ZF's GenShock energy-recovering suspension technologyEnlarge Photo
Doing more with what you have is one of the cornerstones of increasing efficiency, and a new suspension technology from ZF will take that mantra to the next level.
Cars are inherently pretty energy-inefficient. Engines do better job of turning the energy in fossil fuels into noise and heat than they do movement, and most of that forward movement is lost completely and dissipated as heat when you brake. Your transmission loses even more energy through friction, as does every other rotating or oscillating component as you drive down the road--including your suspension.
ZF and Massachusetts-based Levant Power's new technology goes some way to redressing this balance. Called GenShock, it uses the oscillations of a car's shock absorbers to feed energy back to the car.
Normal active dampers use an electric motor and an electrohydraulic gear pump to control the flow of fluid in shocks to adjust your damping rate. Press a button and you get a sporty, stiffer feel, press another and the car glides over bumps. Or it can do both at once--adjusting near-instantaneously to provide flat cornering but a supple ride over rough surfaces.
GenShock essentially reverses this process. As the ground you're covering pushes the piston in the damper up, forcing fluid past the electrohydraulic gear pump. This turns the motor--which if you paid attention in physics class, now becomes a generator. Thus suspension movement is turned into useful electricity, reducing alternator load and therefore helping your car use a little less fuel.
Ironically it could end up being most effective on the hardest-worked vehicles. A pickup truck regularly covering rough ground will generate more power than a hybrid gliding along a freeway, for example.
With over 14 million of ZF's existing Continuous Damping Control active shocks already used around the world, the small benefits of each GenShock damper could add up to enormous collective efficiency gains when it eventually hits the market.