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GOVERNMENT ENGINEERING COLLEGE JAGDALPUR, BASTAR (C.G)-494005 LAB RECORD OF AUTOMOBILE LAB 337761 (37) DEPARTMENT OF MECHANICAL ENGINEERING NAME OF STUDENT SEMESTER BATCH ROLL NO. ACADEMIC SESSION LABARATORY CLASSES - INSTRUCTIONS TO STUDENTS 1. Students must attend the lab classes with ID cards and in the prescribed uniform. 2. Boys-shirts tucked in and wearing closed leather shoes Girls’ students with cut shoes, overcoat, and plait incite the coat. Girls’ students should not wear loose garments. 3. Students must check if the components, instruments and machinery are in working condition before setting up the experiment. 4. Power supply to the experimental set up/ equipment/ machine must be switched on only after the faculty checks and gives approval for doing the experiment. Students must start to the experiment. Students must start doing the experiments only after getting permissions from the faculty. 5. Any damage to any of the equipment/instrument/machine caused due to

carelessness, the cost will be fully recovered from the individual (or) group of students. 6. Students may contact the lab in charge immediately for any unexpected incidents and emergency. 7. The apparatus used for the experiments must be cleaned and returned to the technicians, safely without any damage. 8. Make sure, while leaving the lab after the stipulated time, that all the power connections are switched off. Index Sr. No. Name Of Experiment Date Signature Remark AUTOMOBILE ENGINEERING LAB 7th SEM. MECHANICAL LIST OF EXPERIMENTS SL.NO NAME OE EXPERIMENTS PAGE NO 01 To study of chassis and frame . 02 Study of suspension system 04 03 Study of clutches- single plate, multiplate and centrifugal. 08 04 Study of different gearboxes. 15 05 Study of differential mechanism 20 06 Study of break system 23 07 To study of the steering mechanism. 28 08 Study of the front suspension system independent front suspension (IFS). To study of the lighting system

31 Study of the rear suspension systems independent rear suspension (IRS) system. 41 09 10 -4- 01 36 EXPERIMENT NO-1 OBJECT- To study of chassis and frame construction. CHASSIS THEORYA vehicle arrangement without body is called chassis. The various unit contains only the engine transmission is includes clutch, propeller shaft with universal joints, differential and the rear axle shaft; Running systems consist of brakes, wheels, tyres, frame, suspension and steering system. CONSTRUCTION AND FUNCTION OF THE CHASSISCross bracing are provided in the chassis to withstand the shock, blow, twists and vibration. As per the layout, the engine is mounted on the front part of the frame. Rubber cushioned mounts or pads are used to support the engine on the frame. The clutch is placed, next to the engine, connected to the flywheel. Transmission or gearbox is positioned or attached to the clutch shaft. Then a propeller shaft is laid to connect the gearbox On one end and the final drive on

the other end. These are enclosed in a housing, bolted to the rear axle spring, which is connected to the frame through spring. The entire arrangement mounted and bolted on the chassis frame supported by the front and rear suspension systems. This is positioned over front and rear wheel and tyre assemblies, to avoid or minimize the transmition of shock to the frame. -5- THE CHASSIS INCLUDES THE FOLLOWING COMPONENTS- 1) Frame 2) Front suspension 3) Steering Mechanism 4) Radiator 5) Engine, Clutch, gear box, 6) Propeller shaft 7) Rear Spring 8) Road Wheels 9) Differential, Half shaft, Universal joints 10) Brakes and Braking System 11) Storage Battery 12) Silencer 13) Shock absorber, fuel tank, petrol and hydraulic pipe cables and some means of mounting these components. FRAME THEORYThe word frame is used to denote the main skeleton of the vehicle. In automobile construction, chassis frame forms the basis requirement. It serves as the main foundation and base for alignment for the

chassis. The front end of the frame carries the engine and the rear end carries rear axle housing, the wheels and tyres. The other component on the frame are steering system, fuel tank, battery, brake, shock absorber etc. The frame is provided with cross rods increases the rigidity, withstand shocks and vibration. THE FUNCTION OF THE FRAME 1) To carry the weight of the vehicle and passengers. 2) To withstand the engine and transmission torque. 3) To bear thrust, acceleration and braking torque. 4) To resist the centrifugal forces when cornering. 5) To withstand bending and twist. 6) To provide correct spacing between the different component. 7) To serve as a bed for fuel tank, battery and other mounting units. -6- 8) To bear the suspension system. TYPES OF FRAME: There are two types of frame 1) Conventional Frame 2) Integral or unitized frame CONVENTIONAL FRAME:In the conventional construction, the load on the vehicle are transfer to the suspension by a frame, which is supported

by the wheel axis by the leaf springs. Normally used cross sections are channel section, Tubular or box section. Channel section is good for bending Tubular section resist torsion and box section serves as good resistance to bending and torsions INTEGRAL CONSTRUCTION:In such construction, the frame is totally discarded the different unit are fixed to the body itself. It is therefore known as frameless or integral construction .The body and the frame are welded together and result in a light a but stiff construction. Metal pressing and stiffening members are bolted at suitable places to take up the load of engine, gearbox and suspension units. -7- QUESTIONS FOR VIVA1) What is chassis? 2) What is frame? 3) What is the different between chassis and frame? 4) What is the conventional frame? 5) What is the Integral frame -8- EXPERIMENT NO-2 OBJECTStudy of suspension system. THEORYAll the parts which perform the function of isolating the automobile from the road shocks are

