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:
Feb. 21, 1995

Filed:

Nov. 15, 1993
Applicant:
Inventors:

Yukio Miyashita, Wako, JP;

Hiroshi Ohno, Wako, JP;

Shinichi Kubota, Wako, JP;

Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
G01N / ;
U.S. Cl.
CPC ...
204401 ; 204406 ; 204421 ; 204425 ; 204426 ;
Abstract

A system for determining an oxygen concentration sensor deterioration caused when foreign particles has clogged at a slit for introducing exhaust gas of an internal combustion engine to block the same. Since it is found by the inventors that sensor output fluctuates greatly between its maximum and minimum values in a TDC interval as the clogging increases, the deviation between the maximum and minimum is first calculated. The calculated deviation is then compared with a reference value and if it exceeds the reference value, the sensor is presumed to deteriorate. The reference value is varied on engine speed, engine load, or an air/fuel ratio of the engine.


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