US 12,286,920 B1
System and method for detecting a failed nitrogen oxide sensor
Drew D. Wackerlin, Chillicothe, IL (US); Keerthana Prasad, Peoria Heights, IL (US); and Scott A. Wallington, Hopewell, IL (US)
Assigned to Caterpillar Inc., Peoria, IL (US)
Filed by Caterpillar Inc., Peoria, IL (US)
Filed on Jul. 19, 2024, as Appl. No. 18/778,574.
Int. Cl. F01N 3/20 (2006.01); F01N 3/021 (2006.01)
CPC F01N 3/208 (2013.01) [F01N 3/2066 (2013.01); F01N 3/021 (2013.01); F01N 2250/02 (2013.01); F01N 2560/026 (2013.01); F01N 2570/14 (2013.01); F01N 2610/02 (2013.01); F01N 2610/102 (2013.01); F01N 2900/0412 (2013.01); F01N 2900/0416 (2013.01); F01N 2900/1402 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for detecting a failure state of a nitrogen oxide (NOx) sensor in an engine, the method comprising:
ceasing to inject ammonia from an ammonia source to a selective catalytic reduction (SCR) system;
depleting a remaining ammonia in the SCR system so as to increase a NOx gas output downstream of the SCR system,
sensing the increased NOx gas output via a NOx sensor positioned at an outlet of the SCR system;
transmitting one or more NOx gas output readings from the NOx sensor to an electronic control module of the engine;
comparing the one or more NOx gas output readings to an expected NOx gas output based on engine operating conditions via the electronic control module;
determining the NOx sensor is in the failure state when the one or more NOx gas output readings deviate from the expected NOx gas output by a predetermined threshold amount; and
optimizing engine operation when the NOx sensor is determined to be in the failure state.