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. 18, 1995
Filed:
Jun. 22, 1993
Tatsunori Kato, Nagoya, JP;
Katsuhiko Kodama, Toyota, JP;
Koji Okawa, Toyota, JP;
Mitsuru Takada, Aichi, JP;
Toyoda Jidosha Kabushiki Kaisha, Kariya, JP;
Nippondenso Co., Ltd., Toyota, JP;
Abstract
An air-fuel ratio control apparatus constructed, in an engine of a type storing evaporated fuel generated in a fuel tank in a canister and thereafter drawing off the evaporated fuel to an intake side of an engine through a bleedoff passage, so as to inhibit renewal of an air-fuel ratio learning value when the evaporated fuel concentration is at a predetermined value or higher in case of learning and renewal of an air-fuel ratio in order to make feedback control of the air-fuel ratio of an air-fuel mixture supplied to the engine. In an apparatus which adsorbs evaporated fuel generated in a fuel tank in a canister and purges the evaporated fuel adsorbed in the canister to an intake side of an internal combustion engine together with air through a purge valve, an air-fuel ratio learning value is renewed in accordance with a deviation between an air-fuel ratio feedback FAF value detected by an oxygen sensor and a FAFSM value obtained by smoothing the FAF value with a large smoothing constant. Further, renewal of the air-fuel ratio learning value is inhibited when the concentration of the evaporated fuel is high, and renewal of the air-fuel ratio learning value is executed even during purge execution by the purge valve when the concentration is low.