A steel piston (1) for a combustion engine, having an upper part in which a ring section (7) with at least one ring groove (8) is arranged, wherein the upper part is adjoined by a lower part that has two opposing skirt wall sections (2), wherein the two skirt wall sections (2) are connected via two mutually opposite case walls (3), wherein a pin bore (4) surrounded by a piston boss (6) is provided in each case wall (3). In one example, there is at least one aperture (14) or at least one recess in the case wall (3) in the region between the piston boss (6) and the skirt wall section (2).

A one-piece piston blank of near-net shape wherein the piston blank has a flange disposed opposite a skirt, the flange being spin-bendable to form a cooling channel with reduced preliminary removal of material relative to conventional forged piston blanks.

A piston of an internal combustion engine may include a piston shaft and a piston head. The piston head may be provided with a closed cooling channel with a cooling medium arranged therein. The piston shaft may have a spherically round cross-sectional shape, wherein a deviation from the roundness with respect to a piston diameter may be less than 0.5 per thousand.

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.

Piston (1) of an internal combustion engine, which piston is designed in structured construction, comprising two oppositely arranged load-bearing skirt wall portions (2), wherein a connecting wall (3) respectively extends, starting from a pin boss (4), in the direction of the side edge of the load-bearing skirt wall portions (2), characterized in that in an interior of the piston (1) is (are) disposed at least one rib (5, 6, 7), preferably three ribs (5, 6, 7), and the material of the regions around the at least one rib (5, 6, 7) is reduced.

A steel piston with an oil gallery, and process for forming a steel piston oil gallery channel, which corresponds to the complex shape of the combustion bowl in the piston crown. The oil gallery channel is first forged to the basic shape that corresponds to the shape of the walls of the combustion bowl. Machine-turning surfaces in the oil gallery channel can be machine-finished as desired. Surfaces in the oil gallery which cannot be machined with conventional turning operations, such as recesses and protrusions into the channel, are left in the original forged condition.

A piston, particularly a piston for use in a diesel engine, particularly a heavy duty diesel engine, is formed from a billet of metal, such that the finished piston has a mass that is at least 50%, and, more preferably, up to about 62%, of the mass of the billet. Other than finishing steps, the piston is formed with a closed gallery, without loss of mass through machining processes.

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 galleryless steel piston for an internal combustion engine is provided. The piston comprises an exposed undercrown surface, a ring belt with ring grooves, pin bosses, skirt panels, and struts. The piston further includes an inner undercrown region and outer pockets extending along the undercrown surface. The inner undercrown region is surrounded by the skirt panels, the struts, and the pin bosses, and each outer pocket is surrounded by a portion of the ring belt, one of the pin bosses, and two of the struts. The piston includes a plurality of oil slots extending through the back wall of one of the ring grooves, typically the third ring groove, to the inner undercrown region and/or the outer pockets to allow drainage of cooling oil. Each oil slot typically has a diameter ranging from 30% to 100% of an axial width of the ring groove.

A galleryless piston including a ring belt with three ring grooves is provided. Each ring groove is formed by an uppermost wall and a lower wall spaced from one another by a back wall. A pair of pin bosses depend from the upper wall, and pair of skirt panels depend from the ring belt and are coupled to the pin bosses by struts. An inner undercrown region is surrounded by the skirt panels and the struts and the pin bosses. A pair of outer pockets extend along the undercrown surface, and each outer pocket is surrounded by a portion of the ring belt and one of the pin bosses and the struts coupling the one pin boss to the skirt panels. The third ring groove includes an oil drain slot extending through the back wall to the outer pockets of the piston for conveying cooling oil.