collectively called suspension system. The automobile chassis is supported on the axles. Spring provided this support By this means, the vehicle is isolated from the road shocks. Road shocks may in the from of bounce, pitch roll or sway. FUNCTION OF THE SUSPENSION SYSTEM1) It should cushion the shocks due to road irregularities. A good system should have springiness and effective damping qualities. 2) It should maintain the tyre-road grip under all condition during straight driving and braking and cornering. 3) It should be strong to bear the vehicle and passenger load. 4) It should be able to resist the driving and braking torques. 5) It should be able to resist side ways and roll over in order to provide stability to the vehicle. 6) The suspension system should resist the forces which deflected it from its original steering geometry and rotation of axles in the horizontal plane. -9- NEED OF SUSPENSION SYSTEM1) To safe guard the passengers and goods against road shocks. 2) To

prevent the road shocks from getting transmitted to the vehicle body. 3) To preserved the stability of the vehicles while in motion. 4) To provide proper road hold when driving cornering and breaking. 5) To maintain proper steering geometry. 6) To bear the torque and braking reaction. 7) To provide suitable riding and cushioning properties. CHARACTERISTICS OF A GOOD SUSPENSION SYSTEM 1) The design must be such that the unstrung weight should be as low as possible. 2) It should provided maximum deflection but consistent with the required stability. 3) It should be of minimum weight and should require minimum maintenance. 4) The design of the system should be compatible with other components like chassis frame, tyres, steering, etc. 5) There should be minimum tyre wear and good tyre road grip under all conditions. - 10 - DIFFERINT TYPES OF SUSPENSION SYSTEM 1) 2) 3) 4) The conventional suspension system Independent front or rear suspension system Air suspension system or hydra gas

suspension system Hydro elastic suspension system The conventional suspension systemIn the conventional suspension system two wheels are mounted on either side of a rigid axle. The chassis frame is supported on the axle through springs; these can be either leaf spring or coil springs. Thus when one wheel encounters a bumb, the other wheel moves through the same angular movement as the first. It wheel be seen that both the wheels do not execute parallel up and down motion and hence rotate in different planes. Independent front or rear suspension systemThe independent suspension system can be utilized for both front and the rear wheels. Mostly the design is incorporated in the front wheels Here if one wheels goes down in a ditch the other wheel on the road surface is not affected much. Air suspension system or hydra gas suspension systemIn this system certain quantity of compressed air is filled in a container fitted and operated through hydraulic pressure by a piston. This piston is

connected to arm of suspension system thus makes the piston moves up or down when the wheel encounters any irregularity on the road. Now moving of piston up or down, increase or decrease the pressure on the compressor on the compressed air. Hydro elastic suspension systemHydro elastic suspension system works on compression of fluid with the help of rubber washer or cups. There are four units fitted at four wheels with independent suspension, all the units are hermetically sealed and connected to each other with the help of pipes. - 11 - TYPES OF SUSPENSION SPRING 1) Leaf Spring-Leaf spring are made of long, flat strips of spring steel. Several strips are placed one on the other and held together by means of central bolt and clamps. 2) Coil spring-The coil spring is made of a length of special spring steel, usually round in section, which is round in shape of a coil. It is used in the independent suspension systems. 3) Torsion bar-It is a steel bar which function by twisting. It

possesses the same characteristics as leaf spring. One end of the torsion bar is secured to the frame so that it may not turn. As the wheel moves up and down, the arm swing like a pump handle and the torsion bar twists and untwists. 4) Helper spring-Helper springs are used in the vehicles to provide additional support for heavy loads. These are both leaf as well as coil spring types. 5) Spring Shackles-Shackles are a sort of links by means of which leaf springs are connected with the chassis frame. The shackles provide swinging ability to the leaf springs. 6) Rubber Spring-It can store greater energy per unit weight than the steel. For this reason rubber spring system can made more compact Rubber is more reliable. QUESTIONS FOR VIVA1) 2) 3) 4) 5) 6) 7) What is the objective of the of vehicle suspension? What is the function of the spring? What is the material used for leaf spring? What is the function of spring shackle? What is the function of the helper spring? What is a torsion bar?

