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A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. The mechanical output is called work, and the thermal energy input is called heat. Heat engines typically run on a specific thermodynamic cycle. Heat engines are often named after the thermodynamic cycle they are modeled by. They often pick up alternate names, such as gasoline/petrol, turbine, or steam engines. Heat engines can generate heat inside the engine itself or it can absorb heat from an external source. Heat engines can be open to the atmospheric air or sealed and closed off to the outside (Open or closed cycle). Image File history File links Portal. ... 1. ... In physics, mechanical work is the amount of energy transferred by a force. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... A thermodynamic cycle is a series of thermodynamic processes which returns a system to its initial state. ...

In engineering and thermodynamics, a heat engine performs the conversion of heat energy to mechanical work by exploiting the temperature gradient between a hot "source" and a cold "sink". Heat is transferred from the source, through the "working body" of the engine, to the sink, and in this process some of the heat is converted into work by exploiting the properties of a working substance (usually a gas or liquid). Engineering is the applied science of acquiring and applying knowledge to design, analysis, and/or construction of works for practical purposes. ... Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dunamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... In physics, mechanical work is the amount of energy transferred by a force. ... Fig. ... This article does not cite any references or sources. ... In thermal physics, heat transfer is the passage of thermal energy from a hot to a cold body. ... In thermodynamics, a thermodynamic system is defined as that part of the universe that is under consideration. ... Lightning is the electric breakdown of air by strong electric fields, or a plasma, which causes an energy transfer from the electric field to heat, mechanical energy (the random motion of air molecules caused by the heat), and light. ...

Figure 1: Heat engine diagram

Image File history File links Carnot_heat_engine_2. ... Image File history File links Carnot_heat_engine_2. ...

Overview

Heat engines are often confused with the cycles they attempt to mimic. Typically when describing the physical device the term 'engine' is used. When describing the model the term 'cycle' is used.

In thermodynamics, heat engines are often modeled using a standard engineering model such as the Otto cycle (4-stroke/2-stroke). Actual data from an operating engine, one is called an indicator diagram, is used to refine the model. All modern implementations of heat engines do not exactly match the thermodynamic cycle they are modeled by. One could say that the thermodynamic cycle is an ideal case of the mechanical engine. One could equally say that the model doesn't quite perfectly match the mechanical engine. However, understanding is gained from the simplified models, and ideal cases they may represent. Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dunamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today ( cars and trucks, generators, etc). ... In the technology of the steam engine, the indicator diagram was a device developed by James Watt and his employee John Southern to improve the efficiency of engines. ...

In general terms, the larger the difference in temperature between the hot source and the cold sink, the larger is the potential thermal efficiency of the cycle. On Earth, the cold side of any heat engine is limited to close to the ambient temperature of the environment, or not much lower than 300 kelvins, so most efforts to improve the thermodynamic efficiencies of various heat engines focus on increasing the temperature of the source, within material limits. The thermal efficiency () is a dimensionless performance measure of a thermal device such as an internal combustion engine, a boiler, or a furnace, for example. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...

The efficiency of various heat engines proposed or used today ranges from 3 percent ^[1](97 percent waste heat) for the OTEC ocean power proposal through 25 percent for most automotive engines, to 45 percent for a supercritical coal plant, to about 60 percent for a steam-cooled combined cycle gas turbine. All of these processes gain their efficiency (or lack thereof) due to the temperature drop across them. This article or section does not cite any references or sources. ... Mohave Generating Station, a 1,580 MW coal power plant near Laughlin, Nevada A fossil fuel power plant is an energy conversion center that combusts fossil fuels to produce electricity, designed on a large scale for continuous operation. ... In a combined cycle power plant, or combined cycle gas turbine (CCGT) plant, a gas turbine generator generates electricity and the waste heat from the gas turbine is used to make steam to generate additional electricity via a steam turbine, this last step enhances the efficiency of electricity generation. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ...

