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:
Jul. 13, 1993
Filed:
Oct. 18, 1990
Shinpei Nakaniwa, Gunma, JP;
Japan Electronic Control Systems Co., Ltd., Isezaki, JP;
Abstract
An air/fuel ratio feedback control system for an internal combustion engine sets an air/fuel ratio feedback correction coefficient on the basis of an air/fuel ratio for an air/fuel mixture introduced into a combustion chamber of the engine, to cause the air/fuel ratio to approach a set point thereof. The correction coefficient consists of a rich control proportional component P.sub.R, a lean control proportional component P.sub.L and an integral component I. When the air/fuel ratio set by the feedback control system deviates from an initial set point (the stoichiometric value) due to deterioration of an oxygen sensor for detecting the air/fuel ratio, the feedback control system compensates for the deviation to cause the air/fuel ratio to approach the initial set point, by varying a ratio of the rich control proportional component P.sub.R to the lean control proportional component P.sub.L in accordance with magnitudes of rich and lean detection levels, or by correcting a balance between the rich and lean control proportional components P.sub.R and P.sub.L on the basis of a relationship between signal level varying speeds of the proportional components P.sub.R and P.sub.L, a relationship between rich and lean control times, a relationship between rich and lean detection levels or the like.