State the advantages of a helper spring. * - 12 - EXPERIMENT NO-3 OBJECTStudy of clutches- single plate , multi plate and centrifugal THEORYClutch is a mechanism by means of witch engine is connected or disconnected from the rest of transmission. Clutch enables the rotary motion of one shaft to be transmitted to a second shaft having the same axis, when required. FUNCTION OF CLUTCH1) To engage or disengage the rest of the transmission as required. 2) To transmit the engine power to the rear wheels without shock. 3) To enable the gear to get engaged when the vehicle is in motion. Whenever the load of the body is applied to the engine, the transmission load also will be carried. This will be produce unnecessary damping and vibrating and the engine may get damaged. Therefore, some devices are essential to relive the load on the engine and disconnected the transmission temporarily to adjust the engine to meet the demand. The transmission also must be disconnected, while the engine is

idling or about the stop. For this purpose, the clutch is used in the transmission between the engine and gearbox. The clutch is disengaged shifting and changing gears, and during idling. Thus the clutch is a device used to engaged and disengaged the engine with the rest of the transmission. - 13 - PRINCIPAL OF CLUTCHTake two flywheels with center shaft in it. Keep this part If we revolve one wheel, the second will not move, as they are kept apart. Now, bring the second wheel close to the first wheel and press them together. If we turn one wheel the other will also move. QUALITIES OF GOOD CLUTCHi) ii) iii) iv) v) vi) vii) It should pick up load smoothly without grab or chatter. It should have driven disc of low moment of inertia to permit easy shifting of gear. Damp out vibration of crankshaft, if any. It should require little pedal pressure to operate. It should be easy to operate. It should be easy to reapers and over hall. It should be simple and cheep. TYPES OF CLUTCHES1)

Cone clutchA cone having friction material riveted to its periphery remains pressed in the recess of a flywheel with help of a heavy-duty spring. When the clutch is engaged the torque is transmitted from the engine via the flywheel and the male cone to the splinted gearbox shaft. For disengaging the clutch the male cone is pulled out by means of the - 14 - lever system operated through the clutch pedal thereby separating the contact surfaces. 2) Single plate clutchThis type of clutch is used in car, trucks, and tractors. The principal part of the clutch are driving member attached to engine and tiring with and second part is driven member attached to transmission and turning with it The third group is the operating mechanism which include linkages, spring required to apply and release the pressure which hold the driving and driven member in contact with each other. - 15 - 3) Multiplate clutchMultiplate clutch is used in scooter motorcycles, racing cars and bulldozers. Power

from the engine flywheel is transmitted to clutch through clutch facing fitted on the clutch plate. The amount of power, which can be transmitted through plate depends upon its contact area, the facing area that is in contact with the flywheel and pressure plate. To transmit more horse power, we require bigger flywheel and clutch plate but we do not have so much of space available or there is a shortage of space to cope with this problem, instead of one big clutch plate, two small clutches are used. 4) Diaphragm clutchThe diaphragm is a conical steel disc with its outer periphery located in the pressure plate but pivoted to the cover by fulcrum rings and locating studs. When the clutch pedal is depressed, the release bearing exerts pressure at the center of the diaphragm spring. The outer edge of the diaphragm spring moves away from the flywheel, disengaging - 16 - the pressure plate from the clutch plate. The pedal effort required to disengage the clutch is very little compared

to the conventional clutch. This is because of the fact that little force is required to depress the diaphragm spring when it gets curved. 5) Semi-Centrifugal ClutchFor high-powered engine, the clutch spring pressures required may be considerable and thus the action of disengaging the clutch becomes fatiguing to the driver. To obviate this trouble the help is taken of the centrifugal forces. The clutch spring are designed to transmit the torque at normal speeds. While for higher speed, centrifugal force assist in torque tram mission. Such type of clutch are called semi centrifugal clutches. - 17 - 6) Centrifugal ClutchIn the fully centrifugal type of clutches, the spring are eliminated altogether and only the centrifugal force is used to apply the required pressure for keeping the clutch in engaged position. The advantage of the centrifugal clutch is that no separate clutch pedal is required. The clutch is operated automatically depending upon the engine speed. This means means

that car can be stopped in gear without stalling the engine. - 18 - 7) Fluid Flywheel ClutchFluid flywheels are used as clutches in cars employing automatic transmission. At engine idling speeds, the oil does not experiences sufficient centrifugal forces to move the turbine end hence the vehicle does not move. As the driver depresses the accelerator pedal, oil moves into the turbine and rotates the clutch shaft due to the centrifugal force. Thus the car is set in motion at slow speed However, there is a good amount of slip. The hydraulic oil travels back to the pump after releasing some energy to the turbine. CHARACTERISTICS OF AN AUTOMOBOLE CLUTCHi) ii) iii) iv) v) vi) It should be easily operated. It should require minimum physical effort to disengage. It should not slip when engaged. Its wearing surfaces should have long life. Its operation should be noiseless. It should be easily accessible. QUESTION FOR VIVA1) 2) 3) What is clutch? Which are the different types of clutch?

