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:
Jul. 27, 2004
Filed:
Aug. 20, 2001
Applicant:
Inventors:
Assignee:
Nissan Motor Co., Ltd., Yokohama, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
F01N 3/00 ;
U.S. Cl.
CPC ...
F01N 3/00 ;
Abstract
A first catalyst which stores or releases oxygen according to an air-fuel ratio, and a second catalyst which traps or releases NOx according to the air-fuel ratio, are provided in an exhaust passage of an engine . A controller temporarily shifts the air-fuel ratio of the engine to rich when it is determined that the NOx trap catalyst second catalyst is released. At this time, the controller increases a reducing agent supply amount due to the rich shift to be larger, the larger the oxygen amount stored by the two catalysts . In this way, the air-fuel ratio in the second catalyst is maintained at a target stoichiometric or rich air-fuel ratio.