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EXHAUST GAS HEAT RECOVERY POWER
GENERATION SYSTEM
SYNOPSIS
This paper proposes and implements a thermoelectric waste heat energy recovery
system for internal combustion engine automobiles, including gasoline vehicles and
hybrid electric vehicles. The key is to directly convert the heat energy from automotive
waste heat to electrical energy using a thermoelectric generator, which is then regulated
by a DCDC uk converter to charge a battery using maximum power point tracking.
ence, the electrical power stored in the battery can be maximi!ed. "oth analysis and
experimental results demonstrate that the proposed system can work well under different
working conditions, and is promising for automotive industry.
#ig. $. %nergy flow path in internal combustion engine
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6V2P-4VYW63R-2&_user=10&_coverDate=06/30/2009&_alid=990449556&_rdoc=1&_orig=search&_cdi=5708&_sort=r&_docanchor=&view=c&_ct=12641&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&_fmt=full&md5=04c0dbbdec06df1ffb33f0bba6ee0a43#fig28/12/2019 Exhaust Gas Heat Recovery Power Generation
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INTRODUCTION
%ven a highly efficient combustion engine converts only about one&third of
the energy in the fuel into mechanical power serving to actually drive the car. The rest is
lost through heat discharged into the surroundings or, 'uite simply, leaves the vehicle as
(waste heat). Clearly, this offers a great potential for the further reduction of C*+
emissions which the "- roup/s engineers are seeking to use through new concepts
and solutions.
The generation of electric power in the motor vehicle is a process chain sub0ect to
significant losses. 1uite simply because the chemical energy contained in the fuel is first
converted into mechanical energy and then, via an generator, into electric power. 2ow
the "- roup/s engineers are working on a technology able to convert the thermal
energy contained in the exhaust gas gas directly into electric power. This thermoelectric
process of recovering energy and generating power by means of semi&conductor elements
has already been used for decades by 2343, the 54 4pace 3gency, in space probes
flying into outer space.
5ntil 0ust a few years ago, however, such thermoelectric generators 6T%s7 were
unsuitable for use in the automobile due to their low level of efficiency. "ut since
significant progress has been made in materials research in recent times, the performance
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and output of such modules has increased significantly. To generate electric power in the
vehicle a thermoelectric generator is integrated in the exhaust gas manifold.
-hile the electric power such a system is able to generate is still relatively small at
a maximum of +88 -, rapid progress in materials research already makes the ambitious
ob0ective of generating up to $,888 - a realistic and by all means feasible proposition.
This energy regeneration system also offers additional effects, such as providing the
engine or the heating system with extra heat when starting the engine cold. ence, the
thermoelectric generator is an ideal partner for "rake %nergy 9egeneration, one of the
features of "- %fficient Dynamics. #or while "rake %nergy 9egeneration serves to
supply energy in overrun and when applying the brakes, T% offers its benefits when
motoring is really fun, that is when accelerating and en0oying the power of the car. :n
future thermoelectric generators will be able to reduce fuel consumption under realistic,
customer&oriented driving conditions by up to ; per cent.
al power. :n this paper, a background on the basic concepts of thermoelectric power
generation is presented and recent patents of thermoelectric power generation with their
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important and relevant applications to waste&heat energy are reviewed and discussed.
Currently, waste heat powered thermoelectric generators are utili!ed in a number of
useful applications due to their distinct advantages. These applications can be categori!ed
as micro& and macro&scale applications depending on the potential amount of heat waste
energy available for direct conversion into electrical power using thermoelectric
generators. icro&scale applications included those involved in powering electronic
devices, such as microchips. 4ince the scale at which these devices can be fabricated
from thermoelectric materials and applied depends on the scale of the miniature
technology available.
Therefore, it is expected that future developments of these applications tend to
move towards nano technology. The macro&scale waste heat applications included to ; years for an automobile
battery. *f the different types of secondary cells, the lead&acid type has the highest
output voltage, which allows fewer cells for a specified battery voltage.
