Tony O'Kane | Feb 3, 2009

With practically every hybrid on today's roads rocking some kind of regenerative braking system, we're all pretty familiar with the fuel-saving and energy-recouping technology by now.

By converting the car's kinetic energy back into stored (electric) energy, regenerative braking allows vehicles to extend their range by recapturing energy that would normally be wasted as heat. The physics behind regenerative braking is simple, but why stop at brakes? After all, a car's wheels aren't the only things that move...

Enter Tufts University and its pioneering regenerative shock absorber system. It's not exactly a brand-spanking new concept mind you, for Ronald Goldner originally developed the idea over a decade ago during his time as an engineering professor at Tufts. What is new, however, is that American firm Electric Truck LLC has stitched up the exclusive commercial rights to the technology, with a view to bringing it to road-going vehicles in the near future.

Goldner's regenerative shock absorber resembles a conventional gas or oil-filled strut from the outside, but is completely different under the skin. A stack of permanent magnets is housed within the shock absorber rod, while copper stator windings are coiled around the cylinder itself. As the rod moves up and down within the cylinder the magnets induce a current in the stator, which is then stored in an on-board battery. Presto, free energy.

Current estimates say regenerative shock absorbers can increase the total driving range of any existing hybrid or electric vehicle by 20 to 70 percent, with a negligible increase in weight. It's a bold claim, but if Professor Goldner and Electric Truck's maths is on the money, then we've no doubt that regenerative damping will be the next big buzzword within the green car movement.

We've yet to hear of a major manufacturer that's planned to adopt this energy-saving tech, but given the system works best with heavier vehicles we can expect to see it rolled out on commercial vehicles first - most likely ones wearing an Electic Truck badge. Watch this space.

[Tufts University, via Gizmag]

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