An engine or motor is a machine designed to convert one or more forms of energy into mechanical energy .
103-796: The Northrop BT was an American two-seat, single- engine monoplane dive bomber built by the Northrop Corporation for the United States Navy . At the time, Northrop was a subsidiary of the Douglas Aircraft Company . While unsuccessful in its own right, the BT was subsequently redesigned into the Douglas SBD Dauntless , which would form the backbone of the Navy's dive bomber force. The design of
206-817: A candle 's flame takes the shape of a sphere. ). Microgravity combustion research contributes to the understanding of a wide variety of aspects that are relevant to both the environment of a spacecraft (e.g., fire dynamics relevant to crew safety on the International Space Station ) and terrestrial (Earth-based) conditions (e.g., droplet combustion dynamics to assist developing new fuel blends for improved combustion, materials fabrication processes , thermal management of electronic systems , multiphase flow boiling dynamics, and many others). Combustion processes that happen in very small volumes are considered micro-combustion . The high surface-to-volume ratio increases specific heat loss. Quenching distance plays
309-412: A detonation . The type of burning that actually occurs depends on the degree to which the fuel and oxidizer are mixed prior to heating: for example, a diffusion flame is formed if the fuel and oxidizer are separated initially, whereas a premixed flame is formed otherwise. Similarly, the type of burning also depends on the pressure: a detonation, for example, is an autoignitive reaction front coupled to
412-451: A fuel cell without side production of NO x , but this is an electrochemical engine not a heat engine. 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
515-399: A triplet spin state . Bonding can be described with three bonding electron pairs and two antibonding electrons, with spins aligned, such that the molecule has nonzero total angular momentum. Most fuels, on the other hand, are in a singlet state, with paired spins and zero total angular momentum. Interaction between the two is quantum mechanically a " forbidden transition ", i.e. possible with
618-482: A chemical reaction, but are not heat engines. Examples include: An electric motor uses electrical energy to produce mechanical energy , usually through the interaction of magnetic fields and current-carrying conductors . The reverse process, producing electrical energy from mechanical energy, is accomplished by a generator or dynamo . Traction motors used on vehicles often perform both tasks. Electric motors can be run as generators and vice versa, although this
721-444: A cigarette, a short-circuited wire) and the persistent combustion of biomass behind the flaming fronts of wildfires . Spontaneous combustion is a type of combustion that occurs by self-heating (increase in temperature due to exothermic internal reactions), followed by thermal runaway (self-heating which rapidly accelerates to high temperatures) and finally, ignition. For example, phosphorus self-ignites at room temperature without
824-454: A cold cylinder, which are attached to reciprocating pistons 90° out of phase. The gas receives heat at the hot cylinder and expands, driving the piston that turns the crankshaft . After expanding and flowing through the recuperator, the gas rejects heat at the cold cylinder and the ensuing pressure drop leads to its compression by the other (displacement) piston, which forces it back to the hot cylinder. Non-thermal motors usually are powered by
927-548: A few limited-production battery-powered electric vehicles have appeared, they have not proved competitive owing to costs and operating characteristics. In the 21st century the diesel engine has been increasing in popularity with automobile owners. However, the gasoline engine and the Diesel engine, with their new emission-control devices to improve emission performance, have not yet been significantly challenged. A number of manufacturers have introduced hybrid engines, mainly involving
1030-412: A gas as in a Stirling engine , or steam as in a steam engine or an organic liquid such as n-pentane in an Organic Rankine cycle . The fluid can be of any composition; gas is by far the most common, although even single-phase liquid is sometimes used. In the case of the steam engine, the fluid changes phases between liquid and gas. Air-breathing combustion engines are combustion engines that use
1133-548: A given offgas temperature, the NOx level is lowest when excess oxygen is kept lowest. Adherence to these two principles is furthered by making material and heat balances on the combustion process. The material balance directly relates the air/fuel ratio to the percentage of O 2 in the combustion gas. The heat balance relates the heat available for the charge to the overall net heat produced by fuel combustion. Additional material and heat balances can be made to quantify
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#17328008574671236-464: A heat difference to induce high-amplitude sound waves. In general, thermoacoustic engines can be divided into standing wave and travelling wave devices. Stirling engines can be another form of non-combustive heat engine. They use the Stirling thermodynamic cycle to convert heat into work. An example is the alpha type Stirling engine, whereby gas flows, via a recuperator , between a hot cylinder and
1339-425: A heat engine). Chemical heat engines which employ air (ambient atmospheric gas) as a part of the fuel reaction are regarded as airbreathing engines. Chemical heat engines designed to operate outside of Earth's atmosphere (e.g. rockets , deeply submerged submarines ) need to carry an additional fuel component called the oxidizer (although there exist super-oxidizers suitable for use in rockets, such as fluorine ,
