Patent ID: 8024921

Claim:
A method of operating an internal combustion engine having an exhaust gas section with at least one SCR catalytic converter whose NOx conversion efficiency is regulated with a reagent substance, the method comprising: calculating a first NOx current occurring downstream after the SCR catalytic converter; measuring a second NOx current occurring downstream after the SCR catalytic converter with a NOx sensor, wherein the NOx sensor has a lateral sensitivity to the reagent substance; determining a difference between the first NOx current and the second NOx current; generating a reagent substance signal that establishes a dosage of the reagent substance, wherein the reagent substance signal is a function of the difference between the first NOx current and the second NOx current; providing the established dosage of the reagent substance to the SCR catalytic converter: and performing a plausibility check wherein a correction signal, which influences the reagent substance signal, is generated upon deviation of a comparison of a reagent substance quantity metered in a predefined time period with a reagent quantity converted in the SCR catalytic converter and a NOx quantity.