Hoovey689

iTrader: (16)

Volvo testing F1-style KERS system, cites 25% fuel economy bump

Gallery:
http://www.autoblog.com/photos/exper...photo-5841823/

Volvo has been experimenting with flywheel propulsion systems since the eighties, but only recently has technology caught up with the possibility of real-world applications. In 2011, the Swedish carmaker was granted 6.57 million Swedish kronor (about $1M US) by the Swedish Energy Agency to work on a kinetic energy recovery system with Swedish bearing company SKF. Before it began trials, Volvo expected the fuel savings to be as high as 20 percent. After trials conducted last year on public roads the results were even better, Volvo finding that a KERS-equipped four-cylinder turbo performs like a six-cylinder turbo but gets up to 25-percent better fuel economy. It calls KERS "a light, cheap and very eco-efficient solution."

The test vehicle was an S60, its ICE driving the front wheels while the KERS – weighing six kilograms, measuring about 20 centimeters across and using a carbon fiber flywheel – was attached to the rear axle. Under braking, the four-cylinder engine is shut off and the KERS gathers rotational energy, spinning at up to 60,000 revolutions per minute. The stored energy is then used to get the car going again or to assist at cruising speeds. It's the same kind of vacuum-sealed flywheel design used by Audi in its R18 etron quattro, but with the opposite arrangement – in the Audi the diesel V6 drives the rear wheels, the KERS drives the front wheels.

Like the units in Formula One, it provides an additional 80 horsepower. When working with the four-cylinder ICE, the S60 with KERS can do the 0-62 mph dash in 5.5 seconds, a full 1.1 seconds faster than the S60 with the 3.0-liter T6 engine and all-wheel drive.

As we expect with hybrids, the greatest fuel savings came in urban environments with a lot of braking, Volvo suggesting that the combustion engine could be shut down "about half the time" on the New European Driving Cycle.


http://www.autoblog.com/2013/04/29/v...-economy-bump/

Hoovey689

iTrader: (16)

Mmm!! Sounds delightful

Coconut

Heard about KERS but never really understood how it works. Either way it looks very promising. Fuel saving AND more power? Yes please

geko29

Interesting that the flywheel is carbon fiber. The energy capacity of a flywheel is determined by its rotating mass, which makes it kind of odd that they use one of the lightest materials known to man.

Sulu

The energy capacity of a flywheel is dependent upon its mass and its rotational speed (rpm). A heavy metal flywheel will have the mass but it will also take a long, long time before it starts to spin at significant rpm to store some energy. It takes a long time to store enough energy to use.

The CF flywheel, being lighter, takes much less energy to spin up to high rpm. It takes a much shorter time to store enough useful energy. This is what you need, especially in city driving, which is when it is most needed in a driving cycle: quickly store enough energy during short deceleration (coasting and braking) runs that can then be very quickly used to accelerate away from the next stop light (when an internal combustion engine is least efficient).

And if the flywheel energy storage system is more efficient than a battery -- smaller in size, lighter, and stores and dissipates the stored energy quicker than an electric hybrid battery -- the KERS hybrid vehicle is better than a gas-electric hybrid vehicle.

Hoovey689

iTrader: (16)

KERS is great. If it becomes cheaper through advancements, perhaps it can become more common