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

1. Use the oil simply as it is-- typically 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 gas;

3. Convert it to biodiesel.

The very first two techniques sound most convenient, but, as so typically in life, it's not quite that basic.

1. Mixing it

Grease is much more viscous (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 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 the majority of, but still unclean enough, lots of 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 use numerous mixes, ranging from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals simply utilize it that way, start up and go, without pre-heating it (which makes veg-oil much thinner), and even utilize pure grease without pre-heating it, which would make it much thinner.

You may get away with it with an older Mercedes 5-cylinder IDI diesel, which is an extremely hard and tolerant motor-- it will not like it but you probably will not kill it. Otherwise, it's not sensible.

To do it effectively you'll require what totals up 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 gas are "speculative at finest", little or absolutely nothing is learnt about their effects on the combustion characteristics of the fuel or their long-term results on the engine.

Higher viscosity is not the only problem with utilizing grease as fuel. Veg-oil has different chemical residential or commercial properties and combustion qualities from the petroleum diesel fuel for which diesel motor and their fuel systems are developed.

Diesel engines are modern machines with very exact fuel requirements, particularly the more modern-day, cleaner-burning diesels (see The TDI-SVO controversy).

They're hard but they'll only take a lot abuse. There's no guarantee of it, however utilizing a mix of approximately 20% veg-oil of excellent quality is said to be safe enough for older diesels, particularly in summer.

Otherwise using veg-oil fuel needs either an expert SVO service or biodiesel. Mixes and blends are generally a poor compromise. But blends do have an advantage in winter.

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