Class no. # 18 Submitted to. S ir S haf -ud-din
Lab No. 1 Lay Lay out o the lab
Lab No. 1 Lay Lay out o the lab
Lab no. 2 •
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Basic parts o C !n"ine $or%in" o the internal combustion en"ine and its main parts.
&b'ecti(e To To get familiar with IC engine , its parts and working.
!n"ine Combustion of dierent components that arrange in such a way that it converts heat energy in mechanical energy. energy.
)ypes o en"ine C en"ine Combustion takes place internally
!C en"ine e.g Steam engine
Components o C en"ine 1.
Cylinder bloc%
Cylinder is the main body of IC engine. All other parts are assembled into it. it is made by high grade cast iron or by aluminum alloy. alloy.
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Cylinder head
The top end of cylinder is closed by means of removable removable cylinder head.
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Cylinder
urning of fuel occurs into it. !iston lies here and moves up " down. It is of cylindrical shape and is #tted in cylinder block.
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,iston
It is the moving component of the th e engine. It compresses the fuel mi$ture. And transfers the energy to crank shaft through connecting rods.
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,iston in"
%. Compr Compress ession ion rings& rings& 'orms a compact barrier against the fuel mi$ture not to leak it from cylinder. (. )il contr control ol rings rings&& It lubricates the cylinder wall and provides lubrication between piston and cylinder wall.
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Connectin" od
Connecting rod connects the piston to crankshaft. Together Together with crank shaft they form simple mechanism that converts reciprocating motion into rotary motion
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Cran% shat
asically it is a component attached with connecting rods , which converts to " fro motion into rotary motion .
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Cam shat
It is shaft in engine that contains series of cam for operating the engine valves mechanism and is driven by gears*timing belt*chain.
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Spar% ,lu"
!roduces a spark upon high voltage, which burns up the air fuel mi$ture
1. 3ip Stic% +easures the level of engine oil.
11. $ater ,ump & It Circulates the water for cooling purpose. enerally it is of centrifugal type.
12. &il ,umps Circulates engine oil under high pressure, when engine is running.
1*. 4ly $heel It is a rotary mechanical device which stores mechanical energy. Also it is having signi#cant moment of inertia which is provided when continuous energy source is disconnected.
1+. 5aniold +eans many folds, The main function of manifold is to supply the air fuel mi$ture and collects the e$haust gases e-ually form all cylinder. In an internal combustion engine two manifold are
used, one for intake and other for e$haust. They are usually made by aluminum alloy .
1. !n"ine (al(e It is located in cylinder head. Its purpose is to take air fuel mi$ture in and e$haust it upon burning.
1/. &il ,an ere all of engine oil stays when engine is in idle condition
10. ,iston ,in It connects the connecting rod and piston.
Lab no. * 3emonstration o our stro%e en"ine A our-stro%e en"ine /also known asour cycle0 is an internal combustion /IC0 engine in which thepiston completes four separate strokes while turning a crankshaft. A stroke refers to the full travel of the piston along the cylinder, in either direction. The four separate strokes are termed& %. nta%e& This stroke of the piston begins at top dead center /T.1.C.0 and ends at bottom dead center /.1.C.0. In this stroke the intake valve must be in the open position while the piston pulls an air2fuel mi$ture into the cylinder by producing vacuum pressure into the cylinder through its downward motion. (. Compression& This stroke begins at .1.C, or 3ust at the end of the suction stroke, and ends at T.1.C. In this stroke the piston compresses the air2fuel mi$ture in preparation for ignition during the power stroke /below0. oth the intake and e$haust valves are closed during this stage. 4. Combustion& This is the start of the second revolution of the four stroke cycle. At this point the crankshaft has completed a full 456 degree revolution. 7hile the piston is at T.1.C. /the end of the compression stroke0 the compressed air2fuel mi$ture is ignited by a spark plug /in a gasoline engine0 or by heat generated by high compression /diesel engines0, forcefully returning the piston to .1.C. This stroke produces mechanical work from the engine to turn the crankshaft.
