Gas bearing and method of making a gas bearing for a free piston machine
Granted: September 25, 2001
Patent Number:
6293184
A gas bearing structure including a cylindrical core and a cylindrical sleeve. The core has a radially outwardly facing surface with longitudinal and circumferential grooves formed thereon. The sleeve has a radially inwardly facing surface that sealingly abuts the outer core surface. The inwardly facing sleeve surface bridges over the grooves, defining fluid, preferably gas, flow paths within each groove. The gas flow paths permit gas to flow from the workspace to radial passages formed…
Method of fabricating a silicon solar cell
Granted: August 14, 2001
Patent Number:
6274402
A method of fabricating a back surface point contact silicon solar cell having p-doped regions and n-doped regions on the same side by forming a passivating layer on a surface of the cell having opened windows at the p-doped regions and the n-doped regions, by depositing and patterning a first metal layer on the passivating layer in such a way that the first metal layer comes into contact with the p-doped regions and the n-doped regions, by depositing a first insulator layer of inorganic…
DC centering of free piston machine
Granted: March 13, 2001
Patent Number:
6199381
In a free piston machine, a coil is mounted to its housing and magnetically linked to a permanent magnet or electromagnet on its piston member to form a linear motor. The coil and magnet are either added to embody the invention or are part of an AC linear alternator or AC linear motor which are a part of the free piston machine. A source of DC electrical current and a switch for connecting the DC source to the coil supply DC current to the coil when the switch is closed so that the coil…
Free piston internal combustion engine
Granted: January 9, 2001
Patent Number:
6170442
A free piston internal combustion engine having improved valve timing. A pair of oppositely disposed combustion chamber passageways extending between the combustion chamber and the earth's atmosphere, each have a combustion chamber valve for controlling the passage of gas through the passageways. The combustion chamber valves are essentially simultaneously opened and closed to permit independent variation and control of the compression ratio, expansion ratio, and stroke of the…
Refrigeration circuit having series evaporators and modulatable compressor
Granted: March 21, 2000
Patent Number:
6038874
A refrigeration system having a modulatable compressor and a Rankine cycle refrigeration circuit having at least two evaporators. The flow rate of the compressor is modulated in response to the sensed temperature of the masses being cooled, and the control circuit switches valves to control the refrigerant flow path and modulates the flow rate of the compressor to optimize the efficiency of the refrigeration system.
Free-piston internal combustion engine
Granted: March 14, 2000
Patent Number:
6035637
This invention is an efficient free-piston internal-combustion engine having an expansion ratio greater than the compression ratio and preferably with gas bearings supporting the piston. The use of gas bearings in combination with high-temperature ceramic materials allows the engine to be nearly adiabatic and with exhaust temperatures in excess of 600.degree. C. These high exhaust temperatures in turn allow the engine to operate as a topping cycle for gas turbines, Stirling engines,…
Centering system for free piston machine
Granted: February 23, 1999
Patent Number:
5873246
A centering apparatus for a free piston Stirling engine including a pressure regulator valve which connects a passageway between the work space and the back space when both (a) the average pressure in the back space exceeds the average pressure in the work space as a result of the piston deflecting a spring, and simultaneously (b) the instantaneous pressure in the back space exceeds the instantaneous pressure in the work space. A diaphragm spans across an actuator housing cavity,…
Free piston internal combustion engine
Granted: July 7, 1998
Patent Number:
5775273
A free piston internal combustion engine having improved valve timing. A pair of oppositely disposed combustion chamber passageways extending between the combustion chamber and the earth's atmosphere, each have a combustion chamber valve for controlling the passage of gas through the passageways. The combustion chamber valves are essentially simultaneously opened and closed to permit independent variation and control of the compression ratio, expansion ratio, and stroke of the engine.…
Refrigeration circuit having series evaporators and modulatable compressor
Granted: February 10, 1998
Patent Number:
5715693
A refrigeration system having a modulatable compressor and a Rankine cycle refrigeration circuit having at least two evaporators. The flow rate of the compressor is modulated in response to the sensed temperature of the masses being cooled, and the control circuit switches valves to control the refrigerant flow path and modulates the flow rate of the compressor to optimize the efficiency of the refrigeration system.
