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.

A heavy duty piston for an internal combustion engine comprises a thermally conductive composition filling 10 to 90 vol. % of a sealed cooling gallery. The thermally conductive composition includes bismuth and/or tin. For example, the thermally conductive composition can be a single-phase binary mixture of bismuth and tin. The thermally conductive composition has improved thermal properties, for example a melting point around 139° C., a thermal conductivity around 22 W/m.Math.K, and a thermal diffusivity around 1.43E-5 m.sup.2/s. The thermally conductive composition is not reactive and does not include toxic or cost-prohibitive metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the thermally conductive composition flows throughout the cooling gallery to dissipate heat away from the upper crown and thus improve efficiency of the engine.

This piston for internal combustion engines, which is capable of achieving high heat shielding properties and high durability, comprises: a base that is formed from aluminum or an aluminum alloy; a composite material part which is formed in a first region of the surface of the base, and which is formed from a composite material that is reinforced with inorganic fibers or whiskers; and an alumite coating film that is formed on the composite material part and a second region of the surface of the base, said second region being different from the first region.

A ring carrier for a piston for an internal combustion engine is formed by a carrier body having an outer circumferential surface, an inner circumferential surface, a top surface and a bottom surface, with at least one ring groove formed in the outer circumferential surface. An outer circumferential portion of the ring carrier is formed of gray iron, and an inner circumferential portion is formed of ductile iron. A transition region between the outer circumferential portion and the inner circumferential portion intersects upper and lower flanks of the ring groove, so that an outer circumferential extent of the flanks is formed of gray iron and an inner circumferential extent of the flanks is formed of ductile iron.

A piston includes an upper member having a crown and a combustion surface extending radially inward from the crown. The upper member includes concentrically oriented first and second upper connecting surfaces integrally formed on the bottom side of the upper member. At least one of the upper connecting surfaces includes a curvilinear and/or multi-arcuate cross-sectional profile. The piston also includes a lower member having a pair of opposing skirts, each skirt defining a bore. The lower member also includes concentrically oriented first and second lower connecting surfaces integrally formed on a top side of the lower member. The lower member is integrally connected to the upper member by friction welding. The curvilinear and/or multi-arcuate profile enables a shortened distance between the top surface of the crown and the bore centerline of the bore. Methods of manufacturing the piston are also disclosed.

The present invention relates to a process for producing a piston made of hypereutectic AlSi alloy with a cast iron Alfin ring and a piston obtained through said process. The process according to the invention allows to obtain high adhesion of the Alfin ring to the piston body, making it particularly suitable for use in high performance engines.

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.

A cylinder liner for an internal combustion engine may include an aluminum alloy material including a magnesium content of at least 0.3% by weight, a liner body having a circumferential face, and an adapter layer of silicon oxide disposed on the circumferential face. The adapter layer may include at least one of a potassium oxide content and a sodium oxide content of greater than or equal to 0% by weight.

An insert part for a cast piston of an internal combustion engine may include a powder, such as a sintered powder material, containing at least iron or alloys thereof, and having a capacity for being infiltrated. The powder may contain particles having different grain sizes, and up to 4% by volume of the powder may include particles having a diameter smaller than 75 m.

A steel piston for heavy-duty diesel engines designed with features that increase adiabaticity, reduce weight, and improve passive cooling without loss of power density is provided. The piston includes a pair of skirt walls extending longitudinally from a crown to a lower end. The skirt walls include a plurality of heat sink wells extending axially from the crown to a lower end of the skirt wall. Each heat sink well is at least partially filled with a cooling medium and is sealed. The piston also includes a plurality of ribs each radially aligned with one of the heat sink wells and extending inwardly and upwardly from a first rib end at an inner surface of the skirt wall to a second rib end at the inner surface of the crown.