Introduction to Automobile The Layout -by Atul Katti

Components of an Automobile The basic structure The power unit The transmission system The auxiliaries The controls The superstructure

The Basic Structure (Chassis) This is the unit on which the other units are mounted. It consists of:- Frame The Suspension system Axles Wheels Tyres

1. Frame There consists of two distinct forms construction in common use: The conventional pressed steel frame to which all units are mounted The integral or frameless construction, in which the body structure is so designed so as to combine the functions of body and frame.

Frameless - Advantages Reduced weight and consequent saving in fuel consumption Lower manufacturing costs Safety to passengers Increased stability of the automobile

Disadvantages Reduction in strength and durability Economical only if it is adopted in mass production Increased cost or repairs Convertible cars are difficult to design in frameless construction

2. Suspension System The objects of the suspension are: To prevent the road shocks from being transmitted to the vehicle components To safeguard the occupants from road shocks To preserve the stability of the vehicle while in motion

Suspension system Leaf Springs

Suspension system There are two distinct types of suspension systems: The conventional system, in which the road springs are attached to a rigid beam axle. The independent system, in which there is no rigid axle beam and each wheel is free to move vertically

Suspension system

3. Axles It is the wait carrying members, may be on the rear or front, are beams supported at ends. Axles are subjects to different kin of loads: Vertical load due to self weight A fore and aft load due to driving and braking Torque reactions due to drive and brake Side thrust due to centrifugal force during conference

Axles There are three different types live rear axles Fully floating type Three quarter floating type Semi-floating type

4. Wheels Different types of wheels have been used in automobiles over generations according to the requirement Wire-spoked wheels Pressed steel wheels Light alloy wheels

The Power Plant (Engine) The engine provides the power to move the vehicle It generally consists of an IC engine, either SI or CI Gas turbines also have been used in vehicles Now, electric batteries for propelling the vehicle

The Transmission System The transmission system consists of a Clutch, Gear box, Propeller shaft, and Differential

Layout of the transmission system

The Transmission System The functions of a transmission system are: To disconnect the engine from road wheel when desired To connect the engine to the driving wheels without shock To vary the leverage between the engine and the driving wheels

The Transmission System To reduce the engine speed permanently in a fixed ratio To turn the drive through a right angle To make provision for the flexing of the road springs

The Transmission System The various components which perform the above mentioned functions are: Clutch:- To disengage the system from the engine and to engage without shock to road wheels Gear box:- Provides the necessary leverage variation between the engine and road wheels

The Transmission System Bevel pinion and crown wheels:- They turn the drive round through 90° and also provide permanent reduction in speed Universal joints:- Provide for the relative movement between the engine and the driving wheels due to flexing of road springs. Differential:- Helps to attain different speeds at different wheels while taking a turn

Different types of arrangements The different types of the arrangement of transmission could be Front engine and front wheel drive Rear engine and rear wheel drive Front engine and four wheel drive

Front engine FWD The power is transmitted to front axles, from the front engine (Front Wheel Drive) A few advantages are: The propeller shaft is eliminated. This permits low chassis height The pulls the car than pushing it, avoiding skidding tendency. Better road adhesion.

FWD

Layout of FWD

FWD A few disadvantages are: The whole arrangement over front wheels is complicated. Constant velocity joints have to be used instead of universal joints Decrease of tractive forces when the vehicle is up the grade.

Rear engine RWD The engine is placed at the rear and the rear wheels are the driven wheels Advantages are: Better tractive forces up the grade Front axle construction is simplified Absence of propeller shaft allows decrease in chassis height

RWD The disadvantages are: May lose balance at high speeds. Complicated linkage is required between the engine, clutch and gearbox. Rear position of engine, cooling effect is reduced.

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

4WD Transfer Box in 4WD

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.

Classification Automobiles can be classified in different in ways according to:- Use Mopeds Motor cycles, scooters Cars, jeeps Buses and trucks

Classifications Capacity Make and model Heavy transport Light weight transport Make and model Honda, Bajaj, TVS, etc. Maruti Suzuki, Tata, Mahindra etc. BMW, Audi, Ford, Mitsubishi etc.

Classifications Fuel Used Body style Petrol vehicles Diesel vehicles Closed cars e.g., sedan, coupe etc. Open cars e.g., convertible Special styles e.g., estate cars, station wagons etc.

Classifications Transmission Manual Semi-automatic Fully-automatic Continuously variable transmission Automated manual

Car Body Styles Closed cars: Sedan – has two or four doors, single compartment with two rows of seats. Hatchback – A sedan with a door at the back Coupe – only one row of seats for two persons. Only two doors are provided.

Different Closed Cars Honda Sedan

Different Closed Cars Suzuki SX4

Different Closed Cars Ford Fiesta 5 door hatchback

Different Closed Cars Honda Civic Hatchback

Different Closed Cars Honda Genesis Coupe

Different Closed Cars Honda Accord Coupe

Different Closed Cars BMW X Coupe

Car Body Styles Open cars Sports – Has two doors or less, provided with a collapsible hood, a fold-flat windscreen and removable side-screen. Convertible – Roof in this is of folding type. So the car roof can be closed or opened.

Different Open Cars Peugeot 9009 Sports Car

Different Open Cars Dodge Viper Sports Car

Different Open Cars Audi Sports Car

Different Open Cars Ford Mustang Convertible

Different Open Cars BMW M3 Convertible

Different Open Cars BMW M6 Convertible

Different Open Cars Chevrolet Camaro Convertible

Car Body Styles Special styles Estate car – A sedan with the passenger roof extended up to rear end. Rear seats are usually collapsible for loading. Station wagon – Rear doors and four or five person seating capacity.

Special Style Cars Mercedes AMG Estate

Special Style Cars Audi RS 6 Estate Car

Special Style Cars Renault Clio Estate

Special Style Cars Ford Mustang Station Wagon

Special Style Cars Station Wagon

Special Style Cars Station Wagon

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