OTEC uses the temperature difference of ocean water on the surface and ocean water from the depths, a small difference of perhaps 25 degrees Celsius, and so the efficiency must be low. The combined cycle gas turbines use natural-gas fired burners to heat air to near 1530 degrees Celsius, a difference of a large 1500 degrees Celsius, and so the efficiency can be large when the steam-cooling cycle is added in. ^[2]

Everyday examples

Examples of everyday heat engines include: the steam engine, the diesel engine, and the gasoline (petrol) engine in an automobile. A common toy that is also a heat engine is a drinking bird. All of these familiar heat engines are powered by the expansion of heated gases. The general surroundings are the heat sink, providing relatively cool gases which, when heated, expand rapidly to drive the mechanical motion of the engine. // The term steam engine may also refer to an entire railroad steam locomotive. ... This article does not cite any references or sources. ... 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. ... “Car” and “Cars” redirect here. ... Drawing of two Drinking Birds. ...

Examples of heat engines

It is important to note that although some cycles have a typical combustion location (internal external), they often can be implemented as the other combustion cycle. For example, John Ericsson developed an external heated engine running on a cycle very much like the earlier Diesel cycle. In addition, the externally heated engines can often be implemented in open or closed cycles. John Ericsson (1803-1889) This article is about John Ericsson, the Swedish and American inventor. ... The Diesel cycle is the combustion process of a type of reciprocating internal combustion engine, in which the fuel is ignited by the heat generated in first compressing air in the combustion chamber, into which is then injected the fuel, as opposed to it being ignited by a spark plug...

What this boils down to is there are thermodynamic cycles and a large number of ways of implementing them with mechanical devices called engines.

Phase change cycles

In these cycles and engines, the working fluids are gases and liquids. The engine converts the working fluid from a gas to a liquid.

• Rankine cycle (classical steam engine)
• Regenerative cycle (steam engine more efficient than Rankine cycle)
• Vapor to liquid cycle (Drinking bird)
• Liquid to solid cycle (Frost heaving — water changing from ice to liquid and back again can lift rock up to 60 m.)
• Solid to gas cycle (Dry ice cannon — Dry ice sublimes to gas.)

The Rankine cycle is a thermodynamic cycle. ... // The term steam engine may also refer to an entire railroad steam locomotive. ... // The term steam engine may also refer to an entire railroad steam locomotive. ... The Rankine cycle is a thermodynamic cycle. ... Drawing of two Drinking Birds. ... Frost heaving (or frost heave) occurs when soil expands upward or outward and contracts due to freezing and thawing. ... Please wikify (format) this article or section as suggested in the Guide to layout and the Manual of Style. ...

Gas only cycles

In these cycles and engines the working fluid are always like gas:

• Carnot cycle (Carnot heat engine)
• Ericsson Cycle (Caloric Ship John Ericsson)
• Stirling cycle (Stirling engine, thermoacoustic devices)
• Internal combustion engine (ICE):
  • Otto cycle (eg. Gasoline/Petrol engine, high-speed diesel engine)
  • Diesel cycle (eg. low-speed diesel engine)
  • Atkinson Cycle (Atkinson Engine)
  • Brayton cycle or Joule cycle originally Ericsson Cycle (gas turbine)
  • Lenoir cycle (e.g., pulse jet engine)
  • Miller cycle

The Carnot cycle is a particular thermodynamic cycle, modeled on the Carnot heat engine, studied by Nicolas Léonard Sadi Carnot in the 1820s and expanded upon by Benoit Paul Émile Clapeyron in the 1830s and 40s. ... A Carnot heat engine is a hypothetical engine that operates on the reversible Carnot cycle. ... This article or section seems not to be written in the formal tone expected of an encyclopedia entry. ... The Stirling engine is a type of hot air engine, invented in 1816 by the Rev. ... Cut away diagram of a Rhombic Drive Beta Stirling Engine Design Pink - Hot cylinder wall, Dark grey - Cold cylinder wall (with coolant inlet and outlet pipes in Yellow), Dark Green - Thermal insulation separating the two cylinder ends, Light Green - Displacer piston, Dark Blue - Power piston, Light Blue - Flywheels, Not Shown... Sonic or thermoacoustic refrigeration is a technology that uses high-amplitude sound waves in a pressurised gas to pump heat from one place to another. ... 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. ... The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today ( cars and trucks, generators, etc). ... Gasoline (or petrol) engine is a type of internal combustion engine which is often used for automobiles, aircraft, small mobile vehicles such as lawnmowers or motorcycles, and outboard motors for boats. ... This article does not cite any references or sources. ... The Diesel cycle is the combustion process of a type of reciprocating internal combustion engine, in which the fuel is ignited by the heat generated in first compressing air in the combustion chamber, into which is then injected the fuel, as opposed to it being ignited by a spark plug... This article does not cite any references or sources. ... The Atkinson cycle engine is a type of Internal combustion engine invented by James Atkinson in 1882. ... The Brayton cycle is a constant-pressure cycle named after George Brayton (1830–1892), the American engineer who developed it. ... The Brayton cycle is a power cycle generally associated with the gas turbine. ... This article or section seems not to be written in the formal tone expected of an encyclopedia entry. ... This machine has a single-stage centrifugal compressor and turbine, a recuperator, and foil bearings. ... The Lenoir cycle is an idealised thermodynamic cycle for the pulse jet engine. ... It has been suggested that this article or section be merged with valveless pulse jet. ... kill them In engineering, the Miller cycle is a combustion process used in a type of four-stroke internal combustion engine. ...

