Volvo flywheel KERS

[mx_tifoso]

I'm not sure of how new this is, but Volvo is claiming an increase in fuel efficiency of up to 25% with their flywheel KERS.

So, how are they improving fuel efficiency by up to 25 percent? Well, Volvo’s solution is KERS – kinetic energy recovery system. Their system, known as 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. When the car starts moving off again, the flywheel's rotation is transferred to the rear wheels via a specially designed transmission.”

This is complimented by the fact that the internal combustion engine (ICE) shuts off as soon as the driver applies the brakes, so that the energy of the flywheel can be stored and then used when the car sets off again. The Swedes claim the system works best in city traffic, because “the flywheel's stored energy is sufficient to power the car for short periods,” and this allows the engine to be turned off for around half of the entire driving time. It is a system specifically designed to work at its most efficient in stop-start traffic.

[youtube]http://www.youtube.com/watch?v=VowB4MGQqQQ[/youtube]

http://www.carscoops.com/2013/04/volvo- ... -that.html

[Cam]

Uh oh, F1 tech relevancy in road cars. The sky is falling.........

nice find BTW.

[Richard]

Unfortunately it is not F1 relevant, flywheel technology was rejected by F1. The rules prevent experimentation, so we'll always have more innovation in the more liberal environment of road car technology.

[Cam]

But the term 'kers' is relevant though. The underlying tech may not be F1 specific, but nowhere else is that term more known. Certainly Volvo would play on that.

[Richard]

It's sad if the only F1 relevance is in the name. Thinking about it, KERS is a much more appropriate name for this because it is storing kinetic energy close to the point of application (ie wheel/axle). That's in contrast to F1 converting kinetic to electrical storage from the wrong end of the ICE power train.

[rjsa]

It's sad if the only F1 relevance is in the name. Thinking about it, KERS is a much more appropriate name for this because it is storing kinetic energy close to the point of application (ie wheel/axle). That's in contrast to F1 converting kinetic to electrical storage from the wrong end of the ICE power train.

We should not forget that Volvo never touched F1...

[tok-tokkie]

Obviously a practical and appropriate design. Trouble is the copy writers are then given the job of spinning it to the 'unwashed' public so we get:

The Swedes claim the system works best in city traffic, because “the flywheel's stored energy is sufficient to power the car for short periods,” and this allows the engine to be turned off for around half of the entire driving time. It is a system specifically designed to work at its most efficient in stop-start traffic.

Which approaches absolute rubbish = perpetual motion, so to speak. 50% off + 50% on = 0.

[Paul]

Unless you use engine to spin the flywheel as well as drive the wheels when it's working, then it's plausible.

[Richard]

Half the driving time could include the time when stationary. So the equation could be as simple as 45% stationary, 5% flywheel, 50% ICE.

[Paul]

True, but in those conditions a simple stop-start system would match the 50%. Bottom line, your mileage will vary.

[countersteer]

I've done a bit of google research on this and still can't get a clear understanding of what exactly they are doing.

Is this an application of the Williams hybrid system now in use by Porsche in their sportscars where an MGU harvests/returns energy to the drivetrain while connected to the flywheel with its own MGU to facilitate storage/harvest of energy from the flywheel?

Or.. are they mechanically connecting the drivetrain to the flywheel through use of clutches and a CVT which is a whole new level of mechanical complexity?

Thanks for any input...

[Pup]

Appears to be entirely mechanical. From the video below, this looks like a completely separate from the rest of the drivetrain; i.e., the engine drives the front wheels and the flywheel the rear. In one sense that simplifies the whole thing, but at the cost of two transmissions.

[Pierce89]

Very similar to the Flybrid CFT, but the flybrid uses a series of cllutches rather than a CVT.

[Edis]

Very similar to the Flybrid CFT, but the flybrid uses a series of cllutches rather than a CVT.

It IS the Flybrid system. Look at the Picture and you will notice their "f" logo on the side of the unit.

Only the second generation F1 version use clutches, other versions use a torotrak/Xtrac CVT.

[xpensive]

It's sad if the only F1 relevance is in the name. Thinking about it, KERS is a much more appropriate name for this because it is storing kinetic energy close to the point of application (ie wheel/axle). That's in contrast to F1 converting kinetic to electrical storage from the wrong end of the ICE power train.

Truer words never spoken, it would be most interesting to learn about the total efficiency of F1 KERS, probably less than 50%.

Energy is going from the wheels thru the entire drivetrain, spinning a generator to convert mechanical energy to electrical, charging a battery, then discharging electrical energy from battery to a motor to convert back to mechanical energy and finally sending the remains thru the drivetrain to the wheels. Pathetic really.