Cars the run on vegetable oil work just like any other car except that they burn a fuel that comes right from the deep fryer and is strained through a simple filter. The reason they can run on vegetable oil is in how the engine works. Unlike a combustion engine, which is powered by an explosion in the piston chamber, a car that runs on vegetable oil is a converted diesel engine, that is compression-driven. That means there is no spark to ignite the fuel. Instead the engine compresses the fuel and causes it to explode, without an electrical spark.
Misconceptions
Vegetable oil cars do not have a completely different engine. Many Straight Vegetable Oil (SVO) cars are simple converted diesel engines that use a simple grease converter to run on vegetable oil. Since diesel fuel is much oilier than gas, the conversion process is possible. In addition, these cars can run on fuel that comes right out of a deep fryer. It is simply filtered and then poured right into the gas tank.
The Facts
An SVO car is much more cost-effective only if you drive long distances. Vegetable oil needs to be heated to work properly in an engine, otherwise it is too viscous. SVO cars need to be run partially from diesel fuel. Typically you must start you car on diesel fuel until the oil is warm enough to run through the engine. SVO cars also need to be stopped on diesel fuel. Kits to convert a normal diesel car into a vegetable oil-burning car can be purchased from anywhere from $400 to $800. SVO cars can get significant MPG (of veggie oil) but the main cost savings is that the fuel is free and can be picked up from restaurants that are typically happy to get rid of it.
Benefits
Cost savings is the biggest benefit when using a vegetable oil-powered vehicle. The savings over conventional fuel is great enough to compensate for the additional time spent filtering the fuel and fetching it from restaurants. You also are burning a "greener" fuel, as the fuel burns cleaner and is much cleaner to produce. Fewer chemicals are used to process it and there is no drilling involved which also can harm the environment.
Risk Factors
Burning vegetable oil in your car isn't all roses and corn. The viscous fuel can cause problems in your engine, as gunk and deposits are likely to build up in vital engine parts. However, you can be careful to filter your oil, and greatly reduce the risk of build-up. Mainly build-up comes when dirty fuels with carbon from cooked food is run through the engine. There is little risk in loss of power, or engine performance, although over the long term, running a car designed for diesel fuel, might impact engine performance to some degree.
Invented
Many historians (and veggie car fanatics) have said that the first engine, the diesel engine was actually designed to run on SVO. However, some believe that oil interests had a say in what engine became more popular and which fuel was eventually used in the diesel engine, which was more suitable for large trucks. Technology has always been around to run a car on vegetable oil and recently there have been many improvements to the conversion kits.
Tags: diesel fuel, diesel engine, comes right, converted diesel, deep fryer, engine performance