233results about "Stirling type engines" patented technology

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

The invention describes devices for performing thermodynamic work on a fluid, such as pumps, compressors and fans. The thermodynamic work may be used to provide a driving force for moving the fluid. Work performed on the fluid may be transmitted to other devices, such as a piston in a hydraulic actuation device. The devices may include one or more electroactive polymer transducers with an electroactive polymer that deflects in response to an application of an electric field. The electroactive polymer may be in contact with a fluid where the deflection of the electroactive polymer may be used to perform thermodynamic work on the fluid. The devices may be designed to efficiently operate at a plurality of operating conditions, such as operating conditions that produce an acoustic signal above or below the human hearing range. The devices may be used in thermal control systems, such as refrigeration system, cooling systems and heating systems.

The present invention relates to electroactive polymers that are pre-strained to improve conversion from electrical to mechanical energy. When a voltage is applied to electrodes contacting a pre-strained polymer, the polymer deflects. This deflection may be used to do mechanical work. The pre-strain improves the mechanical response of an electroactive polymer. The present invention also relates to actuators including an electroactive polymer and mechanical coupling to convert deflection of the polymer into mechanical work. The present invention further relates to compliant electrodes that conform to the shape of a polymer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

Present implementations provide an approach that allows for a double-acting, multi-cylinder, thermodynamically resonant, alpha configuration free-piston Stirling system. The system includes overstroke preventers that control extent of piston travel to prevent undesirable consequences of piston travel beyond predetermined limits. The overstroke preventers involve controlled work extraction out of the system or controlled work input into the system. Implementations can also include duplex linear alternators, and / or frequency tuning systems, and / or vibration balancing configurations.

The invention describes devices for controlling fluid flow, such as valves. The devices may include one or more electroactive polymer transducers with an electroactive polymer that deflects in response to an application of an electric field. The electroactive polymer may be in contact with a fluid where the deflection of the electroactive polymer may be used to change a characteristic of the fluid. Some of the characteristic of the fluid that may be changed include but are not limited to 1) a flow rate, 2) a flow direction, 3) a flow vorticity, 4) a flow momentum, 5) a flow mixing rate, 6) a flow turbulence rate, 7) a flow energy, 8) a flow thermodynamic property. The electroactive polymer may be a portion of a surface of a structure that is immersed in an external fluid flow, such as the surface of an airplane wing or the electroactive polymer may be a portion of a surface of a structure used in an internal flow, such as a bounding surface of a fluid conduit.

A sonic actuator including a multi-layer membrane having a non-metallic elastomeric dielectric polymer layer with a first surface and a second surface, a first compliant electrode layer contacting the first surface of the polymer layer, and a second compliant electrode layer contacting the second surface of the polymer layer. The actuator further includes a support structure in contact with the sonic actuator film. Preferably, the non-metallic dielectric polymer is selected from the group consisting essentially of silicone, fluorosilicone, fluoroelastomer, natural rubber, polybutadiene, nitrile rubber, isoprene, and ethylene propylene diene. Also preferably, the compliant electrode layer is made from the group consisting essentially of graphite, carbon, and conductive polymers. The support structure can take the form of grid having a number of circular apertures. When a voltage is applied to the electrodes, portions of the film held at the aperture of the support structure can bulge due to the electrostriction phenomenon. The resultant “bubbles” can be modulated to generate sonic vibrations, or can be used to create a variable surface for airflow control.

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

A standing wave pump in which a standing compression wave is produced by a pair of diametrically opposing transducers. The vibrating surfaces of the transducers are oscillated at a frequency sufficient to generate a substantially cylindrical compression wave having substantially planar wave fronts between the transducer pair. The length of pump housing is made to be equal to an integer times half the wavelength of the compression wave and the pump housing acts as a resonant cavity having a standing wave pattern set up in it. Waves are simultaneously produced and reflected by the oscillating surface and are superimposed upon one another and travel to the opposing oscillating surface where this process is repeated, substantially multiplying the intensity of the standing compression wave, which provides a stored-energy effect. The high-intensity standing compression wave has pressure nodes and antinodes, whose pressure differential is used to pump a medium through inlets and outlets advantageously located at the nodes and antinodes.

A thermoacoustic refrigerator having a relatively small size which utilizes one or more piezoelectric drivers to generate high frequency sound within a resonator at a frequency of between about 4000 Hz and ultrasonic frequencies. The interaction of the high frequency sound with one or more stacks create a temperature gradient across the stack which is conducted through a pair of heat exchangers located on opposite sides of each stack. The stack is comprised of an open-celled material that allows axial, radial, and azimuthal resonance modes of the resonator within the stack resulting in enhanced cooling power of the thermoacoustic refrigerator.

