98313323 final training report turbocharger

2012

SUBMITTED BY:-

OSCAR ARUN LOUIS

B.Tech. ME

LOCO SHED TRAINING REPORT

ACKNOWLEDGEMENT

I take this opportunity to express my sincere gratitude to all the people

who have been associated in the successful completion of industrial

training and this project. I would like to show my greatest appreciation to

the highly esteemed and devoted technical staff, supervisors of the Diesel

Loco Shed, Agra. I m highly indebted to them for their tremendous

support and help during the completion of our training and project.

I m grateful to the D.M.E, Loco Shed and training co-ordinator Mr.

Pratap for admitting me in the shed for my industrial training. I would like

to thank to all those peoples who directly or indirectly helped and guided

me to complete my training and project in the shed.

I would also like to express my heartfelt gratitude to the Dean of

―Shepherd School of Engineering and Technology‖ and Head of the

Department of ―Mechanical Engineering and Applied Mechanics” for

providing me an opportunity to go for the industrial training.

Finally, I may say that I do not claim absolute perfection . However, I have

strived hard to gain knowledge during the training and present a good

project report.

OSCAR LOUIS

B.Tech ME (VIIth

)

S.H.I.A.T.S

INDIAN RAILWAY

HISTORY

Indian Railways is the state-owned railway company of India. It comes under

the Ministry of Railways. Indian Railways has one of the largest and busiest rail

networks in the world, transporting over 18 million passengers and more than 2

million tonnes of freight daily. Its revenue is Rs.107.66 billion. It is the world's

largest commercial employer, with more than 1.4 million employees. It operates

rail transport on 6,909 stations over a total route length of more than

63,327 kilometers(39,350 miles).The fleet of Indian railway includes over

200,000 (freight) wagons, 50,000 coaches and 8,000 locomotives. It also owns

locomotive and coach production facilities. It was founded in 1853 under the

East India Company.

Indian Railways is administered by the Railway Board. Indian Railways is

divided into 16 zones. Each zone railway is made up of a certain number of

divisions. There are a total of sixty-seven divisions. It also operates the Kolkata

metro. There are six manufacturing plants of the Indian Railways. The total

length of track used by Indian Railways is about 108,805 km (67,608 mi) while

the total route length of the network is 63,465 km (39,435 mi). About 40% of

the total track kilometer is electrified & almost all electrified sections use

25,000 V AC. Indian railways uses four rail track gauges:-

1. The broad gauge (1670 mm)

2. The meter gauge (1000 mm)

3. Narrow gauge (762 mm)

4. Narrow gauge (610 mm).

Indian Railways operates about 9,000 passenger trains and transports 18

million passengers daily .Indian Railways makes 70% of its revenues and most

of its profits from the freight sector, and uses these profits to cross-subsidies the

loss-making passenger sector. The Rajdhani Express and Shatabdi Express are

the fastest trains of India

CLASSIFICATION

1. Standard ―Gauge‖ designations and dimensions:-

W = Broad gauge (1.67 m)

Y = Medium gauge ( 1 m)

Z = Narrow gauge ( 0.762 m)

N = Narrow gauge ( 0.610 m)

2. ― Type of Traction‖ designations:-

D = Diesel-electric traction

C = DC traction

A = AC traction

CA=Dual power AC/DC traction

3. The ― type of load‖ or ―Service‖ designations:-

M= Mixed service

P = Passenger

G= Goods

S = Shunting

4. ― Horse power ‖ designations from June 2002 (except WDP-1 & WDM-2

LOCOS)

‗ 3 ‘ For 3000 horsepower



‗ A ‘ For extra 100 horsepower

‗B‘ For extra 200 horsepower and so on.

Hence ‗WDM-3A‘ indicates a broad gauge loco with diesel-electric traction. It

is for mixed services and has 3100 horsepower.

DIESEL SHED AGRA

INTRODUCTION

Diesel locomotive shed is an industrial-technical setup, where repair and

maintenance works of diesel locomotives is carried out, so as to keep the loco

working properly. It contributes to increase the operational life of diesel

locomotives and tries to minimize the line failures. The technical manpower of

a shed also increases the efficiency of the loco and remedies the failures of loco.

