Vegetable Oil Kits for direct use in Diesel Engines

There are a number of kits on the market that allow someone to modify their car to directly use vegetable oil.

A typical conversion kit will have the following components:

1. vegetable oil tank - The tank holds the vegetable oil used for fuel separate from the regular diesel tank already in the car
2. filter - the filter is designed to remove any impurities that might be in the vegetable oil
3. tubing - the tubes connect the vegetable oil tank to the combustion chambers in the diesel engine
4. valves - this controls the flow of vegetable oil
5. switches - usually mounted on the dashboard which can be used to control the valves and therefore the flow of vegetable oil to the engine
6. pre-heater - the pre-heater heats the vegetable oil so that it can flow to the combustion chamber

Vegetable oil is much thicker than diesel oil and so, as noted above, it needs to be heated to 165 degrees or higher in order to thin it out enough to use. Consequently most vegetable oil conversion kits provide some type of vegetable oil pre-heater to thin the oil out so the engine can be started. There are two approaches that are commonly taken to heating the oil. One approach is to use an electric heater to heat the oil. Another approach is to run the engine for a while on conventional diesel fuel, and then use the heat from the engine to heat the oil using heat exchangers.

Because of the need to pre-heat the vegetable oil the car must usually be run for about five minutes before you can throw the switch to have it begin using the vegetable oil. The switch triggers a valve which opens the flow of vegetable oil from the now heated tank and cuts off the flow of fuel from the standard diesel tank. This process must then be reversed when you shut the engine down. Five minutes before you turn the engine off you will need to turn the switch back to conventional diesel so that the fuel lines are purged of any vegetable oil which could condense and clog the engine.

Vegetable oil kits have some definite disadvantages. First, one most own a car with a diesel engine. Second you need to establish a source for getting your vegetable oil. This is probably much less of an issue since fast food restaurants that use them are just about everywhere. Third, there is the expense of the conversion kit.. If you are not mechanically inclined it is likely that most good mechanics could put them in for you but that will add further cost. Finally, there is the issue just described of having to deal with switching fuels when starting and stopping your car. If you have the kind of lifestyle where you are doing quick short trips with your car then this requirement may be a bit more than you want to deal with.

On the other hand vegetable oil cars can for some people prove to be an ideal alternative. It uses a fuel that is completely renewable and which could help support our agricultural economy. The fuel is likely to be extremely cheap, possible even free if you have a good relationship with your local fast food owner. The engine uses fuel that would have otherwise gone into a polluting landfill and it produces less hydrocarbons than conventional diesel fuel. These are not insignificant advantages in an era of global warming and high fuel prices.