Automobile Notes

7/28/2019 Automobile Notes

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Chapter 1 : Introduction and the Chassis Construction

Very Short Answer Type Questions

Q. 1. Name distinct types of suspension system.Ans . 1. Conventional system : In this system springs are attached to a rigid beam2. Independent system : In this each wheel is free to move vertically without any reactionon the other wheel and there is no rigid axle beam.

Q. 2. What is the function of universal joint?Ans. The function of universal joint is to provide relative motion between the engine andthe driving wheel.

Q. 3. Classification of automobiles.Ans . Automobiles are classified according to:1.Use2. fuel3. Capacity4. Body style5 Wheels6 Make and model7 Transmission8. Drive.

Q. 4. What is the function of the frame.Ans. 1. To support the chasis, components and the body.2. It offers resistance to deflection due to static and dynamic loads acting on frame.

Q. 5. What is the material of clutch facing ? What is the function of Hooke oruniversal joint.Ans . Generally following types of clutch material are used in clutches.(a) Leather(b) Cork(c) Cotton fabric(d) Asbestos etc.Universal Joint (Hookes Joint). It is a joint in a rigid rod that allows the rod to bend anydirection and is commonly used in shafts that transmit rotary motion.

Q. 6. Why we provide Gear box in a vehicle?Ans . Gear box provides the required lenarage variation between the engine of vehicle androad wheels.

Q. 7. What are the functions of a frame?Ans. 1. It support the chasis components installed on vehicle and the body.2. It also helps to withstand static and dynamic deflection due to load and road conditionsbetter.

Q. 8. Why frame is narrow at the front?Ans . Frame is narrow at the front to provide latter steering lock, so that turning radiusshould be small or minimum.

Q. 9. Which section of frame offer maximum resistance to Torsion and bending.Ans . Frame with X-member provide better resistance to twisting or torsion effect. where asto resist bending moment, frame should have double section frame.

Q. 10. What types of components are mounted on the chasis frame?Ans .1.Engine and radiator.2.Transmission system


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3.Suspension system4.Road wheels5.Steering system6. Brakes.

Q. 11. What do you under stand by frameless frame?Ans. Frameless frame are those frames in which floor is strengthed by cross members andthese member is welded together. Some time according to requirement sub members are

also used.Q. 12. Name common defects in frames ? What are various types of rear axles.Ans. 1. Rivets may be loose or broken.2. Misalignment of members after accident. Types of Rear Axle : Semi floater, full floater.

Short Answer Type Questions

Q. 13. Explain the method for checking the alignment of chasis frame?Ans . Misalignment in vehicle takes place some time due to accident or due to unevenstaking of load on vehicle, this is checked by mean of plumb line.

Q. 14. What are the advantages of four wheel drive over two wheel drive.Ans. 1. Main advantage of four wheel drive is that when front wheel fall into ditch,they can be driven out from ditch by rear wheel power because vehicle isfour wheel drived.2. In plain roads four wheel drive can be changed to 2-wheel drive when not required bytransfer beam. By this way fuel efficiency is increased.3. Four wheel drive is beneficial in hilly areas as well in muddy areas because there isrequirement of more power than planes, which is in four wheeldrive.

Q. 15. Write short note on subframes?Ans. In normal vehicle various component are bolted on the main frame. But some timecomponent on vehicle is installed on the subframe which are bolted on the main frame.Subframe provide greater strength, more over it is supported at three points on the mainframe.The advantage of subframe is that component bolted on the subframe are isolated from themain frame upon which various types of forces act like twisting bending forces. It reducesthe vibration. It also helps to simplify the overhead or repair and increases the production of vehicle in assembly line.

Q. 16. What do you mean by transmission system?Ans . Transmission system consists of clutch, gear box giving different types of ratios of torque output to applied input. The output torque is then transmitted to gear beam and thento differential beam from which it is transfers to in rear wheel if vehicle is in rear wheeldrive. It transmits the required torque according to the vehicle drive. So it is a main partwithout which we cannot imagine variation of speed and torque.

For checking vehicle it should be placed on level surface and then suspend plumbline from four different corners. Mark the point on ground. Then check the diagonals of fourpoint marked on ground. It should not be differ by 7 to 8 mm. If difference is more thanpercribed limit then frame is misaligned.

Long Answer Type Questions

Q. 17. Explain in detail how to classify the automobiles?Ans. Automobiles can be classified by considering the following points.1. Use:(a) Auto, cycles, Buses, Car, Jeeps etc.2. Make and model:1. In two wheel section major companies are (a) Bajaj Autos (b) Honda (c) LML.


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2. Where as in four wheel.(a) Honda city(b) Maruti Suzuki(c) Fiat(d) Mahindra.

3 . Heavy transport vehicle (H.T.V.)(a) Tata, (b) Leyland (c) General motors (d) Nissan etc. 3. Capacity:(a) (H.T.V.) Heavy transport vehicle like buses and trucks, trailors.

(b) (L.T.V.) Light transport vehicles, like cars, jeeps etc.4. Fuel used:(a) Petrol vehicles : In which fuel used is petrol e.g., Scooters, cars, motors cycles etc.(b) Diesel vehicles : In which fuel used is Diesel e.g. Buses, Trucks etc.5. Body Style : According to Body style following are major styles.(a) Closed car like, saloons, couple etc.(b) Open cars like, sport cars, convertible cars.,(c) Special style vehicle like, estate car, station wagon etc.6. Wheels:1. Two wheelers - Scooters, motor cycles.2. Three wheelers - Auto richshaws.3. Four wheelers - Cars, jeeps.

4. Six wheelers and above in buses.5. Truckes trailors.7. Drive:1. Left hand drive - In foreign country mostly L.D.D. is true.2. Right hand drive - In India right hand drive vehicle are used.3. Front wheel drive - Maruti cars, Vaibs wagon4 Rear wheel drive - Trucks, Buses5 Four wheel drive - like Jeep, military trucks8 Transmission Type1 Conventional Gears In which ordinary gear beam is fitted2 Semi automatic gears In which combmation of manual plus some automaticmachines is there.

3. Fully automatic : In which vehicles are fully equipped with full automatic transmissionsystem by using epicyclic gears and torque convertors.

Q. 18. Differentiate between the functions of Spring and Shock absorber.Ans. The spring support the weight of the vehicle and absorb road shocks. It is of four types coil, leaf spring, air spring and torsion bar.Shock absorbers help control spring action. Different types of shock absorbers arespring assisted, adjustable and air shock absorbers.

Q. 19. Write note on layout of automobile vehicle.Ans . Layout of Automobile Vehicle.In automotive design the automobile layout describes where on the vehicle the engine anddrive wheels are found. Many different combinations of engine location and driven wheelsare found in practice. Factors influencing the design choice include cost, complexity,reliability, packaging, weight distribution and the vehicles intended handling characteristics.Layouts can roughly be divided into two categories : front- or real-wheel drive.


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Chapter 2 : Fuel Supply System


Q. 1. What is the function of injector?Ans. It is also known as atomizer or fuel pump and nozzle Main function of injectoris to inject the fuel in the cylinder in the atomised form in proper quantity.

Q. 2. What is the function of injection pump?Ans. The function of injection pump is to supply correct quantity of fuel to the injectorunder high pressure at the correct instant and in the correct sequence.

Q. 3. What are the types of oil supply systems?Ans. Following are the different types of oil supply systems.1. Gravity system2. Pressure3.Vacuum4. Pump5. Fuel injection system.

Q. 4. What are the basic functions of a carburettor? Define carburetion.Ans.(i) Vaporise the fuel in homogeneous air fuel mixture.

(ii) To keep small amount of fuel in the serve chamber.(iii) To supply accurate mixture of fuel and air at different load and speed of Vehicle Carburetion. In an engine carburetion means the proper ratio of oxygen with agaseous form of a fossil fuel so that it can combust.

Q. 5. What is the function of vapour return line?Ans. Due to high engine temperature fuel tends to form into vapour in the fuelpump, which lower the boiling point of fuel to avoid this a pipe is connected from fuelpump to fuel tank. When fuel vapour forms they go to fuel tank and get condenser which avoid fuel goinginto the carburettor.

Q. 6. What are the functions of air cleaners?(i) To clean the air which goes into cylinder of engine.(ii) It also acts a silencer for carburetor systems.

(iii) It also acts as flame arrester.Q. 7. What do you mean by stoichiometric mixtures?Ans. When carburettor supply 14.6 parts of air and 1 part of fuel (gasoline) to engine,complete combustion of fuel takes place under ideal conditions. This process is called stoichiometric.

