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Internal combustion engine/ماكنة الاحتراق الداخلي

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    الصورة الرمزية حسن هادي
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    Internal combustion engine/ماكنة الاحتراق الداخلي

    نرفق لكم اخوتنا الاعزاء في سلسلة المواضيع المدرجة ذات الارتباط النسبي من ناحية التداخل في بعض المعادلات او الدورات الحرارية موضوعا مبسطا عن ماكنة الاحتراق الداخلي في عدة مشاركات *لغرض اتمام الفائدة ولتسهيل عملية البحث عن تفاصيل هذا الموضوع ومن الله التوفيق*
    ************************************************** *****Internal combustion engine
    From Wikipedia, the free encyclopedia

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    The internal combustion engine is an engine in which the combustion of fuel and an oxidizer (typically air) occurs in a confined space called a combustion chamber. This exothermic reaction creates gases at high temperature and pressure, which are permitted to expand. The defining feature of an internal combustion engine is that useful work is performed by the expanding hot gases acting directly to cause movement of solid parts of the engine, by acting on pistons, rotors, or even by pressing on and moving the entire engine itself.
    This contrasts with external combustion engines, such as steam engines and Stirling engines, which use an external combustion chamber to heat a separate working fluid, which then in turn does work, for example by moving a piston or a turbine.
    The term Internal Combustion Engine (ICE) is almost always used to refer specifically to reciprocating piston engines, Wankel engines and similar designs in which combustion is intermittent. However, continuous combustion engines, such as jet engines, most rockets and many gas turbines are also internal combustion engines


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    Four-stroke cycle (or Otto cycle)
    1. intake
    2. compression
    3. power
    4. exhaust

    تقبلوا تحياتي اخوكم حسن

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    حسن هادي
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    عضو متميز
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    ندرج لكم ادناه روابط الموضوع المتشعبة لكي يتسنى لكم تتبع الرابط الذي تحتاجونه *
    ************************************************** ********************
    *******s

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    حسن هادي
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    عضو متميز
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    لمحات تاريخية
    ***********
    History

    A colorized automobile engine



    Early internal-combustion engines were used to power farm equipment similar to these models.


    The first internal combustion engines did not have compression, but ran on air/fuel mixture sucked or blown in during the first part of the intake stroke. The most significant distinction between modern internal combustion engines and the early designs is the use of compression and in particular of in-cylinder compression.
    • 1206: Al-Jazari demonstrates an early rotary to reciprocating motion, which is a waterwheel-powered pump
    • 1509: Leonardo da Vinci described a compression-less engine.
    • 1673: Christiaan Huygens described a compression-less engine.
    • 17th century: English inventor Sir Samuel Morland used gunpowder to drive water pumps, essentially creating the first rudimentary internal combustion engine.
    • 1780's: Alessandro Volta built a toy electric pistol ([1]) in which an electric spark exploded a mixture of air and hydrogen, firing a cork from the end of the gun.
    • 1794: Robert Street built a compression-less engine whose principle of operation would dominate for nearly a century.
    • 1806: Swiss engineer François Isaac de Rivaz built an internal combustion engine powered by a mixture of hydrogen and oxygen.
    • 1823: Samuel Brown patented the first internal combustion engine to be applied industrially. It was compression-less and based on what Hardenberg calls the "Leonardo cycle," which, as this name implies, was already out of date at that time.
    • 1824: French physicist Sadi Carnot established the thermodynamic theory of idealized heat engines. This scientifically established the need for compression to increase the difference between the upper and lower working temperatures.
    • 1826 April 1: The American Samuel Morey received a patent for a compression-less "Gas Or Vapor Engine".
    • 1838: a patent was granted to William Barnet (English). This was the first recorded suggestion of in-cylinder compression.
    • 1854: The Italians Eugenio Barsanti and Felice Matteucci patented the first working efficient internal combustion engine in London (pt. Num. 1072) but did not go into production with it. It was similar in concept to the successful Otto Langen indirect engine, but not so well worked out in detail.
    • 1856: in Florence at Fonderia del Pignone (now Nuovo Pignone, a subsidiary of General Electric) Pietro Benini realized a working prototype of the Barsanti-Matteucci engine, supplying 5 HP. In subsequent years he developed more powerful engines - with one or two pistons - which served as steady power sources, replacing steam engines.
    • 1860: Jean Joseph Etienne Lenoir (1822 - 1900) produced a gas-fired internal combustion engine closely similar in appearance to a horizontal double-acting steam beam engine, with cylinders, pistons, connecting rods, and flywheel in which the gas essentially took the place of the steam. This was the first internal combustion engine to be produced in numbers.
    • 1862: German inventor Nikolaus Otto designed an indirect-acting free-piston compression-less engine whose greater efficiency won the support of Langen and then most of the market, which at that time, was mostly for small stationary engines fueled by lighting gas.
    • 1870: In Vienna Siegfried Marcus put the first mobile gasoline engine on a handcart.
    • 1876: Nikolaus Otto working with Gottlieb Daimler and Wilhelm Maybach developed a practical four-stroke cycle (Otto cycle) engine. The German courts, however, did not hold his patent to cover all in-cylinder compression engines or even the four stroke cycle, and after this decision in-cylinder compression became universal.

