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فرمت فایل:Word (قابل ویرایش و آماده پرینت)
تعداد صفحه:7
فهرست:
Engine development
Pollution concerns
Air-breathing engines
Increasing power
Combustion efficiency
Examples
Environmental effects
Air quality
[edit] Sound levels
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]
تحقیق در مورد(به زبان انگلیسی) Engine