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:
Aug. 05, 2003
Filed:
Jan. 15, 2002
Applicant:
Inventors:
Assignee:
Denso Corporation, Kariya, JP;
Attorney:
Primary Examiner:
Assistant Examiner:
Int. Cl.
CPC ...
F01N 3/00 ;
U.S. Cl.
CPC ...
F01N 3/00 ;
Abstract
An emission control apparatus for an engine has a plurality of catalysts disposed in series in an exhaust passage. An HC absorbent catalyst is utilized for at least one of the catalysts. An ECU controls an A/F ratio in an upstream side of the HC absorbent catalyst at a target value. The target value is corrected to a leaner value when the HC absorbent catalyst is in a desorbing condition. The leaner value is leaner than the target value during the HC absorbent catalyst is in an absorbing condition or an activated condition. The leaner atmosphere provides sufficient of oxygen to purify desorbed HC from the HC absorbent catalyst itself.