1442-463: A hydroperoxide radical (HOO). This reacts further to give hydroperoxides, which break up to give hydroxyl radicals . There are a great variety of these processes that produce fuel radicals and oxidizing radicals. Oxidizing species include singlet oxygen, hydroxyl, monatomic oxygen, and hydroperoxyl . Such intermediates are short-lived and cannot be isolated. However, non-radical intermediates are stable and are produced in incomplete combustion. An example
1545-460: A large scale required efficient electrical generators and electrical distribution networks. To reduce the electric energy consumption from motors and their associated carbon footprints , various regulatory authorities in many countries have introduced and implemented legislation to encourage the manufacture and use of higher efficiency electric motors. A well-designed motor can convert over 90% of its input energy into useful power for decades. When
1648-489: A majority of the models. Several three-cylinder, two-stroke-cycle models were built while most engines had straight or in-line cylinders. There were several V-type models and horizontally opposed two- and four-cylinder makes too. Overhead camshafts were frequently employed. The smaller engines were commonly air-cooled and located at the rear of the vehicle; compression ratios were relatively low. The 1970s and 1980s saw an increased interest in improved fuel economy , which caused
1751-438: A more powerful oxidant than oxygen itself); or the application needs to obtain heat by non-chemical means, such as by means of nuclear reactions . All chemically fueled heat engines emit exhaust gases. The cleanest engines emit water only. Strict zero-emissions generally means zero emissions other than water and water vapour. Only heat engines which combust pure hydrogen (fuel) and pure oxygen (oxidizer) achieve zero-emission by
1854-560: A nuclear power plant uses the heat from the nuclear reaction to produce steam and drive a steam engine, or a gas turbine in a rocket engine may be driven by decomposing hydrogen peroxide . Apart from the different energy source, the engine is often engineered much the same as an internal or external combustion engine. Another group of noncombustive engines includes thermoacoustic heat engines (sometimes called "TA engines") which are thermoacoustic devices that use high-amplitude sound waves to pump heat from one place to another, or conversely use
1957-563: A pressure just above atmospheric to drive the piston helped by a partial vacuum. Improving on the design of the 1712 Newcomen steam engine , the Watt steam engine, developed sporadically from 1763 to 1775, was a great step in the development of the steam engine. Offering a dramatic increase in fuel efficiency , James Watt 's design became synonymous with steam engines, due in no small part to his business partner, Matthew Boulton . It enabled rapid development of efficient semi-automated factories on
2060-564: A previously unimaginable scale in places where waterpower was not available. Later development led to steam locomotives and great expansion of railway transportation . As for internal combustion piston engines , these were tested in France in 1807 by de Rivaz and independently, by the Niépce brothers . They were theoretically advanced by Carnot in 1824. In 1853–57 Eugenio Barsanti and Felice Matteucci invented and patented an engine using
2163-608: A railroad electric locomotive , rather than an electric motor. Some motors are powered by potential or kinetic energy, for example some funiculars , gravity plane and ropeway conveyors have used the energy from moving water or rocks, and some clocks have a weight that falls under gravity. Other forms of potential energy include compressed gases (such as pneumatic motors ), springs ( clockwork motors ) and elastic bands . Historic military siege engines included large catapults , trebuchets , and (to some extent) battering rams were powered by potential energy. A pneumatic motor
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#17328008574672266-544: A redesigned canopy , and was powered by an 800 hp (600 kW; 810 PS) Wright XR-1820-32 radial. The XBT-2 first flew on 25 April 1938, and after successful testing the Navy placed an order for 144 aircraft. In 1939 the aircraft designation was changed to the Douglas SBD-1 with the last 87 on order completed as SBD-2s. By this point, Northrop had become the El Segundo division of Douglas aircraft, hence
2369-569: A return to smaller V-6 and four-cylinder layouts, with as many as five valves per cylinder to improve efficiency. The Bugatti Veyron 16.4 operates with a W16 engine , meaning that two V8 cylinder layouts are positioned next to each other to create the W ;shape sharing the same crankshaft. The largest internal combustion engine ever built is the Wärtsilä-Sulzer RTA96-C , a 14-cylinder, 2-stroke turbocharged diesel engine that
2472-724: A small gasoline engine coupled with an electric motor and with a large battery bank, these are starting to become a popular option because of their environment awareness. Exhaust gas from a spark ignition engine consists of the following: nitrogen 70 to 75% (by volume), water vapor 10 to 12%, carbon dioxide 10 to 13.5%, hydrogen 0.5 to 2%, oxygen 0.2 to 2%, carbon monoxide : 0.1 to 6%, unburnt hydrocarbons and partial oxidation products (e.g. aldehydes ) 0.5 to 1%, nitrogen monoxide 0.01 to 0.4%, nitrous oxide <100 ppm, sulfur dioxide 15 to 60 ppm, traces of other compounds such as fuel additives and lubricants, also halogen and metallic compounds, and other particles. Carbon monoxide
