Design of novel tilting electric four-wheelers

EU cities are increasingly congested due to the demand and usage of motor vehicles. Future scenarios for EU urban centers see a modal shift in personal mobility from cars to lighter, smaller, more specialized and environmental-friendly alternatives. Electric L-category Vehicles (ELVs) are viable alternatives that can fulfill the commuter needs due to their small size and light-weight: by consequence the energy requirement, battery size and related costs can be strongly reduced respect to conventional electric cars. However, this modal shift must overcome one main challenge: most car drivers do not consider Lcategory vehicles as a suitable option mainly due to L-vehicle dynamic limitations. To achieve that, the RESOLVE (Range of Electric SOlutions for L-category VEhicles) project, funded in the Horizon 2020 framework - Green Vehicles GV5-2014 call, will develop components and systems aimed to meet the low cost target required for this segment. At the same time, the project will deliver an exciting and attractive ELV driving experience by proposing new concepts (tilting and narrow track), while containing as much as possible the vehicle energy consumption. In this paper, the dynamics analyses carried out to develop the architecture of ELV vehicles are presented. A stability analysis of the vehicles in straight line was firstly carried out and the results were compared to tilting two and three-wheelers for a wide range of speed. A detailed multibody model was developed to simulate the steady-state behavior of the 4-wheelers during turning and to perform further dynamic analyses. In addition, an entire vehicle model including electrical and mechanical components (battery, power electronics, e-motor, driveline, etc.) was developed to assess the ELVs energy needs during reference and real-world driving maneuver. The results demonstrated the feasibility of this novel kind of vehicles, confirming the exciting driving experience typical of tilting vehicles, combined with comfort, low environmental impact and limited energy requirements.