cONTENTS PAGE
Introduction.................................................................................................................. Page
2
Boyle’s Law................................................................................................................. Page
2
Charles’s Law............................................................................................................. Page
3
Internal Combustion
Engine.................................................................................... Page
5
Conclusion.................................................................................................................. Page
7
Reference.................................................................................................................... Page
9
The following research paper is based on my
understanding of the Boyle and Charles laws. It will identify my understanding
of the laws in my own words, whilst showing how each law relates to the
internal combustion engine.
Boyle’s Law
Boyle’s
law, which is also known as the Boyle-Mariotte law, was first identified in
1662 by Robert Boyle. The Boyle’s law, one of numerous gas laws, is defined as
the ‘inversely bond between the complete pressure and volume of a gas’. In my
understanding this means, that as long as the gas is at a constant temperature,
the volume of the gas will vary inversely
with its pressure. Shown in the graph below:
When the
pressure is low, the volume is at its highest and vice versa, when its pressure
is high, the volume is low, assuming that the temperature of the gas remains
the same throughout. Using
a capped syringe or a closed engine piston as an example, when the volume
changes the amount of space which is required for the molecules to move will
change. For that reason when the space is smaller, it will require more
pressure to be exerted to adapt to the change.
Another example which uses Boyle’s law is
spray cans; the forceful pressure within the can thrusts outward the liquid
that is within the can. The pressure, that is attempting to escape, pushes the fluid
out of the cap when it is opened. Boyle’s law also can be applied to the human
race breathing, balloons and a car engine.
Boyle created a formula which reads as a
mathematical equation:
P represents the pressure, V is the volume
and k stands for the constant pressure and volume in which is used however this
will only work as long as the temperature is kept stable and unchanged.
Diagram above shows how temperature when kept
stable and unchanged at 300ºf, the volume will decrease as pressure builds up.
As this is Boyle’s Law, it will only work because the temperature is constant
to ensure that there is a relationship between pressure and volume.
Charles’s Law
Charles’s law, also known as the law of
volumes, was found by Jacques Charles in 1802. Charles’s law is dealt in a
different situation however is similar to the Boyle’s law which deals with the
same variables. My understanding of this gas law is that it reviews the
temperature and volume that is directly proportionate to each other at a
constant pressure. This means that the volume of an object will increase if the
temperature increases however this is only if the pressure is kept stable and
constant throughout.
According to Benson (2011), an example used
was the car tyres, during the months of summer months the tyres increase whilst
winter months it will decrease in volume. Another example that I believe uses
Charles’s Law is a bottle of fizzy drink. When the fizzy drink is cold, there
is not that much pressure released when the bottle is opened however if it was
warm, there is a build-up of pressure to spurt out of the bottle. Yet if it was
placed into direct sunlight, image the explosion that could be caused.
Equation that was found to be used by
Charles’ to describe their findings is a shown below:
V represents the volume, T is the temperature
and the constant variable used is the pressure.
The diagram above shows that when pressure is kept at
1.50kPa, the volume of a given mass of an ideal gas will either increase or
decrease together. As the temperature increases, the volume increases too and
also the other way, when temperature decreases, volume will do the same. This
can be written as:
Internal Combustion Engine
Both Boyle’s and Charles's laws assume that
one of the variables is controlled. Using Boyle’s law, a car engine works when
there is a sudden increase of pressure from the combustion of the fuel to
ensure it expands in the cylinder and thrusts out into the piston, causing the
crankshaft to work. The following examples used below to demonstrate Boyle’s
and Charles’s Law being used within the internal combustion engine is based on
the assumption that there is a constant variable however in reality there isn’t
really a chance that you will find it suitable as things change.
Boyle’s Law:
Assuming that the combustion chamber is
filled with gas, the piston will be moving in an upwards movement. This causing
the volume of the gas to decrease and increase pressure from the gas. May and
Simpson (2007), states that at the “peak compression, one should expect the air
to be compressed to about 1/8 of its original volume” (p.
