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The future of the combustion engine will to some extent depend on the use of CO2-neutral eFuels to avoid further fossil CO2 emissions. Also, the use of synthetic fuels offers the possibility to improve various engine properties, such as thermodynamics, EGR compatibility or emissions, through targeted influence on specific fuel properties. To this end, a methodology was generated to attribute various engine effects to particular fuel properties. Therefore, the Chair of Combustion Engines (LVAS) at the TU Dresden developed a fully automated testbed for motorcycle engines, including clutch and gear switching mechanisms. Hitherto, emissions measurements for motorcycles were done mostly on chassis dynamometers, with the disadvantage of a large spread of results. Due to the lack of consistency the analysis of fuel properties was not possible. To prove the developed methodology, a test campaign including 15 different gasoline fuels was elaborated in cooperation with KTM R&D GmbH.

Hybridization is a promising way to further reduce the CO2 emissions of passenger vehicles. However, high engine efficiencies and the reduction of engine load, due to torque assists by an electric motor, cause a decrease of exhaust gas temperature levels. This leads to an increased time to catalyst light-off, resulting in an overall lower efficiency of the exhaust aftertreatment system (ATS). Especially in low load driving conditions, at cold ambient temperatures and on short distance drives, the tailpipe pollutant emissions are severely impacted by these low ATS efficiency levels. To ensure lowest emissions under all driving conditions, catalyst heating methods must be used. In conventional vehicles, internal combustion engine measures (e.g. usage of a dedicated combustion mode for late combustion) can be applied. A hybrid system with an electrically heated catalyst (EHC) enables further methods such as the increase of engine load by the electric motor or electric catalyst heating.

Modern vehicles need to fulfil challenging requirements with respect to emissions, noise and fuel consumption. Up to the EU5 legislation a sound steady state application was sufficient for passenger car Diesel engines to meet these requirements, and fuel consumption was less in the focus than the emissions of nitrous oxides and soot, hydrocarbons and carbon monoxide. Future legislation will require not only tighter limits in emissions but additionally will set fuel consumption targets. More demanding drive cycles will make it even more difficult to achieve these targets. Additional to measures on the combustion engine, moderate electrification for energy recuperation as well as the supply of electrical generated torque to the drive train will increasingly find its way into modern passenger cars. The presence of an electric machine can be used not only to reduce the fuel consumption but also the emissions of the combustion engine.