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 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 of an internal combustion engine includes a crown portion; a pair of thrust-side and counter-thrust-side skirt portions; and a pair of apron portions connecting the thrust-side skirt portion with the counter-thrust-side skirt portion. Each of the pair of apron portions includes an upper end wall connected with the crown portion, and a pin boss portion supporting a piston pin. A reverse-surface-side portion of the crown portion is formed with a hollow portion extending along an outer surface of the upper end wall of the apron portion. The upper end wall of the apron portion includes a bending portion between an outside surface of the pin boss portion and a circumferential end of the skirt portion. The bending portion bends in a step-like manner from the outside surface of the pin boss portion toward the circumferential end of the skirt portion.

A piston of an internal combustion engine is disclosed. The piston includes a piston head with a piston bowl, a ring part and an annular cooling channel arranged between the ring part and the piston bowl. A closure element is provided to close the cooling channel in a direction away from the piston bowl. At least one guiding element is arranged in the cooling channel. The at least one guiding element provides a lug facing in a direction of an inner cooling channel wall and disposed at least partially circumferentially. The lug of the at least one guiding element is structured and arranged to direct cooling oil present in the cooling channel towards an upper region of the inner cooling channel wall relative to the closure element to facilitate cooling the upper region.

A piston of an internal combustion engine is disclosed. The piston includes a piston head with a piston bowl, a ring part and an annular cooling channel arranged between the ring part and the piston bowl. A closure element is provided to close the cooling channel in a direction away from the piston bowl. At least one guiding element is arranged in the cooling channel. The at least one guiding element provides a lug facing in a direction of an inner cooling channel wall and disposed at least partially circumferentially. The lug of the at least one guiding element is structured and arranged to direct cooling oil present in the cooling channel towards an upper region of the inner cooling channel wall relative to the closure element to facilitate cooling the upper region.

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 compression ignition internal combustion engine includes: a cylinder block and a cylinder head; a piston including a cavity that defines a combustion chamber in cooperation with the cylinder block and the cylinder head; and a nozzle for injecting fuel into the combustion chamber.

The present invention relates to a method for producing a piston (1) for an internal combustion engine from a piston upper part (2) and a piston lower part (3).

The method has the following method steps: producing a piston upper part (2) having a piston top (6), at least parts of a ring section (12) and at least part (7) of a cooling channel (8), by forging or casting for example, producing the piston lower part (3) and closing the part (7) of the cooling channel (8) which is arranged in the piston upper part (2) by means of an additive method, finish-machining the piston (1), including the production of at least one annular groove (4) in the ring support (5) for receiving a piston ring.

In this way, it is possible to provide a piston (1) that has a greater strength in its piston upper part (2), which is subjected to high thermal and mechanical loads, than in its piston lower part (3), which is subjected to lower thermal and mechanical loads, and that permits greater freedom of manufacture in respect of the shape of the piston lower part (3).

The present invention relates to a method for producing a piston (1) for an internal combustion engine from a piston upper part (2) and a piston lower part (3).

The method has the following method steps: producing a piston upper part (2) having a piston top (6), at least parts of a ring section (12) and at least part (7) of a cooling channel (8), by forging or casting for example, producing the piston lower part (3) and closing the part (7) of the cooling channel (8) which is arranged in the piston upper part (2) by means of an additive method, finish-machining the piston (1), including the production of at least one annular groove (4) in the ring support (5) for receiving a piston ring.

In this way, it is possible to provide a piston (1) that has a greater strength in its piston upper part (2), which is subjected to high thermal and mechanical loads, than in its piston lower part (3), which is subjected to lower thermal and mechanical loads, and that permits greater freedom of manufacture in respect of the shape of the piston lower part (3).

An anti-polishing ring includes a ring body defining an axis of revolution, and a radial direction that is perpendicular to the axis of revolution, and a circumferential direction about the axis of revolution. The ring body includes an outer circumferential surface, a bottom surface, a top surface, and an inner circumferential surface. The inner circumferential surface defines an inner diameter, the ring body defines a radial thickness measured from the inner circumferential surface to the outer circumferential surface, and a ratio of the radial thickness to the inner diameter ranges from 0.015 to 0.020.