Abstract: A warm-air heating system for motor vehicles driven by an internal combustion engine, which is equipped with a heat-exchanger adapted to be acted upon by atmospheric air for the transfer of heat from a heat carrier that circulates in a line circulatory system, and with a heat-exchanger also interconnected in the line circulatory system which absorbs exhaust gas heat of the internal combustion engine and gives off the heat to the heat carrier; the line circulatory system for the heat carrier of the heating system is thereby in heat-transferring connection at least with the lubricating oil circulatory system of the internal combustion engine.

Abstract: A sintered hard metal sealing strip particularly for constituting a radial seal in a rotary internal combustion engine, includes a hollow body with longitudinal ends each closed off by a sintered hard metal end face forming part of the hollow body.

Abstract: A rotary piston internal combustion engine of trochoidal construction which includes a housing casing with hollow spaces for a cooling media disposed between housing inner and housing outer walls, whose outer wall is provided with a cooling medium channel; a polygonal piston rotates within the housing casing and slides along its inner wall, and at least one cooling medium bore constructed as nozzle is provided which branches off from the cooling medium channel, is arranged in the housing outer wall and is directed toward the hottest area of the housing inner wall.

Abstract: A radial seal for a rotary piston internal combustion engine, especially of trochoidal construction, which is constituted by a sealing bar, possibly of multi-partite construction, that is guided in an axially parallel groove of a piston and is forced radially outwardly by springs; the springs are thereby arranged separate from one another in series one behind the other--as viewed in the longitudinal direction of the groove.