Q. 8. What are the, types of carhurettor?Ans . There are three types of carburettor:(i) Up-drought(ii) Horizontal(iii) Down-drought.

Q. 9. What do you mean by super charging?Ans . It is the process of supplying the air fuel mixture at high pressure.

Q. 10. What is the function of choke value in the carburettor?Ans . The function of choke is to supply the rich mixture to engine so that enginestarts easily and only small amount of air gets into the cylinder or engine.

Q. 11. What do you mean by multi venture system?Ans. Some carburettor have two or more venture in series, the main advantages of this is:(a) It increase the air velocity and also depression in the jet orificial portion, without affecting themaximum air flow capacity of the carburettor at high speed.(b) With this more fuel particles reach the hot spot point of the manifold.

Q. 12. Types of nozzle.Ans . Generally there are two types of nozzles:(a) Hole type(b) Pintle type nozzle.


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Short Answers Type Questions

Q. 13. Sketch any fuel injector and explain its working.Ans . It is known as nozzle, atomises or fuel valve as shown in Fig. 2.1. The mainfunction of injector is to inject the fuel in the cylinder in the vapourised form in theproper quantity.Its mainly consists of nozzle and nozzle holder. This types of construction helps toreplace the nozzle enhances required. It gets fuel from the fuel pump. Spring in the nozzle body keepsthe nozzle value pressed against its seat in the nozzle already till fuel supplied by the fuel pump. Whenfuel spray continues till the clases deleivery from injection pump exhausted and spring pressure againsuddenly closes the nozzle value back on its sead. There is adjusting screw provided on the top of screwto adjust tension of the spring.

Q 14 Explain the functions of a primary and secondary diesel fuel falters Describeany filters of each type?Ans Primary diesel fuel filter It as the wire gauge installed on the suction side of feed pump In this fuelenters through the conical diffuser, the heavy particles accelerate downwards Which can be furtherremoved by drain plug where as fuel goes passes to the outlet of filterSecondary Filters : It is installed after the fuel feed pump. It removes all impuritiesincluding water from fuel. Where as filter fuel passes to ifiter outlet.

Q. 15. Explain various types of modification done in simple carburetor.Ans . There are some points that helps in modifications on simple carburetor.1.Starting problem : For starting their is requirement of rich mixture of fuel but simple carburettorprovides very lean mixture to remove their remedy of providing ticklers which flood the carburettor duringstarting by depressing the float.2. Choke problem : Choke related problem is solved by providing eccentrically choke. When choke work iscompleted force due to pressure on two sides of choke spindle is unequal, which produce turning moment and open the choke.3. Idling difficulty : During idling if engine runs at low speed and throttle value is closed there is lesssupply of fuel to remove this defect a separate idle jet and air bleed hole is provided. So that measuredquantity of fuel and air drawn into idle passage where they form emulsion. Therefore idle speed iscontrolled by adjusting screw.4. Difficulty at high speed: This problem is removed by providing stepped meter rod in the main jet. Whenspeed is increased small diameter rod is in the main jet which increases the supply of fuel.

Long Answers Type Questions

Q. 16. Discuss the classification of petrol injection system.Ans. According to portion of injector we can classify it into there ways.(i) Location of injector.(ii) Timing and duration of fuel injectors.(iii) Control method.(i) Location of injector: Which is further divided into three types:(a) Direct method : This systems is directly placed into the cylinder. It is totally outdated method because


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fuel injector has to work against high pressure of cylinder.(ii) Timing and duration of fuel injector:(a) Continuous type : In this system continuous flow of fuel takes place. It is controlled by fuel pressure.(b) Intermitent: This system works only when there is requirement of fuel. It is also called jerk system.(c) Sequential type: It is most advanced system used recently in vehicle. Inwhich each injector is operated by separate circuit. it supplies exact quantityof fuel at right time.(iii) Control method:

(a) Mechanical : It is old fashioned system in which governors are used to supply fuel in cylinder with thehelp of distributor.(b) Electronic : In this system we used electronic circuit for supplying fuel.

Q. 17. What are the fuel supply system to trouble shootings?Ans. The commonly troubles are as follows:(a) High fuel consumption:(i) There may be leakage in supply system which should be inspected and rectified.(ii) The choked air filter of the engine which should be cleanedproperiy.(iii) Try to run vehicle under constant speed.(iv) The jet of carburettor are worn out which is also the cause of high fuel consumption. It should bereplaced with new jets:(b) Difficult starting:(i) Fuel filter may be clogged which should be cleaned.

(ii) Jet of carburettor may be clogged it should be cleaned.(iii) There may be air leakage in the inlet manifold- which weakens the starting mixture.(c) Poor idling:(i) Correct adjustment of idle screw.(ii) There may be problem of needle sticking which may be rectified by servicing the carburettor and floatchamber.(iii) There may be leakage of oil due to poor gasket.(d) Poor acceleration:(i) This problem is rectified by checking fuel filter which may be clogged.(ii) Fuel line of vehicle may be clogged, which should be cleaned after regular interval of time.(e) Lack of power:(i) Fuel filter may be chocked, which should be cleaned.(ii) Incorrect carburettor setting, which may be rectified.(iii) Over heating of engine:This may be due to weak air-fuel mixture, faulty cooling system and may be due to faulty ignition system.

Q. 18. What are the main circuits of solex carburettor?Ans . This carburettor has been manufactured in India by M/s Carburettor limited, Madras as shown in Fig.2.2.(i) & (ii) This is a draught type carburettor. Its main circuits are:(1) Starting: This is draught type carburettor which supply richer mixture at the starting time and atnormal speed thiner mixture is used. During starting bigger holes of flat disc comes out which is set bydriver on dash board. When engine start smaller hole comes in position.(ii) Idling or low speed operation : In this circuit, air from pilot air jet comes. An idle part is controlled byidling adjusting screw. At this stage value is closed, the engine suction is applied at pilot jet ; that supplypetrol. The mixture of petrol and air comes out at idle passage. As to maintain low speed, slow runningopening are provided on the venture side of throttle value. As throttle value opens suction is applied atlow speed opening, which helps in low speed operation.


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(iii) Normal Running : In this position throttle value is partly open. On the suctionside of petrol jet, mixture of air and petrol is controlled by the throttle value.

Q. 19. What is compensation as applied to carburettors?Ans. When atmospheric pressure is lower at high altitudes carburetor have to produce a richer mixture. Tocompensate this compensator is used which automatically adjust air fuel mixture with the help of aneroidBarometer.


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Chapter 3 : Lubrications and Cooling System

Very Short Answers Type Questions

Q. 1. What are the primary objectives of lubrications?Ans. 1. Primary Objectives:(i) To reduce friction between two moving parts so that there is minimum powerloss.(ii) To minimise less wear and tear of moving parts.2. Secondary objectives:(i) To provide cooling effect.(ii) Act as sealing.(iii) Act as cleaning agent.

Q. 2. What are the basic requirements for lubricants?Ans. There are following major requirement for a good lubricants.(1) Viscosity: It should ensure, hydrodynamic lubrication action should take place.(ii) Chemical stability: It should be chemically stable under different temperature conditions.(iii) Resistance against corrosion : It should be good corrosion resistance agent.(iv) Pour point Pour point of the oil should be less so than lowest temperatureoccurred in the engine.(v) Physical stability: It should be able to stable under different condition of temperature.(vi) Flash point: It should be high to avoid flashing of oil vapours.

Q. 3. What are the various types of lubricants?Ans. (a) Animal oils : These are generally obtained from animal fat. But they are not good lubricants because they are easily

oxidized and become gummy aftersome time of use.(b) Vegetables oils : These are generally obtained from vegetables like seeds, plants and trees etc. It has same problem likeanimal oil but has very goodlubricant proportion.(c) Mineral oil: It is generally derived from the petrochemical and it is most widely used in automobile sector because of

following properties.(i) Greater chemical stability at higher temperature. (ii) Less reactive with water.(iii) More plentiful and cheaper.(d) Synthetic lubricants : These are made from silicon fluids, polyglycol ethers and aliphatic diester.

Q. 4. Why engine lubri is necessity?Ans. Lubrication of engine is very necessary because engine can not run smoothwithout lubrication for few minutes. Because without it piston may suze or there fs more wear and tear of vehicle.

