<P> The word engine derives from Old French engin, from the Latin ingenium--the root of the word ingenious . Pre-industrial weapons of war, such as catapults, trebuchets and battering rams, were called siege engines, and knowledge of how to construct them was often treated as a military secret . The word gin, as in cotton gin, is short for engine . Most mechanical devices invented during the industrial revolution were described as engines--the steam engine being a notable example . However, the original steam engines, such as those by Thomas Savery, were not mechanical engines but pumps . In this manner, a fire engine in its original form was merely a water pump, with the engine being transported to the fire by horses . </P> <P> In modern usage, the term engine typically describes devices, like steam engines and internal combustion engines, that burn or otherwise consume fuel to perform mechanical work by exerting a torque or linear force (usually in the form of thrust). Devices converting heat energy into motion are commonly referred to simply as engines . Examples of engines which exert a torque include the familiar automobile gasoline and diesel engines, as well as turboshafts . Examples of engines which produce thrust include turbofans and rockets . </P> <P> When the internal combustion engine was invented, the term motor was initially used to distinguish it from the steam engine--which was in wide use at the time, powering locomotives and other vehicles such as steam rollers . The term motor derives from the Latin verb moto which means to set in motion, or maintain motion . Thus a motor is a device that imparts motion . </P> <P> Motor and engine later came to be used largely interchangeably in casual discourse . However, technically, the two words have different meanings . An engine is a device that burns or otherwise consumes fuel, changing its chemical composition, whereas a motor is a device driven by electricity, air, or hydraulic pressure, which does not change the chemical composition of its energy source . However, rocketry uses the term rocket motor, even though they consume fuel . </P>

How do i find out what engine i have