Flying by:A computer model of Volvo's flywheel, with an outer section cut away. Credit: Volvo
Posted on 07/13/2011 12:44:52 PM PDT by Red Badger
An old technology could make hybrid cars much cheaper.
The automakers Volvo and Jaguar are testing the possibility of using flywheels instead of batteries in hybrid electric vehicles to aid acceleration and help engines operate more efficiently. The devices could reduce fuel consumption by 20 percent and would cost a third as much as batteries. Volvo will begin road-testing a car with the technology this fall.
In a flywheel system, energy from the wheels is used to spin a flywheel at high speeds. The flywheel continues spinning, storing energy until that motion can be transferred back to the wheels via a transmission. The idea isn't new, but it's hard to make flywheels efficient—a lot of energy can be lost to friction. In 1982, for example, GM engineered a flywheel system that was intended for its 1985 vehicles, but they canceled the project after discovering that the fuel efficiency improvements were less than half of what they'd expected. Advances in the technology now have automakers taking a second look. "Industry has gone from being skeptical to thinking it can be done, but there are enormous challenges," says Derek Crabb, vice president of powertrain engineering for Volvo.
Engineers who design Formula 1 race cars have tried to overcome the challenges of a flywheel system by using composite materials to save weight. To reduce friction, they've sealed the flywheels inside a vacuum chamber. In translating that system to passenger cars, automakers face the problem of how to maintain the vacuum, since the seals that connect the flywheel to a transmission aren't perfect.
This is fine in racing, where the system only has to last a couple of hours at a time, and can be overhauled by team mechanics. Consumer cars using a similar design would need a system to maintain the vacuum with pumps and valves—and that adds complexity and cost. In another approach, from the U.K. engineering firm Ricardo, the mechanical connection between the flywheel and the transmission is severed. Instead, energy from the flywheel is transferred to a transmission via magnets arranged around the circumference of the flywheel and in a ring outside the flywheel housing. By varying the ratio of the magnets in the flywheel to those arranged around it, it's possible to make the flywheel spin six times faster than the ring around it, which simplifies the transmission of energy.
One advantage of flywheel systems over batteries is their compact size. "Most hybrids with batteries provide a 15- to 25-kilowatt boost of power. The flywheel can deliver 60 kilowatts in a way smaller package," says Andrew Atkins, chief engineer of technology at Ricardo. The trade-off is that flywheels can't supply energy for very long. .
Crabb says Volvo hasn't decided if it will use a system such as Ricardo's or something else to maintain the vacuum. Many challenges remain in bringing a flywheel hybrid to market. For instance, automakers will have to ensure that the systems can be durable, and can be manufactured on a large scale, he says. Flywheels will also have to compete with batteries and other electrical storage devices such as ultracapacitors, which are getting more powerful and less expensive. .
Flying by:A computer model of Volvo's flywheel, with an outer section cut away. Credit: Volvo
Automobile Tech Ping!.............
And will the torque make it easy to turn right but hard to turn left?
Behold! All thing old are new again!................
Not If it’s horizontal............
Seems like for production automobiles, there would be a bigger problem with soft Chinese bearings than with drag from the *air*.
I recall talk of this back in the 90s for Tanks. One of the issues was that when the tank is moving, It can't turn or it could potentially flip over. That's a lot of energy.
Check this out: Formula 1 ‘Flybrid’ racing engine...........
http://www.flybridsystems.com/F1System.html
Ah...the crux of the problem!!!! Awful hard to create momentum without mass - therefore weight...
I wonder if a “normally sealed unit” - as “sealed” as most ordinary “sealed” units are in cars today, filled with some very slippery but dense liquid (to reduce the flywheel’s friction) and with the flywheel suspended in it (suspended in the liquid), would be better (”almost” as efficient and more economical) than a pure vacuum.
For heat (the sealed-in-fluid may obtain heat in the operation of the flywheel), engineer the casing of the unit to “exchange” the heat out of the unit in some way, either simply, because it - the casing is exposed to air somehow, or some more esoteric solution.
It might even come equipped with a backup pull-starter:
Someone will be dead, and Volvo will just say "Whoops".
...but your car will flip on it’s driving fast over a hill...jk.
Simple, make the flywheel essentially the inner part of an electric generator. Add or bleed energy using electromagnets, not a mechanical transmission.
LOL - So just be careful going over hilltops eh?
SIDE...but your car will flip on it’s SIDE driving fast over a hill...jk.
DOH
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