Evolution of the Hyundai Santro Xing Final

B V Bhoomaraddi College of Engineering and Technology Vidyanagar Hubli 2011-2012

Department of Automobile EngineeringA Report On

Vehicle Body Engineering Of Santro Xing

By:

Basanagouda Patil (2BV08AU005) Jotiba Gondakar (2BV08AU017) Shravan Jodalli (2BV08AU047)

Shreeshial Biradar (2BV08AU048)

Guide : Prof. T. Veeramanhantesh Swamy

Evolution of the Hyundai santro XingThe Hyundai Santro Xing (also known as Atoz, Amica and Santro Atos) is a city car produced by Hyundai. The original Atos was introduced in 1997. In 1999, it was joined by the less controversially styled Atos Prime. It uses the G4HC Epsilon straight-4 engine. The second generation Atos Prime was launched in 2004. It comes with a 1086 cc G4HG engine. The first Atos was introduced in 1997. It is fitted with a 999cc engine and has a top speed of 90 mph (145 km/h). It was succeeded by a facelift version by 2000. A facelift version came in 2000. It was discontinued in Europe in 2007, in favor of the Indian assembled i10 and in other markets in 2011. OTHER NAMES The Atos Prime is marketed as the:

Hyundai Amica in the United Kingdom Hyundai Santro Xing in India Atos by Dodge in Mexico Kia Visto in Indonesia and South Korea Inokom Atos in Malaysia Hyundai Santro in Pakistan

The original Atos was sold under the Hyundai brand but rebadged as the Atoz (or "AtoZ") in some markets, including the United Kingdom. The Hyundai Santro is a rebadged version of the city car Hyundai Atos sold in some Asian markets.Hyundai entered the Indian market in 1997 with the Atos, marketed under the name Santro. Produced at Hyundai's factory in Chennai, its primary competitor at the time was the popular Maruti Suzuki Zen. The distinctive styling of the first generation had mixed reviews, but the car was a success primarily due to its features and price.In the years since, the Indian version has undergone a number of upgrades in styling and technology to respond to consumer preferences. In 2003, the first generation was replaced with the second generation Atos Prime, marketed in India as the Santro Xing, which continued to enjoy sales success. The car is also exported from India in large volumes to the Asia and Oceania region.Figures as listed for the 2000-2003, 5 door, 1.0i model with GSi trim as sold in the UK (as the Amica), with standard options.

Engine:eRLX means 'active intelligence' technology engine You encounter varying driving conditions everyday. Always demanding more from your cars engine. In terms of power efficiency, reliability and long life. Just like each driver is unique, so is each engine. The 'active intelligence' technology empowers the engine to think and operate at its best under usage condition, delivering maximum power and mileage. It does the job of opening and closing the valves with effortless ease,delivering more power while reducing the engine work load. Because of this the engine heath up less and

gets more life. Add to this the thin section low-friction piston rings reduce mechanical load, plus wear and tear. mileage from the engine. During rapid acceleration. When more power is required, injectors are pulsed in groups of two at a time. At cruise, injectors sequentially deliver fuel to the cylinders as per the firing order,thereby delivering the best of mileage. It determines the perfect time to ignite the fuel and air mixture under any condition. Instead of fixed ignition curves in normal programmed ELUs, the klil Read the quality of fuel and your mind, changing the ignition timing accordingly to deliver perfect combustion. Resulting is superb mileage, power and ultra low emissions .

Aerodynamic StylingThe much-improved low drag co-efficient of the wind tunnel developed shape of the Santro Xing ensures maximum fuel economy while the specially designed large radiator grille and massive bumper air dam maximize airflow into the radiator, keeping the engine cool and at peak operating efficiency.

Great Ride QualityThe Santro Xing features the world class McPherson Strut Suspension with a stabilizer bar in the front and a torsion beam axle with 3-link offset coil springs and hydraulic dampers in the rear. This helps to iron out the pot-holed Indian roads with a smile. Not only that, the wider tyres give you surefootedness even on slippery surfaces. Ventilated Disk Brakes The Santro Xing comes equipped with larger 'Ventilated' front disc brakes. These ventilated discs, with in-built air vents along the circumference, dissipate the heat generated by braking, much faster than the conventional solid discs and enhances the life of brake pads. The ventilated discs also cool down much faster, providing solid and dependable brake performance even under the most severe traffic conditions.

