Abstract: Systems for facilitating conversion between reciprocating linear motion and rotational motion include a continuous undulating track circumscribing a circular profile and generally defining a cylindrical volume having a central axis; a reciprocator that is configured to linearly reciprocate along the central axis; a converter coupled to the reciprocator to reciprocate with it, configured to rotate about the central axis, and engaged with the undulating track; and a rotator engaged with the converter and configured to rotate about the central axis with the converter but not to linearly reciprocate along the central axis.

Abstract: Engines may include a piston, an undulating circumferential track, and a converter. In some examples, engines may include a body, a liner and a rotating cylinder. The body may have a cylindrical interior defining an axis and may include an inlet opening and an exhaust opening. The liner may be mounted within the cylindrical interior. The rotating cylinder may include a port that is sequentially aligned with the inlet and exhaust openings on the body as the rotating cylinder rotates within the body. The piston may be disposed within the rotating cylinder and configured for reciprocating motion along the axis. The converter may be mounted to the piston, engaged with the undulating circumferential track, and configured to reciprocate with the piston. The track may cause the converter to rotate about the axis as the converter reciprocates along the axis. The rotating cylinder may rotate with the converter.

Abstract: Systems for facilitating conversion between reciprocating linear motion and rotational motion include a continuous undulating track circumscribing a circular profile and generally defining a cylindrical volume having a central axis; a reciprocator that is configured to linearly reciprocate along the central axis; a converter coupled to the reciprocator to reciprocate with it, configured to rotate about the central axis, and engaged with the undulating track; and a rotator engaged with the converter and configured to rotate about the central axis with the converter but not to linearly reciprocate along the central axis.