Aditya Korla Branch – Mech.Engg. Sem. – 5th Roll No. 6512303
MECHANICAL ENGINEERING PANCHKULA ENGINEERING COLLEGE MOULI, BARWALA, PKL
TO WHOM IT MAY CONCERN
This is certified that Mr. Aditya Korla Son of Sh. Bal Mukund Korla has completed 45 days training in this Establishment form 24-07-2014 to 0309-2014 during the above period his conduct found very good.
Topics Acknowledgement Introduction Setting Up Operation Operational activities Introduction about work shop Safety Guidelines Main Components of automobile Clutch system Parts of gear box Differential Alternator Fuel Pump Various working system in automobile Calibration pump Reason of troubles in various parts in vehicle Inspection after every 72000 km Brakes Lathe Bibliography Conclusion
This report is a result of my industrial training held at H.R.T.C Workshop, Dharamshala . I thanks to Vivek
important factor for me to complete my report successfully. I also thank to the whole working staff of workshop specially Balbir Singh head mechanic
knowledge during the training period.
INDRODUCTION As stated in our syllabus we have prepared our project on our industrial training. As being mechanical student in present contest we need to be acquainted with practical exposure about auto components, industrial field procedure and comprehensive approach regarding concepts in the classroom and their application involving industrial/field task problem.
To have first hand knowledge industrial culture and to mentally prepare them before joining world of work service. So for this very purpose I want H.R.T.C to winterfeed with workers thought queries. On feedback we prepare following report such as specification, various parts etc. Is about TATA and ASHOKA LEYLAND.
On feedback we prepared following report. All data taken in this report such as specifications, various parts etc.are about TATA LP/LPO 1512 TC vehicle by TELCO where quality is the watchword.
SETTING UP At the time of Independence, Himachal was formed as a “C” class state by merger of 33 hilly states of North –Western Himachalayas on 15 th April, 1948. Passenger and goods services were nationalized in the Pradesh in july,1949.During the year 1958, a Corporation, “Mandi-Kullu Road Transport Corporation” was floated jointly by the govt. of Punjab,Himachal and Railways under the Road Transport Corporation Act, 1950 Basically to operate on the joint routes in the states of Punjab and Himachal.with the re-organization of Punjab State in 1966, few hilly areas of Punjab were merged in Himachal and operational areas of Mandi-Kullu Road Transport Corporation came entirely in the expanded state of Himachal. On 02.10.1974,Himachal Govt. Transport was merged with Mandi-Kullu Road Transport Corporation and was renamed what even today is known as Himachal Road Transport Corporation.
After the formation of Himachal on 15 th July, 1948 the network at roads had received top-most priority of the Government. At Present the road network is widely spread in Himachal.In 1974 total routes operated by HRTC were 379 which have grown to 1967 in 2007-2008 and fleet strength has grown from 733 to 1881 in 2009-2010. Bus remains the sole mode of passenger transportation in the state as railways have a negligible presence in the state. The narrow gauge lines connecting Pathankot with Joginder Nagar and kalka with Shimla are so slow moving that a very small percentage of traffic is carried by them at present; Thereby leaving the onus of carrying the passenger traffic on to bus transport. The growth of HRTC viz-a –viz its formation is as under:-
OPERATION Himachal is geographically so situated that it has got three different regions viz. high hills in linner Himalayas, mid –Himalayan ranges and foothill plains. The linner Himalayan ranges have the least population density whereas it increases as the height decreases being well populated in the foothill plains. Thus, traffic density is accordingly dictated and so is the road network .The operation of HRTC expanded as the road network expanded or enlarged in the last 50 years leading to expansion in its fleet.
The top priority that the state Govt. had, from one plan to another, was to connect far flung areas of the Pradesh so that the road transport could become basic infrastructure for development. The case in example is the expansion of road network in the apple belt in Himachal; where large tracks of land came under orchards and to unload to its produce in the market. As a result, a wide network of road was built in the last 50 years which not only provided the mode of transportation for the farm produce, but also the infrastructure for essential services like education, health etc. The hardship that the HRTC encountered was that its operation expanded more in the far flung areas and on newly constructed roads which led to less utilization of stock, higher expenses on operation and lass yield in revenues. Case in example, is the HRTC operation in tribal areas of H.P. Viz. district of kinnaur, district of Lahaul & Spiti and Pangi and Bharmour Sub-divisions of Chamba district. During early sixties, disassembled jeeps were taken across Rohtang Pass (13,000 Feet height), reassembled within the valley and then operated as buses. Inputs for operation like fuel, spare-parts were carried on human backs to the valley. At present,
thought a road exists across the Rohtang Pass, which closes to traffic from October to June whereas the valley remains open for operation till December and reopens for operation in April.
