2020 is still a couple of years away, but Volvo has already given car and car tech enthusiasts something to look forward to when the time comes. The Swedish automaker is expected to roll out its flywheel system and include it in its production cars after that year, according to one of its engineers.
U.K.’s Autocar recently reported that Volvo is testing a British-designed flywheel-based hybrid system which can lower fuel consumption by over 25 percent. It is called the Flybrid KERS (Kinetic Energy Recovery System) and it was developed through the partnership of Volvo and Torotrak’s Flybrid Automotive.
The Flybrid KERS is fitted to the rear axle of the test car. When the driver hits the brakes, like when he/she is approaching a red light, the flywheel would continue spinning. The kinetic energy will then transfer from the wheels to the KERS on the axle not powered by the engine. The energy will stay in the flywheel for about 20 minutes before it starts to disperse.
When the driver hits the accelerator, the stored energy moves back to the wheels with the help of a custom designed transmission, and it can be used to either lower carbon emissions or boost performance. The energy from KERS can help propel a vehicle without the engine when it is time to drive.
The flywheel system is based on a traditional flywheel and runs a maximum speed of 60,000 rpm and can produce 80 bhp. The flywheel, which is placed within a true vacuum, is made more efficient. It is lightweight—weighing a bit over 13 pounds—and manufactured with steel and carbon fiber. It is designed in such a way that the engine is turned off the moment the driver starts to brake. The prototype KERS weighs about 130 pounds.
The flywheel transmits energy with the help of a Torotrack CVT, which features tilting rotary discs that make the transfer possible. These discs power a set of gears to slow down drive output and in turn power the rear axle.
The company started testing the technology last year on public roads with an S60 sedan as its test car. The 254-horsepower prototype can go from 0 to 62 mph in 5.5 seconds, making it quicker than the S60 T5 production model.
According to Volvo, the S60 prototype can get a 10-second boost when the driver steps on the pedal but even eight seconds of gentle braking can already power up the KERS. Eight seconds is fast compared to the amount of time a conventional electric hybrid vehicle needs to recharge its batteries.
The Flybrid KERS is also less expensive compared to a standard battery-electric hybrid. Not only is it cheaper to produce, but it is also affordable to maintain.
This system is expected to be most useful in urban traffic, as the driver will often use the brakes on the road. It is easy to surmise that the energy recovery system will not be used as much in expressways but Flybrid engineers refuted this, saying that the flywheel can still be recharged even when the engine is driving the wheels.
Photo credit: motorauthority.com