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:
Jul. 21, 1998
Filed:
Jan. 24, 1996
Yukio Kinugasa, Susono, JP;
Kouhei Igarashi, Susono, JP;
Takaaki Itou, Misima, JP;
Toshifumi Takaoka, Susono, JP;
Michihiro Ohashi, Misima, JP;
Koji Yokota, Nagoya, JP;
Toyota Jidosha Kabushiki Kaisha, Aichi, JP;
Abstract
The method for purifying combustion exhaust gas according to the present invention utilizes a NH.sub.3 decomposing catalyst. The NH.sub.3 decomposing catalyst in the present invention is capable of converting substantially all of the NH.sub.3 in the combustion exhaust gas to N.sub.2 when the air-fuel ratio of the exhaust gas is lean and the temperature of the catalyst is within a predetermined optimum temperature range. Further, when the exhaust gas contains NO.sub.x in addition to NH.sub.3, the NH.sub.3 decomposing catalyst is capable of reducing the NO.sub.x in the optimum temperature range even though the air-fuel ratio of the exhaust gas is lean. In the present invention, the conditions of the exhaust gas containing NO.sub.x are adjusted before it is fed to the NH.sub.3 decomposing catalyst in such a manner that the temperature of the exhaust gas is within the optimum temperature range and the air-fuel ratio of the exhaust gas is lean. Further, NH.sub.3 is added to the exhaust gas before it is fed to the NH.sub.3 decomposing catalyst. Therefore, a lean air-fuel ratio exhaust gas, at a temperature within the optimum temperature range, which contains both the NO.sub.x and NH.sub.3 is fed to the NH.sub.3 decomposing catalyst, and the NO.sub.x, as well as the NH.sub.3, in the exhaust gas is completely resolved by the NH.sub.3 decomposing catalyst.