US 6,981,368 B2 | ||
Exhaust gas aftertreatment systems | ||
Michiel J. van Nieuwstadt, Ann Arbor, Mich. (US); and Devesh Upadhyay, Dearborn, Mich. (US) | ||
Assigned to Ford Global Technologies, LLC, Dearborn, Mich. (US) | ||
Filed on Nov. 21, 2002, as Appl. No. 10/301,387. | ||
Prior Publication US 2004/0098968 A1, May 27, 2004 | ||
Int. Cl. F01N 3/00 (2006.01) |
U.S. Cl. 60—277 | 18 Claims |
1. A method for diagnosing an exhaust gas aftertreatment device coupled downstream of an internal combustion engine, comprising:
calculating a difference between a measured and an estimated amount of an exhaust gas component downstream of the device;
and
providing an indication of device degradation based on a length of time a magnitude of said difference remains greater than
a predetermined constant.
|