Page 20 - Piston Engine-Based Power Plants

CHAPTER 2 2

Fuels and Energy Resources
for Reciprocating Engines

Reciprocating engines are heat engines and they require a source of
heat energy if they are to be able to generate useful work. For an inter-
nal combustion engine this is normally supplied by a liquid or gaseous
fuel that can be ignited in air within the combustion chamber, the cyl-
inder of the engine, increasing the temperature and pressure of the gas
inside the chamber and forcing the piston to move so as to expand the
volume within the cylinder. External combustion engines often use the
same fuels but they can also exploit a variety of other energy sources
including solid fuels and solar radiation.

Many engines use liquid fuels such as gasoline or diesel because these
are easily transportable and have a high energy density. This has made
them attractive as automotive fuels both because a small reservoir of fuel
can be used to carry a vehicle a long way and because the nature of the
fuel makes it easy to distribute through gasoline stations along highways.
In remote regions, such fuels can be supplied in bulk in large drums or
tankers and this made the diesel engine the most important means of gen-
erating electric power for remote communities during the twentieth cen-
tury. Another liquid fuel is liquefied propane gas (LPG). This is used in
vehicles but is less likely to be used in stationary applications. Its advan-
tage is that it produces lower emissions that either diesel or gasoline and
can lead to longer engine life and lower maintenance costs.

The main gaseous fuel used in reciprocating engines is natural gas
although there are other types of gas, in particular biogas, that can be
used to fire them too. Although natural gas can be supplied in lique-
fied form as liquefied natural gas, LNG, it is normally provided via
pipeline. Where a pipeline supply is available, gas engines are in com-
mon use. However there are many regions without any natural gas
infrastructure and such regions cannot exploit these engines. For some
of these, the use of bulk LNG supply is possible but in most cases and
alternative liquid fuel, usually diesel, is preferred.

Piston Engine-Based Power Plants. DOI: https://doi.org/10.1016/B978-0-12-812904-3.00002-1
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