Abstract: A fuel injector for a liquid fuel burner that provides for large turn-down ratios and low firing rates. The fuel injector has a fast acting valve to provide a pulsed flow of fuel from a fuel supply and a nozzle coupled to the valve for receiving and atomizing the pulsed flow of fuel. The pulse of atomizing fuel is injected into the throat of a burner. A fuel controller coupled to the fuel supply and the fuel injector governs the rate of fuel delivery by controlling the duration and frequency of an opening period of the fast acting valve.

Abstract: A method for controlling the fuel-air ratio of a burner having a blower responsive to a blower drive signal for injecting air into the burner. The method is based at least on the concentration of a gas in an exhaust gas product of a combustion chamber of the burner and includes measuring the gas concentration in the exhaust gas product, deriving a gas concentration signal from the measured gas concentration, determining the fuel-air ratio from the gas concentration signal and the sign of the derivative of the gas concentration signal with respect to the blower drive signal, and controlling the fuel-air ratio by adjusting the air flow rate into the burner. The burner may be, for example, in a Stirling cycle engine.

Abstract: A device and method for controlling the flow of a gaseous fuel from a fuel supply to a pressurized combustion chamber. A fuel pump is included in the gas train from supply to chamber. The fuel pump increases the pressure of the gas to allow efficient injection into the chamber. The pump is modulated to control the fuel flow. Both alternating current and pulse-width-modulated direct current signals may be used to control the flow. The pump may be a piston pump or a diaphragm pump. Feedback may be provided from sensors that determine operating parameters of the engine and such sensor signals may be used by the controller to maintain a parameter, such as temperature, at a specified value. An acoustic filter can be included in the gas train to significantly reduce gas flow pulsations generated by the pump. This filter improves the uniformity of the combustion process.

Abstract: A regenerator for a thermal cycle engine and methods for its manufacture. The regenerator has a random network of fibers formed to fill a specified volume and a material for cross-linking the fibers at points of close contact between fibers of the network. A method for manufacturing a regenerator has steps of providing a length of knitted metal tape and wrapping a plurality of layers of the tape in an annular spiral.

Abstract: A system for supporting lateral loads on a piston undergoing reciprocating motion along a longitudinal axis in a cylinder includes a guide link for coupling the piston to a crankshaft undergoing rotary motion about a rotation axis of the crankshaft where the longitudinal axis and the rotation axis are substantially orthogonal to each other. A first guide element is located along the length of the guide link and includes a spring mechanism for urging the first guide element into contact with the guide link. The spring mechanism includes a first spring with a first natural frequency of oscillation and a second spring with a second natural frequency of oscillation. A second guide element is in opposition to the first guide element.

Abstract: A regenerator for a thermal cycle engine and methods for its manufacture. The regenerator has a random network of fibers formed to fill a specified volume and a material for cross-linking the fibers at points of close contact between fibers of the network. A method for manufacturing a regenerator has steps of providing a length of knitted metal tape and wrapping a plurality of layers of the tape in an annular spiral.

Abstract: A regenerator for a thermal cycle engine and methods for its manufacture. The regenerator has a random network of fibers formed to fill a specified volume and a material for cross-linking the fibers at points of close contact between fibers of the network. A method for manufacturing a regenerator has steps of providing a length of knitted metal tape and wrapping a plurality of layers of the tape in an annular spiral.

Abstract: An external combustion engine having an exhaust flow diverter for directing the flow of an exhaust gas. The external combustion engine has a heater head having a plurality of heater tubes through which a working fluid is heated by conduction. The exhaust flow diverter is a cylinder disposed around the outside of the plurality of heater tubes and includes a plurality of openings through which the flow of exhaust gas may pas. The exhaust flow diverter directs the exhaust gas past the plurality of heater tubes. The external combustion engine may also include a plurality of flow diverter fins coupled to the plurality of heater tubes to direct the flow of the exhaust gas. The heater tubes may be U-shaped or helical coiled shaped.