Q. 5. What do you mean by hydrodynamic lubrication?Ans. When two surface are not in physical contact with each other but a thin film of oil is in between two moving contact(surface) the only resistance is the resistance of oil it self this state is called hydrodynamic lubrication.

Q. 6. What do you mean by oil additive?Ans. These are the oil which are added to lubricating oil to reinforce some extra properties other than the natural properties.

Q. 7. Why do we require an anti foaming additive?Ans. Anti foaming agents like polyglycol there act as anti foaming agents which prevent foaming of oil due to enginevibrations.

Q. 8. What is the effect of oil dilution on engine performance?Ans. Oil dilution takes place when leakage of gasoline past the piston into the crankcase or by mixing of water vapour intocrankcase. The effect of oil dilution is that engine should not be raced heavily just after starting of vehicle. Because there isno lubrication at that time.

Q. 9. What are the various sources of oil leakage in the engine?Ans. During combustion when some lubrication goes on the upper side of piston. Oil leaks due to some leakages at variousmoving parts like, crack in crankcase, bearing and seals etc.

Q. 10. What is viscosity index ? What is its importance?Ans. Viscosity Index (VI) is an indication of the change of viscosity of oil withtemperature. The moving of viscosity Index is the indication of change of viscosity of oil with respect to changing condition of temperature.Generally petrochemical lubricants have viscosity index fromlO0 to 110 and byaddition of oil additives it increased to 120 to 130.

Q. 11. What is the significance of SAE viscosity ratings?Ans. The meaning of SAE is society of Automotive Engineers which has classified lubricating oil according to the viscosity.Viscosity rating are OW, 5W, lOW, 20W, 25W, 10, 15, 20, 30, 40, 5Q60, 70, 80, 100, 150, 200, 300.

W indicate for winter use while without winter (w) indicates for lubricating oil having summer use lubrication eg SAEIOW/30.

Q. 12. What are the test performed on lubrications?Ans. Physical Tests

(a) Viscosity test (b) Flash point


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(c) Loss due to evaporation (d) Pour test(e) Specific test.chemical Tests(a) Acid valve test(b) Sponification(c) Moisture and emulsification test.

Q. 13. Why are animal and vegetable oils not suitable for automotive use?Ans. There are following reasons which make the animal and vegetables notsuitable :(i) Because animal oil are easily oxidized and after use they are gummy.(ii) As vegetable oils are also oxidised easily and after use they are not suitable in automobiles.

Q. 14. What is crankcase ventilation?Ans. During combustion of oil in combustion chamber there is possibility of acid formation due to sulphur present in the fuelwhich cause corrosion to engine parts e.g. cylinder walls, piston pins and gear etc.To avoid this flow of air is carried through engine crankcase which causes the combustion products in the form of vapour tovapourise outside. This process is called crankcase ventilation.Method of crankcase ventilations:1. Road draft2. Manifold suction system.

Q. 15. What are wet sump and dry sump lubrication system?Ans. Wet sump is used generally in modern engines it is also called pressure system. In this pump take the oil from wetsump through stainer and delivers it to main oil gallery at pressure of 200 to 400 kPa.Dry sump is generally used in racings vehicles where there is lot off pressure of oil. 1n this two pumps are installed inlubrication line. One reservious is their for proper feeding of oil in oil line. In this oil pressure is maintained at 400-500 kPa.

Q. 16. Name a few materials used for oil filter elements ? What is the material of radiator core.Ans. Wire gauge, felt, paper and plastic impregnated paper are generally used for filter elements.Radiator core are made up of brass material.


Q. 17. What are oil additives and what its functions?Ans. The oil additives are added to the lubricating oil to reinforce some propertieswhich is not the natural properties of fluid or lubricating oil. These additive are added according to the property of lubricants.e.g. Phenols, metal salts of thiophosphoric acid and suiphurized waxes etc. Their important function are as follows:(i) Corrosion Inhilitors : Compounds such as metal salt of thiophasphoric acid and suiphurized waxes act as anti agent in theformation of acid which causecorrosion.(ii) Detergents These additions like polymers act as cleaning agent they break the sludge particles into finely divided particleswhich are easily scavenged throughexhaust port.

(iii) Viscosity index improvers These are the addition which prevent minimisingthe decrease of oil viscosity with increase in temperature.

Q. 18. Name different types of lubrication system.Ans. There are generally five types of lubrications system:(a) Petrol system: Used generally in a stroke engines.(b) Splash system : This is used in early motor-cycle engines.(c) Pressure system : Used in modern cars vehicles.(e) Semi pressure system : Used in Racing cars and vehicles at steep angles.(d) Dry sump systems.

Long Answers Type Questions

Q. 19. What is the objective of using oil cooler? Explain briefly the construction and working of a water type of oil cooler.Ans. The main objective of oil cooler is to dissipate the heat from lubricating oil Fig. 3.1. Oil cooler is a simple heatexchanger oil coolers nd are generally used in heavy vehicles. Where temperature of oil flow raises it cause the decrease inviscosity of the lubricating oil, and the oil film in the bearing might break. To avoid such type of situation heavy engines areprovided with oil coolers.


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Water type cooler is more common because it can be used as reversible cooler. According to the requirement it is used as ininitial stage when oil should not be cooled, rather there is necessary that lubrication oil goes to all lines during starting of engine so that there is less wear and tear of engine, so that complete circulation of oil is take place.Because water is hotter than oil where cooler will initially heat the oil and when higher temperature is reached the reverseprocess is started which will cool the oil so that oil film does not break and to maintain the viscosity of oil.

Q. 20. What are the common troubles occurring in the lubrication system of an automotive engine ? What is theuse of Radiator pressure cap?Ans. Following troubles in the lubricating system are common1. Low oil pressure.(a) If there is low pressure shown by gauge, check it with dipstick and fill the oil in the chamber.

(b) If oil filter is clogged, it should be replaced with new one.(c) If oil is diluted due to constant use, change af ter regular interval of time so that working is not effected.(d) if oil pump may worm out, change its defective parts with new one.(e) If pressure gauge is not working, replace it with new gauge.(f) If spring of relief value is not working and causing the ball to lift at lower pressure than prescribed. The remedy of this isto replace the spring.2. High pressure:(a) If high pressure is shown by gauge because of high viscosity then re-fill new oil of prescribed viscosity.(b) If oil lining are clogged, high pressure valve should be properly cleaned.(c) Oil pressure may be faulty it should be replaced.(d) The other cause of high pressure is that relief value of oil pump is stuck at closing point. It should be properly cleanedand spring setting should be adjusted.3. Excessive oil consumption(a) If oil consumption is more, then check the oil sealing and change it if required.(b) Another cause of more oil consumption is worn out piston rings they should be replaced with new ones.(c) Another cause is worn out value stem. The worn out part is replaced with new one if required.

Radiator pressure cap is used to seal and pressurize the cooling system. Sealing reduces coolant loss from evaporation andpressurizing raises the boiling temperature of the coolant, thereby increasing cooling efficiency.

Q. 21. Explain air cooled engine.Ans. Air-cooled engines rely on the circulation of air directly over hot parts of the engine to cool them.

Internal combustion engines are cooled by a closed circuit carrying liquid coolant through channels in the engine block,where the coolant absorbs heat, to a heat exchanger or radiator where the coolant releases heat into the air. Thus, whilethey are ultimately cooled by air, because of the liquid-coolant circuit they are known as water-cooled. In contrast, heatgenerated by an air-cooled engine is released directly into the air. Typically this is facilitated with metal fins covering theoutside of the cylinders which increase the surface area that air can act on.In all combustion engines, a great percentage of the heat generated (around 44%) escapes through the exhaust, neitherthrough either a liquid cooling system nor through the metal fins of an air-cooled engine (12%). About 8% of the heatenergy finds its way into the oil, which although primarily meant for lubrication, also plays a role in heat dissipation via acooler.

Q. 22. Explain different types of Lubrication system.Ans. Types of Lubricating (Oil) SystemsThe systems used to circulate oil are known as splash, combination splash forcefeed.Splash. The splash system is no longer used in automotive engines. It is widely used in small four-cycle engines for lawnmowers, outboard marine operation, and so on.


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Chapter 4 : Transmission System

Very Short Answers Type Questions

Q. 1. What is the function of transmissions?Ans. There are following main functions of transmission:(i) Provides different torque ratio between the engine and road wheels.(ii) It also helps to reverse the vehicles.

