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:
Nov. 04, 1997
Filed:
Aug. 30, 1996
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An air-fuel ratio control system for an internal combustion engine has an air-fuel ratio sensor arranged in the exhaust system of the engine, for detecting the air-fuel ratio of exhaust gases emitted from the engine, and various engine operating parameter sensors for detecting operating conditions of the engine. An ECU controls the air-fuel ratio of an air-fuel mixture to be supplied to the engine to a desired air-fuel ratio in a feedback manner responsive to an output from the air-fuel ratio sensor. A first learned value for correcting the desired air-fuel ratio is calculated based on the feedback control when the engine is detected to be in a first predetermined operating condition, and a second learned value for correcting the desired air-fuel ratio when the engine is detected to be in a second predetermined engine operating condition. The air-fuel ratio of the air-fuel mixture is controlled to a value leaner than a stoichiometric value, by using the first learned value. The first learned value is learned again when the difference between the first and the second learned values is larger than a predetermined re-learning-determining threshold value.