Safety:Crumple zones, child-locks, and high torsion impact bars are the standard safety features that are available in all the variants of Hyundai Santro Xing. Additional protection against side impact is facilitated by the pair of ultra-high strength steel members that are fitted into the doors of the automobile. Santro Xing had been made to undergo rigorous crash tests, so as to ensure uncompromised safety for its occupants.

Crumple Zone

The crumple zones in the Santro Xing have been further reinforced to conform to the strictest of global safety norms and tested for frontal and offset impact in the most gruelling test track conditions, so that you drive away with complete peace of mind. Take a look at the Multimedia Animation of our Crash Tests.

High Torsion Impact BarsA pair of ultra-high strength steel members are built into the doors of the Santro Xing for additional protection against side impact, while a front impact bar and an engine subframe protect you in the event of a frontal impact.

Crash TestHyundai vehicles are put through rigorous Crash Tests during developmental stage that conform to the exacting standards set by agencies like NCAP and SINCAP. Every effort is made to exceed the stipulated norms to ensure uncompromising passenger safety.

Comfort:The Tallboy design of Santro Xing provides for enough leg, head and elbowroom. The seats provide firm support for thigh and back. The GLS AT variant of Xing is equipped with an option for 4-speed automatic gearbox. This is best suited for urban commuters because it reduces the hassle of frequent gear changing in city traffic. Handling is least to bother about because Santro Xing is very agile. With a short wheelbase and turning radius, it proves ideal for speedy drivers. The superior quality McPherson Strut suspension in the front and 3-link offset coil springs in the rear of the vehicle even-out the bumps on Indian roads.

4-Speed Automatic TransmissionNow enjoy the freedom from stick gear shifting & frequent clutch pedalling with the Santro Automatic.With an electronically controlled 'intelligent' power train system, the Santro Automatic offers the most relaxed way to counter busy city motoring. The 4-speed transmission features a compact ultra-light weight gear train, high performance torque converter and hydraulic-

electronic control, offering four forward gear ratios to deliver a wide array of speeds for varying city traffic conditions.

Maneuverability with Power SteeringWith the 'Easy Drive' power steering of the Santro Xing, squeezing into difficult parking lots and negotiating the rush hour traffic, is not just effortless, but fun as well. The power steering also gives you much greater control of the vehicle, not only in gliding effortlessly over pot holed roads but for enhanced safety in case of accidents like tyre bursts.

Air-Ventilation SystemThe redesigned louvres in the Santro Xing offers much improved air circulation and delivers optimum driver and passenger comfort.

MATERAILS USED IN VEHICLE:1: SteelIn cars, steel is used to create the underlying chassis or cage beneath the body that forms the skeleton of the vehicle and protects you in the event of a crash. Door beams, roofs and even body panels created during auto manufacturing are made of steel on most cars today. Steel is also used in a variety of areas throughout the body to accommodate the engine or other parts. Exhausts are often made from stainless steel, for example. Steel manufacturing has evolved greatly, so carmakers these days can make different types of steel for different areas of the vehicle that are rigid or that can crumple to absorb different impacts. These innovations in automotive manufacturing help keep you safe on the road. 2: Plastic Today's cars now use tremendous amounts of plastics in auto manufacturing. They make up about 50 percent of the construction of new cars today. It's not surprising because plastics are durable, cheap to make and can be turned into just about anything. Car dashboard, gauges, dials, switches, air conditioner vents, door handles, floor mats, seat belts, airbags and many other parts are all made from different types of plastics. In addition to the dashboard parts, many of the tiny parts inside the engine, such as the handle on the oil dipstick, are also made of plastic. Because of their lightweight nature, plastics are being increasingly used in body structures and in engines during automotive manufacturing.

3: Aluminum In the world of auto manufacturing, It's being used increasingly in the car world for its lightweight but tough nature. In 2009, aluminum components made up about 9 percent of the weight in most modern vehicles. Aluminum can be used in automotive manufacturing to create body panels for a lighter, more performance-oriented vehicle. . Wheels are also often made out of aluminum. In addition, more automakers are switching from traditional iron blocks for engines to aluminum construction. It tends to be not quite as durable as iron, but its lighter weight means a big boost in performance. 4: Rubber Automotive manufacturing is the driving force of the rubber industry, as about 75 percent of the world's natural rubber production is used to make tires for vehicles. The rubber tire protects the rest of the wheel and its internal parts from wearing down, which can be good for fuel mileage and road safety. In addition to the all-important tires, parts such as wiper blades, engine mounts, seals, hoses and belts are also made from rubber. As with plastic, it's a very durable, cheap and flexible material that has a wide array of uses in automobiles. 5: Glass. Glass is used in many areas of your car. Obviously, its primary use is to create windshields so you can see properly while remaining safe from any airborne objects. It's also used to create rear and side-view mirrors to boost your view of what's around you while driving. In addition, its cousin fiberglass is also commonly used in auto manufacturing as an insulation material on cars. However, as technology advances, glass is also being used to create more innovative parts on cars. For example, it can be used to create navigation screens and lenses for back-up cameras to allow drivers to have an even better view of what's behind them. 6: copper. Steering wheel - must be a very hard material such as steel and pliable for your hands - rubber with a plastic coating to protect the rubber.

