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:
Feb. 25, 2014
Filed:
Feb. 22, 2006
Nobuyuki Kitamura, Minamitsuru-gun, JP;
Nobuyuki Kitamura, Minamitsuru-gun, JP;
Toyota Jidosha Kabushiki Kaisha, Tokyo, JP;
Abstract
In a fuel cell system including a stack of polymer electrolyte fuel cells, the wet state of electrolyte membranes in the fuel cell stack is detected according to a variation in measurement value of an alternating current impedance (AC impedance) of the fuel cell stack. In an adequate level of water content of the electrolyte membranes, the measurement value of the AC impedance is substantially constant and has a very little variation. In an excess level of water content of the electrolyte membranes, the measurement value of the AC impedance has a significant variation. The AC impedance of the fuel cell stack is determinable by frequency analysis of high-frequency noise generated by an inverter included in the fuel cell system.