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:
May. 21, 1996
Filed:
Mar. 17, 1994
Osamu Kuroda, Hitachi, JP;
Takahiro Tachi, Hitachi, JP;
Miho Saito, Hitachi, JP;
Toshio Ogawa, Takahagi, JP;
Noriko Watanabe, Mito, JP;
Akira Kato, Mito, JP;
Hiroshi Miyadera, Hitachi, JP;
Hitachi, Ltd., , JP;
Abstract
An apparatus is provided for purifying an exhaust gas discharged from an internal combustion engine, which comprises a first exhaust gas passage including a nitrogen oxide removing catalyst and a three way catalyst, a second exhaust gas passage including the three way catalyst, a gas flow regulator for selectively directing the exhaust gas to the first and second exhaust gas passages, and a control unit which directs the exhaust gas to the first exhaust gas passage (thereby passing exhaust gas first through the nitrogen oxide removing catalyst and thereafter through the three way catalyst) when the temperature of the nitrogen oxide removing catalyst is within a hydrocarbon adsorbing range of temperature thereof while the engine is warming up, and to the second exhaust gas passage (thereby passing the exhaust gas only through the three way catalyst) when the temperature of the nitrogen oxide removing catalyst exceeds the hydrocarbon adsorbing range of temperature thereof.