Patent ID: 8726857

Claim:
A device for generating electrical energy using a thermal cycle of a working gas, the device comprising: at least one piston movably mounted in a container to form a working chamber between the at least one piston and the container, the working chamber containing the working gas performing the thermal cycle; an electrical circuit mounted stationary relative to the container, the electrical circuit being electromagnetically coupled to provide a motive force to the at least one piston; an electronic power converter electrically connected to the electrical circuit and to an electrical bus; an electrical storage device electrically connected to the electrical bus; the at least one piston being movably mounted such that its motion electromagnetically induces current in the electrical circuit; and an electronic controller electronically connected to the electronic power converter to control motion of the at least one piston to perform, in the thermal cycle, at least one of: (i) expanding the working gas beyond the volume at which compression of the working gas is begun within the thermal cycle or (ii) exhausting the working gas to a remaining volume less than the smallest volume of compressed gas within the thermal cycle; the electronic controller being further electronically connected to the electrical bus to control both (i) flow of electrical energy produced by the current induced in the electrical circuit to the electrical bus, and (ii) flow of electrical energy from the electrical bus to the electrical circuit to electromagnetically provide the motive force to the at least one piston, and to effect a net positive average power transfer from the working gas to the electrical bus over the course of the thermal cycle; the working chamber comprising a single orifice for the intake and exhaustion of working gas.