This document is an industrial training report submitted by Naman Mishra to Bharat Coking Coal Limited (BCCL). BCCL is a subsidiary of Coal India Limited that operates coal mines and washeries in India. The report provides an overview of BCCL and its Central Excavation Workshop in Sinidih, which repairs and maintains heavy earthmoving equipment. It also describes the main engine brands serviced at the workshop, and includes an index of topics to be covered in the report such as types of engines, diesel engine parts and their functions, engine disassembly, and transmission systems.

2. AN INDUSTRIAL TRAINING REPORT
CONDUCTED AT
BHARAT COKING COAL LTD.
(A Subsidary of Coal India Ltd.)
(SINIDIH CENTRAL EXCAVATION WORKSHOP-DHANBAD,JHARKHAND)
(ISO 9001:2008,ISO 14001:2004 & AS 4801/OHAS 18001)
SUBMITTED BY:
NAMAN MISHRA
ROLL NO.-1604540031
MECHANICAL ENGINEERING
HARCOURT BUTLER TECHNICAL UNIVERSITY, KANPUR-208002
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3. ACKNOWLEDGEMENT
I would withhold this opportunity to express my profound gratitude and deep regards to
Mr. Anuj Kumar ( Deputy G.M. EXCAVATION )
for his exemplary guidance, monitoring and constant encouragement throughout the training. The blessing, help and guidance given
by him time to time shall carry me a long way in the journey of life on which I am about to embark.
I also take this opportunity to express a deep sense of gratitude to
Mr. S. P. Sinha (Chief Manager EXCAVATION) ,
Mr. T. K. Jas (Chief Manager TRANSMISSION)
and all the Engineers and working staff of the workshop (BCCL), from whom the valuable information and guidance, helped me in
completing this task at various stages.
I am obliged to staff members of Bharat Coking Coal Ltd. for the valuable information provided by them in their respective fields. I
am grateful for their cooperation during the period of my training.
Lastly, I thank the almighty, my parents and friends for their constant encouragement without which this assignment would not have
been possible.
NAMAN MISHRA
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4. DECLARATION
I; NAMAN MISHRA; a student of MECHANICAL ENGINEERING of HARCOURT BUTLER
TECHNICAL UNIVERSITY, KANPUR-208002 declare that this REPORT has been done after the
completion of my INDUSTRIAL TRAINING at CENTRAL EXCAVATION WORKSHOP
SINIDIH, DHANBAD-828128. It has not been altered or corrected as a result it may contain
errors and omissions.
NAMAN MISHRA
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5. INDEX
1.ABOUT THE COMPANY:.......................................................................................................................................................
2.CENTRAL EXCAVATION WORKSHOP,SINIDIH ......................................................................................................................
3. ENGINE :-­­ .............................................................................................................................................................................................................9
4. Classificationof Engines:..................................................................................................................................................
5. What are Compression-­­ignition Engines ? .......................................................................................................................
6. Parts of the Diesel Engine anditsfunction:.......................................................................................................................
6.1 Cylinderblock:...........................................................................................................................................................
6.2 CylinderHead:............................................................................................................................................................
6.3 Crankcase:..................................................................................................................................................................
6.4Piston,connectingrod,pistonringsand gudgeonpin:..............................................................................................
6.5 Crankshaft:.................................................................................................................................................................
6.6 Flywheel:....................................................................................................................................................................
6.7 Liners:.........................................................................................................................................................................
6.8 Gaskets:......................................................................................................................................................................
6.9 Rockerarm:................................................................................................................................................................
6.10 Oil Pump:.................................................................................................................................................................
6.11 Exhaustmanifoldwithturbocharger:....................................................................................................................
6.12 Water Pump:...........................................................................................................................................................
6.13 Oil Filters:................................................................................................................................................................
6.14 Sump :......................................................................................................................................................................
7. Dis-­­assembly of diesel engine :-­­ .......................................................................................................................................
7.1 Engine removal :-­­ .......................................................................................................................................................
7.2 Engine disassembly:-­­.................................................................................................................................................
8. Testing..............................................................................................................................................................................
9. Transmission:...................................................................................................................................................................
10. Purpose of an automatictransmission:..........................................................................................................................
11. How automatictransmission works:..............................................................................................................................
Nowhowdoesthisall work?...............................................................................................................................................
Planetarygearing.................................................................................................................................................................
MACHINES& TOOLS USED DURING THE TRAININGPERIOD
Bibliography.............................................................................................................................................................................
1.
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6. 1.ABOUT THE COMPANY :
Bharat Coal Coking Ltd. (BCCL) is a subsidiary of Coal India Limited with its headquarters in Dhanbad, India .
It was incorporated in January, 1972 to operate coking coal mines (214 in number) operating in the Jharia and
Raniganj Coalfields, taken over by the government of India on 16th Oct, 1971.
The company operates 81 coal mines which include 40 underground, 18 opencast and 23 mixed mines at April
2010. The company also runs six coking coal washeries, two non-coking coal washeries, one captive power
plant (2 by 10 megawatt), and five by-product coke plants. The mines are grouped into 13 areas for
administration purposes.
