Engine

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Animation showing the four stages of the four-stroke gasoline combustion engine cycle:
Induction (Fuel enters)
Compression
Ignition (Fuel is burnt)
Emission (Exhaust out) 4StrokeEngine Ortho 3D Small.gif
Animation showing the four stages of the four-stroke gasoline combustion engine cycle:
  1. Induction (Fuel enters)
  2. Compression
  3. Ignition (Fuel is burnt)
  4. Emission (Exhaust out)

An engine or motor is a machine designed to convert one form of energy into mechanical energy. [1] [2] Heat engines, like the internal combustion engine, burn a fuel to create heat which is then used to do work. 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.

Contents

Terminology

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. [3]

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. [4] 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.

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.

Motor and engine are interchangeable in standard English. [5] 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 the chemical composition of its energy source. [6] [7] 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. [8] 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 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). [9]

History

Antiquity

Simple machines, such as 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 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, 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 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

Medieval Muslim engineers employed gears in mills and water-raising machines, and used dams as a source of water power to provide additional power to watermills and water-raising machines. [10] 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 [11] in 1551 and by Giovanni Branca [12] in 1629. [13]

In 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.

Industrial Revolution

Boulton & Watt engine of 1788 Boulton and Watt centrifugal governor-MJ.jpg
Boulton & Watt engine of 1788

The Watt steam engine was the first type of steam engine to make use of steam at 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 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.[ citation needed ] In 1853–57 Eugenio Barsanti and Felice Matteucci invented and patented an engine using the free-piston principle that was possibly the first 4-cycle engine. [14]

The invention of an internal combustion engine which was later commercially successful was made during 1860 by Etienne Lenoir. [15]

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.

A V6 internal combustion engine from a Mercedes-Benz Mercedes V6 DTM Rennmotor 1996.jpg
A V6 internal combustion engine from a Mercedes-Benz

Automobiles

The first commercially successful automobile, created by Karl Benz, added to 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 more efficient Diesel engine is used for trucks and buses. However, in recent years, turbo Diesel engines have become increasingly popular, especially outside of the United States, even for quite small cars.

Horizontally opposed pistons

In 1896, Karl Benz 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 engines because of their shape and lower profile. They were used in the Volkswagen Beetle, the Citroën 2CV, some Porsche and Subaru cars, many BMW and Honda motorcycles, and propeller aircraft engines.

Advancement

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 engine efficiencies. Similar changes have been applied to smaller diesel engines giving them almost the same power characteristics as gasoline 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, although they require special machining not available in most factories. Diesel engines produce lower hydrocarbon and CO
2
emissions, but greater particulate and NO
x
pollution, than gasoline engines. [16] Diesel engines are also 40% more fuel efficient than comparable gasoline engines. [16]

Increasing power

In the first half of the 20th century, a trend of increasing engine power occurred, particularly in the U.S models.[ clarification needed ] 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.

Combustion efficiency

The design principles favoured in Europe, because of economic and other restraints such as smaller and twistier roads, leant toward smaller cars and corresponding to the design principles that concentrated on increasing the combustion efficiency of smaller engines. This produced more economical engines with earlier four-cylinder designs rated at 40 horsepower (30 kW) and six-cylinder designs rated as low as 80 horsepower (60 kW), compared with the large volume V-8 American engines with power ratings in the range from 250 to 350 hp, some even over 400 hp (190 to 260 kW).[ clarification needed ][ citation needed ]

Engine configuration

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 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 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 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.

Types

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.

Heat engine

Combustion engine

Combustion engines are heat engines driven by the heat of a combustion process.

Internal combustion engine

A three-horsepower internal combustion engine that ran on coal gas A three-horsepower internal combustion engine that ran on coal gas LCCN2006691790.jpg
A three-horsepower internal combustion engine that ran on coal gas

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 the pistons or turbine blades or a nozzle, and by moving it over a distance, generates mechanical work. [17] [18] [19] [20]

External combustion engine

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. [21] The fluid 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 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

Air-breathing combustion engines are combustion engines that use 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.

