US 11,879,367 B2
NOx sensor diagnostics in heavy-duty motor vehicle engines
Cynthia Chaffin Webb, Sedro-Woolley, WA (US); Charles Wayne Reinhardt Swart, Bellingham, WA (US); Maarten Meijer, Anacortes, WA (US); and Varun Ramesh, Bellingham, WA (US)
Assigned to PACCAR Inc, Bellevue, WA (US)
Filed by PACCAR Inc, Bellevue, WA (US)
Filed on Aug. 25, 2020, as Appl. No. 17/002,570.
Claims priority of provisional application 63/057,113, filed on Jul. 27, 2020.
Claims priority of provisional application 63/056,131, filed on Jul. 24, 2020.
Claims priority of provisional application 63/054,468, filed on Jul. 21, 2020.
Prior Publication US 2022/0025802 A1, Jan. 27, 2022
Int. Cl. F01N 11/00 (2006.01); F01N 3/20 (2006.01); F02D 41/14 (2006.01); F02D 41/22 (2006.01)
CPC F01N 3/208 (2013.01) [F01N 11/00 (2013.01); F02D 41/1441 (2013.01); F02D 41/1463 (2013.01); F02D 41/222 (2013.01); F01N 2390/02 (2013.01); F01N 2550/05 (2013.01); F01N 2560/026 (2013.01); F01N 2560/14 (2013.01); F01N 2590/08 (2013.01); F01N 2610/02 (2013.01); F01N 2610/1453 (2013.01); F01N 2900/1402 (2013.01)] 15 Claims
OG exemplary drawing
 
1. A method, comprising:
operating a diesel engine of a heavy-duty truck such that the diesel engine generates an exhaust gas flow and the exhaust gas flow flows into an exhaust after-treatment system of the heavy-duty truck, the exhaust after-treatment system including a close-coupled selective catalytic reduction system and an underbody selective catalytic reduction system downstream of the close-coupled selective catalytic reduction system with respect to the exhaust gas flow;
controlling a first DEF injector upstream of the close-coupled selective catalytic reduction system to increase a first rate at which the DEF injector injects DEF into the exhaust gas flow;
measuring a first level of NOx gases with a first NOx sensor upstream of the close-coupled selective catalytic reduction system and a second level of NOx gases with a second NOx sensor downstream of the close-coupled selective catalytic reduction system as the first rate at which the first DEF injector injects DEF increases;
using the measurements to determine a level of error in measurements provided by the first NOx sensor;
adjusting a subsequent measurement provided by the first NOx sensor based on the determined level of error in measurements provided by the first NOx sensor; and
controlling the first DEF injector to inject DEF at a first adjusted rate based on the adjusted measurement provided by the first NOx sensor;
controlling a second DEF injector downstream of the close-coupled selective catalytic reduction system and upstream of the underbody selective catalytic reduction system to increase a second rate at which the second DEF injector injects DEF into the exhaust gas flow;
measuring a third level of NOx gases with the second NOx sensor downstream of the close-coupled selective catalytic reduction system and upstream of the underbody selective catalytic reduction system and a fourth level of NOx gases with a third NOx sensor downstream of the underbody selective catalytic reduction system as the second rate at which the second DEF injector injects DEF increases;
using the measurements of the third and fourth levels of NOx gases to determine a level of error in measurements provided by the second NOx sensor;
adjusting a subsequent measurement provided by the second NOx sensor based on the determined level of error in measurements provided by the second NOx sensor; and
controlling the second DEF injector to inject DEF at a second adjusted rate based on the adjusted measurement provided by the second NOx sensor.