A piston including a piston crown, the piston crown defining a combustion bowl with a bowl base and bottom surface. A failure initiation structure is provided on the bottom surface of the combustion bowl to initiate favorable fracture at predetermined loads. Such favorable fracture may lead to the a separation of a fragment of the bowl base from the combustion bowl when a predetermined load or pressure is exceeded within the combustion bowl.

A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

Disclosed are novel bridged bi-aromatic phenol ligands and transition metal catalyst compounds derived therefrom. Also disclosed are methods of making the ligands and transition metal compounds, and polymerization processes utilizing the transition metal compounds for the production of olefin polymers.

The invention relates to a piston for an internal combustion engine having an upper part integrally joined to a lower part having a shaft and at least one pin bore. The upper part including a combustion chamber bowl recess and a piston crown with a crown edge. At least one joint is arranged in the region of a ring zone and in an outer wall of the combustion bowl recess, and the ratio of piston compression height (h.sub.1) and the diameter of the piston (d.sub.1) is less than 0.53.

A method for producing a cooling duct piston for an internal combustion engine having a cooling duct in its piston crown. A piston main body is produced with a collar which is circumferential and projects radially in the region of the piston crown. The collar is formed until its outer circumferential edge comes very closely or completely into contact with a bearing region of the piston lower part forming the cooling duct. At least one ring groove is introduced. A ring-free groove is further formed below the ring groove, wherein a dividing plane lies between the outer circumferential edge of the formed collar and an upper side of the piston lower part in the ring-free groove.

A piston of an internal combustion engine having a piston head which has a ring zone and is adjoined by a piston skirt which encloses an inner shape, with two box walls which lie opposite one another and are set back with respect to the outer contour of the piston and with two skirt walls which are not set back with respect to the outer contour of the piston, wherein the box walls receive hubs, wherein the piston skirt has skirt supports which are connected to the hub, wherein the width of the box wall is a point of intersection between the pin axis and the constant-curvature and constant-tangent further course of the box wall, and to a method for producing a piston for internal combustion engines.

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 method for producing a piston for an internal combustion engine may include the steps of: producing a piston main body from a first blank via a deformation process; producing a piston ring part from a second blank via at least one of a deformation process and a casting process; pre-machining the first blank and the second blank, and finish machining a welding surface of the first blank and a welding surface of the second blank; connecting the pre-machined first blank and the pre-machined second blank via a welding process to form a piston body; and performing at least one of a secondary machining and a finish machining of the piston body to produce the piston.

A method for producing a piston may include forming a piston blank in a first forming tool such that the piston blank surrounds a ring carrier configured to receive a piston ring via positive engagement after producing the ring carrier by a sintering process. The piston blank, at least in a circumferential region disposed at a piston head, may be composed of a light metal alloy suitable for forging. The method may also include removing the piston blank from the first forming tool and placing the piston blank in a second forming tool, and inserting a holding-down tool into the second forming tool to hold the ring carrier down. The method may further include pressing a final forming punch into the second forming tool to deform the piston blank and form a piston.

A method for the production of a piston made of steel, for an internal combustion engine, in which the upper piston part is produced using the forging method, and the lower piston part is produced using the forging or casting method, and they are subsequently welded to one another. To simplify the production method and make it cheaper, the upper piston part is forged using the method of hot forming and of cold calibration, to finish it to such an extent that further processing of the combustion bowl and of the upper cooling channel regions can be eliminated.