233results about "Stirling type engines" patented technology

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 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 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 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 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.

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 thermoacoustic engine-generator that converts waste heat into electrical power. Thermal energy is converted to useful work via temperature-pressure amplification of periodic acoustic traveling waves in a compressible working fluid which cause the armature of a linear alternator to reciprocate and produce alternating current electrical energy. An external oscillator initiates reciprocating motion in the armature of a linear alternator. The armature is a combination fluid pump and fluid motor as well as the induction armature of a linear alternator. The pump end of the armature generates an acoustic traveling wave with each cycle of the armature. The traveling wave enters a waveguide-heat exchanger and is amplified in temperature, pressure and propagation velocity by thermal conduction of energy through the wall of the waveguide. The amplified traveling wave acts upon the opposite end of the armature, causing it to reciprocate within the magnetic field windings of the generator, and generate an electrical current as well as a new acoustic traveling wave. When the operating temperature gradient is attained across the hot and cold heat exchangers, the thermoacoustic engine-generator becomes acoustically resonant and self-regenerative, and will continue to operate as long as the thermal gradient is maintained. The theoretical conversion efficiency is dependent on the thermal gradient, and is 63% of Carnot.

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.

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.

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.

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 resonator has an asymmetrical, round configuration which enhances the cooling power of the thermoacoustic refrigerator.