Examples

Typical air-breathing engines include:

airbreathing jet engine
Turbo-propeller engine

Environmental effects

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 a few limited-production battery-powered electric vehicles have appeared, they have not proved competitive owing to costs and operating characteristics.[ citation needed ] 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.[ citation needed ] A number of manufacturers have introduced hybrid engines, mainly involving a small gasoline engine coupled with an electric motor and with a large battery bank, but these too have yet to make much of an inroad into the market shares of gasoline and Diesel engines.

Air quality

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. [22] Carbon monoxide 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 completely 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.

Non-combusting heat engines

Some engines convert heat from noncombustive processes into mechanical work, for example 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 which use high-amplitude sound waves to pump heat from one place to another, or conversely use a heat difference to induce high-amplitude sound waves. In general, thermoacoustic engines can be divided into standing wave and travelling wave devices. [23]

Non-thermal chemically powered motor

Non-thermal motors usually are powered by a chemical reaction, but are not heat engines. Examples include:

Electric motor

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 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 the thousands of kilowatts. Electric motors may be classified by the source of electric power, by their internal construction, and by their application.

Electric motor Electric motor.gif
Electric motor

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 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. [24] When 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 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 a railroad electric locomotive, rather than an electric motor.

Physically powered 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.

Pneumatic motor

A pneumatic motor 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 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.

Hydraulic motor

A hydraulic motor derives its power from a pressurized liquid. This type of engine is used to move heavy loads and drive machinery. [25]

Performance

The following are used in the assessment of the performance of an engine.

Speed

Speed refers to crankshaft rotation in piston engines and the speed of compressor/turbine rotors and electric motor rotors. It is measured in revolutions per minute (RPM).

Thrust

Thrust is the force exerted on an aircraft engine or its propeller after it has speeded up the air passing through it.

Torque

Torque is a turning moment on a shaft and is calculated by multiplying the force causing the moment by its distance from the shaft.

Power

Power is the measure of how fast work is done.

Efficiency

Efficiency is a measure of how much fuel is wasted in producing power.

Sound levels

Vehicle noise is predominantly from the engine at low vehicle speeds and from tires and the air flowing past the vehicle at higher speeds. [26] Electric motors are quieter than internal combustion engines. Thrust-producing engines, such as turbofans, turbojets and rockets emit the greatest amount of noise due to the way their thrust-producing, high-velocity exhaust streams interact with the surrounding stationary air. Noise reduction technology includes intake and exhaust system mufflers (silencers) on gasoline and diesel engines and noise attenuation liners in turbofan inlets.

Engines by use

Particularly notable kinds of engines include:

See also

Notes

  1. "Motor". Dictionary.reference.com. Retrieved 2011-05-09. a person or thing that imparts motion, esp. a contrivance, as a steam engine, that receives and modifies energy from some source in order to utilize it in driving machinery.
  2. Dictionary.com: (World heritage) "3. any device that converts another form of energy into mechanical energy so as to produce motion"
  3. "World Wide Words: Engine and Motor". World Wide Words. Retrieved 2020-04-30.
  4. "Engine". Collins English Dictionary. Retrieved 2012-09-03.
  5. Dictionary definitions:
  6. "Engine", McGraw-Hill Concise Encyclopedia of Science and Technology, Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc., 1994, p. 714.
  7. Quinion, Michael. "World Wide Words: Engine and Motor". Worldwide Words. Retrieved 2018-02-03.
  8. "Prime mover", McGraw-Hill Concise Encyclopedia of Science and Technology, Third Edition, Sybil P. Parker, ed. McGraw-Hill, Inc., 1994, p. 1498.
  9. Press, AIP, Associated (2007). Stylebook and Briefing on Media Law (42nd ed.). New York: Basic Books. p. 84. ISBN   978-0-465-00489-8.
  10. Hassan, Ahmad Y. Transmission Of Islamic Engineering. Transfer Of Islamic Technology To The West, Part II. Archived from the original on 2008-02-18.
  11. Hassan, Ahmad Y. (1976). Taqi al-Din and Arabic Mechanical Engineering, pp. 34–35. Institute for the History of Arabic Science, University of Aleppo.
  12. "University of Rochester, NY, The growth of the steam engine online history resource, chapter one". History.rochester.edu. Archived from the original on 2012-02-04. Retrieved 2010-02-03.
  13. " Power plant engineering ". P.K. Nag (2002). Tata McGraw-Hill. p. 432. ISBN   0-07-043599-5
  14. "La documentazione essenziale per l'attribuzione della scoperta". A later request was presented to the Patent Office of the Reign of Piedmont, under No. 700 of Volume VII of that Office. The text of this patent request is not available, only a photo of the table containing a drawing of the engine. This may have been either a new patent or an extension of a patent granted three days earlier, on 30 December 1857, at Turin.
  15. Victor Albert Walter Hillier, Peter Coombes – Hillier's Fundamentals of Motor Vehicle Technology, Book 1 Nelson Thornes, 2004 ISBN   0-7487-8082-3 [Retrieved 2016-06-16]
  16. 1 2 Harrison, Roy M. (2001), Pollution: Causes, Effects and Control (4th ed.), Royal Society of Chemistry, ISBN   978-0-85404-621-8
  17. Proctor II, Charles Lafayette. "Internal Combustion engines". Encyclopædia Britannica Online. Retrieved 2011-05-09.
  18. "Internal combustion engine". Answers.com. Retrieved 2011-05-09.
  19. "Columbia encyclopedia: Internal combustion engine". Inventors.about.com. Archived from the original on 2012-07-21. Retrieved 2011-05-09.
  20. "Internal-combustion engine". Infoplease.com. 2007. Retrieved 2011-05-09.
  21. "External combustion". Merriam-Webster Online Dictionary. 2010-08-13. Retrieved 2011-05-09.
  22. Paul Degobert, Society of Automotive Engineers (1995), Automobiles and Pollution
  23. Emam, Mahmoud (2013). Experimental Investigations on a Standing-Wave Thermoacoustic Engine, M.Sc. Thesis. Egypt: Cairo University. Retrieved 2013-09-26.
  24. "Motors". American Council for an Energy-Efficient Economy. http://www.aceee.org/topics/motors
  25. "Howstuffworks "Engineering"". Reference.howstuffworks.com. 2006-01-29. Archived from the original on 2009-08-21. Retrieved 2011-05-09.
  26. Hogan, C. Michael (September 1973). "Analysis of Highway Noise". Journal of Water, Air, and Soil Pollution. 2 (3): 387–92. Bibcode:1973WASP....2..387H. doi:10.1007/BF00159677. ISSN   0049-6979.

Related Research Articles

Reciprocating engine Engine utilising one or more reciprocating pistons.

A reciprocating engine, also often known as a piston engine, is typically a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types. The main types are: the internal combustion engine, used extensively in motor vehicles; the steam engine, the mainstay of the Industrial Revolution; and the niche application Stirling engine. Internal combustion engines are further classified in two ways: either a spark-ignition (SI) engine, where the spark plug initiates the combustion; or a compression-ignition (CI) engine, where the air within the cylinder is compressed, thus heating it, so that the heated air ignites fuel that is injected then or earlier.

Timeline of motor and engine technology

Petrol engine Internal combustion engine designed to run on gasoline

Petrol engine or gasoline engine is an internal combustion engine with spark-ignition, designed to run on petrol (gasoline) and similar volatile fuels.

Four-stroke engine Internal combustion engine type

A four-strokeengine is an internal combustion (IC) engine in which the piston completes four separate strokes while turning the crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed:

  1. Intake: Also known as induction or suction. This stroke of the piston begins at top dead center (T.D.C.) and ends at bottom dead center (B.D.C.). In this stroke the intake valve must be in the open position while the piston pulls an air-fuel mixture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. The piston is moving down as air is being sucked in by the downward motion against the piston.
  2. Compression: This stroke begins at B.D.C, or just at the end of the suction stroke, and ends at T.D.C. In this stroke the piston compresses the air-fuel mixture in preparation for ignition during the power stroke (below). Both the intake and exhaust valves are closed during this stage.
  3. Combustion: Also known as power or ignition. This is the start of the second revolution of the four stroke cycle. At this point the crankshaft has completed a full 360 degree revolution. While the piston is at T.D.C. the compressed air-fuel mixture is ignited by a spark plug or by heat generated by high compression, forcefully returning the piston to B.D.C. This stroke produces mechanical work from the engine to turn the crankshaft.
  4. Exhaust: Also known as outlet. During the exhaust stroke, the piston, once again, returns from B.D.C. to T.D.C. while the exhaust valve is open. This action expels the spent air-fuel mixture through the exhaust valve.
Stirling engine Engine powered by a source of heat applied externally to it.

