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US006933151B2
(12) United States Patent ao) Patent No.: us 6,933,151 B2
Bailey et al. (45) Date of Patent: *Aug. 23,2005
(21) Appl. No.: 10/960,817
(22) Filed: Oct. 7, 2004
(65) Prior Publication Data
US 2005/0084973 Al Apr. 21, 2005
Related U.S. Application Data
(63) Continuation of application No. 09/927,718, filed on Aug. 10, 2001, now Pat. No. 6,803,236.
(51) Int. CI.7 G01N 31/10; G01N 27/04;
F01N 3/00
(52) U.S. CI 436/37; 60/276; 422/83;
422/90; 422/94; 422/98; 436/116; 436/118; 436/119; 436/122; 436/127; 436/137; 436/149;
436/151
(58) Field of Search 436/37,116,118-119,
436/122,127,137, 149, 151; 60/274, 276;
422/83, 90, 94, 98
(56) References Cited
U.S. PATENT DOCUMENTS
5,077,970 A 1/1992 Hamburg
5,159,810 A 11/1992 Gratter et al.
FOREIGN PATENT DOCUMENTS
EP 0915244 A2 12/1999
WO 0000728 6/2000
* cited by examiner
Primary Examiner—Arlen Soderquist
(74) Attorney, Agent, or Firm—Jimmy L. Funke
(57) ABSTRACT
A diagnostic system for monitoring catalyst performance in an exhaust system comprises a plurality of treatment devices catalytically treating an exhaust gas stream, and a plurality of gas sensors for monitoring the catalyst performance of the treatment devices to determine when sulfur poisoning occurs. An on-board diagnostic system receives signals from the gas sensors, and, based upon response time differentials between sensors, determines whether the treatment devices are experiencing sulfur poisoning.
8 Claims, 4 Drawing Sheets
