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. 22, 1998
Filed:
Nov. 20, 1996
Mazda Motor Corporation, Hiroshima-ken, JP;
Abstract
A catalyst degradation determination apparatus having O.sub.2 sensors provided at the upstream and downstream of a catalyst, detects degradation of the catalyst by, during A/F ratio feed-back control since an engine has been started, comparing an integrated value of output values from the upstream O.sub.2 sensor with that of output values from the downstream O.sub.2 sensor. Upon starting integration of the output values from the respective O.sub.2 sensors, change of activated status of the catalyst is judged. If the status of the catalyst is approximately the same as a previous status, the integration is started with previous integrated values. On the other hand, if the status of the catalyst is different from the previous status, the previous integrated values are reset, and the integration of the output values from the respective O.sub.2 sensors is started from the beginning. This prevents erroneous catalyst degradation determination.