Abstract: A free-piston Stirling engine includes a hermetically sealed vessel enclosing a working space within which reciprocates a displacer. The displacer is mounted at its cold end on mounting means including a first portion, preferably a post, which reciprocates in a second portion, preferably a sleeve, fixed to the vessel. The relatively reciprocating mounting means includes a gas spring. The mounting means also reduces the effective area exposed to a pressure wave of the displacer cold end relative to the displacer hot end so that the thermodynamic system provides power by virtue of the differential areas of the displacer ends. The periodic pressure wave together with the gas spring maintain the displacer in oscillation.

Abstract: A phase and stroke control apparatus for the pistons of a Stirling engine includes a ring on the end of each piston rod in which a pair of eccentrics is arranged in series, torque transmitting relationship. The outer eccentric is rotatably mounted in the ring and is rotated by the orbiting ring; the inner eccentric is mounted on an output shaft. The two eccentrics are mounted for rotation together within the ring during normal operation. A device is provided for rotating one eccentric with respect to another to change the effective eccentricity of the pair of eccentrics. A separately controlled phase adjustment is provided to null the phase change introduced by the change in the orientation of the outer eccentric, and also to enable the phase of the pistons to be changed independently of the stroke change.

Abstract: A free piston Stirling engine includes a hermetically sealed vessel enclosing a working space which is filled with a working gas such as helium. A displacer is mounted in the working space on a suspension apparatus for axial reciprocation to displace working gas back and forth sequentially through a heater, a regenerator, and a cooler to create a cyclic pressure wave which drives a power piston. The displacer is connected to a mounting flange fixed to the vessel by a bellows which permits the displacer to move axially. A diaphragm is connected to the mounting flange and seals an oil cavity whose sides are defined by the bellows. The top of the oil cavity is formed by a transverse wall in the displacer, in which is formed a cylinder which receives a stationary piston mounted on a spider in the oil cavity and fastened to the mounting flange.

Abstract: A diaphragm suspension system for a free piston Stirling engine includes a transverse wall across the cold end of the displacer. An upper diaphragm is attached to the displacer shell above the transverse wall, and a support diaphragm is attached at its center to a partition fixed to the engine vessel, and is attached at its peripheral edge to the lower end of the displacer. A lower oil cavity is defined between the transverse wall and the support diaphragm, and an upper oil cavity is defined between the upper diaphragm and the transverse wall. A cylinder is formed in the transverse wall communicating between the oil cavities, and a piston is disposed in the cylinder and is fixed to the partition. When the displacer moves, the piston remains stationary and compensates for the oil displacement caused by the support diaphragm flexing into and out of the oil cavity, so the support diaphragm experiences only or primarily displacement induced stress rather than pressure induced stress.

Abstract: A free piston Stirling engine having a hermetically sealed vessel enclosing a working space which can be charged with a working gas under pressure. A displacer, mounted in the working space at the cold end by a spring diaphragm member, to circulate the working gas through a heater, a regenerator, and a cooler to create a pressure wave in the working gas which acts against a power piston to produce output power. The spring diaphragm member provides an effective decrease in the area of the cold end of the displacer which causes the thermodynamic system to provide motive power for maintaining the oscillation of the displacer, supports and centers the displacer in the working space, and functions as a spring to return the displacer towards its center position when it is displaced toward the cold or hot end.

Abstract: A free piston Stirling engine having a free displacer mounted in a sealed vessel and suspended on a diaphragm. A rigid wall on the displacer forms, with the diaphragm, a closed oil cavity. A moving wall such as a piston or bellows in the rigid wall accommodates volmetric changes in the cavity when the displacer oscillates in the engine working space to control pressure induced stresses in the diaphragm.

Abstract: A reciprocating-to-rotating motion conversion and power control device for a Stirling engine includes a hub mounted on an offset portion of the output shaft for rotation relative to the shaft and for sliding motion therealong which causes the hub to tilt relative to the axis of rotation of the shaft. This changes the angle of inclination of the hub relative to the shaft axis and changes the axial stroke of a set of arms connected to the hub and nutating therewith. A hydraulic actuating mechanism is connected to the hub for moving its axial position along the shaft. A balancing wheel is linked to the hub and changes its angle of inclination as the angle of inclination of the hub changes to maintain the mechanism in perfect balance throughout its range of motion.

Abstract: A heat exchanger system for a Stirling engine includes a heater connected to the expansion space by a pair of parallel flow ducts, and a cooler connected to the compression space by a pair of parallel flow ducts. A circulator is arranged in one of the heater ducts and one of the cooler ducts to continuously circulate working fluid from the working space, through the heat exchanger, and back into the same working space. The expansion and compression processes are thereby made more isothermal and the heat exchangers may be made smaller, more effective and with a lower pressure drop.

