A piston formed of steel and/or cast iron for a heavy-duty diesel engine which includes an oil belt for controlling an oil film and thus achieving reduced oil consumption and carbon build-up is provided. The piston includes an uppercrown portion presenting a combustion surface, a ring belt depending from the combustion surface, pin bosses depending from the ring belt, and skirt panels depending from the ring belt and located diametrically opposite one another. The ring belt includes two ring grooves preferentially but accommodates a 3 ring groove version for containing piston rings. The oil belt is located axially below a pin bore on the pin bosses. The oil belt also has a convex shape extending continuously around a circumference of the piston.

A piston assembly, piston therefor and methods of construction are provided. The assembly includes a piston head and connecting rod operably coupled thereto via a wrist pin. The piston head has an upper crown with a combustion bowl and an undercrown surface. The lower crown includes axially aligned pin bores receiving the wrist pin. An upper wall of the lower crown has an oil inlet, an oil outlet and a concave, saddle bearing surface that bears against the wrist pin. A toroid-shaped outer cooling gallery is formed between wall portions of the upper and lower crowns, wherein the outer cooling gallery surrounds an inner cooling gallery. The connecting rod is fixed to the wrist pin for conjoint oscillation. The connecting rod has an oil passage in fluid communication with a through hole in the wrist pin to allow oil to flow therethrough into the inner cooling gallery via the oil inlet.

A one-piece piston having an investment or other permanent or non-permanent mold/die precision cast piston crown, rod flange and piston skirt. The piston crown has a relative constant thickness, a flange requiring minimal machining and a skirt providing for a wall with a support against the angular shifting of the piston. This improves the distribution of heat within such crown and the angular stability of the piston wall at the piston rod connection.

A piston capable of withstanding high temperatures and extreme conditions of a combustion chamber of an internal combustion engine and manufactured with reduced costs is provided. The method of manufacturing the piston includes casting or forging the bulk of the piston as a single-piece with an open cooling gallery from an economical first material, such as steel, cast iron, or aluminum. The method further includes forming a portion of a combustion bowl surface, which is a small area of the piston directly exposed to the combustion chamber, from a second material by additive machining. The second material has a higher thermal conductivity and higher resistance to oxidation, erosion, and oil coking, compared to the first material. The additive machining process is efficient and creates little waste, which further reduces production costs.

A galleryless piston and method of construction provide a piston body forged from a single piece of material having an upper combustion surface extending around a longitudinal center axis along which the piston reciprocates for exposure to a combustion chamber of an internal combustion engine. The upper combustion surface has an asymmetric geometry relative to a center plane extending along the central longitudinal axis in generally perpendicular relation to a pin bore axis.

A casting mold for casting a piston for an internal combustion engine may include a mold body having a surface texture in a region corresponding to a subsequent internal surface of a piston skirt. The surface texture may be defined by a plurality of grooves. The plurality of grooves may have the following dimension: a depth of 0.2 mm<t<0.5 mm, a width of 0.02 mm<b<0.05 mm, and at least two groove walls which are inclined outwardly at 0<<10.

An additive manufactured piston having a crown portion and a skirt portion form of an aluminum-cerium-silicon alloy. The piston includes a least one recess pocket in an unstressed region located at an interface between an inner surface of the crown portion and an outer surface of the skirt portion. The skirt portion includes an outer panel surface defining an external rib adjacent a peripheral end surface, at least one stiffening rib extending from a pin boss to a skirt end, and a wall thickness of between 0.2 mm and 1.0 mm in a region between the external rib and the at least one stiffening rib. The skirt portion further includes an internal first rib having a width W1 on a thrust side portion and an internal second rib having a width W2 located on an anti-thrust side portion, in which W1 is greater than W2.

A 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 galleryless piston having a reduced weight and a reduced operating temperature is provided. The piston includes an undercrown surface exposed from an underside of the piston, a ring belt, pin bosses each presenting a pin bore, and skirt panels depending from the ring belt and coupled to the pin bosses by strut. The piston further includes an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels, the struts, and the pin bosses. The piston also includes outer pockets each extending along the undercrown surface and each surrounded by a portion of the ring belt, one of the pin bosses, and the struts coupling the one pin boss to the skirt panels. Cutouts are located in the pin bosses above the pin bores to increase the area of the undercrown surface and thus allow cooling oil to remove more heat from the undercrown surface.

A piston (10) for an internal combustion engine, includes shaft wall sections (18) for supporting in a cylinder or a cylinder liner, and at least one base support (20) that is connected thereto in the circumferential direction, and which has at least one contour that forms a section of a helix.