!6haust& 1uring the exhaust stroke, the piston once again returns from .1.C. to T.1.C. while the e$haust valve is open. This action e$pels the spent air2fuel mi$ture through the e$haust valve.
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!6planation $hat 5a%es +-Cycle &(erhead 7al(e !n"ines 3ierent9 In overhead valve /)90 engines, the valves are positioned above the piston. The camshaft moves the valves through a tappet, pushrods and rocker arms. 82cycle )9 engines provide more e:cient combustion by allowing the air2fuel mi$ture to spread more evenly throughout the combustion chamber.
)he +-Stro%e System that ,o:er ;our Small !n"ine In order to power your e-uipment, the overhead valve engine completes a repeating 82step process detailed below .
!lement that
opens. This allows atmospheric pressure to force the air2fuel mi$ture into the cylinder bore as the piston moves downward..
Step 2 Compression Stro%e
Step * ,o:er Stro%e 7hen the piston reaches the top of its travel /top dead center0, it will be at its optimum point to ignite the fuel to get ma$imi=e power to your outdoor power e-uipment. A very high voltage is created in the ignition coil. The spark plug enables this high voltage to be discharged into the combustion chamber. The heat created by the spark ignites the gases, creating rapidly e$panding, super2heated gases that force the piston back down the cylinder bore. This is called the po:er stro%e.
Step + !6haust Stro%e 7hen the piston reaches bottom dead center again, the e$haust valve opens. As the piston travels back up the cylinder bore, it forces the spent combustion gases through the e$haust valve and out of the e$haust systems. As the piston returns to top dead center, the e$haust valve closes and the intake valve opens and the 82cycle engine process repeat. >ver repetition of the cycle re-uires two full rotations of the crankshaft, while the engine only creates power during one of the four strokes. To keep the machine running, it needs the small engine ?ywheel. The power stroke creates momentum that pushes the ?ywheel;s inertia keeps it and the crankshaft turning during the e$haust, intake and compression strokes.
Lab no. + 3emonstration o t:o stro%e en"ine &b'ecti(e To know about working of ( stroke engine.
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To know about relationship of stroke.
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)heoretical bac%"round the inlet and e$haust are timed, It means that the inlet and e$haust strokes are timed. ence the names given& two stroke engines uses two strokes, therefore a four stroke engine would use four distinct strokes. In a four stroke engine, the order of operation is as follows& Intake, Compression, Ignition, and >$haust. In a two stroke engine however, the strokes are called the !ower Stroke and the >$change Stroke. If we think in terms of a four stroke engine, there are two parts to the intake stroke In a four2stroke engine, each of the four essential steps of the power2producing cycle is given its own piston stroke& %0 Compression (0 !ower 40 >$haust 80 Intake
A two2stroke performs all the same steps, but in 3ust two piston strokes. The simplest two2strokes do this by using the crankcase and the underside of the moving piston as a fresh charge pump. Such engines carry the o:cial name @crankcase2scavenged two2strokes.
=p:ard stro%e • •
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!iston moves upwards Inlet valve opens and air fuel mi$ture is drawn into the chamber. >$haust and transfer valve remain closed. At the end of this stroke compression and suction is complete.
