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:
Dec. 07, 1999
Filed:
Jun. 13, 1997
Applicant:
Inventors:
Assignee:
N.E. Chemcat Corporation, Tokyo, JP;
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
B01D / ;
U.S. Cl.
CPC ...
4232135 ; 4232137 ; 4232391 ; 4232392 ;
Abstract
This method comprises bringing exhaust gas from an internal combustion engine, which is operated at a fuel-lean air/fuel ratio, in contact with an iridium-containing catalyst in a first zone and then in contact with a platinum-containing catalyst in a second zone situated downstream of the first zone. This method is effective for exhaust gas from lean burn engines over a wide temperature range of 200 to 500.degree. C., produces less N.sub.2 O in a low-temperature range of 200 to 300.degree. C., and can purify exhaust gas stably and effectively even at a high temperature of 700.degree. C. or over.