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. 22, 2000

Filed:

Sep. 08, 1998
Applicant:
Inventors:

Hisashi Kadowaki, Chita-gun, JP;

Kenji Yamamoto, Anjo, JP;

Assignee:

Denso Corporation, Kariya, JP;

Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F02M / ;
U.S. Cl.
CPC ...
123674 ; 123690 ;
Abstract

When fuel supply system abnormality diagnosis conditions are satisfied, the abnormality of a fuel supply system is diagnosed by comparing an air/fuel ratio deviation index value with a lean/rich abnormality determination value by diagnosis means. At this time, a hot lean abnormality determination value KHL is set leaner than an ordinary lean abnormality determination value KLL, and a hot rich abnormality determination value KHH is set richer than an ordinary rich abnormality determination value KLH by abnormality determination value setting means when the engine compartment temperature is high. As a result, it is possible to diagnose whether or not the fuel supply system is abnormal (i.e., an abnormal deviation in the air/fuel ratio) while preventing the mistake even when the engine compartment temperature is high, so that the early discovery of the abnormality and the prevention of the mistaken diagnosis are made compatible.


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