3o:n:ard Stro%e • • • •
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!iston moves downwards . 'irst e$haust past opens, followed by transfer. Combusted air fuel mi$ture e$hausts through e$haust past At the instant partially compressed air fuel mi$ture covers through transfer post. At the end power and e$haust stroke is completed
3isad(anta"es o t:o stro%e en"ine %. 2 Two2stroke engines dont live as long as four2stroke engines. The lack of a dedicated lubrication system means that the parts of a two2stroke engine wear2out faster. Two2stroke engines re-uire a mi$ of oil in with the gas to lubricate the crankshaft, connecting rod and cylinder walls. (. 2 Two2stroke oil can be e$pensive. +i$ing ratio is about 8 ounces per gallon of gas& burning about a gallon of oil every %,666 miles. 4. 2 Two2stroke engines do not use fuel e:ciently, yielding fewer miles per gallon. 8. 2 Two2stroke engines produce more pollution. B. 22 The combustion of the oil in the gas. The oil makes all two2 stroke engines smoky to some e$tent, and a badly worn two2 stroke engine can emit more oily smoke. 5. >ach time a new mi$ of air*fuel is loaded into the combustion chamber, part of it leaks out through the e$haust port
ue This is the most important reasons why people choose a 82 stroke engine. The two2stroke boasts its speed and power, but the four2stroke shows e$tra tor-ue. It is more reliable and -uitter. (. Last lon"er 'our stroke engines last longer and use much, much less oil. Compared to two2stroke engines, the four stroke engine is durable for use. The more times an engine goes around, the -uicker it will wear out. As (2strokes must rev to very high D!+ to make any power, most applications using them are geared toward maintaining that D!+. Thus, they can;t live as long as four2stroke engine.
4. un much cleaner than 2 stro%es A ( stroke makes a lot of e$haust smoke because it burns oil mi$ed with fuel. )n the contrary, four2stroke engines have a dedicated oiling system that;s kept largely separate from the combustion chamber, which help to ensure that the only thing burning in the engine is gasoline.
3isad(anta"es o our stro%e %. Complicated Two2stroke engines do not have valves, simplifying their construction. owever, there are more parts to worry about in a four2stroke engine which results in harder to troubleshoot. (. ?al as po:erul as t:o stro%e en"ines 'or e-uivalent engines, the four stroke ones #re once every two revolutions, while two stroke engines are more powerful because every revolution of the engine includes a power stroke. 4. 5ore e6pensi(e than 2 stro%e A four2stroke engine is much more e$pensive and comple$ than a two2stroke one. It has more complied with more parts so they often re-uire repairs more often and it is usually more e$pensive.
Lab no. 3emonstration o diesel and petrol en"ine &b'ecti(e To know about working of diesel and petrol engine. To know about dierence between
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Basic dierences
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(. 4.
Criteria o comparison 7orking Cycle 'uel used Compression Datio
,etrol !n"ine Constant volume )tto cycle !etrol E&%
3iesel !n"ine Constant pressure 1iesel cycle 1iesel ((&%
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'uel supply
B.
Spark ignition
5. G. E.
Initial cost Dunning +aintenance cost Chances of pre2ignition Combustion oise 'ield of application !ressure 7eight >:ciency >nergy content !ower K tor-ueLD!+ Auto2ignition temperature C)( emission
H. %6. %%. %(. %4. %8. %B. %5. %G. %E. %H.
Carburetors are used !lug is used
Fess +ore Fess but fre-uent +ore
'uel in3ectors are used eat of compression is used +ore Fess +ore but not fre-uent Fess
Smooth Fess Fight duty
Irregular +ore eavy duty
Fess Fess 4BJ 48.5 +<*litre
+ore +ore 8BJ 4E.5 +<*litre
Duns at higher D!+ (85MC
Duns at higher D!+ (%6MC
Fower than diesel.
+ore than gasoline/petr ol0. 1iesel fuel produces appro$imatel y %4J more C)( gas per gallon of fuel burned, compared to gas /petrol0
(6.
9iscosity
o change
(%.
1angerous
its dangerous due to its volatility
engines increase at lower temperature s on2 volatile , so not dangerous
$or%in" o ,etrol en"ine 4our Stro%e ,etrol !n"ine The cycle of operation in a four stroke petrol engine is completed in two revolutions of crank shaft or four strokes of piston. Stroke is de#ned as the distance traveled by the piston from one of the dead centers to the other dead centre. It is also e-ual to two times the crank radius. ence in a four stroke engine work is obtained only during one stroke out of the four strokes of the piston re-uired to complete one cycle. This engine works on )tto or constant volume cycle. %. Suction stro%e& To start with the piston is at or very near T.1.C. and the inlet valve is open and e$haust valve is closed. As the piston moves from T.1.C. to .1.C. rarefaction is formed in the cylinder which causes the charge to rush in and #ll the space vacated by the piston. The charge consists of a mi$ture of air and petrol prepared by the carburetor. The admission of charge inside the engine cylinder continues until the inlet valve closes at .1.C.
