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.

Date of Patent:
Sep. 02, 1997

Filed:

Apr. 21, 1995
Applicant:
Inventors:

Akira Katoh, Wako, JP;

Hiroshi Kitagawa, Wako, JP;

Jun Takahashi, Wako, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01N / ;
U.S. Cl.
CPC ...
60276 ; 60285 ;
Abstract

An air-fuel ratio control system for an internal combustion engine having a catalytic converter arranged in the exhaust system, has an upstream oxygen sensor and a downstream oxygen sensor arranged in the exhaust system at locations upstream and downstream of the catalytic converter, respectively. An ECU determines a feedback control constant, based on an output from the downstream oxygen sensor, and determines an air-fuel ratio control amount, based on the determined feedback control constant and an output from the upstream oxygen sensor. The ECU carries out feedback-control of the air-fuel ratio of a mixture supplied to the engine by means of the determined air-fuel ratio control amount. The updating rate of the feedback control constant is set based on the temperature of the catalyst of the catalytic converter.


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