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:
Sep. 16, 2003
Filed:
Oct. 16, 2001
Nissan Motor Co., Ltd., Yokohama, JP;
Abstract
A microprocessor ( ) computes an oxygen storage amount of a catalyst ( ) separately for a high speed component and a low speed component in accordance with real characteristic. A target air-fuel ratio of an engine ( ) is computed and air-fuel ratio control of the engine ( ) it is performed so that the high speed component is constant. The deterioration of the catalyst ( ) is determined by integrating the high speed component of the oxygen storage amount computed during the air-fuel ratio control process for a predetermined number of times, and comparing its average value with a determining value. The oxygen storage amount of the high speed component which is sensitive to catalyst deterioration is integrated so as to obtain a highly precise determining result to determine the deterioration.