The Phaeton Adaptive Cruise Control Design and Function

The Phaeton Adaptive Cruise ControlDesign and Function

Self-Study ProgramCourse Number 898303

Volkswagen of America, Inc.Service TrainingPrinted in U.S.A.Printed 08/2003Course Number 898303

©2003 Volkswagen of America, Inc.

All rights reserved. All information containedin this manual is based on the latestinformation available at the time of printingand is subject to the copyright and otherintellectual property rights of Volkswagen ofAmerica, Inc., its affiliated companies and itslicensors. All rights are reserved to makechanges at any time without notice. No partof this document may be reproduced,stored in a retrieval system, or transmittedin any form or by any means, electronic,mechanical, photocopying, recording orotherwise, nor may these materials bemodified or reposted to other sites withoutthe prior expressed written permission ofthe publisher.

All requests for permission to copy andredistribute information should be referredto Volkswagen of America, Inc.

Always check Technical Bulletins and theVolkswagen Worldwide Repair InformationSystem for information that may supersedeany information included in this booklet.

Trademarks: All brand names and productnames used in this manual are trade names,service marks, trademarks, or registeredtrademarks; and are the property of theirrespective owners.

i

Table of Contents

The Self-Study Program provides you with informationregarding designs and functions.

The Self-Study Program is not a Repair Manual.

For maintenance and repair work, always refer to thecurrent technical literature.

Important/Note!

New!

Introduction ...............................................................................1

The Phaeton Adaptive Cruise Control System,ACC Component Locations, ACC Operation,Functional Limits, ACC System Overview

Components ............................................................................10

Multi-Function Steering Wheel, ACC Displays, Effectsof Acceleration, Braking, and Transmission Controls,Right Distance Regulation Sensor G259, Brake BoosterControl Module J539, Anti-Theft Alarm System Security,Brake Booster

Networked Functions .............................................................30

Data Flow in the CAN Data Bus

Service......................................................................................32

Adjusting the Right Distance Regulation Sensor G259,System Safety, Diagnosis

Glossary ...................................................................................39

Knowledge Assessment .........................................................41

Introduction

1

The Phaeton AdaptiveCruise Control System

The Phaeton Adaptive Cruise Control(ACC) system is an expansion of theconventional cruise control system (CCS).The conventional CCS adjusts the speedof the vehicle to a value preset by thedriver. The ACC system implements thisconvenience function in the same way.

But with its ACC system engaged, thePhaeton’s road speed will also be adaptedto the speed of any other vehicle drivingahead if that vehicle is moving more slowlythan the Phaeton.

In much the same way that bats useultrasonic waves to find their way abouttheir surroundings, the Phaeton ACC systemmonitors the traffic ahead of the vehicleusing radar. Using the data collected, thePhaeton ACC system controls the distanceto the vehicle ahead by decelerating or evenapplying the brakes.

Adaptive Cruise Control is a driverassistance system designed for enhancedconvenience. It actively contributes tosafety by relieving some of the strain onthe driver.

SSP276/034

Introduction

2

ACC Component Locations

Brake Booster

Control Module forDistance Regulation J428with Right DistanceRegulation Sensor G259

Brake BoosterControl ModuleJ539

Introduction

3

SSP276/056

Multi-FunctionSteering Wheel

Control Module with Indicator Unitin Instrument Panel Insert J285(Includes Display Unit in InstrumentCluster Y24 with 5-Inch Color Screen)

4

ACC Operation

Constant Speed

If no vehicle is located within the fieldof vision when the ACC system is inoperation, the desired speed is maintained.

Introduction

62 mph

(100 km/h)

SSP276/006

62 mph

(100 km/h)

➜ 50 mph

(80 km/h)

SSP276/007

Deceleration

If an ACC-controlled vehicle detects aslower-moving vehicle ahead of it in thesame lane, the ACC system regulates thedistance between the two vehicles to atime-dependent value pre-selected by thedriver by reducing the engine speed and, ifnecessary, through a moderate applicationof the brakes.

The driver is prompted to take over thebraking application if the gap between thetwo vehicles is insufficient.

50 mph

(80 km/h)

5

Introduction

The ACC system also reacts to slower-moving vehicles which cut in ahead, bydecelerating. The vehicle road speed isadapted accordingly. 50 mph

(80 km/h)

SSP276/037

50 mph

(80 km/h)

➜ 62 mph

(100 km/h)

Acceleration

If the vehicle in front clears the way byaccelerating or by changing lanes, the ACCsystem increases the engine speed toaccelerate to the pre-selected road speed.