Illustrate the construction and working of a single plate clutches? - 19 - 4) 5) 6) Describe the cone clutch. Describe the centrifugal clutch. Describe the semi-centrifugal clutch * - 20 - EXPERIMENT NO-4 OBJECTStudy of different gearboxes. THEORY – It is a speed and torque changing devices between the engine and driving wheel. FUNCTION1) It exchanges engine power for greater torque and thus provides a mechanical advantage to drive the vehicle under different conditions. 2) It exchanges forward motion for reveres motion. 3) It provides a neutral position to disallow power flow to the best of power train. NECESSITY OF A GEAR BOX 1) To regulate torque by selecting the appropriate speed range. 2) To regulate vehicle speed at which maximum torque is available. 3) To balance the tractive effort with of the various forces tending to oppose the motion. TYPES OF GEAR BOX 1) Selective typei) Constent mesh gear box ii) Sliding mesh gear box iii) Synchromesh gear box 2) Progressive

type 3) Epicyclical or Planetary type - 21 - CONSTENT MESH GEAR BOXIt is that gear box in which all the gear in constant mesh with each other. They are free to move on the shafts which other. They are free to move on the hafts, which are splined. In order to obtain different speeds, the requisite train of gears is made to rotate the shaft by means of sliding dog clutch, which is operated with the help of gearshift lever. The constant –mesh gearbox obtain its name from the fact that all the counter-shaft gear and main shaft gear are in constant mesh. SLIDING MESH GEARBOXIt is that gearbox in which the gear on the splined main shaft are moved right or left for meshing them appropriate gears on the lay shaft for obtained different speeds. This type of gear sox derives its name from the fact that the gears are meshed by sliding or crashing one on to the other. - 22 - SYNCHROMESH GEARBOXIt is that gearbox in which sliding synchronizing units are provided in place of sliding dog

clutches as in case of constant-mesh gearbox. With the help of synchronizing units, the speed of both the driving and driven shafts is synchronized before they are clutched together through the train of gears. The synchronizing units make gear changing easy and minimize noise. PROGRESSIVE TYPE GEAR BOXIt is used in motorcycles. In this gearbox the gear pass through the intervening speeds while shifting from one speed to another. These gearboxes are a combination of sliding and constant mesh gearbox. - 23 - EPICYCLIC OR PLANETARY TYPE TRANSMISSIONIt is uses no sliding dogs or gears to engage but different gear speeds are obtained by merely tightening brake-bands on the gear drums, which simplify gear changing. In order to obtain different speeds any one of these three units can be held from rotation by means of brake bands. QUEITIONS FOR VIVA 1) What is gearbox? 2) What is the necessity of gearbox? 3) Define the different types of gearboxes. 4) What is the necessity of gearbox? 5)

What is the function of the gearbox? * - 24 - EXPERIMENT NO-5 OBJECTStudy of differential mechanism. THEORYWhen the car is moving on a straight road both the rear wheels will be turning at the same sped. When the car takes a turn and the both the wheels are rotating at same speed, it will be difficult for the return of the wheels to take place and vehicle may get toppled if it is with solid rear axle. So there will be a tendency for the wheels to skid. So in order to avoid the above difficulties some mechanism is needed to reduce the speed of the inner wheels and increase the speed of outré wheels during turning and bring the wheels to rotate at same speed. Such an arrangements which provides the above requirements is known as Differential. - 25 - PRINCIPLEThe figure explains the function of differential. When the shaft is moved in a straight-ahead position, the bevel gears along with the shaft shall revolve at the same speed in the same direction, irrespective of the speed

of the shaft. If as shown in the figure-b, s-2, is held,stationary,then the right side bevel gear will not rotate. In this case if the main shaft is assumed to move forward the pinion rotates about its own axis and the left side bevel gear rotate faster than in the previous case. Because in this case the left side bevel gear receives two different motion due to 1) Forward pulling of the shaft as before. 2) Rotation of the pinion about its own axis, which is in constant mesh with the bevel gear. Suppose the right side bevel is allowed to slip on pinion wheel, and then the left side bevel gear shall rotate at a lower speed than in the previous case. WORKINGWhen the vehicles take a turn, a binding forces acts on the inner wheel In that particular side the sun gear is held to rotates slowly with respect to the movement of the cage. This results in the star pinion rotating the outer side sun gear with a loss in the inner wheel speed and gain on the outer wheel speed. So the outer wheel

moves faster Due to the result of differential action, if the right wheels rotates at N rpm, the left wheels rotates in the opposite direction with n rpm.This arrangement makes the resultant speed of the left wheels as (N+n) rpm. But the torque transmitted is equal to both the rear wheels - 26 - TYPES1) Conventional 2) Non slip 3) Double reduction type CONVENTIONAL TYPE DIFFERENTIALA differential consist of a casing in which the differential gears are assembled. The crown wheel or ring gear is attached to the rear axle shaft on bearings. The drive pinion is attached to the propeller shaft; two gears are attached to the end of the rear axle. Star pinion mesh with the sun gears Two or four star pinions are provided. The star pinion are carried on pins The pinions are free to rotate above their axes. The pin is held between the two parts of the case. The sun gears are rosined parallel to the ring gear inside the differential case. The assembly is supported on taper rolled bearings.

