Subject: Automobile Engineering

Topic: Body Engineering & Chassis

Difficulty: Medium

Vehicle body is a superstructure. Body is either integral with the under frame or bolted to the frame. The body & chassis make complete vehicle. A body consist of a doors, windows, engine covers, roof, luggage, cover etc. Different type of body's is attached to chassis according to application.
The important design considerations are as follows:
i)Customer appeal of style
ii)Reduction in body weight to improve capacity & fuel economy.
iii)Aerodynamic characteristics which determine the fuel consumpton, speed. &_stability in cross wind. The positive pressure at front should be decreased & deflated smoothly for the prevention of eddies creations.

Materials for body work:
Steel is used in majority of cases being the cheapest along with the ease with which it can be stamped out to form various shapes. Alloying elements are added improve its ability to be formed into deeper depressions without wrinkling or tearing in the manufacturing presses. Aluminium has also been used by some manufacturers because of its better formability, lightness & anti-rusting qualities, though its main disadvantage is lesser stiffness & rigidity.
Thermoplastics are quite often used for components like boot cover, grills, etc. Fiberglass are being used for the body shells.
Toughened or tempered glass has been used for the automobile windscreen & other window panes laminated glass is used for windscreen.

layouts of passenger bus:-
Chasis is a main structure, upon which all the major component of an automobile which are..necessary to proper the vehicle are assembled. Chasis comprises of everything of a vehicle except the body, cabin & equipment. The automobile chassis consist of following components:
i) Frame:- It is a skeleton to hold the major unit together There are of two types: a) The conventional pressed steel frame to which all mechanical unit are attached.
b) Integral or frameless construction in which body construction perform combine function of body & frame. So, it decreases the weight & save fuel consumption also reduces manufacturing cost but increases repair cost if damage occur during accident.

ii) Engine – It provides motive power to perform the various function of vehicle.
iii) Transmission System - It consists of clutch, gearbox,universal.joint, propellers shaft, differential, rear axle, wheel.
iv) Suspension System - This system isolates the vehicle body from the road shock which are in the form of rolling, bouncing & pitching. It provides comfort to passenger & reduce the steps in frame.
v) Controls- Vehice includes steering system, braking system & engine control.
vi) Electrical control: This system consists of supply systems Battery & dynamo starting relay, ignition system (Battery or magneto-ignition system), other miscellaneous system like driving light signalling, reverse,light, panel light, wiper ,etc. vii) Radiater: It is advice used to recool the hot engine cooling water for recirculation purpose. The radiator is connected to engine by base pibe to allow the cooled water circulation.