transmission AUDI S4 1998 B5 / 1.G Engine Manual

3
This Self-study Programme provides you with information
regarding design and function.
The Self-study Programme is not a Workshop Manual!
Please refer to the Service Literature for all the relevant
maintenance and repair instructions.
Page
Engine .........................................................
Technical data, crankshaft, cylinder head,
camshaft timing, cooling circuit, engine
lubrication, overview of components, air ducting,
charging, exhaust system, pneumatically
controlled systems, charge pressure control, air
divert control in overrun, ACF system, crankcase
breather
4
Motronic ME 7.1 ..........................................
Subfunctions, system overview
31
Subsystems of the Motronic .....................
Torque-oriented engine management, torque-
oriented functional structure, Electronic throttle,
exhaust gas temperature control
33
Sensors .......................................................
Additional sensors of the Motronic
49
Auxiliary signals/interfaces ...................... 57
Functional diagram ..................................... 62
Self-diagnosis .............................................
Vehicle diagnosis, test and information system
VAS 5051, test box V.A.G 1598/31
64
Transmission ..............................................
Self-adjusting clutch, gearbox
66
Contents
Important!/Note!
New!

66
Power Transmission
Self-adjusting clutch
Advantages:
• Constant clutch releasing loads throughout
the service life of the clutch plate.
• Greater wear reserve of the clutch plate. For the biturbo engines, Audi is
using an SAC clutch pressure plate
with a wear compensation feature
for the first time.
„
SAC
“ stands for
S
elf-
A
djusting
C
lutch.
SSP 198/42

Auxiliary spring
Adjusting ringSensor plate spring
Main diaphragm spring
Compression spring
Housing cover

68
Power Transmission
Function of SAC clutch
Compared to a conventional clutch, the
following parts are new or modified:
• Sensor plate spring
• Adjusting ring with ramps (wedges) and
compression springs
• Housing cover with ramp indentations and
guides for the compression springs
• Stop for release travel (integrated in the
housing cover)
• Auxiliary spring (riveted to the housing
cover)The
stop for release travel
limits the
travel of the release bearing and
prevents unintentional adjustment of
the adjusting ring.
The
auxiliary spring
counteracts the
main plate spring as of a defined
travel distance and ensures an even
force curve during clutch engagement
and disengagement.
SSP 198/70

Housing cover with auxiliary spring
and s
top for release travel
Main diaphragm spring
Pressure plate
Auxiliary spring
(riveted on)
Sensor plate spring
Adjusting ring with
compression springs

70
Power transmission
Clutch disengagement process
The force of the sensor plate spring
counteracts that of the main diaphragm spring
and is rated such that the main diaphragm
spring is pressed against the adjusting ring
under normal releasing load.
If the force of the main diaphragm spring (also
refer to load diagram) is greater than that of
the sensor plate spring, the main plate spring
will not come into contact with the adjusting
ring.
The compression springs rotate the adjusting
ring along the ramps in the housing cover.
In this way, lining wear is compensated and
the forces are again equalised.

SSP 198/74

Main diaphragm spring
Sensor plate springHousing cover
Adjusting ring with ramps
Compress. spring
Compression spring
Main
diaphragm
spring
mounting
Ramp (wedge)
after wear
as new