The entire arrangement may be made to rotate as a single unit, so that the axle shafts rotate at the same speed, when the vehicle is moving straight. NON SLIP DIFFERENTIAL OR SLIP DIFFERENTIALThe conventional differential delivers an equal amount of torque to both the wheels. Suppose the vehicle is moving on a muddy, or slippery road, or if only one wheel is on slippery surface, any one or both the wheels may becomes stationary for a while. To avoid this trouble non-slip differential are provided. It is similar to the conventional type but it is provided with two sets of multiplate clutch. The clutches are positioned between the sun gears and the case; the frictional resistance between the clutch and sun gears limits it. This increased frictional resistance increases the driving torque At this stage the clutch plates lock the un gears and the axle along with the differential case. At this movement the speed differential in between half shaft are reduced and wheel spinning or slipping

is prevented DOUBLE REDUCTION TYPE DIFFERENTIALThis mechanism provides one more gear reduction between the engine and the road wheels. The drive pinion is positioned to mesh with the ring gear - 27 - mounted on a parallel shaft. The ring gear consists of a reduction gear set, driving a driver set of gears attached to the differential case. This helps to obtain gear reduction between the two gear reduction sets. QUESTION FOR VIVA1) What is a differential mechanism? 2) What is the function of a differential mechanism? 4) What is the principal of differential mechanism? 5) What is the working of the differential mechanism? 6) Define the types of the differential mechanism * - 28 - - 29 - EXPERIMENT NO-6 OBJECTStudy of brake system. THEORYbrake is the mechanism in motor vehicles for slowing down and stopping. Braking is the method of slowing down and bringing down the vehicle to rest at the shortest possible distances. While operating the braking system, kinetic energy of the

moving vehicle is converted into heat and gets dissipated. Thus the function of brake is to slow down, to stop to hold the vehicle and also to help in the energy conversion and dissipation. PRINCIPLEA moving vehicle possesses kinetic energy, which is converted into heat energy on the application on the application of brakes. This heat is transferred to the surrounding air. In this simplest form, a break comprises a stationary brake shoe with a friction lining on it and a break drum. The road wheel is fixed to the rotating brake drum. The driver applies force on the road pedal that gets amplified and pushes the stationary shoe to make contact with the brake drum and stop its rotation due to frictional resistance. NEED OF BREAKS1) 2) 3) 4) To stop the vehicle. To control speed, when and where required quickly and efficiency. To control the vehicle while descending along a slope. To keep the vehicle in the required place after bringing it to rest even when the operator in not present.

BREAKING REQUIREMENTS1) It should develop maximum possible retarding force irrespective of road conditions and quality. 2) The retardation produced should be uniform throughout its application. - 30 - 3) 4) 5) 6) 7) 8) The response time should be as minimum as possible. Must be reliable and should not be affected by water, heat, or dust It should not be affected by the wear of its components. Little maintenance, adjustment and care are need. Should be minimum weight. Noise and vibration are to be minimum. TYPES OF BRAKE1) By applicationi) Feed brake or service brake. ii) Hand brake or parking brake. 2) By method of poweri) Mechanical ii) Hydraulic iii) Vacuum iv) Electrical v) Air 3) By method of operationi) Manual ii) Servo system iii) Power operation 4) By constructioni) Drum ii) Disc DRUM BRAKESThese may be (i) internal expanding and (ii) external expanding. Internal expanding brakes have brake shoes contained within the brake drums and expand outwards and expand outward to

make contact with the rotating brake drum, where’s external expanding breaks contact to make contact with rotating drum. Brake drums are made of nickel-iron casting; this metal gives optimum rate of heat transfer and provides good anti-wear qualities. Scooter and motorcycle brake drums are made of cast aluminums with a bonded cast iron liner. These run cooler and transfer heat fast and have ribs on its outer surface to provide the necessary strength. The brake - 31 - back plate is fixed to the stationary axle casing whereas the drum is fixed to the rotating axle and road wheel. There retracting spring spring brings back the shoes to their original position when the brake pedal is released. DISC BRAKESIt is made of high-grade of gray cast iron having pearl tic structure to give better wear resistance property. The disc which rotates with the car wheel is efficiency cooled as most of its area lies exposed Vent led disc have two disc linked by internal ribbing instead of one thick

disc. When the driver applies pressure on the break pedal, hydraulic pressure pushes the piston out from their housing. The piston, in turn press the brake pads against the moving disc faces, causing friction and hence slowing it down. Hydraulic pressure is equally applied by the hydraulic fluid to the floating piston on either side. When the driver takes his foot of the brake pedal, hydraulic pressure on the friction pads is released, the piston move inwards and brake their contact with the disc. - 32 - MECHANICAL BRAKESMechanical brakes have been outdated in cars but are mostly used as parking brakes. Scooters, motors, motorcycles and mopeds use such type of brake The leading shoe is the first shoe after the cam in the direction of rotation. The friction between the shoe and the drum pushes the tip of the leading shoe harder in contact with the drum and pushes it off at its toe, where the trailing shoe tips is throw away off the brake drum, as the drum rotates against it. The

braking effort by the leading shoe is four times that of the trailing shoe and hence it wears faster. - 33 - HYDRAULIC BRAKESThe hydraulic brakes give higher efficiency than other system. It applies equal pressure on all the four wheels. It suit vehicle having independent suspension system. A hydraulic fluid transmits pressure equally to all brakes shoes based on PASCAL’s law which states that when any part of a confined fluid is subjected to pressure, the pressure is transmitted equally and undiminished to every portion of the inner surface of that container. AIR BRAKEIn this system, the operation of the cam in the wheel cylinder is by means of air pressure. The air pressure is obtained by air-compressor driven by the engine. There are separate brake chambers for separate cams The brake chamber is connected with the air void. A brake valve, operated by foot pedal, Controls the pressure that affects the brake chamber. When the foot pedal is pressed, air pressure acts up on the

