[extropy-chat] 12000 miles per gallon (equiv) !!

[Mike Lorrey]

--- BillK <pharos at gmail.com> wrote:

> 
> "Our goal is to build a car powered by a fuel cell that uses as
> little fuel as possible."
> 
> So, yes, it is very light, yes, it is very streamlined, and yes, it
> just keeps going round and round the track. They are not building
> your average commuter vehicle. :)

The prof claimed they used technologies which would be road applicable.
I fail to see how a 30 kg bike has much that applies to a road worthy
car.

> But they did drive off from a standing start as specified in the
> Shell Eco-marathon rules.
> And achieved a world record 12 thousand mpg equivalent.
> See <http://www.shelleco-marathon.com/index.htm>
> 
> As I understand it, fuel economy does not apply to solar-power cars
> as they do not use any fuel at all. Infinite mpg! 

Solar car teams do calculate equivilancy based on watt-hours conversion
to horsepower and thence to average fuel economy per horsepower.

> Regenerative braking on downhills also helps to charge the batteries.
> 
> The PAC car does not use any solar cells.
> "Whereas most of the other fuel economy vehicles burn fuel in an ICE
> (Internal Combustion Engine), PAC-Car II uses a fuel cell to convert
> hydrogen into electricity to power its electric motors. The main
> advantages are greater efficiency, much more silent operation and
> most importantly, zero emission with pure water as the only by-
> product."

Technically speaking, a fuel cell peak effiency is at best 99%
conversion of chemical bond energy, minus efficiency of the electric
hub motors, any battery storage, voltage treatment, as well as rolling
and aerodynamic resistance. With this vehicle, efficiency likely
remains in the high 80%'s to low 90%'s.

Conversely, an ICE vehicle typically has an on the road efficiency of
about 15% or less. Assuming 30 mpg for such a vehicle, the best it
could attain at, say, 95% efficiency would be 195 mpg. Any gains in
efficiency beyond 100%, which would be above 200 mpg, must come from
reductions in weight, which means potentially compromising passenger
safety, or in vehicle size, i.e. aerodynamic cross section and surface
area, which impacts passenger and cargo capacity.

A particle of zero size can travel with infinite efficiency, but it
can't carry much, can it?

Mike Lorrey
Vice-Chair, 2nd District, Libertarian Party of NH
"Necessity is the plea for every infringement of human freedom.
It is the argument of tyrants; it is the creed of slaves."
                                      -William Pitt (1759-1806) 
Blog: http://intlib.blogspot.com


		
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