    Karl Benz


    • 1879: Karl Benz, working independently, was granted a patent for his internal combustion engine, a reliable two-stroke gas engine, based on Nikolaus Otto's design of the four-stroke engine. Later Benz designed and built his own four-stroke engine that was used in his automobiles, which became the first automobiles in production.
    • 1882: James Atkinson invented the Atkinson cycle engine. Atkinson’s engine had one power phase per revolution together with different intake and expansion volumes making it more efficient than the Otto cycle.
    • 1891 - Herbert Akroyd Stuart built his oil engine, leasing rights to Hornsby of England to build them. They build the first cold start, compression ignition engines. In 1892, they installed the first ones in a water pumping station. An experimental higher-pressure version produced self-sustaining ignition through compression alone in the same year.
    • 1892: Rudolf Diesel developed his Carnot heat engine type motor burning powdered coal dust.
    • 1893 February 23: Rudolf Diesel received a patent for the diesel engine.
    • 1896: Karl Benz invented the boxer engine, also known as the horizontally opposed engine, in which the corresponding pistons reach top dead centre at the same time, thus balancing each other in momentum.
    • 1900: Rudolf Diesel demonstrated the diesel engine in the 1900 Exposition Universelle (World's Fair) using peanut oil (see biodiesel).
    • 1900: Wilhelm Maybach designed an engine built at Daimler Motoren Gesellschaft—following the specifications of Emil Jellinek—who required the engine to be named Daimler-Mercedes after his daughter. In 1902 automobiles with that engine were put into production by DMG.

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    الروابط فعالة

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    حسن هادي
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    عضو متميز
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    Applications

    Internal combustion engines are most commonly used for mobile propulsion in automobiles, equipment, and other portable machinery. In mobile equipment internal combustion is advantageous, since it can provide high power to weight ratios together with excellent fuel energy-density. These engines have appeared in transport in almost all automobiles, trucks, motorcycles, boats, and in a wide variety of aircraft and locomotives, generally using petroleum (called All-Petroleum Internal Combustion Engine Vehicles or APICEVs) . Where very high power is required, such as jet aircraft, helicopters and large ships, they appear mostly in the form of turbines.
    They are also used for electric generators (i.e. 12 V generators) and by industry.

