Audi 2003 A8 Technical Features

Service.
For internal use only
AUDI A8 ´03 - Technical Features
Self Study Programme 282
282
Complete vehicle information
The design and operation of the Audi A8 ´03 are described in the following Self Study Programmes:
Other helpful information on the Audi A8 ´03 can be found on the adjacent CD ROMs.
Electrical system CAN data bus 2
SSP 283 – 6-speed automatic gearbox 09E in the Audi A8 '03 - Part 1 SSP 284 – 6-speed automatic gearbox 09E in the Audi A8 '03 - Part 2 SSP 285 – Running gear in the Audi A8 '03 SSP 286 – New data bus systems - LIN, MOST, Bluetooth
TM
SSP 287 – Audi A8 '03 - Electrical components SSP 288 – Audi A8 '03 - Distributed functions SSP 289 – Adaptive cruise control in the Audi A8 '03 SSP 292 – Adaptive air suspension in the Audi A8 '03 SSP 293 – Audi A8 '03 - Infotainment
3
Attention Note
New
Contents
Page
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Body . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
Passenger Protection
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
Block diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16
Safety systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18
Engine, Mechanics
Technical data of V8 4.2 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
Technical data of V8 3.7 l 5V engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
Electrohydraulic torque reaction support . . . . . . . . . . . . . . . . . . . . . . . . . 32
Exhaust system. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33
Fuel tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34
Automatically controlled starting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41
Gearbox . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
Running Gear
Front axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
Rear axle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
4-level air suspension . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
Electric parking brake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
Adaptive cruise control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
Electrical System
Bus topology . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
Convenience and security electronics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Lighting system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
Heating/Air Conditioner
Design and operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
Operating principle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74
Blower unit/air routing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76
System layout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
Block diagram for front air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
Block diagram for rear air conditioner . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
The Self Study Programme contains information on design features and functions.
The Self Study Programme is not intended as a Workshop Manual. Values given are only intended to help explain the subject matter and relate to the software version applicable at the time of SSP compilation.
Use should always be made of the latest technical publications when performing maintenance and repair work.
4
Introduction
The new Audi A8 is designed to replace its predecessor of the same name which achieved a total production figure of 105,092 since its introduction in June 1994. This was the first standard saloon with aluminium body and epitomised a new philosophy in the luxury vehicle sector.
The weight-saving Audi Space Frame ASF represented a major breakthrough in terms of enhanced vehicle dynamics, whilst at the same time solving the problem of increasing weight.
Introduction
This body concept was further perfected in the Audi A2 and the design of the Audi A8 ´03 reflects the experience gained from both projects.
The aim when developing the Audi A8 ´03 was not merely to surpass its predecessor in terms of technical features and details.
Convenience/infotainment control via multimedia interface (MMI)
3.7 or 4.2 l V8 engine with intake manifold changeover function
Adaptive cruise control (ACC) with radar sensor in front bumper
Headlight with adaptive light function
Active head restraints for front seats
5
SSP282_025
As the Audi flagship, the new Audi A8 is intended to symbolise the product identity of the next Audi generation.
An uncompromising sporty character, clear­cut design, innovative technological systems and the highest possible quality level combine to provide an unforgettable driving experience.
In other words:
Audi at its proverbial best.
Automatic boot lid opening and closing function (optional)
LED-type tail lights
4-level air suspension
Electric parking brake
"Advanced Key" entry and start authorisation system
6-speed automatic gearbox 09E
6
971 2944
5051
1136
714
125
Brief outline
Body
SSP282_026
Kerb weight 1,780 kg Gross weight 2,380 kg
Turning circle 12 m Luggage compartment volume approx. 500 l
Tank capacity approx. 90 litres Drag coefficient 0.27 C
d
1629
1894
1444
2028
1615
976
7
Body
The Audi A8 ´03 sets new standards in its class by combining lightweight construction with outstanding stability. This is achieved through the use of innovative Audi Space Frame technology for the body design of the Audi A8. The technical progress reflected by the unique body concept stems from the consistent implementation of experience gained from the aluminium Audi A8 and A2 models.
SSP282_027
Based on the findings obtained from these vehicles, it was possible to further reduce the number of body components and significantly increase the level of automation in the production process as compared to the Audi A8 predecessor model.
The static torsional rigidity of the new Audi A8 body is 60 % higher than that of the previous Audi A8 body. A crucial contribution is made to the increased rigidity level by the advanced Audi Space Frame structure.
