ECU Capable Grey-Box Model for SCR Reactor
Syed Wahiduzzaman, Gamma Technologies, Inc.
A systematic procedure for deriving reduced order models from detailed models of a SCR reactor is presented. The grey-box model derived using this procedure consists of non-stiff system of equations which can be solved with an explicit solver, has low memory footprint, two to three orders of magnitude faster than the detailed model, and has same level of accuracy as detailed model for wide range of the operating conditions studied. The proposed model remains fundamentals-based, with model parameters directly related to physical and chemical properties of the catalyst, and can be used on embedded and HiL systems to predict ammonia storage, NOx conversion efficiency and ammonia slip during the drive-cycle analysis. Next, based on this model, an observer based state-feedback controller is derived that demonstrates the potential performance improvement of the model based control design. Finally, the model code is embedded into an ECU to verify the real time capability of the proposed grey-box model.