external combustion engine
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An external combustion engine (EC engine) is a reciprocating
heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, entropy, and the physical properties of matter and radiation. The behavior of these qu ...

heat engine
where a
working fluid For fluid power, a working fluid is a gas or liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force ...
, contained internally, is heated by combustion in an external source, through the
engine File:Jet engine.svg, 450px, Jet engine uses heat of combustion to generate a high-velocity exhaust as a form of reaction engine. Mechanical energy to power the aircraft's electrical and hydraulic systems can be taken from the turbine shaft, but th ...

engine
wall or a
heat exchanger A heat exchanger is a system used to transfer heat between two or more fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an applied shear stress, or external force. Fluids are a Phase (ma ...

heat exchanger
. The fluid then, by expanding and acting on the
mechanism Mechanism may refer to: *Mechanism (engineering) In engineering, a mechanism is a Machine, device that transforms input forces and movement into a desired set of output forces and movement. Mechanisms generally consist of moving components which m ...
of the engine, produces motion and usable
work Work may refer to: * Work (human activity), intentional activity people perform to support themselves, others, or the community ** Manual labour, physical work done by humans ** House work, housework, or homemaking * Work (physics), the product of ...
.external combustion - Definition from the Merriam-Webster Online Dictionary
/ref> 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

"
Combustion Combustion, or burning, is a high-temperature exothermic In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, radiation, and physical pro ...
" refers to
burning Combustion, or burning, is a high-temperature exothermic In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energy, radiation, and physical pro ...

burning
fuel A fuel is any material that can be made to react with other substances so that it releases energy as thermal energy Thermal radiation in visible light can be seen on this hot metalwork. Thermal energy refers to several distinct physical conc ...

fuel
with an
oxidizer Image:DOT hazmat class 5.1.svg, 125px, Dangerous goods label for oxidizing agents In chemistry, an oxidizing agent (oxidant, oxidizer), or oxidising agent (oxidiser) is a substance that has the ability to oxidize other substances — in other ...
, 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

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

Gas Gas is one of the four fundamental states of matter (the others being solid, liquid A liquid is a nearly incompressible fluid In physics, a fluid is a substance that continually Deformation (mechanics), deforms (flows) under an appl ...
is used in a
Stirling engine File:Stirling Animation.gif, 136px, upBeta-type Stirling engine, with only one cylinder, hot at one end and cold at the other. A loose-fitting displacer shunts the air between the hot and cold ends of the cylinder. A power piston at the open end ...

Stirling engine
. Single-phase
liquid A liquid is a nearly incompressible In fluid mechanics or more generally continuum mechanics, incompressible flow (isochoric process, isochoric flow) refers to a fluid flow, flow in which the material density is constant within a fluid parc ...

liquid
may sometimes be used.


Dual phase

Dual-phase external combustion engines use a
phase Phase or phases may refer to: Science * State of matter, or phase, one of the distinct forms in which matter can exist *Phase (matter) In the physical sciences, a phase is a region of space (a thermodynamic system A thermodynamic system is a ...
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 The Rankine cycle is an idealized thermodynamic cycle A thermodynamic cycle consists of a linked sequence of thermodynamic processes that involve transfer of heat and work into and out of the system, while varying pressure, temperature, and othe ...
.
Steam engine from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energ ...

Steam engine
s are a common example of dual-phase engines. Another example is engines that use the
Organic Rankine cycle The Organic Rankine Cycle (ORC) is named for its use of an Solvent, organic, high molecular mass fluid with a liquid-vapor phase change, or boiling point The boiling point of a substance is the temperature at which the vapor pressure of a li ...
.


See also

*
Organic Rankine cycle The Organic Rankine Cycle (ORC) is named for its use of an Solvent, organic, high molecular mass fluid with a liquid-vapor phase change, or boiling point The boiling point of a substance is the temperature at which the vapor pressure of a li ...
*
Steam engine from Stott Park Bobbin Mill, Cumbria, England A steam engine is a heat engine In thermodynamics Thermodynamics is a branch of physics that deals with heat, Work (thermodynamics), work, and temperature, and their relation to energ ...

Steam engine
s *
Stirling engine File:Stirling Animation.gif, 136px, upBeta-type Stirling engine, with only one cylinder, hot at one end and cold at the other. A loose-fitting displacer shunts the air between the hot and cold ends of the cylinder. A power piston at the open end ...

Stirling engine
s *
Trochilic engine A swing-piston engine is a type of internal combustion engine An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the w ...
*
Internal combustion engine An internal combustion engine (ICE) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal combustion engine, t ...

Internal combustion engine
(ICE) *
Nuclear power Nuclear power is the use of nuclear reactions to produce electricity. Nuclear power can be obtained from nuclear fission, nuclear decay and nuclear fusion reactions. Presently, the vast majority of electricity from nuclear power is produced by ...

Nuclear power
*
Solar thermal rocketA solar thermal rocket is a theoretical spacecraft propulsion Spacecraft propulsion is any method used to accelerate spacecraft and artificial satellite In the context of spaceflight, a satellite is an object that has been intentionally pl ...
(an externally heated rocket) *
Naptha engine A naphtha launch, sometimes called a "vapor launch", was a small motor launch, powered by a naphtha engine. They were a particularly American design, brought into being by a local law that made it impractical to use a steam launch for private use ...
, a variant of the steam engine, using a petroleum liquid as both fuel and working fluid.


References

{{Machines Engines