CHASIS OF AN AUTOMOBILE - INBRIEF

 Chasis

•What is a chassis ?

          -It is a completed vehicle except body

         - i.e. all the components  of engine, basic structure ,

          transmission system , control system and auxiliaries

          together know as chassis 

 

            •Does all vehicles have same type of chassis?

               - No

            •Why ?

               - With respect to engine fitting and construction 

                chassis varies from one vehicle to other 

 

Types of Chassis

•  According to the construction of frame

           1.    Ladder chassis

           2.    Tubular space frame chassis

           3 .   Back bone chassis

           4.    Monocoque chassis

•  According to the position of engine

        1. Full forward chassis

        2. Semi forward chassis

        3. Engine at front chassis (Conventional chassis)

        4. Engine at center

        5. Engine at rear chassis

•  According to the type of vehicle

           1. Bus chassis

           2. Car chassis

           3. Truck chassis

           4. Motorcycle chassis 

•  According various applications

            1. Long wheel base chassis

            2. Over hanging chassis

            3. Half-integral and half-frame chassis

 Types of Chassis Based on Construction of Frame

1.Ladder Chassis

         –This is earliest kind of chassis 
         –As name indicates, it looks like a ladder 
         –Two longitudinal rails inter connected by several lateral and cross  member 
         –Longitudinal members are the main stress members 

Disadvantage:

         - Not strong enough 

           Eg :

                - Nearly all cars until the early 1960s

                - Most SUVs (Sports Utility Vehicles) 

Tubular Space Frame Chassis 

•It employs dozens of circular-section tubes

•Tubes position in different directions to provide  mechanical strength against forces from any where

•These tubes are welded together and forms a very complex structure

•This chassis is very strong in any direction when compared to ladder chassis

    Eg: Ferrari and TVR cars

 

 Backbone Chassis

•A strong tubular backbone (usually in rectangular section ) connects the front and rear axle

•The whole drive train, engine and suspension are connected to both ends of the back bone

•Does not provide protection against side impact

•Eg: Small sport cars such as Élan Mk-ll, Macros 

 

 Monocoque Chassis

•Monocoque means ‘single shell’

•It is a one-piece structure which defines the over all shape of the car

•This chassis in already in corporated with the body in a single piece

•The one-piece chassis in actually made by welding several pieces together

•Inherently good crash protection and space efficient 

 

Types of Chassis Based on Engine Position

 

Full Forward Chassis

 •Engine fitted in front of driver seat

•Eg:  Cars and old TATA trucks 

Semi Forward Chassis

     •Half engine fitted in the driver’s cabin and half out of the driver’s cabin 

     •Eg:  Standard  trucks and TATA - Mercedes' trucks

Conventional Chassis 

•Engine fitted in front of drive’s cabin

      • There Types 

       1.Front engine real wheel drive

       2.Front engine front wheel drive

       3.Front engine in a cross manner, front wheel drive 

 

Engine at Center of the Chassis

         •Engine is fitted into its center under the chassis

        Eg:- Royal tiger wood master buses 

 

Engine at Rear Chassis

        •Engine fitted at the rear of the vehicle  

        •The drive is provided through the real wheel 

       Eg:Renault, Daulphine, Volkswagon and some of the Leyland buses

 

Overhang Chassis

 

•      Chassis is extended before front axle and after the rear axle, to accommodate more floors space

 

Type of Chassis on Various Applications

 

Long wheel base Chassis:

•Provided with longer wheel base, to accommodate and to carry more load

•Accordingly longer chassis is required

 

Half-integral and Half-frame Chassis

 

•Half frame is bolted to the floor of the vehicle

•Half frame is fixed at front end

  Eg:  Ambassador cars , Fiat cars

 

Chassis of an Automobile

•It is skeleton of the automobile

•It is a complete vehicle except the body

•Whole vehicle excluding the additional fitment

•Plural form of chassis is also “chassis”

 Components of Chassis

1.Engine

2.Basic structure

3.Transmission system

4.Control systems

5.Auxiliaries

Engine

•         It is also called as power plant of the automobile

•         It provides necessary power to run the automobile

•         Internal Combustion Engines (I.C.Engines) are used in automobiles

Basic Structure

The following components combined together is known as the basic structure of an automobile

               1. Frame

               2. Suspension System

               3. Axles

               4. Wheels

Transmission System

•           In automobiles, the power developed by the engine is ultimately aimed to turn  the wheels so that the vehicle can move on the road

                     

•             Power developed by the engine will be transmitted through  various components which finally turn the wheels

•             These components all together are  known as Transmission system

   

Components of transmission system

•         Clutch

•         Gear box

•         Universal joints

•         Propeller shaft

•         Differential

Control Systems

     when an automobile is running on the road, the

      following operations are performed :

•       Reduction or increase of the speed of vehicle
•       Stopping of the vehicle 
•       Taking turn to change the direction of the vehicle

To perform these operations, a vehicle needs  various control systems

     Two types of control systems are there:

•          1. Steering System
•                - To change the direction of the vehicle
•          2. Brake System

o   To slow down or stop the vehicle

Auxiliaries (Electrical)

       In automobiles, power is required not only to run the vehicle, but also required

•               To blow horn

•               To start the engine

•                     For lighting

•                     To show various gauge readings such as                           

           speedometer and fuel level indicator

       Battery and various electrical circuits, which are provided in the automobiles to meet these requirements are known as auxiliaries

Various auxiliaries (electrical circuits) in the automobiles

–        Starting circuit

–        Charging circuit

–        Lighting circuit

–        Horn circuit

–        Gauges circuit

Main Components of an Automobile

 

The following components combined together is known as the basic structure of an automobile

               1. Frame

               2. Suspension System

               3. Axles

               4. Wheels and Tyres

 Frame

•It is the main part of the vehicle

•

•Remaining parts of chassis are mounted on it

•

•It is a rigid structure

•It is generally comprises of two side members and several cross members connected together

•It is narrow at the front  and widened out at rear 

•The engine is mounted in the forward end of the frame 

•At the rear end of the frame, the rear axle housing is attached through the rear spring (suspension)  

•Carries weight of the vehicle and passengers 

•It should be strong enough to resist stresses 

 

Frame of an automobile

 

Frame of a car

 Suspension System

 

•It provides cushioning to the road shocks and vibrations and prevents them from being transferred to the frame

 

 Suspension System in an automobile

•It consists of springs to absorb the road shocks

Suspension System in a Car

 Axle

•It acts as a beam supported at the ends 
•There are two types of axle.
     1.Front axle
     2.Rear axle

Front Axle 
•Carries weight of the front portion 
•Facilitates steering and suspension system

Front axle of an automobile 

Rear Axle

•Carries weight of the rear portion 
•Facilitates suspension system 
•Transmits the drive to rear wheel

Wheels

•To drive as well as support the vehicle

•Two types

      1. Front wheels  -  To steer the vehice

      2. Rear wheels  -  Driven by rear axle

•The tyre is made of rubber

•It is attached to the outer rim of the wheel

•A tube is fitted inside the tyre and filled with air