Control Strategy for the Removal of NOx from Diesel Engine Exhaust using Hydrocarbon Selective Catalytic Reduction 2008-01-2486

A unique catalyst developed using high-throughput discovery techniques in collaboration with BASF Corporation and Accelrys, Inc. was investigated at General Motors under simulated diesel engine exhaust feed conditions for the selective catalytic reduction of NO_x. A hydrocarbon mixture was used as the reductant to model the multi-component nature of diesel fuel and the catalyst was evaluated over a wide range of temperatures (150 - 550°C) relevant to light-duty diesel exhaust. This report investigates the effects of NO_x (as NO or NO₂), hydrocarbon concentration level (HC:NO_x ratio), oxygen concentration, NO concentration, catalyst space velocity, catalyst temperature, and the co-presence of hydrogen on steady-state NO_x reduction activity. Using these results, a control strategy was developed to maximize NO_x conversion over the wide-ranging exhaust conditions likely to be encountered in light-duty diesel applications.