N O x sensor cross sensitivity model and simultaneous prediction of N O x and N H 3 slip from automotive catalytic converters under real driving conditions

This work presents the development of a model to capture the NO_x sensors cross sensitivity behavior based on N O x sensor cell temperature, as well as a model do predict the slip of the NO_x and NH₃ after the SCR catalyst, as a way to reduce the error in the exhaust emissions estimation needed for feedback SCR control strategies. The emissions prediction model is based on the different cross sensitivity behavior of two distinct NO_x sensors. The proposed models were tested and compared on a fully instrumented engine test bench when applied in a Worldwide harmonized Light vehicles Test Cycle (WLTC) and a full map cycle. As a result, the proposed model showed for NO_x sensors cross sensitivity estimation an overall improvement of 34.8% for sensor 1 and 31.0% for sensor 2, and in terms of emissions prediction an overall improvement of 36.3% for NO_x and 45.5% for NH₃ slip.