1687549.docx

A

ACKNOWLEDGEMENT We owe a great many thanks to a great many people who helped and supported us throughout the project and led it to a successful completion. We record our respect and gratitude to supervisor Mr.RAJ KIRAN Asst. Professor, department of mechanical engineering for his valuable guidance and constant encouragement in carrying out the project work. We thankful to coordinator Mr. K. KISHORE KUMAR, Assistant Professor, Department of Mechanical Engineering for his valuable guidance in carrying out the project. We take this opportunity to thank Dr. V. PRABHAKARA RAO, Professor and head of the department Mechanical Engineering for his encouragement he has given us throughout the project. We extremely grateful to Professor Dr. D.V.RAVI SHANKAR Principal of TKRCET. Who has been a constant source of inspiration, motivation and support.

We should like to extend our sincere thanks to our project guide Smt. K.SWETHA, Junior Engineer, Diesel Loco Shed, Kazipet.

A.BHAGAWAN

15K91A0309

B.KISHORE

15K91A0319

D.NAVEEN

15K91A0332

G.SRIKANTH

15K91A0339

G.SHRAVAN KUMAR

15K91A0344

ABSTRACT

Turbo supercharger act as lungs in a CI engine. They enhance the performance of a CI engine by pushing in more air into cylinder which leads to complete burning of fuel thus delivering more power to weight ratio. This work deals with performance of the turbo supercharger used in locomotives. This includes the role played the by the turbo superchargers in increasing the mean effective pressure which in turn leads to greater power to weight ratio being developed by the engine. This on the other hand leads to an effect of increasing the peak temperature of the inlet air into the cylinders. The DIESEL LOCO SHED, KAZIPET is providing us all the practical references and guidance.

CONTENTS PAGE NO. CHAPTER-1 INTRODUCTION

1

CHAPTER-2 LITERATURE AND SURVEY

2

CHAPTER-3 WORKING PRINCIPLE 3.1.Main components

7 9

3.1.1.Turbine

10

3.1.2.Compressor

11

3.1.3.Center hosing

12

3.2.Types of super chargers

13

3.3.Difference between turbo charger and super charger

14

3.4.Overhauling procedure

15

3.5.Preliminaries before dismantling

17

3.6.Turbocharger dismantling procedure

19

3.6.1.Compressor side removal 3.6.2.Turbine side removal 3.7.Types of cleaning

22 24

3.7.1.Dry cleaning 3.7.2.Wet cleaning 3.8.Inspection

25

3.8.1.Pre-cleaning 3.8.2.Application of penetrate

26

3.8.3.Excess penetrant removal 3.8.4.Application of developer 3.8.5.Inspection

37

CHAPTER-4 DYNAMIC BALANCE

28

4.1.Assembly

30

CHAPTER-5 ADVANTAGES AND DISADVANTAGES OF TURBO SUPERCHARGER 5.1.Advantages

33

5.2.Disadvantages

34

CHAPTER-6 TROUBLES AND TROUBLE SHOOTING

35

CHAPTER-7 CONCLUSION

38

REFERENCE

39

LIST OF FIGURES FIGURE NUMBER

FIGURE NAME

PAGE NO.

3.1

Turbocharger

7

3.1.1

Turbine

10

3.1.2

Compressor

11

3.1.3

Centre housing

12

3.4.1

Super turbo charger

16

3.5.1

Turbine

17

3.6.1.

Compressor wheel before overhauling

20

3.6.1(a)

Compressor wheel after overhauling

20

3.6.1(b)

Turbine blade before overhauling

21

3.6.1(c)

Turbine blade after overhauling

21

3.7.1

Dry cleaning of turbo charger

24

4.1

Dynamic balance of super charger

28

4.1(a)

Resultant couple force

28

4.1.2

Turbine casing

30

4.1.3

Bearing housing

30

CHAPTER-1 INTRODUCTION

A turbocharger, or turbo (colloquialism), from Greek "τύρβη" ("wake"), (also from Latin "turbo" ("spinning top"),) is a turbine-driven forced induction device that increases an engine's efficiency and power by forcing extra air into the combustion chamber. This improvement over a naturally aspiratedengine's output results because the turbine can force more air, and proportionately more fuel, into the combustion chamber than atmospheric pressure alone.

Turbochargers were originally known as turbosuperchargers when all forced inductiondevices were classified as superchargers. Nowadays the term "supercharger" is usually applied to only mechanically driven forced induction devices. The key difference between a turbocharger and a conventional supercharger is that the latter is mechanically driven by the engine, often through a belt connected to the crankshaft, whereas a turbocharger is powered by a turbine driven by the engine's exhaust gas. Compared to a mechanically driven supercharger, turbochargers tend to be more efficient, but less responsive. Twincharger refers to an engine with both a supercharger and a turbocharger.

