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:
Aug. 27, 2013
Filed:
Jul. 25, 2011
Kenya Maruyama, Nissin, JP;
Kenya Maruyama, Nissin, JP;
Toyota Jidosha Kabushiki Kaisha, Toyota-shi, JP;
Abstract
An air-fuel ratio diagnostic device for an internal combustion engine. The device includes an air-fuel ratio that detects oxygen concentration in the exhaust. A determination unit determines a variation in air-fuel ratio between engine cylinders based on a detection value of the air-fuel ratio sensor. A change amount in the detection value for a certain time when the detection value is changing from a lean side peak value toward a rich side peak value is defined as a rich change rate. A change amount in the detection for a certain time when the detection value is changing from a rich side peak value toward a lean side peak value is defined as a lean change rate. The determination unit determines a degree of variation between the cylinders based on the rich and lean change rates.