Hybrid Nonlinear Model Predictive Control of LNT and Urealess SCR Aftertreatment System

In recent years, more stringent regulatory standards (EURO 6 emission standards) with a real driving test have been adopted for diesel vehicles. To meet the new regulations, a lean NOx trap (LNT) followed by a urealess selective catalytic reduction [passive SCR (pSCR)], i.e., LNT-pSCR, has been proposed as one of the promising aftertreatment systems for light-duty vehicles. In this brief, we propose hybrid nonlinear model predictive control (NMPC) that determines the optimal timing of rich mode operation for the LNT-pSCR system. First, a 1-D fundamental dynamic model of the LNT-pSCR is derived and parameters are estimated using chassis dynamometer test data. Second, a post-injection map, which describes the characteristics of the engine raw emission flowing into the LNT-pSCR system in the period affected by the rich mode, is constructed using the data. Third, the computational burden of …