1

CHAPTER-2 LITERATURE AND SURVEY Nice karim[1] stated in his investigation that A turbocharged engine produces more power overall than the same engine without the charging. This can significantly improve the power-to-weight ratio for the engine (see How Horsepower Works for details). In order to achieve this boost, the turbocharger uses the exhaust flow from the engine to spin a turbine, which in turn spins an air pump. The turbine in the turbocharger spins at speeds of up to 150,000 rotations per minute (rpm) -- that's about 30 times faster than most car engines can go. And since it is hooked up to the exhaust, the temperatures in the turbine are also very high. Veltman thomas[2] stated in his investigation that An ideal solution is to produce small engines which can tolerate high pressure ratios safely, thereby allowing for the greatest reduction in fuel demand during normal operation without sacrificing maximum power production. It is a relatively straightforward engineering task to redesign the engine such that the intake pressure can be raised. It turns out that lowering the compression ratio from 11:1 to 8:1 allows a turbocharger to generate a PR of about 1.6. One could decrease the displacement of the engine by 34% and still achieve the same power. This reduction in compression ratio results in a 10% loss in efficiency. As mentioned above, the turbo itself will increase fuel consumption by approximately 5% owing to exhaust restriction. Borgwarner[3] stated in his investigation that A turbocharged engine's torque characteristic can be improved. Due to the so-called "maxidyne characteristic" (a very high torque increase at low engine speeds), close to full power output is maintained well below rated

2

engine speed. Therefore, climbing a hill requires fewer gear changes and speed loss is lower. The high-altitude performance of a turbocharged engine is significantly better. Because of the lower air pressure at high altitudes, the power loss of a naturally aspirated engine is considerable. In contrast, the performance of the turbine improves at altitude as a result of the greater pressure difference between the virtually constant pressure upstream of the turbine and the lower ambient pressure at outlet. The lower air density at the compressor inlet is largely equalized. Hence, the engine has barely any power loss. Smith robert[4] stated in his investigation that Most automotive turbochargers have a wastegate, which allows the use of a smaller turbocharger to reduce lag while preventing it from spinning too quickly at high engine speeds. The wastegate is a valve that allows the exhaust to bypass the turbine blades. The wastegate senses the boost pressure. If the pressure gets too high, it could be an indicator that the turbine is spinning too quickly, so the wastegate bypasses some of the exhaust around the turbine blades, allowing the blades to slow down. Some turbochargers use ball bearings instead of fluid bearings to support the turbine shaft. But these are not your regular ball bearings -- they are super-precise bearings made of advanced materials to handle the speeds and temperatures of the turbocharger. They allow the turbine shaft to spin with less friction than the fluid bearings used in most turbochargers. They also allow a slightly smaller, lighter shaft to be used. This helps the turbocharger accelerate more quickly, further reducing turbo lag. Nice karim[5] stated in his investigation that The Garrett full ball-bearing turbo is designed to have clearance between the bearing cartridge and center housing for hydrodynamic damping in addition to the internal clearances of the bearing cartridge itself. Hydrodynamic 3

damping uses the incompressible properties of a liquid (oil in this case) and the space around the bearing cartridge to dampen the shaft motion of the rotating assembly. When the turbo is new, or has not operated for a long period of time allowing most of the oil to drain out, the rotating assembly will move more in the radial direction than a typical journal-bearing turbo because there is no oil in the center housing. This condition is normal. As long as the shaft wheel spins freely and the wheels don't contact their respective housings, the assembly will function properly. Richard whitehead[6] stated in his investigation that Forced induction dates from the late 19th century, when Gottlieb Daimler patented the technique of using a gear-driven pump to force air into an internal combustion engine in 1885. The turbocharger was invented by Swiss engineer Alfred Büchi (1879–1959), the head of diesel engine research at Gebrüder Sulzer (now simply called Sulzer), engine manufacturing company in Winterthur, who received a patent in 1905 for using a compressor driven by exhaust gases to force air into an internal combustion engine to increase power output, but it took another 20 years for the idea to come to fruition. The first use of turbocharging technology based on his design was for large marine engines, when the German Ministry of Transport commissioned the construction of the "Preussen" and "Hansestadt Danzig" passenger liners in 1923. Both ships featured twin ten-cylinder diesel engines with output boosted from 1750 to 2500 horsepower by turbochargers designed by Büchi and built under his supervision by Brown Boveri (BBC) (now ABB). During World War I French engineer Auguste Rateau fitted turbochargers to Renault engines powering various French fighters with some success. In 1918, General Electric engineer Sanford Alexander Moss attached a turbocharger to a V12 Liberty aircraft engine. The engine was tested at Pikes Peak in Colorado at 14,000 ft (4,300 m) to demonstrate that it could eliminate the power loss usually experienced in internal combustion engines as a result of reduced air pressure and density at high altitude. 4