62 mph

(100 km/h)

➜ 50 mph

(80 km/h)

SSP276/009

50 mph

(80 km/h)

➜ 75 mph

(120 km/h)

6

Functional Limits

Speed limitations

The ACC system has an upper speedlimitation of 112 mph (180 km/h).This limit is determined by the 492-foot(150-meter) range of the Right DistanceRegulation Sensor G259 which is housedin the Control Module for DistanceRegulation J428.Higher speeds would require a longerstopping distance than the system cansafely accommodate. A braking operationwould have to be initiated at a greaterdistance to the vehicle in front than canbe measured by the Right DistanceRegulation Sensor G259.The Right Distance Regulation SensorG259 suppresses all stationary objectswithin its field of vision. As a result, thereis also a minimum functional speed of19 mph (30 km/h) below which theACC system cannot be activated.If the ACC system is in the process ofdecelerating from higher speeds, the driveris prompted to take over the braking whenthe minimum functional speed is undershot.

Stationary vehicles are notdetected by the ACC system asthey are approached. The drivermust perform normal brakingoperations when approachingstationary objects.

Lane forecast limitations

When approaching a curve, the ACC systemmay react to a vehicle in an adjacent lane.The ACC system might treat such a vehiclelike a slow moving vehicle in the same lane.The accuracy of the lane forecast comesup against its limits at increasing distancesto vehicles driving ahead, particularly inleft-hand curves.

Introduction

SSP276/036

SSP276/063

7

Introduction

Field of view limitations

Another limitation arises from the narrowangle of vision of Right Distance RegulationSensor G259. It has a horizontal viewingangle of approximately 12 degrees.In tight corners, the viewing angle of thesensor may not be wide enough to detectall vehicles in the same lane. The ACCsystem is designed for curve radii largerthan 1640 feet (500 meters).Road users who cut in just ahead or aredriving at an offset angle, such as themotorcyclist in this illustration, are outsidethe field of vision of the Right DistanceRegulation Sensor G259. The ACC systemis unable to react to these objects.

Deceleration limitations

For occupant comfort, ACC deceleration islimited to about 30 percent of maximumpossible deceleration.However, higher rates of decelerationare necessary if the vehicle approachesa vehicle driving ahead and there is agreat difference in speed between thetwo vehicles.If additional deceleration is required, theACC system prompts the driver to takeover the braking operation.It can generally be said that the ACC systemcan only react as expected if the followingconditions are met:• The Right Distance Regulation Sensor

G259 has correctly detected thedistance, relative speed, and reflectionangle of objects ahead of the vehicle.

• The electronics have assessed thesituation correctly.

It can be presumed that these conditionshave been met when a vehicle symbol isdisplayed in the Display Unit in InstrumentCluster Y24.

SSP276/035

SSP276/063

ACC is designed for operationon highways and country roadsthat are mainly straight.

8

Introduction

ACC System Overview

The ACC system is integrated into thevehicle’s drivetrain electronics.

Data is exchanged with the engineelectronics, ESP, and the transmissioncontrols via the drivetrain CAN data bus.

To ensure an accurate lane forecast, thewheel speed signals generated by theABS wheel speed sensors are sent directlyfrom the ABS Control Module withEDL/ASR/ESP J104 to the Control Modulefor Distance Regulation J428.

Control Module forMulti-FunctionSteering Wheel J453

EngineControl Module

Control Modulewith Indicator Unitin Instrument PanelInsert J285

Con

veni

ence

CA

N D

ata

Bus

Steering ColumnElectronic SystemsControl Module J527

9

Introduction

SSP276/057

Brake Booster

WheelSpeeds

TransmissionControl Module J217

Driv

etra

in C

AN

Dat

a B

usBrake BoosterControl ModuleJ539

Drivetrain CAN Data Bus


ABS Control Modulewith EDL/ASR/ESP J104

10

Components

Multi-Function Steering Wheel

The ACC system is operated by the buttonsin the multi-function steering wheel.

The steering wheel buttons are connectedto the Steering Column Electronic SystemsControl Module J527 which sends the datato the Control Module with Indicator Unit inInstrument Panel Insert J285 via theconvenience CAN data bus.

The gateway in the Control Module withIndicator Unit in Instrument Panel InsertJ285 assumes the data exchange functionbetween the convenience CAN data busand the drivetrain CAN data bus.

