Cars are not very efficient. Lots of energy is lost as heat, noise, and friction as gears turn, brakes heat up, engines roar, and wind drags. But a new technology could transfer the bounces of a bumpy road into energy for the engine.
ZF Friedrichshafen AG and Levant Power Corp. have joined together to produce the first fully-active advanced suspension system that recovers energy and directs it to charge the battery while the car is moving. The bumpier the road, the more power generated. Normal suspension systems encounter a trade-off between a smooth ride and precision handling — ZF and Levant’s design claims to achieve both. Active dampers change the pressure inside of the shock, smoothing out the ride — when there’s a lot motion from bumps, braking, and accelerating, fluid gets pushed through the pump, which drives a motor and creates electricity.
Normally a vehicle’s suspension just dissipates the kinetic energy of bumps in the road through springs, but this new technology provides direct charge to the battery. The initial GenShock design aimed to improve efficiency by 10 percent, and Levant said that a heavy-duty truck using 6 of the shock absorbers could produce enough energy to displace the alternator.
Levant is a company created by former MIT students that developed the GenShock design in 2009, while ZF Friedrichshafen AG is a German auto parts manufacturer. The German company has been making “adaptive damper” systems since 1994, which are suspension systems that actively control each wheel rather than passively reacting to the road. Such active suspension systems normally require energy to operate, but now the power generated by each bump and pitch could more than offset that required by the system, and charge the battery over a bumpy road.
Rolf Heinz Rüger, who runs ZF’s Suspension Technology unit, said “the objective is to develop the world’s first fully active regenerative suspension, make it ready for volume production, and introduce it to the market.”
Gas2 says it’ll be “a while” before the system will go mainstream — likely several years — but it seems a no-brainer for every hybrid and electric vehicle to install this system or one like it to eke out battery charge through energy that is normally wasted. Gas-powered cars also have batteries that get a charge while the engine is running, but they use a belt attached to the engine itself to charge the battery. This causes gas-powered engines to be less efficient, and with most conventional cars using only around 15 percent of the potential energy of gasoline, efficiency comes at a premium.
Most hybrid car drivers will be familiar with the concept of recovering energy from normal car functions because of the increasingly frequent use of brake systems that, when used, transfer heat and friction of normal braking to the battery. As fuel economy standards improve over the next decade, car manufacturers are looking for anything they can do to make cars more efficient.
Volkswagen’s XL1 car design eliminated side mirrors, which could improve aerodynamic efficiency by as much as 5 percent. Tesla Motors’ Model X also had no side mirrors, and the company appears to be up for a legislative fight to change federal safety regulations that require the mirrors.
Using kinetic energy to generate electricity is not limited to automobiles. Runners in the Paris Marathon used piezoelectric generators to charge a battery that powered a light near the finish line earlier this year.