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. 02, 2002
Filed:
Aug. 31, 1999
Karl C. C. Kharas, Tulsa, OK (US);
Heinz J. Robota, Tulsa, OK (US);
Delphi Technologies, Inc., Troy, MI (US);
Abstract
A process for removal of carbon monoxide, hydrocarbons, and nitrogen oxides from the exhaust gas from lean-burn, diesel and other engines which produce exhaust gases containing excess oxygen is disclosed. An exhaust gas from an engine operating at an air-fuel ratio above about 18 is contacted with a multi-component catalyst having at least two catalytic components, each capable of reducing nitrogen oxides within a range of exhaust gas temperatures that is different from the range of exhaust gas temperatures within which each other component is capable of reducing nitrogen oxides. Oxidation of the remaining reducing gases is also accomplished. One example of a two catalytic component catalyst of this invention has a first component of Au supported on alumina, which reduces nitrogen oxides at exhaust gas temperatures between about 600° C. and 900° C., and a second component of Pt supported on Y-zeolite, which reduces nitrogen oxides at exhaust gas temperatures below 600° C.; an example of a three catalytic component catalyst of this invention has a first component of CoO supported on &ggr;-alumina, which reduces nitrogen oxides at exhaust gas temperatures above about 475° C., a second component of an alloy of Pt, Rh and Co supported on BaO -stabilized &dgr;-alumina, which reduces nitrogen oxides at exhaust gas temperatures between about 315° C. and about 475° C. and a third component of an alloy of Pt and Rh supported on &ggr;-alumina, which reduces nitrogen oxides at exhaust gas temperatures between about 200° C. and about 425° C.