Abstract
Research Objective
Automobile manufacturers developing electric vehicles regularly convert existing internal combustion engine vehicles into new electrically driven designs. One effect of this is that the new requirements and restrictions involved in automobile electrification are not met, but also that its larger degrees of freedom are not fully utilized. To meet the revised conditions, new approaches are necessary, as well as a holistic view of the vehicle and its subsystems.
Methodology
In the following paper the development of a suspension for electrically driven vehicles is shown. The suspension is developed through the application of a methodical procedure model that was previously developed at the German Aerospace Centre. The process model addresses the altered boundary conditions brought by electrification, while enabling the development for electro-mobility specific suspension of road vehicles. An example created using this model is the LEICHT, an innovative suspension for urban vehicles. LEICHT stands for the primary characteristics of the suspension: Lightweight, Energy-efficient, and Integrative Chassis with Hub-motor Technology.
Results
The LEICHT is developed using computer aided design, simulation and multi-body dynamics software. The paper shows the results of the virtual product development which contain the methodical construction process (CAD) including a material database selection step, the chosen simulation strategy (FEM), as well as the strength verification for different material combinations. In addition the vehicle dynamics (MBS) of the LEICHT during a specific driving maneuver are outlined (spring deflection, slip angle difference, etc.) and compared to suspensions from the state of the art. All design model layouts are clearly and concisely described. Following the virtual product development, the competitiveness of the proposed LEICHT-suspension/drive module is demonstrated by comparing it to solutions from the current market using quantifiable criteria such as the unsprung mass, packaging and vertical dynamics. Limitations of this study The important limitations of the paper can be seen in the mature design of the LEICHT. Measures to improve the suspension’s design and its behavior are discussed as well as the required steps for the targeted serial vehicle application. Those steps include the real validation of the innovative components of the LEICHT on different test benches (chassis dynamometer, chassis test bed) as well as its integration in research vehicles that are planned from 2015-2016.
What does the paper offer that is new in the field including in comparison to other work by the authors?
Previous works of the authors mainly focus on establishing the methodical procedure model for the development of vehicle suspensions whereas this paper gives insights into its application including validated data such as the concepts strength verification, the materials used or the suspension’s behavior with respect to the full vehicle.
Conclusion
An innovative suspension concept has been developed that was designed especially for the requirements of electro mobility and that promises significant competitive advantages. An overview is given in the results of the design process (most notably material selection, CAD, FEM and MBS).
Key Words: suspension, drive, electro mobility, design