Refrigerator with interior mounted heat pump
Granted: July 1, 1997
Patent Number:
5642622
A refrigerator having a heat pump mounted within the insulated portion of the refrigerator cabinet which is cooled by the heat pump. The heat pump is a Stirling cycle or Rankine cycle heat pump, is used to cool the interior of the refrigerator cabinet, and is mounted in an insulated housing to limit the transfer of heat from the heat pump into the refrigerator cabinet. A heat transporting conduit connects the heat pump to an exterior heat exchanger mounted outside the refrigerator…
Magnet support sleeve for linear electromechanical transducer
Granted: June 24, 1997
Patent Number:
5642088
A reciprocating magnetic body support structure for a linear motor or a linear alternator is claimed. The body comprises a cylindrical, metallic support sleeve having a plurality of longitudinal slots evenly spaced around the circumference of the sleeve. An equal number of magnet segments is mounted to the sleeve extending over at least a portion of the associated slot and attaching to the wall of the sleeve on both sides of the associated slot. The longitudinal slots preferably extend…
Triac control circuit
Granted: January 7, 1997
Patent Number:
5592073
A common and inexpensive integrated 555 timing circuit is used to vary the timing of triac firing pulses in response to a control voltage. A trigger pulse generator generates a pulse at each zero cross-over of an AC line. This pulse initiates a variable, one shot pulse generator which generates a rectangular pulse. The rectangular pulse terminates following a time interval which is controlled by the magnitude of a control input signal. A pulse forming circuit generates a triac firing…
Free piston end position limiter
Granted: July 23, 1996
Patent Number:
5537820
A piston end position limiter for a free piston machine of the type having a piston sealingly reciprocating in a cylinder and separating a work space bounded at one end of the piston from a second space bounded at the opposite end of the piston. The work space and the second space contain a working fluid having an average pressure. A first valve is connected in communication between a fluid reservoir and the work space and is adapted to open only when the working fluid pressure varies…
Fluid bearing with compliant linkage for centering reciprocating bodies
Granted: June 11, 1996
Patent Number:
5525845
An improved mechanical transducer of the type having a body reciprocating in a chamber, the body being linked to a housing by a linkage including an axially compliant spring. An anti-friction fluid bearing applies a lateral centering force upon the body and a linkage component of the linkage has a lateral compliance sufficient for the centering forces exerted by the fluid bearing to at least equal the sum of lateral force exerted by the linkage and other lateral forces exerted upon the…
Free piston stirling machine having a controllably switchable work transmitting linkage between displacer and piston
Granted: April 2, 1996
Patent Number:
5502968
Free piston Stirling coolers and engines are improved by a variable power transmitting linkage connecting the displacer to the piston and coupling more power from the displacer to the piston while piston displacement exceeds a selected limit than coupled while piston displacement is less than the selected limit. Adjustment of the position of the limit is used to control stroke amplitude, power output or thermal pumping rate.
Method and apparatus for measuring piston position in a free piston compressor
Granted: March 5, 1996
Patent Number:
5496153
A method of measuring the distance at closest approach between the piston of a free piston compressor and the cylinder head. The method derives measurements of both the alternating and average components of piston position from direct measurements of the voltage and current applied to the linear permanent magnet motor that drives the piston, and thus eliminates any requirement for an additional position sensor located within the compressor.
Centering system with one way valve for free piston machine
Granted: October 31, 1995
Patent Number:
5461859
A piston centering system for a free piston machine. The invention uses a centering passageway which is in communication between a work space and a second space which spaces are formed in a housing and are separated by a piston which reciprocates in a cylinder in the housing. The centering passageway has a valve, such as a spool valve formed in the piston and cylinder or a center post, the valve opening in response to the piston being near the center of the opposite limits of its…
Pulse width modulator
Granted: September 12, 1995
Patent Number:
5450521
An electrical circuit and method for generating a continuous train of width modulated pulses. A square wave is generated and a delay circuit provides a delayed analog of the square wave. A controllable duration one-shot multivibrator generates a modulating pulse having a duration proportional to the sum of the absolute value of the modulating signal and a constant offset. The constant offset is chosen so that, in the absence of a modulating signal, the offset provides the largest control…
Free piston stirling machine having variable spring between displacer and piston for power control and stroke limiting
Granted: January 31, 1995
Patent Number:
5385021
Free piston Stirling coolers and engines are improved by a spring coupling the displacer to the piston and having a variable spring constant. Controllable variation of its spring constant permits controllable variation of displacer stroke, engine power output and cooler thermal pumping rate and thus the invention is useful for stroke limiting and load matching.
Voltage controlled thyristor
Granted: November 29, 1994
Patent Number:
5369291
A voltage controlled thyristor includes an intrinsic layer of material between an anode and a cathode and a gate region between the intrinsic layer and the cathode comprising a lightly doped P type layer with more heavily doped P type regions extending through the lightly doped layer into the intrinsic layer. The more heavily doped P type regions are interspersed among shallower N doped regions of the cathode. In a preferred embodiment, interdigitated ohmic contacts are formed on one…
