exhaust gas heat recovery power generation

8/12/2019 Exhaust Gas Heat Recovery Power Generation

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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#fig2


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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/Phonon


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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


46/52

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


47/52

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


48/52

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


49/52

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"#.:


50/52

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


51/52

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


52/52

DISADVANTAGES

$. 3dditional cost is re'uired

+. 3dditional space is re'uired to install this arrangement in vehicles

APPICATION

APPLICATIONS

3utomobile application

exhaust gas heat recovery power generation

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