The future exhaust emission legislation limits and the procedures for running the test cycles will have an important influence on future range extender concepts. Due to the special steady state operation strategy of the range extender engines, it is possible to create a simple methodology for comparing engine test bench emissions with the emission limits of exhaust gas legislations. Therefore the energy demand of a predefined vehicle was simulated with PHEM, a longitudinal dynamic simulation tool. According to that, the influence of different exhaust gas after treatment systems and preheating options on the tolerated raw emission concentration will be analyzed. With this information, a few chosen range extender engine concepts will be compared concerning their suitability for future exhaust emission legislations. The selection of the range extender concepts was carried out with the methotology of a value benefit analysis. In this analysis CI engine concepts have been analyzed concerning HVH, costs, package, efficiency and emissions. The data have been taken from literatur or from own test bench results. The best evaluated concept was the uniflow scavenged two-stroke engine with port fuel injection system. This system offers the best compromise between the different evalution criteria.