Flywheel Hybrid Technology

[Fledermaus]

I extend the middle digit of my left-hand; tweak a tiny titanium paddle; release the frustration of 160 horses and transform a ‘normal’ 911 racing car into something quite extraordinary. This is the Porsche 911GT3 R Hybrid, a million dollar test bed that could yet prove one of the most significant sports cars of recent years.

"A flywheel solution has a key advantage compared with a battery," says Hartmut Kristen, head of Porsche motorsport. "With a battery-based solution, you can't collect all the energy because to do so would overpower and destroy the batteries. But with a flywheel, that problem ceases to exist." Fully charged, the system offers 6-8 seconds of boost.

http://www.classicandperformancecar.com/news/octanenews/254521/first_drive_porsche_911gt3_r_hybrid.html

http://www.youtube.com/watch?v=4PcIt0FPvWQ

[Schema Thing]

1. I just love the idea of using flywheels to store energy.

I know it's not "free" energy, but somehow it just feels free anyway :D

[wtmusic]

2. Seems like cornering would get pretty wacky

from the precession of a gyro like that. On F1 racecourses the corners aren't that sharp, but on a city street the understeer might pull you right into the 7-Eleven across the street...unintentionally. :scared:

[NYC_SKP]

4. True, but the car would be harder to flip.

If I'm not mistaken.

:hi:

[OnlinePoker]

6. Would it make a difference if the flywheel was perpendicular to the car's direction of travel?

Or would that make it even more difficult to steer? Played with gyro's as a kid, but don't really know the physics behind them.

[Ready4Change]

8. Just what I was thinking.

The picture shows the axis of rotation as horizontal. I'd think that would resist efforts to change the direction of the car (yaw). But if the axis was vertical, that would fight efforts to roll or pitch the car.

But that effect of flywheels confuses me. I'm thinking that through 'precession' that an attempt to roll the car would become an attempt to pitch it, and pitch would become roll? Or do I have that wrong?

I also wonder how strong this effect is, compared with the extra torque being transferred to the flywheel and compared against the total vehicle mass. Too many variables I don't have a reference for.

[wtmusic]

9. It does seem that if the axis was vertical

it could be beneficial to the car's handling, as long as it's mounted close to the car's center of gravity. Possibly there are mechanical reasons why that's impractical.

Precession will resist any attempt to tilt the axis of the gyro in either of the two perpendicular dimensions.

If you wanted to get really fancy you could do trade the mechanical linkage for an electric motor/flywheel assembly in a gimbal, at what would be a significant penalty in weight.

[Dead_Parrot]

13. Although then, sudden braking or acceleration would get interesting

The car will try and spin in the other direction to the flywheel acceleration - think of a helicopter with a broken tail rotor. Takes 'steering with the throttle' to a whole new level...

[phantom power]

10. I saw a demo of a fly-wheel based sportscar at my college back in 1990

That guy used a pair of counter-rotating flywheels to zero out the gyroscopic force.

[wtmusic]

11. Counter-rotating flywheels using the same axis

zero out any effects of torque during charge or discharge, but double the precessional (gyroscopic) effect.

[txlibdem]

3. Electric cars and trucks are needed now... today!

But the batteries don't like to have high current drained out of them rapidly - as would happen during acceleration up to freeway speeds. Batteries also do not like to have all the regenerative braking energy pushed back into them that fast. So what happens? The battery will do what you ask but not at high efficiency and repeating that process over and over for years can reduce the usable capacity of the battery. Adding flywheel energy storage for use when accelerating or braking via regenerative brakes is a very good idea.

AFStrinity has a similar hybrid system as the 911 flywheel except it uses supercapacitors to store the energy involved in braking and accelerating.

For a battery-electric car with one of these systems built into it, the battery can be smaller (fewer kWh) and therefore cheaper.

[Fledermaus]

5. They would make an almost ideal replacement for super capacitors.

New fly wheels use a carbon fiber disk or ring inside a can. All of the air is removed to reduce drag. If the fly wheel breaks, for what ever reason, the energy is contained in the can. The carbon absorbs the energy and turns into dust.

[txlibdem]

7. Replace

I don't see why flywheels would have to replace supercapacitors when they both do the same thing quite well. Let the market decide which will win.

Supercaps may have the edge where price is concerned. Flywheels may be more scalable for use in big rigs or construction equipment.

[Fledermaus]

12. Yes, there are many types of Kenetic Energy Recovery Systems compeating in fourmula 1 now

Ferrari F2009 KERS K.E.R.S. for dummies
http://www.youtube.com/watch?v=R-A6ZcenX7s

F1 KERS system 2009
http://www.youtube.com/watch?v=xAvexjr2ax0&NR=1&feature=fvwp

The new Formula 1 Season 2009
http://www.youtube.com/watch?v=puG3qpWYR5o&feature=channel

[muriel_volestrangler]

14. FWIW, all teams dropped KERS for 2010

I think only a couple of teams used it in races in 2009, and I think one may have dropped it mid-season. The acceleration advantages were outweighed, literally, by the extra mass of the system. And in 2010, when there is no refuelling allowed, and most if not all teams don't carry enough fuel at the start to race at full power for the whole race, no-one is using it, so it would not seem to offer any significant advantage for fuel economy for those racing cars either.

I think the ones used were all-electric, rather than flywheel.

[Fledermaus]

15. Perhaps the most wicked hybrid ever, the 918 Spyder concept will become a roadgoing reality.

The 918 Spyder is a performance hybrid with four distinct driving modes and an extra, KERS-type overboost feature like that found on some F1 cars in 2009. It is motivated by various combinations of its 500-plus-hp, 3.4-liter V-8 (derived from the RS Spyder LMP2 car) and three lithium-ion-powered electric motors—two on the front axle and one integrated into the transmission—that make a total of 218 hp. Interestingly, the 918 Spyder can function as both a parallel or a series hybrid, as the electric front axle can propel the car on its own, or in conjunction with the engine. In its thriftiest mode, Porsche states a European-cycle figure of 78 mpg. In race mode, expect a top speed in the neighborhood of 200 mph and a Carrera GT–beating Nürburgring lap time of 7:30.

http://www.caranddriver.com/news/car/10q3/porsche_918_spyder_concept_confirmed_for_production-car_news