Liquid only cycles

In these cycles and engines the working fluid are always like liquid:

• Stirling Cycle (Malone engine)

The Stirling engine is a type of hot air engine, invented in 1816 by the Rev. ...

Electron cycles

• Thermoelectric (Peltier-Seebeck effect)
• Thermionic emission
• Thermotunnel cooling

The Peltier-Seebeck effect, or thermoelectric effect, is the direct conversion of heat differentials to electric voltage and vice versa. ... Closeup of the filament on a low pressure mercury gas discharge lamp showing white thermionic emission mix coating on the central portion of the coil. ... Thermotunnel cooling is similar to thermionic emission cooling in that fast moving electrons carry heat across a gap but cannot return due to a voltage difference. ...

Magnetic cycles

• Thermo-magnetic motor (Tesla)

Cycles used for refrigeration

A refrigerator is a heat pump: a heat engine in reverse. Work is used to create a heat differential. Many cycles can run in reverse to move heat from the cold side to the hot side, making the cold side cooler and the hot side hotter. Internal combustion engine versions of these cycles are, by their nature, not reversible. “Freezer” redirects here. ... A diagram of a simple heat pumps vapor-compression refrigeration cycle: 1) condenser, 2) expansion valve, 3) evaporator, 4) compressor. ...

• Vapor-compression refrigeration
• Stirling cryocooler
• Gas-absorption refrigerator
• Air cycle machine
• Vuilleumier refrigeration

Vapor-compression refrigeration[1][2] is one of the many refrigeration methods available for use. ... Cut away diagram of a Rhombic Drive Beta Stirling Engine Design Pink - Hot cylinder wall, Dark grey - Cold cylinder wall (with coolant inlet and outlet pipes in Yellow), Dark Green - Thermal insulation separating the two cylinder ends, Light Green - Displacer piston, Dark Blue - Power piston, Light Blue - Flywheels, Not Shown... The absorption refrigerator is a refrigerator that utilizes a heat source to provide the energy needed to drive the cooling system rather than being dependent on electricity to run a compressor. ... An Air Cycle Machine (ACM) is the refrigeration unit of the environmental control system used in pressurized turbine-powered aircraft. ...

Efficiency

The efficiency of a heat engine relates how much useful power is output for a given amount of heat energy input.

From the laws of thermodynamics: Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dunamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ...

where

dW = − PdV is the work extracted from the engine. (It is negative since work is done by the engine.)

dQ_h = T_hdS_h is the heat energy taken from the high temperature system. (It is negative since heat is extracted from the source, hence ( − dQ_h) is positive.)

dQ_c = T_cdS_c is the heat energy delivered to the cold temperature system. (It is positive since heat is added to the sink.)

In other words, a heat engine absorbs heat energy from the high temperature heat source, converting part of it to useful work and delivering the rest to the cold temperature heat sink.

In general, the efficiency of a given heat transfer process (whether it be a refrigerator, a heat pump or an engine) is defined informally by the ratio of "what you get" to "what you put in."

In the case of an engine, one desires to extract work and puts in a heat transfer.

