In order to solve the range problem that electric vehicles still have, vehicle concepts such as plug-in hybrid vehicles are very promising. They combine the advantages of the combustion engine and the electric motor, so that the local emission problem in urban areas can be solved. However, if the vehicle is mainly used for short distances, fuel aging can occur due to higher storage time in the fuel tank.In this work a sensor-based concept for determination of the fuel quality is presented. For this purpose, a prototype was developed in which aging fuels can be determined by measuring the real and imaginary part of the permittivity. By determining the frequency-dependent permittivity signal of the sensor low- and high-molecular oxidation products in fuels could be distinguished.Since the combustion and emission behaviour of the engine is given by the fuel mixture, the determination of the fuel composition offers further optimization potential in order to reduce emissions: The engine management in the vehicle is usually adapted on reference fuels of constant quality. Variable fuel compositions, given by the oil deposits and the additional conversion process for the production of advanced fuels, have not yet been taken into account in this adaptation strategy. As an additional task, a multisensory approach is introduced in this work in which the fuel composition can be determined.Overall, the sensor system offers the potential for continuous fuel monitoring in plug-in hybrid vehicles in order to be able to ensure a contribution to the safe and sustainable operation of such vehicles.
