In this paper, we present our work towards an auditory display that is capable of supporting a fuel-efficient operation of vehicles. We introduce five design approaches for employing the auditory modality for a fuel economy display. Furthermore, we have implemented a novel auditory display based on one of these approaches, foussing on giving feedback on the engine’s optimal rpm range, which is a major factor for eco-driving. Finally, we report on the development of a simple but physically realistic car simulator, which allows for a reproducible evaluation of prototype auditory displays as well as a comparison to state-of-the-art visual fuel efficiency indicators.