(. Compression stro%e& oth the valves are closed and the piston moves from .1.C. to T.1.C. The charge is compressed up to a compression ratio of B&% to H&% and pressure and temperature at the end of compression are about 5 to %( bar and (B6N C to 466N C respectively. 4. Working, Power or Expansion stroke & 7hen the piston reaches T.1.C. position, or 3ust at the end of compression stroke, the charge is ignited by causing an electric spark between the electrodes of a spark plug, which is located some where in the walls of cylinder head. 1uring combustion the chemical energy of fuel is released and there is rise in temperature and pressure of gases. The temperature of gases increases to about %E66N C to (666N C and the pressure reaches 46 to 86 bar. Op till now the volume of gases formed however remains almost constant with both valves closed. ow the combustion products e$pand and push the piston down the cylinder. The reciprocating piston motion is converted into rotary motion of crankshaft by a connecting rod and crank. 1uring e$pansion the pressure drops due to increase in the volume of gases and absorption of heat by cylinder walls. 4. !6haust stro%e & Theoretically e$haust valve opens at the end of working stroke when the piston is at .1.C. position. ut actually e$haust valve begins to open when about EB J of the working stroke is completed. A pressure of 8 to B bar at this instant forces about 56 J of the burnt gases into the e$haust manifold at high speed. The remaining burnt gases are cleared o the swept volume when the piston moves from .1.C. to T.1.C. 1uring this stroke the pressure in side the cylinder is slightly above the atmospheric value. Some of the burnt gases are however left in the clearance space. The e$haust valve closes shortly after the piston reaches T.1.C. The inlet valve opens slightly before the end of e$haust stroke and the cycle repeats
$or%in" o 3iesel en"ine 4our Stro%e 3iesel !n"ine
The cycle of operation in a four stroke diesel engine is completed in two revolutions of crankshaft or four strokes of piston using diesel oil as fuel. This engine works on diesel cycle. %. Suction Stro%e Starting of engine is done by an electric motor or manually. In both cases the energy is supplied to the engine. In this stroke the inlet valve opens and the outlet valve remains closed. !iston moves from T.1.C. to .1.C. and in this way a vacuum is created in the cylinder. This vacuum is #lled by air alone and piston reaches to .1.C. (. Compression Stro%e& oth valves are closed. This time piston moves from .1.C. to T.1.C. Air is compressed in this stroke up to a compression ratio of %B&% to ((&% and a very high temperature
is produced due to high pressure. The high temperature is the only cause of combustion of the fuel. The piston takes the power in this stroke from the ?ywheel. 1uring this stroke the pressure and temperature attain a high value of 86 to 56 bar and 566N C to G66N C 4. $or%in" Stro%e& At the end of compression stroke or when the piston reaches the T.1.C. position, a #ne spray of diesel is in3ected in the cylinder through in3ector. The fuel burns by the heat of compressed air and due to its burning the power is produced. This power pushes the piston downward i.e. from T.1.C. to .1.C. The e$cess energy of the piston is stored in the ?ywheel of the engine, which is further used for the remaining three strokes of the engine. The reciprocating motion of the piston is converted into the rotary motion of the crankshaft by connecting rod and crank. 1uring e$pansion the pressure drops due to increase in volume of gases and absorption of heat by cylinder walls. 8. !6haust Stro%e& The e$haust valve begins to open when about EBJ of the working stroke is completed. The force of piston
coming from .1.C. to T.1.C. forces the burnt gases into the e$haust manifold. Some of the gases are forced out due to higher pressure in the cylinder and the remaining gases are forced out by the piston. Some of the burnt gases are however left inside the clearance space. The e$haust valve closes shortly after T.1.C. The inlet valve opens slightly before the end of e$haust and in this way the cycle repeats.
