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:
Apr. 05, 1994
Filed:
Apr. 27, 1993
Tatsunori Kato, Nagoya, JP;
Katsuhiko Kodama, Toyota, JP;
Masahiko Tajima, Takahama, JP;
Junya Morikawa, Kasugai, JP;
Nippondenso, Co., Ltd., Kariya, JP;
Abstract
An air-fuel ratio control apparatus for an internal combustion engine for learning and controlling an air-fuel ratio accurately even during execution of purging of evaporated fuel. The evaporated fuel generated in a fuel tank is adsorbed to a canister, and the adsorbed fuel is evaporated and purged together with air to the intake side of the internal combustion engine through a purge valve. During normal purge rate control by the purge valve, air-fuel ratio feedback values detected by an oxygen sensor are averaged, and the concentration of the evaporated fuel taken into the internal combustion engine through the purge valve is detected by the deviation from a stoichiometric air-fuel ratio 1 of the averaged value and the purge rate. Further, after the lapse of a predetermined period of time after purging is started, air-fuel ratio learning values are renewed in accordance with the air-fuel ratio feedback value and stored in a RAM.