Newsgroups: sci.energy
Subject: Re: Flywheel batteries as EV power source
From: oberland@vax.sonoma.edu
Date: 17 Dec 92 06:28:54 -0800
Organization: Sonoma State University

In article <1992Dec17.011649.987@cmkrnl.com>, jeh@cmkrnl.com writes:
> In article <1992Dec16.192456.6261@news.cs.brandeis.edu>,
>  andyh@chaos.cs.brandeis.edu (Andrew J. Huang) writes:
>> <I have to admit an emotional response to this since I think that
>> flywheels have tremendous potential.>
> 
> The flywheel is a great way to store mechanical energy.  However I'm not
> certain about the means for using it.  Somehow the energy must be gotten 
> outside of the container.  Mechanical couplings are probably out -- too much
> friction.  I suspect that there could be magnets on the flywheel shaft which
> would energize a stator coil placed around the outside of the flywheel container
> (tolerances would have to be really tight here).  Or perhaps the entire 
> alternator could be put inside the container.  
> 
> Then we come to electric motors to drive the wheels.  Electric motors have
> wonderful torque/speed characteristics for vehicles (they generate maximum
> torque just before stall speed, which may make transmissions and clutches
> unnecessary) but lousy power density -- look at the size of a 1-hp. electric
> motor sometime and tell me how big a motor would have to be to accelerate a
> car fast enough to keep up with gasoline-powered ones.  
> 
> Maybe hydraulics?  Hydraulic "motors" have the same great torque as electrics
> and can be incredibly small for a given power level.  The hydraulic pump
> could be inside the flywheel housing; there could be a bypass valve which would
> be cut in for "idling".  You'd lose something to the friction of the fluid in
> the piping but not much.  
> 
> Maybe the greatest thing about the flywheel is that, if you design the system
> right, you brake by turning the system back on itself and pumping energy back
> into the flywheel.  (This can be made to work for battery-powered electric cars
> too, but it works best with the flywheel, since the flywheel can absorb energy
> at just about any rate you can throw at it, while there are strict limits on
> how fast you can pump watt-seconds into a battery.)  This gets rid of the
> second biggest waster of energy in a car (after the thermal losses in the
> engine) -- the brakes! 

If *I* were to build or buy ANY vehicle I could choose, and wished to get good
performance and good(enough) range and cost, I'd go for a steam-powered
vehicle as proposed earlier on this group.  OHHHHHH a 20-30 second startup!
damn good specs, IMO, and a LOT cheaper to make than an EV.  I perticularly
like the piston design, as it can be used to slow you down on long hills.
-I thought of this a bit back:WHAT happens in an EV during a 5-10 mile down-
hill grade?  MOre importantly, without any engine drag and having it maximized
for speed and low resistance to wind, WHAT happens to your brakes?

I realllllllly would not know what to do if I could not down-shift!

I think a quick-boiler design(maybe, MAYBE run off of batteries?) would offer
a lot of plusses, and little in the way of tradeoff.  My optimal "design in my
mind" would be fuel to get it hot, and switch over to batteries for maintaining
the heat needed.  OR possibly use both battery and fuel to get the start-up
time to less than 30 sec.  Either way, so little pollution that it is probably
less than an EV, and no real size, price, and utility tradeoffs.

ANyone have any info on what it ould cost for such a vehicle(home-made vs
mass produced)?  I bet it would cost little more than current IC designs.

Joe





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