The shed consists of the infrastructure to berth, dismantle, repair and test the

loco and subsystems. The shed working is heavily based on the manual methods

of doing the maintenance job and very less automation processes are used in

sheds, especially in India.

The diesel shed usually has:-

Berths and platforms for loco maintenance.

Pits for under frame maintenance

Heavy lift cranes and lifting jacks

Fuel storage and lube oil storage, water treatment plant and testing

labs etc.

Sub-assembly overhauling and repairing sections

ABOUT DIESEL SHED AGC

Diesel Shed, Agra started functioning in 1986. The shed is headed by DME (D)

was AGC. It is located at km. 1334/5 about 1.25 Km away from AGC station

towards Delhi end. A captive store headed by AMM (D) is attached to the shed.

At present the shed holds WDS4 and WDM2 both with Dual Break System,

especially for the shunting purpose. The shed cater the needs of Northern

Central Railway.

No doubt the reliability, safety through preventive and predictive maintenance

is high priority of the shed. To meet out the quality standard shed has taken

various steps and obtaining of the ISO-9001-200O& ISO 14001 OHSAS

CERTIFICATION is among of them. The Diesel Shed is equipped with modern

machines and plant required for Maintenance of Diesel Locomotives and has an

attached store depot. The morale of supervisors and staff of the shed is very

high and whole shed works like a well-knit team.

Introduction to WDM-2

WDM-2s are 2600 hp Alco models (RSD29 / DL560C). Co-Co, 16-cylinder,

4-stroke turbo-supercharged engine. Introduced in 1962. The first units were

imported fully built from Alco. After DLW was set up, 12 of these were

produced from kits imported from Alco (order no. D3389). After 1964, DLW

produced this loco in vast numbers in lots of different configurations. This loco

model was IR's workhorse for the second half of the 20th century, and perhaps

the one loco that has an iconic association with IR for many people. These locos

are found all over India hauling goods and passenger trains — the standard

workhorse of IR. Many crack trains of IR used to be double-headed by WDM-2

locos; this has decreased now owing to the electrification of most important

sections and the use of more powerful locos. A single WDM-2 can generally

haul around 9 passenger coaches; twin WDM-2's were therefore used for 18-

coach trains.

Jumbos – A few locos of the WDM-2 class

produced in 1978-79 have a full-width short hood;

these are unofficially termed 'Jumbos' by the crew.

These range from serial numbers around 17796 or

so to about 17895 or so (17899 and above are

known to be 'normal' WDM-2s). These were

apparently produced with the idea of improving the

visibility for the drivers, but it was learned later that it did not make much of a

difference under the typical operating conditions of these locos. Some of these

were later modified to have narrower short hoods to look more like the other

WDM-2's. Two locos, #17881 and #17882, were trial locos produced by DLW

when they were considering shutting down Jumbo production; these look like

ordinary WDM-2 locos, even though there are other Jumbos with higher road

numbers than them. Some Jumbos have undergone further modifications: Loco

#17854 was a Jumbo based at Jhansi in 1981; now [6/04] it has been rebuilt as a

WDM-3A locomotive (based at Pune) by DCW,

Patiala.

The classification WDM-2A is applied to those

that were re-fitted with air brakes (most of these

therefore have dual braking capability), while

WDM-2B is applied to more recent locos built

with air brakes as the original equipment (these

very rarely have vacuum braking capability in

addition, especially if they have been rebuilt by Golden Rock). (However, in the

past, before the widespread use of air-brakes, a few modified versions with a

low short hood at one end like the WDS-6 were also classified WDM-2A.) A

few WDM-2 locos of the Erode shed have been modified and sport a full-

forward cab at one end, with the dynamic brake grid, blower, etc. moved

between the cab and the traction alternator.

The original Alco designs had a 10-day, 3000km maintenance schedule, which

was later extended by some modifications to a 14-day schedule. Now [1/02], the

schedule is being extended to 30 days by increasing the capacities for various

fluids (lubrication oil, etc.), and improving some bearings (mainly, using roller

bearings for the suspension). The original WDM-2 bearings were very

susceptible to failure. However, given the age of this model, unsurprisingly

even locos that have been modified for a 14-day schedule do often require more

frequent maintenance or minor repair so they end up being put on a 7-day

schedule anyway.