(iii) It also provide neutral position when engine is running and vehicle is in stationary state.Q. 2. What are different types of transmissions?Ans. Generally there are two types of transmission:(i) Manual transmission.(ii) Automatic transmission.

Q. 3. What is transfer base?Ans. Transfer base (gear base) enables the driver to shift two wheel drive to four wheel drive or two driveto low or higher gears as required.

Q 4 Why epicyclic gear is used in automatic gear systemAns By usmg epicyclic gear, different torque speed ratio can be obtained It also compact the size of gearbox

Q. 5. What is torque converter? .Ans . Torque converter is a hydraulic transmission which increases the torque of the vehicle reducing itsspeed. It provides a continuous variation of ratio from low to high.

Q. 6. Define the whirling of shaft?Ans. Vehicles which have large wheel base propeller shaft tends to whirl due to long shaft. To avoidwhirling of shaft a joint is provided in propeller shaft so that length is reduced, supported by intermediatelearning.

Q. 7. What do -you mean by differential?Ans. During turning of vehicle inner wheels speed should be less than outer wheel. Differential helps tomaintain the speed of the vehicles wheel during turning as well as in straight motion.

Q. 8. What is the function of overdrive?Ans. Over drive is used for the step-up gear speed than the speed of engine crankshaft or we can say thatit is used to cause the propeller shaft to turn faster than engine speed.

Q. 9. Show the l ine diagram of gear box.Ans.

Q. 10. What do you mean by full floating?Ans. Full floating housing means that there is no load on the axle shaft. The whole

load of vehicle is on the axle housing.

Q. 11. What is torque tube?Ans . A torque tube is a housing in which propeller shaft encloses. It is attached tothe drive axle housing. Its one portion is connected with gear box and other with the differential box.

Q. 12. What is clutch ? What characteristics an automobile clutch should possess?Ans. It is system or mechanism which helps the engine to conned or disconnectwith rest of the transmissions. -Following properties clutch should have:(1) It should be easily operated.(ii) There should be no slip when engaged.(iii) It should have maximum torque carrying capacity.(iv) It should be noiseless.


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Q. 13. What are the various units of transmission system.Ans . The transmission system consist of following units:(1) Clutch unit.(ii) Transmission unit. -(iii) Drive line unit.(iv) Driving axle unit.

Q. 14. Explain the construction and working of multiple disc clutch.Ans. As the name multiple clutch contains more than one drives to act as a clutch plate. The clutch may

be Wet type with operates in oil and dry clutch whose working is without oil. It is generally used betweenthe engine and gear box.

Construction: All the driven plates are splined to the shaft and there is one driving plate between the twodriven plates. In clutch driven plates are fitted with living or cork segments. These plates can be made of steel, Bronze etc. A pressure plate is attached inside the chamber shell behind all the disc when leaver ispressed. When leaver pressure is released the compressed plate move off causing slip anddisengagement.

Q. 15. What is the difference between constant mesh and synchronomesh transmission?Ans. Constant Mesh gear box: In constant mesh gear box all the gears are in contact with each other.Gears are more on the splined shaft to get different speeds. The required train of gear is made to rotate

the shaft by mean of dog-clutch, which is operated by the shift leaver.Synchromesh transmission : Synchronomesh gear box consist of set of sleeves which slide endwise. Insynchromesh gears there are male and female type of cones which are made of gun metal. The outersleeve fits over the inner sleeve which contain internal teeth to engage with teeth of secondary wheels.This unit slide on the main shaft due to splined on shaft to engage the cone with inner sleeve and engagethe gears with the help of dog clutch.

Q. 16. What are the resistance forces which effect the movement of an automobile?Ans. 1. Air or wind Resistance : This resistance is offered by the wind or air according to the shape of thevehicle, size of body and speed through the air. In practice when speed of vehicle is slow there is lessresistance. When speed of vehicle increases resistance increases very much.2. Gradient resistance:

As shown in fig. 4.2 when vehicle is moving on slant height there is more resistance acting on vehicle. Asweight (w) of vehicle is vertically downward force (R) acting on vehicle tries to push back it downward.This type of additional (R) force is called gradient resistance. Then to overcome equal force is applied toneutralize the effect of (R) gradient force.3. Rolling resistance : It includes the loss to overcome transmission resistance, type pressure, nature of road surfaces, weight of the vehicle.


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Q. 17. Write about the drive shaft. What is the importance of universal joint?Ans It is the shaft by which drive is given to drivmg axle This shaft is also called the propeller shaft whichtransmit the power from engine to differential Vehicle which having long wheel base propeller shaft isdivided into two parts and supported at the middle so that whirlmg of shaft is removed At both end of shaft it is connected with universal jointPropeller shaft contain a slip Joint by arrangement of yoke which having internalteeth, it helps the shaft to extend or squeeze.Universal joint helps to transmit power at uniform rate either rough and toughcondition of roads.

Q. 18. What is the necessity of differential in an automobile ?Ans. It is the mechanism by which outer wheel runs more faster than inner wheelwhile moving on curved road.It consist of number of gear (crown wheel, drive Pinion, star pinion sun gear and pin) when power isprovided by drive pinion which rotates the sun gears. Sun gear are located parallel to ring gear inside thediffeintial chamber and they are face together. When vehicle is moving there is same resistance both thedriving wheels. And offered to the axle shaft more at same speed. But at turn this thing never happens.When vehicle turns to particular side the binding force act on the inner wheel being closer to the pointaround which wheel moves, The sun gear of that side rotate slow as compared to outer wheel whichcauses faster speed of outer wheel.

Q. 19. Explain the automatic transmission system.Ans. Automatic transmission system is the most advanced system in which drives mechanical efforts arereduced very much and different speeds are obtained automatically.

In this system their is no requirement of clutch pressure and changing the gear. Automatic transmissionclutch works automatically. This system is generally also called hydramatic transmission. It containepicyclic gear arrangement, fluid coupling and torque converter. In this planetary gears sets are placed inseries to provide transmission. In this centrifugal governor is fitted in transmission which selects theproper gear speed and throttle position.This system contains hydraulic pistons accomplished with spring control brake bondson the planetary gear sets and clutches within the planetary gear base arrangement.Neutral Drive Low Reverse.In this neutral shows that engine is disconnected with transmission system, Driveshows when vehicle move straight on road, low shows when vehicle moves on hilly roads or middy area

and reverse position shows when vehicle required reversed motion.


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Automatic transmission system have following advantages.1. It simplified driving control.2. Noiseless gear shifting.3. Smoother running due to hydraulic coupling.4. Longer life than mechanical gears.5. Less fatigue to drives or less stress while driving.6. Without clutch, pedal and complicated lever changing mechanism.

Q. 20. Illustrate the construction and working of single plate clutch?

Ans. The single plate dry plate type of clutch is universally used on cars today, although multiplateclutches are used for racing cars. Construction : Single plate clutch is faced on both sides by friction materials known as lining. Themechanism which is used for withdrawal comprises a self lubricating graphite which is, ring shaped. Thegraphite surface forms the actual thrust face taking the withdrawn leading and considerable upto -wearingdepth. The disc is flexible and is not rated directly to its splined. But it also fitted at the centre with anassembly of coil spring which forms the actual driving medium between plate and hub.The use of this is that when clutch is engaged, the spring have a degree of resistanceas the load passes from the disc to hub.All these mechanism comprises of driven plate, pressure plate, springs and related component are housedin steel cones which is bolted on the periphery of flywheel. The whole assembly is called pressure unit.This can be removed, if their is trouble removing the part.

Working : When pressure is applied on the pressure pad by food pedal as a result of this springs are pressed and pressure plates moves back thorougly causing release of pressure from clutchplate. During this disengagement position, flywheel and pressureplate rotates but clutch plates are in stationary state. When pressure is released by clutch spring comesback to their original position.


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Chapter 5 : Steering Systems


Q. 1. What is steering system ? Which qualities it should have?Ans. It is the system used for directional change of an automobile. It connects rotary motion of steering wheel into angularmoment to turn vehicle into particular direction. This system is connected with front wheels of vehicles. It should havefollowing qualities.(1) Easy to operate.(ii) It should have property of self centering so that vehicle move in straight direction.

Q. 2. What do you mean by caster?Ans. It is the backward lift of king pin and axle at top. It gives direction stability to travel in straight direction with minimumeffort by the driver with the help of steering.

Q 3 What is toe in?Ans. It is the amount by which front wheels are more closer together at the front than the rear wheel in the stationary state.This position is called toe-in.

