External combustion engine

"External combustion" redirects here. For the album, see External Combustion.

Type of reciprocating heat engine

Model Stirling engine, with external heat from a spirit lamp (bottom right) applied to the outside of the glass displacer cylinder. Newcomen's engine, a precursor of the steam engine, with the boiler heated from beneath Sectioned steam locomotive. Although the fire is within an enclosed firebox, this is still an external combustion engine, as the exhaust gas and the steam working fluid are kept separate. Part of a series on

Aircraft propulsion
Shaft engines:
driving propellers, rotors, ducted fans or propfans

* Internal thermal engines:
* Piston engine
* Diesel engine
* Wankel engine
* Turbines:
* Turboprop
* Turboshaft
* External thermal engines:
* Steam power
* Electric motors:
* Electric aircraft
* Clockwork drives:
* Human-powered

Reaction engines

* Turbines:
* Turbojet
* Turbofan
* Propfan
* Rocket-powered
* Air turborocket
* Air-augmented rocket
* Motorjet
* Pulsejet
* Valveless pulsejet
* Gluhareff Pressure Jet
* Aerospike engine
* Pulse detonation engine
* Rotating detonation engine
* Ramjet
* Scramjet
* Shcramjet

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An external combustion engine (EC engine) is a reciprocating heat engine where a working fluid, contained internally, is heated by combustion in 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.[1] The fluid is then dumped (open cycle), or cooled, compressed and reused (closed cycle). In these types of engines, the combustion is primarily used as a heat source, and the engine can work equally well with other types of heat sources.

## Combustion

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"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; they are not then strictly classed as external combustion engines, but as external thermal engines.

## Working fluid

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The working fluid can be of any composition and the system may be single-phase (liquid only or gas only) or dual-phase (liquid/gas).

### Single phase

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Gas is used in a Stirling engine. Single-phase liquid may sometimes be used.[clarification needed]

### Dual phase

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Dual-phase external combustion engines use a phase transition to convert temperature to usable work, for example from liquid to (generally much larger) gas. This type of engine follows variants of the Rankine cycle. Steam engines are a common example of dual-phase engines. Another example is engines that use the Organic Rankine cycle.

## See also

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* Organic Rankine cycle
* Steam engines
* Stirling engines
* Trochilic engine
* Internal combustion engine (ICE)
* Nuclear power
* Solar thermal rocket (an externally heated rocket)
* Naptha engine, a variant of the steam engine, using a petroleum liquid as both fuel and working fluid.

## References

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1. ^ external combustion - Definition from the Merriam-Webster Online Dictionary

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Thermodynamic cycles

External
combustion / thermal|

Without phase change
(hot air engines)

* Bell Coleman
* Brayton/Joule
* Carnot
* Ericsson
* Stirling
* Stirling (pseudo/adiabatic)
* Stoddard
* Manson

|

With phase change|

* Kalina
* Hygroscopic
* Rankine (Organic Rankine)
* Regenerative

Internal
combustion / thermal|

* Atkinson
* Brayton/Joule
* Diesel
* Expander
* Gas-generator
* Homogeneous charge compression ignition
* Humphrey
* Lenoir
* Miller
* Otto
* Scuderi
* Staged combustion

Mixed|

* Combined
* HEHC
* Mixed/dual

Refrigeration|

* Hampson–Linde
* Kleemenko
* Pulse tube
* Regenerative cooling
* Transcritical
* Vapor absorption
* Vapor-compression
* Siemens
* Vuilleumier
* Ionocaloric

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Machines

Classical simple machines|

* Inclined plane
* Lever
* Pulley
* Screw
* Wedge
* Wheel and axle

Clocks|

* Atomic clock
* Chronometer
* Pendulum clock
* Quartz clock

Compressors and pumps|

* Archimedes' screw
* Eductor-jet pump
* Hydraulic ram
* Pump
* Trompe
* Vacuum pump

External combustion engines|

* Steam engine
* Stirling engine

Internal combustion engines|

* Gas turbine
* Reciprocating engine
* Rotary engine
* Nutating disc engine

Linkages|

* Pantograph
* Peaucellier-Lipkin

Turbine|

* Gas turbine
* Jet engine
* Steam turbine
* Water turbine
* Wind generator
* Windmill

Aerofoil|

* Sail
* Wing
* Rudder
* Flap
* Propeller

Electronics|

* Vacuum tube
* Transistor
* Diode
* Resistor
* Capacitor
* Inductor

Vehicles|

* Automobile

Miscellaneous|

* Mecha
* Robot
* Agricultural
* Seed-counting machine
* Vending machine
* Wind tunnel
* Check weighing machines
* Riveting machines

Springs|

* Spring (device)

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