BCCL is the major producer of prime coking coal (raw and washed) in India. Medium coking coal is produced
in its mines in Mohuda and Barakar areas. In addition to production of hard coke, BCCL operates washeries,
sand gathering plants, a network of aerial ropeways for transport of sand, and a coal bed methane based power
plant in Moonidih.
CURRENT SITUATION:
Bharat Coking Coal Limited gave an annual coal production of around 30 million tonnes in 2010-­­11 with a turnover of
INR 11,505 crores. The company came out of the purview of BIFR (Board for Industrial and Financial Reconstruction) in
2013 and has manpowerof about49,901.
There are 12 areas in BCCL:
Administrative area Name
Area No 1 Barora Area
Area No 2 Block II Area
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7. Area No 3 Govindpur Area
Area No 4 Katras Area
Area No 5 Sijua Area
Area No 6 Kusunda Area
Area No 7 Putki Balihari Area
Area No 9 Bastacolla Area
Area No 10 Lodna Area
Area No 11 Eastern Jharia Area
Area No 12 Chanch Victoria Area
Area No 13 Western Jharia
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8. CENTRAL EXCAVATION WORKSHOP, SINIDIH
The Workshop consists of Engine section, Transmissions section, Machine Shop, Electrical section and store. It
deals with the repairing, maintenance and overhauling of the company’s heavy Earth movers like dozers, pay
loaders, hallpacks, dumpers shovels, drills etc. engines and transmission.
The Workshop is well equipped with modern machincery like overheaded cranes, crankshaft grinding machines
and advanced tools to carry out the repair and maintainance work.
Figure 1: VIEW OF THE WORKSHOP
The workshop consists of series of engines and transmissions. The main brands of the engines are as follow :-
1. CUMMINS
2. CAT
3. KOMATSU
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10. 1.ENGINE:-­­
An engine is a machine designed to convert energy into useful mechanical motion. Heat engines,
including internal combustion engines and external combustion engines (such as steam engines) burn a fuel
to create heat which then produces motion.
"Engine" was originally a term for any mechanical device that converts force into motion. Most mechanical
devices invented during the industrial revolution were described as engines—the steam engine being a notable
example.
In modern usage, the term engine typically describes devices, like steam engines and internal combustion
engines, that burn or otherwise consume fuel to perform mechanical work by exerting a torque or linear force to
drive machinery that generates electricity, pumps water, or compresses gas. In the context of propulsion
systems, an air-breathing engine is one that uses atmospheric air to oxidise the fuel rather than supplying an
independent oxidizer, as in a rocket.
When the internal combustion engine was invented, the term "motor" was initially used to distinguish it from
the steam engine—which was in wide use at the time, powering locomotives and other vehicles such as steam
rollers. "Motor" and "engine" later came to be used interchangeably in casual discourse. However, technically,
the two words have different meanings. An engine is a device that burns or otherwise consumes fuel, changing
its chemical composition, whereas a motor is a device driven by electricity, which does not change the chemical
composition of its energy source.[3]
A heat engine may also serve as a prime mover ,a component that transforms the flow or changes in pressure of
a fluid into mechanical energy.
An automobile powered by an internal combustion engine may make use of various motors and pumps, but
ultimately all such devices derive their power from the engine. Another way of looking at it is that a motor
receives power from an external source, and then converts it into mechanical energy, while an engine creates
power from press.
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11. ClassificationofEngines:
1. Classification on the basis of fuel used:
(a) Petrol(gasoline) engine
(b) Diesel Engine
(c) Gas Engine
2. Classification on the basis of no. of strokes:
(a) Four stroke engine
(b) Two stroke engine
(c) Hot spot ignition engine
3. Classification on the type of ignition:
(a) Spark ignition engine
(b) Compression ignition engine
4. Classification on the basis of arrangement of cylinders:
(a) Vertical engine
(b) Horizontal engine
(c) Radial engine
(d) V-engine
5. Classification based on Valve arrangement:
(a) L-head arrangement
(b) I-head arrangement
(c) F-head arrangement
(d) T-head arrangement
6. Classification based on type of cooling:
(a) Air cooled engine
(b) Water cooled engine
(c) Evaporation cooling engine
The workshop mainly deals with Compression ignition engines that uses diesel as its fuel , and inline cylinder
arrangements and v-type cylinder arrangements are mostly repaired and maintained here in the workshop.
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12. 1. What are Compression-­­ignitionEngines ?
Compression-ignition (CI) engines, also known as diesel engines, are ubiquitous prime movers with many
commercially important applications (motor vehicles, marine, locomotive, off-highway mobile
machinery).Rudolf Diesel in Germany invented and ran his first CI engine in 1893, intended to replace lower-
efficiency external combustion steam engines for stationary uses.