diaphragm of the brake chamber. When the brake pedal is released, the brake valve is closed which releases the pressure in the brake chamber QUESTION FOR VIVA1) 2) 3) 4) What is breaking system? What is the function of the braking system? What is the function of the braking system/ What is the needs of brake? - 34 - 5) What is the requirement of brake? 6) Define drum brake, disc brake, and mechanical brake. 7) Define hydraulic brake, air brake * - 35 - EXPERIMENT NO-7 OBJECTTo study of the steering mechanism. THEORYIt is the system, which provides directional change in the performance of an automobile. This system converts rotary movement of the steering wheel into angular tyre of the front wheels. It multiplies driver’s efforts by mechanical advantages; enable him to turn the wheels easily. FUNCTIONS1) 2) 3) 4) To turn the vehicle at the wanted of the driver. To control the wear and tear of tyres. To multiply the effort of the driver for easy operation. To convert the

rotary motion of the steering wheel into angular displacements of the front wheels. 5) To achieve the self-righting effect. 6) To absorb road shocks and to prevent them from reaching the driver. - 36 - REQUIRMENTS1) The front wheels should roll without lateral skid while negotiating curves. 2) There should be proper proportion between the angles turned by the front wheels. 3) The tyre must have good elasticity so that on turns, these may follow an arc of greater radius than the stiff tyres. 4) The angular oscillations of the wheels must be minimum. 5) The system must be irreversible to a certain degree so that minimum front wheel shocks are transmitted to the driver’s hands. TYPESThere are two types of steering mechanism1) Davis steering system. 2) Ackerman steering system. COMPONENTS OF STEERING SYSTEM1) Steering 2) Steering linkages 3) Steering knuckle. SteeringIt is the mechanism, which changes the direction of rotation of the steering shaft at right and provides leverage or

mechanical advantage between the steering and the steering linkage. It is composed of the following componentsi) Steering wheels ii) Steering Column iii) Steering gear. Steering linkageThese linkages connected steering gear knuckle arms of the front wheels and drop arm at the steering gear. They carry backward and forward swinging - 37 - effect of drop arm to the steering knuckles. The steering linkages as employed in different vehicle are of the following typesi) Conventional ii) Center arm steering types iii) Parallelogram linkage. Steering knuckleIt is the arm, which is integrated with the stub axle of its movement around the pivot, which is known as kingpin. The steering effort is conveyed to the steering knuckle by means of steering linkage for Turing the road wheels to the right or left direction. Each stub axle has its own steering knuckle arm, which is connected with each other through tie rods. FACTOR AFFECTING STEERING1) Steering gear ratio-It provides mechanical

advantage for the driver to guide the vehicle by exerting only a small amount of physical effort at the steering wheel 2) Steering linkage connection-They must provide free movement of the linkage to transmit driver’s effort at the steering wheel to the knuckle. 3) Tyre pressure-It should be as per specification, 4) Play in wheel bearings-The wheel bearing should be properly adjusted. Less play shall be result in hard steering and more play shall effect wheel alignment and leads to wheel wander. 5) Wheel alignment-This relates to the relative position of the wheels for obtaining a true and free rolling movement over the road. QUESTIONS FOR VIVA1) What is steering system? 2) What is the function of the steering system? 3) What is the requirement of the steering system? 4) Define the type of steering system. 5) Define the components of steering system. 6) Which fasters are affecting the steering system? * - 38 - EXPERIMENT NO- 8 OBJECTStudy of the front suspension system .

independent front suspension (IFS). THEORYThe independent front suspension is almost universally adopted on front axle (wheels) of all the vehicles now. It is due to its simple construction and the advantages claimed in the preceding article. Different types of independent front suspension system are employed on various automobiles. These are – 1. Divided axle (or swinging half axle) type 2. Wishbone ( or unequal links ) type as used on Tata: Sierra, sumo, Estate. 3. Mac Pherson strut type- as used on Maruti 800 Deluxe, Fiat Uno, Zen, Cielo. 4. Vertical Slide Type- as used on Morgan 5. Training arm (or link) type- as used on Kinetic Marvel 6. Equal links type- as used on racing cars Now we shall describe each of them in detail. WISHBONE TYPE FRONT SUSPENSIONA wishbone type IFS is shown in fig 11.1 The left half of this figure is shown in its real from of construction while the right half is depicted in linkage from. It consists of the following main points- - 39 - Fig-11.1

