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. .
They only need to weigh less than batteries. Over a third of a Tesla Roadster's weight is batteries.
Interesting articles. I think that “Booze in a Bag” has a real future.
Some good back-of-the-cereal-box-reading here: http://flywheel.esmartbiz.com/facts.htm
I remember those! I had the Black Jack in blue chrome.
I had the Black Jack!
And how will the extra energy needed to spin the flywheel and carry its weight be offset by transferring its reduced spin to power the wheels? Sounds like perpetual motion to me.
The E-2A Navy airplane carried a drum data storage drive. It was big and heavy and turned at a high speed. When they test flew it the airplane wouldn’t turn because of the drum’s gyroscopic rigidity in space.
It’s not a ‘new’ technology. It has been used in the past. Switzerland used it to power trolleys and it has even been used in a Formula one racing engine. The process works and has worked. It seems just right for hybrid cars.........
They would still need to mount it like a gyro.
On rotating axis.
Those things will act like C4 in an accident.
They’re running them in F-1 and those boys wreck pretty hard.
Think of an electric DC motor, you have the rotor and the stator around it. Make the rotor flat and wide, and make the stator all-enclosing, not even a driveshaft protrudes. Then suck all the air out of the stator.
Apply electricity to spin that sucker up. Then remember that a DC motor is a DC generator, just depends on whether you’re adding electricity to create torque in the rotor, or using the rotor’s existing torque to create electricity.
People used to worry about the idea of driving a car that carries ten gallons of a highly flammable liquid.
The torque issues are real, no matter how the flywheel is oriented.
But equal counter-rotating wheels will address the issue fully, given a sturdy frame to connect them.
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..
Accompanied by the repeal of the laws of physics that govern gyroscopes.
Oh, wait... it sounds sorta like that already (not as much cam lope). They did do a good job of making it read the engine speed through the cigarette lighter socket, though.
Just the newest version of this concept, I guess.
No wonder I am NOT an engineer in the field of fluid dynamics. Thanks for the reality check.
Since F-1 cars turn both left and right, I assume they have dealt with your concern.
http://www.racecar-engineering.com/articles/f1/flywheel-hybrid-systems-kers/
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