Turbochargers were first used in production aircraft engines such as the Napier Lioness in the 1920s, although they were less common than engine-driven centrifugal superchargers. Ships and locomotives equipped with turbocharged diesel engines began appearing in the 1920s. Turbochargers were also used in aviation, most widely used by the United States. During World War II, notable examples of U.S. aircraft with turbochargers — which included mass-produced ones designed by General Electric[10] for American aviation use — include the B-17 Flying Fortress, B-24 Liberator, P-38 Lightning, and P-47 Thunderbolt. The technology was also used in experimental fittings by a number of other manufacturers, notably a variety of experimental inline engine-powered Focke-Wulf Fw 190 prototype models, with some developments for their design coming from the DVL, a predecessor of today's DLR agency, but the need for advanced high-temperature metals in the turbine, that were not readily available for production purposes during wartime, kept them out of widespread use.

[7] In 1918, Sanford Moss, a General Electric engineer on loan to the U.S. Army Air Service and a man with a keen interest in engines, believed he had solved the problem of engine power loss at altitude. In order to demonstrate that his solution would work, he too would find himself climbing Pikes Peak, not to win a race but to perform engine research in the thin air at the summit.

At the time, Moss’ immediate problem was that his solution worked too well. He had built a turbo-supercharger, a device that draws energy from an engine’s exhaust gases to drive a compressor that pumps an extra charge of air to the engine’s intake—supercharging the cylinders. Moss’ device could easily generate the requisite air pressure in the intake manifold of a Liberty test engine, but in U.S. Army tests it caused the fuel-air mixture to ignite prematurely, thereby triggering destructive detonation—a death rattle that could burn 5

or break engine components in seconds. A report filed by two engineers at the Army’s labs at McCook Field in Dayton, Ohio, neatly summed up the problem: “When using the supercharger, 470 horsepower [versus a standard Liberty’s 420 horsepower] was developed at 1700 rpm. It was, however, difficult to make many tests with the supercharger operating. Even when only subjecting the engine to a small amount of supercharge at this low altitude, the spark plugs failed and numerous other difficulties developed.”

Hill climb[8] stated in his investigation that Turbine blades are usually a nickel chrome alloy or a nimonic material (a nickel alloy containing chrome, titanium, aluminium, molybdenum and tungsten) which has good resistance to creep, fatigue and corrosion. Manufactured using the investment casting process. Blade roots are of fir tree shape which give positive fixing and minimum stress concentration at the conjunction of root and blade. The root is usually a slack fit to allow for differential expansion of the rotor and blade and to assist damping vibration. On small turbochargers and the latest designs of modern turbochargers the blades are a tight fit in the wheel.

6

CHAPTER-3 WORKING PRINCIPLE

Fig. 3.1 Turbocharger MORE

FUEL+MORE

AIR=BIGGER

EXPLOSION=GREATER

H.P”

A turbocharger is a small radial fan pump driven by the energy of the exhaust gases of an engine. A turbocharger consists of a turbine and a compressor on a shared shaft. The turbine section of a turbocharger is a heat engine in itself. It converts the heat energy from the exhaust to power, which then drives the compressor, compressing ambient air and delivering it to the air intake manifold of the engine at higher pressure, resulting in a greater mass of air entering each cylinder. In some instances, compressed air is routed through an intercooler before introduction to the intake manifold. Because a turbocharger is a heat engine, and is converting otherwise wasted exhaust heat to power, it compresses the inlet air to the engine more efficiently than a supercharger. The objective of a turbo charger is the same as a supercharger; to improve upon the size-to-output efficiency of an engine by 7

solving one of its cardinal limitations. A naturally aspirated automobile engine uses only the downward stroke of a piston to create an area of low pressure in order to draw air into the cylinder through the intake valves. Because the pressure in the atmosphere is no more than 1 bar (approximately 14.7 psi), there ultimately will be a limit to the pressure difference across the intake valves and thus the amount of airflow entering the combustion chamber. This ability to fill the cylinder with air is its volumetric efficiency. Because the turbocharger increases the pressure at the point where air is entering the cylinder, a greater mass of air (oxygen) will be forced in as the inlet manifold pressure increases. The additional oxygen makes it possible to add more fuel, increasing the power and torque output of the engine. Because the pressure in the cylinder must not go too high to avoid detonation and physical damage, the intake pressure must be controlled by controlling the rotational speed of the turbocharger. The control function is performed by a wastage, which routes some of the exhaust flow away from the exhaust turbine. This controls shaft speed and

regulates

air

pressure

in

the

intake

manifold.

