A multiple model-based controller for NOx reduction in a selective catalytic reduction system

This paper deals with the design of a multiple model based controller for the nitrogen oxide emissions (NO_x), from vehicles using the selective catalyst as an aftertreatment system. The selective catalyst reduction (SCR) system is nonlinear, since the chemical reactions involved are highly depending on the operating points. Local linear models were used for identification. Local internal controllers are integrated into a global controller. A Bayesian approach is used to mix the local output of the controllers. A detailed simulator is used for the multiple model identification and testing the controller. For validation, experimental data based on a standard transient test developed for Euro VI testing are used in the simulator. Results obtained for this control approach are compared to one model controller.