advance transmission technology lecture 1 22 jan 2013

8/9/2019 Advance Transmission Technology Lecture 1 22 Jan 2013

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LECTURE 1

OVERVIEW OF THE AUTOMATIC

TRANSMISSION PRINCIPLE

ADVANCE TRANSMISSION

TECHNOLOGY


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HISTORY AND A/T PRINCIPLEDefinition

• An automobile gearbox that can change gear ratios

automatically as the car moves, thus freeing the

driver from having to shift gears manually

• Oldsmobile's 1940 models was first vehicles with

fully automatic transmission which called

Hydramatic drive. It provided true clutchless driving.• Hydramatic designed to combine hydraulic operation

of planetary gearbox with a fluid coupling instead of

a friction clutch

History and Improvement


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2.Used the torque converter clutch (TCC)

•.applied in early 1980s with the advent of enginecomputers.

•.Involved a solenoid-controlled clutch inside the

torque converter, which would lock its input to its

output when activated.

•. To eliminate the ''drag'' or inefficiency caused by

the fluid in the converter when operating at high

speeds.


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3. Used computer control shift patterns and gear

ratios to turn on and off the solenoids

•remove almost all of the control logic from the

valve body, and place it in the hands of the

engine computer.

• by using the ECU controlled solenoids instead of

spring-loaded valves in the valve body, providesthe precise control of shift points and shift

quality.


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In Europe automatic transmissions have never beenspecifically popular and even today.

This is partly because automatic gearboxes are less efficientthan their manual counterparts, giving rise to a noticeabledeterioration in vehicle performance when coupled with thesmall capacity engines that are common in Europe.

Another factor is that European roads tend to be less wellgraded than those of North America, and so the additionaldriver control afforded by a manual gearbox is often to be valued.

Automatic transmissions are costly and are generallyavailable as an extra-cost option, which often deterspotential purchasers.


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Basic Parts and Operation

Torque Converter

• Fits between engine and transmission to provide a

torque boost at low speeds and during acceleration.

• This allows the engine and transmission to be

mated full-time without the need of clutch.

• Provides a small amount of continuously variable

power transmission between the fixed gear ratios.


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Valve body

• Centre of the system

• Receives pressurized fluid from main pump that

connected to transmission's input shat.

• The fluid than regulated and runs a network ofspring-loaded valves, check balls and servo pistons.


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• Use the pump pressure and pressure from a

centrifugal governor on the output side (as well as

hydraulic signals from the range selector valves and

the ''throttle valve'' or ''modulator'') to control which

ratio is selected on the gearset.

• as the car and engine change speed, the difference

between the pressures changes, causing different

sets of valves to open and close.



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Epicyclic gearing (Planetary gearset)

• The main gears in most hydraulic automatics are a

compound planetary set.

• Gear ratios are selected by a system of bands and

clutches, which are actuated by hydraulic servos

that controlled by valve body.


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Advantages

•

No need for the driver to depress a clutch to changegear.

• Gears change automatically dependent upon the

speed of travel.

• Use of the sports mode, where applicable, allows

lower gears to hold until higher revs are reached.

• Winter mode, where applicable, may lock out first

gear to reduce the risk of wheelspin in adverse

weather conditions.

• Easier to move off, especially on inclines, and easier

control in traffic due to the inherent creep facility.


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Advantages

•

The ability to manually select lower gears whenapproaching hills or for engine braking on descents.

• Less wear and tear on the gearbox, transmission and

vehicle body due to automatic gear changes.

• Smoother ride, even when reversing.• Rocking back and forth when stuck in mud or snow

is quicker and easier by using the selector lever and

no clutch.

• Vehicle will not roll backwards when in “drive”

position.


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Disadvantages

• May need to have a transmission oil cooler fitted,

especially when towing.

• Automatics may have a lower manufacturer’s towing

limit than the equivalent manual version.

•

May cost more to purchase an automatic than asimilar manual car.

• Uses more fuel per kilometer/mile.

