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2. Seminar By:
AKSHAY METKARI

3. CONTENTS
INTRODUCTION
WHAT IS TRANSMISSION ?
TYPES OF AUTOMATIC TRANSMISSION
TRANSMISSION COMPONANTS
CLUTCH PACKS
BANDS
TORQUE CONVERTER
HYDRAULIC SYSTEM
COMPUTER CONTROLS
AUTOMATIC TRANSMISSION CARS IN INDIA
CONCLUSION

4. INTRODUCTION
The modern automatic transmission is by far, the
most complicated mechanical component in today’s
automobile.
Automatic transmissions contain Mechanical
systems, Hydraulic systems, Electrical systems and
Computer controls, all working together in perfect
harmony which goes virtually unnoticed until there
is a problem.

5. WHAT IS TRANSMISSION ?
 The transmission is a device that is connected
to the back of the engine and sends the
power from the engine to the drive wheels
 Purpose of the transmission is to provide high
torque at the time of starting the engine, hill
climbing , accelerating and pulling a road.

6. TYPES OF AUTOMATIC TRANSMISSION
1. Rear wheel drive
2. Front wheel drive

7. REAR WHEEL DRIVE
 The transmission is usually mounted to
the back of the engine.
 Power flow on this system is simple
and straight forward going from the
engine, through the torque converter,
then through the transmission and drive
shaft until it reaches the final drive
where it is split and sent to the two
rear wheels.
 Example of rear wheel – Alpha Romeo
Alfeta in early 70’s

8. REAR WHEEL DRIVE

9. FRONT WHEEL DRIVE
 On a front wheel drive car, the transmission is usually
combined with the final drive to form what is called a
transaxle.
 Transaxle is a device set up in the transmission gear box,
clutch, final drive, combined into a single unit.
. Front-wheel-drive layouts are those in which the front
wheels of the vehicle are driven. The most popular layout
used in cars today is the front-engine, front-wheel drive,
with the engine in front of the front axle, driving the front
wheels.
 This layout is typically chosen for its compact packaging.
 Front axles are connected directly to the transaxle and
provide power to the front wheels.

10. FRONT WHEEL DRIVE

11. P = Park
R = Reverse
N = Neutral
D = Drive

12. TRANSMISSION COMPONENTS
 Planetary Gear Sets
 Hydraulic System
Oil Pump
Valve Body
Clutches
 Band
 Seals and Gaskets
 Torque Converter
 Governor
 Computer Controls

13. PLANETARY GEAR SETS
A gear set in which all of the gears
are in one plane, grouped around each
other like the planets around the sun.
The central gear is called the "sun
gear". In mesh with it is a circular
grouping of gears, called "planet
gears", mounted on a rotating carrier.
The planet gears also engage teeth on
the inner periphery of the "ring gear".
By holding any one of the three gear
elements motionless, different ratios
can be produced between the other
two. Planetary gear sets are common in
automatic transmissions.

14. CLUTCH PACKS
A clutch is a mechanical
device which provides for
the transmission of power
(and therefore usually
motion) from one component
(the driving member) to
another (the driven
member).
the simplest application
clutches are employed in
devices which have two
rotating shafts.

15. TORQUE CONVERTER
•Torque converter is a form
of fluid coupling.
•It uses a fluid and vaned
rotors to transmit power
between shafts. The torque
converter is filled with ATF.
•When the engine runs,
power flows from the
crankshaft through the fluid
to the transmission input
shaft.
Torque converter 3D animation.mp4

17. HYDRAULIC SYSTEM
 The Hydraulic system is a complex maze of
passages and tubes that sends transmission
fluid under pressure to all parts of the
transmission and torque converter
 It works with some components.
 Oil Pump
 Valve Body

18. GEAR PUMP
OIL PUMP
• Produce all the oil pressure that is
required in the transmission
• The oil is then sent, under
pressure to the pressure regulator,
the valve body and the rest of the
components, as required.

19. VALVE
BODY
• The brain of the automatic
transmission
• Contains a maze of channels and
passages that direct hydraulic fluid
to the numerous valves
• These valves activate the
appropriate clutch pack or band
servo to smoothly shift to the
appropriate gear for each driving
situation.

20. COMPUTER CONTROLS
The computer uses sensors on the engine and
transmission to detect such things as throttle
position, vehicle speed, engine speed, engine load,
brake pedal position, etc. to control exact shift
points as well as how soft or firm the shift should
be. Once the computer receives this information, it
then sends signals to a solenoid pack inside the
transmission

21. AUTOMATIC TRANSMISSION CARS IN INDIA
Maruti celerio : 6000 rpm
Petrol, Automatic, 23.1 kmpl
Honda city : 6600rpm
Petrol, Automatic, 18 kmpl
Hyundai grand i10 : 6000rpm
Petrol, Automatic, 16.7 kmpl
Volkswagen Vento : 5250rpm
Petrol, Automatic, 14.4 kmpl

22. CONCLUSION
 Automatic transmission thus eliminates the tedious task of
constant shift of gears. Due to the addition of fuel pump,
valves etc. extra power is required to operate this systems
which is taken from the engine. Thus, this makes automatic
transmission less efficient then the manual transmission.