It is an object of the present invention to provide a novel internal-combustion engine piston which makes it possible to achieve both an improvement in thermal efficiency and a reduction in exhaust harmful components, and to suppress the occurrence of abnormal combustion such as knocking and pre-ignition. A cooling passage is formed in a piston, and on a top face of the piston are provided a first heat shielding layer composed of a material having a lower thermal conductivity and volumetric specific heat than those of a piston base material, and a second heat shielding layer composed of a material having a lower thermal conductivity and volumetric specific heat than those of the first heat shielding layer, wherein a first distance between the first heat shielding layer and the cooling passage is set to be less than a second distance between the second heat shielding layer and the cooling passage. A cooling loss can be reduced by the second heat shielding layer, and the vaporization of fuel adhering to the piston can be promoted by the first heat shielding layer to reduce exhaust gas harmful components. Since the first distance is less than the second distance, the temperature of the first heat shielding layer does not rise excessively, whereby the occurrence of knocking and pre-ignition can be suppressed.

A piston for a compressor and a compressor including the same are disclosed. The piston is used in a compressor which compresses and discharges refrigerant suctioned into a cylinder. The piston includes a cylindrical slider and a head. The slider has an outer diameter corresponding to an inner diameter of the cylinder and defines a suction space in which the refrigerant suctioned in the cylinder is received. The head is coupled to the slider, in which a compression space is provided in the front and a suction space is provided in the rear, and in which a suction port communicating with the suction space and the compression space is formed, in which the head includes an inner body and an outer body surrounding the inner body, and the suction port is formed between the inner body and the outer body.

Fuel is ignited in an opposed-piston engine by the mating of unique protruding and recessed portions of opposed pistons.

Fuel is ignited in an opposed-piston engine by the mating of unique protruding and recessed portions of opposed pistons.

In a piston of an internal combustion engine in which a recessed portion that holds an intake air swirling flow is formed on a crown surface of the piston, the crown surface includes a heat insulating film formation portion having a heat insulating film whose thermal conductivity is lower than a base material of the piston, the heat insulating film whose thermal capacity per volume is smaller than the base material of the piston, and a heat insulating film non-formation portion provided at a position on the more outside of a cylinder bore side of the internal combustion engine than the heat insulating film formation portion, the heat insulating film non-formation portion not having the heat insulating film.

In a piston of an internal combustion engine in which a recessed portion that holds an intake air swirling flow is formed on a crown surface of the piston, the crown surface includes a heat insulating film formation portion having a heat insulating film whose thermal conductivity is lower than a base material of the piston, the heat insulating film whose thermal capacity per volume is smaller than the base material of the piston, and a heat insulating film non-formation portion provided at a position on the more outside of a cylinder bore side of the internal combustion engine than the heat insulating film formation portion, the heat insulating film non-formation portion not having the heat insulating film.

An internal combustion engine includes a hollow cylinder, a piston within the hollow cylinder, and a cylinder head. A base valve assembly at a base of the hollow cylinder permits or restricts fluid flow from an intake manifold into a sub-chamber below the piston. The piston includes at least one intake port connecting a combustion chamber above the piston with the sub-chamber, and a transfer valve that opens and closes the at least one intake port. When the transfer valve opens the at least one intake port, fluid is permitted to flow from the sub-chamber to the combustion chamber. The internal combustion engine operates according to a four-stroke piston cycle, wherein multiple intake stages are provided. The intake stages may include intake of air into the sub-chamber during a compression stroke, transfer of air from the sub-chamber to the combustion chamber during a power stroke, intake of air-fuel mixture into the sub-chamber during an exhaust stroke, and transfer of air-fuel mixture from the sub-chamber to the combustion chamber during an intake stroke.

A piston assembly for an internal combustion engine of a motor includes a piston head having an outer diameter surface spaced a first distance from the longitudinal axis and an annular surface spaced a second distance from the longitudinal axis, with the second distance being less than the first distance. Upper and lower walls extend between the annular surface and the outer diameter surface so as to define an annular groove in the outer diameter surface. A piston ring is received within the annular groove and includes an inner diameter surface facing the annular surface of the piston head. The inner diameter surface of the piston ring and the annular surface of the piston head cooperate with one another to define a plurality of pockets angularly spaced from one another about the longitudinal axis and configured to receive oil.

A clutch assembly for a transmission of an agricultural work vehicle. The clutch assembly includes a housing, a clutch pack located within the housing, a piston chamber located within the housing, and a multipart piston located within and slidable relative to the piston chamber. The multipart piston is operably connected to the clutch pack for engaging and disengaging the clutch pack. The multipart piston includes a lower piston extension part. The clutch assembly further includes a balance chamber that is located within the housing. The lower boundary wall of the balance chamber and the lower boundary wall of the piston chamber are radially separated from one another by a substantial distance. The lower piston extension part is located within the balance chamber for adding to a collective surface area of the balance chamber.

A clutch assembly for a transmission of an agricultural work vehicle. The clutch assembly includes a housing, a clutch pack located within the housing, a piston chamber located within the housing, and a multipart piston located within and slidable relative to the piston chamber. The multipart piston is operably connected to the clutch pack for engaging and disengaging the clutch pack. The multipart piston includes a lower piston extension part. The clutch assembly further includes a balance chamber that is located within the housing. The lower boundary wall of the balance chamber and the lower boundary wall of the piston chamber are radially separated from one another by a substantial distance. The lower piston extension part is located within the balance chamber for adding to a collective surface area of the balance chamber.