Applying Matlab/Simulink to Study Calculation of NOx Efficiency of the SCR

An SCR system offers the opportunity for a car to get its nitrogen oxides inside the exhaust gas decreased. This can be achieved by dosing a reducing agent into the system which selectively reacts with the oxygen of the nitrogen oxides and therefore causes these emissions to be diminished. Depending on the operating point of an engine more or less NOx emissions can be reduced. Adaptation logic has the ability to find the optimum operating point at the NH3 slip limit. The adaptation logic requires the NOx emissions downstream from the SCR which will be measured by a NOx-Sensor. The goal of the module SCRChk_NOxEffCalc is the monitoring of NOx conversion efficiency of an SCR system. The monitoring function is based on a NOx sensor downstream from the SCR and the known NOx emissions upstream from the SCR.