Prediction of Catalytic Performance during Light-off Phase with Different Wall Thickness, Cell Density and Cell Shape 2001-01-0930

Further stringent emission legislation requires advanced technologies, such as sophisticated engine management and advanced catalyst and substrate to achieve high catalytic performance, especially during the light-off phase. This paper presents the results of calculations and measurements of hydrocarbon and carbon monoxide light-off performance for substrates of different wall thickness, cell density and cell shapes.

The experimental data from catalyst light-off testing on an engine dynamometer are compared with theoretical results of computer modeling under different temperature ramps and flow rates. The reaction kinetics in the computer modeling are derived from the best fit for the performance of conventional ceramic substrate (6mil/400cpsi), by comparing the theoretical and experimental results on both HC and CO emissions. The calibrated computer model predicts the effects of different wall thickness, cell density and cell shape. Different cell shapes, Triangle, Square, and Hexagon, are chosen as typical cell shapes used in the market. The substrates that are tested have the same Geometric Surface Area (GSA) on the basis of bare substrate, providing a fair basis of comparison. Furthermore, the influence of material properties on light-off performance is studied.