A form of internal-combustion heat engine that converts fuel energy to useful mechanical work, the CI engine
relies on high compression ratios (15 to 25:1, with most around 16-20:1) to heat the intake air by compression
to around 550 C (or 1,022 F) to ignite fuel typically injected just before top dead center (TDC) of the piston
stroke. CI engines will run on a variety of hydrocarbon fuels, from aromatics such as gasoline to heavy carbon-
rich fuel oil, as well as biological-based fuels (vegetable oils). For motor vehicle CI engines today, all injection
is direct into the combustion chamber by an electronically-controlled very precise valve (which varies opening
timing/duration) with either electric solenoid or piezoelectric actuators. The preferred fuel injection layout today
for highway diesels is common rail, which relies on a pump to pressurize fuel in a common manifold or rail
feeding all injectors. In other CI engine applications (such as off-road machinery), unit injectors with a
mechanical pump for each cylinder are used.
The typical injection pressures today are around 2000 bar (1 bar = 1 atmosphere = 14.6 psi), heading toward
2500 bar, with experimental installations running at 3000 bar. At such pressures, the fuel spray becomes quickly
well atomized into tiny droplets that first vaporize on their surfaces in the hot air, and then ignite. When the fuel
is ignited, a large (and noisy) pressure rise suddenly occurs in the combustion chamber (producing the
characteristic diesel knock), typically reaching around 600 psi levels, well above peak cylinder pressures in
spark-ignited gasoline engines (around 200 psi). The electronic fuel injection system is easily the most
expensive item going into a new CI engine. For comparison, gasoline electronic fuel injection systems are much
simpler and less expensive: pressures are only 4-5 bar (port injection) using solenoid injectors, and around 200
bar for direct injection (which is rising in popularity). Accordingly, a diesel engine will cost much more than a
gasoline engine of the same power level.
The result of such high diesel compression is that most of the internal moving parts and engine structures
everywhere must be “beefed up” to handle the high stress. For the same power output and/or displacement
levels, CI engines are much heavier than gasoline counterparts. Although that can render sluggish acceleration
on the highway, one upside is a much longer lasting engine. In the motor vehicle industry, the expectation for
engine overhaul intervals is around 150,000 miles for gasoline, 350,000 miles for light-medium duty diesels and

13. 500,000+ miles for HD diesels in trucks and buses. The longer life and enhanced reliability of CI engines
(compared to gasoline engines) is related to their overbuilt nature, lower operating speeds, lubricity of the fuel
oil, and lack of a spark-ignition system. The lower vapor pressure of diesel fuel accords additional safety
benefits, especially important in marine engine compartments.
Today, for emissions reasons, all new highway diesels in major industrialized countries use the 4-stroke cycle
(air intake, compression, power, exhaust expulsion).
For highway use, all CI engines today are turbocharged which, harnesses waste energy in the exhaust to
compress intake air. Unlike gasoline engines subject to detonation of the air-fuel mixture, CI engines have no
upper limit on intake manifold air pressure—up to failure of engine parts (like blowing a head gasket).
Turbocharger technology increases the specific power (hp or kw/liter of displacement) of CI engines by at least
50 percent..
6. Parts ofthe Diesel Engine and its function:
6.1 Cylinderblock:
A cylinder block is an integrated structure comprising the cylinder(s) of a reciprocating engine and often some
or all of their associated surrounding structures (coolant passages, intake and exhaust passages and ports, and
crankcase). The term engine block is often used synonymously with "cylinder block" .
In the basic terms of machine elements, the various main parts of an engine (such as cylinder(s), cylinder
head(s), coolant passages, intake and exhaust passages, and crankcase) are conceptually distinct, and these
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14. concepts can all be instantiated as discrete pieces that
are bolted
Figure 2 : CYLINDER BLOCK
6.2 Cylinder Head:
The cylinder head (often informally abbreviated to just head) sits above the cylinders on top of the cylinder
block. It closes in the top of the cylinder, forming the combustion chamber. This joint is sealed by a head
gasket. In most engines, the head also provides space for the passages that feed air and fuel to the cylinder, and
that allow the exhaust to escape. The head can also be a place to mount the valves, spark plugs, and fuel
injectors.
Figure 3: CYLINDER HEAD
6.3 Crankcase:
the crankcase is the housing for the crankshaft. The enclosure forms the largest cavity in the engine and is
located below the cylinder , which in a multicylinder engine are usually integrated into one or several cylinder
blocks. Crankcases have often been discrete parts, but more often they are integral with the cylinder bank,
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15. forming an engine block. Nevertheless, the area around the crankshaft is still usually called the crankcase.
Crankcases and other basic engine structural components (e.g., cylinders, cylinder blocks, cylinder heads, and
integrated combinations thereof) are typically made of cast iron or cast aluminium via sand casting.
6.4Piston,connectingrod,pistonringsand gudgeonpin:
Piston
A piston is a component of reciprocating engines. It is the moving component that is contained by a cylinder
and is made gas-tight by piston rings. In an engine, its purpose is to transfer force from expanding gas in the
cylinder to the crankshaft via a piston rod and/or connecting rod. In a pump, the function is reversed and force is
transferred from the crankshaft to the piston for the purpose of compressing or ejecting the fluid in the cylinder.
