Abstract: A working gas control system for a double acting type Stirling engine having two or more piston assemblies reciprocating within bores. Each of the piston assemblies separate isolated cycle volumes of a working gas which undergoes cyclical pressure variations. The pressure equalization system includes forming isolated first and second volumes with the first volume maintained at a low pressure through the use of a check valve. The second volume is maintained at a pressure intermediate of the minimum and maximum pressures of the cycle volumes. By providing controlled leakage paths between the volumes, the mass or volume of working gas in each of the cycle volumes can be maintained in a balanced condition despite minor leakages outside the engine of the working gas and leakage past the piston assemblies separating the cycle volumes.

Abstract: A control valve for a double acting type Stirling engine of the type having two or more piston assemblies reciprocating in bores with each of the piston assemblies separating isolated volumes of a working gas. The control valve provides the functions of a check valve which allows an internally defined volume within the engine to be held at a low pressure near the minimum pressure of the cycle volumes. The valve may further be actuated to unload the engine to provide low starting torque and to unload the engine in case of an engine or load malfunction. The control valve further provides a controlled leakage path for working fluid flowing between the cycle volumes and the minimum pressure volume which acts as part of a pressure balancing system for the Stirling engine which maintains the volume or mass of a working fluid in a balanced condition between the cycle volumes.

Abstract: A rod seal assembly for a Stirling Engine of the type having two or more piston assemblies reciprocating within cylinder bores. The rod seal assembly seals against a connecting rod extending between a piston and a kinematic drive system. The rod seal assembly includes a separated cap seal assembly and a base seal assembly with a hollow cavity formed therebetween. The cap seal assembly and base seal assembly include sealing element features which provide high performance gas sealing and excellent durability characteristics. The hollow interior cavity of the rod seal assembly may be used as part of an internal volume within the engine used as part of a pressure balancing system for the isolated cycle volumes within the engine.