There are at least 3 ways to run a diesel engine on biofuel using vegetable oils, animal fats or both. All three are utilized with both fresh and used oils.

1. Use the oil simply as it is-- usually called SVO fuel (straight vegetable 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 methods sound simplest, but, as so frequently in life, it's not quite that easy.

1. Mixing it

Grease is far more thick (thicker) than either petro-diesel or biodiesel. The purpose of blending it or mixing it with other fuels is to lower the viscosity to make it thinner so that it streams more freely through the fuel system into the combustion chamber.

If you're blending veg-oil with petroleum diesel or kerosene (very same as # 1 diesel) you're still using fossilfuel-- cleaner than the majority of, but still not tidy enough, lots of would say. Still, for each gallon of

grease you utilize, that's one gallon of fossil-fuel saved, which much less climate-changing carbon in the atmosphere.

People use numerous blends, ranging from 10% vegetable oil and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some individuals simply use it that method, start up and go, without pre-heating it (which makes veg-oil much thinner), or perhaps use pure grease 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 however you most likely won't kill it. Otherwise, it's not wise.

To do it correctly you'll need 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 requirement for the blends.

Blends with different solvents and/or with unleaded fuel are "experimental at best", little or nothing is understood about their effects on the combustion attributes of the fuel or their long-term results on the engine.

Higher viscosity is not the only problem with utilizing vegetable oil as fuel. Veg-oil has various chemical properties and combustion characteristics from the petroleum diesel fuel for which diesel engines and their fuel systems are developed.

Diesel motor are modern machines 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 so much abuse. There's no assurance of it, however using a blend of as much as 20% veg-oil of good quality is stated to be safe enough for older diesels, specifically in summer season.

Otherwise utilizing veg-oil fuel requires either a professional SVO service or biodiesel. Mixes and blends are normally a poor compromise. But blends do have a benefit in cold weather.

As with biodiesel, some or winterised petro-diesel fuel blended with straight vegetable oil reduces the temperature level at which it begins to gel. (See Using biodiesel in winter season) More about fuel blending and blends.