A Stirling engine is a heat engine that is operated by a cyclic compression and expansion of air or other gas at different temperatures, resulting in a net conversion of heat energy to mechanical work. More specifically, the Stirling engine is a closed-cycle regenerative heat engine with a permanent gaseous working fluid. Closed-cycle, in this context, means a thermodynamic system in which the working fluid is permanently contained within the system, and regenerative describes the use of a specific type of internal heat exchanger and thermal store, known as the regenerator. Strictly speaking, the inclusion of the regenerator is what differentiates a Stirling engine from other closed cycle hot air engines.

Fuel efficiency is a form of thermal efficiency, meaning the ratio of effort to result of a process that converts chemical potential energy contained in a carrier (fuel) into kinetic energy or work. Overall fuel efficiency may vary per device, which in turn may vary per application, and this spectrum of variance is often illustrated as a continuous energy profile. Non-transportation applications, such as industry, benefit from increased fuel efficiency, especially fossil fuel power plants or industries dealing with combustion, such as ammonia production during the Haber process.

Brayton cycle Thermodynamic cycle

The Brayton cycle is a thermodynamic cycle named after George Brayton that describes the workings of a constant-pressure heat engine. The original Brayton engines used a piston compressor and piston expander, but more modern gas turbine engines and airbreathing jet engines also follow the Brayton cycle. Although the cycle is usually run as an open system, it is conventionally assumed for the purposes of thermodynamic analysis that the exhaust gases are reused in the intake, enabling analysis as a closed system.

A combustion chamber is that part of an internal combustion engine in which the fuel/air mix is burned. For steam engines, the term has also been used for an extension of the firebox which is used to allow a more complete combustion process.

Gas engine internal combustion engine powered by natural gas

A gas engine is an internal combustion engine that runs on a gaseous fuel, such as coal gas, producer gas, biogas, landfill gas or natural gas. In the United Kingdom, the term is unambiguous. In the United States, due to the widespread use of "gas" as an abbreviation for gasoline (petrol), such an engine might also be called a gaseous-fueled engine or natural gas engine or spark ignited.

Hydrolock Malfunction of a gas compression mechanism when it acts on a liquid

Hydrolock is an abnormal condition of any device which is designed to compress a gas by mechanically restraining it; most commonly the reciprocating internal combustion engine, the case this article refers to unless otherwise noted. Hydrolock occurs when a volume of liquid greater than the volume of the cylinder at its minimum enters the cylinder. Since liquids are nearly incompressible the piston cannot complete its travel; either the engine must stop rotating or a mechanical failure must occur.

Automotive engine car and truck technology

As of 2013, there were a wide variety of propulsion systems available or potentially available for automobiles and other vehicles. Options included internal combustion engines fueled by petrol, diesel, propane, or natural gas; hybrid vehicles, plug-in hybrids, fuel cell vehicles fueled by hydrogen and all electric cars. Fueled vehicles seem to have the advantage due to the limited range and high cost of batteries. Some options required construction of a network of fueling or charging stations. With no compelling advantage for any particular option car makers pursued parallel development tracks using a variety of options. Reducing the weight of vehicles was one strategy being employed.

Thermal efficiency performance measure of a device that uses thermal energy

In thermodynamics, the thermal efficiency is a dimensionless performance measure of a device that uses thermal energy, such as an internal combustion engine, a steam turbine or a steam engine, a boiler, furnace, or a refrigerator for example. For a heat engine, thermal efficiency is the fraction of the energy added by heat that is converted to net work output. In the case of a refrigeration or heat pump cycle, thermal efficiency is the ratio of net heat output for heating, or removal for cooling, to energy input.

