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

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

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 methods sound most convenient, but, as so frequently in life, it's not rather that simple.

1. Mixing it

Grease is far more viscous (thicker) than either petro-diesel or biodiesel. The purpose of mixing it or blending it with other fuels is to reduce the viscosity to make it thinner so that it streams more easily 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 using fossilfuel-- cleaner than many, however still not clean enough, lots of would say. Still, for every single gallon of

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

People utilize various blends, varying from 10% grease and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some individuals just use it that method, begin up and go, without pre-heating it (that makes veg-oil much thinner), or 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 hard and tolerant motor-- it will not like it but you most likely won't eliminate it. Otherwise, it's not sensible.

To do it appropriately 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 need for the mixes.

Blends with different solvents and/or with unleaded fuel are "speculative at best", little or absolutely nothing is learnt about their impacts on the combustion attributes of the fuel or their long-term impacts on the engine.

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

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

They are difficult however they'll just take a lot abuse. There's no assurance of it, however utilizing a mix of as much as 20% veg-oil of great quality is stated to be safe enough for older diesels, specifically in summertime.

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

Just like biodiesel, some kerosene or winterised petro-diesel fuel blended with straight grease lowers the temperature level at which it begins to gel. (See Using biodiesel in winter) More about fuel mixing and blends.