Vegetable Oil is just that, vegetable oil. Rather than modifying the fuel to make it more compatible with the engine, the engine is modified to make it more compatible with the fuel.
Sometimes new cooking oil is used (often referred to as SVO) and sometimes used cooking oil is used (often referred to as UCO or WVO).
Unfortunately with 99% of engines you cannot just stick it in your tank and go, a proper good quality kit must be fitted.
Two tank systems involve adding an extra fuel tank to your system. One of the tanks contains the vegetable oil and the other contains regular diesel (or indeed biodiesel). The engine is started on the diesel and run for a few miles to warm up before switching over on to the vegetable oil; the heat from the engine used to make the vegetable oil more runny and diesel like. When approaching your destination you switch back to diesel ensuring that the engine has diesel in it the next time it starts up from cold. The disadvantage of this system is that you have two tanks to worry about and you have to remember to switch over and switch back again and you loose some space to the additional tank. The advantages are that the kit is a little cheaper, the conversion a little easier, the conversion is reversible and the kit can generally be transferred to another vehicle.
One tank systems also exist but only for specific engines. The vehicle is started on vegetable oil, run about on vegetable oil and stopped on vegetable oil (or indeed on biodiesel or dino-diesel, you are not limited to just vegetable oil); to drive it is exactly the same as an unconverted engine, with no switches to worry about. The conversion is a little more involved and the kit a little more expensive but the advantage is obvious. Uhe kit is not so easily transferred to a new vehicle.
Buy my book
I have written a book on biofuels, biodiesel and vegetable oil for McGraw-Hill, it will be published in late Summer 2008 - read more about it here - and find it on Amazon here.
