Abstract: A multipart cooled piston for a combustion engine has a piston upper part of steel comprising a combustion bowl and a ring wall with ring belt, and a piston lower part comprising a piston skirt, pin bosses for receiving the piston pin connecting the piston to the connecting rod, and pin boss supports connected to the piston skirt. An inexpensive manufacture and high form stability are achieved in that a cooling channel formed in the piston upper part has holes towards the piston crown spread over its circumference, with the piston material present between such holes forming supporting ribs that each form sections of an all-round ring rib radially to the longitudinal piston axis (K), The piston lower part has an annular and all-round carrier rib with a connection surface connected to the pin boss supports.

Abstract: A multipart cooled piston for a combustion engine has a piston upper part of steel comprising a combustion bowl and a ring wall with ring belt, and a piston lower part comprising a piston skirt, pin bosses for receiving the piston pin connecting the piston to the connecting rod, and pin boss supports connected to the piston skirt. An inexpensive manufacture and high form stability are achieved in that a cooling channel formed in the piston upper part has holes towards the piston crown spread over its circumference, with the piston material present between such holes forming supporting ribs that each form sections of an all-round ring rib radially to the longitudinal piston axis (K), The piston lower part has an annular and all-round carrier rib with a connection surface connected to the pin boss supports.

Abstract: A single-part cooling channel piston for a combustion engine with a piston head of forged steel comprises a combustion bowl in the piston crown, a ring wall with ring belt and an all-round closed cooling channel level with the ring belt. The piston skirt is connected to the pin bosses attached to the piston head. Inexpensive manufacture together with improved cooling and good form stability of the piston is achieved by providing the cooling channel with holes spread over its circumference towards the piston crown and spaced such that the piston material present between such holes forms supporting ribs for the piston crown.

Abstract: In a plunger piston of aluminum for internal combustion engines the margin of the combustion chamber trough arranged in the piston crown is fiber-reinforced. The proportion of fibers in the basic material to be reinforced varies over the circumference of the combustion chamber trough margin. The marginal zone in the vicinity of the bolt axis (B) here possesses a higher fiber proportion than the trough margin zone adjoining the connecting rod oscillation plane (A). In this way a good temperature change stability of the marginal material is achieved in the zone adjoining the connecting rod oscillation plane (A) and a good fatigue strength is achieved in the zone adjoining the bolt axis (B).

Abstract: A cast aluminum piston for internal combustion engines having mechanically compacted inner boss bore faces, the structure of the aluminum material disposed below these inner faces having a grain pattern orientated in the circumferential direction of the boss bore over a radial depth of at least 0.1 mm and preferably 0.2 mm. This grain pattern is achieved by rolling at a temperature of at least 350 degrees C. up to 400 degrees C. with simultaneous expansion of the bore diameter by about 0.2 to 0.5 mm.