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CONSTRUCTION:
:nside a lead&acid battery, the positive and negative electrodes consist of a group
of plates welded to a connecting strap. The plates are immersed in the electrolyte,
consisting of B parts of water to > parts of concentrated sulfuric acid. %ach plate is a grid
or framework, made of a lead&antimony alloy. This construction enables the active
material, which is lead oxide, to be pasted into the grid. :n manufacture of the cell, a
forming charge produces the positive and negative electrodes. :n the forming process,
the active material in the positive plate is changed to lead peroxide 6pbo7. The
negative electrode is spongy lead 6pb7.
3utomobile batteries are usually shipped dry from the manufacturer. The
electrolyte is put in at the time of installation, and then the battery is charged to from the
plates. -ith maintenance&free batteries, little or no water need be added in normal
service. 4ome types are sealed, except for a pressure vent, without provision for adding
water.
The construction parts of battery are shown in figure.
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COMBUSTION CHAMBER:
:t is the space exposed in the upper part of the cylinder where the combustion of
fuel takes place.
CONNECTING ROD:
:t inter connects the piston and the crankshaft and transmits the reciprocating
motion of the piston into the rotary motion of crankshaft.
CRACKSHAFT:
:t is a solid shaft from which the power is transmitted to the clutch.
CAM SHAFT:
:t is drive by the crankshaft through timing gears and it is used to control the
opening and closing of two valves.
CAM:
These are made as internal part of the camshaft and are designed in such a way to open
the valves at the current timing.
PISTON RINGS:
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:t provides a tight seal between the piston and cylinder wall and preventing leakage of
combustion gases.
GUDGEON PIN:
:t forms a link between the small end of the connecting rod and the piston.
INLET:
The pipe which connects the intake system to the inlet valve of the engine end throughwhich air or air fuel mixture is drawn in to the cylinder.
EXHAUST GAS MANIFOLD:
The pipe which connects the exhaust gas system to the exhaust gas valve of the engine
through which the product of combustion escape in to the atmosphere.
INLET AND EXHAUST GAS VALVE:
They are provided on either on the cylinder head or on the side of the cylinder and
regulating the charge coming in to the cylinder and for discharging the product of
combustion from the cylinder.
FLYWHEEL:
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:t is a heavy steel wheel attached to the rear end of the crank shaft. :t absorbs energy
when the engine speed is high and gives back when the engine speed is low.
TOP DEAD CENTER:
This refers to the position of the crankshaft when the piston is in its top most
position, i.e., the position closest to the cylinder head.
BOTTOM DEAD CENTER:
This refers to the position of the crankshaft when the piston is in lowest position,
i.e., the position farthest from the cylinder head.
NOMENCLATURE:
BORE:
This is the diameter of the engine cylinder.
STROKE:
Distance traveled by the piston in moving from TDC to the "DC is called stroke.
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ENGINE CAPACITY:
This is a total piston displacement or the swept volume of all the cylinders.
Power:
:t is the work done in a given period of time.
Comre!!"o# r$%"o:
:t is a ratio of volume when the piston is at the bottom dead center to the volume
when the piston is at top dead center.
Compression ratio aximum cylinder volume inimum cylinder volume.
INDICATED POWER:
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The power developed within the engine cylinders is called indicated power. This
is calculated from the area of the engine indicator diagram. :t is usually expressed in
kilowatts 6k-7.
BRAKE POWER:
This is the actual power delivered at the crankshaft. :t is obtained by deducting
various power losses in the engine from the indicated power. :t is measured with a
dynamometer and is expressed in kilowatts 6k-7. :t is always less than the indicated
power, due to frictional and pumping losses in the cylinders and the reciprocating
mechanism.
ENGINE TOR&UE:
:t is the force of rotation acting about the crankshaft axis at any given instant of
time.
FUNCTION:
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The spark ignition engine uses a highly volatile fuel, which easily vapori!es. The
fuel is mixed with air before it enters the engine cylinders in the carburetor. This mixture
then enters the cylinders and is compressed. 2ext an electric spark is produced by
ignition system ignites the compressed air fuel mixture.