• Acceleration is slower than a manual due to delay of

the kick down facility.• May need more regular servicing.

• Not many diesel versions around.


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VEHICLE OPERATION


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Selector Lever Pattern

P - Parking

• Each element does not operate at all. Therefore, the

engine output is not transmitted to the output shaft.

• The output shaft is completely locked by mechanicalmeans. Therefore, the car does not move in forward

or reverse direction. The engine can be started.

R - Reverse

• The car moves in reverse direction. The engine

cannot be started.


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N – Neutral

• The engine output is not transmitted to the output

shaft as in the case of "P". The engine can be started.

D – Drive

• Automatically shifts ups and down between forward

4 speeds depend on throttle opening and vehicle

speed. However, only forward 3 speeds are selected

when the overdrive control switch is OFF.

• When vehicle is stopped, shifting is made to the 2nd

gear to minimize creep and vibration.


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2 – Second

• Automatically shifts between 1st and 2nd gears.

This means no upshift to 3rd gear occurs

• For engine braking

L – lock up (1st)

• Does not shift up the gear from 1st to 2nd or 3rd.

This enables what is called "1st gear holding".

Driving-off is always performed in 1st gear.

• For stronger engine braking


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O/D – Overdrive

•Shifted automatically bysimply easing up on the

accelerator without

depressing the clutch pedal.

• Electrically operated solenoid

would deactivate the unit via

a switch


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PWR or NORMAL

• For selecting a driving

pattern suitable to existing

driving conditions


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Shift Pattern Chart

Vehicle in state 1

• When accelerator pedal not pressed, 2nd gear is held.

• When accelerator pedal is pressed, downshifting is made to the

1st gear to cause prompt acceleration.


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Vehicle in state 2

• The vehicle is run steadily at 4th-gear speed on the flat road.

Shift Pattern Chart


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Vehicle in state 3

• Vehicle is climbing uphill, driver must press the accelerator

pedal positively.• Traveling from 2 to 3, vehicle state goes across the 4 - 3 (D4)

downshift line. Therefore, the 3rd gear is selected.

Shift Pattern Chart


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Vehicle in state 4

• Vehicle enters flat road after the uphill, driver returns the

accelerator pedal to the idle position.• Traveling from 3 to 4, vehicle state goes across the 3- 4 (D4)

upshift line. Therefore, the 4th gear is selected.

Shift Pattern Chart


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Vehicle in state 5

• Vehicle exits the flat road and runs to the steep uphill road.

Driver must press the accelerator pedal.• Traveling from 4 to 5, vehicle state goes across the 4 - 3 (D4)

and 3 - 2 (D) downshift lines. Therefore, downshifting to the

2nd gear is performed.

Shift Pattern Chart


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Vehicle in state 6

• After reaching the crest of hill, vehicle enters flat road. Driver

returns the accelerator pedal to idle position.• Traveling from 5 to 6, vehicle state goes across the 2 - 3 (D)

upshifts line. The 3rd gear is selected.

Shift Pattern Chart


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Vehicle in state 7

• Vehicle enters downhill road, driver releases the acceleration

pedal. Also, turns off the OD switch.• 7 is located on the left side of the 4 - 3 (D3) downshift line,

downshifting to the 3rd gear is performed regardless of the

throttle valve opening.

Shift Pattern Chart


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Vehicle in state 8

• Vehicle runs on the steep downhill road. Driver turns the

selector lever from "D" to "2"nd range.• Since position is located on the left side of the 3 - 2 (2, L)

downshift line, downshifting to the 2nd gear is performed

regardless of the throttle valve opening

Shift Pattern Chart


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Vehicle in state 9

• While running on the downhill road, the driver turns the

selector lever from "2" to "L" range.• Vehicle state goes across the 2 ~ 1 (L) downshift line when

speed decreases from 50 to 40, downshifting is made from the

2nd gear to the 1st gear.

