METHOD FOR DETERMINING THE CONCENTRATION OF AT LEAST ONE REACTION PRODUCT AT THE OUTLET OF A CATALYST
The invention relates to a method for determining the concentration of at least one reaction product at the outlet of a catalyst (DOC), in particular of a diesel oxidation catalyst, in the exhaust tract (2) of an internal combustion engine (1). In order to detect the reactions in the catalyst (DOC) as precisely as possible in a simple way, the catalyst (DOC) is divided in the direction of flow into a plurality n of individual cells (6) and the concentration c NO2,k of NO2 at the outlet of each cell (6) is determined by means of a discrete NO2 model on the basis of the inlet-side concentration of NO2 and the reaction rate r NO,1 for NO in the catalyst (DOC) and the concentration C NO2,n of NO2 at the outlet of the last cell (6) is associated with the concentration c NO2 of NO2 at the outlet of the catalyst (DOC).