Biofuels?

Yep, Biofuels - Renewable energy from the biomass. They come in the tree familiar forms of matter: solid, gaseous and liquid. On this site we are mostly considering the liquid forms and of those we are really only looking at vegetable oil based automotive fuels. Other things worth exploring in the future are Methane and Ethanol but for now let's talk about Biodiesel and SVO.

Biodiesel

is a fuel made from chemically altering vegetable oil. Biodiesel will work in any unmodified diesel engine.

Straight Vegetable Oil (SVO)

refers to a diesel engine in a car, tractor, generator or other that has been converted to use unprocessed vegetable oil as its fuel source. The oil can be new and uncooked in or it can be waste oil from food service.

- Using Biodiesel -

Depending on the age of the vehicle there is little or no conversion to use biodiesel. Older cars/trucks with natural rubber hoses and seals are at risk of hose and seal failure do to the solvency of biodiesel. Blending biodiesel with #2 diesel helps guard against this. But sulfur is a pollutant and we don't want it in the fuel in the first place. Generally vehicles made after 95 are safe. More recent vehicles are better. In simple terms: You may need to change the fuel lines and seals to biodiesel compatible material. Some home brewed biodiesel will be more solvent that others because the leftover methanol from the reaction has not been recovered (distilled out of the biodiesel). All commercially sold biodiesel has had this done and there should be no methanol in the fuel.

There is no mechanical conversion that needs to be done to any diesel engine for it to run on biodiesel. It is a direct replacement. It will also replace diesel in many diesel appliances like heaters, stoves, water heaters and so on.

You will need to change your fuel filters if the vehicle is high mileage or really old as the biodiesel will clean the fuel system and clog the filter. This really is a feature though.

What is biodiesel? Biodiesel is non-toxic and biodegradable. It is vegetable oil and sometimes animal fat that has been chemically altered through a process known as transesterification. The glycerin has been separated from the esters with a base (sodium hydroxide or potassium hydroxide mixed with methanol or ethanol to make sodium methoxide, potassium methoxide, sodium ethoxide or potassium ethoxide) and then removed. The esters then bind to the alcohol to form methyl esters or ethyl esters depending on the alcohol you used to make it. Those esters are biodiesel. The sodium hydroxide or potassium hydroxide has almost all fallen into the glycerin and is removed with it.

Where do you get biodiesel? In many cities you can buy it at the pump and in most places you can have it delivered to your home in bulk. You can join the ranks of biodiesel home brewer and make your own. There also may be a biodiesel co-op in your area. Links to resources that will help you accomplish all of this are on the 'Links - Informative Sites' and the 'co-ops and Community' pages.

- Using SVO -

Now, you hear people talking about "I converted my car". These are SVO vehicles - cars and trucks that run on Straight Vegetable Oil. SVO is not biodiesel and biodiesel is not SVO. Biodiesel is no longer an oil really as it was changed with the above or some other proprietary process.

What is involved in conversion is usually the installation of a separate fuel tank and line. This line and tank are heated with hot engine coolant to bring the oil in the line up to ~180F. At that temperature the oil is sufficiently fluid enough to make it through the injectors with the designed spray pattern. The car or truck or generator is started on biodiesel or #2 and run up to operating temperature. By then the vegetable oil is hot enough to be used and you flip a switch to switch from diesel to vegetable oil. About two miles before you destinate you would flip back over to diesel and briefly flush the system, sending a little diesel back through the heat exchange system using another switch. Most diesel engines can be converted. Not all injection pumps can handle the viscous oil. SVO is hard on the engine in some ways. TDI, direct injected engines are more at risk of severe damage than indirect injected engine. The differences are that IDI is injected into a pre chamber where the fuel first swirls and begins to burn and DI is sprayed right over the piston usually with a multi-port nozzle that operates at many times the pressure and timing. If the spray pattern is off or the fuel not hot enough you can get globs that stick to the cylinder walls and cause cylinder ring coking. It can also spray directly onto the piston and cause burn through. Both of these are really, really bad - get a new motor bad. There is also injector coking and deposits that happen and degrade the spray pattern and in my opinion it is more common than people are admitting. This is not to scare you away from SVO. Just be aware and make sure you know the risks and safeguards. If your system was installed well and you don't forget to flush and switch to biodiesel before you shut down and make sure your oil is hot before you switch to SVO, then you have a good chance of avoiding the pitfalls of experimental fuels. Biodiesel has none of these problems.

There is a heap more information to be found by following links on the links page.