Measurement and control method and apparatus for an SCR exhaust aftertreatment system with determination of the linear relationship between two signals determined by means of NOx sensors

摘要

Measuring method for an SCR exhaust aftertreatment system (5) of a vehicle, wherein the SCR exhaust aftertreatment system - an SCR catalyst (4), - a urea introduction device (3), - a first NOx sensor (1), the exhaust gas upstream of the SCR- Catalyst (4) and the urea introduction device (3) is arranged, and - a second NOx sensor (2), which in the SCR catalyst (4) or downstream of the exhaust gas downstream of the SCR catalyst (4) is arranged, comprising the steps: - determining a first signal (18) by means of the first NOx sensor (1); - determining a second signal (12) by means of the second NOx sensor (2); and - determining a linearity indication (23, 24) based on the first signal (18) and the second signal (12), which is a measure of the linear relationship between the two signals, wherein as a linearity indication (23, 24) a correlation coefficient of the two Signals is determined.