According to the Advanced Combustion Research for Energy from Vegetable Oils (ACREVO) group, “Atomisation tests showed that at 150°C the performance of the rapeseed oil are comparable with that of diesel oil…… It has been established that an addition of 9% of ethyl alcohol (95%) brings a great benefit regarding the pre-heating oil temperature. In fact, the presence of alcohol allows a reduction in the inlet oil temperature from 150°c to 80°c…… the combustion of the emulsion produces less soot and, at the exhaust, the amount is almost one half less than that produced by the combustion of (high temperature) rapeseed oil.
Generally all measured operating characteristics power, torque, fuel consumption and efficiency prove, that when using these novel fuels there are only slight power and consumption disadvantages in comparison to diesel fuel.”
(Source: http://www.biomatnet.org/secure/Fair/F484.htm)
I assume that the alcohol would thin the oil and raise the octane levels, and according to the above mentioned document, make the fluid behave more like diesel fuel at achievable temperatures.
I have not seen the addition of alcohol referenced by any of the SVO suppliers or on web forums, but this research document convinced me to experiment with adding up to 10% methanol to my oil when convenient to do so. I have had some issues with the blending, and am not confident enough with the process to be advising on how to go about it. The blending of alcohol with the vegetable oil is highly experimental.