7: lead.

lead plates and sulphuric acid the liquid that circulates around the plates makes the best known vehicle storage battery which lasts 5 to 7 yrs before. 8: fibre. Manufacturing and styling of interiors and seats.

SPECIFICATIONS:Dimensions and Weights Overall Length (mm) Overall Width (mm) Overall Height (mm) Wheel Base (mm) Ground Clearance (mm) Front Track (mm) Rear Track (mm) Boot Space (liter) Kerb Weight (kg) No of Doors 3565 1525 1590 2380 172 1315 1300 218 854 5

Fuel Economy Mileage Highway (km/liter) Mileage City (km/liter) Mileage Overall (km/liter) Capacities Seating Capacity (person) Fuel Tank Capacity (liter) 5 35 16.8 11.8 12.8

Performance Maximum Speed 0-100kmph 1/4 Mile Engine Engine Type/Model Displacement cc Power (PS@rpm) Torque (Nm@rpm) Hyundai Epsilon Engine 1086 63PS @5500rpm 89Nm @3000rpm 160Km/Hour 16.9seconds 20.6seconds

Bore (mm) Stroke (mm) Compression Ratio No of Cylinders (cylinder) Cylinder Configuration Valves per Cylinder (value) Fuel Type Fuel System Transmission Transmission Type Gears/Speeds Clutch Type Final Reduction Gear Ratio SuspensionsFront Suspension Rear Suspension Rear Shock Absorbers

66 77 8.9:1 4 Inline 3 Petrol Multipoint Fuel Injection,

Manual 5Gears Stick gear shifting & frequent clutch

McPherson Strut with Stabilizer Bar Torsional Beam Axle , 3 Link Offset Coil Spring & Hydraulic Damper Hydraulic

Steering Steering Type Power Assisted Minimum Turning Radius (meter) Brakes Front Brakes Rear Brakes Wheels and Tyres Wheel Type Wheel Size Tyres Pressed Steel 13 Inch 155/70 R 13 Radial Ventilated Discs Drums Rack & Pinion Standard 4.4

Calculation of drag coefficient Frontal cross sectional area (A)=( width* height)+2*(mirror area) +2*(tyre area) = (144*132) +2(19*14) +2(21*15) = 20170 square cm = 2.017 square m Velocity of the vehicle (v) = 160 kmph = 44.44 mph Maximum power of the vehicle(P) = 53.6 bhp Maximum speed of the engine(N) = 5500 rpm Radius of the tyre (r) = 0.24m gear ratio = 3 transmission efficiency = 0.90

Torque available at crankshaft (T) = (HP*5252)/N lbft = (53.6*5252)/5500 = 51.183 lbft (1 lbft = 0.138kgm) = 7.06 kgm

Torque available at wheels (Tw) = T*gear ratio*transmission efficiency

= 7.06*3*0.9 = 20.12 kgm Total tractive effort available at wheels (P) = (Tw/r)*g = (20.12/0.24)*9.81 = 822.405 N Total tractive effort available at wheels (P) =1.35*( Av2*Cx/2)

Coefficient of air resistance (Cx) = (P*2)/(1.35*Av2) = (822.405*2)/(1.35*1*2.017*44.442)

