Biodiesel

This page is Work In Progress and therefore may not be complete.

Biodiesel (chemical name Fatty Acid Methyl Esters), has very similar combustion properties to mineral Diesel, making it a suitable substitute for mineral Diesel in road vehicles.

Biodiesel should not be confused with vegetable oil, or blends of vegetable oil with solvents such as Petrol.

Advantages

Biodiesel presents several advantages over pure vegetable oil as a road fuel:

• significantly reduced viscosity; good for systems with weak mechanical injection pumps (EG Lucas, which can shear its driveshaft with vegetable oil)
• lower melt point; can be used in winter
• can be safely cold-started; no piston ring gumming and resulting loss of compression

How it is made

Biodiesel is made from vegetable oil using a chemical process to split the vegetable oil molecules. This is done in a biodiesel processor.

Blends

B5, B30 and B100 refer to blends of biodiesel with mineral Diesel. B30 is 30% mineral Diesel, 70% Biodiesel. Some vehicles run happily on B100, whereas for others, the manufacturer may specify a maximum blend. Ambient temperature is also an influencing factor, as Biodiesel can "wax up" before mineral Diesel at lower temperatures.

Quality standards

The European standard for Biodiesel is EN14214, although in the UK commercial producers are not legally required to produce fuel meeting this standard. Buyer beware.

In the US this standard is ASTM D 6751.