Characteristic features of the new structure:
– Large castings with numerous integrated
functions and a high degree of joint strength
– IHF* sections – optimum cross sections at
all locations, for example at side of roof frame
– Sheet metal panels with high levels of local
rigidity thanks to the use of special technologies designed to achieve differing functional cross sections and structures
*IHF = Internal high-pressure forming
8
A-pillar
The A-pillar is made of two cast shells connected by rivets and welds. The shells enclose the sill panel at the bottom and the continuous roof frame at the top.
SSP282_029
Sill panel
Use is made for the sill panel of a 3-piece extruded section. The extruded section must be replaced in the event of sill panel damage. Depending on the nature of the damage, either the entire section has to be replaced or parts of it by way of three separating sleeves.
Body
SSP282_030
9
Rear end
The rear end has been completely redeveloped. The two large central castings are the one connecting the sill panel/ longitudinal member and the C/D-pillar connecting element.
SSP282_032
The C/D-pillar connecting element (large upper casting) accommodates the suspension strut at the top and the seat belt at the front, in addition to forming the terminating side section of the roof frame.
The large upper and lower castings are interlinked by way of two straight extruded sections and form the framework for the air suspension strut holder.
SSP282_033
The sill panel/longitudinal member connecting element is the largest casting. It supports the entire rear sub-frame and links the rear longitudinal member to the sill panel. Its great rigidity is designed to protect the tank in between in the event of a rear-end collision.
Large upper castings
Extruded sections
Large lower castings
10
Body
A standard feature is an automatic closing aid, which is actuated by a Bowden cable separately from the catch. After the latch has closed, a mechanism pulls the catch downwards, overcoming the build-up of pressure occurring. On locking, a microswitch in the boot lid lock transmits a signal to the control unit to activate the automatic closing aid.
SSP282_035
The drive unit is only encased in foam and inserted between side panel and battery.
Boot lid
Electronic boot lid lock with microswitch
Foam encasing
Motor for automatic closing aid
CatchBowden
cable
11
In the event of manual boot lid actuation, the electric motor is disconnected by way of a magnetic coupling, thus permitting the boot lid to be moved by hand. On closing the boot lid, the drive is deactivated via a microswitch at the latch and the automatic closing aid activated.
Pressing the button in the driver's door or on the boot lid, or remote control actuation, effects release and motor-driven opening of the boot lid. Automatic boot lid closing can only be implemented by way of the boot lid button.
An electric motor flanged directly to the swivel joint of the right boot lid hinge opens or closes the boot lid.
SSP282_036
Automatic boot lid
As a general rule, interruption of automatic actuation always causes the boot lid to be disconnected from the drive unit and thus set to manual mode.
Hinge mechanism (open)
Boot lid control unit J605
Button in driver's door Button on boot lid Vehicle key
12
Body
Front doors
The doors are made up of a combination of aluminium panels, aluminium sections and aluminium castings. Optimised rib geometry and wall thickness in the hinge and lock mounting castings formed the basis for ideal implementation of the lightweight construction concept.
Rear doors
Large, high-strength side impact members are integrated into the door to provide even load distribution in the event of side impact.
SSP282_039
Door shell and door frame are connected at the door pre-assembly stage by means of fitted bolts to ensure the accurate assignment of both components. Window lifter frame, window lifter motor/gear mechanism, door control unit and speaker are pre-assembled on a base plate and bolted to the door subframe.
13
Seats
A new seat concept was developed for the Audi A8 ´03. The basic seat features the following standard functions:
– Electric seat length, height and angle
adjustment – Electric backrest angle adjustment – Front crash-active head restraints (refer to
Page 21)
The basic seat can additionally be fitted with
– Four-way lumbar support – Seat memory for driver and front
passenger – Electrically adjustable head restraints – Electric belt height adjusters
Extra features of sports and comfort seats:
– Electric top 1/3 backrest adjustment – Electric seat depth adjustment
Optional extras for comfort seat:
– Climate function (refer to Page 85) – and/or massage function
The massage function is implemented by way of rhythmic action of the electromechanical lumbar support, thus massaging and relaxing the back muscles.
The fixed rear seat bench versions correspond to those of the front seats, with the third head restraint being fully retractable. Electric individual seats are however only available as "Basic" and "Comfort" versions.
SSP282_116
Crash-active, electronic head restraint with 70 mm height adjustment
Thorax/pelvis side airbag
Backrest fan
Seat cushion fan
Electric seat depth adjustment – As the structure moves forwards it pulls the padding with it and so extends the seat area by 50 mm.
