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. 09, 2000
Filed:
May. 22, 1998
Tetsuya Yamashita, Susono, JP;
Toshiaki Tanaka, Numazu, JP;
Shinichi Takeshima, Susono, JP;
Shinya Hirota, Susono, JP;
Eiji Iwasaki, Susono, JP;
Kouji Yoshizaki, Numazu, JP;
Nobumoto Ohashi, Susono, JP;
Kazuhiro Itoh, Mishima, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
A device for purifying the exhaust gas of an engine comprises a NO.sub.X absorbent arranged in the exhaust passage. The NO.sub.X absorbent absorbs NO.sub.X therein when the air-fuel ratio of the inflowing exhaust gas is lean, and releases the absorbed NO.sub.X therefrom when the oxygen concentration in the inflowing exhaust gas becomes lower. The NO.sub.X absorbent also absorbs SO.sub.X therein when the air-fuel ratio of the inflowing exhaust gas is lean, and releases the absorbed SO.sub.X therefrom when the oxygen concentration in the inflowing exhaust gas becomes lower, with the temperature of the NO.sub.X absorbent being higher than a SO.sub.X releasing temperature. The air-fuel ratio of the exhaust gas flowing to the NO.sub.X absorbent is made rich temporarily when the temperature of the NO.sub.X absorbent is higher than SO.sub.X releasing temperature and when the flow rate of the exhaust gas flowing through the NO.sub.X absorbent is lower than a predetermined flow rate, to release the absorbed SO.sub.X from the NO.sub.X absorbent.