The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 31, 2012
Filed:
Sep. 02, 2004
Zhuang Tian, Auckland, NZ;
John H. Boyd, Jr., Holland, MI (US);
Zhuang Tian, Auckland, NZ;
John H. Boyd, Jr., Holland, MI (US);
Fisher & Paykel Appliances Limtied, Auckland, NZ;
Abstract
A free piston gas compressor has a cylinder, a piston, the piston reciprocable within the cylinder in alternating compression and expansion strokes. A reciprocating linear electric motor is drivably coupled to the piston. A controller is programmed to control or adjust power input to the linear motor on the basis of a relationship including at least one of the present compression stroke or expansion stroke durations, the relationship being indicative of the top dead center (TDC) position of the piston, including in the absence of any collision. In the preferred embodiment the controller obtains a measure reflecting the difference between the compression stroke duration and the expansion stroke duration and adjusts the power input in response to the obtained measure.