In some engines, the piston also acts as a valve by covering and uncovering ports in the cylinder wall.
Connecting rod
In a reciprocating piston engine, the connecting rod or conrod connects the piston to the crank or crankshaft.
Together with the crank, they form a simple mechanism that converts reciprocating motion into rotating motion.
Connecting rods may also convert rotating motion into reciprocating motion.
Gudgeon Pin
The gudgeon pin connects the piston to the connecting rod and provides a bearing for the connecting rod to
pivot upon as the piston moves.
Piston Ring
A piston ring is a split ring that fits into a groove on the outer diameter of a piston.
The three main functions of piston rings in reciprocating engines are :
1. Sealing the combustion chamber so that there is no transfer of gases from the combustion chamber to the
crank.
2. Supporting heat transfer from the piston to the cylinder wall.
3. Regulating engine oil consumption.
The gap in the piston ring compresses to a few thousandths of an inch when inside the cylinder bore.
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16. Figure 4: PISTON ASSEMBLY
6.5 Crankshaft:
The crankshaft, sometimes abbreviated to crank, is the part of an engine that
translates reciprocating linear piston motion into rotation. To convert the reciprocating motion into rotation,
the crankshaft has "crank throws" or "crankpins", additional bearing surfaces whose axis is offset from that of
the crank, to which the "big ends" of the connecting rods from each cylinder attach.
It is typically connected to a flywheel to reduce the pulsation characteristic of the four-stroke cycle, and
sometimes a torsional or vibrational damper at the opposite end, to reduce the torsional vibrations often caused
along the length of the crankshaft by the cylinders farthest from the output end acting on the torsional elasticity
of the metal.
Figure 5:CRANKSHAFT
6.6 Flywheel:
A flywheel is a rotating mechanical device that is used to store rotational energy. Flywheels have a significant
moment of inertia and thus resist changes in rotational speed. The amount of energy stored in a flywheel is
proportional to the square of its rotational speed. Energy is transferred to a flywheel by
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17. applying torque to it, thereby increasing its rotational speed, and hence its stored energy. Conversely, a flywheel
releases stored energy by applying torque to a mechanical load, thereby decreasing its rotational speed.
Three common uses of a flywheel include:
 They provide continuous energy when the energy source is discontinuous. For example, flywheels are used
in reciprocating engines because the energy source, torque from the engine, is intermittent.

 They deliver energy at rates beyond the ability of a continuous energy source. This is achieved by collecting
energy in the flywheel over time and then releasing the energy quickly, at rates that exceed the abilities of
the energy source.

 They control the orientation of a mechanical system. In such applications, the angular momentum of a
flywheel is purposely transferred to a load when energy is transferred to or from the flywheel.
Figure 6: FLYWHEEL
6.7 Liners:
1. Dry liners - Dry liner is made in the shape of barrel having a flange at the top which keeps it into position in
the cylinder block. The entire outer surface of the dry liner bears against the cylinder block casting and hence
has to be machined very accurately from the outside also. Thus it is not in direct contact with the cooling water
and hence is known as dry liner. Its thickness ranges from 1.5mm to 3mm. It is used mostly for reconditioning
warm cylinders.
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18. 2. Wet liners - A Wet liner forms a complete cylinder barrel. It is provided with a flange at the top which fits
into the groove in the cylinder block. At the bottom either the block or the liner is provided with grooves,
generally three in numbers, in which the packing rings made of rubber are inserted. The liner is in direct contact
with the cooling water and hence is known as wet liner. The outer surface of the liner does not require accurate
machining. Wet liners are thicker than dry liners, ranging from 1.5mm to 6mm
Figure 7:LINERS
6.8 Gaskets:
A gasket is a mechanical seal which fills the space between two or more mating surfaces, generally to prevent
leakage from or into the joined objects while under compression.
Gaskets allow "less-than-perfect" mating surfaces on machine parts where they can fill irregularities. Gaskets
are commonly produced by cutting from sheet materials.Gaskets for specific applications, such as high pressure
steam systems, may contain asbestos. However, due to health hazards associated with asbestos exposure.
6.9 Rockerarm:
The rocker arm is an oscillating lever that conveys radial movement from the cam lobe into linear movement at
the poppet valve to open it. One end is raised and lowered by a rotating lobe of the camshaft while the other end
acts on the valve stem. When the camshaft lobe raises the outside of the arm, the inside presses down on the
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19. valve stem, opening the valve. When the outside of the arm is permitted to return due to the camshafts rotation,
the inside rises, allowing the valve spring to close the valve.
The drive cam is driven by the camshaft. This pushes the rocker arm up and down about the trunnion pin or
rocker shaft. Friction may be reduced at the point of contact with the valve stem by a roller cam follower.