= 0.301

Calculation of Vehicle Drag Coefficient and Coefficient of Rolling ResistanceTrials in Direction 1 time sec 0 10 20 30 40 50 60 70 rho g A M time sec 0 5 10 15 20 25 30 35 40 45 50 55 60 65 70 V1 kph 70 68 50 30 19 10 4 0 1 9.81 2.017 897 V actual m/s 19.44 17.92 14.63 10.00 6.39 3.89 2.08 0.37 V2 kph 70 65 51 37 15 9 3 0 kg/m^3 m/s^2 m^2 kg V model m/s 19.44 18.1402 16.93783 15.82311 14.78429 13.81154 12.89659 12.03243 11.21304 10.43324 9.688511 8.974925 8.289016 7.627716 6.98829 V3 kph 70 67 56 38 24 17 8 3 density of air (adjust for your altitude) gravitational constant frontal area mass of vehicle plus occupants F Newtons 233.9809 215.7053 199.9808 186.3655 174.5113 164.1406 155.0302 146.9986 139.8974 133.6041 128.0173 123.052 118.6372 114.713 111.2287 a m/s^2 0.260848 0.240474 0.222944 0.207765 0.19455 0.182988 0.172832 0.163878 0.155961 0.148946 0.142717 0.137182 0.13226 0.127885 0.124001 Sum of Error^2 (minimize by changing Cd and Crr) Drag coefficient Coefficient of rolling resistance Cd = Crr = Error^2 0.00000 0.95812 0.02392 8.39026 23.27248 33.63561 38.51050 43.79686 ######## 0.369681 0.010571 Trials in Direction 2 V4 kph 70 65 50 35 25 15 10 0 V5 kph 70 60 55 38 28 17 8 0 V6 kph 70 62 54 38 27 16 12 5 V avg kph 70.0 64.5 52.7 36.0 23.0 14.0 7.5 1.3

Low Speed Wind Tunnel

TIRE INFLATION PRESSURE:

Cold inflation pressureCold inflation pressure is the inflation pressure of tires before the car is driven and the tires warmed up. Recommended cold inflation pressure is displayed on the owner's manual and on the placard(or sticker) attached to the vehicle door edge, pillar, glovebox door or fuel filler flap. Drivers are encouraged to make sure their tires are adequately inflated, as suboptimal tire pressure can greatly reduce fuel economy, increase emissions, and can lead to premature failure of the tire. Excessive pressure, on the other hand, will lead to blowouts. Tire pressure is measured in psi in the Imperial and customary systems, bar, which is deprecated but accepted for use with SI or the kilopascal (kPa), which is an SI unit.

Hot inflation pressureHot inflation pressure is the inflation pressure of tires after the car is driven and the tires warmed up. Recommended hot inflation pressure is displayed on the owner's manual and on the placard(or sticker) attached to the vehicle door edge, pillar, glove box door or fuel filler flap. Drivers are encouraged to make sure their tires are adequately inflated, as suboptimal tire pressure can greatly reduce fuel economy, increase emissions, and can lead to premature failure of the tire. Excessive pressure, on the other hand, will lead to blowouts.

ERGONOMICS IN SANTRO XINGCOMFORT

A/C with Ozone-Friendly R134a Gas Heater 4 Speed Blower Fan Remote Fuel Lid Opener Remote Tail Gate Release Clutch Foot Rest Power Steering Power Windows Low Fuel Warning Central Locking Clear Headlamps Twin Clear Rear Combination Lamps Driver & Passenger ORVM All Around Tinted Glass Detachable Black Bumper Moulding Waistline Moulding Chrome Radiator Grille New Body Colour Body Colour Coordinated Seat Fabric 3-Spoke Steering Wheel A, B & C Pillar Trims Rear Speaker Grill Ash Tray Cup Holders Room Lamp Floor Console Anti-Submarine Front Seats Rear Seat Double Folding

EXTERIOR ERGONOMICS

INTERIOR ERGONOMICS

Rear Seat Head Restraints (Integrated)

Visibility Test For Santro Xing

SI.N O. 1. 2. 3. 4. 5. 6.

PILLER Piller A (right) Piller A (left) Piller B (right) Piller B (left) Piller C (right) Piller B (left)

ANGLE (DEGREE) 3 4 10 4 6 7 34

Total

Total visible angle:- 326

SEAT ERGONOMICS: Forward Visibility Angle:

Maximum visibility angle

= 30 degree (upper). 20 degree (lower).

Minimum visibility angle

= 20 degree (upper). 10 degree (lower).

Back rest angle Height of backrest Diameter of steering wheel

= 90 to 140 degree. = 57 cm. = 35 cm.