2575-453: A source of water power to provide additional power to watermills and water-raising machines. In the medieval Islamic world , such advances made it possible to mechanize many industrial tasks previously carried out by manual labour . In 1206, al-Jazari employed a crank - conrod system for two of his water-raising machines. A rudimentary steam turbine device was described by Taqi al-Din in 1551 and by Giovanni Branca in 1629. In
2678-429: A strict definition (in practice, one type of rocket engine). If hydrogen is burnt in combination with air (all airbreathing engines), a side reaction occurs between atmospheric oxygen and atmospheric nitrogen resulting in small emissions of NO x . If a hydrocarbon (such as alcohol or gasoline) is burnt as fuel, CO 2 , a greenhouse gas , is emitted. Hydrogen and oxygen from air can be reacted into water by
2781-414: A strong shock wave giving it its characteristic high-pressure peak and high detonation velocity . The act of combustion consists of three relatively distinct but overlapping phases: Efficient process heating requires recovery of the largest possible part of a fuel's heat of combustion into the material being processed. There are many avenues of loss in the operation of a heating process. Typically,
2884-431: A torque include the familiar automobile gasoline and diesel engines, as well as turboshafts . Examples of engines which produce thrust include turbofans and rockets . 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
2987-426: A very low probability. To initiate combustion, energy is required to force dioxygen into a spin-paired state, or singlet oxygen . This intermediate is extremely reactive. The energy is supplied as heat , and the reaction then produces additional heat, which allows it to continue. Combustion of hydrocarbons is thought to be initiated by hydrogen atom abstraction (not proton abstraction) from the fuel to oxygen, to give
3090-445: A vital role in stabilizing the flame in such combustion chambers . Generally, the chemical equation for stoichiometric combustion of a hydrocarbon in oxygen is: For example, the stoichiometric combustion of methane in oxygen is: If the stoichiometric combustion takes place using air as the oxygen source, the nitrogen present in the air ( Atmosphere of Earth ) can be added to the equation (although it does not react) to show
3193-561: A water-powered mill was built in Kaberia of the kingdom of Mithridates during 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, along with systems of gears , or toothed-wheels made of wood and metal to regulate the speed of rotation. More sophisticated small devices, such as
Northrop BT - Misplaced Pages Continue
3296-460: Is acetaldehyde produced in the combustion of ethanol . An intermediate in the combustion of carbon and hydrocarbons, carbon monoxide , is of special importance because it is a poisonous gas , but also economically useful for the production of syngas . Solid and heavy liquid fuels also undergo a great number of pyrolysis reactions that give more easily oxidized, gaseous fuels. These reactions are endothermic and require constant energy input from
3399-454: Is stoichiometric concerning the fuel, where there is no remaining fuel, and ideally, no residual oxidant. Thermodynamically, the chemical equilibrium of combustion in air is overwhelmingly on the side of the products. However, complete combustion is almost impossible to achieve, since the chemical equilibrium is not necessarily reached, or may contain unburnt products such as carbon monoxide , hydrogen and even carbon ( soot or ash). Thus,
3502-400: Is 'low' (i.e., 'micro' in the sense of 'small' and not necessarily a millionth of Earth's normal gravity) such that the influence of buoyancy on physical processes may be considered small relative to other flow processes that would be present at normal gravity. In such an environment, the thermal and flow transport dynamics can behave quite differently than in normal gravity conditions (e.g.,
3605-419: Is 1 / (1 + 2 + 7.54) = 9.49% vol. The stoichiometric combustion reaction for C α H β O γ in air: The stoichiometric combustion reaction for C α H β O γ S δ : The stoichiometric combustion reaction for C α H β O γ N δ S ε : The stoichiometric combustion reaction for C α H β O γ F δ : Various other substances begin to appear in significant amounts in combustion products when
3708-409: Is a high-temperature exothermic redox chemical reaction between a fuel (the reductant) and an oxidant , usually atmospheric oxygen , that produces oxidized, often gaseous products, in a mixture termed as smoke . Combustion does not always result in fire , because a flame is only visible when substances undergoing combustion vaporize, but when it does, a flame is a characteristic indicator of
3811-416: Is a machine that converts potential energy in the form of compressed air into mechanical work . Pneumatic motors generally convert the compressed air to mechanical work through either linear or rotary motion. Linear motion can come from either a diaphragm or piston actuator, while rotary motion is supplied by either a vane type air motor or piston air motor. Pneumatic motors have found widespread success in
3914-463: Is converted to carbon monoxide , and some of the hydrogens remain unreacted. A complete set of equations for the combustion of a hydrocarbon in the air, therefore, requires an additional calculation for the distribution of oxygen between the carbon and hydrogen in the fuel. The amount of air required for complete combustion is known as the "theoretical air" or "stoichiometric air". The amount of air above this value actually needed for optimal combustion
4017-581: Is greatly preferred especially as carbon monoxide is a poisonous gas. When breathed, carbon monoxide takes the place of oxygen and combines with some of the hemoglobin in the blood, rendering it unable to transport oxygen. These oxides combine with water and oxygen in the atmosphere, creating nitric acid and sulfuric acids , which return to Earth's surface as acid deposition, or "acid rain." Acid deposition harms aquatic organisms and kills trees. Due to its formation of certain nutrients that are less available to plants such as calcium and phosphorus, it reduces
