Stirling engine compressor with compressor and engine working fluid equalization

A free-piston Stirling engine/compressor, comprising:

• a hermetic vessel enclosing an engine working space adapted to contain a working gas;
• a heater for heating the working gas and a cooler for cooling the working gas;
• a regenerator for extracting and storing heat from the working gas as it flows in one direction, and returning the heat to the working gas as it flows in the other direction;
• a displacer reciprocally mounted in said working space to displace a working gas between said heater and said cooler through said regenerator to create a pressure wave in said working gas;
• a compressor space;
• a sealed hydraulic chamber in said vessel closed at one end by an engine diaphragm which is exposed to said pressure wave and closed at the opposite end by a compression diaphragm which is disposed adjacent said compression space;
• a power piston reciprocally mounted within said hydraulic chamber so as to divide said chamber into two volumes, one of which volume is defined by one face of said power piston and said engine diaphragm and the other volume being defined by the opposite face of said power piston and said compression diaphragm;
• an inlet valve and an exhaust valve communicating between said compression space and a suction plenum and an exhaust plenum, respectively;
• control means communicating with said compression space and said working space for adjusting the mean pressure in said working space to maintain a predetermined proportional relationship between the mean pressure in said compression space and the mean pressure in said working space.