Arrangement of wishbone type independent front suspension (IFS) system i) Smaller upper wishbone and longer lower wishbone. ii) Connecting arm to connected upper and lower wishbone with the king-pin. iii) Coiled spring enclosing a shock absorber. iv) Frame cross-member on which are pivoted the upper and lower wishbones. The spring and shock absorber are supported between the lower wishbone and underside of the frame. The shape of both the wishbone arms is of V-type, which resembles the shape of chicken’s wishbone. That is why the construction is named as ‘wishbone type’. During motion when the wheel encounters a bump, the weight of the vehicle is transferred to the coil spring through the connecting arm, upper wishbone and the cross arm. This is then transmitted to lower wishbone which pushes-up the shock absorber. Consequently, it damps-down the vibration in the manner stated earlier. The wishbone arms are shaped in a specialized Vprofile. It is done so as to keep the wheels in

correct positions, to resist forces produced due to acceleration, braking and cornering. another signification feature of this construction is S its unequal lower and upper arms. The upper arm is made shorter in length than the lower arm It is done so as• To maintain a non-varying wheel track (width between two wheels), • To minimize tyre scrubbing its wear. - 40 - However, the reoriented configuration of the linkage as shown dotted, and the camber angle of the wheel are changed a little. This is an unwanted result and may be treated as disadvantage of wishbone type suspension. MACPHERSON STRUT TYPE FRONT SUSPENSIONThe up and down movement of wheels resulting into a change in the wheel cambers a big drawback of wishbone type suspension. Moreover, double wishbone arms make this system a heavier one. These shortcoming have been eliminated in the McPherson strut type IFS. Its simplified construction’s is shown in fig 11.2 It consists of a lower wishbone only whereas the upper

wishbone has been replaced by a strut ( a member under compression). On one end the lower wishbone is hinged to a channel shaped connector. This connector is centrally attached to the stub axle and also to the strut on its upper side. The strut ends are so shaped that they hold on the shock absorber and the coiled spring enclosing it. Fig.112 Arrangement of MacPherson strut type IFS - 41 - Since the space occupied by this arrangement is less (in the front), therefore it is more favored suspension system on the front wheel driven vehicles. It also allows more space for the engine The road safety and riding comforts are due to better wheel alignment (non-changing camber). The unsprung weights are also reduced due to a lighter construction. VERTICAL SLIDE TYPE FRONT SUSPENSIONWhen the wheels rise up and fall-down on the road surface, the distance between wheels should not vary that is a constant wheel track must be maintained. If it is not so, a ‘scuffing’ action occurs that

results in quicker wear of tyres. Although it is almost impossible to eliminate the ‘side-scrub’ entirely but the wishbone system nearly does so. However, perfection in this regard may be obtained by employing a vertical slide arrangement. Fig11.3 shows a simplified construction of this type In it, the stub axle slides vertically on a long pin which carriers the main (coiled) spring as well as a small coiled (rebound) spring. The up and down motion of the road wheel due to a bump causes up and down sliding of the swivel block which either compresses the main spring or stretches it. The rebound spring is used to exert rebounding pressure. The main spring encloses the shock absorber, Fig.113 Arrangement of a vertical slide type IFS system - 42 - and is connected to an arrangement of upper, lower and diagonal rods/arms. These rods are attached on the frame of the vehicle. TRAILING ARM TYPE FRONT SUSPENSIONSimplified version of a trailing arm IFS is shown in fig11.4 In this

arrangement, a coiled spring is used in horizontal position instead of vertical position. Its one end is attached to the frame side member while the other is fixed on one end of the trailing arm. The trailing arm, at its other end is connected to front wheel shaft which carriers a wheel hub. Fig.114 Trailing arm type independent front suspension When a vertical moves on a road bump, the wheels start moving up and down whose motion is transferred to the spring via trailing arm. Consequently the coiled spring winds or unwinds, and vibration is produced in it. These vibrations are forcibly damped by means of a multiple type shock absorber. The system incorporates another arm to sustain braking torque. In some designs, a torsion bar is used instead of coiled spring * - 43 - EXPERIMENT NO-9 OBJECTTo study of the lighting system. THEORYLighting system is responsible to glow various lighting in an automobile. The main lights are as underi) Head lights, ii) Tail and stop lights, iii)

Side and parking lights, iv) Dash lights, v) Cab and body lights. The lighting system contains the following main components, which are connected through electrical wiring to complete the circuiti) Various lamps or lights, ii) Switches, iii) Fuses and circuits breakers, iv) Junction box. LAMPAn electric lamp consists of a cover, reflector, bulb, holder and lens. 1) Bulbs- Small incandescent bulbs are used in most lamps. The bulbs are filled with a gas and are designed to operate on a low voltage. The - 44 - bulb s contains single or double filaments and or two contacts at the base accordingly. 2) Reflectors-The reflectors are employed in the lamps to collect the rays and distribute them outward in the form of a beam. 3) Lens-The main light lens contains flutes and prism built into them, which help in bending and distributing the light emitted by the reflector into the desired beam pattern to cover the road. HEAD LAMPS OR LIGHTSThe modern head lights are fitted with sealed beam