Even today, the operations in the valley of Pangi are met with there mini buses and jeeps. In the socio-economic situation that accrue in the state today, one cannot think of economics of operations as the benefits that accrue to the people by the bus services are of vital importance to the economy of these areas.
OPEARTIONAL JURISDICTION The operation jurisdiction of the Corporation is divided into four Divisions (Located at Shimla,Mandi, Dharamshala and Dharamshala) having 23 depots (Located
Besides its operation in the entire Himachal Pradesh including tribal districts of the state, HRTC operates its buses in neighboring states of Punjab, Haryana,Rajasthan, Uttar Pradesh, Jammu & Kashmir ,Union Territories of chandigrah and Delhi. Further, it has acquired distinction to ply its buses to the highest village of the Asia and also its buses cross through the three worlds highest passes namely; Bara-Lacha, Kunjam and Rohtang .HRTC is plying its buses in remotest area of the Pradesh, which includes Kuchha and Dangerous roads, where private operators hesitate to ply the buses.
INDRODUCTION TO WORKSHOP
Workshop is a place where various components are repaired and manufactured. In the H.R.T.C workshop the various parts like engine, gear box, wheel system, differential, battery etc. Are repaired or tested, for the good and long running of the vechile.the testing of vehicle is also necessary for the safety of the people. Therefore in every gap of one year the buses are passé here. It is also a place where the skills of the out coming engineers and mechanics can be developed. The efficient use of fuel and given resources is also taken in to consideration. Hence workshop is of utmost importance keeping the safety of the passengers and efficient management of H.R.T.C.
SAFETY GUIDELINES To avoid accident and to keep them from happening following safety guidance should be followed:-
1) Provide your attention at most to the Job and work quietly. 2) Keep the tools with in your convenient reach. 3) Be serous about your never including in horseplay or other foolish activities to avoid injury to others. 4) Never put sharp objects like screw driver in your pocket otherwise you will cut yourself. 5) Always wear suitable clothes and shoes while entering the workshop. 6) To provide good drip on the tools or parts always wipe excess oil and grease up fly our hand tool. 7) To avoid one slipping and falling to the ground due to split of oil, grease or any other liquid clean up immediately. 8) Compressed air should never be used to blow dust from your clothes. Compressed hose should never be pointed to any person because flying particles.
MAIN COMPONENT OF AN AUTOMOBILE ENGINE
Sr.No Mech. Components 1) Cylinder
Fuel system Fuel Tank
Lubricating system Oil Pan
Cooling System Radiator Rubber hose connectors Water Pump
Exhaust System Exhaust Manifold Exhaust Pipe Muffler
Helper spg. Torsion unit a) Rubber b) Torsion Unit
OTHER COMPONENTS 1. Turbocharger 2. Cover Over which (TVs , boh) 3. Fuel Injector 4. Thermostatic valve 5. Oil Pump 6. Starting Motor are self 7. Fuel injection pump 8. Feed pump
9. Dawn plug (lubrication oil out ) 10. Thrust bleeding
UPPER PART 1. Valve mechanism 2. Spring shut 3. Springs 4. Valve Spring 5. Valve shut 6. Push Rod 7. Tapper 8. SIDE PART 9. Charger 10. Turbo 11. Water pipe
MIDDLE HOUSING 1. York Thrust reverses bearing 2. Reverse plate and clutch
CLUTCH SYSTEM Clutch is the mechanism interposed between engine and the gear box which enables power as torque of the transmitted at the WILL to the gear box through friction drive. When clutch pedal is depressed the clutch is disengaging and motion and power flow from engine to gear box and hence to road wheels is disconnected.
IMPORTANT FUNCTION OF CLUTCH WITHIN THE POWER TRAIN
MOVING THE VEHICLE FORM REST
Engine gives sufficient power required for moving the vehicle from rest only at higher rpm. Therefore it is necessary to run the engine on no load up to such rpm and then connect to gear box .This is achieved by disengaging the clutch upon which engine is separated from gear box.
SHIFTING IN THE GEAR
While changing gear it is necessary that the gear5 in the box should not be under the load of transmitted power there for during each up or down gear
shift it is necessary to interrupt power flow from engine to the gear box this is achieved by disengaging clutch before shifting in to gear.