Figure 8: ROCKER ARM
6.10 Oil Pump:
The oil pump in an internal combustion engine circulates engine oil under pressure to the rotating bearings, the
sliding pistons and the camshaft of the engine. This lubricates the bearings, allows the use of higher-capacity
fluid bearings and also assists in cooling the engine.
As well as its primary purpose for lubrication, pressurized oil is increasingly used as a hydraulic fluid to power
small actuators. One of the first notable uses in this way was for hydraulic tappets in camshaft and valve
actuation. Increasingly common recent uses may include the tensioner for a timing beltor variators for variable
valve timing systems.
6.11 Exhaustmanifoldwithturbo charger:
A turbocharger, is a forced induction device used to allow more power to be produced by an engine of a given
size.A turbocharged engine can be more powerful and efficient than a naturally aspirated engine because the
turbine forces more air, and proportionately more fuel, into the combustion chamber than atmospheric pressure
alone.
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20. Figure 9: EXHAUST MANIFOLD WITH TURBOCHARGER
6.12 Water Pump :
A centrifugal pump is a rotodynamic pump that uses a rotating impeller to increase the pressure and flow rate of
a fluid. Centrifugal pumps are the most common type of pump used to move liquids through a piping system.
The fluid enters the pump impeller along or near to the rotating axis and is accelerated by the impeller, flowing
radially outward or axially into a diffuser or volute chamber, from where it exits into the downstream piping
system. Centrifugal pumps are typically used for large discharge through smaller heads.
Centrifugal pumps are most often associated with the radial-flow type. However, the term "centrifugal pump"
can be used to describe all impeller type rotodynamic pumps[4]
including the radial, axial and mixed-flow
variations.
6.13 Oil Filters:
An oil filter is a filter designed to remove contaminants from engine oil, transmission oil, lubricating oil, or
hydraulic oil.
6.14 Sump:
The bottom half of the crankcase is called the oil pan or sump. It is bolted or screwed to the lower flange of the
main casting of IC engine and usually is made of pressed steel or aluminium. Oil pan serves as the reservoir for
the storage,cooling and ventilation of engine lubricating oil.
The plane of the joint between the crankcase and the oil pan may be either on the level of the crankshaft axis or
it may be lower. If it is on the level of the crankshaft axis, it will increase the bottom oil pan portion. If it is
lower than this axis, it will increase upper portion of the crankcase thus increasing rigidity..
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21. 7. Dis-­­assembly ofdiesel engine :-­­
7.1 Engineremoval :-­­
1. Drain the cooling system by opening the drain cock.
2. Disconnect the battery at positive terminal to avoid possibility of short circuit.
3. Disconnect the fuel tank line by unscrewing the connecting nut.
4. Plug the fuel line to prevent leakage.
5. Remove the radiator stay bar.
6. Remove the radiator.
7. Remove the starting motor.
8. Disconnect the oil pressure and temperature sending unit wires at the units.
9. Disconnect the exhaust pipe at the exhaust manifold by removing the stud nuts.
10. Remove the two nuts and bolts from each engine support. Disconnect the engine ground strap. Remove
the Engine supports.
11. Remove two cylinder head bolts. Fit a suitable engine lifting bracket in place and re-tighten the cylinder
head bolts previously removed. Attach the engine lifting bracket to a lifting devices like mobile cranes
etc. Take up all slacks.
12. Separate the transmission section from the engine rear side.
13. Lift the Engine from the vehicle.
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22. 7.2 Enginedisassembly:-­­
For disassembling the engine it is mounted on a suitable engine repair stand. Priority to safety , principle
should be adapted to avoid accidents.
Now the engine is out of the vehicle in the workshop and the lube oil is drained by opening a drain nut .
1. Remove the water pump by unscrewing the bolts attached to the engine block.
2. Remove the exhaust manifold along with turbocharger.
3. Remove oil filter tube.
4. Remove thermostat.
5. Remove crankshaft pulley and vibration damper.
6. Remove intake manifold.
7. Remove cylinder head.
8. Remove timing gear cover.
9. Remove flywheel.
10. Remove flywheel housing.
11. Remove the fuel pump and all other pipe connections.
12. Remove camshaft.
13. Remove the sump by lifting the engine with a overhead crane.
14. Remove the oil pump (gear type) and its connections to the block .
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23. 15. Now invert the engine by min. 90 degrees so as to access to the crankshaft and con. Rod portion.
16. Unscrew the bolts of piston and connecting rods on crankshaft i.e. big-end bearing bolts and also main
bearing bolts so as to remove the crankshaft. Thus the crankshaft is lifted and removed and further sent
for inspection.
17. Now the piston is removed and inspected carefully to find any defects if there.
18. The liner which acts as the guide for piston and also cools the piston is removed by hammering process
and after removal is sent for inspection, mostly the linners are replaced.
After disassembling the engine the head sections turn out for inspecting the head of the engine, to check for any
leakages if there. Springs, Rocker arms, Push Rods, Levers are inspected to ensure the quality of repair work.
