Abstract: A spark plug for an internal combustion engine, the spark plug having at least two electrodes, in which the electrodes are formed of a first part made of a substrate material and a surface part more durable than the substrate material. The surface part of the spark plug is joined to the first part via an intermediate part making use of explosion welding. The method also relates to a method for producing a spark plug for an internal combustion engine, the spark plug having at least two electrodes.

Abstract: A spark plug for an internal combustion engine, the spark plug having at least two electrodes, in which the electrodes are formed of a first part made of a substrate material and a surface part more durable than the substrate material. The surface part of the spark plug is joined to the first part via an intermediate part making use of explosion welding.

Abstract: Piston unit for an internal combustion engine, especially for a large diesel engine, comprising at least three main parts located in successive order in the direction of the longitudinal axis of the piston and to be connected to each other. The piston unit includes a uniform upper part (3), which defines, when installed within a cylinder of the engine, a combustion chamber from the side of the piston and which is fixed inside of the piston at its central region to a middle part (2) of the piston unit preferably by means of a screw (4) or the like. At least the main part of, preferably all of the piston ring grooves (7) are arranged on a middle part (2). In addition the upper part (1) is selected to be of a material with better heat resistance than that of the middle part (2) and of a lower part (1).

Abstract: Piston unit for an internal combustion engine, especially for a large diesel engine, comprising at least three main parts located in successive order in the direction of the longitudinal axis of the piston and to be connected to each other. The piston unit includes a uniform upper part (3), which defines, when installed within a cylinder of the engine, a combustion chamber from the side of the piston and which is fixed inside of the piston at its central region to a middle part (2) of the piston unit preferably by means of a screw (4) or the like. At least the main part of, preferably all of the piston ring grooves (7) are arranged on a middle part (2). In addition the upper part (1) is selected to be of a material with better heat resistance than that of the middle part (2) and of a lower part (1).