TE-GENERATOR:
Thermoelectric modules have several ma0or advantages over other means of
generation. Thermoelectric generators help tap an unclaimed resource now considered
waste. eat energy is available in many different places where other sources may not be
available. The modules are solid state and very robust, making them ideal for tasks in
harsh environments such as automobiles, incinerators, and spacecraft. This system is eco&
friendly since it does not harm the environment by causing pollution.
DISADVANTAGES:
TE- GENERATORS:
The modules are expensive about E$88 per $?- module.
They are only ?F efficient.
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GENERATOR
THERMOELECTRIC POWER
%lectricity is no longer a luxuryG it has become a necessity in our everyday lives. ave you ever
had to live without electricity for an extended period of timeH :f so then we know what it is like
to lose all the food in your refrigerator andor chest free!er and shivering in the cold because we
have no heat. %very year thousands, even millions have been in this position when a winter storm
knocked out power over large areas. 2ot to mention rapidly rising energy costs and an uncertain
economic future. 4till many people have become complacent about their electrical energy needs.
4olar panels are a great alternative energy source, but they only produce electricity during
daylight hours. :n addition their daily output is significantly reduced during winter months and
cloudy days. 2ow, using a T% in con0unction with solar and wind, their combined output can
provide all off your home/s energy needs and depending on what state you live in, you will be
getting a check from the electric company instead off a billI
The advantages of using thermoelectric devices88K. 3lthough the above mentioned materials still remain
the cornerstone for commercial and practical applications in thermoelectric power generation,
significant advances have been made in synthesi!ing new materials and fabricating materialstructures with improved thermoelectric performance. %fforts have focused primarily on
improving the material/s figure&of&merit, and hence the conversion efficiency, by reducing the
lattice thermal conductivity.
:n all of the above mentioned T% materials, performance of the "ismuth&Telluride peaks
within a temperature range that is best suited for most cooling and heating applications.
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Figure 4: Performance of Thermoelectric Materials at Various Temperatures
TE-GENERATOR:
"ased on this 4eebeck effect, thermoelectric devices can act as electrical power
generators. 3 schematic diagram of a simple thermoelectric power generator operating based on
4eebeck effect.
Figure 8: Working of thermoelectric generator
3s shown in figure, heat is transferred at a rate of Qhfrom a high&temperature heat source
maintained at Th to the hot 0unction, and it is re0ected at a rate of Qlto a low&temperature sink
maintained at Tl from the cold 0unction. "ased on 4eebeck effect, the heat supplied at the hot
0unction causes an electric current to flow in the circuit and electrical power is produced.
5sing the first&law of thermodynamics 6energy conservation principle7 the difference
between Qh and Ql is the electrical power output we. :t should be noted that this power cycle
intimately resembles the power cycle of a heat engine 6Carnot engine7, thus in this respect a
thermoelectric power generator can be considered as a uni'ue heat engine.
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CHARGE CARRIER DIFFUSION:
Charge carriers in the materials 6electrons in metals, electrons and holes in
semiconductors, ions in ionic conductors7 will diffuse when one end of a conductor is at a
different temperature than the other. ot carriers diffuse from the hot end to the cold end,
since there is a lower density of hot carriers at the cold end of the conductor. Cold
carriers diffuse from the cold end to the hot end for the same reason.
:f the conductor were left to reach e'uilibrium,this process would result in heat
being distributed evenly throughout the conductor 6see heat transfer7. The movement of
heat 6in the form of hot charge carriers7 from one end to the other is called a heat current.
3s charge carriers are moving, it is also an electrical current.
