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:
Mar. 27, 2012
Filed:
Oct. 31, 2007
Tomoko Morita, Saitama-ken, JP;
Norio Suzuki, Saitama-ken, JP;
Katsuji Wada, Saitama-ken, JP;
Honda Motor Co., Ltd., Tokyo, JP;
Abstract
An exhaust emission control device for an internal combustion engine, which is capable of supplying a just enough amount of reducing agent to the NOx catalyst even when a catalyst is provided on an upstream side of the NOx catalyst. A catalyst and a NOx catalyst are disposed at respective upstream and downstream locations in an exhaust system, for purifying NOx and for trapping NOx under an oxidizing atmosphere and reducing the NOx under a reducing atmosphere, respectively. An air-fuel sensor is disposed between the catalyst and the NOx catalyst. A reducing agent is supplied to an upstream side of the catalyst, to control exhaust gases such that the gases form the reducing atmosphere. To determine time of termination of NOx reduction control, an amount of reducing agent supplied to the NOx catalyst is calculated, and calculation of the amount of reducing agent is started when the air-fuel ratio has converged within a vicinity of a target air-fuel ratio.