AUTOMOBILE PRESENTATION

AUTOMATIC TRANSMISSION

AUTOMOBILE PRESENTATION

AUTOMATIC TRANSMISSION

Submitted By:

Ashu Airan

(2011ume1495)

Avinash Misra

(2011ume1496)

Chetram Meena

(2011ume1497)

Deepa Ram Suthar

(2011ume1498)

INTRODUCTION

• Device which changes gear ratios automatically

• Deliver maximum efficiency

• Difference between automatic and manual transmission

• Easier to drive because they do not have a clutch pedal or

gearshift lever

• There are two type of automatic transmissions

CLASSIFICATION

Automatic transmissions

using planetary gears

Continuously variable transmission(cvt)

AUTOMATIC TRANSMISSIONS USING PLANETARY GEARS

Components :

• Planetary Gear System

• Torque Converter

• Hydraulic System

• Governor

• Computer Controls

PLANETARY GEAR SYSTEM (SIDE VIEW)

HOW PLANETARY GEARS WORK

Input Output Stationary Calculation Gear Ratio

A Sun (S) Planet Carrier (C) Ring (R) 1 + R/S 3.4:1

B Planet Carrier (C) Ring (R) Sun (S) 1 / (1 + S/R) 0.71:1

C Sun (S) Ring (R) Planet Carrier (C) -R/S -2.4:1

Gear Input Output Fixed Gear Ratio

1st 30-tooth sun 72-tooth ring Planet carrier 2.4:1

2nd

30-tooth sun Planet carrier 36-tooth sun 2.2:1

Planet carrier 72-tooth ring 36-tooth sun 0.67:1

Total 2nd 1.47:1

3rd30- and 36-tooth

suns72-tooth ring 1.0:1

OD Planet carrier 72-tooth ring 36-tooth sun 0.67:1

Reverse 36-tooth sun 72-tooth ring Planet carrier -2.0:1

• Power transfer can only take place when one of the members is held at rest or if two of the members are locked.

TORQUE CONVERTOR

• Takes the place of the clutch Found on standard shift vehicles

• Large doughnut shaped device that is mounted Between the engine and the transmission • It uses oil or transmission fluid to transmit power• Three internal elements that work together to transmit power to the transmission.

TORQUE CONVERTOR

THE HYDRAULIC SYSTEM

• Complex maze of passages and tubes that sends transmission fluid under under pressure to all parts of the transmission

and torque converter. • Transmission fluid serves in shift control, general lubrication and

transmission cooling.• Keeps the transmission at normal operating temperature• Oil pump• Valve body• Shift valves• Bands

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.

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.

Shift Valves

• Supply hydraulic pressure to the clutches and bands to engage each gear• Determines when to shift from one gear to the next• The 1 to 2 shift valves determines

when to shift from first to second gear.

BAND

• A band is a steel strap with

friction material bonded to the

inside surface.

GOVERNER

• Provides the inputs that tell the

transmission when to shift.

• Connected to the output shaft and

regulates hydraulic pressure based on

vehicle speed.

COMPUTER CONTROLLS

• Detect such things as throttle position, vehicle speed, engine speed, engine load etc. To control exact shift points .

• Downshift automatically when going downhill, to control speed and reduce wear on the brakes.

• Up shift when braking on a slippery surface to reduce the braking torque applied by the engine.

• Inhibit the up shift when going into a turn on a winding road.

CONCLUSION

Automatic transmissions contain mechanical systems, hydraulic systems, electrical systems and computer controls, all working together in perfect harmony