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:
Jan. 27, 2015
Filed:
Jan. 06, 2011
Kenya Maruyama, Nissin, JP;
Takahiro Nishigaki, Nagoya, JP;
Toshitake Sasaki, Toyota, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota-shi, JP;
Abstract
When an engine is in a predetermined steady operating state, a gradient accumulation average value ΔAulsa corresponding to the amount of change in the air-fuel ratio AF, detected by an air-fuel ratio sensor, over the period of time from when an upper peak is reached, at which the direction of change in the air-fuel ratio AF is inverted to when a lower peak is reached, at which the subsequent inversion of the direction occurs, is calculated (Sto S) and, when the calculated gradient accumulation average value ΔAulsa is greater than a predetermined threshold value ΔArefthat is determined in advance as an upper limit (absolute value) of the range, in which it may be determined that the air-fuel ratio is even between the cylinders of the engine (Sto S), it is determined that the engine is in an air-fuel ratio imbalance state, in which there is an imbalance in air-fuel ratio between the cylinders of the engine.