Q. 4. What is the function of king-pin?Ans. The function of king pin is to help the straight ahead recovery of vehicle, which helps to provide directional stabilityalso. When vehicle turns, king-pin causes body to move-up according to wheels.

Q. 5. State factors of wheel alignment?Ans. 1. Steering Geometry2. Steering linkages.3. Suspension system.

Q. 6. What is the purpose of ball joints in the steering linkage?Ans. The function of ball joints is to compensate the expanded spring for wear or any mismatch. Ball joints also decrease thefriction force.

Q. 7. What is the function of steering gear?Ans. The function of steering gear is to convert rotary motion of steering into to and fro-motion of the steering link. It alsoreduced the fatigue to driver.

Q. 8. Where and rack and penion steering gear are used.Ans. Rack and penion gear are simple, light and responsive in nature. It is generally used in MARUTI 800 car. It is very smallis size than other types of steering mechanism or gears.

Q. 9. What is slip angle?Ans. It is the angle between central plane of the tyre and direction of motion of the vehicle. This angle may be vary from 8to 10 for dry and slippery pavement respectively.

Q. 10. What is power steering and what are its uses?Ans. It is the sysbm in which external energy is used to assist the driver in operating. It generally uses following types of energy sources.(i) Compressed air.(ii) Electrical power.


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(iii) Hydraulic power.Uses: (i) It decreases the driver fatigue.(ii) It also decreases the vibration level in steering system.

Q. 11. What types of factors affect the steering systems?Ans. The following are the factors which affect steering systems.(i) Tyre pressure.(ii) Steering linkage connection.(iii) Condition of king pin and lubricating.(iv) Steering gear ratio and back lash.

Q. 12. What types of linkages are employed in vehicles?Ans . There are following types of linkages:(1) Conventional.(ii) Centre arm steering type.(iii) Parallelogram linkage.

Q. 13. How do you classify the steering gear?Ans. Steering gears are classified as:(1) Worm and wheel(ii) Rack and pinion(iii) Worm and sector(iv) Worm and roller(v) Cam and leaver(vi) Screw and nut.

This mechanism is very simple to other steering mechanism and used mostly invehicles. This system was invented by Lankensperger, a Munich Carriage builder in1817.Ackerman principle say, that line intersecting each king pin and tie rod end would interset near the differential. In thismechanism stub axles are pivoted with the axle beam by means of king pin, front axle is fixed with frame with the help of suspension system. In this mechanism a steering Knuckle arm is joined with stub axles so to turn the wheels is requireddirection when steering action is done by driver.

Q. 14. Explain the power steering system.Ans. In this system outer assistance is provided to assist the driver while steeringwith the help of hydraulic system to turn the vehicle.In modern cars this system is generally applied. The power system is designed to become operative when the more than iONof energy is required. This system is mostly used on heavy trucks or containers. In power steering system oils of viscosityrating SAE 5W or SAE lOW are used according to environment conditions.The principle of all power steering system is same when driver steer the wheel itactuate the valve and from valve hydraulic oil goes to the side of the chamber cylinder are the. This processes decrease thefatigue level of the driver and also ease the driving.Generally power steering system are divided into two categories:(i) Internal type

(ii) Linkage typeInternal type power steering is a integral part of the steering gear where as linkage type is an integral part of linkages whichare used for steering system.

Q 15 What do you understand from the terms(i) Oversteer(ii) underteer(iii) Cornering power(iv) Slip angle.(v) Camber.Ans. (i) Oversteer:


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In this case slip angles of the front wheel are less than those of rear wheels, which causes radius to be decreased whileturning. In this vehicle is turned more sharply than rotation given to steering wheel.(ii) Understeer : When the slip angles of front wheel are more than of rear wheels, radius of turn increases. This position iscalled understeer.

(iii) Cornering power : When vehicles turns a centrifugal force acts on the vehicle which produces the thrust on the vehicle.To counteract to that side thrust vehicle wheels take some angle with direction of motion of vehicle. The force produce to thisis called cornering power or force.(iv) Slip angle : When vehicle turns about particular side vehicle wheels move some angle to sustain the side thrust. Theangle moment of wheels to resistance the force is called slip angle.(v) Camber : It is the inward or outward tilt of a wheel from the vertical. A wheel which tilts out at the top has positivecamber and if in then it has negative camber.

Q. 16. What are the various components of steering system?Ans. Steering system consist of various following components.

(i) Steering(ii) Linkages(iii) Steering knuckle.

(i) Steering : This is the mechanism used for changing the direction of vehicle. It consist of steering wheel, steering columnand steering gear.(1) Steering wheel : Which is a circular wheel mounted on the steering shaft which is connected with knuckle joints. it ismostly used to control the vehicle. In modern cars steering wheel is corporated with some controls like horn, indicatorsswitch etc.(ii) Steering shaft: This is the hollow shaft enclosed by casing which transmit the motion from steering wheel to steeringgear.(iii) Steering gear : Steering shaft is connected at lower end with steering gears. Steering gear are of different types.(1) Worm and wheel(ii) worm and sector(iii) Rack and pinion(iv) worm and roller etc.The function of steering gear is to turn the vehicle in required direction.(ii) Linkages : These are the link which are operated by steering gears. In conventional system, steering arms of the wheelare connected with rod called tie rods which are run parallel to axle beam. These steering knuckle arm is projecting out andconnected with pit arm by means of push rod. There are following types of linkages are:(i) conventional type(ii) Centre arm steering type.


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(iii) Parallelogram linkage : In this linkage there is a centre link which is connected with two parallels links which areconnected with the wheels. This arm is operated through drag link. The two arms are further connected with tie rods to theindividual steering arms.3. Steering Knuckle : It is also known as steering spride which is integrated with stub axle of its moved around the kingpin.The force which is conveyed through steering kuncble by means of steering linkage (which is used to turn either vehicle leftor right).

Q. 17. What are the different types of steering problem and what are their remedies?Ans. Steering problems are as follows:1. Wander : This is defect in which vehicle turns slightly to one side and when driver tries to make it straight the vehicleturns slightly to other side.Remedy:(i) Tyre pressure is not equal which may be corrected and checked.(ii) This problem occurs when vehicle is loaded at the rear side.(iii) This problem also occurs due to lack of lubrication in linkages and king(iv) Bearing of steering Knuckle may be tight, which may be corrected.2. Wheel wobble : This type of problem occurred is front wheels or wheels oscillation, this occurs due to unbalanced of wheel assembly.(i) This type of problem occurred when tyres are worn, which should be replaced with new one.(ii) Ball joints are worn out which should be replaced.(iii) Some times camber may be incorrect, which should be replaced.3. Excessive Backlash in steering : This problem occurs when there is slakness in steering system due to worn out ball

joints. Check it and replace if required.

(i) The other cause may be due to loose steering gearbox of the vehicle, which should be tighter.(ii) Check the stub axle bearing if they are worn it may be replaced.(iii) This problem occur if steering gear is not properly fit in gear base of steering.4. Putting one side : Some times vehicle moved or pull in one side and there are following reasons for that(i) The possible cause of this due to worn out tyre or equally filled air pressure is not there in tyres.(ii) Some times brake may be dragging, which can be adjusted.(iii) Misalignment of front wheels, which may be corrected.(iv) If there is suspension system problem, replace it if required or rectify.(v) The problem may occur due to not proper castor angle.5. Hard steering : In this problem driver has to put more effort than required and there are following reasons of this:(i) This problem occurred when there is more castor, it should be tested and corrected.(ii) The problem occurs when type pressure is less than standards.(iii) Proper lubicate the parts or properly fit the parts with each other so that less friction in linkage.6. Poor return ability : This problem occur when wheels are not returned to centre position.(i) If steering shaft is tight, replace its bearing.(ii) Misalignment of steering gear to column.

Adjust the steering gear base if required.


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Chapter 6 : Braking System


Q. 1. What is the purpose of brake shoe adjustor?Ans. The purpose of adjustor is to compensate the wear of brake leather due to regular use of vehicle.

Q. 2. Define servo Brakes?Ans. Mechanism which assist the drivers effort for applying brakes is called servo mechanism. Servo means self energization. Servo Brakes generally used when vehicle load is above 3 tonnes.

Q. 3. What are different mechanism of Brake actuation.Ans. Generally following are the actuation methods:(a) Mechanical brakes(b) Hydraulic brakes(c) Electric brakes(d) Vaccum brakes(e) Air brakes.

