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

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

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, however, as so typically in life, it's not rather that basic.

1. Mixing it

Vegetable oil is a lot more viscous (thicker) than either petro-diesel or biodiesel. The function of mixing it or mixing it with other fuels is to lower 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 using fossilfuel-- cleaner than the majority of, however still not tidy enough, many would say. Still, for each gallon of

vegetable oil you utilize, that's one gallon of fossil-fuel saved, and that much less climate-changing carbon in the environment.

People use various blends, varying from 10% vegetable oil and 90% petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people just utilize it that way, begin up and go, without pre-heating it (which makes veg-oil much thinner), or even utilize pure vegetable oil 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 very difficult and tolerant motor-- it won't like it however you most likely won't eliminate it. Otherwise, it's not wise.

To do it appropriately you'll require what amounts to an SVO system with anyhow, preferably utilizing pure petro-diesel or biodiesel for starts and stops. (See next.) In which case there's no need for the mixes.

Blends with various solvents and/or with unleaded gasoline are "experimental at best", little or absolutely nothing is learnt 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 different chemical properties and combustion attributes from the petroleum diesel fuel for which diesel engines and their fuel systems are designed.

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

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

Otherwise utilizing veg-oil fuel requires either a professional SVO option or biodiesel. Mixes and blends are usually a bad compromise. But blends do have an advantage in winter.

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