Påtal om sekelskiftet,
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SPECIAL ENGINES FOR ALCOHOL.
By using alcohol in an alcohol engine with a high degree of compression
(about 180 pounds per square inch above atmospheric
pressure much higher than can be used for gasoline on account
of preignition from the high temperatures produced by compression),
the fuel-consumption rate in gallons per horsepower per hour can be
reduced to practically the same as the rate of consumption of gasoline
for a gasoline engine of the same size and speed. The indications
are that this possible 1 to 1 fuel-consumption ratio by volume for
gasoline and alcohol engines will hold true for any size or speed,
if the cylinder dimensions and revolutions per minute of the two
engines are the same.
When alcohol is used in a gasoline engine with the maximum
degree of compression for gasoline, the available horsepower of the
engine is increased about 10 per cent. An alcohol engine with the
maximum degree of compression for alcohol will have an available
horsepower 30 per cent greater than a gasoline engine of the same
cylinder size, stroke, and speed. Owing to the higher explosion
pressures, however, an alcohol engine should be built heavier than
a gasoline engine, but the weight per horsepower nray be less.
- COMMERCIAL DEDUCTIONS FROM COMPARISONS OF GASOLINE AND ALCOHOL TESTS ON INTERNAL-COMBUSTION ENGINES BY ROBERT M. STRONG.
1909. Mer direktrelaterat till dieselmotorer och etanol (och något nyare studie
):
http://www.mncorn.org/sites/mncorn.org/ ... Engine.pdfCitat:
It was discovered that as predicted hydrogen injection allowed direct use of 100% ethanol as a Diesel fuel under moderate compression ratio and intake pressure conditions.
This suggest that it will be possible to run a Diesel engine with ethanol as the sole fuel if
a suitable low cost system for onboard conversion of a small fraction of the ethanol into hydrogen rich gases can be developed. The fumigation work revealed that ethanol can be used to offset 40% of Diesel fuel use with only slight losses in thermal efficiency. Ethanol fumigation significantly reduced particle emission, but increased hydrocarbon emissions, and under some conditions NOx emissions.
Finns en del att läsa i den studien om tidigare försök med olika metoder också, men det verkar som det låga Cetan-talet (istället för oktan som är relevant i bensin-motorer) för etanol ställer till med en del problem.
Från wiki:
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Bränslen med högt cetantal, till exempel ogrenade kolväten, har låga oktantal och bränslen med höga oktantal, till exempel starkt grenade kolväten, har låga cetantal
Specifikt för våra bredgrader står det även detta i studien:
Citat:
Another issue limiting the use of ethanol as a diesel fuel relates to difficulty in autoignition required by CI engines. Alcohol autoignition and ignition improvers have been investigated (Schaefer, et al., 1981; Lee, et al., 1993; Bollentin, et al., 1996). Nearly pure ethanol (E95) is used in Scania engines to power buses in Stockholm, Sweden, but an expensive ignition improver and extremely high compression ratios (~ 28:1) are required to facilitate operation. Such high compression ratios reduce engine efficiency, thus reducing to some extent, the efficiency advantage that CI engines have over SI engines.