which consist of a permanently sealed glass lens and reflector contains two filaments-upper and lower. SIDE OR PARKING LIGHTSThese are small lamps which are fitted by the side of headlights. These lights are generally used at the time of parking that is why these are known as parking lights. For parking a vehicle during dark, it is necessary TAIL AND STOP LIGHTSThese lights are fitted at the tail of the vehicle and provide red signal for the vehicles running behind. Taillights are put on and off by means of a switch provided at the dashboard and are kept glowing all the way while the vehicle is operating during dark. DASH LIGHTSElectrical lamps fitted at the dashboard and providing lights for visibility of different gauges and switches etc. are known as dash lights - 45 - CAB AND BODY LIGHTSThese are the lights which are fitted inside the cab and body for the convenience of the driver and passengers. SWITCHESA switch opens and closes an electrical circuit. Various important

switches used in the lighting system of an automobile are as under1) Main light switch-Mostly it is either pull-push or rotary type switch. 2) Dipper switch-It is a rotary disc and plunger or rotary contact and push-pull type switch by means of which dimming of head lights is done. 3) Stop light switch- When operated direct by the brake pedal, it is an off and on type mechanically operated switch. FUSES AND CIRCUIT BREAKERSFused used in automobiles consist of a glass-enclosed strip of alloy metal having a low melting points. When a short circuits or overload occurs in a circuits, the fuse burns out and opens the circuits so that no further damage may occur. JUNCTION BOXAs its name indicates it is a box, which serves as junction for the various electrical lines. Usually fuses are provided in the junction box to avoid the damaging effects of over-load and short circuits. QUESTION FOR VIVA1) 2) 3) 4) 5) 6) 7) What is lighting system? What is the use of reflectors? What is a use of lens?

What is the parking light? What is the tail and stop lights? What is dash lights? What is junction box? - 46 - EXPERIMENT NO- 10 OBJECTStudy of the rear suspension systems independent rear suspension (IRS) system. THEORYThe IRS system on automobiles was adopted much later than the IFS system due to its exorbitant cost and inconvenient designs in early days. However, the improvements in its design made it popular and it gradually replaced the rigid axle rear suspension. This system has numerous advantages in that it ensures the two rear wheels being parallel to each other and perpendicular to the road surface. An IRS system is a rule than a choice for rear engine vehicles. There are a variety of ways in which the rear wheels can be independently suspended. These methods have a common feature in that the differential unit is mounted directly over the vehicle’s structure in that the differential unit is mounted directly over the vehicle’s structure so that the unsprung weight is

reduced. Several IRS system are being adopted on automobiles, the main among them are• Swing-axle type-as used on Hero Winner • De Dion rear axle type- as used on Caterham Super 7 racing car • Articulated De Dion type with slip joint • Trailing link (or arm) type- as used on Bajaj KB 125 RTZ, Maruti Zen, Peugot 309 • Wishbone arms type – as used on Contessa Classic, Premier Diesel • Mac pherson type- as used on Toyota Corona car, Maruti 1000, Esteem, Lancia. • Multi-link systems- as used on Mitsubishi Lancer car, Ceilo. SWING –AXLE TYPE IRS SYSTEMThis is the earliest of IRS, which has undergone many changes in its design. An improved design used on Jaguar car is shown in fig121 in - 47 - simplified form. It mainly consists of an upper link (or cordon shaft) and a lower arm. The lower arm is hinged at its both ends: one to the differential casing and the other to the hub-carrier. The hub- carrier also supports the stub axle. Fig.121 Arrangement of swing-axle type

IRS system The cordon shaft is of fixed length and transmits power to the stuff axle. It has Hooked type universal joints at both of its ends The springing is obtained by means of a coiled spring, which houses a shock absorber inside it. Another pivoted link AB connects the lower arm with the car structure to maintain fore and aft location of the wheel. DE DION REAR AXLEThe De Dion rear axle design of IRS is a earlier method and was used on racing cars. Fig 122 - 48 - Fig-12.2 The De Dion rear axle It consists of an axle tube located across the car and the axle tube ends are rigidly attached to the hubs. The purpose of such attachment is to maintain the wheels parallel at constant wheel track and perpendicular to the road. The tube can move up and down but is constraint in side to movement It is done by means of a vertical slide and a linkage in which a ball slides within a vertical guide. The power is transferred from differential unit to the hubs by means of cordon shafts.

These shafts are attached on the wheel hubs and the inboard brakes by means of universal joints. ARTICULATED DE DION TYPE IRS SYSTEMThe De Dion rear axle in above enables a big reduction in unsprung weight and obviates wheel lift due to torque reaction, but it does not provide independent suspension to wheels. To obtain an almost independent suspension, the main tube is divided near its center and is articulated by joining the two ends through a slip a joint. Fig123 - 49 - Fig12.3Arrangement of an articulated De Dion type IRS system employing a slip joint. The rear axle casings are provided with universal joints near their ends. The universal joints assist in keeping the wheels vertical while the sliding joint helps in maintaining a near constant wheel track. The slip joint accommodates the changes in length caused due to up and down movement of the wheels. TRAILING LINK TYPE IRS SYSTEMThis system incorporates two trailing links (fig. 124) one at rear wheels. The links hold-on

the wheels firmly at their ends The shock absorber enclosed concentrically within the helicaly coiled springs is mounted on these links. These cordon shaft are provided with universal joints in usual manner. - 50 - Fig.124 Arrangement of trailing link type IRS system * - 51 -