A piston for an internal combustion engine may include a piston head and a piston skirt. The piston head may include a piston crown, a circumferential fire land, a circumferential ring belt having a plurality of ring grooves, and a circumferential cooling duct. The cooling duct may be open in a direction away from the fire land and may be at least partially closed by a closure element. The cooling duct may include a cooling duct bottom and a cooling duct ceiling. The piston skirt may have at least two piston bosses connected to one another via at least two running faces. At least one running face may have an inner face connected via a connecting land to an underside of the piston head.

A piston for an internal combustion engine may include a piston head and a piston skirt. The piston head may include a piston crown, a circumferential fire land, a circumferential ring belt having a plurality of ring grooves, and a circumferential cooling duct. The cooling duct may be open in a direction away from the fire land and may be at least partially closed by a closure element. The cooling duct may include a cooling duct bottom and a cooling duct ceiling. The piston skirt may have at least two piston bosses connected to one another via at least two running faces. At least one running face may have an inner face connected via a connecting land to an underside of the piston head.

A piston and methods for constructing a piston for use in an internal combustion engine are presented wherein the piston includes a cylindrical body extending from the crown. The cylindrical body defines a ring groove, and a portion of the cylindrical body defines a non-circular cross-section below the ring groove. The ring groove is configured to correspond with an associated sealing ring. The non-circular cross-section creates a gap between the cylindrical body and an associated cylinder wall enabling a quantity of oil to pass from an annular region between the cylindrical body and the associated cylinder wall.

Piston has crown portion 2 having crown surface 2a defining combustion chamber, thrust-side and anti-thrust-side skirt portions 3a, 3b formed integrally with crown portion and sliding on cylinder wall surface, a pair of apron portions 4a, 4a joined to skirt portions in circumferential direction, recessed portion 6 formed on back surface that is opposite side to crown surface and extending between skirt portions along substantially longitudinal direction, and a plurality of protrusions 7 formed integrally with bottom surface of recessed portion and extending along arrangement direction of skirt portions. At least one end edge in longitudinal direction of protrusion is integrally connected to inner side surface, facing one end edge of protrusion, of recessed portion. Adequate transcription performance to molding surface can therefore be ensured while removing remains of air on bottom side of recessed portion of mold for molding protrusions on crown portion back surface during casting.

The present invention discloses a piston for an engine. The piston comprises a piston body; wherein, a top land, a first compression ring groove, a second land, a second compression ring groove, a third land, an oil ring groove are disposed in turn on the periphery of the piston body from top to bottom; the ratio of the depth of the first compression ring groove to the depth of the second compression ring groove is less than or equal to 1.0; at least one of annular expansion grooves are disposed on the periphery of the second land and/or the third land, to reduce the intra-cylinder carbon deposition and the hydrocarbon emissions in the exhaust gas emissions of the engine and thus improve the engine efficiency and the overall performance of the engine.

In an engine piston assembly of the present invention, a piston structure, together with a piston ring set matched to the piston structure and an inner wall of a cylinder bore body, forms a crevice passage having at least two annular expansion chambers and also having a function of multistage throttling and expansion. The engine piston assembly of the present invention can not only greatly and effectively reduce the intra-cylinder carbon deposition and the hydrocarbon emissions in the exhaust gas emissions of the engine, but also significantly improve the engine efficiency and the overall performance of the engine, so that the present invention is suitable for wide applications.

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 surface area, as viewed looking along the central longitudinal axis, thereby providing an expansive area against which oil being splashed or sprayed can freely contact to cool the piston.

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 surface area, as viewed looking along the central longitudinal axis, thereby providing an expansive area against which oil being splashed or sprayed can freely contact to cool the piston.

The present invention discloses an energy-saving and emission-reducing multistage throttling expansion method for engine. In a crevice passage disposed between the combustion chamber and the crankcase, a multistage throttling is disposed for converting pressure energy of the high-pressure blow-by gas into kinetic energy and momentum, and a multistage expansion is disposed for expanding and dissipating the incoming kinetic energy and momentum of the high-velocity blow-by gas into heat, so that to realize the multistage throttling and expansion method, reduce the leaking of the unburned fuel-air mixture and the burned gas, the hydrocarbon emissions hidden in the intra-cylinder carbon deposition and exhaust gas emissions of the engine, and also improve the engine efficiency and the overall performance of the engine.

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.