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:
Dec. 03, 1991
Filed:
Sep. 07, 1990
Applicant:
Inventor:
Nobuaki Kayanuma, Gotenba, JP;
Assignee:
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01N / ;
U.S. Cl.
CPC ...
60274 ; 60276 ; 60277 ;
Abstract
In a double air-fuel ratio sensor system having two air-fuel ratio sensors upstream and downstream of a catalyst converter, a main air-fuel ratio correction amount is calculated in accordance with the output of the upstream air-fuel ratio sensor, and a sub air-fuel ratio correction amount is calculated in accordance with the output of the downstream air-fuel ratio sensor, thereby adjusting an air-fuel ratio using the two air-fuel ratio correction amounts. When the sub air-fuel ratio correction reaches a lean limit value, an ignition system is determined to be abnormal and a misfire may occur.