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:
Aug. 24, 2004
Filed:
May. 02, 2003
Christopher A. Laroo, Canton, MI (US);
Charles R. Schenk, Ypsilanti, MI (US);
Joseph F. McDonald, Ann Arbor, MI (US);
Byron J. Bunker, Ann Arbor, MI (US);
Brian A. Olson, Jackson, MI (US);
Robert E. Moss, Belleville, MI (US);
Daniel C. Stokes, Ann Arbor, MI (US);
Paul Anthony Way, Canton, MI (US);
The United States of America as represented by the Environmental Protection Agency, Washington, DC (US);
Abstract
The method of treating a fuel lean exhaust containing NO and SO includes splitting the exhaust into major and minor portions for flow through multiple flow paths each of which contains a particulate trap and an absorber containing a NO oxidation catalyst and a nitrate absorbent. The major portion is passed through a flow path in the lean state at a first temperature to convert the NO to nitrate and the SO to sulfate. After the first period of operation flows are switched so that one flow path receives a minor exhaust portion for a second period of time during which fuel is injected into that flow path along with diversion of a portion of exhaust from another flow path through a bypass. When during the second period of operation the particulate trap reaches a predetermined temperature, the flow path is opened to an increased exhaust flow to transfer heat from the particulate trap to the NO absorber to bring the NO absorber to a temperature suitable for sulfation, at which time fuel and a small portion of exhaust gas are again introduced in order to effect the desulfation.