WDM-2 locos are excepted from the new mainline diesel classification scheme

and will remain classified as WDM-2 and not 'WDM-2F' as they might be in the

new scheme based on their horsepower.

The first one supplied by Alco was #18040. This one is no longer in use and is

now preserved at the National Railway Museum at New Delhi. The second one

from Alco, #18041, is currently [7/05] homed at Kalyan shed and is often seen

hauling the Diva - Vasai DMU service. The first WDM-2 built by DLW,

#18233, is now at Andal shed (not much in use). The last WDM-2's were in the

16000 series. The very last one is #16887.

The WDM-2 locos have a max. speed of 120km/h. There are generally speaking

no restrictions for running with the long hood leading, although it's been

reported that in some cases the practice was to limit it to 100km/h. The gear

ratio is 65:18.

Some WDM-2 units are being converted [2/02] to have AC-DC transmission

(alternator driving DC traction motors) by DCW, Patiala. Golden Rock

workshops have also been renovating some WDM-2 locos with new features

such as twin-beam headlamps.

Only one WDM-2 loco (#16859, Ernakulam shed) is known to have had cab air-

conditioning fitted. This was the first loco to have air-conditioning in India; this

was done by the ERS shed in 1997 right after receiving the loco from DLW, but

it was disabled later as the auxiliary alternator proved too weak to run the air-

conditioner well.

A few WDM-2 locos downgraded for shunting duties have been seen marked

with a WDM-2S class name; e.g., some at Itwari shed [2003] and some at

Kurla. A few have also been spotted bearing the class name WDS-2, e.g., those

at the Kalyan shed where they are used for shunting. These appear to be quirks

of the local shed staff and not officially recognized classifications.

DCW Patiala has rebuilt some WDM-2 units to class WDM-3A/WDM-2C

specifications. These are a little different from

the normal WDM-2C from DLW. They look

very similar to WDM-2's, except for a bulge on

one of the doors of the hood; this is due to the

presence of a centrifugal fuel filter which

moved there because the model required larger

aftercoolers. There are some other slight

differences in appearance. These units have a GE turbocharger and a different

expressor with integral air drying facility. They have a Woodwards governor

which leads to even running and idling, and (to the great disappintment of Alco

smoke fans) reduces the amount of black smoke during intense acceleration.

These also have roller bearings for the suspension, improving on the

longstanding problem of bearing failures on the regular WDM-2 model.

TURBO SUPERCHARGER

INTRODUCTION

The diesel engine produces mechanical energy by converting heat energy

derived from burning of fuel inside the cylinder. For efficient burning of fuel,

availability of sufficient air in proper ratio is a prerequisite.

In a naturally aspirated engine, during the suction stroke, air is being sucked

into the cylinder from the atmosphere. The volume of air thus drawn into the

cylinder through restricted inlet valve passage, within a limited time would also

be limited and at a pressure slightly less than the atmosphere. The availability of

less quantity of air of low density inside the cylinder would limit the scope of

burning of fuel. Hence mechanical power produced in the cylinder is also

limited.

An improvement in the naturally aspirated engines is the super-charged or

pressure charged engines. During the suction stroke, pressurised stroke of high

density is being charged into the cylinder through the open suction valve. Air of

higher density containing more oxygen will make it possible to inject more fuel

into the same size of cylinders and produce more power, by effectively burning

it.

TURBOSUPERCHARGERS

A turbosupercharger, or turbo, is a gas compressor that is used for forced-

induction of an internal combustion engine. It increases the density of air

entering the engine to create more power.

A turbosupercharger has the compressor powered by a turbine, driven by the

engine's own exhaust gases. The turbine and compressor are mounted on a

shared shaft. The turbine converts exhaust heat and pressure to rotational force,

which is in turn used to drive the compressor. The compressor draws in ambient

air and pumps it in to the intake manifold at increased pressure, resulting in a

greater mass of air entering the cylinders on each intake stroke.

Turbosupercharging dramatically improves the engine's specific power, power-

to-weight ratio and performance characteristics which are normally poor in non-

turbosupercharged diesel engines.