PROTECTION WITH IN THE POWER TRAIN
Clutch is the only flexible link between the engine and the power train as the poor transmission is only through is only through the friction drive. There is no grid connection between driving and driven members which provides safety within the power train against the load or transmission.
PARTS OF GEARBOX MAIN SHAFT It is directly connected to engine gears are mounted over it. 1st speed gear 2nd speed gear 3rd speed gear 4th speed gear
Deferential part of gear box. Function of each parts with material and location
Housing and support for the gear act as reservoir of oil
It is the shaft which is directly connected to the engine and gears are mounted on it.
This shaft lies just below the primary shaft and this shaft is responsible for the changing of gears which transmits the power at different speeds.
Top and side view of a typical manual transmission, in this case a Ford used in cars with external floor shifters.
Modern gear boxes are constant mesh, i.e. all input and drive gears are always in mesh. Only one of these meshed pairs of gears is locked to the shaft on which it is mounted at any one time, while the others are allowed to rotate freely. This greatly reduces the skill required to shift gears. Most modern cars are fitted with a synchronized gear box, although it is entirely possible to construct a constant mesh gearbox without synchromesh, as found in a motorcycle, for example. In a constant mesh gearbox, the transmission gears are always in mesh and rotating, but the gears are not rigidly connected to the shafts on which they rotate. Instead, the gears can freely rotate or be locked to the shaft on which they are carried. The locking mechanism for any individual gear consists of a collar (or “Dog Collar”) on the shaft which is able to slide sideways so that teeth circumference: one attached to the gear, one to the shaft (one collar typically serves for two gears; sliding in one direction selects one transmission speed, in the other direction selects the other). When the rings are bridged by the collar that particular gear is rotationally locked to the shaft and determines the output speed of the transmission. The modern cone system was developed by Porsche and introduced in the 1952 Porsche 356; cone synchronize were called “Porsche – type” for many years after this. In the early 1950s only the second-third shift was synchromesh in most cars, requiring only a single synchro and a simple linkage; driver’s manuals in cars suggested that if the driver needed to shift
from second to first, it was best to come to a complete stop then shift into first and start up again. With continuing sophistication of mechanical development, however fully synchromesh transmission with three speeds, then four speeds and then five speeds, became universal by the 1980s. Many modern manual transmission cars, especially sports cars, now offer six speeds.
SYNCHROMESH GEAR BOX
If the teeth, the so-called dog teeth, make contact with the gear, but the two parts are spinning at different speeds, the teeth will fail to engage and a loud grinding sound will be heard as they clatter together. For this reason, a modern dog clutch in an automobile has a synchronizer mechanism or synchromesh, which consists of a cone clutch and blocking ring. Before the teeth can engage, the cone clutch engages first which brings the selector and gear to the same speed using friction. Moreover, until synchronization occurs the teeth are prevented from making contact, because further motion of the selector is prevented by a blocker (or “Baulk”) ring. When synchronization occurs, friction on the blocker ring is relieved and it twists slightly, bringing into alignment certain grooves and notches that allow further passage of the selector which brings the teeth together. Of course the exact design of the synchronizer varies from manufacturer to manufacturer. The synchronizer has to change the momentum of the entire input shaft and clutch disk. Additionally it can be abused by exposure to the momentum and power of the engine itself, which is what happens when attempts are made to select a gear without fully disengaging the clutch. This cause extra wears on the rings and sleeves reducing their service life.
When the bus is taking the turn the outer wheel will travel greater distance as compared to inner wheel in the same time if there fore the bus has a solid rare axel only and no other device there will tendency of the wheel to skit. Hence of the wheel skidding is to be avoided some mechanism must be incorporated in the rear axel which should reduce the speed of the inner wheel and increase the speed of the all wheels when going straight a head such advice is known as differential.
MAIN PARTS OF DIFFERENTIAL
1. Crown wheel 2. Sun gears 3. Star Gears 4. Axel Shafts 5. Casing of differential
Diagram showing alternator used in the TATA buses
This 3 HA 15 alternator is a 12 pole 3 phase machine of revolving field with stationary armature type. The machine which is ventilated design is cooled by means of a fan mounted on the rotor shaft at the end.
