The basic setup called for a flywheel KERS to be fitted to the free axle of a car.
When approaching a red light, the driver would hit the brakes like normal.This would cause the flywheel to spool up and keep spinning until the lights turn green and the driver hits the accelerator.
At this point, the flywheel's rotation is transferred to the rear wheels via a specially designed transmission, giving the car a little boost of energy off the line.
Volvo has announced that it has now completed extensive testing of the technology on public roads, using an S60 sedan as the test vehicle.
According to the automaker, the results show that the technology combined with a turbocharged four-cylinder engine has the potential to reduce fuel consumption by as much as 25 percent compared with a turbocharged six-cylinder engine--while offering comparable performance.
The energy stored in the flywheel is equivalent to an extra 80 horsepower. And when being transferred back to the wheels, swift torque build-up means rapid acceleration. The S60 test car would accelerate from 0-62 mph in about 5.5 seconds--remember, this is a turbocharged four-cylinder model we’re talking about.
Researchers found that the system works best in urban environments, which makes sense since the duration of the energy storage (the length of time the flywheel spins) is limited. In addition, researchers found that the stored energy was sufficient to power the car for short periods, meaning the engine could be switched off for as much as 50 percent of the time.
But the benefits don’t end there. Compared to a conventional gasoline-electric hybrid, Volvo’s flywheel KERS is lighter, cheaper and easier to maintain.
Now that the technology has proven successful in one of its existing models, Volvo will start tests in prototypes for its upcoming models and further evaluate the performance before potentially putting the technology into production.