A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

A Stirling cycle machine with a liquid fuel/gaseous fuel burner. The burner may include a preheater to capture the thermal energy of the exhaust. The burner directs the preheated air to each burner head, where it enters a prechamber. Each burner head includes a fuel nozzle that directs liquid or gaseous fuel into the prechamber. The prechamber is fluidically connected to a combustion chamber via a prechamber nozzle that has a smaller opening than the prechamber. The burner head ignites the fuel air mixture in the prechamber with an ignitor located above or within the prechamber. The flame is initially lit as a diffusion flame in the prechamber. The flame is pushed out of the prechamber into the combustion chamber by an increased air flow rate. The liquid fuel from the nozzle now evaporates in the prechamber and forms a prevaporized flame in the combustion chamber.

A novel engine for producing power from a temperature differential with additional benefits of low cost, high efficiency, quiet operation minimal wear of components, and the ability to produce power or cooling from low grade heat sources.

A monolithic heat exchanger body for inputting heat to a closed-cycle engine includes heating walls and heat sink, such as heat transfer regions. The heating walls are configured and arranged in an array of spirals or spiral arcs relative to a longitudinal axis of an inlet plenum. Adjacent portions of the heating walls respectively define corresponding heating fluid pathways fluidly communicating with the inlet plenum. At least a portion of the heat sink is disposed about at least a portion of the monolithic heat exchanger body. The heat sink includes working-fluid bodies including working-fluid pathways that have a heat transfer relationship with the heating fluid pathways. Respective ones of the heat transfer regions have a heat transfer relationship with a corresponding semiannular portion of the heating fluid pathways. Respective ones of the heat transfer regions include working-fluid pathways fluidly communicating between a heat input region and a heat extraction region.

A constant density heat exchanger and method of operating are provided. The constant density heat exchanger includes a housing extending between a first end and a second end and defining a chamber having an inlet and an outlet. A first plate is positioned at the first end of the housing and rotatable about an axis of rotation such that the first plate selectively allows a working fluid to flow into the inlet of the chamber. A second plate is positioned at the second end of the housing and rotatable about the axis of rotation such that the second plate selectively allows the working fluid to flow out of the outlet of the chamber. The first plate and the second plate are rotatable about the axis of rotation so as to hold a volume of the working fluid at constant density as a heat source imparts thermal energy thereto.

An energy conversion device includes a first acoustic wave generator, a second acoustic wave generator, and an output unit which are provided in a pipe member. The first acoustic wave generator has a thermal energy generator configured to generate thermal energy from electric energy, and converts the thermal energy generated by the thermal energy generator into acoustic energy to generate acoustic wave in working gas by a self-excited thermo acoustic vibration. The second acoustic wave generator converts thermal energy supplied from a heat supply source into acoustic energy and generates acoustic wave in working gas by a self-excited thermo acoustic vibration. The output unit converts the acoustic energy of the acoustic waves from the first acoustic wave generator and the second acoustic wave generator into cold energy to output.

A Stirling engine feedback controller is provided that includes a Stirling engine having at least one piston, where the Stirling engine includes an Alpha-Stirling engine, and a Gamma-Stirling engine. The feedback controller includes a power sensor, a computer, and an electronic feedback loop. Here, the power sensor is configured to sense the power of the Stirling engine then output a power signal. In one aspect, the computer can be a central processing unit (CPU), or a field programmable gate array (FPGA), where the computer operates a control algorithm. Further, the electronic feedback loop receives the output power signal and an output signal from the computer, where an output signal from the electronic feedback loop is configured to a control a position of the piston(s).

A voice-coil type cooler motor magnet assembly includes at least one radially polarized ring magnet disposed on a ferromagnetic hub. At least one quadrature magnet is disposed on the hub on each longitudinal side of the at least one ring magnet. Each quadrature magnet is polarized in a direction toward the at least one ring magnet. The hub, the at least one radially polarized ring magnet and the quadrature magnets are disposed in a ferromagnetic outer housing.

A free-piston Stirling engine that limits piston amplitude and reduces engine power as the piston amplitude increases beyond its maximum power. The inward edge of the heat rejecter cylinder port is located outward of the most inward excursion of the inward end of the piston sidewall during a part of the piston's reciprocation cycle so that the heat rejecter cylinder port is entirely covered by the piston sidewall during an inward portion of the piston reciprocation when the engine is operating at the selected maximum engine power. A leaker port extends from a gas bearing cavity through the piston sidewall and is positioned axially outward from the gas bearing pads of the engine's gas bearing system and vents working gas to the engine's back space at a piston amplitude of reciprocation that exceeds the piston's amplitude of reciprocation at maximum engine power. A resilient damping bumper is attached to the outward end of the piston and a displacer gas cushion is disclosed.

A free-piston Stirling engine that limits piston amplitude and reduces engine power as the piston amplitude increases beyond its maximum power. The inward edge of the heat rejecter cylinder port is located outward of the most inward excursion of the inward end of the piston sidewall during a part of the piston's reciprocation cycle so that the heat rejecter cylinder port is entirely covered by the piston sidewall during an inward portion of the piston reciprocation when the engine is operating at the selected maximum engine power. A leaker port extends from a gas bearing cavity through the piston sidewall and is positioned axially outward from the gas bearing pads of the engine's gas bearing system and vents working gas to the engine's back space at a piston amplitude of reciprocation that exceeds the piston's amplitude of reciprocation at maximum engine power. A resilient damping bumper is attached to the outward end of the piston and a displacer gas cushion is disclosed.