The present invention relates to transducers, their use and fabrication. The transducers convert between mechanical and electrical energy. Some transducers of the present invention include a pre-strained polymer. The pre-strain improves the conversion between electrical and mechanical energy. The present invention also relates to devices including an electroactive polymer to convert between electrical and mechanical energy. The present invention further relates to compliant electrodes that conform to the shape of a polymer included in a transducer. The present invention provides methods for fabricating electromechanical devices including one or more electroactive polymers.

An improved, free-piston, Stirling machine having at least three pistons series connected in an alpha Stirling configuration. Each cylinder is stepped so that it has a relatively larger diameter interior wall and a coaxial, relatively smaller diameter interior wall. Each piston is also stepped so that it has a first component piston having an end face facing in one axial direction and matingly reciprocatable in the smaller diameter cylinder wall and a second component piston having an end face facing in the same axial direction and matingly reciprocatable in the larger diameter, cylinder wall. One of the piston end faces bounds the compression space and the other end face bounds the expansion space. Preferably, each stepped piston has peripheral, cylinder walls that are axially adjacent and joined at a shoulder forming the end face of the larger diameter component piston. Stirling machines with these stepped features are also arranged in various opposed and duplex configurations, including arrangements with only one load or prime mover for each opposed pair of pistons. Improved balancing or vibration reduction is obtained by connecting expansion and compression spaces of a four cylinder in-line arrangement in a 1, 3, 2, 4 series sequence. Three cylinder embodiments provide a highly favorable volume phase angle of 120° and are advantageously physically arranged with three, parallel, longitudinal axes of reciprocation at the apexes of an equilateral triangle.

A thermoacoustic cooling system for cooling an object such as a microelectronic chip. Heat produced by the object is transferred to a thermoacoustic engine. The thermoacoustic engine may include a resonator defining a chamber. A stack may be positioned in the chamber with one side of the stack adjacent to the heat source, and the opposite side of the stack adjacent to air in the chamber having a relatively cooler temperature. One or more orifices may be formed in the resonator such that the acoustic power generated by the thermoacoustic engine creates a synthetic jet to circulate air and move the air away from the object being cooled. Thus, the heat produced by the object is used to power the thermoacoustic engine to thereby remove heat from the object. The thermoacoustic engine may use no moving parts and may require no external power source other than the object being cooled.

An improvement is provided to a pressurized close-cycle machine that has a cold-end pressure vessel and is of the type having a piston undergoing reciprocating linear motion within a cylinder containing a working fluid heated by conduction through a heater head by heat from an external thermal source. The improvement includes a heat exchanger for cooling the working fluid, where the heat exchanger is disposed within the cold-end pressure vessel. The heater head may be directly coupled to the cold-end pressure vessel by welding or other methods. A coolant tube is used to convey coolant through the heat exchanger.

A high-frequency, low-temperature regenerator (12). The regenerator (12) includes a substrate (50) having rare earth material (52) disposed thereon. In a specific embodiment, the substrate (50) has channels or pores (54) therethrough or therein to facilitate gas flow through the regenerator (12). The substrate (50) is constructed from a material, such as polyimide, polyester, or stainless steel, which is sufficient to define the geometry of the regenerator (12). The rare earth material (52) is selected and deposited on the substrate (50) in a layer (52) having thermal penetration depth that is greater than the thickness of the layer (52). The thermal penetration depth is sufficiently high to enable all of the rare earth material (52) to contribute to thermal regeneration at an operating frequency of 30 Hz. In the illustrative embodiment, the thickness of the substrate (50) is less than or equal to approximately 0.001 inches. The layer of rare earth material (52) is approximately 0.0002 inches thick. The substrate (44, 50) includes a stack of plated substrates (44) that are stacked so that spaces (54) exist between the plated substrates (44), which result in a porosity of approximately 15 percent. Dimples, pleats, or other mechanisms in the plated substrates (44) preserve the spaces (54) between the plated substrates (44). In the specific embodiment, the spaces (54) are approximately 0.00025 inches wide, and the working gas is helium.

To provide a Stirling engine and a control unit for a Stirling engine capable of disposing a displacer unit and a power cylinder unit separately from each other, thereby increasing the degree of freedom of layout thereof. A displacer unit and a power cylinder unit of a Stirling engine E are disposed separately from each other. A compression chamber of the displacer unit is connected to an operation chamber of the power cylinder unit via a pressure conduit. A control actuator capable of arbitrarily controlling the displacer piston of the displacer unit is connected to the displacer piston.

A multifuel internal combustion Stirling engine is described, wherein a compressor piston and a displacer piston reciprocate, within a common cylinder, to enclose a variable air volume, and a variable burned gas volume. Motion of these two pistons, creates a power producing cycle, of compression, combustion, expansion, and scavenge, wherein the burned gases do not contact those cylinder portions over which the compressor piston moves. In this way low engine wear can be obtained when using fuels such as coal, which produces abrasive particulates in the burned gases. A multifuel internal combustion engine of this invention can be readily adapted to operate on a wide variety of fuels, such as, natural gas, diesel fuel, residual petroleum fuel, and coal. Widespread use of these engines would introduce economic competition between these now separately competing fuels. This is a clear route to national energy independence, since coal reserves greatly exceed petroleum reserves, nationally and internationally.