TURBOS USED IN DIESEL LOCOMOTIVE

In diesel locomotives, different turbos are used for different engines on the basis

of their horsepower and make. Still, their general function remains the same i.e.

to provide compressed air to the engine by employing the energy of exhaust

gases. The exhaust manifold is connected to the inlet of the turbocharger. The

exhaust gases enter the gas inlet casing where they are directed towards the

nozzle ring. The function of the nozzle ring is to guide the exhaust gases and

reduce shock on the turbine blades. The exhaust gases impinge on the turbine

blades and cause the turbine to rotate on their way out to the atmosphere

through the chimney.

The rotating turbine causes the impeller of the compressor to rotate along with it

since they are mounted on the same shaft. The compressor starts sucking air

through the air inlet casing and compresses it due to the centrifugal action of the

impeller. After leaving the impeller, the air gets compressed further in the

diffuser vanes. From here the compressed air is passed into the blower casing,

which guides the air to an after cooler.

The function of the after cooler is to cool the compressed air and consequently

reduce its specific volume. The pressure of this compressed air is in the range of

1.2-1.8 kg/cm2, and this is known as BOOSTER AIR PRESSURE (BAP). This

compressed air is then introduced into the air gallery, which is connected to the

intake valves of all the cylinders.

ALCO FRONT VIEW

ALCO TOP VIEW

ALCO ASSEMBLY

GE (DOUBLE DISCHARGE) FRONT VIEW

GE (DOUBLE DISCHARGE) TOP VIEW

GE (DOUBLE DISCHARGE) BOTTOM VIEW

GE (DOUBLE DISCHARGE) ASSEMBLY

TURBO OPERATING DIFFICULTIES:

Operating difficulties can be prevented providing the daily turbocharger

operating data is measured and regular maintenance and inspection routines are

adhered to.

To assist in identifying causes of performance deterioration, the following table

has been formed:

OPERATING

DIFFICULTIES

PROBABLE CAUSE REMEDIAL

MEASURES

Engine starts running but the

turbocharger does not. Foreign matter/debris caught

between the turbine blade tips

and the shroud ring.

Blade tips rubbing the shroud

ring.

Bearing Disorder

Provide cleaning and eliminate

the cause for the ingress of the

foreign matter.

Inspect and replace with new

bearing.

Turbocharger experiences

surging during operating. Fouling of turbine nozzle,

blades.

Engine Cylinder unbalance.

Note: Rapid Changes of the

engine load, particularly during

shut-down can cause

turbocharger surging.

Cleaning of the turbine side of

turbocharger as required.

Refer to Engine Builders

Instruction Manual.

Exhaust gas temperature higher

than normal.

Fouling or damage to turbine

nozzle or turbine blades.

Lack of air e.g.: dirty air filter.

Exhaust back pressure too high.

Charge air cooler dirty, cooling

Cleaning the turbine side of the

turbocharger or component

replacement.

Clean as required.

Investigate cause.

Clean and adjust as Makers

water temperature too high.

Engine fault in fuel injection

system.

Instruction Manual.

Charge air (boost) pressure

lower than normal.

Pressure gauge faulty or

connection to it is leaking.

Gas leakage at engine exhaust

manifold.

Dirty Air filter, causing

pressure drop.

Dirty turbocharger.

Turbine blades or nozzle ring

damage.

Rectify.

See Engine Builders Instruction

Manual.

Clean air as required.

Cleaning of complete

turbocharger required.

Inspect and replace as

necessary.

Charge air pressure (boost)

higher than normal.

Pressure gauge reading

incorrectly.

Nozzle ring clogged with

carbon deposits.

Engine Overload, engine output

higher than expected.

Fault in engine fuel injection

system.

Rectify.

Clean as required.

Consult Engine Builders

Instruction Manual.

Consult Engine Builders

Instruction Manual.

Turbocharger Vibration Severe unbalance of rotor due

to dirt or damaged turbine

blades.

Bent rotor shaft.

Defective bearings.

Rebalance the rotor assembly.


necessary.


necessary.

