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:
Dec. 28, 2004
Filed:
Apr. 10, 2001
Akira Hashimoto, Wako, JP;
Kotaro Miyashita, Wako, JP;
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An exhaust emission control system for an internal combustion engine having nitrogen oxides removing device provided in an exhaust system of the engine for removing nitrogen oxides in exhaust gases and an oxygen concentration sensor provided downstream of the nitrogen oxides removing device for detecting the concentration of oxygen in the exhaust gases. Deterioration of the nitrogen oxides removing device is determined on the basis of an output of the oxygen concentration sensor after the air-fuel ratio has been changed from the lean region to a rich region with respect to the stoichiometric ratio. Abnormality of the oxygen concentration sensor is determined on the basis of an output of the oxygen concentration sensor during a period in which the air-fuel ratio is kept in the rich region with respect to the stoichiometric ratio immediately after execution of the deterioration determination of the nitrogen oxides removing device.