Lab no. / 3emonstration o i"nition system@ o an en"ine. &b'ecti(e To learn what is the ignition system and its components. To learn how these components combine together to form a spark.
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)heoretical Bac%"round The system which ignites the air fuel mi$ture to form a spark, due to which power is produced and component of engine runs.
4unction o i"nition system There are two functions of ignition system. To control spark and to control its timings. To increase voltage from %(9 to (6P9.
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)ypes o i"nition system • •
Contact point ignition system >lectronic ignition system
Components o contact point i"nition system Battery The battery is the source of electrical energy needed to operate the ignition system. The battery stores and produces electricity through chemical action. 7hen it being charged, it converts electricity into chemical energy. 7hen it is discharged /producing current0, the battery converts chemical energy into electricity.
"nition S:itch. The primary circuit starts at the battery and ?ows to the ignition switch. It controls the ?ow of electricity across the terminals.
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"nition Coil. The primary circuit leads from the ignition switch to the ignition coil. An ignition coil is actually a step up transformer and electromagnet having two types of windings .
I. II.
!rimary windings Secondary windings that is capable of increasing battery voltage to as much as %66,666 volts, although most coils produce about B6,666256,666 volts.
Contact brea%er A contact breaker /or QpointsQ0 is a type of electrical switch, and the term typically refers to the switching device found in the distributor of the ignition systems of spark2ignition internal combustion engines. The purpose of the contact breaker is to interrupt the current ?owing in the primary circuit of the ignition coil.
C&N3!NS! The condenser, also known as a capacitor, is wired in parallel with the contact points and grounded through the distributor housing. The condenser prevents arcing or burning at the distributor contact points when the points are #rst open. The condenser provides a place where current can ?ow until the contact points are fully open.
Spar% plu" It receives a high voltage spark from secondary coil through rotor and outer terminal having two electrodes I. II.
Control electrodes round electrodes
3istributor As name indicates, it distributes electric current. It has two parts.
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3istributor C<5 3istributor rotor They transfer voltage from central terminal to outer terminal.
Contact points The contact points used on older vehicles were a simple mechanical way of making and breaking the coil primary circuit. It also distributes the high voltage surges to spark plug in correct order.
)he t:o types are
4i6ed point The stationary piece is grounded through the distributor contact point mounting plate. This section does not more other than for an initial point ad3ustment.
5o(able point The second piece is the movable contact point. It is pivoted on a steel post. A #ber spring presses the movable contact arm against the stationary unit, causing the two contact points to touch each other.
Lab no. 0 3emonstration o coolin" system o an !n"ine &b'ecti(e %. To keep the engine running at its most e:cient temperature. (. To know about working of water cooling system. 4. To know about working of air cooling system.
)heoretical bac%"round 1uring combustion process engine produces tremendous amount of heat. That amount of heat is dissipated in dierent areas. • •
/(62(B0J of heat is used in brake power /4624B0J of heat is e$tracted by cooling system
Demaining amount of heat is dissipated in friction and e$haust gases.
)ypes o coolin" system %. Air cooling system& (. 7ater cooling system& •
Components o air :ater system )he adiator
The radiator core is usually made of ?attened aluminum tubes
with aluminum strips that =ig=ag between the tubes. These #ns transfer the heat in the tubes into the air stream to be carried away from the vehicle. )n each end of the radiator core is a tank, usually made of plastic that covers the ends of the radiator The tanks, whether plastic or brass, each have a large hose connection, one mounted towards the top of the radiator to let the coolant in, the other mounted at the bottom of the radiator on the other tank to let the coolant back out. )n the top of the radiator is an additional opening that is capped o by the radiator cap.
)hermostat The thermostat regulates the ?ow of coolant into the engine keeping it at its optimum operating temperature. The thermostat is closed when the engine is cold. As the engine heats up, the thermostat opens and allows coolant from the radiator to circulate. It is having wa$ pellet , which melts and valve opens.
