Sunpower: U.S. Patents

The world leader in free-piston Stirling engines and coolers
and in linear compressors

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U.S. Patents

Patent Number	Title	Issue Date

7,453,241	Electronic Controller Matching Engine Power to Alternator Power and Maintaining Engine Frequency for a Free-Piston Stirling Engine Driving a Linear Alternator	18-Nov-08
7,437,878	Multi-Stage Pulse Tube Cryocooler with Acoustic Impedance Constructed to Reduce Transient Cool Down and Thermal Loss	21-Oct-08
7,434,409	Pulse Tube Cooler Having 1/4 Wavelength Resonator Tube Instead of Reservoir	14-Oct-08
7,409,833	Dual Mode Compressor With Automatic Compression Ration Adjustments For Adapting To Multiple Operating Conditions	12-Aug-08
7,372,255	Detection of the Instantaneous Position of a Linearly Reciprocating Member Using High Frequency Injection	13-May-08
7,266,947	Temperature Control For Free-Piston Cryocooler with Gas Bearings	11-Sept-07
7,210,312	Energy Efficient, Inexpensive Extraction of Oxygen from Ambient Air for Portable and Homse Use	1-May-07
7,043,835	Method for Centering Workpiece on the Cylindrical Axis of a Bore	16-May-06
7,000,390	Stirling Cycle Engine or Heat Pump With Improved Heat Exchanger	21-Feb-06
6,991,023	Involute Foil Regenerator	31-Jan-06
6,920,967	Controller for Reducing Excessive Amplitude of Oscillation of Free Piston	26-Jul-05
6,817,221	Wound Regenerator Method	16-Nov-04
6,782,700	Transient Temperature Control System & Method for Preventing Destructive Collisions in Free Piston Machines	31-Aug-04
6,684,637	Parallel Flow Slot Heat Exchanger	03-Feb-04
RE 38,337	Centering System for Free Piston Machine - REISSUE	02-Dec-03
6,536,326	Control System and Method for Preventing Destructive Collisions in Free Piston Machines	25-Mar-03
6,446,336	Heat Exchanger and Method of Constructing Same	10-Sep-02
6,293,184	Gas Bearing and Method of Making a Gas Bearing for a Free Piston Machine	25-Sep-01
6,199,381	DC Centering of Free Piston Machine	13-Mar-01
6,170,442	Free Piston Internal Combustion Engine	09-Jan-01
6,038,874	Refrigeration Circuit Having Series Evaporators and Modulatable Compressor	31-Mar-00
6,035,637	Free-Piston Internal Combustion Engine	14-Mar-00
5,941,079	Microminiature Stirling Cycle Cryocoolers and Engines	24-Aug-99
5,873,246	Centering System for Free Piston Machine	23-Jul-98
5,775,273	Free Piston Internal Combustion Engine	12-May-98
5,749,226	Microminiature Stirling Cycle Cryocoolers and Engines	12-May-98
5,715,693	Refrigeration Circuit Having Series Evaporators and Modulatable Compressor	10-Feb-98
5,642,622	Refrigerator with Interior Mounted Heat Pump	01-Jul-97
5,642,088	Magnet Support Sleeve for Linear Electromechanical Transducer	24-Jun-97
5,592,073	Triac Control Circuit	07-Jan-97
5,537,820	Free Piston End Position Limiter	23-Jul-96
5,525,845	Fluid Bearing With Compliant Linkage for Centering Reciprocating Bodies	11-Jun-96
5,502,968	Free Piston Stirling Machine Having a Controllably Switchable Work Transmitting Linkage Between Displacer and Piston	05-May-96
5,496,153	Method and Apparatus for Measuring Piston Position in a Free Piston Compressor	05-Mar-96
5,461,859	Centering System with One Way Valve for Free Piston Machine	31-Oct-95
5,457,956	Microminiature Stirling Cycle Cryocoolers and Engines	17-Oct-95
5,450,521	Pulse Width Modulator	12-Sep-95
5,385,021	Free Piston Stirling Machine Having Variable Spring Between Displacer and Piston for Power Control and Stroke Limiting	31-Jan-95
5,342,176	Method and Apparatus for Measuring Piston Position in a Free Piston Compressor	30-Aug-94
5,148,066	Linear Generator or Motor with Integral Magnetic Spring	15-Sep-92
5,003,777	Asymmetric Gas Spring	02-Apr-91
4,926,123	Precision Variable Pitch Compensation Winding for Displacement Transducer	27-Mar-90
4,912,409	Actuator Displacement Transducer Having External Flux Excluding Tube	27-May-90
4,866,378	Displacement Transducer with Opposed Coils for Improved Linearity and Temperature Compensation	05-Sep-89
4,864,232	Temperature Compensation for Displacement Transducer	09-May-89
4,805,408	Stirling Engine Power Regulation System	21-Feb-89

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