AM09 403

AUTO CHASSIS

SYLLABUS

MODULE-I MODULE-III MODULE-IVMODULE-II• POWER

PLANT

• CHASSIS

• FRAMES

• FRONT AXLES

• STEERING SYSTEMS

• SUSPENSION

• DRIVE LINE

• BRAKES• WHEELS

• TYRES

AUTOMOBILE ENGINEERING• Automobile engineering is a branch of engineering which deals

with everything about automobiles and practices to propel them.

• Automobile is a vehicle driven by an internal combustion engine and it is used for transportation of passengers and goods on the ground.

• Examples : Car, jeep, bus, truck, scooter, etc.

MAIN COMPONENTS OF THE AUTOMOBILEThe automobile can be considered to consist of five basic components (a) The Engine or Power Plant : It is source of power.

(b) The Frame and Chassis : It supports the engine, wheels, body, braking system, steering, etc.

(c) The transmission: which transmits power from the engine to the car wheels. It consists of clutch, transmission, shaft, axles and differential.

(d) The body and Controls.

(e) Accessories: including light, air conditioner/hearer, stereo, wiper, etc.

Layout of complete system of Automobile

Layout of the transmission system

Engine or Power Plant

• The engine is the power plant of the vehicle.

• In general, internal combustion engine with petrol or diesel fuel is used to run a vehicle.

• An engine may be either a two-stroke engine or a four-stroke engine.

• An engine consists of a cylinder, piston, valves, valve operating mechanism, carburettor (or MPFI in modern cars), fan, fuel feed pump and oil pump, etc.

• Besides this, an engine requires ignition system for burning fuel in the engine cylinder.

THE POWER PLANT• Gas turbines also have been used in

vehicles

• Now, electric batteries for propelling the vehicle

ARRANGEMENT OF POWER PLANT

1.Front engine FWD• The power is transmitted to front axles, from the front engine

(Front Wheel Drive)• A few advantages are:i. The propeller shaft is eliminated. This permits low chassis

heightii. The pulls the car than pushing it, avoiding skidding

tendency.iii. Better road adhesion.• A few disadvantages are: i. The whole arrangement over front wheels is complicated.ii. Constant velocity joints have to be used instead of

universal jointsiii. Decrease of tractive forces when the vehicle is up the

grade.

Layout of FWD

2.Front engine RWD• The power is transmitted to rear axles, from the front

engine (rear Wheel Drive)• A few advantages are:i. The whole arrangement over front wheels is easy.ii. universal joints have to be used instead of

Constant velocity joints iii. increase of tractive forces when the vehicle is up

the grade.• A few disadvantages are: i. The propeller shaft is engaged. This permits high

chassis heightii. Transmission loss is high.

3.Rear engine RWD• The engine is placed at the rear and the rear wheels

are the driven wheels• Advantages are:i. Better tractive forces up the gradeii. Front axle construction is simplifiediii. Absence of propeller shaft allows decrease in

chassis height• The disadvantages are:

i. May lose balance at high speeds.ii. Complicated linkage is required between the

engine, clutch and gearbox.iii. Rear position of engine, cooling effect is reduced.

4.Front engine four wheel drive

• Vehicles which operate on rough roads and unexpected road profiles, all the four wheels are the driving wheels.

• It has got an extra transfer box, which divides the torque between front and rear wheels.

• Also there is a provision for disengaging the front wheels when not required.

4WD

Transfer Box in 4WD

ADVANTAGE OF 4WD

• The main advantage of the 4WD is that when any wheels fall into a ditch or a hole, they can be driven out with the help of other wheels or power being delivered to the same wheel

• But this advantage can only at the cost of extra fuel consumption.

CHASSIS AND FRAMES

CHASSIS• Chassis is a French term which is now denotes

the whole vehicle except body.

• “Chassis consists of engine, power train, brakes, steering system and wheels mounted on a frame”.

REQUIREMENTS OF FRAMES

4.Sub frame