Internal combustion engines were the technology of choice for propulsion and decentral power supply in the last century. Due to the high energy density of hydrocarbon based fuels that could so far not be reached by alternative technologies they will keep their leading role in most applications for the next decades. Although, its general functionality seems to be unchanged since its invention, the internal combustion engine has gone through substantial developments driven by various challenges. Within these, the pollution control has to be named first due to its role as the main driver for engine and aftertreatment development since the discussions on air quality which started 70 years ago. Meanwhile, all industrialized countries and most of the emerging countries have more or less stringent regulations for the main harmful exhaust components (HC, CO, NOX, Particulates). The second main challenge to be named is the reduction of CO2 emissions. Various engine technologies that are currently used to tackle these global trends lead to major impact on the exhaust aftertreatment components. To tackle these challenges the exhaust aftertreatment development has to be understood as integrated, multi-disciplinary and multi-scale design process considering engine design and operation, on board diagnosis and aftertreatment design and operation likewise.