Numerical Modeling of Automotive Exhaust Catalysts

With a view to application of model base development to exhaust catalyst design, a numerical model for catalytic reaction was formulated so as to be able to predict tailpipe emission during test mode running. In order to grasp the catalytic reaction characteristics, catalyst characteristics test using catalyst test pieces and synthetic gas was conducted and the basic reaction that takes place inside the exhaust catalyst was modeled by employing the 3 overall reaction models: Arrhenius model, competitive adsorption model, and adsorption model. By using the formulated numerical catalyst model, tailpipe emission estimation for a gasoline engine vehicle was carried out, and an estimated accuracy of within ±10% error range from the actual measurement was realized for all of CO, HC, and NO.