Patent ID: 7171811
Filing Date: 2007-02-06
Classification: F02G

Abstract:
1. An improved, free-piston, alpha configuration, Stirling machine having at least three pistons and at least three cylinders, each piston reciprocatable in a mating cylinder, each piston and cylinder bounding an expansion space and a compression space in each cylinder, the expansion space in each cylinder being series connected in an alpha Stirling configuration through a regenerator to a compression space in another cylinder and the compression space in each cylinder being series connected in an alpha Stirling configuration through a regenerator to the expansion space in another cylinder, wherein the improvement comprises: (a) each cylinder being a stepped cylinder having a relatively larger diameter interior wall and a coaxial, relatively smaller diameter interior wall; (b) each piston being a stepped piston comprising (c) one of said end faces of each piston bounding the compression space in the cylinder in which the piston reciprocates and the other said end face of each piston bounding the expansion space in the cylinder in which the piston reciprocates.