Right, now we get into a bit of chemistry.
Your diesel car will run fine on cooking oil but it’s too viscous, so what we have to do is reduce the viscosity. This is the only reason you need to modify the oil. It’s all about viscosity, so that when your car starts from cold in the morning, the liquid is thin enough that your injectors can inject it into the engine.
So how do we modify it? Well let’s have a look at what an oil molecule looks like. Essentially it’s shaped like an uppercase E. The horizontal lines are long carbon chains and the vertical line is a three carbon glyceride. This is where we get that term triglyceride from. The physical structure of the molecule makes it quite bulky, and this is why oil is quite thick, as the bulky structure means that the molecules don’t flow over each other very easily.
So to reduce the viscosity, we need to break up this structure. Essentially what we are doing is splitting off the three horizontal carbon chains from the glyceride backbone.
This is done with a process called transesterification.
if you look on the web you will find plenty of information about it, but unfortunately, a lot of it is wrong. The standard method of doing this involves complex measurements of the oil content, followed by a process where the oil is heated, and then cleaning processes afterwards. The reason that people use these methods is that they don’t understand much chemistry.
For this reason, I designed my own method, which is foolproof and works at room temperature. Details are here. Tomorrow I’ll talk about which cars run best on bio diesel