An opposed-piston engine includes pistons, each piston having an annular cavity in the piston's sidewall and positioned between its crown and ring grooves to block transfer of heat from the crown to the piston body.

Provided is a piston for an internal combustion engine, the piston including a body having a piston pin boss for inserting a piston pin thereinto, and a skirt corresponding to a cylinder wall, and a cooling channel provided in the body to allow a refrigerant for cooling the body, to flow therethrough, and having a ring shape including a first channel provided from a refrigerant inlet to a refrigerant outlet along a first outer circumferential direction of the body, and a second channel provided from the refrigerant inlet to the refrigerant outlet along a second outer circumferential direction of the body.

A sub-assembly may include a piston and an injection nozzle for cooling oil for an internal combustion engine. The piston may have a piston skirt and a piston head, where the piston may have a piston crown with an underside, a circumferential ring part, and in the region of the ring part, a circumferential cooling channel with at least one feed opening for the cooling oil. The piston may also have a jet divider for the cooling oil on the underside of the piston crown adjacent to the at least one feed opening. The injection nozzle may be arranged below the jet divider and may be oriented toward the jet divider.

A diesel engine includes a cylinder block having a cylinder cavity defined therein. A cylinder head is coupled to the cylinder block and includes a lower semi-hemispherical surface defined thereon that defines an upper boundary of a combustion chamber. The engine includes a piston slideably disposed within the cylinder cavity that includes a piston crown having an upper surface configured to define a first portion of a lower boundary of the combustion chamber. The upper surface of the piston crown includes an axi-symmetric semi-hemispherical shape configured to correspond to the lower semi-hemispherical surface of the cylinder head.

A galleryless piston for an internal combustion engine and method of construction thereof are provided. The piston has a monolithic piston body extending along a central longitudinal axis. The piston body has an upper wall forming an upper combustion surface with first and second portions, with the first portion extending annularly along an outer periphery of the upper wall and the second portion forming a combustion bowl. The upper wall has an undercrown surface on an underside of the combustion bowl directly opposite the second portion of the upper combustion surface. The undercrown surface has an openly exposed 2-dimensional surface area, as viewed looking along the central longitudinal axis, between about 35-60 percent of an area defined by a maximum outer diameter of the piston body, thereby providing an expansive area against which oil being splashed or sprayed can freely contact to cool the piston.

A columnar hydraulic tappet comprises a housing, in which a plunger is correspondingly mounted. A high-pressure chamber extends between a lower end surface of the plunger and a lower side of the housing. An outer ring groove is disposed on the outer diameter of the housing, an inner ring groove is disposed in the radial inner side of the housing, and housing oil feed holes are disposed between the inner ring groove and the outer ring groove. The lower end inside the housing is provided with a grinding wheel groove, an upper end wall of the inner ring groove of the housing is a first internal cylindrical wall, and a housing inner-wall between the lower end of the inner ring groove of the housing and the grinding wheel groove is a second internal cylindrical wall.

A piston for an internal combustion engine may include a piston head and a piston skirt. The piston head may include a piston crown, an encircling fire land, an encircling ring belt having a plurality of ring grooves and an encircling cooling duct disposed radially inwards from the ring belt. The cooling duct may be open in an axial direction away from the fire land and may be at least partially closed via a closure element. The cooling duct may have a cooling duct base and a cooling duct ceiling. The closure element may be arranged on the piston head to define the cooling duct base in a position above a lowermost ring groove of the plurality of ring grooves.

A device for internal cooling and pressurization of rotary engine, comprising: a mechanical charger, a charger outlet tube, a core cooling intake tube, an engine air intake tube, a first valve, a second valve, and a third valve. The mechanical charger is mounted in a ventilated place. The charger outlet tube is used to dispense air, and the charger outlet tube has two sides, with one side coupled to the mechanical charger. The core cooling intake tube is connected to another side of the charger outlet tube, and is used to dispense air. The engine air intake tube is connected to another side of the charger outlet tube. The device for cooling and pressurization of rotary engine is capable of achieving improved cooling and performance of rotary engine, through switching a plurality of valves, in automatic control manner and/or in remote control manner.

A device for internal cooling and pressurization of rotary engine, comprising: a mechanical charger, a charger outlet tube, a core cooling intake tube, an engine air intake tube, a first valve, a second valve, and a third valve. The mechanical charger is mounted in a ventilated place. The charger outlet tube is used to dispense air, and the charger outlet tube has two sides, with one side coupled to the mechanical charger. The core cooling intake tube is connected to another side of the charger outlet tube, and is used to dispense air. The engine air intake tube is connected to another side of the charger outlet tube. The device for cooling and pressurization of rotary engine is capable of achieving improved cooling and performance of rotary engine, through switching a plurality of valves, in automatic control manner and/or in remote control manner.

A steel piston achieving increased thermal brake efficiency in an internal combustion engine is provided. The piston includes a crown presenting a combustion surface, an outer side wall depending from the combustion surface, an outer cooling gallery, and an undercrown cooling gallery. The outer cooling gallery extends circumferentially along the outer side wall beneath the combustion surface. According to one embodiment, the outer cooling gallery is sealed and filled with air, argon, helium, xenon, or carbon dioxide as a cooling media. In this embodiment, the undercrown cooling gallery is filled with air as a cooling media and includes an open inlet hole having a diameter being from 2% to 4% of an outer diameter of the piston. Alternatively, the undercrown cooling gallery is filled with air, argon, helium, xenon, or carbon dioxide as a cooling media, and the inlet hole is sealed.