4120-532: Is harvested for diverse uses such as cooking , production of electricity or industrial or domestic heating. Combustion is also currently the only reaction used to power rockets . Combustion is also used to destroy ( incinerate ) waste, both nonhazardous and hazardous. Oxidants for combustion have high oxidation potential and include atmospheric or pure oxygen , chlorine , fluorine , chlorine trifluoride , nitrous oxide and nitric acid . For instance, hydrogen burns in chlorine to form hydrogen chloride with
4223-534: Is highly toxic, and can cause carbon monoxide poisoning , so it is important to avoid any build-up of the gas in a confined space. Catalytic converters can reduce toxic emissions, but not eliminate them. Also, resulting greenhouse gas emissions, chiefly carbon dioxide , from the widespread use of engines in the modern industrialized world is contributing to the global greenhouse effect – a primary concern regarding global warming . Some engines convert heat from noncombustive processes into mechanical work, for example
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4326-428: Is known as the "excess air", and can vary from 5% for a natural gas boiler, to 40% for anthracite coal, to 300% for a gas turbine . Incomplete combustion will occur when there is not enough oxygen to allow the fuel to react completely to produce carbon dioxide and water. It also happens when the combustion is quenched by a heat sink, such as a solid surface or flame trap. As is the case with complete combustion, water
4429-710: Is not always practical. Electric motors are ubiquitous, being found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools , and disk drives . They may be powered by direct current (for example a battery powered portable device or motor vehicle), or by alternating current from a central electrical distribution grid. The smallest motors may be found in electric wristwatches. Medium-size motors of highly standardized dimensions and characteristics provide convenient mechanical power for industrial uses. The very largest electric motors are used for propulsion of large ships, and for such purposes as pipeline compressors, with ratings in
4532-438: Is positively correlated with the risk of heart disease. People who survive severe carbon monoxide poisoning may suffer long-term health problems. Carbon monoxide from the air is absorbed in the lungs which then binds with hemoglobin in human's red blood cells. This reduces the capacity of red blood cells that carry oxygen throughout the body. Smoldering is the slow, low-temperature, flameless form of combustion, sustained by
4635-548: Is produced by incomplete combustion; however, carbon and carbon monoxide are produced instead of carbon dioxide. For most fuels, such as diesel oil, coal, or wood, pyrolysis occurs before combustion. In incomplete combustion, products of pyrolysis remain unburnt and contaminate the smoke with noxious particulate matter and gases. Partially oxidized compounds are also a concern; partial oxidation of ethanol can produce harmful acetaldehyde , and carbon can produce toxic carbon monoxide. The designs of combustion devices can improve
4738-428: Is reached with a coolant temperature of around 110 °C (230 °F). Earlier automobile engine development produced a much larger range of engines than is in common use today. Engines have ranged from 1- to 16-cylinder designs with corresponding differences in overall size, weight, engine displacement , and cylinder bores . Four cylinders and power ratings from 19 to 120 hp (14 to 90 kW) were followed in
4841-417: Is the source of oxygen ( O 2 ). In the air, each mole of oxygen is mixed with approximately 3.71 mol of nitrogen. Nitrogen does not take part in combustion, but at high temperatures, some nitrogen will be converted to NO x (mostly NO , with much smaller amounts of NO 2 ). On the other hand, when there is insufficient oxygen to combust the fuel completely, some fuel carbon
4944-510: Is the vapor that burns, not the liquid. Therefore, a liquid will normally catch fire only above a certain temperature: its flash point . The flash point of liquid fuel is the lowest temperature at which it can form an ignitable mix with air. It is the minimum temperature at which there is enough evaporated fuel in the air to start combustion. Combustion of gaseous fuels may occur through one of four distinctive types of burning: diffusion flame , premixed flame , autoignitive reaction front , or as
5047-534: Is then cooled, compressed and reused (closed cycle), or (less commonly) dumped, and cool fluid pulled in (open cycle air engine). " Combustion " refers to burning fuel with an oxidizer , to supply the heat. Engines of similar (or even identical) configuration and operation may use a supply of heat from other sources such as nuclear, solar, geothermal or exothermic reactions not involving combustion; but are not then strictly classed as external combustion engines, but as external thermal engines. The working fluid can be
5150-648: Is theoretically needed to ensure that all the fuel burns. For methane ( CH 4 ) combustion, for example, slightly more than two molecules of oxygen are required. The second principle of combustion management, however, is to not use too much oxygen. The correct amount of oxygen requires three types of measurement: first, active control of air and fuel flow; second, offgas oxygen measurement; and third, measurement of offgas combustibles. For each heating process, there exists an optimum condition of minimal offgas heat loss with acceptable levels of combustibles concentration. Minimizing excess oxygen pays an additional benefit: for
