Monty Roberts wrote:

Lynn,

The engines are not exactly fuel cooled. The methanol does help with the
cooling of the valves and chambers, but the real reason it is used is the
high octane rating of methanol and the charge cooling properties that
evaporating this much fuel in the intake has. This produces a much more
dense intake charge than a comparable gas fueled engine. Also there is more
H2O formed in the combustion products, which is a much better working fluid
than air, plus methanol is an oxygen bearing fuel. Fuel cooling (or
inner-cooling, as in our lycosaurus GA engines) suggests excess fuel or very
rich mixtures whereby the excess fuel evaporatively cools the combustion
chamber. The CART guys definitely do not want to do this. They try to
squeeze every mile per gallon possible from the available fuel. Engines can
just plain make more power with methanol for a given displacement regardless
of cooling. The cooling supplied to the valves, piston and chamber by the
cold, dense intake charge is just an advantageous byproduct.

Another good fuel for this is LPG injected as a liquid. This also requires
about twice the fuel flow rate of gasoline, but in addition, it evaporates
and cools the intake charge by taking advantage of the massive latent heat
of vaporization created during the compression and condensation of the gas.
I have always wanted to build a mid engine 3 rotor turbocharged, LPG/nitrous
oxide variable geometry ground effects car. ARRR ARRRR ARRRRRRRRR

This is great for race cars, but horrible for airplanes where we want the
highest energy density fuel possible (more bang per pound therefore better
range). Kerosene is better than gasoline, diesel is better than kerosene,
and I suppose if you could make an engine run on tar, that would be even
better.

Monty

 
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