To ensure that the driver is informed aboutthe ACC system’s functional state at alltimes, the following information is displayedin the Control Module with Indicator Unit inInstrument Panel Insert J285 and partlysupported by acoustic signals:

• ACC status

• Driver inputs

• Warnings

SSP276/041

Steering ColumnElectronic SystemsControl ModuleJ527

DrivetrainCAN Data Bus

ConvenienceCAN Data Bus Control Module with Indicator Unit

in Instrument Panel Insert J285

11

Components

The ACC system is operated by the leftbutton cluster on the multi-functionsteering wheel. However, the brake andaccelerator pedals, as well as the gearselector lever position, also have aninfluence on the ACC system.

When the engine is started, the ACC isalways in the off state and must be switchedto standby mode by pressing the “ON/OFF”button. The desired speed memory remainsempty and the following distance is set tothe default time-dependent value of1.4 seconds.

SSP276/046

The minimum functional speed of the ACCsystem is 19 mph (30 km/h). While drivingabove the minimum functional speed withthe system in standby mode, the actualspeed can be stored as a desired speedand the ACC can be activated by pressingthe “SET” button.

The desired speed can be reduced in 0.6mph (1 km/h) increments to a minimumvalue of 19 mph (30 km/h) by repeatedlypressing the “SET” button.

Pressing the “CANCEL” button switches theACC back to standby mode while retainingthe desired speed value in memory.

12

Components

The ACC can be reset to the preselecteddesired speed by pressing the “RES” button.

The desired speed can be increased in 0.6mph (1 km/h) increments to a maximumvalue of 112 mph (180 km/h) by repeatedlypressing the “RES” button.

The desired speed can also be increased orreduced in 6 mph (10 km/h) increments bypressing the “ACC+” or “ACC–” button.

The distance perceived by the driver to bea comfortable following distance to avehicle ahead depends on the speed ofthe vehicles. Higher speeds require largerdistances between vehicles.

However, the time that the vehicle withACC system takes to cover the distance tothe vehicle ahead remains constant. Thespeed-dependent following distance is alsoknown as the time gap.

The time gap can be set to a default valueof 1.4 seconds by pressing the “ON/OFF”button. The time gap can be adjusted inseven steps using the thumbwheel tovalues ranging between 1 and 3.6 seconds.

SSP276/047

13

Components

ACC Displays

The driver receives information about theACC system on several displays in theControl Module with Indicator Unit inInstrument Panel Insert J285, some ofwhich are redundant.

• Large ACC display at the center of thecolor screen.

• Small ACC display at the bottom left ofthe color screen.

• LED ring around the speedometer.

• Red symbol for ACC “apply brake” in thetachometer.

• Two-stage acoustic signal.

The LED ring around the speedometerand the red symbol for the ACC in thetachometer are redundant. They providethe minimum necessary information tothe driver in case the color screenis unavailable.

The set desired speed is indicated by theLED ring in the speedometer.

The optical displays are supplemented bytwo acoustic signals: a discrete gong andan aggressive gong.

• The discrete gong sounds when the ACCis switched from the active state to thestandby mode or the off state.

• The aggressive gong sounds along withthe red warning signal.

SSP276/051

14

The large ACC display shares the centerof the screen with various Infotainmentsystems. For this reason it disappearswhen other displays are active.

To maintain information flow to the driverin this case, a small ACC display remainsactive at the bottom left of the screen.

Passive display elements are colored grayand active display elements are orange. Veryimportant information is displayed in red.

Components

SSP276/064

When the ACC system is inactive, thedisplay “ACC OFF” appears.

15

Components

SSP276/065

The activated ACC switches next tostandby mode.

In standby mode, the contents of thedisplay are represented in gray. The largedisplay shows a stylized lane, at the end ofwhich the desired speed is displayed.

When the ACC system is off andthe vehicle is in cruise controlmode (CCS mode), no vehicleahead is detected or displayed.

SSP276/066

After the ACC is turned on by pressingthe “ON/OFF” button, the message“ACC IS STARTING” appears for shortperiod of time.

16

Components

If a relevant object vehicle is detected, itappears in the display.

The color of the mph display changes togray since the displayed speed no longermatches the actual speed.

The time gap (following distance) tothe vehicle in front is represented inseven steps.

The time gap actively set by the driver isrepresented in orange.

The center bar indicates the ACC-equippedvehicle’s position in relation to thevehicle ahead.

SSP276/069

SSP276/067

With the ACC system activated and instandby mode, if a relevant object vehicleahead of the car is detected, it is alsoindicated in gray on the screen.

The small ACC display comes up at thebottom left of the screen and the systemawaits driver input for the desired speed.

The ACC is activated by pressing the“SET” button or the “RES” button.

The active display elements arecolored orange.

SSP276/068

17

Components

If the driver accelerates by pressing theaccelerator pedal, the color of the vehicleshown in the display changes from orangeto gray.