Q. 4. What is fading of Brakes?Ans. Fading of brakes means that friction is decreased between brake drum and brake lining due to regular use of brake.

Q. 5. What do you mean by bleeding of Brakes?Ans. Bleeding means to drive out air from braking system. Because if air is entered into braking system their is no actuationof brakes.

Q. 6. What are the basic requirement for braking fluid?

Ans. 1. It should have high boiling temperature.2. Viscosity of braking fluid should be less.3. Brake fluid should not act as corrode agent to component which comes into contact.

Q. 7. Comparison between drum and disk brake.Ans. 1. Drum brakes are heavier than disk brake.2. Less fading of brake lining takes place in disk brake as compared to drum brakes.3. In disk brakes uniform wear of friction lining as compared to drum brakes.4. Disk brakes are more efficient than drum brakes.

Q. 8. What is the locking of wheel during braking?Ans . When the braking force is more than force of adhesion then wheel is stoppedand start slipping on the road. The stopping of wheel by braking is called locking.

Q. 9. Which factors generally effect braking.Ans. 1. Radius of brake drum and diameter of wheel.2. Area of brake lining and amount of pressure applied.3. Coefficient of friction.

Q. 10. Write few advantages of hydraulic system of braking.Ans 1. There is less friction in hydraulic system of braking because there are less

joints as compared to mechanical brakes.2. System is self lubricating.3. In hydraulic system equal pressure is in every circuit.4. System is more flexible than mechanical system.

Q. 11. What is a leading shoe?Ans. A leading shoe is that whose tip is dragged along the drum even when their isno brake force. Due to this reason leading shoe fade more than trailing shoe.

Q. 12. What is the function of brake value?Ans. Function of the brake value is to control the intensity of the braking system inair brakes.It is operated by either foot treadle or by push rods linkage.

Q. 13. What do you understand by brake chamber?Ans. It is a chamber installed on each wheel to connect pressure energy of compressed air into useful mechanical energy forproper application of brakes.


Q. 14. What are the trouble shooting in brake system?Ans. 1. Loss of efficiency in braking:(a) Brake lining does not work properly if oil is entered into brake drum.(b) Due to defective master cylinder, which need overhauling.(c) If air enters into braking system, braking application does not work properly.(d) Brake lining are fade due to regular use or worn out friction lining.2. Brakes overheating: Overheating of brakes occur while we drive a vehicle ascending down the hill or due to faulty bindingmaterial used for brakes binding.

Q. 15. Write short note on disc brake.


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Ans. Disc brake consist of cast Iron disc bolted on the hole of wheel and it is housed in stationary housing called caliper.The caliper is connected to stationary part of the vehicle, like the stub axle and is cast in two parts, each part have a piston.In disc brake each piston and disc there is friction, pad held in position by retaining pairs, spring plate etc. There are passagefor fluid to enter or leave each housing. This passage is also connected for bleeding when brakes are applied friction pads.

Q.16. What are the basic characteristics of brake fluid?Ans. 1. Oil point: Due to high temperature during the braking applications brakefluid should have high boiling point, to avoid vapour formation. Boilingpoint should be generally around 25O-3OOC.2. Viscosity : Due to variations in weather conditions from very cold to hot it becomes imperative that the viscosity of thebrake fluid should vary little with temperature to keep optimum flow conditions. So viscosity should be such that, flow occurin pipes easily without any temperature variations.3. Lubrications properties : Brake fluid should have good lubrication properties so that proper lubrications of brakingcomponents (e.g. master cylinder) is done.

Long Answer Type Questions

Q. 17. How can you classify the brakes ? Explain in details hydraulic brake system with neat diagram?Ans. Brakes can be classified according to following considering the points:(a) Purpose. (b) Location(c) Construction(d) Method of actuation(e) Enter braking effort.(a) Purpose : Brakes can be applied to following ways to vehicle while in motion or in steady condition, mean during runningcondition if we applied brakes are called service brakes. But if we applied during parking or hold the vehicle in slop way arecalled packing brakes.(b) Location : Brakes can be applied either at transmission or at the wheels. Wheel brakes are good in heat dissipation

because energy wheel has separate brake drum which increases surface area and also quick heat disFipation. In automobileswheel brakes are generally used.(c) Construction : Generally two types of brakes are used. One is drum brakes and another is disk brakes.(d) Method of actuation : Following are the ways of actuation.

(a) Mechanical brakes(b) Hydraulic brakes(c) Vacuum brakes(d) Electric brakes(e) Air brakes.(e) Enter braking effort Some times due to heavy loaded vehicles are provided with outside power for application of brakeswhich are helpful for drivers to apply brakes are called servo brakes or power assisted brakes.Hydraulic brakes : Most of the cars today use hydraulic brake system on all the wheels with additional hand brake to stoprear wheel movement.Main part of hydraulic system is a master cylinder which contains a braking fluid. It is well connected with four wheels bysteels pipes, unions and flexible houses.Take the example of Abassadar car in which both front wheel has separate cylinders. On each brake shoe, whereas in rearwheels. There is only one cylinder which operate both shoes. In hydraulic brake system is so designed that a small pressureof 50 kPa is maintained in all pipes times. So that cups of wheel cylinder are expanded always.This system prevents air entering into wheel cylinders while releasing the brake.

Master cylinder: It is called heart of hydraulic base system. It contains two main chambers, fluid reservoir and another iscompression chamber in which piston operates. Fluid chamber which provides the fluid for braking when we apply the brakeswith foot pedal.


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Fluid chamber compensate the fluid volume in pipeline due to any leakage or any temperature variation. To prevent leakagethere are two rubber seals on both end of the piston in compression chamber. A rubber boot is provided at one end of pushrod to present any dirt entering into cylinder. In brake line there is a fluid check value with rubber cup inside in thecompression chamber, Main purpose of fluid check value is to maintained residual pressure in brake lines even when brakesare released.In primary seal side there are number of holes on the piston head. Two holes are connected to reservoir to the compressionchamber. Size of smaller holes is about 7mm and it is also called compensation part/Byepars second hail is calledrecuperation port! intake. To keep fluid at atmospheric pressure their is a vent in the cap.When push rod is operated with links it actuate the piston and further pressure is directed toward pressure lines which applybrakes on the wheels when brakes pedal is released spring pressure in master cylinder push the piston in extreme position.This pressure of spring some times delay the return fluid from lines into compression chamber again. This condition cutesvacuum in compression chamber but is destroyed immediately by intake port in master cylinder which forces fluid into pistonwhich deflects the rubber cup and enters the compression chamber destroying the vacuum.

Q. 18. What are the problems occurring in Braking system and what are their remedies?Ans.1. Brakes binding :(a) To avoid brakes binding anchor pin should be lubricated at regular interval.(b) Brake shoe retracting spring should be replaced with new one after regular interval.(c) In hydraulic brakes by-pass port should be proper cleaned with compressed air and fresh fluid is filled in master cylinder,it should never be cleanedwith wire drill.(d) A hole on the master cylinder is to be cleaned.(e) Brake shoe of vehicle for particular wheel may be adjusted so that dragging of vehicle is avoided.2. Brake judder: It may take place due to wrong brake adjustment which may be corrected by proper fitting of brake lining

by replacing old loose rivets withnew one. In general conditions whole brake lining is replaced.3. Hand brake Ineffective : This problem occurs when starching of operating cable is not properly adjusted. Thisarrangement comes with nut at one end whichcause switching of wire.4. Vehicle pulling one side:(a) Some time dissimilar lining of brake shoe is fitted with different wheels. This problem is avoided by replacing with similarlining on all wheels.(b) Some times dust enters into the brake drum, this also cause pulling of vehicle into one side. This problem is avoided bycleaning the drum.(c) Some times oil or grease enters the brake drum which puts more load on clean linings. This problem is rectified byreplacing greasy lining with drylining.5. Graffing brakes : When brakes are to sensitive, following types of problem occur due to reasons.(a) Back plate may be loose, which should be tightened.(b) Some time brake lining is greasy due to oil leakage should be replaced.

(c) If brake shoes- are not properly adjusted it should be adjusted after regular interval of time.(d) Some time brake drum have a problem, it should be replaced with new brake drum.


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Chapter 7 : Electric System

Q. 1. What are the basic components of battery ignitors system.Ans. The following are the main components:(i) Battery(ii) Ignition coil(iii) Contact Breaker(iv) Condenser(v) Distributer

(vi) Spark plug.Q. 2. What is the function of an ignition coil?Ans. The basic function of ignition coil is to convert low voltage into higher voltage. Basically it is a transformer. In thissystem 12 volt is coverted into 25000 volts in modern car.