TURBO OVERHAULING

The overhauling and servicing of a turbosupercharger is broadly

divided into five parts which are:

Dismantling of the turbo

Cleaning of the turbo

Inspection of different parts

Repair and rotor balancing

Assembly of the turbo

DISMANTLING OF THE TURBO

Dismantling of a turbo requires trained personnel and special tools (allen keys,

spanners, suspension yoke, support, etc). It is a complicated process and should

be done very carefully after referring to the manufacturer‘s instruction manual.

CLEANING OF THE TURBO

Cleaning work includes regular visual checks and the cleaning of parts to ensure

the correct functioning of the turbo.

Outline of cleaning work

The following figure explains the various symbols used in the previous

figure:

GAS CASING:

Deposits often form on the nozzle ring and the turbine blades. Impaired

efficiency and performance of the engine are the result.

Thick and irregular deposits can also result in an un-permissible unbalance of

the rotor.

Cleaning of the cooling water passage of gas outlet casing:

Commercial HCL of 5% concentration is used for cleaning and defurring. An

inhibitor is added to reduce the corrosion of cast iron.

Neutralisation with 5% NaOH (alkaline) solution follows the acid wash.

Fresh water is used foe flushing/rinsing.

All casing gaskets are replaced.

Gas inlet casing:

Deposits are cleaned with soft wire brush and with either diesel/kerosene + 20%

mineral oil solution (80/20 solution).

BEARING CASING:

Cleaning of the sealing air ducts:

The carbon deposits are dissolved and cleaning is done with the help of flexible

wire for ensuring free passage.

Compressed air is used to check that the sealing air ducts in the bearing casing

are unobstructed / unchoked.

Oil Passages:

It is cleaned with 80% kerosene/diesel + 20% mineral oil solution (i.e. 80/20

solution).

AIR OUTLET CASING:

The deposits are cleaned with soft wire brush and 80/20 solution.

ROTOR PARTS:

The turbine blades can be cleaned by glass bead blasting. The seating areas for

compressor wheel set, thrust bearing and floating bushes (Bearing compressor

side + Turbine side) are protected by means of rubber sleeve. The cleaning of

the compressor wheel set is carried out with 80/20 solution and therefore with

malmal (piece of cloth).

Rotating parts are thoroughly cleaned uniformly as uneven residual deposits

lead to unbalance.

BEARING PARTS:

All bearing parts, bearing covers are cleaned in 80/20 solution and with malmal

(piece of cloth). Special care is taken to clean the carbon deposits from the ―O‖

ring grooves and the oil supply/oil drain lines.

INSPECTION OF THE TURBO:

After dismantling and cleaning of the turbo, it is inspected for any faults. All the

clearances and blade conditions are checked and a note of all the repair work

needed is made.

REPAIR AND BALANCING OF ROTOR:

Various parts of the turbo are repaired as necessary. The rotor is examined

carefully and any distorted turbine blade is ground with a grinder so that it is

smooth again. The rotor is then checked if it is unbalanced and is balanced on a

Rotor Balancing Machine if needed.

In the course of manufacture, following parts are balanced individually:

Shaft

Sets of compressor wheel

While the engine is running, many reasons may cause unbalance to the

rotor:

Mechanical damages on the rotor, i.e. foreign bodies.

Uneven deposits of layer of dirt/carbon.

Abrasion on the compressor or the turbine caused by hard particles in the

intake air or in the exhaust gas.

Balancing must be done when:

Rotating components feature mechanical damages.

After reblading of turbine.

After repairs on the inducer or compressor wheel.

After replacing the inducer or compressor wheel.

Balancing is not required when:

A new bladed shaft is assembled into the turbocharger.

If, due to a change of specification, the set of wheels has to be changed

for a new one.

ABRO ROTOR BALNCING MACHINE

GE ROTOR ON BALANCING MACHINE

TURBO RUNDOWN TIME

The Turbo Rundown Time (TRD) of a turbo is the total time taken by the

turbo to come to a standstill, measured from the instant the crankshaft of the

engine stops. This time should be within a certain limit prescribed by the

manufacturer. If not so, it indicates a fault in the turbo. The rundown times of

different turbos have been mentioned earlier.

