Can we harvest energy from the suspension of vehicles?
Lei Zuo, a professor of mechanical engineering in Virginia Tech's College of Engineering, has been investigating this matter. Zuo indicates that three opportunities exist for recovering or generating energy while driving, being heat given off by the engine, the energy absorbed during braking, and the energy dampened by shock absorbers. Zuo states that car’s shock absorbers can provide 100 to 400 watts of energy on normal roads and more on rough roads. This can increase fuel efficiency by between 1 and 5 percent, which would result in fuel savings of $ 13 billion to $ 19 billion.
The energy-harvesting shock absorber translates vertical vibrations from the suspension into rotational motion that turns a generator. This generator provides electricity to the car’s battery or electrical devices, which reduces demand on the alternator. A combination of gears allows motion in both directions to be changed into electricity, doubling the energy that can be recovered. This allows the generator to work at a constant speed and decreases the load on the gear teeth, resulting in the system being more efficient and reliable. The generator also keeps rotating after the vibration has stopped, increasing the amount of energy recovered. Zuo is confident that the system can reach 85 percent efficiency. The new devise can also be retrofitted without changing anything in the car. Source: http://www.vtnews.vt.edu/articles/2015/08/080415-ictas-zuosuspension.html