At 07:17 PM 10/26/00 -0400, you wrote:
>I hope someone can tell me:
>
>1) Can alcohol with non-corrosive additives be the fuel for regular,
>unmodified internal combustion engines?
>
>2) What would be the comparative cost of alcohol versus gasoline at the pump,
>disregarding the cost of pump modification?
>
>3) Would an alcohol-fueled combustion engine have any pollutant exhaust?
>
>4) What other room termperature liquid fuel replacements to gasoline exist?
>
>Ross
Alcohol (methanol and ethanol) is used in race engines. It runs great, but
is can be difficult to start in cold weather. "Gasohol" is a mix of
gasoline and alcohol - up to 10% normally, ethanol. Methanol, I believe, is
more corrosive than ethanol, and both alcohols will make certain plastic
and rubber parts in older cars deteriorate. To use it as a motor fuel would
require some additives to improve starting and minimize corrosion, just
like additives in gasoline tailor octane rating and help prevent formation
of deposits in the fuel system.
Methanol can be made from methane, either fossil natural gas or gas from
composting organic matter.
Alcohol made from corn (ethanol) is pushed by the farmers and greenies, but
I do not think it would be cost-competitive with gasoline. Of course,
gasoline is presently price-supported in the US, so any comparisons would
be warped. It does have the advantage of being biomass, so it does not add
to the CO2 burden like fossil fuels. I have heard that the costs of raising
enough corn to produce a gallon of alcohol exceed the value of the alcohol
as fuel. One item I read had just the fuel burned by the farmer's tractor
being more than the heating value of the alcohol. If this is true, biomass
alcohol is nothing more than another price support for farmers.
Alcohol has less heating value per unit weight than gasoline, so mileage
for a pure alcohol powered vehicle will be less than for gasoline.
Any combustion engine has pollutants in its' exhaust. A well tuned piston
engine with a properly fitted catalyst can be close to "zero" pollution,
but never quite gets there. Alcohol burns somewhat cleaner than gasoline,
so that should reduce unburned hydrocarbons. Gas turbines and external
combustion (steam) engines are less polluting than piston engines since
they are continuous combustion, which can be more easily regulated. Any
power source that uses a hydrocarbon, including fuel cells, will emit CO2,
and the greenies want that classed as a pollutant, too. Only pure hydrogen
(at present) burned so as not to produce any oxides of nitrogen, can be
considered totally pollution free. Since high efficiency engines want as
high an input temperature as possible, NOx emissions are always a
consideration.
Any flammable liquid that can be fed through a fuel injector can be burned
in an internal combustion engine. Diesel engines have been modified to run
on corn oil, used frying oil, liquefied coal, etc. Whether one wants to,
given the pollution, and inherent inefficiency of an IC engine, is another
thing. I think advances in fuel cell technology will soon make fuel cells
more attractive than IC engines for many automotive applications.
I don't think we will see an end to IC engines anytime soon, as they are
just too simple and relatively cost effective in too many applications.
Chuck Kuecker
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