Self-Study Programme 414 4 motion with four wheel drive coupling generation IV.pdf

Service Training

Self-study Programme 414

4MOTION with Four-wheel Drive Coupling

Generation IV

Design and Function

Volkswagen has been using Haldex couplings for its

4MOTION four-wheel drive system since 1998. The

new generation of four-wheel drive coupling is being

used for the first time in the Tiguan.

The new four-wheel drive coupling exclusively uses

electronic control so that any amount of torque can be

built up at any time regardless of slip. The distribution

of the drive power to the axles is variable and

depends on the driving situation. The new four-wheel

coupling in the 4MOTION system can thus react

ideally and extremely fast to all driving situations.

S414_002

You will find information on the previous generations of the Haldex couplings in self-study programmes:

●

SSP206 – Four-Wheel Drive with Haldex Coupling

SSP333 – 4MOTION with Haldex Coupling, year of models 2004

●

NEW

Important

Note

The self-study programme shows the design

and function of new developments.

The contents will not be updated.

For current testing, adjustment and repair

instructions, refer to the relevant

service literature.

Contents

In Brief . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4

Recap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

The new Generation IV four-wheel coupling . . . . . . . . . . . . . . . . . . . . . . . . . 5

4MOTION Drive Train . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6

Overview of design . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Bevel gear system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Propshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Rear-axle differential . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Four-wheel drive coupling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Four-wheel Drive Coupling in Detail . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Mechanical assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Electrohydraulic assembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Four-wheel drive control unit J492 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Regulation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Driving situations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

System overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Functional Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .23

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Diagnosis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Test Yourself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

In Brief

Recap

In 1998, the 4MOTION drive system replaced the Synchro four-wheel drive system at Volkswagen. Whilst the

Synchro system used a Visco coupling, 4MOTION used a four-wheel drive coupling from Haldex for the first time.

The four-wheel drive can be controlled electronically using this electrohydraulic clutch plate. In addition to slip, the

control unit can take driving dynamic states like cornering, speed, deceleration and acceleration into account.

First generation Haldex coupling

Haldex coupling from model year 2004,

generation II

S414_003

S414_004

The third-generation Haldex coupling was not used by Volkswagen.

How the Haldex coupling works

On the first two generations of the Haldex couplings,

a speed difference between the front and rear axles

was used to create a pumping effect that builds up

working oil pressure using a lifting plate, actuating

rollers and two parallel lifting pistons. This pressure

pushes the clutch plate set together via a working

piston. The level of the pressure applied determines

how much drive torque is transferred.

Suction and pressure valves, an electronically

controlled valve and a control unit regulate the

pressure on the clutch plates.

Fourth-generation four-wheel drive coupling

In principle, power is transmitted via the clutch plate set on the fourth generation of the four-wheel drive coupling

in the same way as the previous Haldex models. One new feature is the pressure being built up with an electric

pump. The four-wheel drive control unit J492 determines the torque to be transferred by controlling the coupling

opening control valve N373. Speed differences between the front and rear axle are no longer required to activate

the four-wheel drive coupling.

Technical features

Electrohydraulically controlled clutch plate

●

Integrated in the rear axle drive

●

Simplified hydraulic system

●

Optimised, demand-regulated pump control

●

S414_005

Advantages

Coupling control not dependent on driving

situation

●

Fast moment build-up by means of pre-control

●

Permanent rear-axle drive capacity

●

Fully compatible with traction control systems

(e.g. ESP, ABS)

●

Plik z chomika:

Inne pliki z tego folderu:

Inne foldery tego chomika: