DLR@UniST - Synergies emerging from integrating four individual electric drives in a lightweight chassis controlled by intelligent driving strategies

Abstract

In the context of future electric vehicles, new requirements and restrictions but also larger degrees of freedom have been revealed for vehicle concepts. To meet the revised factors, new approaches are necessary as well as an integral view of the vehicle and its subsystems. As a consequence the Institute for Vehicle Concepts at DLR e.V. is developing an innovative electrically driven chassis system along with the Institute for Internal Combustion Engines and Automotive Engineering of the University of Stuttgart. This system consists of an innovative suspension concept and electric motors that are positioned close to the wheel hub. The goal is to outline the synergies between the lightweight design of chassis and motor, the individual drives and a driving strategy that focuses on energy efficiency and driving safety. Having individually driven wheels opens up new possibilities for vehicle dynamics control strategies. This includes the associated increase of driving safety, comfort and energy efficiency through the targeted distribution of power and recuperation. On the other hand, the positioning of the motors close to the wheel increases the unsprung mass. This challenge can only be met with consistent lightweight design of all chassis components. The unsprung mass can be reduced through concept-level lightweight design, integration of functions, shape optimization and of course lightweight materials. A new suspension concept that promises significant weight reduction by integrating the motor in an intelligent way is presented. By applying all available lightweighting strategies the driving resistances are reduced and the flow of forces in the suspension is simplified and thereby improved. The drive concept is characterized by its compact design, through which it is possible to position a large part of the suspension compo-nents within the wheel. As a consequence, the useful space within the vehicle is pre-served and maximized.