THIS PRESENTATION INCLUDES SEVERAL TRANSMISSION SYSTEM IN AN AUTOMOBILE ALONG WITH CLUTCH ASSEMBLIES

1. Transmission System
in an Automobile
Aakash Varshney
Amity University

2. What is a Transmission?
The word ‘Transmission’ means the whole of the
mechanism that transmits the power from the engine
crankshaft to the rear wheels, providing the suitable
variations of the engine torque at the road wheels,
whenever required.

3. Necessity & Types Of Transmission
 Variation of resistance to the vehicle motion at various speed.
 Variation of tractive effort of the vehicle available at various speeds.
 Provides means of connection and disconnection of engine with power train
without shock and smoothly. It also Provides a neutral position.
 To provide a means to vary the leverage or torque ratio between the engine &
the road wheel as required.
Types:
 Manual transmission
 Fully automatic Transmission
 Semi-Automatic Transmission
 Continuously Variable Transmission

4. Manual Transmission
Components of Manual Transmission:
Clutch
Gearbox
Differential

5. What is clutch?
It is a mechanical device which engages & disengages the power
transmission, especially from driving to the driven shaft.
It is located between flywheel and gearbox.

6. Construction of Clutch

7. Working of the Clutch
 Clutch fully depressed:
The clutch is fully disengaged when the pedal is fully depressed. There will be no
torque being transferred from the engine to the transmission & wheels. Fully
depressing the clutch allows the driver to change gears or stop the vehicle.
 Clutch slips:
The clutch slips is the point that vary between being fully depressed and released. The
clutch slip is used to start the vehicle from a stand still. It then allows the engine
rotation to adjust to the newly selected gear ratio gradually . It is recommended not to
slip the clutch for a long time because a lot of heat is generated resulting in energy
wastage.
 Clutch fully realeased:
The clutch is fully engaged when the pedal is fully released. All the engine torque will
be transmitted to the transmission. This results in the power being transmitted to the
wheels with minimum loss.

8. How it Works

9. Types Of Clutches

10. Gear Box
 Gear Box varies the leverage (speed ratio & hence torque ratio) between the engine &
driving wheels.
 It is located between clutch & propeller Shaft.
 It is provided with either 4 speed or 5 speed ratios or more depending on design.
 Gear ratio is varied by Gear shift lever.
Types Of Gear Box:
 Sliding mesh type
 Constant mesh type
 Synchromesh type

11. Sliding Mesh Gear Box
 Oldest and the simplest type of transmission.
 Spur gears were used.
 Main shaft gears splined to the main shaft.
 Gear shift is achieved by sliding the gears on main shaft
 Low mechanical efficiency.
 Noisy operation.

12. Constant Mesh Gear Box
• The gears on the main shaft and lay shaft are in constant mesh.
• Main shaft gears are free to rotate.
• Gear engagement is achieved by dog clutches splined to the main shaft.
• Helical gears are used.
• Example: Fortuner, Innova, Corolla .

13. Synchromesh Type Gearbox
 Gears are in constant mesh.
 Instead of dog clutch synchronizer unit is used.
 Each pair of gear has one synchronizer unit.
 Gears are first brought into frictional contact which
equalizes their speed after which the actual
engagement takes place.
 Example: Santro, Accent, Indica,
 Octavia etc.

14. Differential
Differential is a mechanism which provide different
speed to tyres at cornering.
It provides equal torque on both tyre not power.

15. Automatic Transmission System
 Mechanical efforts are reduced very much.
 Different speeds are obtained automatically.
 Also known as Hydramatic Transmission.
 Contains epicyclic gear train, fluid coupling & torque convertor.
 Used in Toyota, Skoda & Lexus etc.
Stages of Automatic Transmission System
 Park: Park mode will lock the transmission, restrict the vehicle from moving.
 Reverse: Allowing the vehicle to move backward.
 Neutral: Neutral mode disconnects the transmission from wheel.
 Low: Allow us to lower the speed of vehicle to move on hilly & middy areas.
 Drive: Allows the vehicle to move & accelerate through a range of gear.

16. Semi-Automatic Transmission
 Also known as Dual Clutch Transmission (DCT).
 In DCT system two clutches are used.
 First clutch is engage with even gears.
 second clutch is engage with odd gears.
 The gear are controlled hydraulically by a electronic control unit (ECU) which sense
the gears position and shifting.
 Used in Volkswagen, BMW, Porsche.
Advantages:
 No power interruption at gear shifting.
 Very smooth gear-shift operations.
 Less fuel consumption.
 Better drive and Better comfort.
 Drive faster and faster.

18. Continuously Variable Transmission
Working of CVT:
CVT transmission operates by varying the working diameters of the two main pulleys in
the transmission.
When actuated, the cylinder can increase or reduce the amount of space between the
two sides of the pulley.
A CVT operates on three main mechanical components: a variable input driving pulley,
an output (driven) pulley, a metal belt. Used in Audi A4,A6, Nissan Murano, Honda HR-
V.
Benefits:
Provide engine torque in optimum condition (road loads / drive shaft torque).
No shift clonk.
Transmission ratio can be adjusted continuously.
Improved fuel efficiency.
Better acceleration.
Eliminates gear hunting especially when going up a hill.

19. Pulley Based CVT

20. Thank You