The block, the intake manifold, head, sump, flywheel housing, flywheel, timing gear housing etc. parts are sent
for cleaning, where high water pressure, air pressure and diesel is sprayed to ensure for clean parts. The diesel is
sprayed in the galleries for oil path inside the block or head and also inside the thread to remove all the
blockages if any. These blockages could lead the engine to seize if brought in operation without cleaning.
After the full inspection of the engine by the inspecting team the parts to be changed are enlisted and attached to
the Manager’s desk for approval. After the approval the parts of the supporting company are issued from the
store and the engine is again set on the workshop floor for assembling.
8. Testing
After the assembling the Engine is sent for testing where the engine is tested before being sent to the field work.
Engine noise, oil pressure, its temperature, power etc. are tested.
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25. Transmission:
Transmission is the act of passing something on in another place. A machine consists of a power source and a
power transmission system, which provides controlled application of the power. Merriam-Webster
defines transmission as an assembly of parts including the speed-changing gears and the propeller shaft by
which the power is transmitted from an engine to a live axle.[1]
Often transmission refers simply to
the gearbox that uses gears and gear trains to providespeed and torque conversions from a rotating power source
to another device. T he transmission generally is connected to the engine crankshaft via a flywheel and/or
clutch and/or fluid coupling. The output of the transmission is transmitted via driveshaft to one or more
differentials, which in turn, drive the wheels.
The workshop deals with the following series of automatic transmission:
1. CLBT-754
2. CLT-74
3. D15TR
4. D355
5. HD-78-2
6. D15 TC
An automatic transmission that selects an appropriate gear ratio without any operator intervention. They
primarily use hydraulics to select gears, depending on pressure exerted by fluid within the transmission
assembly. Rather than using a clutch to engage the transmission, a torque converter is placed in between the
engine and transmission. It is possible for the driver to control the number of gears in use or select reverse,
though precise control of which gear is in use may or may not be possible.
Automatic transmissions are easy to use. However, in the past, automatic transmissions of this type have had a
number of problems; they were complex and expensive, sometimes had reliability problems (which sometimes
caused more expenses in repair), have often been less fuel-efficient than their manual counterparts (due to
"slippage" in the torque converter), and their shift time was slower than a manual making them uncompetitive
for racing. With the advancement of modern automatic transmissions this has changed.
Attempts to improve fuel efficiency of automatic transmissions include the use of torque converters that lock up
beyond a certain speed or in higher gear ratios, eliminating power loss, and overdrive gears that automatically
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26. actuate above certain speeds. In older transmissions, both technologies could be intrusive, when conditions are
such that they repeatedly cut in and out as speed and such load factors as grade or wind vary slightly.
9. Purpose ofan automatic transmission:
Just like that of a manual transmission, the automatic transmission's primary job is to allow the engine to
operate in its narrow range of speeds while providing a wide range of output speeds.
Without a transmission, cars would be limited to one gear ratio, and that ratio would have to be selected to
allow the car to travel at the desired top speed. If you wanted a top speed of 80 mph, then the gear ratio would
be similar to third gear in most manual transmission cars.
You've probably never tried driving a manual transmission car using only third gear. If you did, you'd quickly
find out that you had almost no acceleration when starting out, and at high speeds, the engine would be
screaming along near the red-line. A car like this would wear out very quickly and would be nearly undriveable.
So the transmission uses gears to make more effective use of the engine's torque, and to keep the engine
operating at an appropriate speed. When towing or hauling heavy objects, your vehicle's transmission can get
hot enough to burn up the transmission fluid. In order to protect the transmission from serious damage, drivers
who tow should buy vehicles equipped with transmission coolers.
The key difference between a manual and an automatic transmission is that the manual transmission locks and
unlocks different sets of gears to the output shaft to achieve the various gear ratios, while in an automatic
transmission, the same set of gears produces all of the different gear ratios. The planetary gearset is the device
that makes this possible in an automatic transmission.
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27. 10. Howautomatic transmissionworks:
There are five major parts in a modern torque converter, they are from top to bottom:
1. impeller/cover assembly (also called a pump)
2. stator
3. turbine
4. torque converter clutch
5. Turbine
Imagine two fans side by side, and one of the fans blowing air into the other, this is how a torque
converter works, except it does this with an actual fluid in a contained housing. The air pushed off the blades of
one fan, will strike the blades of the fan next to it and spin it.
The impeller (first piece) is attached to the donut shape on the inside of the converter, and is driven by the
engine as it is welded to the inside of the converter, which is bolted to a drive plate or flexes plate.
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28. The turbine is the other set of blades opposite of the impeller, and is driven by the displaced oil from it. This
piece is splined to the transmission input shaft and is driven by the impeller, this operates similar to a manual
transmission clutch disc.
The stator resides in the very center of the torque converter. Its job is to redirect the fluid returning from the
turbine before it hits the pump again. This dramatically increases the efficiency of the torque converter.