Q. 3. What is the function of contact breaker?Ans. The function of contact breaker is to make or break the primary ignition system.In general four cylinder engine it make or break circuit 8000 times per minute.

Q. 4. What is the function of condenser?Ans. 1. Its main function is to minimize arcing and pitting of contact points of breaker.2. Second function is to intensify the spark.3. It stores energy during circuit breaking and supply energy during making of circuit.

Q. 5. What is magneto and type of magnetos?Ans. Magnetos ignition is that which supplies the current to the primary ending of ignition system.It is of two types :(i) Rotating type armature.(ii) Rotating magnet type.

Q. 6. What do you mean by battery capacity ? What is the requirement of a good spark plug?Ans. Battery capacity is represented by amount of current it delivers. And this currentdepends upon the area of plates in the cell and quantity of electrolyte.Spark plug gap should vary from 0.9 mm to 2.03 mm. The electrodes of spark plug should be made of nickel and chromealloys that resist corrosion. Spark plug threads may be coated with an antiseize compound to make plug removal easier.

Q. 7. What type of tests which can be conducted on the battery for testing:Ans. (i) Specific gravity test(ii) Open voltage test.(iii) High discharge test(iii) Cadmium test.

Q. 8. What is the charging system for battery with line diagram?Ans.

In this energy produced from engine converted into electrical energy. Regulator is used to regulate the flow of the current forcharging the battery.

Q. 9. What is alternator regulator?Ans. The function of alternator regulator is to supply current during charging andallow current flow from battery to alternator with the help of diodes which allow flow inone direction only.

Q. 10. What is the function of starting a motor?Ans. Its function is to take supply from the battery and turn the engine at high speed.Such conductor of engine supply constant mixture of fuel and air to the engine.

Q. 11. What are the components of startor motor on testing which can be conductedon starting system?Ans. (i) Armature(ii) Field coil(iii) Brushes(iv) Brush holder(v) Dolanoid switch.

Q. 12. What is the magnitude of current taken by starting motor?Ans. Generally during starting amount of current drawn for starting engine startor motor takes up app. 500 amp.


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Q. 13. What are the possible reasons when startor motor operates but engine is not cranbed.Ans. There are the following points which causes this problem:(i) Flywheel teeth may be broken, remedy of this is to replace the ring.(ii) There may be misalignment of pinion of gear which should be rectified.(iii) Some time spring in the starting motor may be broken which should be replaced with new one.

Q. 14. What is the function of starting derive?Ans. It is a device which disconnects it the starting motor pinion from the engine flywheel the vehicle at once when enginestarts.

Q. 15. What do you mean by magneto ignition system.Ans. Magneto system is old as compared to battery ignition system. In magnetosystem current supply by magneto to primary coil where as in battery current provides by battery to primary coil orwindings.Generally magneto have two types:(i) Rotating armature(ii) Rotating magnet type(1) Rotating armature

In this rotating armature is fitted between two permanent magnet pole on the armature. Number of turns on primarywinding is few hundred where as on secondary winding it in few thousands of this wire. The contact breaker and condensealso inserted into the primary circuit and they also rotate with armature.(ii) Rotating magnet type:

In this magnets only rotate where as fesi coil is fixed. In this condenser, primary and secondary coils are stationary. In thiscondenser and contact breaker are also fixed.

Q. 16. How servicing of ignition system should be done?Ans. For servicing of ignition system energy component should be checked and replaced, if necessary during the checkingprocedure.l. Check the battery and its leads if there is rusting on battery leads terminal it should be placed in hot water and thentightend properly.

2. Second point is that check the coils circuit also check wiring if there is problem replaced it with new coils.3. Third point is that if contact points are dirty it should be properly cleaned with energy paper and also try to maintainrequired gap.4. Fourth point is to check the ignition timing if is not in Qrder keep it in order.5. The most important point is that to lubricate distributer and its shaft and also lubricate the cam mechanism. -6. If all this problem remains then last point is to check the spark plug of vehicle. Adjust the gap between electrodes andclean it.

Q. 17. What are the tests occurred for testing the battery?Ans. There are following points which are required for battery testing are:(i) Specific gravity test(ii) Open voltage test(iii) High discharge test(1).Specific gravity test : In this a glass tu}e is provided called hydrometer which have a scale to measure the specificgravity of electrolyte. It is provided withrubber bulb at top and samplers at the bottom. If sample reading is not upto the mark then b&tery is not properly charged

or battery cells should be changed.


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(ii) Open volt test: This test is performed with the help of ordinary voltmeter. When battery cell shows 2.1 volt it means thatbattery is fully charged in open condition. If we check the battery of car which is in running condition few time before meansrecently charge than we have to remove the surface charge by simply one the head lights for a minute and take reading afterswitching off the head lights after two minutes.(iii) High discharge test This test is very sevore test it should be done on fully charged battery or at least half charged. If thistst perform more than 15 secords it can also damage battery plates permanently.it is performed with simple voltmeter connected with two resistance coil. This test should be performed only for 510seconds when cell tester test performed nearly 150200, times.

Q. 18. What are the test performed on starting system?Ans. Following are the test performed on starting system:(i) Armature(ii) Field coil(iii) Brushes(iv) Brush holders(v) Solenoid switch.

(i) Armature : Armature winding should be checked with multimeter by checking continuity between each segment. If thereis problem, winding should bereplaced.(ii) Field coil : Field coil is checked by testing continuity with the help of multimeter. (iii) Brushed : Brushes should bechecked usually if they are wear more than it actualsize replaced with new one immediately because this cause interrupt of current.(iv) Brushes holders : Brushes holder should be checked with multimeter and alsocheck the proper insulation between holder and holder frame. If there is problemreplace the particular part.(v) Solenoid switch: Before doing this test first remove the lead curve connecting the switch to starter motor then applybattery voltage between switch terminals.If problem occurs pinion should be attached.

Q. 19. What are the battery ignition system components?Ans. The main components of battery ignition system are:(i) Battery, (ii) Ignition coil (iii) Contact breaker (iv) Condenser (v) Distributer (vi) Spark plug.(1) Battery: It is the main part which supplies the initial current to primary coil for giving current to ignition coil. It also

provide uniform voltage to light system at no running speed of the vehicles. Thus it is a foundation of electrical system of vehicle.(ii) Ignition coil : Ignition coil is basically a transformer which connect low voltage supply into higher voltage for starting theengine. It has two types of coils primaryand secondary. Primary coils have 200-300 turns of thick wire and secondary coil have 1500020000 turns of wires.The core is a made of number of laminations of silicon steel or connected iron wire insulated by varnish from each other.(iii) Contact breaker: The function of contact breaker is to connect or disconnect the primary ignition circuit in a enginehaving 4000 r.p.m. It must make and break the circuit 8000 times in a minute. It may be also called sensitive part of theignition system. The contact breaker is generally placed in the distributor of housing contact breaker point which fitted with

camshaft which break or makes the circuit.

The main component of contact breaker are the lines, heel and contacts.(iv) Condenser: Basically condenser is a storage device which store current for small period of time. Its main function is toreduce arcing and pitting of contact breaker point. It also increase the intensity of spark.Condenser store excess energy during breaking period and at make it generally consist of metallic plates usually of tin foil oraluminum foil.Separated by thin sheets of insulating paper on Mica:


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(v) Distributor Generally whole housing which contains contact breaker, condenser, ignition advance mechanism anddistributor is called distributor. The main function of this is to supply high voltage impulse to each spark plug at requiredfiring order of the engine. There are generally main types of firingorder :4cyliner in line 13 42, 1 2 436cyliner in line 1 53 6 2 48cylindertype1--5486372The whole distribution consist of rotor and cap. The material of these is a bakelite.In the distributor according to cylinder number there are similar contacts in thedistributor.(vi) Spark plug: At last there is a spark plug which is the weakest part of ignition system. It is generally mounted on theabove of cylinder of the engine and it can withstand under very severe condition of temperature during combustion of fuel. Itcan withstand temperature upto 2500C and pressure of nearly 7 MPa in the cylinder.It has generally three main parts.(1) Centre e lectrode(ii) Ground electrode(iii) Insulator electrode

Q 20. Discuss the construction and working of a combined voltage and current regulator. How temperaturecompensation achieved in such a regulator?Ans. In this regulator generally three major parts are cutout relay, current regulatorand voltage regulator

It basically consist of series and shunt winding, both these winding wound on thesingle core. In-this series winding have less number of turns having thick wire are used asCombined voltage and current regulator compared to the secondary winding. One point is connected with field terminal andother end is connected with grounded by a contact part where in shunt winding one end is connected with cut out relay andother end is grounded.Voltage regulator working In voltage regulator when generator producing more or higher voltage then the prescribed limit,the force of shunt and series winding pull down the armature and cause break of contact points. Due to this whole process,voltage drop occur in circuit due to resistance in series in the generator field circuit aria due to this voltage again serieswhich cause making of contact and their by grounding the generator field circuit. All of this processes help to guards thecircuit against high voltage and overcharging of battery.Current regulator working : This regulator is consist of series winding. When regulator is not working contact points areclosed at no load. When load increases on circuit generator voltage is not able to regulate the voltage regulator. At thiscondition current rises and at one stage it breakes the contact point circuit which is sufficient to pull the armature. After this


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resistance increase in generator field circuit which causes down the generator output so that series winding on currentregulator circuit connect. At this stage contact points are again connected and another point is grounded.In this way regulator works. Its operating frequency is near about 200 times per second.

