Prediction of the NOx Dynamic Emissions for a Heavy Duty Diesel Engine SCR Application

Nitrogen oxides (NO_x) reduction technique is one of the hot topics for Diesel engine developers. In the SCR system, the required urea dosing quantity is calculated from the diesel engine raw emissions, so the estimation of the engine raw emissions is very important,. Because of the complexity and the nonlinearity of the engine model, the estimation results are always not satisfied, especially when the engine is in transient state. In this paper a DCE (Dynamic Compensation based Estimation) method is proposed to predict the NO_x emissions of a diesel engine. The simulation results show that the DCE method has a large potential to improve the NO_x estimation accuracy in transient state.