Future, upgraded exhaust aftertreatment systems for Automotive Diesel engines for proper compliance with new regulations

Modern Diesel engine technology represents an attractive platform for compliance with both, lowered CO2 emissions through highly efficient combustion as well as for substantially strengthened emission norms worldwide. The upcoming new emission test procedures in the EU like WLTC/RDE and PEMS conclude in extended emission relevant engine operation areas. Besides the increased coverage of engine load also the emission testing from cold start to high temperature cycles demand an extended active temperature range of aftertreatment systems. Additionally, improved combustion with increased fuel efficiency and thereby lowered exhaust gas temperature define even more challenging boundaries for exhaust aftertreatment functionalities. With respect to the increased scope of demands specifications of aftertreatment systems have to be upgraded and alternative solutions and technologies are moving forward in development and technical realization.
Meeting all sometimes contradictory requirements, advanced combined aftertreatment systems allow the best overall performance by the benefit of synergistic effects. Besides the proven DPF-based soot reduction technology, the combination of LNT and SCR functionalities seems promising as one technology module for NOx treatment in passenger car applications. This paper focusses on various passive and active LNT and SCR combination variants and comprehensively investigates the overall DeNOx performance.