If you think about it, we're surrounded by all kinds of energy, just waiting to be harnessed. That dog that just walked by, wagging his tail — think how many iPhones that tail's kinetic energy could be recharging! Audi's finally getting wise to this, and is working on harnessing the energy from suspension motion.
According to Audi's R&D chief, Dr.Ulrich Hackenberg, Audi is well along with research into reclaiming motion from suspension components and turning it into storable energy. Conceptually, this isn't that different from the regenerative braking common on hybrids today. Audi is potentially calling the system a 'generator suspension.'
In an interview given to Autoexpress UK, Hackenberg said of the system:
What people don't realise is that dampers get very hot. When working hard over a bumpy road, the dampers are perhaps 100 to 125 degrees. This energy is wasted as heat into the atmosphere. So, we will replace the suspension with a generator.
The mention of heat is a bit curious here, suggesting that the energy may be harnessed via the heat produced, though I'm not really sure how likely that is. Some sort of mechanical linkage to convert the suspension travel to rotational motion to drive a generator could be possible, as well as the admittedly more exotic route of using piezoelectric components that produce electricity when compressed. I'm really just guessing on that last one, but I think it could be an interesting possibility.
The reclaimed energy would most likely be stored in a battery or capacitor, and could be used to either drive an electric motor, as in a hybrid car, or perhaps used to offset the drag on the engine from the alternator, as Mazda's iEloop system works.
Hackenberg also hinted at the possible performance-enhancing qualities of the new suspension system, saying
Because we can send energy back into the damper, you will have an independently variable suspension. This can [compensate for body] roll.
It's an interesting idea, and if there's ambient energy just being wasted, why not try and get it back? I'm curious to see what this turns out to be.