$ater ,ump The water pump is considered the Rheart; of the cooling system and is usually located on the front of the cylinder block. A hose carries cooled coolant from the radiator to the water pump. A belt or chain turns the water pump shaft and coolant enters the center of the pump. The water pump has fan2like blades on an impeller that spins, creating centrifugal force, moving the li-uid outward. Coolant is routed through the engine, cylinder heads and intake manifold by way of water 3ackets. The coolant then absorbs heat from the engine components and, once hot, leaves the engine and enters the radiator once again to begin the ne$t cooling cycle.
adiator Cap It is having a spring valve loaded mechanism. The radiator cap is responsible for maintaining the proper amount of cooling system pressure. If the amount increases above the set pressure point, a spring2loaded valve in the cap releases e$tra pressure.
$ater Aac%et These are passage inside engine which allows coolant to ?ow inside engine, and further by coolant heat is e$tracted
4ans 1raws the air inside the engine by passing air through radiator which cool down the temperature of coolant.
Lab no. 8 3emonstration o lubrication system &b'ecti(es >$plain the purpose of the lubrication system. 1escribe oil ratings Identify the main components of the lubrication system
System Components Components& )il pressure switch Fifter*buckets !iston 3ets Sump*pan !ickup tube )il pump )il #lter
7iscosity If the oil is too thin/has very low viscosity0 it will be forcedout from between the moving parts, resulting in rapid wear.
If the oil is too thick/has very high viscosity0it will ?ow veryslowly to engine parts, especially when the engine and the oilare cold, resulting in rapid wear.
7iscosity nde6is the measure of how much the viscosity ofan oil changes with temperature. /(6 709iscosity number is set by Sngineers0
Sin"le (iscosity oilsSA> B7, SA> %67 /7inter0 andSA> (6, SA>46 U /Summer0
5ultiple (iscosity oilsSA> %67246. This means that the oil is same as SA> %67 when coldand SA>46 when hot. The higher the number the higher the viscosity/thickness0of oil •
,arts o &il ,umps 1riven by camshaft, crankshaft /Darelyrebuild by an auto technician0
otor ,ump/Two star shaped rotorspumps the oil0
ear oil ,ump
&il ,an Stores the oil and helps in cooling the oil!an gasket splits if over tightened.
&il ,ressure ndicator Fight or a auge The light turns on or gauge reads low when the pressure drops below %6psi.
Common causes o lo: oil pressure are Lo: oil le(el $orn out pump Fow oil pressure Safety systemwill shuts down the car by cutting the ignition System/Spark0. ood oil pressure is +-/ psi.
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&il 4ilter #lters the oilSome particles are too small for the #lter !lement/paperin the #lter0 to trap.
Lab no. B
)?!&&)C
?;3<=LC B
the front ones only. Onder heavy braking, so much weight may come o the rear wheels that they lock, possibly causing a dangerous skid. 'or this reason, the rear brakes are deliberately made less powerful than the front. +ost cars now also have a load2sensitive pressure2limiting valve. It closes when heavy braking raises hydraulic pressure to a level that might cause the rear brakes to lock, and prevents any further movement of ?uid to them. Advanced cars may even have comple$ anti2lock systems that sense in various ways how the car is decelerating and whether any wheels are locking. Such systems apply and release the brakes in rapid succession to stop them locking.
$&DN ,NC,L! 7orking principle of a hydraulic braking system is pascal law that is applied pressure is transmitted into all directions uniformly.
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B
);,!S &4 B
metal disc, illuminating a warning light on the instrument panel.
