Shock absorbers that generate electricity, which are being developed by Cambridge, MA-based Levant Power, can lower fuel consumption by 1.5 to 6 percent, depending on the vehicle and driving conditions. The system can also improve vehicle handling.

Pothole power: This shock absorber turns vibrations and jolts from rough roads into electricity. Credit: Levant Power

Levant has demonstrated the technology in road tests with a Humvee and will expand testing to trucks, buses, and other vehicles this summer. The shock absorbers look like conventional ones from the outside, except for a power cord coming out of one end, and they can be installed in ordinary vehicles by mechanics. They plug into a power management device that can also manage power from other sources, such as regenerative braking systems, thermoelectric devices that convert waste heat into electricity, or solar panels. The power is then fed into the car's electrical system to reduce the amount of load on the alternator.

As in a conventional shock absorber, the Levant technology uses a piston moving through oil to damp down movement. But Levant has developed a modified piston head that includes parts that spin as it moves through the oil, turning a small generator housed within the shock absorber. To improve vehicle handling, the power controller uses information from accelerometers and other sensors to change the resistance from the generators, which stiffens or softens the suspension. For example, if the sensors detect the car starting a turn, the power controller can increase the resistance from the shock absorbers on the outer wheels, improving cornering, says David Diamond, the vice president of business development at Levant.