The application of a compressor to increase pressure at the point of cylinder air intake is often referred to as forced induction. Centrifugal superchargers compress air in the same fashion as a turbocharger. However, the energy to spin the supercharger is taken from the rotating output energy of the engine's crankshaft as opposed to normally exhausted gas from the engine. Superchargers use output energy from an engine to achieve a net gain, which must be provided from some of the engine's total output. Turbochargers, on the other hand, convert some of the piston engine's exhaust into useful work. This energy would otherwise be wasted out the exhaust. This means that a turbocharger is a more efficient use of the heat energy obtained from the fuel than a supercharger. Purpose  To increase the output power without disturbing the engine design 8

 To decrease the specific fuel consumption of the engine  To control the air pollution by decreasing the evolution of the exhaust gases Indicated horse power is given as IHP=P L A N K P=EFFECTIVE MEAN PRESSURE L=LENGTH OF STROKE A=AREA OF CROSS SECTION OF CYLINDERS N=RPM OF ENGINE K=NUMBER OF CYLINDERS To increase the indicated horse power without disturbing the engine design mean effective pressure is to be increased. This is achieved by increasing the intake air pressure with the help of super chargers when the turbine is used for the super charging then the system is called turbo super charger.

3.1 MAIN COMPONENTS The turbocharger has three main components:

1. The turbine, which is almost always a radial inflow turbine(but is almost always a single-stage axial inflow turbine in large Diesel engines) 2. The compressor, which is almost always a centrifugal compressor 3. The center housing/hub rotating assembly

9

Many turbocharger installations use additional technologies, such as wastegates, intercooling and blow-off valves.

3.1.1.TURBINE

Fig. 3.1.1 Turbine

Energy provided for the turbine work is converted from the enthalpy and kinetic energy of the gas. The turbine housings direct the gas flow through the turbine as it spins at up to 250,000 rpm. The s ize and shape can dictate some performance characteristics of

10

the overall turbocharger. Often the same basic turbocharger assembly is available from the manufacturer with multiple housing choices for the turbine, and sometimes the compressor cover as well. This lets the balance between performance, response, and efficiency be tailored to the application.

The turbine and impeller wheel sizes also dictate the amount of air or exhaust that can be flowed through the system, and the relative efficiency at which they operate. In general, the larger the turbine wheel and compressor wheel the larger the flow capacity.

3.1.2.COMPRESSOR

The compressor increases the mass of intake air entering the combustion chamber. The compressor is made of an impeller, a diffuser and involute casing.

Fig. 3.1.2 Compressor

3.1.3. CENTER HOUSING

11

The center hub rotating assembly (CHRA) houses the shaft that connects the compressor impeller and turbine. It also must contain a bearing system to suspend the shaft, allowing it to rotate at very high speed with minimal friction. For instance, in automotive applications the CHRA typically uses a thrust bearing or ball bearing lubricated by a constant supply of pressurized engine oil. The CHRA may also be considered "watercooled" by having an entry and exit point for engine coolant. Water-cooled models use engine coolant to keep lubricating oil cooler, avoiding possible oil coking (destructive distillation of engine oil) from the extreme heat in the turbine. The development of air-foil bearings removed this risk.

Ball bearings designed to support high speeds and temperatures are sometimes used instead of fluid bearings to support the turbine shaft. This helps the turbocharger accelerate more quickly and reduces turbo lag. Some variable nozzle turbochargers use a rotary electric actuator, which uses a direct stepper motor to open and close the vanes, rather than pneumatic controllers that operate based on air pressure.

3.2 TYPES SUPER CHARGERS &PERIODICITY OF OVER HAULING Table 3.2.1

OF TURBO

Figure 3.1.3. Center housing

12

MAKE

MODEL

HORSE

COOLING

OVERHAUL

POWER

SYSTEM

PERIODICITY

ABB

VTC304

2600,3100

WATER

2 YEARS

ABB

TPR 61

3100

AIR

6 YAERS

NAPIER

NAP 295

3100,2600

WATER

2 YEARS

GE

SINGLE

3100

WATER

6 YEARS

3100

WATER

6 YEARS

HS 5800

3100

AIR

4 YEARS

720

2600

WATER

1 YEAR

DISCHARGE GE

DOUBLE DISCHARGE

HISPANO SUIZA ALCO

13

3.3.DIFFERENCE BETWEEN TURBO CHARGER AND SUPER CHARGER The design of a turbo charger is very similar to that of the super charger. The difference being one is exhaust driven (turbo) and other is mechanically driven by belt (super charger). The general rule is that a turbocharger maximize power band at higher R.P.M because it is powered by the amount of exhaust being forced through it. On the other hand, a super charger has little low end torque since it is controlled by a belt directly connected to the crank shaft. A super charger is already injecting air in to the system even at extremely low R.P.M. Generally, super chargers cost a little more than turbo kits but a turbo kit is a tougher to install, as you must typically route your exhaust system as well as add an intercooler. In theory a turbo charger is more efficient because it is using the “wasted” energy in the exhaust steam for its power source. on the other hand ,a turbo charger causes some amount of back pressure in the exhaust system and it also tends to provide less boost until the engine is running at higher R.P.M. Super chargers are easy to install but tend to be more expensive.

