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. 14, 2009
Filed:
Jun. 28, 2007
Tatsunori Katoh, Aichi-gun, JP;
Tatsunori Katoh, Aichi-gun, JP;
Denso Corporation, Kariya, Aichi-Pref., JP;
Abstract
An air-fuel ratio of each cylinder is estimated on the basis of the detection value of an air-fuel ratio sensor disposed in an exhaust confluent portion. An air-fuel ratio correction quantity is computed on the basis of the estimated air-fuel ratio of each cylinder and the air-fuel ratio correction quantity is learned by smoothing processing. The air-fuel ratio is corrected on the basis of the cylinder air-fuel ratio correction quantity, whereby the air-fuel ratio is controlled for each cylinder so as to reduce a variation in the air-fuel ratio between the cylinders. When a state in which the correction quantity of any cylinder is outside a specified range continues for a while during a period in which the air-fuel ratio is controlled for each cylinder, the correction quantity is prohibited from being learned, whereby the cylinder air-fuel ratio correction quantity is prevented from being erroneously learned.