Abstract: An auxiliary power system for providing electrical power and heat to an indoor area includes an external combustion engine, such as a Stirling cycle engine, for generating mechanical energy and thermal energy. The external combustion engine burns a fuel with substantially complete combustion such that exhaust emissions from the external combustion engine are below a predetermined exhaust level. A generator is coupled to the external combustion engine and converts the mechanical energy produced by the external combustion engine to electrical power. A first power output is used to provide the electrical power produced by the generator. The external combustion engine and generator are disposed within a housing such that the external combustion engine, generator and housing combination is a portable size. The thermal energy generated by the external combustion engine may be used to heat the atmosphere surrounding the housing.

Abstract: A thermal cycle engine having a heat exchanger for transferring thermal energy across the heater head from a heated external fluid to the working fluid. The heat exchanger has a set of heat transfer pins each having an axis directed away from the cylindrical wall of the expansion cylinder, or, alternatively, a set of fins substantially aligned with the axis of the expansion cylinder. The height and density of the heat transfer pins may vary with distance in the direction of the flow path, and the pin structure may be fabricated by stacking perforated rings in contact with a heater head. A ring burner supplements the main combustor for supplying additional fuel to cause additional combustion of the exhaust gas. A regenerator for the thermal cycle engine has a random network of fibers formed to fill a specified volume and a material for cross-linking the fibers at points of close contact between fibers of the network.

Abstract: A method for controlling the fuel-air ratio of a burner having a blower responsive to a blower drive signal for injecting air into the burner. The method is based at least on the concentration of a gas in an exhaust gas product of a combustion chamber of the burner and includes measuring the gas concentration in the exhaust gas product, deriving a gas concentration signal from the measured gas concentration, determining the fuel-air ratio from the gas concentration signal and the sign of the derivative of the gas concentration signal with respect to the blower drive signal, and controlling the fuel-air ratio by adjusting the air flow rate into the burner. The burner may be, for example, in a Stirling cycle engine.

Abstract: A folded linkage for coupling a crankshaft and a piston undergoing reciprocating linear motion along a longitudinal axis. The folded linkage has a guide link with a first end coupled to the piston. A connecting rod couples the distal end of the guide link to the crankshaft which rotates about an axis that is orthogonal to the longitudinal axis of piston motion and located between the proximal end and the distal end of the guide link. A guide link guide assembly supports lateral loads on the guide link at its distal end. The folded linkage may be applied to couple the compression piston and displacer piston of a Stirling cycle machine to a common crankshaft.

Abstract: A method of combusting fuel and air in a burner of an external combustion engine having a heater head. The fuel and air are combined to form a fuel-air mixture which is characterized by a fuel-air ratio. An exhaust gas product is produced when the fuel-air mixture is combusted in the burner of the external combustion engine. A flame is formed by igniting the fuel-air mixture at a first fuel-air ratio produced by a first air flow rate and a fuel flow rate. The air flow rate is then increased to produce a second fuel-air ratio. The fuel flow rate is also controlled based upon a temperature of the heater head of the external combustion engine. The flame is maintained at the second fuel-air ratio by adjusting the air flow rate based on the fuel flow rate. The external combustion engine may be, for example, a Stirling cycle engine.

Abstract: A Stirling machine having two pistons coupled to a harmonic crank drive linkage for providing a specified phase relationship between sinusoidal displacements of each piston with respect to a fixed fiducial point. The harmonic crank drive linkage has a primary crankshaft and an eccentric crankshaft mounted internally to the primary crankshaft and coupled via a gear set to counterrotate with respect to the primary crankshaft. The eccentric crankshaft may be cantilevered with respect to the primary shaft, with the pistons of the engine coupled to the eccentric crankshaft externally to the supporting bearings. A flywheel coupled to the eccentric crankshaft provides for operation of the engine with a zero net angular momentum. An intake manifold provides for mixing air and fuel for combustion heating of the engine.