Timeline of heat engine technology

This Timeline of heat engine technology describes how heat engines have been known since antiquity but have been made into increasingly useful devices since the 17th century as a better understanding of the processes involved was gained. They continue to be developed today.

Hot-bulb engine

The hot-bulb engine is a type of internal combustion engine in which fuel ignites by coming in contact with a red-hot metal surface inside a bulb, followed by the introduction of air (oxygen) compressed into the hot-bulb chamber by the rising piston. There is some ignition when the fuel is introduced, but it quickly uses up the available oxygen in the bulb. Vigorous ignition takes place only when sufficient oxygen is supplied to the hot-bulb chamber on the compression stroke of the engine.

Engine efficiency of thermal engines is the relationship between the total energy contained in the fuel, and the amount of energy used to perform useful work. There are two classifications of thermal engines-

  1. Internal combustion and
  2. External combustion engines.

The term six-stroke engine has been applied to a number of alternative internal combustion engine designs that attempt to improve on traditional two-stroke and four-stroke engines. Claimed advantages may include increased fuel efficiency, reduced mechanical complexity and/or reduced emissions. These engines can be divided into two groups based on the number of pistons that contribute to the six strokes.

Free-piston engine

A free-piston engine is a linear, 'crankless' internal combustion engine, in which the piston motion is not controlled by a crankshaft but determined by the interaction of forces from the combustion chamber gases, a rebound device and a load device.

History of the internal combustion engine aspect of history

Various scientists and engineers contributed to the development of internal combustion engines. In 1791, John Barber developed a turbine. In 1794 Thomas Mead patented a gas engine. Also in 1794 Robert Street patented an internal-combustion engine, which was also the first to use the liquid fuel (petroleum) and built an engine around that time. In 1798, John Stevens designed the first American internal combustion engine. In 1807, French engineers Nicéphore and Claude Niépce ran a prototype internal combustion engine, using controlled dust explosions, the Pyréolophore. This engine powered a boat on the Saône river, France. The same year, the Swiss engineer François Isaac de Rivaz built and patented a hydrogen and oxygen powered internal-combustion engine. The fuel was stored in a balloon and the spark was electrically ignited by a hand-operated trigger. Fitted to a crude four-wheeled wagon, François Isaac de Rivaz first drove it 100 meters in 1813, thus making history as the first car-like vehicle known to have been powered by an internal-combustion engine. In 1823, Samuel Brown patented the first internal combustion engine to be applied industrially in the U.S., one of his engines pumped water on the Croydon Canal from 1830 to 1836. He also demonstrated a boat using his engine on the Thames in 1827, and an engine-driven carriage in 1828. Father Eugenio Barsanti, an Italian engineer, together with Felice Matteucci of Florence invented the first real internal combustion engine in 1853. Their patent request was granted in London on June 12, 1854, and published in London's Morning Journal under the title "Specification of Eugene Barsanti and Felix Matteucci, Obtaining Motive Power by the Explosion of Gasses". In 1860, Belgian Jean Joseph Etienne Lenoir produced a gas-fired internal combustion engine. In 1864, Nicolaus Otto patented the first atmospheric gas engine. In 1872, American George Brayton invented the first commercial liquid-fueled internal combustion engine. In 1876, Nicolaus Otto, working with Gottlieb Daimler and Wilhelm Maybach, patented the compressed charge, four-stroke cycle engine. In 1879, Karl Benz patented a reliable two-stroke gas engine. In 1892, Rudolf Diesel developed the first compressed charge, a compression ignition engine. In 1926, Robert Goddard launched the first liquid-fueled rocket. In 1939, the Heinkel He 178 became the world's first jet aircraft. In 1954 German engineer Felix Wankel patented a "pistonless" engine using an eccentric rotary design.

Internal combustion engines come in a wide variety of types, but have certain family resemblances, and thus share many common types of components.

Internal combustion engine Engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber

An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, the expansion of the high-temperature and high-pressure gases produced by combustion applies direct force to some component of the engine. The force is applied typically to pistons, turbine blades, rotor or a nozzle. This force moves the component over a distance, transforming chemical energy into useful work.

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