:n a system where both ends are kept at a constant temperature relative to each
other 6a constant heat current flows from one end to the other7, there is a constantdiffusion of carriers. :f the rate of diffusion of hot and cold carriers were e'ual, there
would be no net change in charge. owever, the diffusing charges are scattered by
impurities, imperfections, and lattice vibrations 6phonons7. :f the scattering is energy
dependent, the hot and cold carriers will diffuse at different rates. This will create a
higher density of carriers at one end of the material, and the distance between the positive
and negative charges produces a potential differenceG an electrostatic voltage.
http://www.wordiq.com/definition/Equilibriumhttp://www.wordiq.com/definition/Heat_transferhttp://www.wordiq.com/definition/Heat_currenthttp://www.wordiq.com/definition/Electrical_currenthttp://www.wordiq.com/definition/Scatteringhttp://www.wordiq.com/definition/Phononhttp://www.wordiq.com/definition/Equilibriumhttp://www.wordiq.com/definition/Heat_transferhttp://www.wordiq.com/definition/Heat_currenthttp://www.wordiq.com/definition/Electrical_currenthttp://www.wordiq.com/definition/Scatteringhttp://www.wordiq.com/definition/Phonon8/12/2019 Exhaust Gas Heat Recovery Power Generation
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This electric field, however, will oppose the uneven scattering of carriers, and
e'uilibrium will be reached where the net number of carriers diffusing in one direction is
cancelled by the net number of carriers moving in the opposite direction from the
electrostatic field. This means the thermo power of a material depends greatly on
impurities, imperfections, and structural changes 6which often vary themselves with
temperature and electric field7, and the thermo power of a material is a collection of many
different effects.
PERFROMANCE OF THERMOELECTRICPOWER GENERATORS:
The performance of thermoelectric materials can be expressed as
-here L is the thermoelectric material figure&of&merit, M is the 4eebeck coefficient given
by
-here,
R is the electric resistivity 6inverse of electric conductivity7 and k is the total thermal
conductivity. This figure&of&merit may be made dimensionless by multiplying by
6average absolute temperature of hot and cold plates of the thermoelectric module,7,
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The maximum conversion efficiency of an irreversible thermoelectric power generator
can be estimated using,
The value of the figure&of&merit is usually proportional to the conversion efficiency. The
dimensionless term is therefore a very convenient figure for comparing the
potential conversion efficiency of modules using different thermoelectric materials. :t is
evident that an increase in!T provides a corresponding increase in available heat for
conversion as dictated by the Carnot efficiency, so large NT"s are advantageous. #or
example, a thermoelectric material with an average figure&of&merit of >O$8 &>K&$ would
have a conversion efficiency of approximately +>F when operated over a temperature
difference of @88K.
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ENERGY RECOVERY
:n the effort to save energy by using a thermoelectric module, it is important that
the amount of energy produced by the thermoelectric module during its life time should
be larger than the amount of energy re'uired fabricating it.
The energy recovery years are 8.$ year or less for thermal and nuclear power
generation currently in use,+ years or less for wind power generation which is spotlighted
in recent years, and $8 years for fuel cell power generation. :n the case of thermoelectric
power generation by a "i&Te&based module of +88PC class, the energy recovery years are
8.B; year. Thus, thermoelectric power generation is considered to have sufficient
competitiveness.
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ENGINE
CONSTRUCTION:
:n this pro0ect we use 4J39K :2:T:*2 engine of the type two stroke single
cylinder of Cubic capacity Q; cc. %ngine has a piston that moves up and down in
cylinder. 3 cylinder is a long round air pocket some what like a tin can with a bottom cut
out. Cylinder has a piston which is slightly smaller in si!e than the cylinder the piston is
a metal plug that slides up and down in the cylinder "ore diameter and stroke length of
the engine are ;8mm and ?Rmm respectively.
I+C ENGINE
:nternal combustion engines are those heat engines that burn their fuel inside the
engine cylinder. :n internal combustion engine the chemical energy stored in their
operation.
The heat energy is converted in to mechanical energy by the expansion of gases
against the piston attached to the crankshaft that can rotate.