14

3.4. OVER HAULING PROCEDURE

Unload turbo super charger from loco

Stripping in section

cleaning

inspec tion

assembly

Fit ready turbo charger assembly on loco for final 15

OVER HAULING PROCEDURE Turbocharger Overhauling

Fig.3.4.1.Superturbo charger Tools Required for Dismantling 

Open and ring spanner



Box spanner



Claw spanner



Tommy spanner



Bearing pushing tool

16



Bearing pulling tool



Pump disc locking plate



Pump removing tool set (provided by manufacturer)



Impeller removing tool set (provided by manufacturer )



Shaft pushing tool



Clearance measuring instruments



Screw driver

3.5. PRELIMINARIES BEFORE DISMANTLING: 

Before dismantling, exhaust gas from the turbine should be bypassed and a blanking plate should be fitted in turbine inlet casing.



Drain the lube oil from the built-in sump.



Remove the turbine side cooling water connection and drain all water.

17

Turbine and Impeller

Fig.3.5.1.Turbine

Fig.3.5.2.Impeller

3.6.TURBOCHARGER DISMANTLING PROCEDURE

3.6.1.Compressor Side Removal:

Dismantling should always be started from the compressor side.

1) First remove the filter silencer assembly or compressor inlet casing from position. 18

2) Remove the compressor end cover and drain plug on the compressor side.

3) Remove the suction cover and measure the critical clearance .It is the distance between the compressor end cover mounting face and shaft end .Mark it as K.

4) Pull the rotor shaft towards the compressor side until the impeller comes in contact with the insert and determine K2.

1. Impeller clearance L = K - K2

5) Thrust the rotor shaft towards the turbine side until the turbine disc and nozzle ring comes in contact with each other and measure K1

1. Disc clearance M = K1 - K

6) The above measured clearance is very important as this will determine the proper functioning of the labyrinth seal between the impeller and exhaust shield and also the alignment of the shaft.

7) Remove the lube oil pump assembly after removing the pump locking plate.

8) Remove the bearing nut and bearing nut washer.

9) Fix the bearing pulling tool in position and slowly tighten it. This will pull the ball bearing assembly out. Care should be taken while removing bearing to avoid any damage to the bearing and rotor shaft end threads.

10) Mark the position of the bearing in position to put it back as it is while assembling.

11) The ball bearing assembly should not be disturbed in any case. If it is damaged, the whole assembly should be replaced with the manufacturer's new

part. 19

12) Now remove the compressor outlet casing with diffuser.

13) Remove the impeller nut and impeller washer.

14) Remove the impeller and inducer from position.

Compressor Wheel Before and After Overhauling

Fig.3.6.1 Compressor wheel before overhauling

20

Fig.3.6.1(a)Compressor wheel after overhauling Turbine Blades Before and After Overhauling

Fig.3.6.1(b) Turbine blade before overhauling

Fig.3.6.1(c) turbine blade after overhauling

21

Turbocharger turbine side dismantling procedure for overhauling, for repairing damaged turbine blades, for cleaning cooling water spaces is detailed in the second page of the article "Overhauling and Repair of a Marine Turbocharger." 3.6.2.Turbine Side Removal

1) Remove the turbine end cover with sight glass on the turbine side.

2) Measure the clearance between the turbine end cover mounting face and shaft end.

3) Check the axial deflection of the pump disc cover. The permissible axial deflection of the pump cover is 0.05 mm.

4) Check the rotor shaft by turning by hand.

5) Remove the pump disc locking plate.

6) Loosen the lube oil disc cover and pump washer on the lube oil pump disc by removing the bolt.

7) Remove the outer shaft end nut and tab washer and then remove inner shaft end nut.

8) Remove the lube oil disc from position.

9) Loosen the bearing nut and bearing nut washer and remove from place.

10) Fix the bearing pulling tool on a resilient mounting and slowly tighten it, and this will pull the roller bearing on turbine side slowly out.

11) Care should be taken while removing the bearing to avoid damage to the shaft outer end threads and bearing.

22

12) Do not disturb the bearing assembly as improper bearing position may misalign the rotor shaft.

13) Before removing, put punch mark on the bearing in position so that it can be put back as it is.

14) Remove the turbine inlet casing from the turbine outlet casing.

15) Now the whole rotor shaft can be pulled out from the compressor side. While pulling out the shaft, care must be taken to avoid damage to the turbine blades and labyrinth sealing arrangements on the shaft.

