Abstract: A rotary piston mechanism for internal combustion engines, fluid motors, pumps and the like has an outer body enclosing a chamber that is defined by curvilinear walls that circumscribe the chamber axis, and a generally elongated rotor is confined in the chamber and rotatably supported by a rotor carrier that closes one end of the chamber and is rotatably supported on the chamber axis by the outer body so that the rotor rotates on the rotor axis which is parallel to the chamber axis and around the chamber axis over a closed path, the sense of rotation of the rotor on the rotor axis being opposite to the sense of rotation of the rotor axis around the chamber axis, and the rotor is oriented on the rotor axis by a gear train between the rotor and the rotor carrier.

Abstract: A rotary piston mechanism for internal combustion engines, fluid motors, pumps and the like has an outer body enclosing a chamber that is defined by three equal curvilinear walls that circumscribe the chamber axis and define an equilateral triangle in a plane perpendicular to the chamber axis, the walls being convex with respect to the axis, and a generally elongated rotor confined in the chamber of length equal to the span of the chamber along a bisector of any of the angles of the equilateral triangle defined by the chamber walls, the rotor being pivotally supported to rotate about a rotor axis which is parallel to the chamber axis and moves around the chamber axis over a closed path, the sense of rotation of the rotor on the rotor axis being opposite to the sense of rotation of the rotor axis around the chamber axis.