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PETROL ENGINE:
The engine which gives power to propel the automobile vehicle is a petrol burning
internal combustion engine. Jetrol is a li'uid fuel and is called by the name gasoline
in 3merica. The ability of petrol to furnish power rests on the two basic principlesG
"urning or combustions always accomplished by the production of heat.
-hen a gas is heated, it expands. :f the volume remains constant, the pressure
rises according to Charlie/s law.
WORKING:
There are only two strokes involved namely the compression stroke and the power
strokeG they are usually called as upward stroke and downward stroke respectively.
UPWARD STROKE
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During this stroke, the piston moves from bottom dead center to top dead center,
compressing the charge&air petrol mixture in combustion chamber of the cylinder.
3t the time the inlet port is uncovered and the exhaust gas, transfer ports are
covered. The compressed charge is ignited in the combustion chamber by a spark
given by spark plug.
DOWNWARD STROKE
The charge is ignited the hot gases compress the piston moves downwards, during
this stroke the inlet port is covered by the piston and the new charge is compressed in the
crankcase, further downward movement of the piston uncovers first exhaust gas port and
then transfer port and hence the exhaust gas starts through the exhaust gas port. 3s soon
as the transfer port open the charge through it is forced in to the cylinder, the cycle is then
repeated.
ENGINE TERMINOLOGY:
The engine terminologies are detailed below,
CYLINDER:
:t is a cylindrical vessel or space in which the piston makes a reciprocating
motion.
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PISTON:
:t is a cylindrical component fitted to the cylinder which transmits the bore of
explosion to the crankshaft.
COMBUSTION CHAMBER:
:t is the space exposed in the upper part of the cylinder where the
combustion of fuel takes place.
CONNECTING ROD:
:t inter connects the piston and the crankshaft and transmits the
reciprocating motion of the piston into the rotary motion of crankshaft.
CRACKSHAFT:
:t is a solid shaft from which the power is transmitted to the clutch.
CAM SHAFT:
:t is drive by the crankshaft through timing gears and it is used to control
the opening and closing of two valves.
CAM:
These are made as internal part of the camshaft and are designed in such a way to
open the valves at the current timing.
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FLYWHEEL:
:t is a heavy steel wheel attached to the rear end of the crank shaft. :t absorbs
energy when the engine speed is high and gives back when the engine speed is low.
To ,e$, )e#%er:
This refers to the position of the crankshaft when the piston is in its top mostposition, i.e., the position closest to the cylinder head.
Bo%%om ,e$, )e#%er:
This refers to the position of the crankshaft when the piston is in lowest position,
i.e., the position farthest from the cylinder head.
NOMENCLATURE:
Bore:
This is the diameter of the engine cylinder.
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S%roe:
Distance traveled by the piston in moving from TDC to the "DC is called stroke.
E#."#e )$$)"%/:
This is a total piston displacement or the swept volume of all the cylinders.
Power:
:t is the work done in a given period of time.
Comre!!"o# r$%"o:
:t is a ratio of volume when the piston is at the bottom dead center to the volume
when the piston is at top dead center.
Compression ratio aximum cylinder volume inimum cylinder volume.
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INDICATED POWER:
The power developed within the engine cylinders is called indicated power. This
is calculated from the area of the engine indicator diagram. :t is usually expressed in
kilowatts 6k-7.
BRAKE POWER:
This is the actual power delivered at the crankshaft. :t is obtained by deducting
various power losses in the engine from the indicated power. :t is measured with a
dynamometer and is expressed in kilowatts 6k-7. :t is always less than the indicated
power, due to frictional and pumping losses in the cylinders and the reciprocating
mechanism.
ENGINE TOR&UE:
:t is the force of rotation acting about the crankshaft axis at any given instant of
time.
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FUNCTION:
The spark ignition engine uses a highly volatile fuel, which easily vapori!es. The
fuel is mixed with air before it enters the engine cylinders in the carburetor. This mixture
then enters the cylinders and is compressed. 2ext an electric spark is produced by
ignition system ignites the compressed air fuel mixture.
