Daniel Barcus discusses different types of engines in the document, including Stirling engines, diesel engines, and gasoline engines. Stirling engines run at a constant speed and were used until 1915 but are not commonly used today. Diesel engines compress air more than gasoline engines, resulting in very hot combustion that powers the piston. Gasoline engines are the most commonly used today and involve four strokes - intake, compression, combustion, and exhaust - to power the crankshaft through ignition of the fuel. The document provides an overview of the basic workings of different engine types.

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Daniel Barcus
Ms. Bennett
British Literature
3 October 2011
The History and Explanation of Engines
How much does a person really know about engines and how vehicles function?For many
years engines have been used to propel many types of vehicles. There are several types of
engines, and those engine types have several sects. The engines summarized in this paper are
gasoline, diesel, and Stirling engines. Gasoline engines will be focused on the most, though,
because gasoline engines are used in most automobiles today. Each engine serves a purpose
whether it is for fuel efficiency, safety, or cost.
Stirling engines are basic engines. They are sometimes called “external combustion
engines.” When the Industrial Revolution came around, there was a large problem with steam
engines. Steam engines would explode, because during the Industrial Revolution people did not
understand how metal fatigued. Reverend Robert Stirling invented a hot air engine, which is now
called a “Stirling engine.” These engines could not explode, and used much less fuel. The
problem with the Stirling engine is that it would heat up and eventually burn a hole in itself.
Despite this problem, Stirling engines were still used until 1915 (Van Arsdell1091-1093).The
main reason Stirling engines are not used today to power vehicles is because Stirling engines run
at a constant speed and are not easily able to change speeds on the fly like diesel or gasoline
engines (Van Arsdell1093-1094).
Stirling engines are powered by heated air. When the air is heated it expands the piston,
and when the air is cooled it contracts the engine. One side of the engine is kept heated, and the

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other side is kept cool. Because one side has constant heat, and the other is constantly cooled, the
air cycles throughout the engine. Stirling engines are so versatile that they can be heated by the
sun or even by a hot cup of coffee (Van Arsdell1090)!
Diesel engines are used today to power many vehicles. They are used in vehicles such as
pickup trucks, buses, marine crafts, and road-building equipment. The diesel engine is a result of
many years of study on internal combustion engines. Sadi Carnot first started working on this
engine, and it was taken on later by ÉtienneLenori. In 1860,Lenori released the first commercial
internal combustion engine. After a few years, Rudolph Diesel finally perfected the internal
combustion engine and added his own type of fuel (Brady 327). He originally wanted to use coal
dust as fuel, but modern diesel engines use low-cost oil (“Diesel Engine” 646). Diesel engines
are now called the diesel cycle engines. Today the diesel cycle engine is a reliable engine that
serves many purposes(Brady 327).
The diesel engine is a lot stronger than a gasoline engine, mainly because the pistons in
diesel engines compress a lot more than gasoline engines do. An average four-stroke gasoline
engine has thecompression ratio of between 9:1 and 10.5:1, while an average four-stroke direct-
injected diesel engine’s compression ratio is between 15:1 and 17:1. Since the diesel engine
compresses much more than a gasoline engine, the air becomes extremely hot in the diesel
engine and ignites the fuel. Diesel engines inject air into the cylinder, and then the air is
compressed. The air heats up to around 1,200-1,700 degrees Fahrenheit. Fuel is then injected into
the cylinder and ignites, pushing the piston backwards (Brady 327-328).Diesel cycle engines are
more powerful than gasoline engines and use cheaper fuel, but they weigh more, are more costly
to produce, and pollute more.

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Gasoline engines are the most commonly used engines. In 1698, Thomas Savery invented
the “Miner’s Friend” which used steam power to pump water. Thomas Newcomen expanded on
the idea in later years and used a piston inside of the engine which produced constant power. In
1859, Jean-Joseph Etienne Lenoir invented a durable engine that was reliable. Later, in 1862,
Lenoir invented the first automobile. Nikolaus Otto, a grocery salesman, developed the world’s
first four-stroke engine in 1876. Most modern engines are very similar to the Otto engine (Jensen
542-543).
There are many parts to a gasoline engine. First there are the engine bearings. The
bearings hold the crankshaft for the pistons in place. The crankshaft runs through the center of
the engine, holds all of the pistons, and turns when a piston is pushed out or in. The pistons and
piston rings are the heart of the engine. The piston rings keep the pistons air-tight so that when
the fuel is ignited, none of the energy escapes. The pistons take the full force of the ignition,
turning the crankshaft, which in turn turns the timing chains, belts and cam drives. The timing
chains, belts, and cam drives turn the camshafts, and sometimes drive pumps for cooling and oil.
The camshaft has little egg shapes on it which turn and release the lifters, which open and close
the valves in the piston cylinders. There are two valves per cylinder, one for pouring fuel in and
one for letting exhaust out. Finally, there are the spark plugs, which ignite the fuel in the
cylinders(“Replacing Engine Parts”). Gasoline engines consist of many parts, and all of the parts
need to work together flawlessly to get the most out of an engine.
The gasoline engine converts energy into mechanical work. The gasoline engine is called an
internal combustion engine because the energy inside of the engine comes from the combustion
of fuel. The gasoline engine may also be called a spark-ignition engine, because the combustion
in the engine is initiated by a spark from a spark plug. Most legal gasoline engines are four-