Shift Pattern Chart


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OPERATION OF

HYDRAULICFLOW IN VALVE

BODY

$or%ue converter

F t l t h R l t h

Lo&-reverse 'ra(e

d l h

)ic(do&n servo

F t l t h R l t h d l h


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Shift controlvalve

N-D controlvalve

Pressure controlvalve

Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve

Damper clutchcontrol valve

Damper clutchcontrol solenoid valve

OFF

OFF

ON

OFFPressure controlsolenoid valve

End clutchvalve

1- shiftvalve

-!"#-!shift valve

Front clutch Rea r c lutch End clutch

Shift controlsolenoid valve *

Shift controlsolenoid valve +

P R N D L

$o lu'ricationfront

$o lu'ricationrear

Rear clutche,haust valve

$ransmissionontrol .nit




P R N D L

Park Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve

OFF

ON

OFF

1- shiftvalve

-!"#-!shift valve

Front clutch Rea r c lutch End clutch



P R N D L






P R N D L

$or%ue converter

Front c lutch Rea r c lutch

Lo&-reverse 'ra(e

E d l t h

)ic(do&n servo


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Neutral Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve


Damper clutchcontrol solenoid valve

OFF

OFF

ON

OFF

Pressure controlsolenoid valve

End clutchvalve

1- shiftvalve

-!"#-!shift valve

Front c lutch Rea r c lutch End clutch



P R N D L

$o lu'ricationfront

$o lu'ricationrear






P R N D L

$or%ue converter


Lo&-reverse 'ra(e

E d l t h

)ic(do&n servo


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Drive !to" Position#

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve


Damper clutchcontrol solenoid

valve

OFF

OFF

ON

/0 dut2


End clutchvalve

1- shiftvalve

-!"#-!shift valve




P R N D L

$o lu'ricationfront

$o lu'ricationrear






P R N D L

$or%ue converter


Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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Drive $st Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

ON

ON

33 dut2


End clutchvalve

1- shiftvalve

-!"#-!shift valve




P R N D L

$o lu'ricationfront

$o lu'ricationrear






P R N D L

$or%ue converter


Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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Drive %n& Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

OFF

ON

OFF


End clutchvalve

1- shiftvalve

-!"#-!shift valve




P R N D L

$o lu'ricationfront

$o lu'ricationrear




$ransmission

ontrol .nit


P R N D L

$or%ue converter


Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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Drive 'r& Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

OFF

OFF

OFF


End clutchvalve

1- shiftvalve

-!"#-!shift valve

o t c utc ea c utc End clutch



P R N D L

$o lu'ricationfront

$o lu'ricationrear




$ransmission

ontrol .nit


P R N D L

$or%ue converter

Front clutch Rea r c lutch

Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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Drive (t) Position

Shift controlvalve

N-D controlvalve


Manualvalve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

ON

OFF

OFF


End clutchvalve

1- shiftvalve

-!"#-!shift valve

End clutch



P R N D L

$o lu'ricationfront

$o lu'ricationrear




$ransmission

ontrol .nit


P R N D L

$or%ue converter


Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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Reverse Position

Shift controlvalve

N-D controlvalve


Manual valve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

OFF

ON

OFF Pressure controlsolenoid valve

End clutchvalve

1- shiftvalve

-!"#-!shift valve

End clutch



P R N D L

$o lu'ricationfront

$o lu'ricationrear




$ransmission

ontrol .nit


P R N D L

$or%ue converter


Lo&-reverse 'ra(e

End clutch

)ic(do&n servo


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*L+ Position

Shift controlvalve

N-D controlvalve


Manual valve

N-R controlvalve

Line relief valve

Oil filter

OilPump

Regulator valve

Reducingvalve



valve

OFF

ON

ON

Dut2control


End clutchvalve

1- shiftvalve

-!"#-!shift valve



P R N D L

$o lu'ricationfront

$o lu'ricationrear




$ransmission

ontrol .nit


P R N D L


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ASSIGNMENT 1:

LIST AND EXPLAIN ALL THE

COMPONENTS IN AUTOMATIC

TRANSMISSION / TRANSAXLEGEARBOX

advance transmission technology lecture 1 22 jan 2013

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