The theoretical maximum efficiency of any heat engine depends only on the temperatures it operates between. This efficiency is usually derived using an ideal imaginary heat engine such as the Carnot heat engine, although other engines using different cycles can also attain maximum efficiency. Mathematically, this is due to the fact that in reversible processes, the change in entropy of the cold reservoir is the negative of that of the hot reservoir (i.e., dS_c = − dS_h), keeping the overall change of entropy zero. Thus: A Carnot heat engine is a hypothetical engine that operates on the reversible Carnot cycle. ... A reversible process (or reversible cycle if the process is cyclic) , in thermodynamics, is a process that can be reversed by means of infinitesimal changes in some property of the system (Sears and Salinger, 1986). ... Ice melting - classic example of entropy increasing[1] described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of the body of ice. ...

where T_h is the absolute temperature of the hot source and T_c that of the cold sink, usually measured in kelvin. Note that dS_c is positive while dS_h is negative; in any reversible work-extracting process, entropy is overall not increased, but rather is moved from a hot (high-entropy) system to a cold (low-entropy one), decreasing the entropy of the heat source and increasing that of the heat sink. Absolute zero is the lowest temperature that can be obtained in any macroscopic system. ... The kelvin (symbol: K) is a unit increment of temperature and is one of the seven SI base units. ...

The reasoning behind this being the maximal efficiency goes as follows. It is first assumed that if a more efficient heat engine than a Carnot engine is possible, then it could be driven in reverse as a heat pump. Mathematical analysis can be used to show that this assumed combination would result in a net decrease in entropy. Since, by the second law of thermodynamics, this is forbidden, the Carnot efficiency is a theoretical upper bound on the efficiency of any process. Ice melting - classic example of entropy increasing[1] described in 1862 by Rudolf Clausius as an increase in the disgregation of the molecules of the body of ice. ... The second law of thermodynamics is an expression of the universal law of increasing entropy. ...

Empirically, no engine has ever been shown to run at a greater efficiency than a Carnot cycle heat engine.

Figure 2: Carnot cycle efficiency

Figure 3: Carnot cycle efficiency

Here are two plots, Figure 2 and Figure 3, for the Carnot cycle efficiency. One plot indicates how the cycle efficiency changes with an increase in the heat addition temperature for a constant compressor inlet temperature, while the other indicates how the cycle efficiency changes with an increase in the heat rejection temperature for a constant turbine inlet temperature. Image File history File links GFImg3. ... Image File history File links GFImg3. ... Image File history File links GFImg4. ... Image File history File links GFImg4. ...

Other criteria of heat engine performance

One problem with the ideal Carnot efficiency as a criterion of heat engine performance is the fact that by its nature, any maximally-efficient Carnot cycle must operate at an infinitesimal temperature gradient. This is due to the fact that any transfer of heat between two bodies at differing temperatures is irreversible, and therefore the Carnot efficiency expression only applies in the infinitesimal limit. The major problem with that is that the object of most heat engines is to output some sort of power, and infinitesimal power is usually not what is being sought.

A different measure of heat engine efficiency is given by the endoreversible process, which is identical to the Carnot cycle except in that the two processes of heat transfer are not reversible. As derived in Callen (1985), the efficiency for such a process is given by:

This model does a better job of predicting how well real-world heat engines can do, as can be seen in the following table (Callen):

As shown, the endoreversible efficiency much more closely models the observed data. West Thurrock is a place in the borough of Thurrock in England. ... Mohave Generating Station, a 1,580 MW coal power plant near Laughlin, Nevada A fossil fuel power plant is an energy conversion center that combusts fossil fuels to produce electricity, designed on a large scale for continuous operation. ... Qinshan Phase III Units 1 & 2, located in Zhejiang China: Two CANDU 6 reactors, designed by Atomic Energy of Canada Limited (AECL), owned and operated by the Third Qinshan Nuclear Power Company Limited. ... A nuclear power station. ... Larderello is a geologically active area of southern Tuscany, Italy, which is renowned for its geothermal productivity. ... Krafla Geothermal Station in northeast Iceland Geothermal power is the use of geothermal heat to generate electricity. ...

Heat engine enhancements

Engineers have studied the various heat engine cycles extensively in an effort to improve the amount of usable work they could extract from a given power source. The Carnot Cycle limit cannot be reached with any gas-based cycle, but engineers have worked out at least two ways to possibly go around that limit, and one way to get better efficiency without bending any rules.