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stroke. Four-stroke means that there are four different strokes, or cycles, that the engine goes
through. The first stroke is the intake stroke. The fuel valve opens and fuel pours into the
cylinder. The second stroke is when the fuel valve closes and the piston starts to compress the
fuel. The spark plug ignites the fuel and forces the piston out, which completes the third stroke.
As the piston starts to go back in, the exhaust valve opens and the exhaust is expelled (Amann
557-559). The ignition of the fuel is controlled by an on-board computer, rather than the
mechanical actions of the engine. (Amann 565) Every time the engine completes its four strokes,
the crankshaft turns. Belts are attached to the crankshaft, which turn the camshaft(s). Cam
wheels attached to the camshaft open and close the intake and exhaust valves. There are different
designs for camshafts and valves. For example, sometimes the cam wheels directly push in the
valves, and sometimes cam wheels push an arm which opens and closes the valves. The
crankshaft also may operate the lubrication and cooling systems. Because of the extreme heat
causes by the ignition of the fuel, a lubrication and cooling system are a must; otherwise the
engine could possibly melt. Some engines use water cooling systems, which are mixed with
antifreeze. The water, which gathers heat, is pumped around the engine and is brought to a
radiator. The radiator increases the water’s surface area, and has a fan attached to it which is
turned by the crankshaft. The fan cools the water off quickly in the radiator, so that the water can
cycle through the engine again. The crankcase, which the crankshaft sits in, is filled with oil. A
pump carries the oil to different parts of the engine (Cohen 2167).Much more plays into engines
than just pouring in fuel and turning a key. An engine is its own ecosystem, which has different
parts that work together to help each other.
So far this paper has talked about the single cylinder in an engine. Unfortunately, most
engines have much more than one cylinder. Engines have many different shapes, as well as

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different amounts of cylinders. There are four basic cylinder arrangements: V, inline, horizontal,
and radial. Radial arrangements were used in older aircraft engines, so they are not as common
as the other three. V engines areself-explanatory because they have the shape of a V. Inline
engines, or vertical engines, usually have all of their cylinders facing vertically, or into the air.
Horizontal engines, or flat engines, have two opposite cylinders that are horizontally aligned.
Along with the V, horizontal, and inline cylinder arrangements, engines have different amounts
of cylinders. The arrangement of the cylinders in an engine can be referred to by the initial of the
arrangement and the number of cylinders. For example, a V6 engine would have a V shape and
have six cylinders. An I4 engine would have an inline arrangement and eight cylinders. An H6
engine would have a have a horizontally opposed arrangement, and would have six cylinders.
Finally, an R5 engine would have a radial arrangement and five cylinders. There is really no
limit to how many cylinders one engine can have, but V6, V8, V10, V12, I3, I5, I6, H6, R5, R7,
and R9 are the most common arrangements (Amann 561-562). For vehicles, the arrangement of
the cylinders really matters on what type of vehicle that the engine is put in to. The arrangement
of cylinders does not affect performance by much, though. For example, an H6 engine could put
out almost the same power as a V6 engine. An inline engine is hard to cool, so an inline engine
would be good for a small car, but not a larger vehicle. Inline engines also needs only half as
many camshafts as the other type of engines, so inline engines are slightly lighter and more
reliable. Horizontal engines have low centers of gravity because they are flat and wide. V
engines are more box-shaped, and have some characteristics of horizontal and inline engines.
Some arrangements also might need more metal so they can be mounted correctly. A lot of
factors play into arrangement choice, but when it comes down to performance, all arrangements
perform the same (“Is there a difference between inline and V engine configurations?”).

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There are many types of engines, but the gasoline engine is the most commonly used.
Gasoline engines are used because they are lightweight and very flexible when it comes to
configurations. Stirling engines are very basic engines which use air and heat to create
mechanical energy. Diesel engines are almost a combination of Stirling engines and gasoline
engines because they use heated air to ignite fuel, rather than a spark. Every engine is based
around pistons, which turn a crankshaft that can perform enumerable mechanical tasks. Some
engines sacrifice safety for fuel efficiency, give up fuel efficiency for safety, or change cost for
both.

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Works Cited
Amann, Charles A. “Gasoline Engines.” Macmillan Encyclopedia of Energy.Ed. John
Zumerchik.Vol. 2. New York: Gale, 2001. 556-566. 3 vols. Gale Virtual Reference
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i.do?id=GALE%7CCX3407300128&v=2.1&u=cant48040&it=r&p=GVRL&sw=w>.
Brady, Robert N. “Diesel Cycle Engines.” Macmillan Encyclopedia of Energy.Ed. John
Zumerchik.Vol. 1. New York: Gale, 2001. 326-366. 3 vols. Gale Virtual Reference
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Cohen, M. L. “Internal Combustion Engine.” The Gale Encyclopedia of Science.Ed. K. Lee
Lerner and Brenda Wilmoth Lerner.3rd ed. Vol. 3. Detroit: Gale, 2004. 2164-2167. 6
vols. Gale Virtual Reference Library.Web. 2 Sept. 2011. <http://go.galegroup.com/ps/
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“Diesel Engine.”UXL Encyclopedia of Science.Ed. Rob Nagel.2nd ed. Vol. 4. Detroit: U*X*L,
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“Is there a difference between inline and V engine configurations?” HowStuffWorks.Discovery,
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Jensen, Todd, and P. Andrew Karam.“The Internal Combustion Engine.”Science and Its
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“Replacing Engine Parts.”AA1CAR. N.p., n.d. Web. 7 Sept. 2011. <http://www.aa1car.com/
library/engine2.htm>.
Van Arsdell, Brent H. “Stirling Engines.” Macmillan Encyclopedia of Energy.Ed. John
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