Undergraduate students at the Massachusetts Institute of Technology (MIT) have found a way to generate electricity by harnessing energy from small bumps in the road.
The researchers say that a shock absorber invented by them can make this possible, while smoothing the ride more effectively than conventional shocks.
The new system also has a fail-safe feature-if the electronics fail for any reason, the system simply acts like a regular shock absorber.
Having already courted the U S military and several truck manufacturers, the students are hoping to initially find customers among companies that operate large fleets of heavy vehicles.
Shakeel Avadhany and his colleagues claim that they can improve overall vehicle fuel efficiency by up to 10 percent by using the regenerative shock absorbers.
Not only would improved fuel efficiency be a big plus for the army by requiring less stockpiling and transportation of fuel into the war zone, but the better ride produced by the actively controlled shock absorbers make for safer handling, the students say.
"If it's a smoother ride, you can go over the terrain faster," says Zack Anderson, a senior team member.
They have even obtained a vehicle for testing purposes from the company that produces Humvees for the army, and is currently working on development of the next-generation version of the all-purpose vehicle.
Anderson has revealed that they undertook this project because "we wanted to figure out where energy is being wasted in a vehicle."
Considering that some hybrid cars already do a good job of recovering the energy from braking, the researchers looked elsewhere, and quickly homed in on the suspension.
They began by renting a variety of different car models, outfitting the suspension with sensors to determine the energy potential, and driving around with a laptop computer recording the sensor data.
Anderson says that the team observed that "a significant amount of energy" was being wasted in conventional suspension systems, "especially for heavy vehicles."
Upon realising the possibilities, he says, the team set about building a prototype system to harness the wasted power.
According to the research team, their prototype shock absorbers use a hydraulic system that forces fluid through a turbine attached to a generator.
An active electronic system, which optimises the damping, controls the system to provide a smoother ride than conventional shocks, while generating electricity to recharge the batteries or operate electrical equipment.
The students' tests have thus far shown that in a 6-shock heavy truck, each shock absorber can generate up to an average of 1 kW on a standard road.
They say that this is enough power to completely displace the large alternator load in heavy trucks and military vehicles, and in some cases even run accessory devices like hybrid trailer refrigeration units.
They are currently carrying out tests with their converted Humvee to optimise the system's efficiency.&13;