722.9 Automatic Transmission

8/19/2019 722.9 Automatic Transmission

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722.9 Automatic Transmission722.9 Automatic Transmission

Tech 331, 722.9 (F,hayward),1/27/04



ObjectivesObjectives

? To know the advantages and Features of the

722.9 transmission

? To identify new components

? To understand maintenance concerns

? To know location / function of major components

? To explain shift members

? To explain electronics

2



Features 722.9Features 722.9

h Electronically controlled 7-speed

h Seven forward and two reverse gears

h Fully integrated transmission control unit (Flash capable)

h Torque converter operates in open or slip mode in all sevenforward gears

h Gear ratios are achieved with four multi disc brakes and threemulti disc clutches (no free-wheeling units)

h 2 simple and 1 ravigneaux gear set

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Advantages Advantages

?

Improved shift comfort/driving pleasure

q Quicker shifts 0.1 – 2.5 seconds

q 37 to 74 mph times shortened by between 23% and 28%

? Reduce fuel consumption (up to 4%)

? Reduce maintenance cost

h Increased service life and reliability

h Flexible adaptation to vehicle and engine

h Driver can choose between “S” and “C” mode

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Transmission DesignationTransmission Designation

Transmission722. 9 01

Version, e.g. matching to the respective engine

Sales designation

Automatic transmission for passenger cars

Sales Designation

W 7 A 700

Max. input torque in NM

Version (internal)

Number of forward gears

Hydraulic torque converter

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Transmission Fluid Transmission Fluid

? The 722.9 transmission requires a newly developed transmission

fluid. MB part number A001 989 45 03

q Higher friction constancy

q

Higher thermal stabilityq Improved temperature behavior

q Lifetime fill

?

Can be used in 722.3 / .4 / .5 / .6

? Must be used in 722.9

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Major Components (7 GMajor Components (7 G--Tronic)Tronic)

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Major Components Legend Major Components Legend

1. Park pawl gear 2. Turbine wheel

3. Stator

4. Impeller

5. Transmission housing ventilation

6. Oil pump7. B1 multi-disk brake8. K1 multi-disk clutch

9. Ravigneaux gear set

10. B3 multi-disk brake

11. K2 multi-disk clutch

12a. Front simple planetary gear set12b. Rear simple planetary gear set

13. BR multi-disk brake

14. K3 multi-disk clutch

15. B2 multi-disk brake

16. Torque converter lockup clutch17. Torque converter housing

18. Exciter ring for torque measurement19. Ring magnet for torque measurement

20. Ring magnet for torque measurement

21. Electro hydraulic control unit

22. Range selector lever

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Transmission Housing Transmission Housing

• Magnesium housing (lighter weight) requires aluminum boltsany aluminum bolt must be replaced if removed!

• No power tools

• Adhere to angle torques

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Ravigneaux Gear Set Ravigneaux Gear Set

1. Short planetary gear 2. Long planetary gear

3. Sun gear

4. Planetary gear carrier

Advantages of ravigneaux gear set

• Shifting under load

• Production of several gear ratios

• Constant engagement of gearing

• Easier reversal of rotational direction

• High efficiency

• Compact construction

• Combines 2 simple planetary gear sets

into one unit

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Multi Multi --disk Clutch/Brakedisk Clutch/Brake

• Transferable power of multi-disk clutch increased

• Friction disks of K1, K2 and K3 now have

single-sided friction disks

• Cost advantage

• Less installation space required

• Higher load capability

• Lower mass

1. Friction lining on one side of metal carrier

A. Metal carrier outer diskB. Metal carrier inner disk

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Fully Integrated TransmissionFully Integrated Transmission

Control Control

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Fully Integrated TransmissionFully Integrated Transmission

Control Legend Control Legend

11 Plug connection

21b Valve body

21c Intermediate panel

21d Shift housing

31 Float 132 Float 2

Y3/8 Electric control module

Y3/8n1 Turbine rpm sensor

Y3/8n2 Internal rpm sensor

Y3/8n3 Output rpm sensor

Y3/8n4 Transmission controlunit

Y3/8s1 Selection range sensor

Y3/8y1 Working pressure control solenoid valveY3/8y2 K1 clutch control solenoid valve

