Quote:
Originally Posted by Flieger
Pure ethanol is atually a very good auto fuel. Ethanol and Methanol powered many GP cars in the era of the Silver Arrows. It is very high octane after all.
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No it is not. It's a very inneficient motor fuel. It has a relatively low BTU count so the energy you get out of a gallon of ethanol is significantly less than that of a gallon of gasoline.
The only reason it is used in racing enginers is that it allows them to run a very high compression ratio which results in higher torque and HP numbers, along with much higher gallons burned per mile.
When efficiency and economy don't matter, ethanol can make more total power per displacement.
But efficiency and economy DO matter.
They matter a great deal. That's why ethanol is a sheety fuel for normal use and gasoline/diesel are so much better.
Gasoline stoiciometric is 14.7 to 1.
That means it take 14.7 pounds of air for every pound of gasoline to reach a lambda of 1 (ideal air/fuel mixture to burn cleanly and efficiently).
Now lets compare that to ethanol, shall we?
Lets pick a mixture, say E85. We're all familiar with that stuff, right?
Stoiciometric for E85 is 9.765 (lambda of 1).
That means it takes 36% MORE E85 than gasoline for the same displacement engine and RPM to stay at an idea A/F ratio.
FUELS DATA
So they start cheating and leaning it out.
Hey, it won't hurt an engine to run lean, will it?
They program those "flex fuel engines" to run lean and lessen the loss of MPG, but leaning it out further reduces power being made whch requires more throttle which further reduces MPG.
For the life of me, I cannot think of many organizations OTHER THAN THE GUBMINT that would be capable of coming up with any idea/program/concept that makes less sense
(tree huggers cough cough)