Rated Voltage system
Maximum operating speed
Cut in Speed
Direction of rotation
Clock (viewed pulley end)
FUEL PUMP PARTS OF FUEL PUMP 1. Delivery valve, Holder inside big Spring 2. Spring , upper plate, sleeve 3. Pump housing 4. Governor Housing 5. Governor 6. Cam Shaft 7. Bearing and bearing number 62203 and 62204. 8. Control rack 9. Stop Lever 10. Fulcrum lever 11. Guide bush 12. Cycle 13. Tapped roller assembly 14. Spring 15. Delivery valve holder element
16. Delivery valve (a) Upper Plate (b) Lower plate 17. In line pump more than one cycle or two cycles 18. Pneumatic governor 19. Mechanical Governor (RSV, RQ, RQV Governor).
ROBERT BOSCH TYPE VE DIESEL INJECTION PUMP For many home mechanics the diesel injection pump is a bit of a mystery. The Bentley and Haynes repair manuals doesn’t describe its internals, because it’s not serviceable except by a few diesel specialists learning some basics of how it works and what its internals are could be of interest to the diesel owner, and the knowledge certainly can’t hurt when troubleshooting fuel injection problems, even if one isn’t about to take the pump apart.
The purpose of the fuel injection pump is to deliver an exact metered amount of fuel, under high pressure at the right time to the injector. The injector, unlike in a gasoline engine, injects the fuel directly into the cylinder or a prechamber connected to the cylinder.
The Bosch VE has comparatively few moving parts, but what does move does so in a complex way. The figure to the left is from a Yanmar pump, which works and looks the same as the Bosch. On the leftmost end in the picture is the fuel feed pump. This is a vane pump, just like the vacuum pump on the VW diesel engine. Its purpose is to suck fuel from the tank and deliver it to the metering pump. All the things shown on the right in the figure have to do with the metering, timing and distribution of fuel delivery. The figure below shows this part in detail.
The plunger (right middle in the figure) in the VE pump both rotates along its axis and performs a reciprocating translation in and out. It is the translation that performs the high pressure pumping, while the rotation is responsible for metering and sending the fuel to the correct cylinder.
The cam disk is rigidly attached to the plunger. The drive shaft rotates the cam disk. The cam disk rides on four rollers (only one shown in this picture), and has four lobes. Thus for each revolution the plunger will pump four times. Note that with this arrangement the plunger stroke is constant. The metering (regulation of how much fuel is delivered) is done not by changing the mechanical stroke, but by spilling some of the fuel through spill ports, and thus changing the effective stroke . This is done by uncovering a spill port under the control sleeve at a particular angle of rotation. The other purpose of the rotation is to deliver the fuel to the correct cylinder. This is done by having four four delivery valves (only one shown in the figure), one for every 90 degrees of rotation. During a full revolution the plunger makes four strokes, one at 0, 90, 180 and 270 degrees.
During each stroke the delivery port in the middle of the plunger is connected to a particular delivery valve. To understand the function in some detail lets consider one stroke. During the backward motion of the plunger, the rotation uncovers a fill port (to the right in the figure, just below the magnet valve (solenoid)), and the plunger barrel is loaded with fuel. At bottom dead center the fill port is closed. On the forward pressure stroke fuel is pressurized (to over 120 bar). At this time the Plunger barrel is connected to a particular delivery valve through the channel in the center of the plunger, and a port in the side. When pressure builds up to the delivery valve opening pressure, the valve will open and deliver high pressure fuel to the injector. When the desired amount of fuel has been injected the spill port opens (located under the control sleeve in the figure), and the pressure quickly drops. This causes the delivery valve to close. During the rest of the stroke fuel is "spilled" through the spill port instead of being injected into the cylinder. The position of the control sleeve controls at what angle the spill port opens, and thus determines the amount of fuel injected, in other words it controls the metering. The control sleeve is moved in response to a combination of accelerator position and engine speed. The latter is determined by a mechanical governor.
OTHER FUNCTIONS Some other functions of the fuel injection pump are:
Timing The timing is adjusted in response to engine RPM. At higher RPM s, the fuel pressure from the vane transfer pump is higher. Pressure changes effects a spring loaded plunger, and the resulting movement will move the cam rollers to either advance or retard the timing. There is also a cold start device which advances the idle timing manually.
Governor A mechanical governor limits the maximum speed of the engine to 4800 rpm in the bus/vanagon application and 5350 rpm in newer passenger cars. It can be seen just above the cam disk in the middle figure.
Stop A magnet valve or solenoid (shown in the figures) opens and shuts off the fuel channel between the feed pump and the metering pump.