5253-707: The Antikythera Mechanism used complex trains of gears and dials to act as calendars or predict astronomical events. In a poem by Ausonius in the 4th century AD, he mentions a stone-cutting saw powered by water. Hero of Alexandria is credited with many such wind and steam powered machines in the 1st century AD, including the Aeolipile and the vending machine , often these machines were associated with worship, such as animated altars and automated temple doors. Medieval Muslim engineers employed gears in mills and water-raising machines, and used dams as
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#17328008574675356-662: The Volkswagen Beetle , the Citroën 2CV , some Porsche and Subaru cars, many BMW and Honda motorcycles . Opposed four- and six-cylinder engines continue to be used as a power source in small, propeller-driven aircraft . The continued use of internal combustion engines in automobiles is partly due to the improvement of engine control systems, such as on-board computers providing engine management processes, and electronically controlled fuel injection. Forced air induction by turbocharging and supercharging have increased
5459-407: The 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 usually with
5562-733: The combustion of a fuel causes rapid pressurisation of the gaseous combustion products in the combustion chamber, causing them to expand and drive a piston , which turns a crankshaft . Unlike internal combustion engines, a reaction engine (such as a jet engine ) produces thrust by expelling reaction mass , in accordance with Newton's third law of motion . Apart from heat engines, electric motors convert electrical energy into mechanical motion, pneumatic motors use compressed air , and clockwork motors in wind-up toys use elastic energy . In biological systems, molecular motors , like myosins in muscles , use chemical energy to create forces and ultimately motion (a chemical engine, but not
5665-457: The efficiency of a burner during the combustion process. Also, the efficiency of an internal combustion engine can be measured in this way, and some U.S. states and local municipalities use combustion analysis to define and rate the efficiency of vehicles on the road today. Carbon monoxide is one of the products from incomplete combustion . The formation of carbon monoxide produces less heat than formation of carbon dioxide so complete combustion
5768-410: The flame temperature is above about 1600 K . When excess air is used, nitrogen may oxidize to NO and, to a much lesser extent, to NO 2 . CO forms by disproportionation of CO 2 , and H 2 and OH form by disproportionation of H 2 O . For example, when 1 mol of propane is burned with 28.6 mol of air (120% of the stoichiometric amount),
5871-446: The heat-treatment of metals and for gas carburizing . The general reaction equation for incomplete combustion of one mole of a hydrocarbon in oxygen is: When z falls below roughly 50% of the stoichiometric value, CH 4 can become an important combustion product; when z falls below roughly 35% of the stoichiometric value, elemental carbon may become stable. The products of incomplete combustion can be calculated with
5974-399: The oxygen in atmospheric air to oxidise ('burn') the fuel, rather than carrying an oxidiser , as in a rocket . Theoretically, this should result in a better specific impulse than for rocket engines. A continuous stream of air flows through the air-breathing engine. This air is compressed, mixed with fuel, ignited and expelled as the exhaust gas . In reaction engines , the majority of
6077-429: The pistons or turbine blades or a nozzle , and by moving it over a distance, generates mechanical work . An external combustion engine (EC engine) is a heat engine where an internal working fluid is heated by combustion of an external source, through the engine wall or a heat exchanger . The fluid then, by expanding and acting on the mechanism of the engine produces motion and usable work . The fluid
6180-471: The 13th century, the solid rocket motor was invented in China. Driven by gunpowder, this simplest form of internal combustion engine was unable to deliver sustained power, but was useful for propelling weaponry at high speeds towards enemies in battle and for fireworks . After invention, this innovation spread throughout Europe. The Watt steam engine was the first type of steam engine to make use of steam at
6283-641: The BT, the XBT-1 , was equipped with a 750 hp (560 kW; 760 PS) R-1535. This aircraft was followed in 1936 by the BT-1 , powered by an 825 hp (615 kW; 836 PS) R-1535-94 engine. One BT-1 was modified with a fixed tricycle landing gear and was the first such aircraft to land on an aircraft carrier . The final variant, the XBT-2 , was a BT-1 modified to incorporate landing gear which folded laterally into recessed wheel wells, leading edge slots ,
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#17328008574676386-521: The Latin verb moto which means 'to set in motion', or 'maintain motion'. Thus a motor is a device that imparts motion. Motor and engine are interchangeable in standard English. In some engineering jargons, the two words have different meanings, in which engine is a device that burns or otherwise consumes fuel, changing its chemical composition, and a motor is a device driven by electricity , air , or hydraulic pressure, which does not change
6489-815: The Technicolor film Dive Bomber (1941) starring Errol Flynn . Related development Aircraft of comparable role, configuration, and era Related lists Engine Available energy sources include potential energy (e.g. energy of the Earth's gravitational field as exploited in hydroelectric power generation ), heat energy (e.g. geothermal ), chemical energy , electric potential and nuclear energy (from nuclear fission or nuclear fusion ). Many of these processes generate heat as an intermediate energy form; thus heat engines have special importance. Some natural processes, such as atmospheric convection cells convert environmental heat into motion (e.g. in