Backrest adjustment – The angle of the top 1/3 of the backrest can be adjusted by 15° for enhanced shoulder comfort.
Lumbar support with massage function over a length of 60 mm
14
G 256
N251
G179
G180
N153
K145
AIRBAG
OFF
N95/G85
N202
N154
N252
G 257
J533
N199
N201
G 283
G 284
N131
N200
T16
J623
J285/K75
E224
AUS
EIN
AIRBAG
J655
E24 E25
J234
N196 N198 N197
J393
J526
System layout
Passenger Protection
SSP282_068
15
The wide range of sensors permits detection not only of head-on collision and side impact, but also of rear-end collisions.
Use is made in the Audi A8 ´03 of the 8.4E+ airbag system with the aim of attaining greater occupant safety whilst reducing the impact. This was achieved, for example, by way of two­stage front airbag triggering, active front head restraints and a battery cut-off element.
K75 Airbag warning lamp K145 Airbag disabled warning lamp,
front passenger side
N95 Driver side airbag igniter N131 Airbag igniter 1, front passenger side N153 Belt tensioner igniter 1, driver side N154 Belt tensioner igniter 2,
front passenger side
N196 Rear belt tensioner igniter,
driver side
N197 Rear belt tensioner igniter,
front passenger side
N198 Rear belt tensioner igniter,
centre N199 Side airbag igniter, driver side N200 Side airbag igniter,
front passenger side N201 Rear side airbag igniter,
driver side N202 Rear side airbag igniter,
front passenger side N251 Curtain airbag igniter, driver side N252 Curtain airbag igniter,
front passenger side
T16 16-pin connector
(diagnostic connection)
Key
E24 Driver side belt switch E25 Front passenger side belt switch E224 Airbag disabling key switch,
front passenger side
G85 Steering angle sender G179 Side airbag crash sensor,
driver side (B-pillar)
G180 Side airbag crash sensor,
front passenger side (B-pillar)
G256 Rear side airbag crash sensor,
driver side
G257 Rear side airbag crash sensor,
front passenger side
G283 Front airbag crash sensor,
driver side
G284 Front airbag crash sensor,
front passenger side
J234 Airbag control unit J285 Control unit with display
in dash panel insert
J393 Convenience system central
control unit J526 Telephone/telematics control unit J533 Data bus diagnostic interface
(gateway) J623 Engine control unit J655 Battery cut-off relay
16
15
J234
J655
1
2
E224
3
G283 G284 G179
N131
F138
N202N199 N200 N201
N95
Key
E24 Driver side belt switch E25 Front passenger side belt switch E224 Airbag disabling key switch,
front passenger side
F138 Airbag coil connector/return spring
with slip ring
G179 Side airbag crash sensor,
driver side
G180 Side airbag crash sensor,
front passenger side
G256 Rear side airbag crash sensor,
driver side
G257 Rear side airbag crash sensor,
front passenger side
G283 Front airbag crash sensor,
driver side
G284 Front airbag crash sensor,
front passenger side
Block diagram
Passenger Protection
J234 Airbag control unit J655 Battery cut-off relay
N95 Driver side airbag igniter N131 Airbag igniter 1, front passenger side N153 Belt tensioner igniter 1, driver side N154 Belt tensioner igniter 2,
front passenger side N196 Rear belt tensioner igniter, driver side N197 Rear belt tensioner igniter,
front passenger side N198 Rear belt tensioner igniter, centre N199 Side airbag igniter, driver side N200 Side airbag igniter,
front passenger side N201 Rear side airbag igniter,
driver side N202 Rear side airbag igniter,
front passenger side
17
4 5 6 7
G256 G257 E24 E25
N198N251 N252 N153 N154 N196 N197
G180
N251 Curtain airbag igniter, driver side N252 Curtain airbag igniter,
front passenger side
Colour code
= Input signal
= Output signal
= Positive supply
= Earth
Additional signals
Battery A (positive)
Positive connection to starter B and alternator C
Terminal 58s
Drive system CAN (High)
Drive system CAN (Low)
Crash signal
Airbag disabled warning lamp, front passenger side K145
1
2
3
4
5
6
7
SSP282_069
18
Safety systems
2-stage front airbags
The 2-stage triggering of the front airbags provides optimum restraint in crash situations at around 30 km/h. There is a separate firing pellet for each stage in the driver's and front passenger's airbag. These ignite successively at specified time intervals.
