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:
Oct. 29, 2002
Filed:
Jul. 19, 2001
Winfried Dölling, Weissenbrunn, DE;
Lothar Hofmann, Altenkunstadt, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A method is provided for the catalytic conversion of nitrogen oxides contained in the exhaust gas of an internal combustion engine. A reducing agent is added in a controlled manner upstream of a denitrification catalyst, as seen in exhaust gas flow direction, and in dependence on a nitrogen oxide concentration. The reducing agent is added in a superstoichiometric amount in relation to the nitrogen oxide content if an operating parameter and/or a value derived from the operating parameter falls below or exceeds a threshold value. The addition of the reducing agent is then terminated or continued in a substoichiometric manner. The invention provides a measure for obtaining an extremely high average nitrogen oxide conversion, especially under varying operating conditions of the internal combustion engine.