Simulation of a catalytic converter of automotive exhaust gas under dynamic conditions

An adiabatic, one-dimensional model of a catalytic converter of automotive exhaust gas was used to simulate the behaviour during cyclic feeding and warming-up. Both the oxidation of CO, C2H2 and C2H4, and the reduction of NO are considered. Accumulation of mass in the bulk gas phase, in the pores of the washcoat and on the catalyst surface is accounted for, as is accumulation of energy in both the gas and the solid phase. Exhaust gas components are converted in a fixed sequence and the Light-off temperature of individual components is rather irrelevant for the behaviour of a real exhaust gas because of mutual interactions in a mixture. Forced concentration cycling below the Light-off temperature of CO, C2H2 and C2H4 can reduce the emissions of the individual components, but the optimal feed temperature is not the same for each component.