You have a valid argument, but it isn't in the same context as what dinosaur fan and Dino are saying. Sure when you compare the various fuels in the exact same engine you are going to have big discrepencies in mileage and power output. However, when you optimize the engine for the fuel it is burning, E85 can match and exceed gasoline in mileage and power output, due to the differences in combustion and thermal efficiencies, even though it has a lower heat energy. Methanol has even lower stored heat energy than Ethanol, making it a worse choice. Ethanol can be made from fermenting just about anything, not just corn. I agree that most likely alcohol production can't keep up with demand, but it sure can lessen the demand for crude oil.

 

One of the stations here converted a pump to E85.

Three of the things mentioned in the article were that A) stainless steel tanks and lines are required, B) it's not economically feasible to convert a gasoline-only engine to E85 or multifuel, and C) vehicles running E85 can typically expect 10-20% fewer miles per gallon.

I really wouldn't expect something like that here, in the middle of the corn-belt, if there wasn't a kernel (sorry!) of truth.


I don't know about E85 prices elsewhere, but even a 5% decrease in fuel efficiency is going to raise the customer's cost-per-mile.

 

Not really because to make the comparison valid, you need to optimize all engines for the fuels being used plus when you boost CR a lot on a alchol engine to help improve its efficency (though it will never match a gas motor because there simply is not enougn BTU's in fuel) you will also turn them into very high NOx generators like diesels are and detroit is scrambling to meet 08 NOX emission reductions for diesels in 08

 

NOx results from high combustion temperatures. Keep in mind that ethanol has a lower flame temperature than gasoline, which will actually reduce NOx emissions. So maybe with the higher compression ratio, there is not really any net gain. Alcohol also emits fewer HC emissions.

You keep saying that it will never happen, but two other folks have already presented facts where Ethanol has surpassed gasoline fuel economy.

You are basing your comparison on the same engine, with the same compression ratio, running all three fuels. andI said the engines must be optimized. You are also missing the point of thermal efficiencies. No one here is arguing the actual heating values of the fuels. Even though ethanol has a lower heating value than does gasoline, if more of that energy can be extracted and converted to mechanical work, it is possible to equal and surpass the fuel economy and power output of a gasoline engine.

Gasoline and gasoline engines have had roughly 100 years of development to get to where we are today. I'm positive that with the same amount of research and development on ethanol and ethanol engines, the fuel economy and power output (and emissions) can improve from where they are today.

Ref. pp. 171-175 Engineering Fundamentals of the Internal Combustion Engine 2nd Ed. by Willard W. Pulkrabek