Ring airbag
Passenger Protection
SSP282_070
A so-called "ring airbag", which inflates like a life belt, is used on the driver's side. This radial inflation method affords particular protection to drivers sitting very close to the steering wheel. The centre of the steering wheel does not move as the airbag unfolds and is inflated in the form of a ring. A rectangular fabric layer is additionally sewn to three sides of the ring. One side is left free to allow the airbag to slide over the non­moving centre section of the steering wheel.
This airbag design satisfies the requirements of the latest American legislation and involves compliance with biomechanical values for so-called "Out Of Position" (OOP) driver posture. If the driver's head or upper part of the body is very close to the steering wheel at the time of airbag unfolding (OOP), this airbag concept can prevent serious injury.
19
Front passenger's airbag deactivation
An optional feature of the Audi A8 ´03 is a new airbag disabling key switch for the front passenger's side E224. Two resistance paths are integrated into this switch to permit detection of individual faults. A fault in the key switch is indicated by flashing of the front passenger's side airbag disabled warning lamp K145 located in the centre console next to the hazard warning switch.
Front knee airbags (USA)
SSP282_081
SSP282_114
The USA version of the Audi A8 ´03 is fitted with driver's and front passenger's knee airbags as standard, thus optimising driver and front passenger movement in a crash situation.
In this way, severe impact in the knee zone is avoided. Knee airbags are required by legislation in the USA.
20
Passenger Protection
Up-front sensors
For the first time, use is made in the Audi A8 ´03 of so-called up-front sensors.
SSP282_072
Lateral acceleration sensors
Further acceleration sensors are located at the B and C-pillars.
SSP282_073
Detection of rear-end collision
Rear-end collisions are detected by way of a sensor in the airbag control unit J234 and a plausibility function involving the driver's and front passenger's front airbag crash sensors G283 and G284.
These take the form of two additional front­end acceleration sensors on the right and left beneath the corresponding headlight.
C-pillar sensor B-pillar sensor
21
Active head restraints
The front seats of the Audi A8 ´03 are provided with active head restraints. With this system, the head restraints move forwards in the event of a rear-end collision to shorten the distance between head and restraint.
SSP282_082
The danger of cervical vertebrae injury is greatly diminished by reducing the relative acceleration between shoulder and head. In head-on collision situations, the mechanics of centrifugal weight are neutralised.
Belt tensioners
Five belt tensioners are fitted as standard. There is no centre belt tensioner if the rear seats are electrically adjustable.
22
Passenger Protection
15
30
+
-
31
J644
J655
4
3
B
1
2
A
Terminal Pin Input/output Description
30, battery A Input
(screw connection)
U
bat.
term. 30/battery
87 B Output
(screw connection)
Output
Terminal 15 1 Input
(plug connection)
Positive power supply,
interruptible
Vehicle earth 2 Input
(plug connection)
Earth from
airbag control unit J234
Crash signal 3 Input
(plug connection)
Crash signal from
airbag control unit J234
Diagnosis 4 Input
(plug connection)
Diagnostic wire from
airbag control unit J234
Battery cut-off relay J655
The battery cut-off relay is a battery isolating element designed to disconnect starter and alternator power from the electrical system in the event of a crash.
Block diagram
J644 Energy management control unit J655 Battery cut-off relay
SSP282_076
23
Fitting location
The battery cut-off relay is located in front of the battery.
Triggering
The airbag control unit J234 provides the battery cut-off element with the triggering command via a discrete wire. Triggering of this element by the airbag control unit causes a white panel to appear in the element window instead of a copper coil. Following isolation, the battery cut-off element can be manually reset by way of the yellow knob.
Control element test
The control element test in the airbag control unit also triggers the battery cut-off relay. It should be ensured that the relay is manually reset, as otherwise the battery cannot be charged.