6592-525: The United States and European Union enforce limits to vehicle nitrogen oxide emissions, which necessitate the use of special catalytic converters or treatment of the exhaust with urea (see Diesel exhaust fluid ). The incomplete (partial) combustion of a hydrocarbon with oxygen produces a gas mixture containing mainly CO 2 , CO , H 2 O , and H 2 . Such gas mixtures are commonly prepared for use as protective atmospheres for
6695-424: The aid of a material balance , together with the assumption that the combustion products reach equilibrium . For example, in the combustion of one mole of propane ( C 3 H 8 ) with four moles of O 2 , seven moles of combustion gas are formed, and z is 80% of the stoichiometric value. The three elemental balance equations are: These three equations are insufficient in themselves to calculate
6798-418: The application of heat. Organic materials undergoing bacterial composting can generate enough heat to reach the point of combustion. Combustion resulting in a turbulent flame is the most used for industrial applications (e.g. gas turbines , gasoline engines , etc.) because the turbulence helps the mixing process between the fuel and oxidizer . The term 'micro' gravity refers to a gravitational state that
6901-587: The change. The U.S. Navy placed an order for 54 BT-1s in 1936 with the aircraft entering service during 1938. BT-1s served on USS Yorktown and Enterprise . The type was not a success in service due to poor handling characteristics, especially at low speeds, "a fatal flaw in a carrier based aircraft." It was also prone to unexpected rolls and a number of aircraft were lost in crashes. Data from United States Navy Aircraft since 1911 General characteristics Performance Armament Northrop BT-1s appeared in pre-war yellow wing paint schemes in
7004-436: The chemical composition of its energy source. However, rocketry uses the term rocket motor , even though they consume fuel. A heat engine may also serve as a prime mover —a component that transforms the flow or changes in pressure of a fluid into mechanical energy . An automobile powered by an internal combustion engine may make use of various motors and pumps, but ultimately all such devices derive their power from
7107-447: The combustion energy (heat) exits the engine as exhaust gas, which provides thrust directly. Typical air-breathing engines include: The operation of engines typically has a negative impact upon air quality and ambient sound levels . There has been a growing emphasis on the pollution producing features of automotive power systems. This has created new interest in alternate power sources and internal-combustion engine refinements. Though
7210-408: The combustion gas composition. However, at the equilibrium position, the water-gas shift reaction gives another equation: For example, at 1200 K the value of K eq is 0.728. Solving, the combustion gas consists of 42.4% H 2 O , 29.0% CO 2 , 14.7% H 2 , and 13.9% CO . Carbon becomes a stable phase at 1200 K and 1 atm pressure when z is less than 30% of
7313-457: The combustion products contain 3.3% O 2 . At 1400 K , the equilibrium combustion products contain 0.03% NO and 0.002% OH . At 1800 K , the combustion products contain 0.17% NO , 0.05% OH , 0.01% CO , and 0.004% H 2 . Diesel engines are run with an excess of oxygen to combust small particles that tend to form with only a stoichiometric amount of oxygen, necessarily producing nitrogen oxide emissions. Both
7416-400: The dominant loss is sensible heat leaving with the offgas (i.e., the flue gas ). The temperature and quantity of offgas indicates its heat content ( enthalpy ), so keeping its quantity low minimizes heat loss. In a perfect furnace, the combustion air flow would be matched to the fuel flow to give each fuel molecule the exact amount of oxygen needed to cause complete combustion. However, in
7519-489: The efficiency of a motor is raised by even a few percentage points, the savings, in kilowatt hours (and therefore in cost), are enormous. The electrical energy efficiency of a typical industrial induction motor can be improved by: 1) reducing the electrical losses in the stator windings (e.g., by increasing the cross-sectional area of the conductor , improving the winding technique, and using materials with higher electrical conductivities , such as copper ), 2) reducing
7622-496: The electrical losses in the rotor coil or casting (e.g., by using materials with higher electrical conductivities, such as copper), 3) reducing magnetic losses by using better quality magnetic steel , 4) improving the aerodynamics of motors to reduce mechanical windage losses, 5) improving bearings to reduce friction losses , and 6) minimizing manufacturing tolerances . For further discussion on this subject, see Premium efficiency ). By convention, electric engine refers to
7725-404: The engine. Another way of looking at it is that a motor receives power from an external source, and then converts it into mechanical energy, while an engine creates power from pressure (derived directly from the explosive force of combustion or other chemical reaction, or secondarily from the action of some such force on other substances such as air, water, or steam). Simple machines , such as
7828-636: The first half of the 20th century, a trend of increasing engine power occurred, particularly in the U.S. models. Design changes incorporated all known methods of increasing engine capacity, including increasing the pressure in the cylinders to improve efficiency, increasing the size of the engine, and increasing the rate at which the engine produces work. The higher forces and pressures created by these changes created engine vibration and size problems that led to stiffer, more compact engines with V and opposed cylinder layouts replacing longer straight-line arrangements. Optimal combustion efficiency in passenger vehicles
