Regenerative Braking Experimental Tests and Results for Formula Student Car

Abstract

In this paper, the tuning process of a regenerative braking system for a full electric Formula Student car is reported. Experimental results will be discussed and recovered energy will be measured. In order to obtain the best tuning some preliminary requirements have been decided: no-slip motion of traction wheels during braking phase, no over current and over voltage of Li-ion cells and the best feeling from the braking pedal for the driver. The main target of the regenerative braking system is to obtain the maximum recovered energy during the Endurance event in a typical Formula Student Competition (FS Germany, Hockenheim ring). First, an accurate estimation of the admissible braking torques with the tires used was carried out, starting from the magic formula of Pacejka of the tires. The maximum electric braking torque that the installed engine can provide at various speeds was then estimated, compatibly with the charging currents allowed by the storage system. Subsequently, a mechanical regulating device for regenerative braking was designed and described here, installed directly on the gear lever system that connects the brake pedal to the brake pumps. The proposed system is able to appropriately delay the entry into action of the hydraulic brake pumps and this delay is mechanically adjustable by acting on threaded pins. In this way, the interval of actuation of the brake pedal which activates only the electric braking can be adjusted and tuned. Finally, the overall project was tested on the track, in order to validate the hypotheses previously calculated and determine the setting capable of optimizing the energy recovered during a test equivalent to the Endurance event, compatibly with the constraints of the installed systems on board.

The Effects of Fluid Sloshing on Different Baffle Configurations in Storage Tanks Transported on Trucks during an Emergency Braking

“…The regenerative braking force according to Martellucci, L. and Giannini, M. [9] shows that during a significant braking, typical of a Formula Student races, the load distribution on the two axles (front and rear) changes according to many parameters related to the kinematics and dynamics of the suspension system. The pitching movement of the chassis, a function of many parameters (and dive, shock absorbers, barycentric axis, etc.…”

Analysis of the Performance and Overall Efficiency of a Formula Student Electric Car

“…To avoid thermal issues [3] [4] that would have affected the tests, regenerative braking has been disabled. Its optimization was the subject of previous work [5]. All the tests were performed with the same tires pressure (measured with cold tires), the same dynamic configuration and the energy storage voltage (4V for each cell)…”

Comparison of Energy Consumption of Different Electric Vehicle Power Systems Using Fuzzy Logic-Based Regenerative Braking

“…However, it has a limited part of the total braking in order to avoid problems that might occur in active driving safety systems [20]. This ratio can also be determined by a fuzzy logic controller, which depends on different essential factors such as state of charge (SOC), brake pedal position (BPP), braking force, speed of the vehicle, and temperature of the battery [21,22].…”