Abstract: A Rankine cycle turbine drives an electric generator and a feed pump, all on a single shaft, and all enclosed within a hermetically sealed case. The shaft is vertically oriented with the turbine exhaust directed downward and the shaft is supported on hydrodynamic fluid film bearings using the process fluid as lubricant and coolant. The selection of process fluid, type of turbine, operating speed, system power rating, and cycle state points are uniquely coordinated to achieve high turbine efficiency at the temperature levels imposed by the recovery of waste heat from the more prevalent industrial processes.

Abstract: A free-piston Stirling engine compressor includes a hermetic vessel enclosing a working space in which a displacer reciprocates for displacing working gas through a heater, regenerator and a cooler so as to create a pressure wave. The pressure wave acts on an engine diaphragm to displace fluid in an adjacent hydraulic chamber to drive a power piston on a power stroke. The power piston acts in the hydraulic chamber against an adjacent compressor diaphragm to compress a gas in a compression space and expell the compressed gas through an exhaust valve. A control system is provided for adjusting the mean pressure in the engine working space to maintain a predetermined proportional relationship between the mean pressure in the compression space and the engine working space.

Abstract: A method and apparatus for controlling a resonant piston compressor of the type comprising an electrodynamic linear reciprocating motor adapted to be driven cyclically by an alternating current power source and having at least one piston coupled to and adapted to be driven within a selectively valved working cylinder by the linear reciprocating motor in synchronism with the frequency of the alternating current power source. Enclosed volumes of gas act as resilient gas springs coacting with the piston and with the linear reciprocating motor to form a mechanical resonant system having a resonant frequency substantially centered on the frequency of the alternating current power source. A midstroke porting arrangement is responsive to the position of the resonant piston for selectively communicating a gas spring control valve with said gas springs.

Abstract: A gaseous fuel combustor for a Stirling engine includes a shell mounted on the engine, and air inlet and exhaust ports formed in the shell. An annular cylindrical recuperator communicates with the inlet and exhaust ports for preheating the combustion air with the heat from the exhaust. An annular burner surrounds the dome shaped engine heater head for mixing gaseous fuel with the air and burning it at the outer peripheral edge of the heater head. The combustion products converge upwardly in a narrow space between a ceramic partition and the heater head dome so that the heat flux is constant. The combustion products exhaust through a axial hole in the center of the ceramic partition and travel back outward over the top of the partition to the annular recuperator.

Abstract: A free-piston Stirling engine usable as a heat pump has a closed vessel filled with helium working gas which is heated at the bottom end and cooled at the top end. The vessel contains a displacer supported for axial reciprocal oscillation on a gas spring post mounted on the vessel. The displacer shuttles the working gas from end to end in the vessel, alternately heating and cooling the gas. The vessel is sealed with a flexible diaphragm which flexes in response to the pressure wave generated in the vessel as the working gas is alternately heated and cooled. When the diaphragm flexes, it displaces hydraulic fluid in a hydraulic chamber and drives a power piston for driving a linear alternator and a gas compressor. A gas spring operating on a second hydraulic cylinder on the other side of the power piston stores part of the energy of the piston stroke and returns it for the return stroke.

Abstract: A linear electrodynamic machine is disclosed having permanent magnet excitation and an end flux leakage control. A flux carrying body having a plurality of annular magnets of alternating radially oriented polarities is disposed concentrically with respect to a stator having a plurality of annular wound coils. Relative axial reciprocation of the body and stator causes a reversal of the flux linking the coils while the flux in the body remains substantially constant. Focusing magnets provided on each end of the body and axial extensions provided on the stator insure uniformity of the alternating flux linking the coils and a constant flux intensity in the body to achieve high efficiencies.

Abstract: A free-piston Stirling engine usable as a heat pump has a closed vessel filled with helium working gas which is heated at the bottom end and cooled at the top end. The vessel contains a displacer supported for axial reciprocal oscillation on a gas spring post mounted on the vessel. The displacer shuttles the working gas from end to end in the vessel, alternately heating and cooling the gas. The vessel is sealed with a flexible diaphragm which flexes in response to the pressure wave generated in the vessel as the working gas is alternately heated and cooled. When the diaphragm flexes, it displaces hydraulic fluid in a hydraulic chamber and drives a power piston for driving a linear alternator and a gas compressor. A gas spring operating on a second hydraulic cylinder on the other side of the power piston stores part of the energy of the piston stroke and returns it for the return stroke.

Abstract: A lip seal for preventing the mixing of seawater with an oil cavity around a marine stern tube includes an annular radial flange attached to one end of an axially extending bushing which is encircled by a garter spring. An axially extending foot projects from the bushing into the oil cavity and includes a hydrodynamic profile on its inner surface. A pocket is formed in the sealing face of the bushing and is pressurized with oil by the hydrodynamic profile on the bushing. The pressurized oil pocket balances the water pressure on the outside of the seal, and the hydrodynamic profile forms a fluid film which lubricates the seal and provides the balancing pressure for the pocket. A series of vents can be provided to vent excess oil pressure in the pocket to prevent leakage of oil out of the pocket into the water.