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EXHAUST GAS HEAT RECOVERY
INTRODUCTION
-aste heat is heat, which is generated in a process by way of fuel combustion orchemical reaction, and then (dumped) into the environment even though it could still be
reused for some useful and economic purpose. The essential 'uality of heat is not the
amount but rather its (value). The strategy of how to recover this heat depends in part on
the temperature of the waste heat gases and the economics involved.
=arge 'uantity of hot flue gases is generated from "oilers, Kilns, *vens and #urnaces. :f
some of this waste heat could be recovered, a considerable amount of primary fuel could
be saved. The energy lost in waste gases cannot be fully recovered. owever, much ofthe heat could be recovered and loss minimi!ed by adopting following measures as
outlined in this chapter.
eat =osses 1uality
Depending upon the type of process, waste heat can be re0ected at virtually any
temperature from that of chilled cooling water to high temperature waste gases from an
industrial furnace or kiln. 5sually higher the temperature, higher the 'uality and more
cost effective is the heat recovery. :n any study of waste heat recovery, it is absolutelynecessary that there should be some use for the recovered heat. Typical examples of use
would be preheating of combustion air, space heating, or pre&heating boiler feed water or
process water. -ith high temperature heat recovery, a cascade system of waste heat
recovery may be practiced to ensure that the maximum amount of heat is recovered at
the highest potential. 3n example of this techni'ue of waste heat recovery would be
where the high temperature stage was used for air pre&heating and the low temperature
stage used for process feed water heating or steam raising.
eat =osses 1uantity
:n any heat recovery situation it is essential to know the amount of heat recoverable and
also how it can be used. 3n example of the availability of waste heat is given belowF 6U $F fuel reduction for every ++oC reduction in
temperature of flue gas.
B.+ Classification and 3pplication
:n considering the potential for heat recovery, it is useful to note all the possibilities, andgrade the waste heat in terms of potential value as shown in the following Table B.$
TABLE 8.1 WASTE SOURCE AND QUALITY
S+No+ So2r)e &2$("%/
$. eat in flue gases. The higher the temperature, the greater
the potential value for heat recovery+. eat in vapour streams. 3s above but when condensed, latent
heat also recoverable.> Convective and radiant heat lost from
exterior of e'uipment
=ow grade if collected may be used for
space heating or air preheats.
?. eat losses in cooling water. =ow grade useful gains if heat is
exchanged with incoming fresh water.
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;. eat losses in providing chilled water
or in the disposal of chilled water. $ a7 igh grade if it can be utili!ed to
reduce demand for refrigeration.
+ b7 =ow grade if refrigeration unitused as a form of heat pump.
@. eat stored in products leaving the
process
1uality depends upon temperature.
Q. eat in gaseous and li'uid effluents
leaving process.
Joor if heavily contaminated and thus
re'uiring alloy heat exchanger.
H".' Temer$%2re He$% Re)o5er/
The following Table B.+ gives temperatures of waste gases from industrial process
e'uipment in the high temperature range. 3ll of these results from direct fuel fired
processes.
Me,"2m Temer$%2re He$% Re)o5er/
The following Table B.> gives the temperatures of waste gases from process e'uipment
in the medium temperature range. ost of the waste heat in this temperature range
comes from the exhaust gas of directly fired process units.
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DESIGN AND CALCULATION
SPECIFICATION OF TWO STROKE PETROL ENGINE:
Type < two strokes
Cooling 4ystem < 3ir Cooled
"ore4troke < ;8 x ;8 mm
Jiston Displacement < RB.+ cc
Compression 9atio < @.@< $
aximum Tor'ue < 8.RB kg&m at ;,;889J
CALCULATION:
Compression ratio 64wept Aolume V Clearance Aolume7 Clearance Aolume
ere,
Compression ratio @.@
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3ssumption$? KWKg mole K.
T >8> K
A A +;>.+B x $8m
olecular weight of air Density of air x A mole
ere,
Density of air at >8>K $.$@; kgm
A mole ++.? mKg&mole for all gases.
olecular weight of air $.$@; x ++.?