Present implementations provide an approach that allows for a double-acting, multi-cylinder, thermodynamically resonant, alpha configuration free-piston Stirling system. The system includes overstroke preventers that control extent of piston travel to prevent undesirable consequences of piston travel beyond predetermined limits. The overstroke preventers involve controlled work extraction out of the system or controlled work input into the system. Implementations can also include duplex linear alternators, and / or frequency tuning systems, and / or vibration balancing configurations.

A thermocoustic device includes a housing with a thermal core supported in the housing and having a first and a second surface. The thermal core includes a first heat exchanger defining the first surface of the thermal core and a second heat exchanger defining the second surface of the thermal core. A main chamber is in fluid communication with the first surface of the thermal core and a secondary multiplier chamber is in fluid communication with the second surface of the thermal core. A working volume of a gaseous working fluid fills the main chamber, the multiplier chamber, and the thermal core at a pressure. An equilibrium pressure is defined as the pressure of the working volume of gaseous working fluids with the thermoacoustic device is in a non-operating mode. The main chamber includes a first oscillating member that is operable when the thermoacoustic device is in an operating mode to oscillate such that the pressure in both the main chamber and in the multiplier chamber is oscillated between a peak pressure greater than the equilibrium pressure and a minimum pressure less than the equilibrium pressure. A main pressure amplitude is defined as one-half of the difference between the peak pressure and the minimum pressure in the main chamber. The secondary multiplier chamber includes a second oscillating member that is operable when the thermoacoustic device is in the operating mode to oscillate such that the pressure in the multiplier chamber is oscillated between a peak pressure greater than the equilibrium pressure and a minimum pressure less than the equilibrium pressure. A multiplier pressure amplitude is defined as one-half of the difference between the peak pressure and the minimum pressure in the multiplier chamber. The first and second oscillating members oscillate at substantially the same frequency and such that the pressure oscillations in the main chamber and the multiplier chamber are substantially in phase with each other. The multiplier pressure amplitude is greater than the main pressure amplitude.

A personal vehicle for transporting a user over a surface including an external combustion engine. The vehicle includes a generator for converting the mechanical energy produced by the external combustion engine to electrical energy and an energy storage device for storing power provided by the generator and for providing power to the external combustion engine and the assembly. The personal vehicle includes a controller for controlling a total power load placed on the external combustion engine providing short term regulation of external combustion engine parameters.

A high-efficiency residential solar thermal power plant for economically generating power from solar-thermal energy, using a parabolic trough mirror having a longitudinal focal axis, for concentrating sunlight, a timer rotator for rotating the mirror about the focal and longitudinal rotation axis to follow the sun, and a heat collector surrounding a flow channel that preferably has an oblong cross-sectional shape with a major axis aligned with a longitudinal plane of symmetry of the parabolic trough mirror. The heat collector is coaxially positioned along the focal axis of said mirror to receive concentrated sunlight so that a working fluid is heated and provided for use through an outlet end of the heat collector.

The present invention provides a premixed charge compression ignition engine and control system (10), which can effectively trigger combustion and maintain stable combustion by means of compression ignition, while achieving extremely low nitrogen oxide emissions, good overall efficiency and Acceptable combustion noise and cylinder pressure. The engine and control system (10) of the present invention can effectively control the combustion process by controlling certain control variables of temperature control, pressure control, mixture self-ignitability control and equivalence ratio control, that is, the time of combustion initiation, the combustion rate , duration of combustion and / or completeness of combustion. The combustion control system (10) provides active feedback control of combustion and includes a sensor for detecting engine operating conditions representative of a combustion process, such as ignition of combustion, and generating a corresponding engine operating condition signal (18) , such as the pressure sensor (16).

A stirling cycle engine whose cylinder, including a mount, can be easily fabricated and securely attached. The stirling cycle engine of the invention comprises a casing having a cylindrical portion 2; a metallic cylinder 7 coaxially inserted into the cylindrical portion 2 of the casing 1; a piston 15 inserted into the cylinder 7; a drive mechanism 16 for reciprocally driving the piston 15; and a mount 28 which is attached to an outer periphery of the cylinder 7 for fixing the cylinder 7 to the casing 1 and retaining the drive mechanism 16. The mount 28 is made of a material of low heat conductance, constructed separately from the cylinder 7. The mount 28 is attached to the outer periphery of the cylinder 7. Thus, the easier working thereof is resulted, so that the working time is shortened, to thereby improve productivity, and reduce working costs. Further, The heat from the drive mechanism 16 is less likely to transfer to the cylinder 7 via the mount 28.