135).
The diagram above shows that during the compression
stroke (assuming that temperature is constant), gas particles commence to
decrease if the fuel particle increases. However as shown once the volume of
the fuel decreases, an increase of pressure occurs causing Boyle’s law to take
place.
Charles’s Law:
The
example below uses the absolute pressure of the gases or the amount of gas
found in the internal combustion engine. During the power stroke, the constant variable may
change (Real life applications. n.d.).
Spark ignition:
The gases that are created from the combustion process
are done in very high temperatures. As there is a high exposure to temperature,
the gases result in an increase in volume. The spark plug when sparked will
burn a mixture of heat and other gases. In this process, you will be able to
witness the beauty of Charles’s law as the volume will increase due to the
temperature. In reality you will see this likely when the fuel and air
combustion are exposed to high temperature and expands in volume. This causes
the cylinder wall and piston to be forced outwards and pushes the piston head
downwards. This continues till it is passed to the conrod, crankshaft and
allowing the crankshaft to move in a circular motion.
Compression ignition:
Before entering the power stroke, air is compressed
into small molecules (Clark, 2002). The temperature of the air is increase
during the stroke of power and fuel is injected into the cylinder to cause a
mixture of hot air and fuel particles. As Charles’s law illustrates the
importance of temperature and volume with the constant amount of pressure, the
gases within that is exposed to high temperature will increase in volume to
push the piston downwards to ensure the transfer of movement to the crankshaft to
turn over (May & Simpson, 2011).
Conclusion
Boyle’s Law reviews the volume and pressure and its
relationship with each other whilst Charles’s Law identified the relationship
between the volume and temperature. Two different gases however very similar
ideas of both requiring a constant variable to ensure that their experiment
works. Boyle’s Law requires the stable temperature to ensure it continues to
work whereas Charles’s Law required the pressure to remain constant.
Boyle’s Law has been identified and has been discussed
to be used within an internal combustion engine however theoretical this is not
shown. There is an aim within the strokes of the compression to decrease the
volume and to continue to increase the pressure found in the combustion
chamber. The likelihood of collision to occur between atomized fuel and air
particles are increased as the concentration of air particles increases too.
Charles’s Law reviews the volume and temperature of a
gas that are proportionate to each other. The concept used within this theory can
be found to be used in the spark ignition and compression ignition within the
internal combustion engine. The cylinder walls are likely to enlarge due to the
air fuel gases. The expansion of the cylinder wall ensures the pressure of the
gas to move the piston head therefore allowing movement and force into the
crankshaft.
Reference
Anonymous. (n.d). Gases
- Real Life Applications. (n.d). Retrieved April 05 2012 from
http://www.scienceclarified.com/everyday/Real-Life-Chemistry-Vol-1/Gases-Real-life-applications.html
Anonymous. (n.d). How
Does Boyle's law & Charles's Law Apply To Internal Combustion Engine?.
Retrieved April 13 2012 from http://www.experts123.com/q/how-does-boyles-law-and-charles-law-apply-to-internal-combustion-engine.html
Benson, T. (2011). Boyle's Law.
Retrieved April 12, 2012, from
http://www.grc.nasa.gov/WWW/k-12/airplane/boyle.html
Clark, J. (2002). The Effect Of Pressure
On Reaction Rates. Retrieved April 12 2012 from
http://www.chemguide.co.uk/physical/basicrates/pressure.html
May, E. &
Simpson, L. (2007). Engine Fundamentals. In A. Evans et al., Automotive
Mechanics. 1(8). 133 – 148.
May, E., & Simpson, L. (2011). Automotive Mechanics – Volume 1. (8th
ed.). Australia: McGraw Hill Australia Ltd.
May, E., & Simpson, L. (2011). Automotive Mechanics – Volume 2. (8th
ed.). Australia: McGraw Hill Australia Ltd.
West, J. B. (1999). The original presentation
of Boyle's Law. Journal of applied Physiology, 1(98), 31 – 39.