Turbo Rundown Test (for WDM-2 Loco)

This test is to be conducted if the Booster (Turbocharger in WDM-2 pidgin) is

not developing proper pressure during a run.

1. Secure the loco: Keep the A9 (Train Brake lever) in released condition;

keep the SA9 (Loco brake lever) in an applied condition; switch off the

GF (Generator Field); keep the reverser in neutral condition; and put the

ECS (Engine control switch) in the run mode.

2. The driver should climb on top of the hood and sight the turbine of the

turbocharger through the chimney.

3. The assistant should raise the engine to 4th notch rpm and allow the

engine to stabilize in speed.

4. As the engine begins to stop turning, the assistant must quickly get down

and come to the hood door to the Expressor.

5. He must give a signal to the driver as to the instant the huge engine stops

rotating by looking at the crankshaft of the engine coupled to the

expressor.

6. The driver must count the number of seconds the exhaust turbine takes to

come to a stop, from the instant the engine has come to a standstill.

7. If the turbine (which revolves at 18,000 to 19,000 rpm) takes more than

90 seconds then it is a good turbocharger, any reduction in the period of

spinning down is an indication of a faulty turbo.

TURBO SUPERCHARGER AND ITS WORKING PRINCIPLE

The exhaust gas discharge from all the cylinders accumulate in the common

exhaust manifold at the end of which, turbosupercharger is fitted. The gas

under pressure there after enters the turbosupercharger through the torpedo

shaped bell mouth connector and then passes through the fixed nozzle ring.

Then it is directed on the turbine blades at increased pressure and at the most

suitable angle to achieve rotary motion of the turbine at maximum efficiency.

After rotating the turbine, the exhaust gas goes out to the atmosphere through

the exhaust chimney. The turbine has a centrifugal blower mounted at the other

end of the same shaft and the rotation of the turbine drives the blower at the

same speed. The blower connected to the atmosphere through a set of oil bath

filters, sucks air from atmosphere, and delivers at higher velocity. The air then

passes through the diffuser inside the turbosupercharger, where the velocity is

diffused to increase the pressure of air before it is delivered from the turbo-

supercharger.

Pressurising air increases its density, but due to compression heat develops. It

causes expansion and reduces the density. This effects supply of high-density

air to the engine. To take care of this, air is passed through a heat exchanger

known as after cooler. The after cooler is a radiator, where cooling water of

lower temperature is circulated through the tubes and around the tubes air

passes. The heat in the air is thus transferred to the cooling water and air regains

its lost density. From the after cooler air goes to a common inlet manifold

connected to each cylinder head. In the suction stroke as soon as the inlet valve

opens the booster air of higher pressure density rushes into the cylinder

completing the process of super charging.

The engine initially starts as naturally aspirated engine. With the increased

quantity of fuel injection increases the exhaust gas pressure on the turbine. Thus

the self-adjusting system maintains a proper air and fuel ratio under all speed

and load conditions of the engine on its own. The maximum rotational speed of

the turbine is 18000/22000 rpm for the Turbo supercharger and creates max. Of

1.8 kg/cm2 air pressure in air manifold of diesel engine, known as Booster Air

Pressure (BAP). Low booster pressure causes black smoke due to incomplete

combustion of fuel. High exhaust gas temperature due to after burning of fuel

may result in considerable damage to the turbo supercharger and other

component in the engine.

MAIN COMPONENTS OF TURBO-SUPERCHARGER

Turbo- supercharger consists of following main components.

Gas inlet casing.

Turbine casing.

Intermediate casing

Blower casing with diffuser

Rotor assembly with turbine and rotor on the same shaft.

ROTOR ASSEMBLY

The rotor assembly consists of rotor shaft, rotor blades, thrust collar,

impeller, inducer, centre studs, nosepiece, locknut etc. assembled together. The

rotor blades are fitted into fir tree slots, and locked by tab lock washers. This is

a dynamically balanced component, as this has a very high rotational speed.

