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:
Aug. 06, 2002

Filed:

Nov. 09, 2000
Applicant:
Inventors:

Yuji Yasui, Wako, JP;

Yoshikazu Oshima, Wako, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01N 3/00 ;
U.S. Cl.
CPC ...
F01N 3/00 ;
Abstract

The characteristics of an output of an exhaust gas sensor with respect to an air-fuel ratio of an engine are expressed according to a quadratic function, and the parameters of the quadratic function are sequentially identified according to a sequential identifying algorithm using data of the output of the exhaust gas sensor and data of an output of an air-fuel sensor which detects the air-fuel ratio of the engine. Deterioration evaluating parameters whose values change as the deterioration of a catalytic converter processes are sequentially determined from the identified values of the parameters of the quadratic function, and the deteriorated state of the catalytic converter is evaluated based on the determined deterioration evaluating parameters.


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