Originally Posted by JDNSW
				
			
			Volatility has nothing to do with it. Get cooking oil hot enough (by compressing the air) and mix it with air and it will ignite very readily - look at the number of cooking fires there are, almost all starting from  cooking oil. Diesel ships engines run on stuff that is far less volatile than cooking oil - looks more like tar.
There is nothing magic about petroleum based fuels - diesel engines have run on straight non mineral oil since the first diesels, and petrol engines have run on alchohol or producer gas from wood since the nineteenth century, with no mineral content in the fuel at all. 
Its just that most modern engines are quite fussy about the fuel they use for a whole variety of reasons, but none of them are because they need some magic mineral ingredient.
John