There are at least 3 methods to run a diesel motor on
biofuel using vegetable oils, animal fats or both. All 3 are used with both fresh and
secondhand oils.
1. Use the oil just as it is-- generally called SVO fuel (straight veggie oil);
2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with
biodiesel, or mix it with a solvent, or with gasoline;
3. Convert it to
biodiesel.
The very first 2 approaches sound most convenient, but, as so typically in life, it's not quite that simple.
1. Mixing it
Vegetable oil is a lot more thick (thicker) than either petro-diesel or
biodiesel. The function of
blending it or mixing it with other fuels is to decrease the viscosity to make it thinner so that it flows more easily through the fuel system into the combustion chamber.
If you're mixing veg-oil with petroleum diesel or
kerosene (like # 1 diesel) you're still
utilizing fossilfuel-- cleaner than many, but still not tidy enough, many would say. Still, for each gallon of
grease you use, that's one gallon of fossil-fuel saved, which much less climate-changing carbon in the atmosphere.
People use different mixes, varying from 10%
veggie oil and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people just use it that way, begin up and go, without
pre-heating it (that makes veg-oil much thinner), or perhaps use
pure vegetable oil without
pre-heating it, which would make it much thinner.
You might get away with it with an older Mercedes 5
-cylinder IDI diesel, which is a really difficult and tolerant motor-- it will not like it but you most likely will not eliminate it. Otherwise, it's not sensible.
To do it properly you'll require what amounts to an SVO system with fuel pre-heating anyhow, ideally using pure petro-diesel or
biodiesel for starts and stops. (See next.) In which case there's no need for the blends.
Blends with numerous solvents and/or with unleaded gas are "experimental at finest", little or absolutely nothing is learnt about their impacts on the combustion qualities of the fuel or their long-lasting impacts on the engine.
Higher viscosity is not the only issue with utilizing veggie oil as fuel. Veg-oil has various chemical homes and combustion
attributes from the petroleum diesel fuel for which
diesel motor and their fuel systems are
developed.
Diesel motor are modern makers with really exact fuel requirements, especially the more modern, cleaner-burning diesels (see The TDI-SVO controversy).
They are difficult however they'll just take a lot abuse. There's no
warranty of it, but utilizing a mix of approximately 20%
veg-oil of excellent quality is said to be safe enough for older diesels, particularly in summertime.
Otherwise using veg-oil fuel requires either a professional SVO service or
biodiesel. Mixes and blends are normally a bad compromise. But mixes do have an advantage in cold weather condition.
Similar to
biodiesel, some kerosene or winterised petro-diesel fuel mixed with straight grease decreases the temperature level at which it begins to gel. (See Using biodiesel in winter season) More about fuel blending and blends.
