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. 16, 1994
Filed:
Mar. 16, 1993
Applicant:
Inventor:
Kazunari Komatsu, Hiroshima, JP;
Assignee:
Mazda Motor Corporation, Hiroshima, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01N / ;
U.S. Cl.
CPC ...
60276 ; 60277 ; 123688 ; 123691 ;
Abstract
An engine exhaust purification system is provided with a catalyst in an exhaust line, and oxygen sensors disposed in the exhaust line upstream and downstream from the catalyst, respectively. Deterioration of the catalyst is judged based on a frequency ratio of reversal of an output from the downstream oxygen sensor with respect to a threshold value to an output from the upstream oxygen sensor with respect to a threshold value. The threshold value of the deteriorated oxygen sensor is changed so as to vary the frequency ratio of reversal.