Can you run engines on vegetable oil?

Question

Because I know you can run them on spices, Mussolini made the trains run on thyme :D

Thank you thank you, I'm here all week. :)

Answer 1

Maybe, not.

But you can make the machine work smoothly by placing amount of vegetable oil on it.

Answer 2

Yes.  It's usually called a grease car or straight vegetable oil (SVO).   Only diesel engines can be run on SVO.  Actually, diesel engines can be run on almost any flammable liquid, as long as they are tuned for the correct air/fuel mixture.  This is because diesels inject fuel after compression and the fuel burns while its being injected.   The only requirement is that the fuel be injectable.  Because vegetable oil is very thick, it must be preheated to make it injectable.  For this reason you can't pour peanut oil directly into your diesel tank, but you need a minor modification of the cooling system to use the engine heat to preheat the SVO.  

Engines that run on gasoline rely on the very specific combustion properties of gasoline, mainly that it does not flash, or precombust, while being compressed.  The octane rating is a measure of how resistant it is to this uncontrolled combustion that can cause engine knocking.  Most any random flammable liquid would have much too low of an octane rating and would not work in a standard gasoline engine.