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 piston galleryless piston capable achieving improved thermal efficiency, fuel consumption, and engine performance is provided. The piston includes an undercrown surface exposed from an underside of the piston, a ring belt, pin bosses, and a pair of skirt panels coupled to the pin bosses by struts. The piston includes an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels, struts, and pin bosses. The piston also includes a pair of outer pockets extending along the undercrown surface and each being 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. Each pin boss includes an opening extending from the inner undercrown region to one of the outer pockets for conveying cooling oil. The opening is located between a pin bore of the associated pin boss and the undercrown surface.

A method for producing a cooling channel system for an internal combustion engine, which has a cooling channel in the piston crown. The piston crown is adjoined by a lower piston part having a piston boss, pin bores and piston skirts. Firstly, a piston blank having a peripheral collar projecting radially in the region of the piston crown is produced, wherein the collar, forming a subsequent ring zone wall is then reshaped and, in a transition area between the piston crown and the lower piston part, a contact area for the collar is formed, and the collar is reshaped in such a way until the outer radially peripheral edge comes very close to or completely into contact with the contact area in order to form a closed cooling channel. Following the reshaping, the end region of the ring zone wall forms a defined gap (X) with respect to the upper edge of the piston skirt.

A method for producing a piston for an internal combustion engine, which piston has at least one cooling channel and is produced from at least one upper part and one lower part. The cooling channel of the piston is formed of the upper part and the lower part where the upper part and the lower part of the piston are each produced by means of a forging process At least one rib-like element, in particular, at least one rib, is additionally forged during the forging of the upper part in an area of the cooling channel and/or at least one rib-like element, in particular, at least one rib, is additionally forged during the forging of the lower part in an area of the cooling channel. Two alternative production methods and to a piston for an internal combustion engine are disclosed.

A method and apparatus for simultaneously producing a first piston part and a second piston part via a forging device may include an upper die, at least one intermediate die, and a lower die. A first billet may be placed between the upper die and the intermediate die, and a second billet may be placed between the intermediate die and the lower die. The upper die and the lower die may be configured to be moved toward each other, whereby the first piston part is forged from the first billet and the second piston part is forged at the same time from the second billet. The upper die and the lower die may then be configured to be moved apart, and the piston parts may be removed.

A method for producing a piston of an internal combustion engine, with a cooling duct, may include producing a piston blank with a cooling duct, closing an inlet and an outlet of the cooling duct by at least one closure element, machine-finishing the piston blank, and removing the at least one closure element.

A piston for an internal combustion engine having an upper part joined by a positive material connection to a lower part, wherein the lower part includes a skirt and at least one pin bore, wherein the upper part includes a combustion bowl and a piston crown with a crown edge, wherein at least one joining point is located in the area of a ring belt and/or in an outer wall of the combustion bowl. A method for producing a piston for internal combustion engines is disclosed.

A piston for an opposed-piston, internal combustion engine includes a crown with an end surface having a bowl shaped to form a combustion chamber with an end surface of an opposing piston in the opposed-piston engine. A substantially circumferential top land of the crown meets the end surface at a substantially circular peripheral edge, and a skirt comprising a sidewall extends from a substantially circumferential belt region of the crown. A wristpin bore with a wristpin axis opens through the sidewall. The end surface of the piston includes a pair of injection regions across which fuel is injected into the bowl. The injection regions are disposed in substantially diametrically-opposed quadrants of the end surface which are defined by the wristpin axis and a connecting rod envelope axis substantially orthogonal to the wristpin axis. Each injection region extends along a respective arc concentric with the substantially circular peripheral edge.