The stator has a very aggressive blade design that almost completely reverses the direction of the fluid. A one-
way clutch (inside the stator) connects the stator to a fixed shaft in the transmission (the direction that the clutch
allows the stator to spin is noted in the figure above). Because of this arrangement, the stator cannot spin with
the fluid -- it can spin only in the opposite direction, forcing the fluid to change direction as it hits the stator
blades.
Something a little bit tricky happens when the car gets moving. There is a point, around 40 mph (64 kph), at
which both the pump and the turbine are spinning at almost the same speed (the pump always spins slightly
faster). At this point, the fluid returns from the turbine, entering the pump already moving in the same direction
as the pump, so the stator is not needed
The flex plate (or drive plate) flexes during torque multiplication, and is the result of the impeller pushing oil on
the turbine and the stator pushing the same oil back into the impeller, causing the two to repel sightly, and the
flex plate to flex in turn. It helps dampen the ride by allowing this movement to occur.
Now how does this all work?
The transmission oil pump is always driven by the engine, through an auxiliary shaft. Pump oil will fill the
torque converter up, and the fluid will be forced through the blades of the impeller due to centrifugal rotation of
the converter via engine rotation. This fluid force is curved by the impeller blades to strike the blades of the
turbine at a specific angle to provide sufficient power to turn the transmission.
Once the oil forces the turbine to turn, it has to go somewhere, and since the turbine is basically the opposite in
design, it flows back downward towards the center. Just opposite of the impeller, which brings oil in from the
center and throws it outward. If the turbine were allowed to exhaust its oil into the center uncontrolled, it would
create a huge turbulence inside, and create vibrations and lots of heat. This is where the stator comes in. Its job
is to redirect the fluid from the turbine, back into the impeller, which creates a pressure. This piece is only
functional when the impeller and turbine are not turning the same speed, as the speed difference is what causes
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29. the turbulence. When the shafts are turning close to the same as one another, the stator freewheels, as both
blades are turning similar enough for the turbine fluid to enter the impeller again, without the need to redirect it.
Figure 10:TORQUE CONVERTOR
There are two types of flow in a torque converter, vortex flow, and rotary flow.
Vortex Flow is the flow of fluid through the blades when the two blade speeds are different, like the engine is
turning 4500rpm (which is the speed of the impeller as well) and the transmission input shaft (turbine) is only
turning 3000rpm. This causes turbulence and is where the stator does its job by redirecting the fluid back to the
source, to multiply engine torque by creating pressure, which is acts like a gear reduction, only it happens
before power gets into the transmission.
Rotary Flow is achieved when the two blades are turning at a similar speed to one another. At this point the
stator's job is done, and is simply pushed along a one way clutch until a speed difference occurs again. Rotary
flow produces almost no torque multiplication because the engine and transmission are turning at near the same
speed, which would indicate cruising speeds or light throttle. The overall goal of the torque converter is to
achieve rotary flow, by using vortex flow to get there. Usually in each gear, there is about 500rpm difference
from when you let of the pedal, to full throttle. The RPM changes but the gear does not. This is the torque
converterattempting to make extra torque to get the turbine up to the engine's current speed faster.
Vortex flow achieves additional torque by reapplying the turbine exhaust oil back into the impeller, placing
pressure on it, and multiplying the apply force, resulting in additional torque.
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30. Rotary flow achieves a near 1:1 ratio, where speed is needed, and torque is not. Once the blades are of similar
speed, they can no longer produce torque since an object cannot turn faster with the same power applied to it
than the source that supplied it without physical gearing, and even if it could, it would be counter productive
since the impeller would lose its apply force, similar to starving an engine bearing of oil at high rpm.
What does a torque converter clutch do?
This is the mechanical link used when rotary flow is high, to provide a direct 1:1 ratio for the best possible fuel
mileage, without sacrificing acceleration and torque multiplication. Many people think their automatic is a 5
speed, but in fact it is a 4 speed, with a converter clutch, which will feel like a 5th gear shift when it locks.
Simply pressing the gas or the brake will disengage it, and the rpm will jump up/down around 200-400rpm
depending on the engine. Looking at the picture above, the TCC solenoid will apply oil pressure between the
turbine and the TCC face, pressing the clutch onto the machine surface in the apply housing. This locks the
turbine to the converter housing making it turn at engine speed. If you would like, you can think of it as slipping
4th gear in a manual transmission, and then dumping the clutch, preventing any further slippage.
Now on to the actual transmission. The case of the transmission serves to house all the internals. But on both
inside and outside, there are numerous devices that may not look so friendly, and allow the transmission to do
its job without your every intervention. The oil pan, side pan, servo covers ,shaft speed sensors, the PRNDL
(Gear Position) switch, cooler lines, and a lot more.
Oil Pump: This provides lubrication and hydraulic oil flow for the circuits in the valve body, apply oil for the
clutches and bands in the transmission, and oil for the torque converter. This particular pump is a variable
displacement vane type pump. It has the ability to change its output based on load, by using a pivoting housing
that can be controlled by a throttle valve, boost valve, or a solenoid valve if its electronically shifted. It is
always driven by the engine. Some use a gerotor type design, similar to a Honda oil pump.
