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Microcap & Penny Stocks : BAAT - world records for electric vehicles with zinc-air
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To: dwight martin who wrote (1910)2/17/1998 11:41:00 AM
From: shashyazhi  Read Replies (1) of 6464
 
My main objection to hybrid diesel electric cars has always
been the simple formula involved in efficiency of energy
conversion. Let us say that, at best, the chemical to mechanical
energy conversion of the internal combustion engine is 25%.
And some 15% is lost in the gear train. You are down to 21.25%
efficiency with the standard transmission arrangement. But what
if you use your 25% efficient IC engine to drive a 50% efficient
DC generator which, in turn sends electricity to a 50% efficient
DC motor to drive the wheels? Do the math, and you will see
that the efficiency is down to 6.25%, disregarding the probability
that you have a battery in the system storing some of that power
and returning it at 50%. If you know what the efficiency factors
of AC energy conversion you can factor them into the equation.
I don't happen to remember what the efficiency of 3 phase
alternators is, but it is higher than 50%. If it was 75% you would
still only come out with 14% efficiency using the IC engine to drive an
AC generator to drive an AC motor. I have been reading books
like "Engineer's Dreams" and magazines like Popular Science
and Popular Mechanics since I was a little kid, but none of the
dreamers has come up with any solution as elegant and efficient
as the IC engine with a mechanical transmission. Steam? Try to
fire up a boiler and build pressure before work every morning.
Gas turbines? They cannot be produced cost effectively and
still have a high enough compression ratio to realize their efficiency
potential. Wankels? Hmmm. There's an eccentric shaft in there
that suspiciously resembles, dare I say it? A crankshaft! Storing
energy in a capacitor? Too dangerous to the backyard mechanic.
Storing energy in a flywheel? How do you retrieve it efficiently?
Do you use a friction clutch, or does it drive a 75% efficient
AC generator driving a 75% efficient AC motor. Or is the flywheel
actually the rotor in some sort of AC motor? Maybe there is only
one stage of intermediate energy conversion? 25% IC efficiency
time 75% still equals only 18.75% efficiency. You just cannot beat
the efficiency of that car you drive today. But you can hope to
get a little better fuel economy, which is not the same thing as
efficiency. The mechanical transmission is the key to the best
efficiency by keeping the engine rpm in the most economical range.
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