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:
Aug. 10, 1993
Filed:
Jul. 23, 1992
Kazunari Komatsu, Hiroshima, JP;
Mazda Motor Corporation, Hiroshima, JP;
Abstract
In an exhaust system for an internal combustion engine, including an upstream catalytic converter and a downstream catalytic converter, emission levels of exhaust gas are detected at positions upstream from the upstream catalytic converter, between the upstream and downstream catalytic converters, and downstream from the downstream catalytic converter, respectively. An air-fuel ratio is feedback controlled based on an emission level detected by the first emission sensor or feedback controlled based on an emission level detected by the second emission sensor when the engine operates in a specific vehicle operating condition. Deterioration of the downstream catalytic converter is detected based on an emission level detected by the third emission sensor while an air-fuel ratio is feedback controlled based on the emission level detected by the second emission sensor.