16) Remove tab washer and remove seal plate to the turbine outlet casing.

17) Remove shroud ring and shaft seal from the turbine outlet casing.

18) Remove nozzle ring assembly from the turbine inlet casing.

Finally remove the air seal adjusting screw, anti-corrosion zinc assembly, sand cover, and other various accessories in position.

3.7.TYPES OF CLEANING

3.7.1.Dry cleaning

23

Fig.3.7.1.Dry cleaning of turbocharger

Dry cleaning is carried out using the sand lasting equipment where in highly pressurized abrasive material is forced on to the component which is to be cleaned

3.7.2.Wet cleaning

Wet cleaning is carried out internally and externally. External cleaning is done using fully concentrated CR200 and internal cleaning is done using 10% of trisodiumphosphate with demineralized water using pump at 60 to 80c which is also called descaling.

3.8.INSPECTION

A proprietary nondestructive inspection technique to confirm the presence of cracks in materials using a fluorescent penetrant.

A fluorescent penetrant used to soak the concentrated part for an appropriate length of time, after which the part is rinsed and all penetrant is cleaned off the surface. The part is 24

then placed in a fixture that vibrates and is observed under an ultraviolet light. If the vibration open up a crack that has accepted some of the penetrant, the crack will show up as a glow in black light.

Main steps of liquid penetrant inspection:

3.8.1. PRE-CLEANING:

The test surface is cleaned to remove any dirt, paint, or oil, grease or any loose scale that could either keep penetrant out of a defect, or cause irrelevant or false indications. Cleaning may include solvents, alkaline cleaning steps, vapour degreasing or media blasting the end goal of this step is a clean surface where any defects presents are open to the surface, dry and free of contaminants. Note that if media blasting is used. It may work over small discontinuities in the part and an etching bath is recommended as a post-blasting treatment.

Applications of the penetrant to a part in a ventilated test area.

3.8.2.APPLICATION OF PENETRANT:

The penetrant is then applied to the surface of the item being tested. The penetrant is allowed “ dwell time “ to soak into any flaws ( generally 5 to 30 min ). The dwell time

25

mainly depends up on the penetrant being used, material being tested and the size of flaws sought. As expected, smaller flaws require a longer penetration time. Due to their incompatible nature one must be careful not to apply solvent based penetrant to a surface which is to be inspected with a water washable penetrant.

3.8.3. EXCEESS PENETRANT REMOVAL:

The excess penetrant is then removed from the surface. The removal method is controlled by the type of penetrant used. Water washable, solvent – removable, lipophilic post – emulsifiers or hydrophilic post – emulsifiable are the common choices. Emulsifiers represents the highest sensitivity level and chemically interact with the oily penetrant to make it removable with a water spray. When using solvent on the test surface directly, because this can remove the penetrant from the flaws. If excess penetrant is not properly removed, once the developed area that can make indications or defects. In addition, this may also produce false indications everely hindering your ability to do a proper inspection. Also the removal of excessive penetrant is done towards one direction either vertically or horizontally as the case may be.

3.8.4. APPLICATION OF DEVELOPER: After excess penetrant has been removed a white developer is applied to the sample. Several developer types are available, including non-aqueous wet developer, dry powder, water suspendable and water soluble. Choice of developer is governed by penetrant compatibility ( one can’t use water soluble or suspendable developer with water-washable penetrant) and by inspection conditions. When using non-aqueous wet developer (NAWD) or dry powder, the sample must be dried prior to application, while soluble and suspendable are applied with the part still wet from the previous step. NAWD is commercial available in aerosol spray cans and may employ, or a propellant that is a combination of the two. Developer should form a semi-transparent, even coating on the surface.

26

The developers draws penetrant from defects out on to the surface to form a visible indication commonly known as bleed out. Any areas that can bleed out indicate the location, orientation and possible types of defects on the surface interpreting the result and characterizing the defects from the indication found many require some training and experience.

3.8.5.INSPECTION: The inspector will use visible light with adequate intensity 100 foot candles or 1100 lux is typical for visible dye penetrant. Ultraviolet radiation of adequate intensity along with ambient light levels for fluorescent penetrant examinations inspection if the test surface should take time after 10 to 30 min development time depends on product kind. This time delay allows the bloting action to occur. The inspection may occur the sample for indication formation when using visible dye. It is also good practice to observe indication as they form because the characteristics of the bleed out are a significant part of interpretation characterization of flaws.

