Abstract: A fluid pressure, free piston engine, such as a centrifugal piston expander, provides a cyclically varying torque to a rotatable output shaft. A unidirectional or overrunning rotational clutch comprising two relatively rotatable elements has one element secured to a unidirectionally rotatable load and the other element driven by the output shaft of the centrifugal piston expander. The engine output shaft further drives, through appropriate gearing, a battery operated, starting motor-generator unit. The motor-generator is employed to initially rotate the expander to sufficient speed to ensure the centrifugal return of the free pistons of the centrifugal piston expander to their radially outermost positions. After start-up of the centrifugal piston expander, the starting motor functions as a generator to recharge the battery during the high torque portions of rotation of the engine output shaft, and during the low torque portions of the power output shaft, again functions as a motor to increase such speed.

Abstract: A method and apparatus for extracting heat and mechanical energy from a pressured gas utilizes a plurality of peripherally spaced cylinders fixedly mounted in generally tangential relationship about a rotatable power output shaft. A unidirectional clutch is mounted on the shaft and the pistons provided for each cylinder are respectively provided with pivoted connecting rod connections to the outer housing of the unidirectional clutch so that movement of the pistons from the outer ends of the cylinders toward the inner ends will effect rotation of the output shaft, while reverse movement of the pistons in the cylinders will have no effect on the rotation of the output shaft. The cylinders are preferably mounted in a cylindrical wall of a hollow housing defining a sealed internal fluid pressure chamber communicating with the inner ends of each of the cylinders.

Abstract: Apparatus for producing a reciprocating oscillation of a power output shaft comprises a plurality of peripherally spaced cylinders disposed in generally tangential relationship to the periphery of a cylindrical fluid pressure chamber and connected at their inner ends to such fluid pressure chamber. The gas pressure in such chamber is regulated to maintain a selected value above ambient. Cooperating pistons in each of the cylinders are interconnected by connecting rods to a spoke-like rocker element which is freely oscillatable about the output shaft to which the housing defining the cylindrical fluid pressure chamber is secured for co-rotation. A flywheel mass is connected to the spokes of the rocker element. Inlet and exhaust valves are provided in a cylinder head mounted in the outer end of each cylinder and are operable by contact with the outer face of the respective piston.

Abstract: Method and apparatus for producing rotation of a power output shaft comprises a plurality of peripherally spaced cylinders disposed in generally tangential relationship to the periphery of a housing defining a cylindrical fluid pressure chamber and connected at their inner ends to such fluid pressure chamber. The housing is mounted on, and co-rotatable with the output shaft. The gas pressure in such chamber is regulated to maintain a selected value above ambient. Cooperating pistons in each of the cylinders are interconnected by connecting rods to a unidirectional clutch mounted in the fluid pressure chamber on a fixed shaft, thus forcing the cylinders to rotate when pressured gas is introduced in the outer ends of the cylinders. Inlet and exhaust valves are provided in a cylinder head mounted in the outer end of each cylinder and are operable by contact with the outer face of the respective piston.