The future of mobility presents various challenges. For the future CO2 targets, savings in the existing fleet are necessary. In this paper and the accom-panying poster, the project reFuels- Rethinking Fuels is introduced and results of the developed gasoline and diesel fuels are presented. The aim of the project is to enable the use of fuels from renewable sources via BtL and PtL pathways as drop-in components to fossil fuels for use in the existing vehicle fleet. For this purpose, it is shown how the gasoline fuel blend G40 with regenerative fuel com-ponents produced from biomass has advantages in particle behavior in RDE tests compared to conventional fossil gasoline. In single-cylinder tests, a significantly reduces proportion of aromatics larger than or equal to C9 in the optimized bi-oliq® fuel leads to improved particle emissions. Tests with diesel and compo-nents from regenerative sources (PtL and BtL), which mixture was within EN 590, show no adverse thermodynamic behavior but advantages from a raw emission point of view. On production engine at cold start conditions at -7 °C, paraffinic diesel shows improved particulate emissions under transient driving maneuvers, especially in idling phases, compared to fossil diesel.