The Optimization of Light-duty Diesel Oxidation Catalysts for Preturbo, Closed-coupled and Underfloor Positions 2004-01-3021

Diesel engines are very popular in European passenger cars and their technology has been developed to have cleaner raw emissions and lower fuel consumption. Therefore the exhaust temperatures are extremely low in urban driving conditions. The current diesel European driving cycle (EDC) and diesel catalyst ageing in different positions (Preturbo, CC and UF) were simulated successfully according to diesel light-duty exhaust gas conditions with laboratory equipment. A small mixer type EcoXcell structure was used in Preturbo position with high Pt loading to enhance in particular CO and hydrocarbon oxidations. The small metal substrated pre and larger main catalyst with active, zeolite containing washcoat were developed to decrease emissions. Both experimental and calculation simulations gave a prediction for grams per kilometer emissions for a single or combined catalyst system. The reaction and ageing rate based design can be used to optimize the diesel aftertreatment system. Engine experiments with a full-size Preturbo catalyst combined with a larger catalyst proved the efficiency of the developed catalysts.