Method and control assembly for operating an exhaust gas system

摘要

A method for operating an exhaust gas system of a vehicle in which an amount of a reducing agent (e.g. urea) to be supplied to the exhaust gas of an engine is determined. Measurements are evaluated which indicate a content of nitrogen oxides (NOx) in the exhaust gas downstream of a catalytic device 12 (e.g. SCR) adapted to diminish the content of nitrogen oxides in the exhaust gas. A magnitude and a frequency of the measurements are taken into account in determining the amount of the reducing agent to be supplied to the exhaust gas. A plurality of measurements is captured during a predetermined period of time. A magnitude of a measurement captured within this period of time is related to a quantity which is derived (averaged) from the respective magnitudes of the plurality of measurements. The related measurement is then utilized to determine the amount of the reducing agent to be supplied to the exhaust gas.