The invention discloses a method for producing an internal combustion engine piston having at least one cavity which is filled with an alkali metal cooling medium and is subsequently closed. The at least one cavity longitudinally extends from a central point into the piston body toward the piston circumference. The invention further discloses a piston produced according to the method.

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.

Disclosed is a monoblock or cooling channel piston and a method for producing a monoblock piston for use in an internal combustion engine. A piston blank includes a circumferential collar protruding radially in the region of the piston crown is first produced and the collar is then shaped. A contact region on a top region of the piston skirts and the collar is shaped such that the outer circumferential edge thereof points at a distance to the contact region and forms a defined gap. The gap is then sealed by a closure element in order to form a closed cooling channel.

A piston and method of construction thereof are provided. The piston includes an upper crown having an upper combustion surface and a lower crown depending therefrom. The lower crown includes a pair of laterally spaced, axially aligned pin bores configured for receipt of a wrist pin. A substantially closed, annular outer cooling gallery is formed between the upper and lower crowns, wherein a bottom surface of the cooling gallery is formed by a floor of the lower crown. An oil inlet and an oil outlet extend through the floor. The oil inlet includes an upstanding toroid-shaped protrusion that extends upwardly from the floor into the cooling gallery, wherein the protrusion is formed as a monolithic extrusion from the material of the lower crown floor.

A piston and method of construction thereof are provided. The piston includes an upper crown having an upper combustion surface and a lower crown depending therefrom. The lower crown includes a pair of laterally spaced, axially aligned pin bores configured for receipt of a wrist pin. A substantially closed, annular outer cooling gallery is formed between the upper and lower crowns, wherein a bottom surface of the cooling gallery is formed by a floor of the lower crown. An oil inlet and an oil outlet extend through the floor. The oil inlet includes an upstanding toroid-shaped protrusion that extends upwardly from the floor into the cooling gallery, wherein the protrusion is formed as a monolithic extrusion from the material of the lower crown floor.

There is provided a method for manufacturing a piston for a vehicle engine, including: a piston assembling step of forming a piston assembly by assembling a first piston part, a bonding member and a second piston part, wherein the first piston part has two or more bonding surfaces separate from each other and extending in a circumferential direction, and the second piston part has two or more bonding surfaces separate from each other and extending in the circumferential direction; a piston diffusion brazing step of diffusion brazing the first piston part, the bonding member and the second piston part under an open atmosphere by heating the formed piston assembly; and a piston cooling step of cooling a piston unit formed by diffusion brazing the first piston part, the bonding member and the second piston part. The piston assembly includes a locking part for maintaining a position at which the first and second piston parts are assembled, and the method further includes a locking part removing step of removing the locking part from the cooled piston unit.

There is provided a piston with a surface modified layer for an internal-combustion engine by a method using a particle to be ejected made of iron-based alloy having a diameter of 20 to 200 m, a thermal conductivity of 30 W/m.Math.k or less at 25 C., and a specific gravity of 7.5 g/cm.sup.3 or greater. The method includes: first treatment for ejecting the particle onto a surface of a piston made of aluminum-silicon alloy or aluminum-copper-based alloy in a space in which oxygen exists at arc height value of 0.07 to 0.13 mm (N), second treatment for ejecting the particle onto the surface of the piston in a space in which oxygen exists at arc height of 0.13 to 0.22 mm (N), and heating treatment applying to the piston for 1.5 hours or longer at 170 to 190 C. in a space in which oxygen exists.

There is provided a piston with a surface modified layer for an internal-combustion engine by a method using a particle to be ejected made of iron-based alloy having a diameter of 20 to 200 m, a thermal conductivity of 30 W/m.Math.k or less at 25 C., and a specific gravity of 7.5 g/cm.sup.3 or greater. The method includes: first treatment for ejecting the particle onto a surface of a piston made of aluminum-silicon alloy or aluminum-copper-based alloy in a space in which oxygen exists at arc height value of 0.07 to 0.13 mm (N), second treatment for ejecting the particle onto the surface of the piston in a space in which oxygen exists at arc height of 0.13 to 0.22 mm (N), and heating treatment applying to the piston for 1.5 hours or longer at 170 to 190 C. in a space in which oxygen exists.

Disclosed are hollow pistons made from a single piece of starting material and methods of manufacturing unitary hollow pistons from a single solid rod as a starting material.

Disclosed are hollow pistons made from a single piece of starting material and methods of manufacturing unitary hollow pistons from a single solid rod as a starting material.