A nano-generator harvesting energy from the friction of rolling tyres could improve the efficiency of automobiles.
The device, described in the journal Nano Energy, was created by engineers from the University of Wisconsin-Madison, USA, (UW-Madison) in cooperation with a Chinese firm.
The nanogenerator relies on the so-called triboelectric effect, an electric charge resulting from the contact of two distinct materials. This charge can be harnessed by an electrode integrated into a section of a tyre and could be used to power the car's systems, thus recovering at least a portion of the energy wasted because of friction.
"The friction between the tyre and the ground consumes about 10 per cent of a vehicle's fuel," said Xudong Wang, an associate professor of materials science and engineering at UW-Madison, one of the authors of the invention.
"That energy is wasted," Wang said. "So if we can convert that energy, it could give us very good improvement in fuel efficiency."
During their experiments, Wang and his PhD Yanchao Mao used a toy car fitted with LED lights and the nano-generator to prove the concept. As they were driving the toy car around, the LED lights were flashing based on the availability of the charge from the tyres.
"Regardless of the energy being wasted, we can reclaim it and this makes things more efficient," Wang said. "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."
The researchers also determined that the amount of energy harnessed is directly related to the weight of the car, as well as its speed. Therefore the amount of energy saved can vary depending on the vehicle. Wang estimates that an average car would be able to travel 10 per cent further with such technology.
"There's big potential with this type of energy," Wang said. "I think the impact could be huge."