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:
Feb. 24, 2015
Filed:
Aug. 06, 2009
Yasushi Iwazaki, Ebina, JP;
Hiroshi Miyamoto, Susono, JP;
Fumihiko Nakamura, Susono, JP;
Hiroshi Sawada, Gotenba, JP;
Toru Kidokoro, Hadano, JP;
Yasushi Iwazaki, Ebina, JP;
Hiroshi Miyamoto, Susono, JP;
Fumihiko Nakamura, Susono, JP;
Hiroshi Sawada, Gotenba, JP;
Toru Kidokoro, Hadano, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota-shi, JP;
Abstract
An air-fuel ratio imbalance among cylinders determining apparatus according to the present invention obtains an output Vabyfs of an air-fuel ratio sensor disposed at a portion downstream of an exhaust gas aggregated portion of an exhaust gas passage, and obtains a second-order differential value d2AF (a change rate of a change rate of a detected air-fuel ratio abyfs) of a detected air-fuel ratio abyfs represented by the air-fuel ratio sensor output Vabyfs. The imbalance determining apparatus determines that an air-fuel ratio imbalance state among cylinders is occurring when a detected air-fuel ratio second-order differential corresponding value (for example, a second-order differential value d2AF per se) obtained in accordance with the second-order differential value d2AF is larger than a first threshold value.