A high-efficiency energy regenerative shock absorber for powering auxiliary devices of new energy driverless buses

Abstract Many countries are gradually adopting the latest energy driverless buses to reduce harmful environmental emissions, mainly in the transportation sector. The power supply is the main obstacle to developing new energy driverless buses while assuming the absence of battery technology advances. This paper proposes a new energy regenerative shock absorber to capture the wasted kinetic energy of the vehicle suspension system and produces electrical power. The regenerative shock absorber is divided into four modules: vibration energy capture module, motion conversion module, generator module and electric energy storage module. The random vibration of suspension, caused by certain factors, such as rugged roads and speed variation, acts on the vibration energy capture module. The motion conversion module mainly consists of two helical racks with opposite threads and converts the bidirectional vibration into unidirectional rotation of the generator. The utilization of helical gears with different diameters makes the damping coefficients different, so that the regenerative shock absorber can take full advantage of elastic elements to improve vehicle comfort during compression strokes, and quickly absorb vibration during extension strokes. The generator module generates electricity and the electric energy storage module accumulates the electricity in the supercapacitor. A prototype was fabricated, and the power generation performance of the regenerative shock absorber was evaluated by bench test under different sinusoidal excitations. At input sinusoidal displacement of 7 mm and 2.5 Hz frequency, the average output power of 4.25 W and maximum and average efficiencies 65.02% and 39.46% were calculated. The results demonstrate that the designed regenerative shock absorber can effectively scavenge renewable energy and apply it to the new energy driverless buses.