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J XY6m6$.$@; x ++.?7Z x B.>$? x >8>[+;>.+B x $8
J >B$$>?.$ m
=et Jressure exerted by the fuel is J
J 629 T7A
Density of petrol B88 Kgm
J XY676B88 x ++.?7Z x B.>$? x >8>[6+;>.+B x $8
J =>+?.8+ m
Therefore Total pressure inside the cylinder
JT JV J
$.8$>+; x $88 K2m
>B$$>?.$ mV =>+?.8+ m $.8$>+; x $88 &&&&&&&&&&&&&&&&&&&&&&&&& 6$7
C$()2($%"o# o* $"r *2e( r$%"o:
Carbon B@F
ydrogen $?F
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-e know that,
$Kg of carbon re'uires B> Kg of oxygen for the complete combustion.
$Kg of carbon sulphur re'uires $ Kg of *xigen for its complete combustion.
6#rom eat Jower %ngineering&"alasundrrum7
Therefore,
The total oxygen re'uires for complete combustion of $ Kg of fuel
Y 6B>c7 V 6>7 V 4Z Kg
=ittle of oxygen may already present in the fuel, then the total oxygen re'uired for
complete combustion of Kg of fuel
X Y 6B>c7 V 6B7 V 4 Z & *[ Kg
3s air contains +>F by weight of *xygen for obtain of oxygen amount of air
re'uired $88+> Kg
inimum air re'uired for complete combustion of $ Kg of fuel
6$88+>7 X Y 6B>c7 V V 4Z & *[
Kg
4o for petrol $Kg of fuel re'uires 6$88+>7 X Y 6B>c7 x 8.B@ V 6B x
8.$?7 Z [
$?.B? Kg of air
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3ir fuel ratio mm $?.B?$
$?.B?
m $?.B? m&&&&&&&&&&&&&&&&&&&&&&&&&&
6+7
4ubstitute 6+7 in 6$7
$.8$>+; x $88 >.B$$>? 6$?.B? m7 V =>+?.8+ m
m $.QR$ x $8KgCycle
ass of fuel flow per cycle $.QR$ x $8Kg cycle
Therefore,
ass flow rate of the fuel for +;88 9J
Y6$.QR$ x $87>@88Z x 6+;88+7 x @8
>.Q>$ x $8Kgsec
C$()2($%"o# o* )$(or"*") 5$(2e:
"y Delong/s formula,
igher Calorific Aalue >>B88 C V $??888 V R+Q8 4
6>>B88 x 8.B@7 V 6$??888 x 8.$?7 V 8
CA ?R++B KWKg
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=ower Calorific Aalue CA 6Rx +??+7
?R++B Y6R x 8.$?7 x +??+Z
?@$;$.8B KWKg
=CA ?@.$;$ WKg
F"#,"#. C $#, C5 *or %'e m"4%2re:
-e know that,
3ir contains QQF 2and +>F *by weight
"ut total mass inside the cylinder mV m
+.@; x $8V $.QR$ x $8Kg
+.B+R$ x $8Kg
6$7 -eight of nitrogen present QQF 8.QQ Kg in $ Kg of air
:n +.@; x $8Kg of air contains,
8.QQ x +.@; x $8Kg of 2
+.8?8; x $8Kg
Jercent of 2present in the total mass
6+.8?8; x $8+.B+R$ x $87
Q+.$+; F
6$7 Jercentage of oxygen present in $ Kg of air is +>F
Jercentage of oxygen present in total mass
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68.+> x +.@; x $876+.B+R$ x $87
+$.;? F
6+7 Jercentage of carbon present in $ Kg of fuel B@F
Jercentage of carbon present in total mass
68.B@@ x $.QR$ x $876+.B+R$ x $87
;.???F
6>7 Jercentage of ydrogen present in $ Kg of fuel $?F
Jercentage of ydrogen present in total mass
68.$? x $.QR$ x $876+.B+R$ x $87
8.BB@ F
Total Cp of the mixture is msi Cpi
Cp 68.Q+$+; x $.8?>7 V 68.+$;? x 8.R$>7
V 68.;???? x 8.Q7 V 6B.B@ x $8x $?.+;Q7
Cp $.$$>B KWKg.K
Cv msi Cvi
