Volvo Flywheel KERS system – significant performance gains, with up to 20% less fuel consumption

Volvo Flywheel KERS system – significant performance gains, with up to 20% less fuel consumption
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Volvo is set to test a new system called Flywheel KERS (Kinetic Energy Recovery System), which it claims will make a four-cylinder engine feel like a six-cylinder and at the same time reduce fuel consumption by up to 20%. The company has received a 6.57 million Swedish kronor grant from the Swedish Energy Agency for development, in a joint project together with Volvo Powertrain and SKF.

The Flywheel KERS is fitted to the rear axle – during retardation, the braking energy causes the flywheel to spin at up to 60,000 revs per minute, and when the car starts moving off again, the flywheel’s rotation is transferred to the rear wheels via a specially designed transmission.

The combustion engine that drives the front wheels is switched off as soon as the braking begins – the energy in the flywheel can be used to accelerate the vehicle or to power the vehicle once it reaches cruising speed.

The flywheel’s stored energy is sufficient to power the car for short periods. How it will have a major impact on fuel consumption is this: based on calculations, the combustion engine will be able to be turned off about half the time when driving in a New European Driving Cycle mode.

Since the flywheel is activated by braking, and the duration of the energy storage (the length of time the flywheel spins) is limited, the technology is at its most effective during driving featuring repeated stops and starts, which means busy urban traffic.

Combining the flywheel’s energy with the combustion engine’s full capacity promises a significant boost in horsepower, and with swift torque build-up in attendance, this translates into rapid acceleration.

The flywheel – which spins in a vacuum to minimise frictional losses – that Volvo will use in its test car is made of carbon fibre, and weighs about 6 kg with a diameter of 20 cm. It’s not the first time flywheel propulsion assistance has been tested by the company – a Volvo 240 also did so back in the 1980s, but the heavy steel-based flywheel wasn’t very efficient.

Volvo also isn’t the first manufacturer to test flywheel technology, but it is in applying it to the rear axle of a car fitted with a combustion engine driving the front wheels. If the tests and technical development go as planned, expect cars with flywheel technology to reach the showrooms within a few years, the company says.

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Anthony Lim

Anthony Lim believes that nothing is better than a good smoke and a car with character, with good handling aspects being top of the prize heap. Having spent more than a decade and a half with an English tabloid daily never being able to grasp the meaning of brevity or being succinct, he wags his tail furiously at the idea of waffling - in greater detail - about cars and all their intrinsic peculiarities here.

 

Comments

  • F1 fffanssssss on Jun 01, 2011 at 3:01 pm

    waaaaahhhhhhh… KERS on road cars, Swedish technology goes superb…

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  • hondasan on Jun 01, 2011 at 3:23 pm

    f1 tech in daily car… Audi people?

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    • Flywheel technology was developed for busses in the 1940s, it’s not a F1 development:

      Quote: ‘The concept of a flywheel-powered bus was developed and brought to fruition during the 1940s by Oerlikon (of Switzerland), with the intention of creating an alternative to battery-electric buses for quieter, lower-frequency routes, where full overhead-wire electrification could not be justified.’

      http://en.wikipedia.org/wiki/Gyrobus

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    • DonkeyKong on Jun 01, 2011 at 5:48 pm

      Audi specifically went for Le Mans because they said that F1 tech won’t translate much to cars for daily driving.

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    • Diablo on Jun 01, 2011 at 11:51 pm

      Flywheel KERS was never raced in F1 though Williams intendedn to and invested in its development. If we really want to nitpick, KERS is a small bit of F1 that has some relevance to road cars but remember it was not created by F1. Le Mans has far more number of tech relevant to road cars. Le Mans organisers the ACO actually construct the racing regulations to promote tech development relevant to car manufacturers. Efficiency is the game. The Peugeot and Audi LMP1 diesels even race with oxidation catalyst in the exhaust (diesel catalytic converters) because the lessons learnt will assist their road car emission systems.

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  • Diablo on Jun 01, 2011 at 3:30 pm

    Kinetic energy recovery systems aren’t new concepts to production cars. Essentially what hybrids are. However a flywheel type energy recovery is rare. Porsche started racing theirs and probably will be made available to public. Good to see Volvo getting into this as well.

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    • Jimmy Dean on Jun 01, 2011 at 5:31 pm

      Its not that rare… I’d seen work on an EV bus in 2001 by an American company where regen braking is stored in flywheel. Its better than storing in battery pack because there is a limit how much charging current a battery pack can absorb. By my calculation (given mass and dimension of the flywheel), the kinetic energy that can be absorbed at 60,000 rpm is about 592 kJ and assuming that it takes 10 seconds to to achieve 60,000 rpm…. perhaps about 60 kW (about 80 hp) of braking power from this mechanical KERS system.

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  • I like the statement of “four-cylinder engine feel like a six-cylinder and at the same time reduce fuel consumption by up to 20%” its like a key to revolution to me

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  • armandd on Jun 01, 2011 at 7:11 pm

    The front wheel drive system (engine) is completely separated with the rear (flywheel), so it’s less complex than hybrid cars’ regenerative braking system. I hope that in the future this KERS system will be available as aftermarket part, so that more people can enjoy it!

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  • Carl Wong on Jun 01, 2011 at 9:56 pm

    No battery is needed?? KERS POWER!!

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    • F1 fffanssssss on Jun 01, 2011 at 11:26 pm

      Build Volvo Tough NOT Build Ford Tough… Volvo cars are the toughest cars anywhere, because of over 5 stars rating in Euro NCAP, its best selling cars are SUVs, and puts 4WD system to all cars. The Ford Ranger is NOT enough tough compared to Volvo XC60. Way to go, Volvo cars for every people, build Swedish technology superb, build Volvo tough.

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  • rexis on Jun 02, 2011 at 10:03 am

    With all those weight and cost and life span involved in a battery energy storage system, there is really little reason why not just use a kinetic energy storage if they are able to make it that small.

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