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    حسن هادي
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    عضو متميز
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    Operation

    All internal combustion engines depend on the exothermic chemical process of combustion: the reaction of a fuel, typically with the oxygen from the air, although other oxidizers such as nitrous oxide may be employed. Also see stoichiometry.
    The most common modern fuels are made up of hydrocarbons and are derived from mostly petroleum. These include the fuels known as dieselfuel, gasoline and petroleum gas, and the rarer use of propane gas. Most internal combustion engines designed for gasoline can run on natural gas or liquefied petroleum gases without major modifications except for the fuel delivery components. Liquid and gaseous biofuels, such as Ethanol and biodiesel, a form of diesel fuel that is produced from crops that yield triglycerides such as soy bean oil, can also be used. Some can also run on Hydrogen gas.
    All internal combustion engines must achieve ignition in their cylinders to create combustion. Typically engines use either a spark ignition (SI) method or a compression ignition (CI) system. In the past other methods using hot tubes or flames have been used

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    حسن هادي
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    عضو متميز
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    ارجو ان يكون تسلسل الموضوع بصورة جيدة ومفيدة وتقبلوا تحياتي

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    حسن هادي
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    عضو متميز
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    Petroleum internal combustion engines
    Main article: Petroleum

    [edit] Gasoline Ignition Process

    Electrical/Gasoline-type ignition systems (that can also run on other fuels as previously mentioned) generally rely on a combination of a lead-acid battery and an induction coil to provide a high voltage electrical spark to ignite the air-fuel mix in the engine's cylinders. This battery can be recharged during operation using an electricity-generating device, such as an alternator or generator driven by the engine. Gasoline engines take in a mixture of air and gasoline and compress to less than 185 psi and use a spark plug to ignite the mixture when it is compressed by the piston head in each cylinder.

    [edit] Diesel Engine Ignition Process

    Compression ignition systems, such as the diesel engine and HCCI engines, rely solely on heat and pressure created by the engine in its compression process for ignition. Compression that occurs is usually more than three times higher than a gasoline engine. Diesel engines will take in air only, and shortly before peak compression, a small quantity of diesel fuel is sprayed into the cylinder via a fuel injector that allows the fuel to instantly ignite. HCCI type engines will take in both air and fuel but will continue to rely on an unaided auto-combustion process due to higher pressures and heat. This is also why diesel and HCCI engines are also more susceptible to cold starting issues though they will run just as well in cold weather once started. Most diesels also have battery and charging systems, however this system is secondary and is added by manufacturers as luxury for ease of starting, turning fuel on and off (which can also be done via a switch or mechanical apparatus), and for running auxiliary electrical components and accessories. Most old engines, however, rely on electrical systems that also control the combustion process to increase efficiency and reduce emissions.

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  9. [9]
    حسن هادي
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    عضو متميز
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    Energy and pollution
    Once ignited and burnt, the combustion products, hot gases, have more available energy than the original compressed fuel/air mixture (which had higher chemical energy). The available energy is manifested as high temperature and pressure which can be translated into work by the engine. In a reciprocating engine, the high pressure product gases inside the cylinders drive the engine's pistons.
    Once the available energy has been removed, the remaining hot gases are vented (often by opening a valve or exposing the exhaust outlet) and this allows the piston to return to its previous position (Top Dead Center - TDC). The piston can then proceed to the next phase of its cycle, which varies between engines. Any heat not translated into work is normally considered a waste product, and is removed from the engine either by an air or liquid cooling system.

    [edit] Engine Efficiency

    The efficiency of various types of internal combustion engines vary, but it is lower than electric motor energy efficiency. Most gasoline fueled internal combustion engines, even when aided with turbochargers and stock efficiency aids, have a mechanical efficiency of about 20% [1][2]. The efficiency may be as high as 37% at the optimum operating point in engines where this is a high priority such as that of the Prius. Most internal combustion engines waste about 36% of the energy in gasoline as heat lost to the cooling system and another 38% through the exhaust. The rest, about 6%, is lost to friction.
    Hydrogen Fuel Injection, or HFI, is an engine add on system that improves the fuel economy of internal combustion engines by injecting hydrogen as a combustion enhancement into the intake manifold. Fuel economy gains of 15% to 50% can be seen[citation needed]. A small amount of hydrogen added to the intake air-fuel charge increases the octane rating of the combined fuel charge and enhances the flame velocity, thus permitting the engine to operate with more advanced ignition timing, a higher compression ratio, and a leaner air-to-fuel mixture than otherwise possible. The result is lower pollution with more power and increased efficiency. Some HFI systems use an on board electrolyzer to generate the small amount of hydrogen needed in the system, around 5% of total Btu. A small tank of pressurized hydrogen can also be used, but this method necessitates refilling. Hydrogen in liquid form is seldom used because it is difficult to store.
    There has also been discussion of new types of internal combustion engines, such as the Scuderi Split Cycle Engine, that utilize high compression pressures in excess of 2000 psi and combust after top-dead-center (the highest & most compressed point in an internal combustion piston stroke). The claimed efficiency of this engine, by calculation, is 42%. This has yet to be demonstrated as of March 2007.