3=5 Bach brake shoe has a pivot at one end and a piston at the other. A leading shoe has the piston at the leading edge relative to the direction in which the drum turns. The rotation of the drum tends to pull the leading shoe #rmly against it when it makes contact, improving the braking eect. Some drums have twin leading shoes, each with its own hydraulic cylinderV others have one leading and one trailing shoe 2 with the pivot at the front. This design allows the two shoes to be forced apart from each other by a single cylinder with a piston in each end. It is simpler but less powerful than the two2leading2shoe system, and is usually restricted to rear brakes. In either type, return springs pull the shoes back a short way when the brakes are released. Shoe travel is kept as short as possible by an ad3uster. )lder systems have manual ad3usters that need to be turned from time to time as the friction linings wear. Fater brakes have automatic ad3ustment by means of a ratchet. 1rum brakes may fade if they are applied repeatedly within a short time 2 they heat up and lose their e:ciency until they cool down again. 1iscs, with their more open construction, are much less prone to fading.
Lab no 1 4=!L S;S)!5 &4
)?!&)C
);,!S &4 4=!L S;S)!5 •
'O>F SO!!FX SXT>+
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'O>F +>T>DI SXST>+
C&5,&N!N)S &4 4=!L S;S)!5 All internal combustion engines need three things to run... Air, 'uel and Spark. The fuel system is critical in storing and delivering the gasoline or diesel fuel your engine needs to run. Think of it as your vascular system, with a heart /fuel pump0, veins /fuel lines0 and kidneys /#lter0. A failure in any of these fuel system components has the same devastating eects as in your body. Fets get a little more in depth with each part...
4uel tan% asically a holding tank for your fuel. 7hen you #ll up at a gas station the gas travels down the #ller tube and into the tank. In the tank there is a sending unit which tells the gas gauge how much gas is in the tank. In recent years the gas tank has become a little more complicated, as it now often houses the fuel pump and has more emissions controls to prevent vapors leaking into the air.
4uel pump )n newer cars the fuel pump is usually installed in the fuel tank. )lder cars have the fuel pump attached to the engine or on the frame rail between the tank and the engine. If the pump is in the tank or on the frame rail then it is electric and is run by your cars battery. 'uel pumps mounted to the engine use the motion of the engine to pump the fuel, most often being driven by the camshaft, but sometimes the crankshaft.
4uel flter Clean fuel is critical to engine life and performance. 'uel in3ectors and carburetors have tiny openings which clog easily so #ltering the fuel is a necessity. 'ilters can be before or after the fuel pump, sometimes both. They are most often made from a paper element, but can be stainless steel or synthetic material and are designed to be disposable in most cases. Some performance fuel #lters will have a washable mesh, which eliminated the need for replacement.
4uel in'ectors +ost domestic cars after %HE5 and earlier foreign cars came from the factory with fuel in3ection. Instead of a carburetor to mi$ the fuel and air, a computer controls when the fuel
in3ectors open to let fuel into the engine. This has resulted in lower emissions and better fuel economy. The fuel in3ector is basically a tiny electric valve which opens and closes with an electric signal. In the picture below you can see the in3ectors towards the outer part of the intake. y in3ecting the fuel close to the cylinder head the fuel stays atomi=ed / in tiny particles 0 so it will burn better when ignited by the spark plug.
Carburetors A carburetor take the fuel and mi$es it with air without computer intervention. 7hile simple in operation, they tend to need fre-uent tuning and rebuilding. This is why most new cars have done away with carburetors in favor of fuel in3ection.
)hrottle 7al(e It is a butter?y type valve use to regulate the ?ow of ?uid.
4=!L S;S)!5 &4
Lab no. 11 Carburetor Circuit Carburetor A carburetor /American and Canadian spelling0, carburator, carburettor, or carburetter /Commonwealth spelling0 is a device that blends air and fuel for an internal combustion engine.
dle System The carburetor idle system provides the air2fuel mi$ture at speeds below appro$imately E66rpm or (6 mph/62860 7hen the engine is idling, the throttle is almost closed Air ?ow through the air horn is restricted to produce enough vacuum in the venture. Since venture vacuum is too low to pull fuel from the main discharge tube, the high intake manifold vacuum >F)7 the throttle plate and the idle circuit are used to feed fuel into the air horn. The fundamental parts of the carburetor idle system include a section of the main discharge tube, a low2 speed 3et, an idle air bleed, a bypass, a idle passage, an economi=er, an idle screw port, and an idle mi$ture screw.
