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. 28, 1998
Filed:
Feb. 10, 1997
Ronald Neufert, Michelau, DE;
Wieland Mathes, Michelau, DE;
Dagmar Schobert-Schaefer, Munchen, DE;
Lothar Hofmann, Burgkunstadt, DE;
Siemens Aktiengesellschaft, Munich, DE;
Abstract
A method is provided in which the reducing agent, during the starting phase of the internal-combustion engine and during operation with decreasing and, if appropriate, virtually constant exhaust gas temperature, is fed superstoichiometrically in relation to the nitrogen oxide concentration, while taking into account the temperature-dependent storage capacity of a denitration catalytic converter for the reducing agent. The reducing agent is otherwise fed substoichiometrically. In this manner, the catalytic converter is kept at all times at a preferred charge level, so that on one hand it is possible to provide sufficient stored reducing agent for the catalytic conversion and on the other hand it is possible to still have a reducing agent buffer available which avoids slip of the reducing agent. The invention can be used in all internal-combustion engines operated with air excess, such as diesel engines and lean-burn engines.