At its most basic level, the task of suspension dampers is to absorb energy. Specifically, the kinetic energy created by driving over a road surface, and all the associated imperfections, pot holes and speed bumps. The majority of that energy is wasted, as it’s lost in the form of heat - but what if it could be harnessed? That’s exactly what Audi is hoping to do with a suspension system it’s developing, rather unfortunately called ‘eROT’.
In this system, a lever arm absorbs the movement of the wheel carrier, and through a series of gears transmits the movement to an electric motor, which then generates electricity. This free juice is sent to a 48-volt ‘substation’ - a system Audi already uses in the SQ7 (below).
How much electricity depends on how crappy the road surface is. Audi’s testing revealed an average of about 100 to 150 watts on German roads, ranging from 3 watts on a newly surfaced autobahn to 613 watts on a “rough secondary road”. Since the energy created means the engine has less battery charging to do, you’ll burn less fuel and emit less in the way of C02 - a drop of around 3g/km is what we can expect.
This suspension is more about the whole kinetic energy harnessing thing, too. Using trick software, it’s able to give a soft compression followed by a stiff rebound. Should this all work how Audi wants it to, it’d be the suspension equivalent of having your cake and eating it: dampers that don’t trade composure for comfort, or the other way around.
It’s early days, by the company does state that “its use [eROT] in future Audi production models is certainly plausible.” There is a caveat - the models in question will need to run the 48 volt system, but as that’s something expected to be rolled out to many more models in the near future, these clever dampers might be a common fit in the Audi stable before long.