Y3/8y3 K2 clutch control solenoid valve

Y3/8y4 K3 clutch control solenoid valve

Y3/8y5 B1 brake control solenoid valveY3/8y6 B2 brake control solenoid valve

Y3/8y7 B3 brake control solenoid valveY3/8y8 Torque converter lockup clutch

control solenoid valve

13



Electronic Transmission ControlElectronic Transmission Control

Unit InputsUnit Inputs

Monitors and shifts transmission based on:

• Vehicle speed

• Vehicle load

• Accelerator position

• Selector lever position

• Electronic selector lever module (N15/5)

• Transmission condition (aging)

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Internal inputs effecting solenoid valves

• Turbine rpm sensor (active)

• Internal rpm sensor (active)

• Output rpm sensor (hall)

• Transmission oil temperature sensor


Unit InputsUnit Inputs

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Unit Unit

• Mounted directly on the hydraulic control unit

• Married to vehicle

– ETC unit calibrated to hydraulic controlunit on flow bench

• Information received over CAN with ME

– Engine rpm, coolant temperature,

accelerator position, engine load

– ESP signals

– Cruise control signals

• Information received from ETC

– Position of selector range valve

– Transmission oil temperature

– Transmission internal revolutions

– Transmission output rpm 16




Unit FunctionsUnit Functions

From data received Transmission control unit

calculates

• Driver and vehicle specific shift points

• Hydraulic pressures

• Torque converter lockup clutch

• Corrects for atmospheric pressure, shifting and

pressure

• Driver actions; accelerator movement, manualtouch frequency, longitudinal and lateralacceleration

• Software can be updated, referred to as flashing,

carried out using SDS

17



Speed Sensor LocationsSpeed Sensor Locations

Y3/8n1 Turbine rpm sensor

Y3/8n2 Internal rpm sensor Y3/8n3 Output rpm sensor

1. Ring magnet

2. Cylinder flange withintegrated ring magnet

3. Exciter ring

4a. Park pawl gear

• Turbine speed sensor monitorsrotational speed of internalravigneaux gear

• Internal speed sensor measures

rotational speed front planetary

gear

• Output speed sensor measures

transmission output speed park

pawl

• Output speed sensor increases

reaction time

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Shift ProgramShift Program

Basic shift program can be influenced using selector button

on the electronic selector lever control module

• Driver can choose transmission modes, “C” (comfort) or “S” (sport)

• Each mode has different shift strategies

• Transmission mode “S” (firmer faster shift) as opposed to mode “C”engine rpm level raised

• Switch position transmitted by electronic selector module over CAN-Cto ETC

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Shifting ProcessShifting Process

• ETC controls solenoid valves electronically

• Valves sit in hydraulic shift plate

• Shift plate implements hydraulic function

• ETC precisely adjusts pressure during shift phase, which leads to increasein shift quality

• Main function of ETC is to evaluate inputs relevant to transmission

function and actuate eight hydraulic valves, which set working pressure

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Solenoid ValvesSolenoid Valves

Internal output signal or actuation of

control solenoid valves

• Torque converter lockup clutch

valve (Y3/8y8) normally closed in

default no pressure

• Working pressure valve (Y3/8y1)normally open in default allows

pressure

• K2 clutch valve (Y3/8y3)

normally open in default allowspressure

• B2 brake valve (Y3/8y6)

normally closed in default no

pressure

Y3/8y8 – Torque converter lockup clutch valve

Y3/8y1 – Working pressure valveY3/8y3 – K2 clutch valveY3/8y6 – B2 brake valve

22



Solenoid ValvesSolenoid Valves

Internal output signal or actuation of

control solenoid valves


normally open in default allows

pressure


normally open in default allows

pressure


normally closed in default no

pressure


normally open in default allowspressure

Y3/8y2 – K1 clutch valve

Y3/8y5 – B1 brake valve

Y3/8y7 – B3 brake valve

Y3/8y4 – K3 clutch valve23



722.9722.9

Down Shifting Down Shifting

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Shift Chart Shift Chart

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Documents

722.9 Automatic Transmission