7931-691: The forces multiplied and the speed reduced . These were used in cranes and aboard ships in Ancient Greece , as well as 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 more ancient. By the 1st century AD, cattle and horses were used in mills , driving machines similar to those powered by humans in earlier times. According to Strabo ,
8034-403: The form of rising air currents). Mechanical energy is of particular importance in transportation , but also plays a role in many industrial processes such as cutting, grinding, crushing, and mixing. Mechanical heat engines convert heat into work via various thermodynamic processes. The internal combustion engine is perhaps the most common example of a mechanical heat engine in which heat from
8137-528: The free-piston principle that was possibly the first 4-cycle engine. The invention of an internal combustion engine which was later commercially successful was made during 1860 by Etienne Lenoir . In 1877, the Otto cycle was capable of giving a far higher power-to-weight ratio than steam engines and worked much better for many transportation applications such as cars and aircraft. The first commercially successful automobile, created by Karl Benz , added to
8240-442: The hand-held tool industry and continual attempts are being made to expand their use to the transportation industry. However, pneumatic motors must overcome efficiency deficiencies before being seen as a viable option in the transportation industry. A hydraulic motor derives its power from a pressurized liquid . This type of engine is used to move heavy loads and drive machinery. Combustion Combustion , or burning ,
8343-486: The heat evolved when oxygen directly attacks the surface of a condensed-phase fuel. It is a typically incomplete combustion reaction. Solid materials that can sustain a smoldering reaction include coal, cellulose , wood , cotton , tobacco , peat , duff , humus , synthetic foams, charring polymers (including polyurethane foam ) and dust . Common examples of smoldering phenomena are the initiation of residential fires on upholstered furniture by weak heat sources (e.g.,
8446-411: The heat of a combustion process. The internal combustion engine is an engine in which the combustion of a fuel (generally, fossil fuel ) occurs with an oxidizer (usually air) in a combustion chamber . In an internal combustion engine the expansion of the high temperature and high pressure gases, which are produced by the combustion, directly applies force to components of the engine, such as
8549-536: The heat required to produce more of them. Combustion is often hot enough that incandescent light in the form of either glowing or a flame is produced. A simple example can be seen in the combustion of hydrogen and oxygen into water vapor , a reaction which is commonly used to fuel rocket engines . This reaction releases 242 kJ/mol of heat and reduces the enthalpy accordingly (at constant temperature and pressure): Uncatalyzed combustion in air requires relatively high temperatures. Complete combustion
8652-439: The initial version began in 1935. It was powered by a 700 hp (520 kW; 710 PS) Pratt and Whitney XR-1535-66 double row air-cooled radial engine and had hydraulically actuated perforated split flaps ( dive brakes ), and main landing gear that retracted backwards into fairing "trousers" beneath the wings. The perforated flaps were invented to eliminate tail buffeting during diving maneuvers. The next iteration of
8755-462: The interest in light and powerful engines. The lightweight gasoline internal combustion engine, operating on a four-stroke Otto cycle, has been the most successful for light automobiles, while the thermally more-efficient Diesel engine is used for trucks and buses. However, in recent years, turbocharged Diesel engines have become increasingly popular in automobiles, especially outside of the United States, even for quite small cars. In 1896, Karl Benz
8858-402: The liberation of heat and light characteristic of combustion. Although usually not catalyzed, combustion can be catalyzed by platinum or vanadium , as in the contact process . In complete combustion, the reactant burns in oxygen and produces a limited number of products. When a hydrocarbon burns in oxygen, the reaction will primarily yield carbon dioxide and water. When elements are burned,
8961-420: The maximum degree of oxidation, and it can be temperature-dependent. For example, sulfur trioxide is not produced quantitatively by the combustion of sulfur. NO x species appear in significant amounts above about 2,800 °F (1,540 °C), and more is produced at higher temperatures. The amount of NO x is also a function of oxygen excess. In most industrial applications and in fires , air
9064-649: The power output of smaller displacement engines that are lighter in weight and more fuel-efficient at normal cruise power.. Similar changes have been applied to smaller Diesel engines, giving them almost the same performance characteristics as gasoline engines. This is especially evident with the popularity of smaller diesel engine-propelled cars in Europe. Diesel engines produce lower hydrocarbon and CO 2 emissions, but greater particulate and NO x pollution, than gasoline engines. Diesel engines are also 40% more fuel efficient than comparable gasoline engines. In
