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:
May. 09, 2000
Filed:
Jun. 17, 1998
Nobuhide Kato, Ama-gun, JP;
Yasuhiko Hamada, Nagoya, JP;
NGK Insulators, Ltd., , JP;
Abstract
A gas sensor comprises a main pumping cell for pumping-processing oxygen contained in a first chamber, a feedback control system for comparing a partial pressure of oxygen in the first chamber with a first reference value to control the main pumping cell so that the partial pressure of oxygen has a predetermined value at which NO is not decomposable, an auxiliary pumping cell for pumping-processing oxygen in the second chamber, and a measuring pumping cell for pumping-processing oxygen produced by decomposition of NOx. The gas sensor further comprises a correcting control system for correcting and controlling the feedback control system on the basis of a difference between a second reference value and a value of a pumping current flowing through the auxiliary pumping cell to give a constant oxygen concentration in the second chamber, and a self-diagnosis unit for comparing the value of the pumping current with a prescribed range and judging whether or not any trouble occurs, on the basis of an obtained result of comparison. Accordingly, it is possible to provide the gas sensor having a self-diagnosis function capable of quickly and reliably detecting whether or not any trouble occurs.