1) Increase the temperature difference in the heat engine. The simplest way to do this is to increase the hot side temperature, and is the approach used in modern combined-cycle gas turbines. Unfortunately, NOx production and material limits (melting the turbine blades) place a hard limit to how hot you can make a workable heat engine. Modern gas turbines are about as hot as they can become and still maintain acceptable NOx pollution levels. Another way of increasing efficiency is to lower the output temperature. Once new method of doing so is to use mixed chemical working fluids, and then exploit the changing behavior of the mixtures. One of the most famous is the so-called Kalina Cycle, which uses a 70/30 mix of ammonia and water as its working fluid. This mixture allows the cycle to generate useful power at considerably lower temperatures than most other processes.

2) Exploit the physical properties of the working fluid. The most common such exploit is the use of water above the so-called critical point, or so-called supercritical steam. The behavior of fluids above their critical point changes radically, and with materials such as water and carbon dioxide it is possible to exploit those changes in behavior to extract greater thermodynamic efficiency from the heat engine, even if it is using a fairly conventional Brayton or Rankine cycle. A newer and very promising material for such applications is CO₂. SO₂ and xenon have also been considered for such applications, although SO₂ is a little toxic for most.

3) Exploit the chemical properties of the working fluid. A fairly new and novel exploit is to use exotic working fluids with advantageous chemical properties. One such is nitrogen dioxide (NO₂), a toxic component of smog, which has a natural dimer as di-nitrogen tetraoxide (N₂O₄). At low temperature, the N₂O₄ is compressed and then heated. The increasing temperature causes each N₂O₄ to break apart into two NO₂ molecules. This lowers the molecular weight of the working fluid, which drastically increases the efficiency of the cycle. Once the NO₂ has expanded through the turbine, it is cooled by the heat sink, which causes it to recombine into N₂O₄. This is then fed back to the compressor for another cycle. Such species as aluminum bromide (Al₂Br₆), NOCl, and Ga₂I₆ have all been investigated for such uses. To date, their drawbacks have not warranted their use, despite the efficiency gains that can be realized. ^[3]

Heat engine processes

Each process is one of the following: An external combustion engine (EC engine) is a heat engine where an internal working fluid is heated, often from an external source, through the engine wall or a heat exchanger. ... The Carnot cycle is a particular thermodynamic cycle, modeled on the Carnot heat engine, studied by Nicolas Léonard Sadi Carnot in the 1820s and expanded upon by Benoit Paul Émile Clapeyron in the 1830s and 40s. ... The Stirling engine is a type of hot air engine, invented in 1816 by the Rev. ... This article or section seems not to be written in the formal tone expected of an encyclopedia entry. ... An internal combustion engine is an engine that is powered by the expansion of hot combustion products of fuel directly acting within an engine. ... The four-stroke cycle of an internal combustion engine is the cycle most commonly used for automotive and industrial purposes today ( cars and trucks, generators, etc). ... The Diesel cycle is the combustion process of a type of reciprocating internal combustion engine, in which the fuel is ignited by the heat generated in first compressing air in the combustion chamber, into which is then injected the fuel, as opposed to it being ignited by a spark plug... The Brayton cycle is a constant-pressure cycle named after George Brayton (1830–1892), the American engineer who developed it. ...

• isothermal (at constant temperature, maintained with heat added or removed from a heat source or sink)
• isobaric (at constant pressure)
• isometric/isochoric (at constant volume)
• adiabatic (no heat is added or removed from the system during adiabatic process)

An isothermal process is a thermodynamic process in which the temperature of the system stays constant: ΔT = 0. ... An isobaric process is a thermodynamic process in which the pressure stays constant; . The heat transferred to the system does work but also changes the internal energy of the system: according to the first law of thermodynamics, where W is work done by the system, E is internal energy, and... Isochoric Process in the PV-diagram An isochoric process, also called an isometric process or an isovolumetric process, is a thermodynamic process in which the volume stays constant; . This implies that the process does no pressure-volume work, since such work is defined by , where P is pressure (no minus... In thermodynamics, an adiabatic process or an isocaloric process is a thermodynamic process in which no heat is transferred to or from the working fluid. ...

