Highest NOx Conversion in SCR Catalysts through Model Based Control

To face the challenges of future emission legislations, such as EURO VI, US Tier 4 or Japanese Post PNLTR. A model-based control concept for SCR systems is developed. The control algorithm is built in a modular way, which allows the application of the control algorithm on various aftertreatment system configurations. Core of the control concept is a one-dimensional control-oriented SCR catalyst model which is verified and calibrated using experimental data from engine test bed. Based on this control-oriented SCR model, a control of the estimated ammonia loading of the real catalyst is performed. An integrated calibration procedure for the entire control algorithm is also developed. Experimental results showing the advantages of the control concept and maximum achievable NOx reduction rates in WHTC are presented.