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:
Sep. 21, 1999
Filed:
Aug. 07, 1997
Honda Giken Kogyo Kabushiki Kaisha, Tokyo, JP;
Abstract
An air-fuel ratio control system for an internal combustion engine includes an air-fuel ratio sensor arranged in an exhaust system thereof for generating an output substantially proportional in value to an air-fuel ratio of exhaust gases emitted from the engine. An amount of variation in combustion of the engine is detected. A desired air-fuel ratio of a mixture supplied to the engine is set to a value leaner than a stoichiometric air-fuel ratio based on the amount of variation in combustion of the engine, when the engine is in a predetermined operating condition. Feedback control of an air-fuel ratio of the mixture to the desired air-fuel ratio is carried out in response to the output from the air-fuel ratio sensor. The desired air-fuel ratio is set to a richer value than an immediately preceding value thereof when the amount of variation in combustion of the engine detected is large and to a leaner value than the immediately preceding value thereof when the amount of variation in combustion of the engine is small. A value of the desired air-fuel ratio set is learned as an actual lean limit of the air-fuel ratio for stable combustion of the engine. A rate of change of the desired air-fuel ratio is adjusted based on the learned value of the desired air-fuel ratio.