Fuel
Fossil Fuels
Engines require fuel to run, and in automobiles that usually refers to gasoline or diesel, sometimes referred to as fossil fuels. Fossil fuels, when mixed with oxygen, will ignite and explode, expelling energy which is captured by the Engine and converted into kinetic energy. After burning, the fuel changes to Exhaust, which is carried our of the engine through the Exhaust manifold and away form the car by the Exhaust pipes.
Bio-Fuels
In an effort to offset the amount of carbon released into the atmosphere as "greenhouse gases", the US federal government, consumers and oil companies are trying alternative "bio-fuels", such as ethanol (made from corn), and bio-diesel, which can be made from a variety of vegetable oils.
Most gasoline sold in the United States has at least some ethanol in it, and some vehicles have been specially built to use "flex fuel", which is 85% ethanol.
Most Diesel engines can run on commercially sold bio-diesel, but they have to be modified to run on different types of vegetable oils.