In cruise control mode(CCS mode), the color of thedesired speed changes fromorange to gray.

SSP276/070

SSP276/071

If the driver changes the time gap (followingdistance) by turning the thumbwheel, thedisplay changes for several seconds.

The time gap is indicatedin the small display in theform of several bars inthe graphic and in digitsin the desired speeddisplay field.

SSP276/072SSP276/058

18

Components

SSP276/074

The “ACC SENSOR SOILED” message isdisplayed if the sensor is dirty. However,the system will remain active as long as itcan obtain usable readings.

When the braking performance of the ACCsystem is insufficient, the red warninglights up together with the red symbol forACC “apply brake” in the tachometer,prompting the driver to take control of thevehicle by applying the brake.

SSP276/063

19

Components

If the ACC system internaldiagnostics detect a fault, the message“ACC DEFECTIVE” is displayed andthe system switches to standby mode.After several seconds, the fault messagebecomes passive.

SSP276/075

Effects of Acceleration, Braking,and Transmission Controls

When the ACC system is active, the ACCcan be overridden and the vehicle speedincreased by pressing the accelerator pedal.

If the driver eases pressure on theaccelerator pedal, the ACC resumesoperation and decelerates the vehicle to thedesired speed or to the current time gap(following distance).

Pressing the brake pedal deactivates theACC immediately. The desired speed isretained in the memory and the systemreverts to standby mode.

If the transmission selector lever is movedfrom “D” position to “N,” “R,” or “P”position, the ACC is deactivated. The ACCremains active in all other selector leverpositions.

If the minimum functional speed of 19 mph(30 km/h) is undershot or the upper speedlimitation of 112 mph (180 km/h) isexceeded, the ACC is deactivated.

SSP276/048

SSP276/049

SSP276/050

Components

20

The ACC system is also deactivated byintervention in the brake system by ESP,TCS, EBC, or ABS, but ACC system brakingoperations in progress are completed.Dynamic intervention is independent of anyACC braking operations.

Components

Right Distance RegulationSensor G259

The Control Module for Distance RegulationJ428 houses the Right Distance RegulationSensor G259.

In the ACC system, the distance ismeasured by the Right Distance RegulationSensor G259 based on millimeter-waveradar technology.

SSP276/055

21

The ACC system measures the distance toseveral objects in the field of vision andtheir relative speeds along the longitudinalaxis of the vehicle.

From the measured values, the angulardeviation (azimuth angle, or reflectionangle) from the centerline of the field ofvision is calculated for each object.

Transceiver Unit(Millimeter-Wave Generator)

Evaluation Electronics

Lens

Alignment Mirror

Control Module for Distance Regulation J428with Right Distance Regulation Sensor G259

The radar system uses electromagneticwaves which propagate at the speedof light.

Waves within a frequency range fromapproximately 30 GHz to approximately150 GHz are described as millimeter-waves.

A wave of frequency f requires awavelength of for a wave train.

The transmit frequency of the RightDistance Regulation Sensor G259 is76.5 GHz, the wavelength is 3.92 mm.

= 3.92 mm

The Control Module for Distance RegulationJ428 with Right Distance RegulationSensor G259 is installed behind a plasticcover in the bumper. The lens through whichthe beam is emitted is easily recognizable.

The sensor cover must only bepainted in a millimeter-wavepermeable color. It must not berecoated on the inside or outside,and must not be covered.

The sensor cover must be keptfree of dirt, ice, and snow.

SSP276/010

Components

SSP276/045

Distance

Control Module for Distance Regulation J428with Right Distance Regulation Sensor G259

22

Components

The field of vision of Right DistanceRegulation Sensor G259 can be comparedto the illumination zone of a highly focusedheadlight. As with the headlight, thecenterline of the field of vision of RightDistance Regulation Sensor G259 mustbe exactly aligned in the direction ofvehicle travel.

A microprocessor with high computingpower is integrated in the sender housing.The following additional calculationsare performed:

• Lane forecast.• Selection of the relevant object.• Distance and speed control.• Activation of the engine control module,

brake booster, and Control Modulewith Indicator Unit in Instrument PanelInsert J285.

• Self-diagnosis.


Specifications:

• Transmit frequency: 76.5 GHz• Optical (visual) range: 492 feet

(150 meters)• Horizontal angle of vision (viewing angle):

12 degrees• Vertical angle of vision (viewing angle):

4 degrees• Speed measuring range: ± 112 mph

(180 km/h)

Lens

Sensor Electronics

SSP276/003

Millimeter-WaveGenerator

23

24

Components

Brake Booster Control Module J539

The Brake Booster Control Module J539is located in the plenum chamber on theright-hand side and is only accessible byremoving the coolant expansion tank.

