Exhaust-gas after treatment system i.e. nitrogen oxide contained internal combustion engine, monitoring method, involves detecting error of reducing agent in case of deviation of measured nitrogen oxide conversion of stored value

摘要

The method involves determining a value for an actual filling condition of a reducing agent in a reducing agent tank as a characteristic value and storing the value in a non volatile memory of a controller. The stored value at the beginning of a new operating cycle is compared with a current value for the filling level in the tank. Nitrogen oxide (NOx) conversion to a defined operating time point is determined if a refilling procedure at the reducing agent is determined. An error of the reducing agent is detected in case of deviation of the measured NOx conversion of the stored value.