Development of a Flywheel Hybrid Power System in Vehicles without the Electric Drive Device Rated Capacity Limit

At present, most studies are focused on converting the vehicle kinetic energy into electrochemical energy for battery storage. During each deceleration period, the kinetic energy is first converted into electromagnetic energy and then stored in the chemical form before being released as the kinetic energy in next acceleration period, which leads to a low transmission efficiency. Secondly, the efficiency of the kinetic energy recovery is limited by the rated capacity of electric drive devices. Thirdly, a single-axis front-drive electric powertrain can only recover the kinetic energy of front wheels. The system proposed in this paper, which included a flywheel, an electromagnetic coupler, and two gear pairs, was arranged in the rear axis. This new configuration could recycle the kinetic energy of the rear wheels for front-driving vehicles. Most of the energy between the wheels and the flywheel was transmitted in the form of mechanical energy, and the power transmitted by the mechanical port of the electromagnetic coupler was not limited by its rated power. Moreover, the battery only needs to recover the slip power of the coupler. Finally, a test bench based on the proposed system was designed and built under deceleration and cruising conditions. The experimental results also proved the functionality of the proposed system