and method of construction thereof are provided. The piston includes an upper crown formed at least in part by a first metal material and a thermally insulating insert. The upper crown has an upper wall forming an upper combustion surface and a ring belt region. The upper combustion surface is formed at least in part by the thermally insulating insert. The thermally insulating insert has a base surface with pores extending upwardly therein. The first metal material is infused and solidified in the pores, with the first metal material forming a first bonding surface. The piston further includes a body portion formed from a second metal material. The body portion provides pin bosses having coaxially aligned pin bores and diametrically opposite skirt portions. The body portion has a second bonding surface bonded to the first bonding surface of the first metal material.

An internal combustion engine (1) including a fuel reformation cylinder (2) for reforming a fuel and an output cylinder (3) for yielding an engine power by combusting a fuel or a reformed fuel, wherein at least a part of the surfaces constituting a volume-variable reaction chamber (23) of the fuel reformation cylinder (2) has a highly heat-insulative material (10).

A porous alumina layer with a sealer (i.e., a coating layer) is formed on a top surface or a piston (i.e., a second cavity surface and a second squish surface) and a surface of a bottom surface of a cylinder which forms a cavity area CA (i.e., a first cavity surface). The porous alumina layer without the sealer (i.e., an exposed layer) is formed on a surface of the bottom surface which forms a squish area SA (i.e., a first squish surface).

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 piston for a cylinder for an internal combustion engine has a piston bowl surface adapted for facing a combustion chamber of the cylinder, the piston bowl surface being provided with a thermal barrier coating layer, wherein the thermal barrier coating layer is provided on a plurality of circumferentially spaced surface parts of the piston bowl surface. A method for producing a piston for a cylinder for an internal combustion engine includes the steps of providing a piston for a cylinder for an internal combustion engine, the piston having a piston bowl surface adapted for facing a combustion chamber of the cylinder, and providing the piston bowl surface with a thermal barrier coating layer, wherein the step of providing the thermal barrier coating layer is made on a plurality of circumferentially spaced surface parts of the piston bowl surface.

A cylinder liner for an engine block includes a first engine block bonding surface, and a second engine block bonding surface that provides a lower heat transfer coefficient between the cylinder liner and an adjacent engine block material than the first engine block bonding surface. The second engine block bonding surface extends a substantial portion of the axial length of the cylinder liner.