A method for producing a piston blank or a piston for an internal combustion engine, includes providing a thickened portion formed in at least one box wall in the direction of thickness approximately in the center thereof, which is at least partly flush with a cooling channel. A resulting piston blank or piston having these features can be made in a casting mold or forging die designed in a corresponding manner.

A piston for an internal combustion engine may include a piston crown having a closed circumferential cooling channel, a piston skirt, a first metallic coolant arranged in the cooling channel and having a metal or metal alloy with a melting point below 250° C., and a second nonmetallic coolant arranged in the cooling channel and having a melting point below 40° C. and a density which is lower than a density of the first coolant.

A piston for an internal combustion engine may include a piston crown having a closed circumferential cooling channel, a piston skirt, a first metallic coolant arranged in the cooling channel and having a metal or metal alloy with a melting point below 250° C., and a second nonmetallic coolant arranged in the cooling channel and having a melting point below 40° C. and a density which is lower than a density of the first coolant.

A piston capable of operating at a high temperature and consequently contributing to a high in-cylinder temperature, as well as reducing engine oil temperature, when used in an internal combustion engine, is provided. The piston includes an upper portion and a lower portion welded together to present a cooling gallery therebetween. The cooling gallery extends circumferentially around a center axis of the piston and is spaced the center axis. A partition is located in the cooing gallery and extends from one inner surface to another inner surface of the cooling gallery. The partition extends circumferentially around the center axis, and divides the cooling gallery into at least a first gallery portion and a second gallery portion. The partition can be formed as one piece with the upper portion or the lower portion. Alternatively, the partition can be formed as a separate piece from the upper portion and the lower portion.

A piston capable of operating at a high temperature and consequently contributing to a high in-cylinder temperature, as well as reducing engine oil temperature, when used in an internal combustion engine, is provided. The piston includes an upper portion and a lower portion welded together to present a cooling gallery therebetween. The cooling gallery extends circumferentially around a center axis of the piston and is spaced the center axis. A partition is located in the cooing gallery and extends from one inner surface to another inner surface of the cooling gallery. The partition extends circumferentially around the center axis, and divides the cooling gallery into at least a first gallery portion and a second gallery portion. The partition can be formed as one piece with the upper portion or the lower portion. Alternatively, the partition can be formed as a separate piece from the upper portion and the lower portion.

A cooling apparatus of a piston according to an exemplary embodiment of the present disclosure may include a piston configured to be formed with a cooling gallery, an inlet fluidly communicated with the cooling gallery, and an outlet fluidly communicated with the cooling gallery, therein, a first oil jet configured to inject cooling oil into the inlet, and a second oil jet configured to inject cooling oil into the outlet.

A cooling apparatus of a piston according to an exemplary embodiment of the present disclosure may include a piston configured to be formed with a cooling gallery, an inlet fluidly communicated with the cooling gallery, and an outlet fluidly communicated with the cooling gallery, therein, a first oil jet configured to inject cooling oil into the inlet, and a second oil jet configured to inject cooling oil into the outlet.

A heavy duty piston for an internal combustion engine comprises a thermally conductive composition filling 10 to 90 vol. % of a sealed cooling gallery. The thermally conductive composition includes bismuth and/or tin. For example, the thermally conductive composition can be a single-phase binary mixture of bismuth and tin. The thermally conductive composition has improved thermal properties, for example a melting point around 139° C., a thermal conductivity around 22 W/m.Math.K, and a thermal diffusivity around 1.43E-5 m.sup.2/s. The thermally conductive composition is not reactive and does not include toxic or cost-prohibitive metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the thermally conductive composition flows throughout the cooling gallery to dissipate heat away from the upper crown and thus improve efficiency of the engine.

A heavy duty piston for an internal combustion engine comprises a thermally conductive composition filling 10 to 90 vol. % of a sealed cooling gallery. The thermally conductive composition includes bismuth and/or tin. For example, the thermally conductive composition can be a single-phase binary mixture of bismuth and tin. The thermally conductive composition has improved thermal properties, for example a melting point around 139° C., a thermal conductivity around 22 W/m.Math.K, and a thermal diffusivity around 1.43E-5 m.sup.2/s. The thermally conductive composition is not reactive and does not include toxic or cost-prohibitive metals. During high temperature operation, as the piston reciprocates in the cylinder bore, the thermally conductive composition flows throughout the cooling gallery to dissipate heat away from the upper crown and thus improve efficiency of the engine.

A one-piece cast piston (10) for an internal combustion engine includes a cooling channel (12) and at least one rib (18) on the inner side of the piston opposite the recess base of a combustion bowl (14).