Stabilized free-piston stirling cycle machine

A free piston Stirling cycle machine, comprising:

• a displacer cylinder having a central cylindrical axis;
• a displacer located within the displacer cylinder and movably mounted along the axis;
• an enclosed gas spring;
• working gas means including an enclosed volume of pressurized working gas directed to opposite axial ends of the displacer for cyclically reciprocating the displacer along its axis in a Stirling cycle mode of operation;
• a displacer drive rod fixed to the displacer;
• counterbalance means movably mounted for reciprocating motion coaxially with the displacer;
• stabilizer means mechanically coupled to the counterbalance means for cyclically constraining reciprocating axial motion of the counterbalance means in a repetitive pattern;
• hydrostatic fluid means operably coupling the counterbalance means to the gas spring for accommodating fluid volumetric displacement due to engine operation, the hydrostatic fluid means also being operably connected between the displacer drive rod and counterbalance means for imparting equal and opposite axial movement to them;
• and
• movable power means for extraction of net cyclic work as a direct function of working gas pressure fluctuations.

A free piston Stirling cycle engine, comprising:

• a housing;
• a displacer cylinder formed in the housing and having a central cylindrical axis;
• a displacer located within the displacer cylinder, the displacer having an annular clearance seal formed about it that movably mounts the displacer within the displacer cylinder;
• an enclosed gas spring;
• working gas means including an enclosed volume of pressurized working gas directed to opposite sides of the annular clearance seal formed on the displacer for cyclically reciprocating the displacer along its axis in a Stirling cycle mode of operation;
• a coaxial displacer drive rod fixed to the displacer and movably guided in the housing by an annular clearance seal surrounding it;
• a coaxial counterbalance movably guided in the housing by an annular clearance seal surrounding it for reciprocating motion along the central cylindrical axis of the displacer;
• stabilizer means mechanically coupled to the counterbalance means for cyclically constraining reciprocating axial motion of the counterbalance means in a repetitive pattern;
• first hydrostatic fluid means operably coupling the counterbalance means to the gas spring for accommodating fluid volumetric displacement due to engine operation, the first hydrostatic fluid means also being operably connected between the displacer and counterbalance for imparting equal and opposite axial movement to them;
• and
• a power piston movable axially in response to cyclic changes in working gas pressure to thereby deliver net power externally to the engine.