    [edit] Engine pollution

    Main article: Global warming
    Generally internal combustion engines, particularly reciprocating internal combustion engines, produce moderately high pollution levels, due to incomplete combustion of carbonaceous fuel, leading to carbon monoxide and some soot along with oxides of nitrogen & sulfur and some unburnt hydrocarbons depending on the operating conditions and the fuel/air ratio. The primary causes of this are the need to operate near the stoichiometric ratio for petrol engines in order to achieve combustion (the fuel would burn more completely in excess air) and the "quench" of the flame by the relatively cool cylinder walls. Quenching is commonly observed in diesel (compression ignition) engines which run on natural gas, when running at lower speed. It dramatically reduces the efficiency and increases knocking and might cause the engine to stall.
    Diesel engines produce a wide range of pollutants including aerosols of many small particles (PM10) that are believed to penetrate deeply into human lungs. Engines running on liquified petroleum gas (LPG) are very low in emissions as LPG burns very cleanly and does not contain sulphur or lead.
    • Many fuels contain sulfur leading to sulfur oxides (SOx) in the exhaust, promoting acid rain.
    • The high temperature of combustion creates greater proportions of nitrogen oxides (NOx), demonstrated to be hazardous to both plant and animal health.
    • Net carbon dioxide production is not a necessary feature of engines, but since most engines are run from fossil fuels this usually occurs. If engines are run from biomass, then no net carbon dioxide is produced as the growing plants absorb as much, or more carbon dioxide while growing.
    • Hydrogen engines need only produce water, but when air is used as the oxidizer nitrogen oxides are also produced.

    [edit] Parts


    An illustration of several key components in a typical four-stroke engine


    For a four-stroke engine, key parts of the engine include the crankshaft (purple), one or more camshafts (red and blue) and valves. For a two-stroke engine, there may simply be an exhaust outlet and fuel inlet instead of a valve system. In both types of engines, there are one or more cylinders (grey and green) and for each cylinder there is a spark plug (darker-grey), a piston (yellow) and a crank (purple). A single sweep of the cylinder by the piston in an upward or downward motion is known as a stroke. The downward stroke that occurs directly after the air/fuel mix passes from the carburetor to the cylinder where it is ignited is known as a power stroke.
    A Wankel engine has a triangular rotor that orbits in an epitrochoidal (figure 8 shape) chamber around an eccentric shaft. The four phases of operation (intake, compression, power, exhaust) take place in separate locations, instead of one single location as in a reciprocating engine.
    A Bourke Engine uses a pair of pistons integrated to a Scotch Yoke that transmits reciprocating force through a specially designed bearing assembly to turn a crank mechanism. Intake, compression, power, and exhaust occur in each stroke.

    [edit] Classification

    The fundamental difference between an engine and a motor is that a motor converts electricity into mechanical energy whereas an engine converts thermal energy into mechanical energy. At one time, the word "engine" (from Latin, via Old French, ingenium, "ability") meant any piece of machinery — a sense the persists in expressions such as siege engine. A "motor" (from Latin motor, "mover") is any machine that produces mechanical power. Traditionally, electric motors are not referred to as "engines," but combustion engines are often referred to as "motors." (An electric engine refers to locomotive operated by electricity).
    However, many people consider engines as those things which generate their power from within, and motors as requiring an outside source of energy to perform their work

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    حسن هادي
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    عضو متميز
    الصورة الرمزية حسن هادي


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