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:
Jun. 30, 1998
Filed:
Jan. 16, 1997
Shigeaki Kakizaki, Yokohama, JP;
Kenichi Sato, Yokohama, JP;
Koji Ishihara, Yokosuka, JP;
Mikio Matsumoto, Yokohama, JP;
Nissan Motor Co., Ltd., Kanagawa, JP;
Abstract
Two catalytic converters are disposed in series midway in an engine exhaust passage, and a by-pass valve selectively introduces exhaust into the upstream converter and a by-pass passage which by-passes the converter. When the catalyst temperature of the upstream catalytic converter exceeds a threshold value A, exhaust is routed to the by-pass passage. The catalyst temperature in the state when exhaust is routed to the upstream catalytic converter under steady state engine running conditions is stored as a convergence temperature depending on the engine running conditions. When exhaust is routed to the by-pass passage, exhaust is re-introduced into the upstream converter only when both the catalyst temperature and the convergence temperature corresponding to the running conditions at that time are less than a threshold value B which is less than the threshold value A. In this way, hunting of the by-pass valve operation is prevented.