4. Body Engineering and Safety Devices

2. Components of Body

3. Body styles.

Classification of Car Segments

As per SIAM (Society of Indian Automobile Manufacturers)

The classification of segments are done as per length of the vehicle, (Passenger car segment)

A1 - Mini - Upto 3400mm (M800, Nano)

A2 - Compact - 3401 to 4000mm (Alto, wagon r, Zen,i10,A-star,Swift,i20,palio,indica etc)

A3 - Midsize - 4001 to 4500mm (City,Sx4,Dzire,Logan,Accent,Fiesta,Verna etc)

A4 - Executive - 4501 to 4700mm (Corolla,civic,C class,Optra,Octavia, etc)

A5 - Premiun - 4701 to 5000mm (Camry,E class,Accord,Sonata,Laura,Superb,etc)

A6 - Luxury - Above 5000mm (S class,5 series etc)

B1 - Van - Omni, Versa, Magic etc

B2 - MUV/MPV - Innova, Tavera, Sumo etc

SUV - CRV, Vitara etc

Types of bodies: shell forming the exterior of a car.Hatchback: two-door passenger compartment with a door at the back.Sports car: small, two-seated automobile.Four-door sedan: passenger compartment with four doors and four side windows.Limousine: large, six-seated passenger compartment.

Convertible: car with a removable roof.Hardtop: two-door passenger compartment.Van: small vehicle used to carry baggage; a small van.Pick-up truck: a small truck.

Procedure of painting: (Note: Credit shall be given to any other suitable Procedure)1) Thoroughly wash the vehicle.2) Carryout protective and anticorrosive treatment.3) Spray a thin coat of primer. Allow to dry for 15 min.4) Apply three full coats of surface allowing 10 – 15 minutes between the coats.5) Allow it to dry for 1 hour. Then wet flat with P 600 grade paper.6) Apply stopper (putty) wherever necessary allowing 15 to 20 minutes between the layers.7) Allow to dry for 1 to 1½ hours.8) Spray surface to stop-up areas and flat with P 600 grade paper.9) Blow off vehicle with air gun and tack off.10) Spray finishing material, apply one coat and allow it to dry for 15 to 30 minutes. Then applysecond coat.11) Allow overnight drying. Wet flat with P 800 grade paper and dry with air gun.12) Spray double header coat.

8. Safety Devices:

a. Air Bag:

Air bags are designed to keep your head, neck and chest from slamming into the dash board,

Working of Air Bag

As vehicle comes across the impact, the sensor detects it and triggers the inflator. Once the electricalcircuit has been turned on by the sensor, a pellet of sodium azide (NaN3) is ignited. A rapid reactionoccurs, generating nitrogen gas (N2). This gas fills a nylon or polyamide bag at a velocity of 150 to250 miles per hour. This process, from the initial impact of the crash to full inflation of the airbags,takes only about 40 milliseconds. Thus minimizing the injury to the passenger or driver. When N2generation stops, gas molecules escape the bag through vents. The pressure inside the bag decreasesand the bag. Deflates slightly to create a soft cushion. By 2 seconds after the initial impact, thepressure inside the bag has reached atmospheric pressure.

Function: (Any 01)1) To provide an additional level of protection in the event of a car accident.2) Air bags supplement the safety belt by reducing the chance that the occupant's head and upperbody will strike some part of the vehicle's interior.3) It help reduce the risk of serious injury by distributing crash forces more evenly across theoccupant's body

Material: Nylon or polyamide bagLocation:1. Front air bag- In steering wheel & in dashboard2. Side Air bag: In doors.

b. Exhaust brake:

This is an auxiliary brake (a non –service brake) use to work when the vehicle is either moving on a long downhill gradient, or in busy trafficwhere has to slow down continuously over a large distance. It consists of pressure regulator, Foot control valve, Air cylinder, Butterfly valve andLinkages. In it, the pressure regulator is common with the air (service) brakeWhen the exhaust gas brake is to be applied, the driver presses upon the control valve by his foot.This allows flow of compressed air from the air cylinder, which in turn operates the linkage toclose the butterfly valve at the exhaust manifold. It prevents exit of the exhaust gas intoatmosphere and diverts it to apply the brakes. As soon as the foot is taken- off the foot controlvalve, the brake is released. In this way, this type of brake effect fuel economy of vehicle.

c. Central Locking:

Power door locks (also known as electric door locks or central locking) allow the driver orfront passenger to simultaneously lock or unlock all the doors of an automobile or truck, bypressing a button or flipping a switch.

Advantages of central locking system: (Any 02)1) All the doors and luggage compartments can be locked or unlocked simply by operating one key.2) It Indicates open door with flash3) Locking/ unlocking can be done by remote4) In case of failure of electronic system, the manual locking is still possible.

Disadvantages of central locking system: (Any 02)1) It is not convenient in case of accident because occupant may not open the door in emergencysince all doors are centrally locked.2) It’s initial and maintenance cost is high.

d. Collapsible steering-The design of these columns is such that they collapse due to impact forces caused during head-oncollision of the vehicle. The collapsing columns ensure greater safety to the driver by minimizingor avoiding a direct severe impact to him.Types of collapsible steering: (Any 04)1) Mesh type jacket column.2) Ball type jacket column.3) Corrugated deformable section type column,4) Telescopic type column.5) Hooks joint type column.