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

1. Use the oil just as it is-- usually called SVO fuel (straight veggie oil);

2. Mix it with kerosene (paraffin) or petroleum diesel fuel, or with biodiesel, or blend it with a solvent, or with gasoline;

3. Convert it to biodiesel.

The first 2 approaches sound most convenient, but, as so frequently in life, it's not rather that simple.

1. Mixing it

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

If you're mixing veg-oil with petroleum diesel or kerosene (very same as # 1 diesel) you're still utilizing fossilfuel-- cleaner than many, however still unclean enough, numerous would say. Still, for every single gallon of

veggie oil you use, that's one gallon of fossil-fuel conserved, and that much less climate-changing carbon in the environment.

People utilize different mixes, ranging from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals simply utilize it that way, launch and go, without pre-heating it (that makes veg-oil much thinner), or even utilize 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 very tough and tolerant motor-- it will not like it however you probably will not eliminate it. Otherwise, it's not sensible.

To do it effectively you'll need what amounts to an SVO system with fuel pre-heating anyway, preferably using pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no requirement for the mixes.

Blends with different solvents and/or with unleaded gas are "experimental at best", little or nothing is learnt about their effects on the combustion characteristics of the fuel or their long-lasting impacts on the engine.

Higher viscosity is not the only problem with using grease as fuel. Veg-oil has different chemical homes and combustion qualities from the petroleum diesel fuel for which diesel motor and their fuel systems are designed.

Diesel motor are makers with very exact fuel requirements, specifically the more modern, cleaner-burning diesels (see The TDI-SVO debate).

They're hard however they'll only take so much abuse. There's no guarantee of it, but using a blend of up to 20% veg-oil of great quality is said to be safe enough for older diesels, especially in summertime.

Otherwise using veg-oil fuel needs either a professional SVO service or biodiesel. Mixes and blends are typically a bad compromise. But mixes do have an advantage in cold weather.

Similar to biodiesel, some kerosene or winterised petro-diesel fuel mixed with straight vegetable oil lowers the temperature level at which it starts to gel. (See Using biodiesel in winter season) More about fuel blending and blends.