You might associate the Kinetic Energy Recovery System [KERS] with high-end Formula 1 race cars, but Volvo isn’t leaving it just for the track.
In fact, many track-tested technologies find their way into production vehicles, such as dual-overhead camshafts and tire technology. Volvo’s S60 KERS engineering prototype is one way that Volvo is approaching performance and fuel economy as emissions regulations get tighter.
Like all hybrid vehicles, the most popular of which are hybrid electric vehicles, the purpose of the kinetic energy recovery system is to recover energy that might otherwise be lost while slowing down the vehicle. In a hybrid electric vehicle, this energy is stored electrochemically in the rechargeable battery pack. In a hybrid KERS vehicle, this energy is stored in a flywheel.
In both cases, whether the energy is stored electrically or kinetically, this energy is ready to release on demand the next time that it is needed to accelerate. One of the key benefits of Volvo’s KERS module is it’s weight and cost savings over comparable hybrid electric systems. The flywheel in the Volvo S60 prototype weighs just 13# [the whole system weighs about 132#] and generates up to 30kW spinning at 60,000rpm, which is kept on reserve for up to thirty minutes after the last deceleration.
The kinetic energy recovery system in the Volvo prototype holds about 500W/kg, which isn’t impressive by battery standards, but is far lighter and less expensive than comparable battery technologies. Volvo hasn’t released prices or when they might include the technology in future models. They do state that KERS could reduce fuel consumption by up to 25% by reducing weight and the number of cylinders in the engine.