In the fig.-4.7

=10 degree; = (90 to140) degree; =46 degree and h=35 cm

STABILITY OF VEHICLE:Critical speed for toppling and skidding when vehicle moving on a corner with radius of curvature 30m, 40m and 50m. For toppling Vo =(gxr2xhc)

Where hc = height of CG = .795m r =radius of curvature =30m, 40m and 50m. Vo1 Vo2 Vo3 = (9.81x302x.795)= 48.97 kmph = (9.81x402x.795)= 56.55 kmph =(9.81x502x.795)= 63.23 kmph

For skidding Case (1): when road coefficient = 0.5 Vs = ( gr) m/s

Vs1

= ( .5x9.81x30) =43.66 kmph

Vs2

= ( .5x9.81x40) =50.42 kmph

Vs3

= ( .5x9.81x50) =56.37 kmph

Case (2) when = .8 Vs1 Vs2 Vs3 =( .8x9.81x30) =55.23 kmph =( .8x9.81x40) =63.78 kmph =( .8x9.81x50) = 71.31 kmph

Hill side angle: = tan-1b2hc = tan-11.310/(2x.795 ) = 39.48

Radius Of Curvature Vs Critical Skidding Speeds For Different Co-Efficient Of Friction Of Road

Radius of curvature Vs toppling speeds

SAFETY SYSTEMS Dual Member Side Protection Beams Engine Sub-Frame Energy-absorbing steering column Cross bar under dash panel Child-Safety Rear Door Locks Front & Rear Seat Belts High Mounted Stop Lamp (HMSL) Dual Horn Day & Night Inside Rear View Mirror Antilock Braking System (ABS) Optional

ACTIVE SAFETY SYSTEMS AND PASSIVE SYSTEMS:

Active safe ty features ca n help preven t crash s by providing th e e driv er w th bett er mean of contro lli ng th i s e veh icl e and av oid ng hazards. Many i vehicl e fe atures m e an obvious contr ib ution to activ e safe ty su ch as ak , well -main tain ed tires, brak es , lig hts and stee ring Others ar e n so o v u . ot b io s , lk seats and air-conditioning. ie While active safety features can help reduce the chance of a C rash , u fortu ately not all crashes are avoidable. n n

P ssiv a e safety fe atures are des ig ned to preven t o m nim ze in ry r i i ju vehicles occ upants. Some fe ature h lp ab so b crash forces; some s e r occ upants fro m collid ng with th i e vehicl e interio , and o h rs r t e obje cts in id e s th e veh icl e from str iki ng th e driv er pas engers. s It is important to choo se a vehicle with both goo d active and pas ive safety features. s

to th e res tr ai n prevent or

Active safety:1. Crash avoidance: T he most effective active safety feature is the driver. Evenvehicles with the best active safety features can still crash, and it is almost always a driver who is responsible. The best thing you can do to avoid a crash is to drive your vehicle safely.

2. Tyres: T ires are one of a vehicles most important active safety features.Whenever a vehicle accelerates, cor ner s or brak es, it imposes forces on its tires. Goo d tires grip the road to allow a vehicle to stop, go and cor ner safely, which can be crucial in avoiding crashes.

3. Brakes: Goo d brak es are essential for controlling a vehicle and so mu st be wellmaintained. A goo d brake sys tem has the following features: The vehicle should be able to stop in the shor test poss ible distance and still maintain stability. The vehicle can be easily controlled during braking. Br aking per for mance should be consistent with brake pedal press ure.

4. Anti-lock Br ak ing Systems (ABS): The main safety benefit of ABS is vehiclestability and steering during hard braking. With better control of the vehicle, the driver of an ABS- equipp ed vehicle has a better chance of avoiding a crash.An ABS-equipped vehicle has a com ter with sensor s that monitor whee l spee d and pu detect when a whee l is about to lock u p und er hard braking. The comp uter sends a signal to valves that re du ce and reapp ly brake press ure on that whee l several times a second, allowing the whee l to keep rolling. By preventing whee l lock-up, ABS lets the driver brake hard and still retains stee ring control.

5. Handling and stability: A vehicle with goo d handling and stability is not only apleasure to drive; it is also safer to drive. The vehicle holds the road and is more responsive to the drivers com and s. This is achieved throug h a combination of m the vehicles stee ring, suspension, braking, acceleration, body characteristics and weight distribution.

6. See ing and being see n: A safe car should have features that enable the driver tosee clearly and identify poss ible risks, and also allow other road users to see the vehicle and judg e what it is doing. Some of these features are described below.

7. Adj ustability and comfort: Vehicle fittings m st be able to be easily adj usted so uyou are comfortable and in control on the road. All adjustments should lock in place until the occ upant w nts to change them. Mirr ors have already bee n mentioned; a her e are some other features.

8. Minimizing driver distraction: If a vehicles instruments and controls are difficult tosee and use, your att ention is taken away from the road. This is when cras hes can happ en.

