A piston with an oil return channel may include a piston head, a piston skirt, and an oil return hole. The piston head may include a ring groove. The piston skirt may be connected to the piston head. The piston skirt may have a surface including a concave face window. A connection between the face window and the ring groove may form a residual ring bank. The oil return hole may be formed by milling on the residual ring bank. The oil return hole may connect the ring groove close to the piston skirt with the face window. A depth of the oil return hole may be greater than a depth of the ring groove.

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 steel piston with a bushing applied to pin bore surfaces by laser cladding or laser additive manufacturing is provided. The bushing is formed of metal, such as bronze, and metallurgically bonded to the steel of the piston. Thus, the bushing cannot fail by rotating relative to pin bore surfaces. The bushing has a porosity ranging from 0.05% to 5%, based on the total volume of the bushing, and a thickness ranging from 0.07 mm to 6 mm. Since the metal is applied directly to the steel by laser cladding or laser additive manufacturing, the overall size of the piston is reduced, compared to typical pistons with a separate steel backed bushing, and the possibility of bushing rotation is avoided. The bushing also provides scuffing resistance and increased unit load capacity of the pin bore.

A method for producing a piston for an internal combustion engine may include arranging a piston upper part and a piston lower part in a friction welding device. The piston upper part may include a piston head with a combustion recess. The piston lower part may include two mutually opposite skirt elements connected to one another via two mutually opposite pin bosses. The method may also include arranging a deflecting device configured to deflect at least one weld bead one of on and in the friction welding device. The method may further include joining the piston upper part and the piston lower part to one another via friction welding.

A method for producing a piston for an internal combustion engine may include arranging a piston upper part and a piston lower part in a friction welding device. The piston upper part may include a piston head with a combustion recess. The piston lower part may include two mutually opposite skirt elements connected to one another via two mutually opposite pin bosses. The method may also include arranging a deflecting device configured to deflect at least one weld bead one of on and in the friction welding device. The method may further include joining the piston upper part and the piston lower part to one another via friction welding.

An engine piston having a piston upper part, a piston lower part connected to the piston upper part, a piston pin mounted in the piston lower part connects the piston to a connecting rod, and a first cooling space between the piston upper and lower parts for cooling oil. The first cooling space is connected to a second cooling space formed between the piston upper part and a piston lower part via at least one transfer bore, a cooling oil conduction sleeve for conducting cooling oil through a bore in the connecting rod towards the first cooling space. A guiding surface of the cooling oil conduction sleeve adjoins a support face of the piston lower part. At least one groove circulating in the circumferential direction is introduced into the guiding surface of the cooling oil conduction sleeve and/or into the support face of the piston lower part.

An engine piston having a piston upper part, a piston lower part connected to the piston upper part, a piston pin mounted in the piston lower part connects the piston to a connecting rod, and a first cooling space between the piston upper and lower parts for cooling oil. The first cooling space is connected to a second cooling space formed between the piston upper part and a piston lower part via at least one transfer bore, a cooling oil conduction sleeve for conducting cooling oil through a bore in the connecting rod towards the first cooling space. A guiding surface of the cooling oil conduction sleeve adjoins a support face of the piston lower part. At least one groove circulating in the circumferential direction is introduced into the guiding surface of the cooling oil conduction sleeve and/or into the support face of the piston lower part.

A piston for an internal combustion engine may include a cooling duct having at least one feed opening. The piston may also include a feed funnel arranged within the at least one feed opening. The feed funnel may be fixed in the at least one feed opening via a blind rivet connection.

A piston for an internal combustion engine may include a cooling duct having at least one feed opening. The piston may also include a feed funnel arranged within the at least one feed opening. The feed funnel may be fixed in the at least one feed opening via a blind rivet connection.

A remanufactured piston for an internal combustion engine includes a crown and a skirt. A piston body includes a first piston body end within the crown and an opposite second piston body end. The crown further includes an annular crown body having an annular crown body edge. The first piston body end further includes an annular piston body edge. The annular piston body edge and the annular crown body edge form a joint, and a metallurgical bond attaches the annular crown body to the piston body at the joint.