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. 01, 2003
Filed:
Apr. 20, 2001
Kengo Kubo, Yokohama, JP;
Kimiyoshi Nishizawa, Yokohama, JP;
Nissan Motor Co., Ltd., Yokohama, JP;
Abstract
A first NOx-trapping catalyzer unit is disposed on an upstream part of an exhaust passage. A second NOx-trapping catalyzer unit is disposed on a downstream part of the exhaust passage. A structure is provided that causes the first NOx-trapping catalyzer unit to be exposed to a relatively high temperature environment and causes the second NOx-trapping catalyzer unit to be exposed to a relatively low temperature environment. Each of the first and second NOx-trapping catalyzer units traps NOx when the exhaust gas applied thereto shows a leaner air/fuel ratio and releases and reduces NOx when the exhaust gas applied thereto shows a stoichiometric or richer air/fuel ratio. The first NOx-trapping catalyzer unit shows the basicity that is higher than that of the second NOx-trapping catalyzer unit or the first NOx-trapping catalyzer shows the reducing ability that is lower than that of the second NOx-trapping catalyzer unit.