Pistons and piston assemblies for an internal combustion engine is provided. The piston assembly includes a piston coupled to a connecting rod with a piston pin. The piston pin includes a non-circular outer cross-sectional shape.

The present invention relates to a piston (10) for an internal combustion engine, which has a piston skirt (14) as well as a piston head (13) having a circumferential ring belt (21) and having a circumferential cooling channel (24) closed off with a closure element (26), wherein a circumferential recess (23) is formed between the piston head (13) and the piston skirt (14). According to the invention, it is provided that the closure element (26) consists of at least two subcomponents (27, 28), that each subcomponent (27, 28) has a radially oriented base plate (29) and at least one circumferential collar (31) oriented axially on the outer edge (29a) of the base plate (29), which collar is accommodated in at least one outer fold (34) that runs underneath the ring belt (21).

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 combustion-chamber structure of an engine comprises a combustion chamber which is partitioned by a cylinder block, a cylinder head, and a piston. The piston includes a piston body having an upper surface facing the combustion chamber, a heat-insulation layer provided at least in a central area, in a radial direction, of the upper surface and having smaller heat conductivity than the piston body, a heat-barrier layer provided to cover the upper surface and having smaller heat conductivity than the piston body and the heat-insulation layer, and a heat-diffusion layer provided between the heat-insulation layer and the heat-barrier layer and having larger heat conductivity than the heat-insulation layer and the heat-barrier layer. The heat-diffusion layer comprises a side end edge and an extension portion which contact with the piston body.

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 for an internal combustion engine may include a piston body including a piston skirt, a piston head, and a pocket. The piston head may include a cooling channel for receiving a cooling medium. The cooling channel may be open on a side facing away from a piston crown. The piston may also include at least one cooling channel cover at least partially closing the cooling channel, and a piston pin boss having a boss bore configured to accommodate a piston pin. The piston may further include a piston pin lubricating channel fluidically connected to the cooling channel and extending in a direction of the piston pin. The pocket may at least partially define the piston pin lubricating channel. The at least one cooling channel cover may have at least one lug that is offset radially inward and may, together with the pocket, define the piston pin lubricating channel.

A piston for an internal combustion engine may include a piston body including a piston skirt, a piston head, and a pocket. The piston head may include a cooling channel for receiving a cooling medium. The cooling channel may be open on a side facing away from a piston crown. The piston may also include at least one cooling channel cover at least partially closing the cooling channel, and a piston pin boss having a boss bore configured to accommodate a piston pin. The piston may further include a piston pin lubricating channel fluidically connected to the cooling channel and extending in a direction of the piston pin. The pocket may at least partially define the piston pin lubricating channel. The at least one cooling channel cover may have at least one lug that is offset radially inward and may, together with the pocket, define the piston pin lubricating channel.

Pistons and piston assemblies for an internal combustion engine is provided. The piston assembly includes a piston coupled to a connecting rod with a piston pin. The piston pin includes a non-circular outer cross-sectional shape.

A method for coating a surface of a closed cooling channel, having a plurality of oil supply bores and a plurality of oil discharge bores, of a piston for an internal combustion engine, having a coating medium containing hexagonal boron nitride may include introducing a defined quantity of a coating medium comprising a suspension of hexagonal boron nitride with a solution on a basis of at least one thermally curable inorganic binder and at least one solvent into the cooling channel, spreading the coating medium over the surface of the cooling channel by moving the piston about at least two spatial axes, using a laminar air flow to dry the coating medium spread over the surface of the cooling channel, and thermally curing the coating medium to complete a coating adhering to the surface of the cooling channel.

A piston for an internal combustion engine is formed from an upper part connected to a lower part. The upper part has a combustion bowl, a top land, and a ring belt extending circumferentially around the piston upper part. The lower part contains pin bosses and a piston skirt. A circumferential cooling channel is formed by joining the upper and lower parts. There is an oil inlet formed in one piece with the piston lower part. The inlet has a lower extremity and an upper extremity that terminates at the floor of the cooling channel. A bore extends through the oil inlet from the lower extremity up though the floor of the cooling channel. The circumference of the bore increases from the upper extremity to the lower extremity, so the oil inlet forms a funnel shape.