Impact of lightweight design on energy consumption and cost effectiveness of alternative powertrain concepts

This study analyses the impact of weight reduction on the energy consumption and related costs for different advanced electric powertrain concepts. Several hybrid architectures (parallel/serial hybrid, with/without external charging) and a full battery electric vehicle are assessed and compared to a conventional car with internal combustion engine. To evaluate the effects of lightweight on fuel economy a large set of parameter variations was performed applying a vehicle simulation tool. The simulation results were integrated in a total cost of ownership model to analyze the implications on the cost efficiency from a user perspective. The assessment shows that the potential to reduce the energy consumption through lightweight decreases with increasing degree of electrification. As a consequence the savings of operating costs in EUR/km per kilogram saved are smaller for EVs than for ICEs. However, the conclusion changes if indirect effects of lightweight (e.g. potential resizing of the battery capacity) are taken into account. The outcome of this assessment will help decision makers in the automotive industry to gain a better understanding to which extent investments in weight reductions are effective for future powertrains and which additional effect should be considered.