Engineers from the University of Wisconsin-Madison along with a collaborator from China have created a new nanogenerator that harnesses energy from the friction caused by rolling tires.
Xudong Wang has developed a new way to harvest energy from rolling tires (Credit: The College of Engineering)
As a novel energy reusing method, the nanogenerator could be potentially used by automobile manufacturers to improve the efficiency of their vehicles.
The first of its kind, nanogenerator was published in the Nano Energy journal. The research was carried out by Xudong Wang, the Harvey D. Spangler fellow and an associate professor of materials science and engineering at UW-Madison, and his PhD student Yanchao Mao for about one year.
Based on the triboelectric effect, the nanogenerator can harness energy resulting from the electric potential created between a vehicle's wheels and the pavement. The triboelectric effect is the electric charge generated due to the rubbing or contact of two dissimilar objects.
Wang stated that the nanogenerator enables an excellent means of exploiting energy that is generally wasted due to friction.
The friction between the tire and the ground consumes about 10 percent of a vehicle's fuel. That energy is wasted. So if we can convert that energy, it could give us very good improvement in fuel efficiency.
The nanogenerator operates based on an electrode attached to a portion of the tire. When this part touches the ground, an electrical charge is produced by the friction between the two surfaces, resulting in a kind of contact electrification known as the triboelectric effect.
Wang and his colleagues demonstrated the concept using a toy car integrated with LED lights, during the initial stages of the experiments. Then they fixed an electrode to the car wheels, and the LED lights were made to turn on and off as the wheels rolled on the ground. Sufficient amount of energy was generated by the movement of electrons due to friction. This enables harnessing and reusing the energy lost to friction.
Regardless of the energy being wasted, we can reclaim it, and this makes things more efficient. I think that's the most exciting part of this, and is something I'm always looking for: how to save the energy from consumption.
Further, the researchers proved that the quantity of energy collected is a function of the weight and the speed of the car. Hence, the total amount of energy harnessed can differ according to the vehicle. Wang reported an increase in the average vehicle's gas mileage by 10%, and 50% friction energy conversion efficiency.
"There's big potential with this type of energy. I think the impact could be huge," Wang said.
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