The Kinetic Energy Recovery System (KERS) was introduced to the world during the 2009 Formula One racing season. KERS allowed the race cars to gain some extra horsepower by pressing a button on the steering wheel. This made the racing much more exciting as the extra horsepower resulted in more passing opportunities. In 2010, only a handful of teams were using KERS. In 2011, most of the teams have adopted the technology.
The way KERS works is ingenious. A flywheel is attached to the brakes. When the car brakes, energy is sent to the flywheel making it spin. The energy from the spinning flywheel can be stored and used to help power the wheels when the car starts moving again.
On May 26, Volvo announced that they are developing a KERS system for road cars. Unlike Formula One, the Volvo version of KERS will always function. There will be no buttons for the driver to push, no opportunity to engage it at an opportune time while passing a semi-trailer on the highway. Volvo is not interested so much in the extra speed KERS can provide, but in the fuel savings it can promote.
KERS would supply most of the power to accelerate from a stop up to cruising speed. In the city, where stop-start driving is common, this means a significant reduction in fuel consumption and emissions. It is the environmental impact of KERS technology that has convinced the Swedish government to fund Volvo's development of KERS.
Derek Crabb, vice-president of power-train engineering at Volvo, noted that, “The flywheel technology is relatively cheap.” He pointed out that the system can be used in the vast majority of vehicles Volvo manufactures without significantly impacting the sticker price.
The KERS technology Volvo is developing will enable the flywheel to spin at around 60,000 rpm in a vacuum. When used, it will give the car up to 80 extra horsepower. This will significantly reduce the time from 0 – 100 km/h. It should be noted, however, that the flywheel can only supply this extra energy as long as it continues to spin. If it stops spinning, the car will have to get up to cruising speed solely on the power provided by the engine.
This isn't new technology, flywheels have been around for centuries storing power and providing energy in any number of applications. It simply hasn't been applied to automotive technology until recently.