The behaviour of aged three-way catalytic converters in the different modes of legislated cycles

Automotive three-way catalytic converters are routinely applied today in th e elimination of carbon monoxide, urburned or partially burned hydrocarbons and nitrogen oxides from gasoline engine exhaust gas. Catalyst activity in this case is only indirectly assessed by means of the measurement of overa ll emissions during a legislated driving cycle. The specific structure of t he driving cycles embodied in a legislated emissions test procedure, signif icantly affects catalyst performance. In addition, catalyst behaviour is af fected by the levels of raw engine emissions and catalyst inlet temperature s. The latter are strongly influenced by exhaust system design. The above e xplain easily the difficulties arising when one wants to discriminate betwe en the behaviour of different catalysts in a specific test procedure. The a dvent of reliable mathematical models of three-way catalytic converter oper ation allows for a detailed analysis of catalyst performance over the full legislated cycle, which gives more insight into the catalytic activity itse lf. In this paper, a specific experimental and computational case study is employed to demonstrate the role of mathematical modelling in the detailed analysis of aged catalyst performance during the US and EU legislated test procedures. Copyright (C) 2000 John Wiley & Sons, Ltd.