A temperature compensator is basically provided in the shape of bimetallic strip on the armature of voltage regulator. Itoperates with the variation of temperature range when there is high temperature it bends the bimetallic strip and weakensthe circuit and at this stage voltage requirement is less. Temperature compensator basically provide higher charging rate inwinter as compared to summer. It takes care of seasonal temperature variation which affect charging capacity of a battery.

Q. 21. What is a Semiconductor?Ans. Materials through which current can flow are conductors and through which itcant are insulators.But the third kind of material exist which are called semiconductors. They are solidand have no moving parts except electrons.


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Chapter 8 : Maintenance

Q. 1. What types of trouble starting problems?Ans. There are following reasons and remedies:(i) Incorrect carburator adjustmentAdjust it properly(ii) Leakage in values: Replace the valves(iii) Incorrect ignition timing : Correct the timing of ignition(iv) Lean mixture: Adjust the correct mixture

(v) Heat control valve defective or seized : Install the spring properly or replace theheat control valve.(vi) Excessive carbon deposit in engine and silencer remedy of this is to decarbonise

the carbon deposit.

Q. 2. What do you mean by is preventive maintenance?Ans. It is the process which done after weekly or monthly so to avoid major overhaul if such preventive maintenance processses are not implemented.There are following points relating to preventive maintenance(i) Use less viscosity coils in winter season so that starting of engine is made easy.(ii) Remove the flints which may have got embedded in type threads. (iii) During starting of engine first worm the enginebefore driving so that properlubrication of parts is taken place.(iv) Clean the battery terminals with hot water after regular interval of time so thatproper charging of battery takes place.(v) In winter seasons when after long joining remove the battery and place it in warm atmosphere because starting capacityof warm battery is more than colder.

Q. 3. What preventive steps should be taken when vehicle laying up for long time?Ans. There are following points which should be applied:(i) Paint all unpainted parts to avoid corrosion.(ii) Apply chromium protective paste on the chromium plated parts.(iii) Wash, clean and lubricate the vehicle thoroughly.(iv) In radiator, add 1% water soluble anti-corrosion oil in radiator water. Then startthe engine and after proper warming of engine draw out the wLole water so thatradiator system become rust free.(v) Jackup the vehicle so that types are inflated or remove load from tyres.(vi) Spray the rocker arms, values and springs etc. with anti corrorion engine oil SAE

Q. 4. What are the general maintenance tips?Ans. (I) Always use correct quality of lubricanting oil,(ii) Keep the tyres inflated to specified pressure.(iii) Use distilled water for batteries never put ordinary water in charge.

(iv) After regular interval clean the charging points with hot water.(v) During garaging the vehicle for long periods, recharge the battery once amonth.(vi) When vehicle is laying long time on ground completely replace the engineoil, radiator water and fill anti-corrosion oil in radiator as well in fuel tank so that corrosion be avoided.(vii) In case of petrol vehicle clean the spark plug properly and in case of dieselengine, clean the injector nozzle so that proper atmosing should take place.(viii) Decarbonise the cylinder head so that proper living of fuel takes place.(ix) Check water level of the radiator.(x) After regular interval of time properly tight all loose nuts and bolts.

Q. 5. What are the causes and remedies of engine overheating?Ans. There are following reasons of engine over heating.(1) Too less fuel mixture : Clean and adjust the carburator(ii) Leakage of water in cooling system : Repair the leakage of cooling system.(iii) Loose for belt: Adjust the belt it belt is loose replace it new one.(iv) Lack of lubrication :(i) Fill the engine oil in engine upto the level,(ii) Replaced the choke filter element.(iii) Clean the oil pump.(v) Choked silencer: If vehicle silencer is choked clean it so that burnt gases removedeasily(vi) Braker Binding Some times braker lining is touching with brake dram whichalso put load on the engine.Remedy(1) Adjust the braker properly(ii) Lubricate the texts and cable joints.(iii) Clean air vent and compresating part of the master cylinder.(iv) Replace chocked brake lose pipes.

(v) Inferior grade of petrol used which causes detonation, use proper grade of oil.(vi) Incorrect uses of gears:Use gears according to the road conditions in hilly area use first or second gears,

otherwise clutch plates are worn out.


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Q. 6. Write note on Bias and Radial plies and how does a radial ply tyre contributes to saving of fuel.Ans. Bias Plies : Bias plies are criss-cross and these tend to move against each otherand produce heat.Radial Tires: In this plies run parallel to each other. It provide better fuel economybecause radial has less rolling resistance and less engine power is required to roll the tire.

Q. 7. Discuss the factors affecting tyre life.Ans. 1. Improper tyre pressure.2. Tyre thread worn out.3. Tire rotation not done properly.

4. Improper wheel balancing.Q. 8. Explain the working of Telescopic Shock Absorber.Ans. Telescopic Shock Absorber: Telescopic shock absorber is designed absorbshock and prevents continuous bounce every time you accelerate, stop , corner or hit abump. Telescopic shock absorber being an integral part of vehicles suspension works to maximize the ability of the tires toperform.Kinetic energy produced by the suspension system is converted into heat. As the shocks piston is compressed (bump stroke)and extended (rebound stroke), fluid in a telescopic shock absorber is forced to pass through restrictive valves. Thisgenerates hydraulic resistance.A telescopic shock absorber can be compressed and extended into two that is bumpstroke and rebound stroke. Nowadays most of the shocks are configured into telescopic design and are configured intodouble acting, which means hydraulic resistance in both bump and rebound.Benefits of telescopic shock absorberThe advantages of telescopic shock absorbers are:1. Smoother ride2. Good handling3 Cost effective4. Available m flexible rangesoil or gas5. Durable and easy to replace.

Q. 9. Write note on pollution due to vehicle emission and exhaust emission control system.Ans. Automobile emissions control is the study and practice of reducing thepolluting emissions produced by automobiles.Motor vehicles produce many different pollutants. The prin!ipal pollutants of concernthose that have been demonstrated tohave significant effects on human, animal, plant, and environmental health and welfareinclude:1. Hydrocarbons : This class is made up of unburned or partially burned fuel, and is a major contributor to urban smog,aswell as being toxic. They can cause liver damage and even cancer. The regulations regarding hydrocarbons vary according tothe engine regulated, as well as the jurisdiction. In some cases, non-methane hydrocarbons are regulated, while in othercases, total hydrocarbons are regulated. Technology for one application may not be suitable for use in an application thathas to meet a total hydrocarbon standard.2. Carbon monoxide (CO) : A product of incomplete combustion, carbon monoxide reduces the bloods ability to carry oxygenand is dangerous to people with heart disease.3. Nitrogen oxides (NOr) : These are generated when nitrogen in the air reacts with oxygen at the high temperature andpressure inside the engine. NO is a precursor to smog and acid rain.4. Carbon dioxide (C02) CO2 is not a pollutant per Se, but is a greenhouse gas and so plays a role in global warming. Theonly way to reduce CO2 emission is to burn less fuel.5. Particulates : Soot or smoke made up of particles in the micrometre size range:Particulate matter cause respiratory health effects in humans and animals.6. Sulphur oxides (SO) : A general term for oxides of sulphur, which are emittedfrom motor vehicles burning fuel containing a high concentration of sulphur.

Automobile Notes

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