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. 06, 2010
Filed:
May. 18, 2007
Bruce J. Clingerman, Palmyra, NY (US);
John P. Salvador, Penfield, NY (US);
Ronald L. James, North Chili, NY (US);
Bruce J. Clingerman, Palmyra, NY (US);
John P. Salvador, Penfield, NY (US);
Ronald L. James, North Chili, NY (US);
GM Global Technology Operations, Inc., Detroit, MI (US);
Abstract
A method for controlling the pressure within a fuel cell stack to control the stack relative humidity. In one embodiment, a two-position valve receiving the cathode exhaust is switchable between a fully open and a fully closed position, where the valve is opened when the fuel cell system is operating at a low operation temperature and the valve is closed when the fuel cell system is operating at a high operation temperature. A fixed restriction valve is provided in parallel with the two-position valve so that when the two-position valve is fully closed, the proper amount of pressure is provided at the cathode output. In another embodiment, the two-position valve employs leak paths so that when the two-position valve is in the closed position, the cathode exhaust gas can still flow through.