On the way to emission-free mobility, future fuels must be CO2 neutral. To achieve this, synthetic fuels are being developed. In order to better assess the effects of the new fuels on the engine process, simulation models are being developed that reproduce the chemical and physical properties of these fuels.
In this paper, the fuel DMC+ is examined. DMC+ (a mixture of dimethyl carbonate (DMC) and methyl formate (MeFo) mainly, characterized by the lack of C-C Bonds and high oxygen content) offers advantages with regard to evaporation heat, demand of oxygen and knock resistance. Furthermore, its combustion is almost particle free. With the aid of modern 0D/1D simulation methods, an assessment of the potential of DMC+ can be made.
It is shown that the simulative conversion of a state-of-the-art gasoline engine to DMC+ fuel offers advantages in terms of efficiency in many operating points even if the engine design is not altered. This is mainly due to the higher knock resistance and the lower temperatures in the intake stroke resulting from the higher amount of evaporated fuel. For a fixed amount of fuel energy, a lower air mass flow rate is needed, making the fuel particularly interesting for down-sizing concepts.
Therefore, the engine design is adapted for the new fuel to take full advantage of the fluid properties. In a first step, the adaptions include the compression ratio, the engine displacement and the turbocharger matching. A considerable efficiency gain in the whole operating range can be demonstrated, making DMC+ a highly promising prospective for future SI engines.