A piston for an internal combustion engine may include a surface in a region on a crankshaft side. The piston may include a thermally conductive coating disposed on the surface via thermal spraying.

Any one or more members of an engine, that is, a piston, a cylinder head and a valve, has a wall face disposed face-to-face to a combustion chamber, and the wall face is coated by a heat-insulation coating film. The heat-insulation coating film includes a heat-insulative layer formed on a surface of the wall face, and an inorganic-system coated-film layer formed on a surface of the heat-insulative layer. The heat-insulative layer includes a resin, and first hollow particles buried inside the resin and exhibiting an average particle diameter being smaller than a thickness of the heat-insulative layer. The inorganic-system coated-film layer includes an inorganic compound.

An internal combustion engine comprising: a combustion chamber surrounded by at least an inner wall of a cylinder bore, a cylinder head, a valve and a piston, and a coating layer arranged on at least part of the inner wall of the combustion chamber, wherein the thermal conductivity of the coating layer is, at room temperature, lower than the thermal conductivities of the cylinder block, the cylinder head, the valve and the piston, the thermal conductivity of the coating layer is reversibly increased along with a rise in the temperature of the coating layer, and wherein the heat capacity per unit area of the coating layer is more than 0 kJ/(m.sup.2.Math.K) and 4.2 kJ/(m.sup.2.Math.K) or less.

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.

A piston crown for a piston of a pair of pistons in a two-stroke, opposed-piston, compression ignition combustion engine has a barrier layer and a conductive layer. The barrier layer at least partially surrounds a combustion chamber formed by the piston crown and an end surface of an opposing piston. The conductive layer connects the crown to the rest of the piston body. The barrier layer and the conductive layer are joined either through welding or through the fabrication process. Optionally, the piston crown includes an insulating layer between the barrier and conductive layers.

A galleryless steel piston designed to improve thermal efficiency, fuel consumption, and performance of an engine is provided. The piston includes a steel body portion and a thermal barrier layer applied to an upper combustion surface and/or a ring belt to reduce the amount of heat transferred from a combustion chamber to the body portion. The thermal barrier layer has a thermal conductivity which is lower than a thermal conductivity of the steel body portion. The thermal barrier layer typically includes a ceramic material, for example ceria, ceria stabilized zirconia, and/or a mixture of ceria stabilized zirconia and yttria stabilized zirconia in an amount of 90 to 100 wt. %, based on the total weight of the ceramic material. The thermal barrier layer can also have a gradient structure which gradually transitions from 100 wt. % of a metal bond material to 100 wt. % of the ceramic material.

A thermal barrier coating for an internal combustion engine includes an insulating thermal spray coating, where a chosen material of the insulating thermal spray coating has a thermal conductivity lower than 2 W/mK in fully dense form and the chosen material includes a coefficient of thermal expansion within 5 ppm/K of a coefficient of thermal expansion of a material of a component of the internal combustion engine upon which the coating is placed.

A linear compressor is provided that may include a shell provided with a refrigerant inlet; a cylinder provided inside of the shell to form a compression space; a piston that reciprocates inside of the cylinder to compress a refrigerant in the compression space; and a motor assembly that provides a drive force to the piston and provided with a permanent magnet. The piston may include a piston body having a cylindrical outer circumferential surface and a surface-treated area, which may be processed with a material having a predetermined hardness value, and a valve support provided at an end of the piston body and having a suctioning hole be in communication with the compression space. The valve support may form a first non-surface-treated area, which is not surface-treated.

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 piston capable of reducing undesirable “knock,” reducing hydrocarbon emissions, and providing more complete combustion, is provided. The piston includes a multilayer coating having a thickness of 500 microns or less disposed on an upper combustion surface. The coating includes a bond layer including nickel disposed on the upper combustion surface. A thermal barrier layer including a ceramic composition is disposed on the bond layer. A sealant layer formed of metal is disposed on the thermal barrier layer. A catalytic layer including at least one of platinum, ruthenium, rhodium, palladium, osmium, and iridium is disposed on the sealant layer. The catalytic layer can be disposed on select regions or the entire upper combustion surface to promote combustion through a catalyzed reaction.