How to Make Your Own Fuel #3

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

How to Make Your Own Fuel #2

The only reason you can’t run your car on straight vegetable oil is the viscosity.
It’s OK when hot, but too thick when cold. So you have two choices – either you modify your car or modify your fuel.

If you are going to modify your car, you simply add an extra fuel tank for starting and stopping. You start the car on regular diesel, then when the motor is warm you switch over to the oil. Before you stop, you then just switch back to the diesel.

This is a little like having a dual fuel car, so all the switches and valves and solenoids are readily available. The only decision you need to make is where you’re going to put the extra fuel tank. Because it’s only used for starting and stopping, it doesn’t need to be very big – 10L is plenty. On older cars, a popular spot is inside the engine bay.

The only other modification you need to consider is heating your fuel lines, so the thicker oil can flow from your tank to the engine bay. This is generally done by branching off your cooling system, and it’s possible to get tube-in-tube designs where the fuel line is encased with a cooling line.

The acronym for this option is SVO (Straight Vegetable Oil) and there are plenty of online forums around where the logistics of this process are discussed.
The idea, of course, is that you use waste cooking oil as your fuel, which can be obtained from fish and chip shops and restaurants.

It’s not as easy to get as it used to be, however, as there are now lots of people making their own fuel, so you might have to do a bit of scoping around to find a supplier.

One option of course is fat. Fat is much easier to obtain than cooking oil, as it is more commonly used (and is cheaper).
There are two obvious problems with fat, however – how do you collect it, and how are you going to get it into your tank as fuel?

One option would be to fit an tank into the boot of your car with a wide mouth or clip on lid. Into the bottom of your tank you run a line from your cooling system, so it would melt the oil. With this approach, having a heated line would be mandatory, to stop the fat solidifying as soon as it left the tank.

Tomorrow we’ll look at the other option – modifying the fuel.

How to Make Your Own Fuel

I love diesels for several reasons. One reason is that you can make your own fuel.

A little known fact about diesels is that they were originally designed as an alternative to petroleum fuels. In fact, the very first diesel motor ran on peanut oil.
So what would happen if you tipped some vegetable oil into your diesel fuel tank? Well, nothing. That is, your motor would run fine, and your exhaust would smell like a barbecue. The only problem that would occur is when you turned off your engine and allowed it to cool. When you tried to start it again, it wouldn’t start.

The reason for this is simply viscosity. That is, the injectors in your engine are designed for low viscosity petroleum-based diesel, and not for the thicker vegetable oil.

So if you want to run your car on vegetable oil, this is the only problem you need to get around. There are two ways to do it – you either modify your car, or modify your fuel.

Tomorrow we’ll start looking at how to do it.

Laundry Prewashes #5

The final approach to laundry prewashes is that of the degreaser.

This shouldn’t surprise us, as this is exactly how dry cleaners work, and how the older (and better performing) laundry prewashes work.

The reason simply is that if a stain doesn’t wash out, then very often it is because it is oil-based, and so a degreaser will remove it.

So then what’s the difference between these older laundry prewashes and automotive degreasers? Or to put it another way, can you use automotive degreasers as laundry prewashes?

The main difference between them is the washout. Laundry prewashes were designed to wash out completely in the wash, with no residual solvent smell, and are much more sophisticated formulas.

A recent change in automotive prewashes, however, is the switch away from solvent based formulas to water based formulas, based on alkaline silicates. These products of course have no solvent smell and wash out well, and are an excellent option as a laundry prewash.

So use degreasers based on alkaline salts (such as Diggers or Kenco) for general prewashing, and enzyme based cleaners such as White King for food based stains

Laundry Prewashes #4

Another approach to laundry prewashes is oxidation.

This is an approach where fragile, intensely coloured dye molecules such as those in beetroot, red wine and grass are oxidised by an oxidising chemical. In years gone by, this was achieved by bleach. My mother used to get grass stains out of my cricket whites years ago by soaking them in bleach. It worked, but eventually destroyed the fabric.

A more modern approach these days is to use a gentler bleach that will still destroy the colours but not the fabric. This is generally achieved with perborates, compound salts that release hydrogen peroxide, a chemical that is just strong enough to do the job at low concentrations.

There are two laundry prewashes that use this approach – Preen Oxy Action and SARD Oxy Plus. The Preen works the better of the two. In a recent trial I did for Today Tonight of twelve different laundry prewashes, it was the only one that completely removed the red wine stain.