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. 23, 2002
Filed:
Jan. 25, 2000
Bernardino M. Penetrante, San Ramon, CA (US);
George E. Vogtlin, Fremont, CA (US);
Bernard T. Merritt, Livermore, CA (US);
Raymond M. Brusasco, Livermore, CA (US);
The Regents of the University of California, Oakland, CA (US);
Abstract
A two-stage method for NO reduction in an oxygen-rich engine exhaust comprises a plasma oxidative stage and a storage reduction stage. The first stage employs a non-thermal plasma treatment of NO gases in an oxygen-rich exhaust and is intended to convert NO to NO in the presence of O and hydrocarbons. The second stage employs a lean NO trap to convert such NO to environmentally benign gases that include N , CO , and H O. By preconverting NO to NO in the first stage with a plasma, the efficiency of the second stage for NO reduction is enhanced. For example, an internal combustion engine exhaust is connected by a pipe to a first chamber in which a non-thermal plasma converts NO to NO in the presence of O and hydrocarbons, such as propene. A flow of such hydrocarbons (C H ) is input from usually a second pipe into at least a portion of the first chamber. The NO from the plasma treatment proceeds to a storage reduction catalyst (lean NO trap) that converts NO to N , CO , and H O, and includes a nitrate-forming catalytic site. The hydrocarbons and NO are simultaneously reduced while passing through the lean-NO trap catalyst. The method allows for enhanced NO reduction in vehicular engine exhausts, particularly those having relatively high sulfur contents.