Pas ive safety s1. Crush zones and safety cages: The occ up ant compartment is a robust safetyca ge that diverts and diss ipates crash energy a nd pre ser ves the occupants survival space as m ch as poss ible. The safety ca ge should include stro ng pillars u to stop the roo f from collapsing in roll-over cras hes, as well as barr iers to pre vent the whee ls, bonn et or engine intruding into the occ up ant compartment.

2. Frontal impact protection: Ever y new car sold in World mu st comply with one ofthe approved performance-based frontal impact protection stand ards. These stand ards ensure the front crush zo ne, safety ca ge and other occupant protection features wor k together to provide a prescribed level of driver and pass enger safety in a frontal crash. 3. Side impact protection: S ide impact cras hes can be particularly dang ero us beca use ther e is no roo m for large crush zo nes to protect an occ up ant f rom crash forces. The doo r can be smashed into an occ up ant or the occupants head may be struck, causing potentially fatal injuries.

4. Safety belts: Three -point lap and shoulder safety belts are the best means ofocc up ant protection in almost all types of cras h. Wearing a safety belt can halve the risk of being injured or killed in a crash.

5. Seats: A vehicles seats can be ver y effective pass ive safety features. A seatshould b e comfortable , b u t must also be sturdy enoug h to withstand a lot o fo f rce and prote ct its occupant in a crash. Anti-submarining seats:- Most new ca rs have front anti-submarining seats designed to prevent the occ up ants slipping under the lap section of the safety belt and suffering abd ominal injuries in a crash.

6. Head restraints: Head restraints are important safety features and shouldpreferably be fitt ed to all seats - front and back.

7. Safe vehicle interiors: Most injuries in a crash occur when an occupant collideswith the stee ring whee l, dashb oard, doo r or other interior surface. Improving the safety of the interior of the occ up ant com artment, can reduce injury severity. p

8. Load restraint: Load restraint is an ess ential consideration if the vehicle you arebuying is likely to be heavily laden with parcels, equipment or bagg age, as these can ca use serious injuries in a crash if they are not restrained. Even a small object left on the parcel tray behind the back seat can become a dang ero us projectile.

9. Fire prevention & protection: Fi re prevention and protection is an important fac torin vehicle safety. The fuel tank and pipe conn ections should be designed and positioned to minimize any likely damage in a crash.

S sp sio sy u en n stem a dty es o ru b b sh g u s n p f b er u in s sed to red ce n ise a dv ra n u o n ib tioR b er B sh ub u es A bushing or rubber bushing is a type of vibration isolator. It provides an interface between two parts, damping the energy transmitted through the bushing. A common application is in vehicle suspension systems, where a bushing made of rubber (or, more often, synthetic rubber or polyurethane) separates the faces of two metal objects while allowing a certain amount of movement. This movement allows the suspension parts to move freely, for example, when traveling over a large bump, while minimizing transmission of noise and small vibrations through to the chassis of the vehicle. A rubber bushing may also be described as a flexible mounting or antivibration mounting.

Suspensions systems:1. McPherson Strut with Stabilizer Bar (front) Although it is a popular choice due to its simplicity and low manufacturing cost, the design has a few disadvantages with regards to the quality of ride provided and how it affects the handling of the car. Geometric analysis shows it cannot allow vertical movement of the wheel without some degree of either camber angle change, sideways movement, or both. It is not generally considered to give as good handling as a double wishbone suspension, because it allows the engineers less freedom to choose camber change and roll center. Another drawback is that it tends to transmit noise and vibration from the road directly into the body shell, giving higher noise levels and a "harsh" feeling to the ride compared with double wishbones, requiring manufacturers to add extra noise reduction or cancellation and isolation mechanisms. Also, because of its greater size and robustness and greater degree of attachment to the vehicle structure, when the internal seals of the shock absorber portion wear out replacement is expensive compared to replacing a simple shock absorber.2. Torsional Beam Axle(rear)

A torsion beam suspension is a vehicle suspension similar to a trailing arm suspension but where both trailing arms are connected by a beam.In contrast to a torsion bar suspension, the main weight bearing springs are usually coil springs, either mounted over the shock absorbers or independently from them. Obviating anti-roll bars, the central torsion beam allows for a limited degree of freedom of each wheel when forced. This semi-independent suspension has been very widely used for decades by the great majority of compact European and Japanese front wheel drive cars up to Golf-size. It is cheap to design and manufacture, compact with little boot space intrusion, and although ride and handling are theoretically inferior to more sophisticated designs, it has been used even in the sportier Volkswagen Golf GTI.