Paper Title
Physics based Modeling of Selective Catalytic Reduction System and Corresponding Reduced Order Dynamics

This paper focuses on developing the physics based model of the SCR system. Through the use of first principles, governing equations of the SCR physics based model are achieved. The SCR system is modeled in a series of segments. The main reactions are ammonia adsorption, desorption, reduction and ammonia oxidation. The resulting non-linear partial differential equations are discretized and linearized to obtain a state space model. The model is extended to sufficiently large order to achieve accuracy. The developed model is analyzed and the system dynamics are studied, validated using simulation studies of a Urea-SCR system. In addition, reduced order dynamics of the SCR system are also analyzed in this paper. Keywords - Emission reduction in Diesel engines, After-treatment system, SCR, Selective catalytic reduction modelling, Physics based SCR model.