68.Q+$+; x 8.Q?;7 V 68.+$;? x 8.@;>7
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V 68.8;??? x 8.;?B@7 V 6B.B@ x $8x $8.$>>>7
8.B KWKg.K
63ll Cvi, Cpi values of corresponding components are taken from clerks table7
n #or the mixture 6CpCv7
$.$$8.B
n $.>B
Pre!!2re $#, %emer$%2re $% 5$r"o2! PH:
J $.8$>+; x $88 bar
$.8$>+; bar
T >8C >8> K
JJ 6r7 n
-here,
J $.8$>+; bar
r @.@
n $.>B
J $>.@RB bar
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T 6r7 nx T
-here,
T >8> K
T @+8.@B K
>
P =
8
0
V
eat 4upplied by the fuel per cycle
1 Cv
$.QR x $8x ?@$;$.8B
1 8.B+@; KWCycle
8.B+@; Cv 6T& T7
T ?+Q+.?; K
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6JA7 T 6JA7 T
-here,
A A
J 6Tx J7T
-here,
J R?.+Q bar
J J 6r7
J @.RQ> bar
T T 6r7 n
+8B@.$; K
POINT POSITION PRESSURE >;$r? TEMPERATURE
J*:2T&$ $.8$>+; >8 C >8> KJ*:2T&+ $>.@RB >?Q.@B C @+8.@B KJ*:2T&> R?.+Q >RRR.?; C ?+Q+.?; K J*:2T&? @.RQ> $B$>.$; C +8B@.$; K
DESIGN OF PISTON:
-e know diameter of the piston which is e'ual to ;8 mm
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T'")#e!! o* "!%o#:
The thickness of the piston head is calculated from flat&plate theory
-here,
t D 6>$@ x Jf7\
ere,
J & aximum combustion pressure $88 bar
f & Jermissible stress in tension >?.@@
2mm
Jiston material is aluminium alloy.
t 8.8;8 6>$@ x $88>?.@@ x $8$87\ x $888
$+ mm
N2m;er o* P"!%o# R"#.!:
2o. of piston rings + x D\
ere,
D & 4hould be in :nches $.R@B inches
2o. of rings +.B8;
-e adopt > compression rings and $ oil rings
T'")#e!! o* %'e r"#.:
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Thickness of the ring D>+
;8>+
$.;@+; mm
W",%' o* %'e r"#.:
-idth of the ring D+8
+.; mm
The distance of the first ring from top of the piston e'uals
8.$ x D
; mm
-idth of the piston lands between rings
8.Q; x width of ring $.BQ; mm
Le#.%' o* %'e "!%o#:
=ength of the piston $.@+; x D
=ength of the piston B$.+; mm
=ength of the piston skirt Total length Distance of first ring from top of
The first ring 62o. of landing between rings x
-idth of land7 62o. of compression ring x
-idth of ring7
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B$.+; ; + x $.BQ; > x +.;
@; mm
O%'er $r$me%er:
Centre of piston pin above the centre of the skirt 8.8+ x D
@; mm
The distance from the bottom of the piston to the
Centre of the piston pin \ x @; V $
>>.; mm
Thickness of the piston walls at open ends \ x $+
@ mm
The bearing area provided by piston skirt @; x ;8
>+;8 mm
ANDVANTAGE AND DISADVANTAGE
ADVANTAGES
%fficiency of the vehicle is improved
4mall modification is done in the vehicle
"attery efficiency and life time also increased
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DISADVANTAGES
$. 3dditional cost is re'uired
+. 3dditional space is re'uired to install this arrangement in vehicles
APPICATION
APPLICATIONS
3utomobile application
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