Volvo has announced plans to develop and test a new flywheel kinetic energy recovery system (FKERS).
While this doesn't sound terribly exciting, Volvo says the FKERS is "a light, cheap and very eco-efficient solution that makes a four-cylinder engine feel like a six at the same time as fuel consumption drops with up to 20 percent."
The details are fairly technical, but the FKERS is fitted to the rear axle and collects rotational energy during deceleration. When the car starts moving again, the rotational energy is sent to the rear wheels through a specially-developed transmission. This setup allows the car's engine to be deactivated during deceleration and launch (ie: moving away from stop light) to improve fuel efficiency.
If everything goes according to plan, the company will begin testing the system later this year with the hopes of launching it "within a few years."
Check out the press release for additional information