Shaft Speed Sensors: Very similar to the speedometer sensor in design and function, these sensors are used to
determine if the incoming RPM and outgoing RPM are within a reasonable frame, to determine if the
transmission is operating normally. If a clutch slips, the sensors will detect this, and take appropriate action.
This can include placing the powertrain in limp-in mode to prevent damage, disabling the affected component if
it can, and producing a DTC to help diagnose the failure. Many of these codes are OEM dependent, due to the
proprietary design of the transmission, but there is a standard code set for automatic transmissions.
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31. Clutch Packs/Drums: These are used to drive members of a planetary gear set, and can be used in conjunction
with one way clutches to do this. The assembly consist of a drum, which is affixed to the one end of the object
to be driven, steel plates and clutches, and a piston in the back to force the clutches into the steel plates, this
engages a gear, or a planetary member, depending on design. The steel plates spline to the drum, and the
clutches spline to a shaft, or planetary member. If the outside of the drum is precision machined, a band may
also hold this member stationary for certain gears to make the assembly much smaller.
Accumulators: This is a cushion device, and is round in shape and usually 1-3 inches in size. It's job is to
cushion the apply of a gearshift by allowing hydraulic pressure to push downward on it, so the clutch applies
smoothly. It resists the oil apply pressure with spring pressure on the opposing side of the piston. The picture
above shows the stock spring, and the replacement metal rod to make the clutch apply faster, and harder. The
TV valve or a solenoid valve assembly can feed oil to the backside of this piston, opposing main line pressure,
to help engage the gear faster during high load acceleration.
Valve Body: This is the complex PCM of the transmission. A series of hydraulic circuits that allow hydraulic
oil to apply many different devices. In many cases they should not be serviced, only replaced as a unit.
Aftermarket kits that replace the spool valves and springs and other components such as accumulators to
enhance performance are available. These can turn the traditional economy transmission into a performance
machine.
Solenoids: These can be on/off or duty cycle solenoids that can both be either normally open, or normally
closed, depending on if the pressure is normally exhausted, or normally applied. They can apply clutches for
gears, along with other comfort pressures. The PCM or TCM, if equipped, uses engine sensors to determine the
drivers demand, by using throttle angle, manifold pressure, and rpm.
Planetary gearing
When we take apart and look inside an automatic transmission, you find a huge assortment of parts in a fairly
small space. Among other things, you see:
 An ingenious planetary gearset
 A set of bands to lock parts of a gearset
 A set of three wet-plate clutches to lock other parts of the gearset
 An incredibly odd hydraulic system that controls the clutches and bands
 A large gear pump to move transmission fluid around
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32. The center of attention is the planetary gearset. About the size of a cantaloupe, this one part creates all of the
different gear ratios that the transmission can produce. Everything else in the transmission is there to help
theplanetary gearset do its thing. This amazing piece of gearing has appeared on HowStuffWorks before. You
may recognize it from the electric screwdriver article. An automatic transmission contains two complete
planetary gearsets folded together into one component. See How Gear Ratios Work for an introduction to
planetary gearsets.
Any planetary gearset has three main components:
 The sungear
 The planet gears and the planet gears' carrier
 The ring gear
Each of these three components can be the input, the output or can be held stationary. Choosing which piece
plays which role determines the gear ratio for the gearset. Let's take a look at a single planetary gearset.
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33. Now that the gear portion is done, it will be time to explain how it actually shifts gears automatically. An
automatic comes in two types, Hydraulically controlled shift, or Electronically controlled shift. In either case,
they shift gears in the same manner, but use a different device to control the transmission. The following
diagram is for demonstration purposes only, and is greatly simplified to show how a valve body would function.
Refer to the picture below:
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34. 34 | P a g e

35. MACHINES & TOOLS USEDDURINGTHE TRAININGPERIOD:
1. TORQUE RENCH
2. SPANNERS
3. SOCKETS
4. SCREW-­­DRIVERS
5. HAMMER
6. COMPRESSOR
7. INJECTORCALIBRATION BENCH
8. DIAL GAGUE
9. COMPRESSOR
10. FILLET GAGUE
11. MICROMETER
12. VERNIERCALLIPER
13. CRANKHANDLE
14. T HANDLE
15. LUBRICANTS
16. LATHE MACHINE
17. MILLING MACHINE
18. GRINDINGMACHINE
19. AIRCOMPRESSOR
20. OVERHEAD CRANES
21. MOBILE CRANE
22. INDUCTION BEARINGHEATER
23. MEGGER
24. DROP TEST MACHINE
25. PULL MAC
26. WELDING MACHINE
27. TURNING MACHINE
28. VOLTMETER
29. AMMETER
30. GALVANOMETER
31. TACHOMETER
32. POLARITYTEST METER
33. PHASECHECKING MACHINE
34. VALVECHECKINGMACHINE
35. AUTOMATED TRANSMISSION TEST BENCH
36. MOISTURE CONTOLINGHEATINGCHAMBER
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