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Engine
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 other forms of energy (such as electricity, a flow of hydraulic fluid or compressed air).
A motor car (automobile) has a starter motor and motors to drive pumps (fuel, power steering, etc) – but the power plant that propels the car is called an engine. The term 'motor' was originally used to distinguish the new internal combustion engine -powered vehicles from earlier vehicles powered by a steam engine (as in steam roller and motor roller).
Military engines included siege engines, large catapults, trebuchets and battering rams.
The usage of the term "Engine"
Originally an engine was a mechanical device that converted force into motion. Military devices such as catapults are referred to as siege engines. The term "gin" as in cotton gin is recognised as a short form of the Old French word engin, in turn from the Latin ingenium, related to ingenious. Most devices used in the industrial revolution were referred to as an engine, and this is where the steam engine gained its name.
In more modern usage, the term is used to describe devices that perform mechanical work, follow-ons to the original steam engine. In most cases the work is supplied by exerting a torque, which is used to operate other machinery, generate electricity, pump water or compressed gas. In the context of propulsion systems, an air-breathing engine is one that uses atmospheric air to oxidise the fuel carried, rather than carrying an oxidiser, as in a rocket.
The term is used in computer science in "search engine", "3-D graphics game engine", "rendering engine" and "text-to-speech engine", even though these "engines" are not mechanical and cause no mechanical action (this usage may have been inspired by the "difference engine", an early mechanical computing device[citation needed]).
Antiquity
Simple machines, such as club and oar (examples of the lever), are prehistoric. More complex engines using human power, animal power, water power, wind power and even steam power date back to antiquity. Human power was focused by the use of simple engines, such as the capstan, windlass or treadmill, and with ropes, pulleys, and block and tackle arrangements, this power was transmitted and multiplied. These were used in cranes and aboard ships in Ancient Greece, and in mines, water pumps and siege engines in Ancient Rome. The writers of those times, including Vitruvius, Frontinus and Pliny the Elder, treat these engines as commonplace, so their invention may be far more ancient. By the 1st century AD, various breeds of cattle and horses were used in mills, using machines similar to those powered by humans in earlier times.
According to Strabo, a water powered mill was built in Kaberia in the kingdom of Mithridates in the 1st century BC. Use of water wheels in mills spread throughout the Roman Empire over the next few centuries. Some were quite complex, with aqueducts, dams, and sluices to maintain and channel the water, and systems of gears, or toothed-wheels made of wood with metal, used to regulate the speed of rotation. In a poem by Ausonius in the 4th century, he mentions a stone-cutting saw powered by water. Hero of Alexandria demonstrated both wind and steam powered machines in the 1st century, although it is not known if these were put to any use.
Medieval
During the Muslim Agricultural Revolution from the 7th to 13th centuries, Muslim engineers developed numerous innovative industrial uses of hydropower, early industrial uses of tidal power, wind power, and fossil fuels such as petroleum, and the earliest large factory complexes (tiraz in Arabic).[1] The industrial uses of watermills in the Islamic world date back to the 7th century, while horizontal-wheeled and vertical-wheeled water mills were both in widespread use since at least the 9th century. A variety of industrial mills were invented in the Islamic world, including fulling mills, gristmills, hullers, paper mills, sawmills, ship mills, stamp mills, steel mills, sugar refineries, tide mills, and windmills. By the 11th century, every province throughout the Islamic world had these industrial mills in operation, from the Middle East and Central Asia to al-Andalus and North Africa.[2]
Muslim engineers also invented crankshafts and water turbines, employed gears in mills and water-raising machines, and pioneered the use of dams as a source of water power to provide additional power to watermills and water-raising machines.[3] Such advances made it possible for many industrial tasks that were previously driven by manual labour in ancient times to be mechanized and driven by machinery to some extent in the medieval Islamic world. The transfer of these technologies to medieval Europe later laid the foundations for the Industrial Revolution in 18th century Europe.[2]
In 1206, al-Jazari invented the crankshaft and connecting rod, and employed them in a crank-connecting rod system for two of his water-raising machines. His invention of the crankshaft is considered one of the most important mechanical inventions after the wheel, as it transforms continuous rotary motion into a linear reciprocating motion, and is central to modern machinery such as the steam engine and the internal combustion engine.[4] In 1551, Taqi al-Din invented a practical steam turbine as a prime mover for rotating a spit. A similar steam turbine later appeared in Europe a century later, which eventually led to the steam engine and Industrial Revolution in 18th century Europe.[5]
Modern
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Animation showing the four stages of the 4-stroke combustion engine cycle:1. Induction (Fuel enters)2. Compression3. Ignition (Fuel is burnt)4. Emission (Exhaust out)
English inventor Sir Samuel Morland allegedly used gunpowder to drive water pumps in the 17th century. For more conventional, reciprocating internal combustion engines, the fundamental theory for two-stroke engines was established by Sadi Carnot, France, 1824, whilst the American Samuel Morey received a patent on April 1, 1826. Sir Dugald Clark (1854 – 1932) designed the first two-stroke engine in 1878 and patented it in England in 1881. Automotive production has used a range of energy-conversion systems. These include electric, steam, solar, turbine, rotary, and piston-type internal combustion engines.
Engine cycles
The petrol internal combustion engine, operating on a four-stroke Otto cycle, has been the most successful for automobiles, while diesel engines are used for trucks and buses. Karl Benz was one of the leaders in the development of new engines. In 1878 he began to work on new designs. He concentrated his efforts on creating a reliable gas two-stroke engine that was more powerful, based on Nikolaus Otto's design of the four-stroke engine. Karl Benz showed his real genius, however, through his successive inventions registered while designing what would become the production standard for his two-stroke engine. Benz was granted a patent for it in 1879.
Horizontally-opposed pistons
In 1896, Karl Benz was granted a patent for his design of the first engine with horizontally-opposed pistons. Many BMW motorcycles use this engine type. His design created an engine in which the corresponding pistons move in horizontal cylinders and reach top dead center simultaneously, thus automatically balancing each other with respect to their individual momentums. Engines of this design are often referred to as flat engines because of their shape and lower profile. They must have an even number of cylinders and six, four or two cylinder flat engines have all been common. The most well-known engine of this type is probably the Volkswagen beetle engine. Engines of this type continue to be a common design principle for high performance aero engines (for propellor driven aircraft) and, engines used by automobile producers such as Porsche and Subaru.
Engine development
Mercedes V6 engine in 1996
School model of engine
School model of an engine
Continuance of the use of the internal combustion engine for automobiles is partly due to the improvement of engine control systems (onboard computers providing engine management processes, and electronically controlled fuel injection). Forced air induction by turbocharging and supercharging have increased power outputs and efficiencies available. Similar changes have been applied to smaller diesel engines giving them almost the same power characteristics as petrol engines. This is especially evident with the popularity of smaller diesel engine propelled cars in Europe. Larger diesel engines are still often used in trucks and heavy machinery. They do not burn as clean as gasoline engines, however they have far more torque.
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