References

1. ^ en:Ocean_thermal_energy_conversion
2. ^ U.S. Department of Energy • Office of Fossil Energy, National Energy Technology Laborator: Advanced Turbine Systems. Advancing The Gas Turbine Power Industry
3. ^ Nuclear Reactors Concepts and Thermodynamic Cycles

• Kroemer, Herbert; Kittel, Charles (1980). Thermal Physics, 2nd ed., W. H. Freeman Company. ISBN 0-7167-1088-9. 
• Callen, Herbert B. (1985). Thermodynamics and an Introduction to Thermostatistics, 2nd ed., John Wiley & Sons, Inc.. ISBN 0-471-86256-8. 

This article or section does not cite any references or sources. ...

See also

• Reciprocating engine for a general description of the mechanics of piston engines
• Heat pump
• Carnot heat engine
• Timeline of heat engine technology
• Heat engine classifications

A thermodynamic cycle is a series of thermodynamic processes which returns a system to its initial state. ... A thermodynamic cycle is a series of thermodynamic processes which returns a system to its initial state. ... A stroke is a single action of certain engines. ... The Crower six-stroke engine or Crower Cycle is a concept under development by Bruce Crower. ... Today Internal combustion engines in cars, trucks, motorcycles, construction machinery and many others, most commonly use a four-stroke cycle. ... The Scuderi Split Cycle Engine design is a rethink of the conventional four-stroke Otto cycle internal combustion engine conceived by Carmelo J. Scuderi (1925-2002). ... A six stroke engine is an automobile engine in which the piston of the engine move up and down an additional time for each injection of fuel. ... The two-stroke cycle of an internal combustion engine differs from the more common four-stroke cycle by completing the same four processes (intake, compression, power, exhaust) in only two strokes of the piston rather than four. ... A pistonless rotary engine is an internal combustion engine that does not use pistons in the way a reciprocating engine does, but instead uses one or more rotors, sometimes called rotary pistons. ... The Britalus rotary engine was invented in 1982 by Kenneth W. Porter, P.E., M.S.A.E, of King County, Washington. ... A combustion chamber is part of an engine in which fuel is burned. ... Controlled Combustion Engine (CCE) is a type of internal combustion engine designed by Brad Howell-Smith in 1995. ... A Pratt and Whitney turbofan engine for the F-15 Eagle is tested at Robins Air Force Base, Georgia, USA. The tunnel behind the engine muffles noise and allows exhaust to escape. ... An orbital engine is a type of internal combustion engine, featuring rotary rather than reciprocating motion of its internal parts. ... Components of a typical, four stroke cycle, DOHC piston engine. ... The Quasiturbine or Qurbine engine is a proposed pistonless rotary engine using a four-sided rhomboid rotor whose sides are hinged at the vertices. ... A cold (un-ignited) rocket engine test at NASA A rocket engine is a reaction engine that can be used for spacecraft propulsion as well as terrestrial uses, such as missiles. ... This article does not cite any references or sources. ... The Toroidal engine design is a form of internal combustion engine that features pistons that rotate within a toroidal space. ... The trochilic engine is composed of two mirror image gull wing segments intermeshed and rotating about a common central axis. ... The Twingle engine is a small-capacity two-stroke gasoline engine. ... Wankel Engine in Deutsches Museum Munich, Germany The Wankel rotary engine is a type of internal combustion engine, invented by German engineer Felix Wankel, which uses a rotor instead of reciprocating pistons. ... To meet Wikipedias quality standards, this article or section may require cleanup. ... The D Slide Valve was a form of rectilinear slide valve for use in rotative steam engines invented by William Murdoch and patented in 1799. ... Internal combustion engines using either four-stroke or two-stroke cycle with spark ignition and compression ignition, use poppet valves to allow air to flow through the cylinder head cylinder and exhaust gases out. ... Left side of a Ford Cologne V6 engine, clearly showing a (rusty) cast iron exhaust manifold - three exhaust ports into one pipe. ... In automotive engineering, an engine is referred to as multi-valve (or multivalve) when each cylinder has more than two valves. ... Piston valve in a brass instrument A piston valve is a device used to control the motion of a fluid along a tube or pipe by means of the linear motion of a piston within a chamber or cylinder. ... A