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:
Nov. 02, 1999
Filed:
Apr. 11, 1997
Yukio Kinugasa, Susono, JP;
Takaaki Itou, Mishima, JP;
Naoto Suzuki, Susono, JP;
Koichi Takeuchi, Susono, JP;
Hiroshi Tanaka, Susono, JP;
Naohide Fuwa, Susono, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi-Ken, JP;
Abstract
In an exhaust gas purification device, a No. 1 cylinder of the engine is operated at a rich air-fuel ratio and other cylinders (No. 2 to No. 4) are operated at a lean air-fuel ratio. The exhaust gases from the No. 1 and No. 2 cylinders are mixed with each other to form a rich air-fuel ratio exhaust gas mixture. Further, since the air-fuel ratio of the No. 2 cylinder is lean, the exhaust gas from the No. 2 cylinder contains a relatively large amount of NO.sub.x. This rich air-fuel ratio exhaust gas mixture which contains a relatively large amount of NO.sub.X is supplied to a three-way catalyst. At the three-way catalyst, part of the NO.sub.X in the exhaust gas mixture is converted to NH.sub.3. The exhaust gas mixture flowing out from the three-way catalyst and the lean exhaust gas from the No. 3 and No. 4 flow into a common exhaust gas passage where they mix with each other to form a lean exhaust gas containing NH.sub.3 from the three-way catalyst and NO.sub.X from the No. 3 and No. 4 cylinders. This lean exhaust gas flows into a denitrating catalyst disposed on the common exhaust gas passage in which NO.sub.X in the exhaust gas is reduced by the NH.sub.3.