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. 31, 2012
Filed:
Apr. 08, 2008
Takahiko Fujiwara, Susono, JP;
Hiroaki Mizoguchi, Susono, JP;
Norihisa Nakagawa, Numazu, JP;
Taiga Hagimoto, Susono, JP;
Naoto Kato, Susono, JP;
Shuntaro Okazaki, Susono, JP;
Takahiko Fujiwara, Susono, JP;
Hiroaki Mizoguchi, Susono, JP;
Norihisa Nakagawa, Numazu, JP;
Taiga Hagimoto, Susono, JP;
Naoto Kato, Susono, JP;
Shuntaro Okazaki, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota, JP;
Abstract
The present invention relates to an air-fuel ratio control device for an internal combustion engine, and makes it possible to maintain high purification performance by suppressing a decrease in the oxygen occlusion capability of a catalyst. When an Osensor output oxs is greater than a reference value oxsref, which corresponds to a stoichiometric air-fuel ratio, and smaller than an upper threshold value oxsrefR, a sub-FB reflection coefficient is fixed at a predetermined value vdoxfor providing a lean air-fuel ratio. When, on the other hand, the Osensor output oxs is smaller than the reference value oxsref and greater than a lower threshold value oxsrefL, the sub-FB reflection coefficient is fixed at a predetermined value vdoxfor providing a rich air-fuel ratio. The sub-FB reflection coefficient reflects the Osensor output oxs in the calculation of a fuel injection amount and increases or decreases to have a consequence on the air-fuel ratio of an exhaust gas.