poppet valve is a valve consisting of a hole, usually round or oval, and a tapered plug, usually a disk shape on the end of a shaft also called a valve stem. ... Figure 1: A de Laval nozzle, showing approximate flow velocity increasing from green to red in the direction of flow The main type of rocket engine nozzles used in modern rocket engines is the de Laval nozzle which is used to expand and accelerate the combustion gases, from burning propellants... piston engine Bristol Perseus The sleeve valve is a type of valve mechanism for piston engines which have traditionally relied on the more common poppet valve. ... For the use of the term in optics, see piston (optics). ... The Bourke engine was designed by Russell Bourke in the late 1930s, who endeavored to improve upon the Otto cycle engine. ... This page is a candidate for speedy deletion, because: not an article, just links to pictures If you disagree with its speedy deletion, please explain why on its talk page or at Wikipedia:Speedy deletions. ... The hydraulic cylinders on this excavator control the machines linkages. ... Fairbanks-Morse opposed piston diesel engines on the submarine USS Pampanito. ... The radial engine is an internal combustion engine configuration in which the cylinders point outward from a central crankshaft like the spokes on a wheel. ... This is a disambiguation page — a navigational aid which lists other pages that might otherwise share the same title. ... A single cylinder engine, colloquially known as a one-lunger, is an engine configuration consisting of just one cylinder. ... The Stelzer engine is a diesel engine design proposed by Frank Stelzer. ... Usually found in 4 and 6 cylinder configurations, the straight engine (often designed as inline engine) is an internal-combustion engine with all cylinders aligned in one row, with no or only minimal offset. ... A sphere rotating around its axis. ... In Euclidean geometry, an arc is a closed segment of a differentiable curve in the two-dimensional plane; for example, a circular arc is a segment of a circle. ... The motion of a non-offset piston connected to a crank through a connecting rod (as would be found in internal combustion engines), can be expressed through several mathematical equations. ... piston (top) and connecting rod from typical automotive engine (scale is in centimetres) Components of a typical, four stroke cycle, DOHC piston engine. ... Crankshaft (red), pistons (gray) in their cylinders (blue), and flywheel (black) Continental engine marine crankshafts, 1942 Components of a typical, four stroke cycle, DOHC piston engine. ... monkey ... The parallel motion was a mechanical linkage invented by James Watt in 1784 for his double-acting steam engine. ... The Peaucellier-Lipkin linkage (or Peaucellier-Lipkin cell), invented in 1864, was the first linkage capable of transforming rotary motion into perfect straight-line motion. ... In a piston engine, a piston rod joins a piston to a connecting rod. ... Cut away diagram of a Rhombic Drive Beta Stirling Engine Design Pink - Hot cylinder wall, Dark grey - Cold cylinder wall (with coolant inlet and outlet pipes in Yellow), Dark Green - Thermal insulation separating the two cylinder ends, Light Green - Displacer piston, Dark Blue - Power piston, Light Blue - Flywheels, Not Shown... The Scotch Yoke is a mechanism for converting the horizontal motion of a slider into rotational motion or vice-versa. ... The swashplate is the device that translates the pilots (or autopilots) commands via the helicopter flight controls into motion of the main rotor blades. ... Almen A-4 barrel engine The swashplate engine is a type of reciprocating engine that replaces the common crankshaft with a circulate plate. ... Watts Linkage The Watts linkage was invented by James Watt (1736--1819) to constrain the movement of a piston in a steam engine to move in a straight line. ... The Toroidal engine design is a form of internal combustion engine that features pistons that rotate within a toroidal space. ... The trochilic engine is composed of two mirror image gull wing segments intermeshed and rotating about a common central axis. ...

External links

• Heat Engine
• Webarchive backup: Refrigeration Cycle Citat: "...The refrigeration cycle is basically the Rankine cycle run in reverse..."
• Red Rock Energy Solar Heliostats: Heat Engine Projects Citat: "...Choosing a Heat Engine..."
• Overview of heat engine types
• The rotary piston array machine
• The gyroscope combustion motor
• The external combustion air engine
• Toy Steam Forum official website