LUBRICATING, COOLING AND AIR CUSHIONING

LUBRICATING SYSTEM

One branch line from the lubricating system of the engine is connected to

the turbosupercharger. Oil from the lube oils system circulated through the

turbosupercharger for lubrication of its bearings. After the lubrication is over,

the oil returns back to the lube oil system through a return pipe. Oil seals are

provided on both the turbine and blower ends of the bearings to prevent oil

leakage to the blower or the turbine housing.

COOLING SYSTEM

The cooling system is integral to the water cooling system of the engine.

Circulation of water takes place through the intermediate casing and the turbine

casing, which are in contact with hot exhaust gases. The cooling water after

being circulated through the turbosupercharger returns back again to the

cooling system of the locomotive.

AIR CUSHIONING

There is an arrangement for air cushioning between the rotor disc and the

intermediate casing face to reduce thrust load on the thrust face of the bearing

which also solve the following purposes.

It prevents hot gases from coming in contact with the lube oil.

It prevents leakage of lube oil through oil seals.

It cools the hot turbine disc.

Pressurised air from the blower casing is taken through a pipe inserted in the

turbosupercharger to the space between the rotor disc and the intermediate

casing. It serves the purpose as described above.

AFTER COOLER

It is a simple radiator, which cools the air to increase its density. Scales

formation on the tubes, both internally and externally, or choking of the tubes

can reduce heat transfer capacity. This can also reduce the flow of air through it.

This reduces the efficiency of the diesel engine. This is evident from black

exhaust smoke emissions and a fall in booster pressure.

Fitments of higher capacity Turbo Supercharger- following new

generation Turbo Superchargers have been identified by diesel shed TKD for

2600/3100HP diesel engine and tabulated in table 1.

TABLE 1

TYPE POWER COOLING

1.ALCO 2600HP Water cooled

2.ABB TPL61 3100HP Air cooled

3.HISPANO SUIZA HS 5800 NG 3100HP Air cooled

4. GE 7S1716 3100HP Water cooled

5. NAPIER NA-295 2300,2600&3100HP Water cooled

6. ABB VTC 304 2300,2600&3100HP Water cooled

TURBO RUN –DOWN TEST

Turbo run-down test is a very common type of test done to check the free

running time of turbo rotor. It indicates whether there is any abnormal sound in

the turbo, seizer/ partial seizer of bearing, physical damages to the turbine, or

any other abnormality inside it. The engine is started and warmed up to normal

working conditions and running at fourth notch speed. Engine is then shut down

through the over speed trip mechanism. When the rotation of the crank shaft

stops, the free running time of the turbine is watched through the chimney and

recorded by a stop watch. The time limit for free running is 90 to 180 seconds.

Low or high turbo run down time are both considered to be harmful for the

engine.

ROTOR BALANCING MACHINE

A balancing machine is a measuring tool used for balancing rotating

machine parts such as rotors of turbo subercharger,electric motors,fans, turbines

etc. The machine usually consists of two rigid pedestals, with suspension and

bearings on top.The unit under test is placed on the bearings and is rotated with

a belt. As the part is rotated, the vibration in the suspension is detected with

sensors and that information is used to determine the amount of unbalance in

the part. Along with phase information, the machine can determine how much

and where to add or remove weights to balance the part.

ADVANTAGES OF SUPER CHARGED ENGINES

A super charged engine can produce 50 percent or more power than a

naturally aspirated engine. The power to weight ratio in such a case is

much more favorable.

Better scavenging in the cylinders. This ensures carbon free cylinders

and valves, and better health for the engine also.

Better ignition due to higher temperature developed by higher

compression in the cylinder.

It increases breathing capacity of engine

Better fuel efficiency due to complete combustion of fuel .

Defect in Turbochargers

Low Booster Air Pressure (BAP).

Oil throwing from Turbocharger because of seal damage or out of

clearance.

Surging- Back Pressure due to uneven gap in Nozzle Ring or Diffuser

Ring.

Must change components of Turbocharger.

Intermediate casing gasket.

Water outlet pipe flange gasket.

Water inlet pipe flange gasket.

Lube Oil inlet pipe rubber ‗o‘ ring.

Turbine end Bearing.

Blower end Bearing.

Chimney gasket.

Rubber ‗o‘ Ring kit.

Spring Washers.

Lock Washer Rotor Stud.

98313323 final training report turbocharger

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