9167-576: The produced smoke is usually toxic and contains unburned or partially oxidized products. Any combustion at high temperatures in atmospheric air , which is 78 percent nitrogen , will also create small amounts of several nitrogen oxides , commonly referred to as NOx , since the combustion of nitrogen is thermodynamically favored at high, but not low temperatures. Since burning is rarely clean, fuel gas cleaning or catalytic converters may be required by law. Fires occur naturally, ignited by lightning strikes or by volcanic products. Combustion ( fire )
9270-463: The productivity of the ecosystem and farms. An additional problem associated with nitrogen oxides is that they, along with hydrocarbon pollutants, contribute to the formation of ground level ozone , a major component of smog. Breathing carbon monoxide causes headache, dizziness, vomiting, and nausea. If carbon monoxide levels are high enough, humans become unconscious or die. Exposure to moderate and high levels of carbon monoxide over long periods
9373-425: The products are primarily the most common oxides. Carbon will yield carbon dioxide , sulfur will yield sulfur dioxide , and iron will yield iron(III) oxide . Nitrogen is not considered to be a combustible substance when oxygen is the oxidant . Still, small amounts of various nitrogen oxides (commonly designated NO x species) form when the air is the oxidative. Combustion is not necessarily favorable to
9476-644: The quality of combustion, such as burners and internal combustion engines . Further improvements are achievable by catalytic after-burning devices (such as catalytic converters ) or by the simple partial return of the exhaust gases into the combustion process. Such devices are required by environmental legislation for cars in most countries. They may be necessary to enable large combustion devices, such as thermal power stations , to reach legal emission standards . The degree of combustion can be measured and analyzed with test equipment. HVAC contractors, firefighters and engineers use combustion analyzers to test
9579-488: The reaction. While activation energy must be supplied to initiate combustion (e.g., using a lit match to light a fire), the heat from a flame may provide enough energy to make the reaction self-sustaining. The study of combustion is known as combustion science . Combustion is often a complicated sequence of elementary radical reactions . Solid fuels , such as wood and coal , first undergo endothermic pyrolysis to produce gaseous fuels whose combustion then supplies
9682-422: The real world, combustion does not proceed in a perfect manner. Unburned fuel (usually CO and H 2 ) discharged from the system represents a heating value loss (as well as a safety hazard). Since combustibles are undesirable in the offgas, while the presence of unreacted oxygen there presents minimal safety and environmental concerns, the first principle of combustion management is to provide more oxygen than
9785-499: The stoichiometric composition of the fuel in air and the composition of the resultant flue gas. Treating all non-oxygen components in air as nitrogen gives a 'nitrogen' to oxygen ratio of 3.77, i.e. (100% − O 2 %) / O 2 % where O 2 % is 20.95% vol: where z = x + y 4 {\displaystyle z=x+{y \over 4}} . For example, the stoichiometric combustion of methane in air is: The stoichiometric composition of methane in air
9888-414: The stoichiometric value, at which point the combustion products contain more than 98% H 2 and CO and about 0.5% CH 4 . Substances or materials which undergo combustion are called fuels . The most common examples are natural gas, propane, kerosene , diesel , petrol, charcoal, coal, wood, etc. Combustion of a liquid fuel in an oxidizing atmosphere actually happens in the gas phase. It
9991-404: The thermal advantage from preheating the combustion air, or enriching it in oxygen. Combustion in oxygen is a chain reaction in which many distinct radical intermediates participate. The high energy required for initiation is explained by the unusual structure of the dioxygen molecule. The lowest-energy configuration of the dioxygen molecule is a stable, relatively unreactive diradical in
10094-442: The thousands of kilowatts . Electric motors may be classified by the source of electric power, by their internal construction, and by their application. The physical principle of production of mechanical force by the interactions of an electric current and a magnetic field was known as early as 1821. Electric motors of increasing efficiency were constructed throughout the 19th century, but commercial exploitation of electric motors on
10197-523: Was designed to power the Emma Mærsk , the largest container ship in the world when launched in 2006. This engine has a mass of 2,300 tonnes, and when running at 102 rpm (1.7 Hz) produces over 80 MW, and can use up to 250 tonnes of fuel per day. An engine can be put into a category according to two criteria: the form of energy it accepts in order to create motion, and the type of motion it outputs. Combustion engines are heat engines driven by
10300-436: Was granted a patent for his design of the first engine with horizontally opposed pistons. 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 momentum. Engines of this design are often referred to as “flat” or “boxer” engines due to their shape and low profile. They were used in
10403-463: Was merely a water pump, with the engine being transported to the fire by horses. 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
10506-473: 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
10609-456: Was the first controlled chemical reaction discovered by humans, in the form of campfires and bonfires , and continues to be the main method to produce energy for humanity. Usually, the fuel is carbon , hydrocarbons , or more complicated mixtures such as wood that contain partially oxidized hydrocarbons. The thermal energy produced from the combustion of either fossil fuels such as coal or oil , or from renewable fuels such as firewood ,
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