Abstract: A rotary piston internal combustion engine includes a housing defining a cylinder chamber in the form of a circular ring. An even number of pistons circulate in the piston chamber and are of a circular cross-section adapted to the cylinder chamber. Two piston carriers mounted rotatably about the axis of the cylinder chamber each carry half the number of pistons, the peripheral surfaces of the piston carriers being such that they supplement the internal surface of the cylinder chamber to constitute a circular cross-section which corresponds to the pistons and against which piston rings on the pistons seal. At least one sealing ring is accommodated between the piston carriers and between each piston carrier and an oppositely disposed wall of the housing in an annular groove of the housing or a piston carrier respectively. The sealing ring bears against a co-operating surface of the respective piston carrier under a force which acts out of the annular groove.

Abstract: A lobed rotor machine including an annular cylinder chamber having inlet and outlet openings, four working pistons movable in pairs in the cylinder chamber, two piston carriers for supporting respective pairs of the working cylinder and rotatable about a common machine axis and displaceable relative to each other, and guide channels formed inside of each of the two piston carriers and defining supply channels and return channels for communicating cooling medium to the pistons.