Lo: speed circuit The low speed circuit controls all the ?ow of fuel going into the engine during idle and light load speeds. It partially controls the ?ow for light load speeds, between twenty and thirty miles per hour. Above thirty miles per hour, it stops operating completely. Fow speed systems in general, consist of the low speed 3et, economi=er, air bleed, idle passage, upper idle port and the lower idle port, which contains idle ad3usting screw or needle.
?i"h speed Circuit aving two high speed systems operating together in a dual carburetor, means proper balance must be maintained between them, for all high sped engine operation. To insure this proper balance and operation, main metering 3ets should be installed in matched sets /also metering rods on Carter0 and main no==les should be carefully e$amined for wear or damage. )n Carter 1ual carburetors, the mechanism that operates the metering rods and anti2percolating valves should be thoroughly checked for correct operation. Any changes in the high speed system must be the same for each half of the carburetor. )ne half cannot be changed without the other and still have correct carburetor and engine operation.
Lab no. 12 3!5&NS)<)&N &4 )
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In motor vehicle applications, the transmission will generally be connected to the crankshaft of the engine. The output of the transmission is transmitted via driveshaft to one or more dierentials, which in turn drive the wheels.
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=ni(ersal Aoints
Oniversal 3oint is also known as cardan 3oint and O 3oint. This 3oint is the point of connection in a sti rod which enables the rod to turn in any desired direction in auto transmission system. In other words universal 3oint is a 3oining link between two shafts that are in a changing position. These automotive transmission parts are one of the earliest form of ?e$ible couplings that have two shaft yokes located at H6 degrees angle to each other and a four point cross that fasten the yokes. •
)ransmission <6les
Transmission a$les are the shafts usually rods or bars, which are used for providing support to dierential shafts and wheels in order to actuate a vehicle. These transmission parts consists of spline at one end and ?ange at the other end. oth of these components are used for holding tightly the wheel studs. +ore precisely, transmission a$le is the metal based shaft to which wheels, brakes and other automotive suspension parts are connected. •
&utput Shat&
)utput shaft is a rotatable cylindrical bar that is used in automotive transmission systems for transmitting tor-ue from a device. The basic parts of an output shaft are plug2in, spline and tapered tool #ttings. These automotive transmission parts also called as drive shaft or slow speed shaft are the essential elements of speed reducer, which is a:$ed to driven e-uipment. •
3ierential
1ierential is a device or an e-uipment that comprises of gears which are attached to the drive shaft and allows the wheels to rotate at varied speeds. The main purpose of creating this mechanism is for driving wheels with alike force thereby allowing them to turn at dierent speeds. +ore speci#cally, dierential balances the power between the left and right drive wheels at the time of cornering i.e. when inside wheels move more slowly than the outside wheels. •
ear Shiters&
An essential part of automotive transmission or auto transmission system, gear shifter is basically the mechanical component that is used for controlling and operating the gearing mechanism and choosing the suitable gear ratio. These are the critical parts of the gearbo$ that usually comprises of shift forks, shift knobs and shift lever. Shifter forks used in automobile transmission systems are a:$ed to a cam and shaft assembly. 7hile the shift levers are attached either to a control on the steering column or a shift stick placed on the ?oor. •
Clutch
Clutch is basically a lever or pedal that is used for changing gears in an automobile. The clutch used in automobile is a device which helps in making the vehicle move smoothly from a standstill position, accelerate it with dierent gears and bring it back to its original standstill position. The key use of the clutch is to manage the smooth start, acceleration and control the mileage of an automobile. Osually 3udder and heat resistant materials are used for making automotive clutches. Stainless steel, carbon, iron, copper, bron=e, brass etc are widely used for manufacturing automobile clutch.
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