There are at least three ways to run a diesel engine 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-- 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 gas;

3. Convert it to biodiesel.

The first two approaches sound simplest, however, as so often 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 mixing 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 (like # 1 diesel) you're still utilizing fossilfuel-- cleaner than most, however still unclean enough, lots of would say. Still, for every gallon of

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

People utilize different blends, varying from 10% grease and 90% petro-diesel to 90% grease and 10% petro-diesel. Some individuals just use it that way, launch and go, without pre-heating it (which makes veg-oil much thinner), and even use 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 a really tough and tolerant motor-- it will not like it but you most likely will not eliminate 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, preferably utilizing pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no requirement for the blends.

Blends with numerous solvents and/or with unleaded gasoline are "experimental at finest", little or nothing is understood about their results on the combustion characteristics of the fuel or their long-lasting effects on the engine.

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

Diesel engines are state-of-the-art devices with really accurate fuel requirements, especially the more modern-day, cleaner-burning diesels (see The TDI-SVO controversy).

They are difficult however they'll only take so much abuse. There's no guarantee of it, but utilizing a blend of up to 20% veg-oil of great quality is said to be safe enough for older diesels, particularly in summer.

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

Just like biodiesel, some kerosene or winterised petro-diesel fuel blended with straight veggie oil decreases the temperature at which it begins to gel. (See Using biodiesel in winter season) More about fuel blending and blends.