Aneroid An air inlet pressure sensor is used to determine maximum amount of fuel delivered on injection pumps for turbo engines. On newer ('89 and later) naturally aspirated engines a similar arrangement is used for altitude compensation.
VARIOUS WORKING SYSTEMS IN AUTOMOBILE IGNITION SYSTEM This system is responsible for the ignition of the engine As we know that engine require ignition for the star. Alex is used in buses
FUEL INJECTION Injectors are used to inject the fuel into the engine cylinder.
TRANSMISSION SYSTEM Various transmission systems are clutch, gear box, propeller shaft, and differential.
LUBRICATION SYSTEM Lubrication system is employed for lubrication process. It reduces the frictional losses.
COOLING SYSTEM Radiator is used to cool engine and a fan is used just back of radiator. Cooling is necessary for engine as it goes on heating and this heating can cause damage to the engine.
EXHAUST SYSTEM This system removes the gases from cylinder due to which the process continues. Silencer and turbo are used in diesel engine for the removal of exhaust.
SUSPENSION SYSTEM Suspension system is responsible for the smooth drive of vehicle on road. These are vob. Dampers, leaf springs, and air suspension etc.
POWER STEERING There are a couple of key components in power steering in addition to the rackand-pinion or recalculating-ball mechanism.
PUMP The hydraulic power for the steering is provided by a rotary-vane pump (see diagram below). This pump is driven by the car's engine via a belt and pulley. It contains a set of retractable vanes that spin inside an oval chamber. As the vanes spin, they pull hydraulic fluid from the return line at low pressure and force it into the outlet at high pressure.
The amount of flow provided by the pump depends on the car's engine speed. The pump must be designed to provide adequate flow when the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is running at faster speeds. The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at high engine speeds when so much fluid is being pumped.
ROTARY VALVE A power-steering system should assist the driver only when he is exerting force on the steering wheel (such as when starting a turn). When the driver is not exerting force (such as when driving in a straight line), the system shouldn't provide any assist. The device that senses the force on the steering wheel is called the rotary valve. The key to the rotary valve is a torsion bar. The torsion bar is a thin rod of metal that twists when torque is applied to it. The top of the bar is connected to the steering wheel, and the bottom of the bar is connected to the pinion or worm gear (which turns the wheels), so the amount of torque in the torsion bar is equal to the amount of torque the driver is using to turn the wheels. The more torque the driver uses to turn the wheels, the more the bar twists. The input from the steering shaft forms the inner part of a spool-valve assembly. It also connects to the top end of the torsion bar. The bottom of the torsion bar connects to the outer part of the spool valve. The torsion bar also turns the output of the steering gear, connecting to either the pinion gear or the worm gear depending on which type of steering the car has.
As the bar twists, it rotates the inside of the spool valve relative to the outside. Since the inner part of the spool valve is also connected to the steering shaft (and therefore to the steering wheel), the amount of rotation between the inner and outer parts of the spool valve depends on how much torque the driver applies to the steering wheel. When the steering wheel is not being turned, both hydraulic lines provide the same amount of pressure to the steering gear. But if the spool valve is turned one way or the other, ports open up to provide high-pressure fluid to the appropriate line. It turns out that this type of power-steering system is pretty inefficient. Let's take a look at some advances we'll see in coming years that will help improve efficiency.
Recalculating-ball steering is used on many trucks and SUVs today. The linkage that turns the wheels is slightly different than on a rack-and-pinion system.
The recalculating-ball steering gear contains a worm gear. You can image the gear in two parts. The first part is a block of metal with a threaded hole in it. This block has gear teeth cut into the outside of it, which engage a gear that moves the pitman arm (see diagram above). The steering wheel connects to a threaded rod, similar to a bolt that sticks into the hole in the block. When the steering wheel turns, it turns the bolt. Instead of twisting further into the block the way a regular bolt would, this bolt is held fixed so that when it spins, it moves the block, which moves the gear that turns the wheels.
Instead of the bolt directly engaging the threads in the block, all of the threads are filled with ball bearings that recalculate through the gear as it turns. The balls actually serve two purposes: First, they reduce friction and wear in the gear; second, they reduce slop in the gear. Slop would be felt when you change the direction of the steering wheel -- without the balls in the steering gear, the teeth would come out of contact with each other for a moment, making the steering wheel feel loose. Power steering in a recalculating-ball system works similarly to a rack-andpinion system. Assist is provided by supplying higher-pressure fluid to one side of the block.
Now let's take a look at the other components that make up a power-steering system.