CHAPTER-4 DYNAMIC BALANCE

27

Fig. 4.1 Dynamic balancing of super charger

Fig. 4.1.(a) Resultant couple force

A rotating system of mass is in dynamic balance when the rotation does not produce any resultant centrifugal force or couple. The system rotates without requiring the application of any external force or couple, other than that required to support its weight. If a system is 28

initially unbalanced, to avoid the stress upon the bearings caused by the centrifugal couple, counterbalancing weights must be added. This is commonly done, for example: in the case of an automobile tire, where the imbalance is due to imperfections of manufacture that make the tire composition inhomogeneous

Rotating shaft unbalanced by two identical attached weights, which causes a counterclockwise centrifugal couple Cd that must be resisted by a clockwise couple Fℓ = Cd exerted by the bearings. The figure is drawn from the viewpoint of a frame rotating with the shaft, hence the centrifugal forces.

29

4.1 ASSEMBLY

Fig. 4.1.1Bearing housing

Fig. 4.1.2 Turbine in casing

a) fit core hole covers with new gaskets and test to be conducted with 0.2kg/cm b) assemble the turbine end bearing consisting of(bearing housing, end disc and floating bush)and tighten the socket screws and torque 5-8 N.M c) fit the bearing (turbine end with the bearing casing and tighten the socket screws with torque value 25-35NM) d) fit the cover plate and the seal ring cover with new gasket ring in the bearing casing and tighten the hexagonal headed screw to 25to35NM.and lock locking plate discs. e) fit the cap to bearing casing fit lock washers and bolts tighten bolts to 13 to 20 N.M and lock locking plate. 30

f) apply grease to piston ring grove on shaft and fit piston ring in groove properly. g) apply oil to rotor shaft turbine end bearing and insert rotor shaft from turbine side. h) with the extractor carefully slide the trust bearing on the shaft upto the shaft holder from compressor end. i) check the press fit measure ”K” is the distance between the pressed thrust bearing and the shaft end, the limit is 170.50 to 170.65mm. j) assemble the compressor end bearing consisting of plain bearing, auxillary bearing floating bush and tighten the socket screws and locking washers. k) apply oil and fit the compressor end bearing assembling into the bearing casing. l) fit the sealing cover with the gasket into the bearing casing with socket screws and locking washers .torque the screw to 25-35N.M m) the piston ring to be placed correctly and centered with higher vacuum grease in the groove of compressor wheel bush. n) carefully slide the compressor wheel on shaft. o) press the compressor wheel on shaft with help of assembly, disassembly device and hydraulic pump. p) check thrust clearance limit is 0.12 to0.32mm.(0.005” to 9.013”.) q) check radial clearance limit is 0.47 to 0.93mm.(0.19” to 0.037”). r) fit hexagonal headed collar screw and the disc spring tighten hexagonal headed screw to torque 50-80N.Mand tighten cap. s) fit diffuser to compressor outlet causing and tighten screws. 31

t) fit air outlet casing assembly on bearing casing with hex headed screw and lock washer, tighten the bolt to 45 to 70N.M. u) fix nozzle ring in gas inlet casing with hex headed bolts with locking plate tighten the bolt to 25 to 35N.Mand lock the lockplate. v) fix the cover ring in gas inlet casing assembly into gas in let casing. Fix hex headed screw with locking plate, tighten the hex screw to 25 to 35 N.M and provide lock plate. w) fit chimney on turbine casing with gasket and tighten the hex headed screw 45 to 75N.M. x) before coupling on loco, check water oil pipelines for condition change in necessary. y) the following new gaskets to be fitted.1)turbo to manifold gasket,R1and L1bellow gasket.2)turbo to after cooler expansion joint rubber ‘0’ ring and gasket. z) lift the turbo with sling and with overhead crane and lower the turbo on loco. The following connecting to be given. 1) turbo to manifold. 2) R1 and L1 bellow connector. 3) turbo to after cooler expansion joint connections. 4) water pipe line connection. 5) lube oil pipe line connection. 6) turbo foundation bolt to be tightened. 7) clamps to be provided to water and lube oil pipes.

CHAPTER-5 32

ADVANTAGES

AND

DISADVANTAGES

OF

TURBO

SUPERCHARGER 5.1.Advantages If you charge added power, again it is accessible for you to use. Depending aloft the kit and added add-ons, you can see up to a 40% access in power. This can be absolutely accessible for casual someone, traveling up long, abrupt roads, or if you reside in a aerial area.

Decrease in emissions. Accompanying turbo kits use the bankrupt (wasted energy), to actualize new activity (compressed air) to ability the turbo. Essentially it is a anatomy of recycling. By application the exhaust, instead of just spewing it out, you are abbreviating your

carbon

emissions,

which

is

acceptable

for

the

environment.

With decreased emissions, and recycling the exhaust, you should see an access in your gas mileage, and that is consistently a plus! It has been estimated that you can get up to 20% bigger ammunition economy. So you are accepting both added ability and added ammunition efficiency.

