|MadSci Network: Engineering|
Gasoline and diesel fuel are very similar. Gasoline is the portion of crude oil that boils between about 100 and 400 degrees F. Diesel fuel is the portion of crude oil that boils between about 400 and 600 degrees F. However, an ordinary diesel engine will not run on gasoline and a gasoline engine will not run on diesel fuel. A gasoline engine engine works by compressing a mixture of gasoline vapors and air in a cylinder and igniting it with a spark, driving the piston and creating the power. A diesel engine works by compressing air in a cylinder and injecting a liquid fuel into the cylinder. The air must be compressed to a high enough pressure (much higher than a gasoline engine's pressure) that it will be hot enough to ignite the fuel without a spark. If you try to run a gasoline engine on diesel fuel the fuel will not be vaporized satisfactorily and if it ran at all it would be sluggish and would exhaust a cloud of smoke. If you try to run a diesel engine on gasoline the gasoline will vaporize and ignite prematurely and the engine will sputter and knock and eventually stall. (I know this from experience because I once rented a car that I did not know had a diesel engine and I filled the tank with gasoline). Kerosene and jet fuel are portions of crude oil that are similar to diesel except that they usually will not contain the highest boiling part. They should work in a diesel engine, but not in a gasoline engine. All of these fuels - gasoline, kerosene, jet fuel, and diesel fuel - are separated from crude oil in an oil refinery to produce fuels that are formulated for their intended uee. There would be no advantage in trying to design engines to run on fuel that is not suited for them. Diesel engines will run on many liquid fuels other than diesel oil. This would include such products as animal fat and vegetable oil. These fuels have the advantage of being renewable rather that limited in suply like oil and coal. This is called biodiesel that may become very important in the future.
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