US 12,291,984 B2
Method for evaluating an exhaust NOx sensor in the exhaust system of spark ignition internal combustion engine
Marc-Andre Golkowski, Hannover (DE); and Till Stoetzel, Velten (DE)
Assigned to Volkswagen Aktiengesellschaft, Wolfsburg (DE)
Filed by Volkswagen Aktiengesellschaft, Wolfsburg (DE)
Filed on Mar. 24, 2024, as Appl. No. 18/614,730.
Claims priority of application No. 10 2023 202 667.8 (DE), filed on Mar. 23, 2023.
Prior Publication US 2024/0318586 A1, Sep. 26, 2024
Int. Cl. F01N 11/00 (2006.01); F01N 3/10 (2006.01); F01N 13/00 (2010.01); F02D 41/14 (2006.01)
CPC F01N 11/007 (2013.01) [F01N 3/101 (2013.01); F01N 13/008 (2013.01); F01N 2550/02 (2013.01); F01N 2560/025 (2013.01); F01N 2560/026 (2013.01); F01N 2570/14 (2013.01); F01N 2570/18 (2013.01); F01N 2900/0404 (2013.01); F02D 2041/1417 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for evaluating a sensor signal of an exhaust NOx sensor that is disposed downstream of a three-way catalytic converter in an exhaust system of a spark ignition internal combustion engine, the method comprising:
modeling an ammonia factor downstream of the three-way catalytic converter using an ammonia formation model, the ammonia factor determining a deflection of the sensor signal of the exhaust NOx sensor caused by ammonia;
modeling a nitrogen oxide emission in the exhaust system downstream of the three-way catalytic converter using a nitrogen oxide model;
separating the modeled ammonia factor and the modeled nitrogen oxide emission by a separation algorithm using the sensor signal of the exhaust NOx sensor;
providing quantitative information, via the separation algorithm, about tailpipe ammonia emissions and tailpipe nitrogen oxide emissions of the spark ignition internal combustion engine; and
adjusting control of the spark ignition internal combustion engine based on said tailpipe ammonia emissions,
wherein the ammonia formation model takes into account:
a catalytic converter temperature of the three-way catalytic converter;
a combustion air ratio in the exhaust system downstream of the three-way catalytic converter; or
an exhaust gas volume flow of the internal combustion engine.