Quote:
Originally Posted by oil pan 4
If prevaporization of fuel works so well then why don't propane engines offer a substantial increase in fuel economy over gas engines on a BTU/mile basis?
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Here is a masters level thesis on simulated engine performance with comparison to test data.
http://repository.tamu.edu/bitstream...EEN-Pathak.pdf
The brake specific fuel consumption (BSFC) is only 3-5% better than the gasoline analog (iso-octane). Thus, it can be concluded that a gas state engine has only a small advantage over liquid state engine.
However, this does not take into account the change in other variable conditions that gasoline evaporation systems add to the combustion environment. People make reference to the old "evaporator carbs" and claim huge mileage increases. I have constructed "vapor carbs" in the past and measured only a 50% improvement in fuel economy at cruise on older carburated truck engines. A modern application on modern engines yields a 30% efficiency increase. Here is a link to a legitimate company effort.
Vapor Fuel Technologies | Home to the VFT Vapor System