SSP282_079
SSP282_077
SSP282_083
Reset knob
Window
24
Engine, Mechanics
2000
4000
6000
406080
1
60
4
0
260
280
300
320
340
360
380
400
420
440
460
Technical data
V8 4.2 l 5V engine
Engine code letters: BFM
Capacity:
3
Bore: 84.5 mm
Stroke: 93.0 mm
Compression ratio: 11 : 1
Power: 246 kW (335 hp)
at 6,500 rpm
Torque: 430 Nm at 3,500 rpm
Camshaft adjustment range: 22° CS advance
Valves: 5 per cylinder
Engine management: ME7.1.1
Emission standard: EU 4
Firing order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Capacities: 7.5 l engine oil (incl. filter)
Consumption: Urban: 17.5 - 17.6 l/100 km
Non-urban: 8.7 - 8.8 l/100 km Average: 11.9 - 12.0 l/100 km
Acceleration 0 - 100 km/h: 0 - 80 km/h – 4.8 s
0 - 100 km/h – 6.3 s
Fuel: Premium Plus Unleaded
98/95 RON
CS = Crankshaft
SSP282_002
SSP282_012
Engine speed [rpm]
Power [kW]
Torque [Nm]
4,172 cm
25
260
280
300
320
340
360
380
400
420
440
460
240
V8 3.7 l 5V engine
Engine code letters: BFL
Capacity:
3
Bore: 84.5 mm
Stroke: 82.4 mm
Compression ratio: 11 : 1
Power: 206 kW (280 hp)
at 6,000 rpm
Torque: 360 Nm at 3,750 rpm
Camshaft adjustment range: 13° CS advance
Valves: 5 per cylinder
Engine management: ME7.1.1
Emission standard: EU 4
Firing order: 1 - 5 - 4 - 8 - 6 - 3 - 7 - 2
Capacities: 7.5 l engine oil (incl. filter)
Consumption: Urban: 17.1 - 17.3 l/100 km
Non-urban: 8.6 - 8.8 l/100 km Average: 11.7 - 11.9 l/100 km
Acceleration 0 - 100 km/h: 0 - 80 km/h – 5.6 s
0 - 100 km/h – 7.3 s
Fuel: Premium Plus Unleaded 98/95 RON
SSP282_001
SSP282_011
Engine speed [rpm]
Power [kW]
Torque [Nm]
3,697 cm
26
Engine, Mechanics
V8 5V 3.7 l/4.2 l engine
The 3.7 l and 4.2 l V8 engines were adopted from the predecessor model with certain modifications.
These modifications relate to the intake and exhaust systems and are described in the following.
Design and operation are described in SSP 217.
Variable-intake manifold in 4.2 l engine
This takes the form of a 2-stage variable-intake manifold made of a die-cast magnesium alloy, bonded and bolted together in four sections.
The two-stage design permits the use of two intake paths with large cross section.
The intake manifold must be replaced as a complete unit when performing repairs.
SSP282_013
27
– Long intake path, 705 mm – Changeover flap closed for high torque
Each of the two splined shafts is fitted with four flaps per cylinder bank. The shape of the rubber-encased flaps ensures unimpeded air flow in the torque position and reliable power position sealing of the duct. This is a prerequisite for utilisation of the gas-dynamic resonance effects. In the power position, the backs of the flaps take on the shape of the duct wall, thus allowing low-resistance intake air flow into the cylinders.
Mechanical couplings provide a link with the vacuum units for adjustment of the two shafts and thus the intake manifold flaps.
– Short intake path, 322 mm – Changeover flap open for high power
with high air throughput
Changeover from long to short at 4,480 rpm Changeover from short to long at 4,320 rpm
SSP282_014
SSP282_016
SSP282_015
28
Engine, Mechanics
Variable-intake manifold in 3.7 l engine
Operation of the 3-stage variable-intake manifold is described in SSP 217.
SSP282_017
This is the same 3-stage variable-intake manifold as previously fitted in the V8 engine.
Due to the piston stroke of only 82.4 mm, three resonance tube lengths are required to achieve resonance effects in the lower engine speed range.
Changeover points:
– Long to short
at 3,280 rpm
– Short to long
at 3,120 rpm
– Short to shorter
at 5,120 rpm
– Shorter to short
at 4,920 rpm
Changeover flap, stage 3
From electronic throttle
Throttle valve
Intake air (inlet)
Changeover flap, stage 2 (open)
Resonance tube, cyl. 5 (inlet end)
Vacuum unit Changeover flap, stage 2
Vacuum unit Changeover flap, stage 3
Injector mounts
29
Air cleaner
A round filter is employed instead of a flat filter to achieve a larger filter surface area for more air throughput in view of the different amount of space available.
Furthermore, an additional intake air flap in the air cleaner is opened as a function of load at engine speeds as of 3,000 rpm to attain the large volume of air required at full throttle. This flap enables additional air to be drawn in from the engine compartment and reduces the air velocity in the air cleaner.
SSP282_018
SSP282_019
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