Twin turbo kits, back they accept two turbochargers, reduces the lag time that it takes the agent to ball up and be accessible to action properly. Basically, this agency that you can get

up

to

turbo

speeds

quicker

than

a

approved

turbo

charger.

33

5.2.Disadvantages They do not accommodate an actual ability addition if you footfall on the gas. It takes a moment for the addition to bang in, but as mentioned above, this bulk of time is bargain with accompanying turbo kits. If the turbo engine does bang in, you may feel a lurch.

If you accept a fuel-injected engine, you may accept to do added modifications to access the ammunition arrangement to access the best account of the Turbocharger. This may be all-important because sometimes in the fuel-injected engine, the arrangement that controls the ammunition to oxygen allowance can malfunction and not accommodate abundant ammunition to the turbo engine. This does not consistently happen, but is acceptable to be acquainted of as a aboriginal affair to analysis if you do not get the accepted performance.

34

CHAPTER-6 TROUBLES AND TROUBLE SHOOOTING Exhaust gas temperature higher than normal

With unchanged output and engine speed. High temperature of incoming air when running without charge air cooler

Engine  Fault in injection system  Air receiver leaking  Gas leakage between engine and turbine

Turbo charger  Lack of air,e.g.filter choked with dirt  Dirty compressor  Exhaust back pressure too high  Turbine blade damaged

Charge air cooler  Dirty insufficient water, temperature of cooling water too high  Insufficient venting

Charge air pressure lower than normal

With unchanged output and engine speed and normal intake conditions

35

Turbocharger  Pressure gauge reading wrong  Dirty air filter accounting for pressure drop  Labyrinth seals damaged  Blading of nozzle ring damaged  Exhaust back pressure too high

Charge air pressure higher than normal

With unchanged output and engine speed and normal intake conditions

Vibrations due to revolution frequencies of the turbo charger rotor  Unbalancing of rotor as a result of severe dirt in the compressor or the turbine  Damage turbine blading or damping wire  Defective bearings

Noise during run out, run out time too short or hesitant runup  Damaged bearings.  Rotor touting  Turbo charger dirty  Foreign bodies inside the turbo charger

36

Leakage from casing  Cracks are produced by the thermal stresses due to  -lack of air relief  -lack of cooling water  -excessive furring

Loss of lubricating oil  Damaged or worn out piston rings  Opening to the seating air ducts blocked  damaged gasket rings

Repeated surging by the turbo charger  increased air flow resistance ex.due to dirt in the charge-aircooler,the silencer,the compressor or the turbine  detective non return valves on two stroke engine

37

CHAPTER-7 CONCLUSION Despite of its disadvantages the necessity of a turbo super charger has increased in modern day to day to life because of many advantages like decreasing in pollution, decrease in specific fuel consumption high H.P without changing engine design.

As most of the parts are imported from abroad countries like U.S.A, france, cost of turbo increased many more times than production cost. so government of India should take measures to encourage entrepreneurs in this field.

As it is mandatory for doctors to serve one year in rural areas such laws should be even implemented to engineers as to work in any government industry of his specialization atleast for an year .So that he will encounter practical problems and ability to solve them.

38

REFERENCE [1] Nice, Karim (4 December 2000). "How Turbochargers Work" (http://auto.howstuffworks.com/turbo.htm).Auto.howstuffworks.com. Retrieved 1 June 2012. [2]Veltman, Thomas (24 October 2010). "VariableGeometry Turbochargers"(http://large.stanford.edu/courses/2010/ph240/veltman1/). Coursework for Physics 240. Retrieved 17 April 2012. [3] "BorgWarner turbo history" (http://www.turbodriven.com/en/turbofacts/default.aspx). Turbodriven.com. Retrieved 2 August 2010. [4] Smith, Robert (January–February 2013). "1978 Kawasaki Z1RTC: Turbo Power" (http://www.motorcycleclassics.com/classicjapanesemotorcycles/ kawasakiz1rtczm0z13jfzbea.aspx). Motorcycle Classics 8 (3). Retrieved 7 February 2013. [5]Nice, Karim."How Turbochargers Work" (http://auto.howstuffworks.com/turbo3.htm). Auto.howstuffworks.com. Retrieved 2 August 2010. [6] Richard Whitehead (25 May 2010). "Road Test: 2011 MercedesBenz CL63 AMG" (http://www.thenational.ae/lifestyle/motoring/roadtest2011mercedesbenzcl63amg). Thenational.ae. Retrieved 1 June 2012. [7] Turbocharger From Wikipedia, the free encyclopedia‖ http://en.wikipedia.org/wiki/Turbocharger#History Retrieved 4 july 2015. [8] "Hill Climb" (http://www.airspacemag.com/historyofflight/climb.html?c=y&page=1). Air & Space Magazine. Retrieved 2 August 2010. 39