An engine is a mechanical device that produces some form of output from a given input.

An engine whose purpose is to produce kinetic energy output from a fuel source is called a prime mover; alternatively, a motor is a device which produces kinetic energy from a preprocessed "fuel" (such as electricity, a flow of hydraulic fluid or compressed air).

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This is one terrific site & it must have taken many hours to build:

http://www.keveney.com/Engines.html

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