SSP276/059


The Brake Booster Control Module J539controls brake pressure build-up and relief.

For reasons of anti-theft security, thebus interface of the Control Module forDistance Regulation J428 cannot bedeactivated directly. Instead it can onlybe switched off via the Brake BoosterControl Module J539.

SSP276/012

Brake Booster

KL.30AKL.15AKL.31A

Brake BoosterControl Module J539

DrivetrainCANData Bus


25

Components

Anti-Theft Alarm System Security

Because the Control Module for DistanceRegulation J428 with its drivetrain CANdata bus connection is mounted on theexterior of the vehicle, without a safeguardit would be possible to interrogate theimmobilizer code.

To avoid impairing the immobilizer function,a special switch-on procedure is performedby means of the CAN data bus relay in theBrake Booster Control Module J539.


Switch-On Procedure

Starting point (t0):

• Terminal 15 is connected.• Start of Brake Booster Control Module

J539 initialization.

Phase one (t1):

• End of Brake Booster Control ModuleJ539 initialization.

• The CAN data bus relay is closed.• The Control Module for Distance

Regulation J428 transfers a systemmessage via the CAN data bus.

Phase two (t2):

• The Brake Booster Control ModuleJ539 indicates “bus open” to theControl Module for Distance RegulationJ428 to suppress the “bus off” signal ofthe CAN data bus controller.

• The Brake Booster Control Module J539opens its CAN data bus relay.

• The engine electronics interrogate theimmobilizer code on the CAN data busand communicate with the ControlModule for Anti-Theft Immobilizer J362.

Phase three (t3):

• The CAN data bus relay in Brake BoosterControl Module J539 is closed.

• Normal operation of Brake BoosterControl Module J539 commences.

Since the CAN data bus relayin Brake Booster Control ModuleJ539 is open while theimmobilizer is initializing, theimmobilizer code cannot beinterrogated through theControl Module for DistanceRegulation J428.

Terminal 15

SSP276/029t = time


Closed

Open

CAN Data Bus Relay

t0 t1 t2 t3

t

t

t

26

Components

Brake Booster

In the ACC system, the electronic brakebooster has the task of activating thebrakes to control the distance to a vehiclein front. In designing the system, specialemphasis was placed on gradual,comfortable braking.

The Magnetic Coil for Brake Pressure inBrake Booster N247 is a proportionalsolenoid that adjusts in proportion toexciter current. It is integrated in thetandem brake booster together with theBrake Booster Membrane Position SensorG420 (a stepless potentiometer) and theAutomatic Distance Regulation ReleaseSwitch in Brake Booster F317.

To achieve high braking quality, the brakepressure is controlled by measuring thebrake pressure at the brake master cylinderwith the Brake Booster Pressure SensorG294. At the start of the control process,the pressure controller is subjected to amembrane position control.

During an electrically activatedbraking operation, the brake pedalmoves accordingly.

SSP276/042

Brake BoosterPressure SensorG294

Connector

Brake Booster MembranePosition Sensor G420

VacuumChamber

WorkingChamber

MagnetArmature

Atmosphere

Disc Seal

Valve Body

Magnetic Coil for Brake Pressurein Brake Booster N247

Membrane Disc

VacuumConnection

MembraneSpring

MasterCylinder

Automatic DistanceRegulation ReleaseSwitch in BrakeBooster F317

27

Components

Automatic Distance Regulation

Release Switch in Brake Booster F317

The Automatic Distance RegulationRelease Switch in Brake Booster F317helps to distinguish whether the brake waselectrically activated.

Since the Automatic Distance RegulationRelease Switch in Brake Booster F317 is asafety-critical component, it is designed asa two-way switch with both a normally-closed (NC) contact and a normally-open(NO) contact. This enables the system torecognize whether the switch is in either itsrest or working position.

In the rest position or when the brakebooster is electrically actuated, no force isapplied to the elastic reaction disc by theactuating rod:

• The reaction disc is relieved of pressure.• The Automatic Distance Regulation

Release Switch in Brake Booster F317rests against the housing of thebrake booster.

• Electric circuit 1 is closed.

SSP276/044

Reaction Disc Actuating Rod

Automatic DistanceRegulation Release Switchin Brake Booster F317

1

2

If the brake is applied, pressure is appliedto the reaction disc by the actuating rod:

• The reaction disc is compressed.

• The Automatic Distance RegulationRelease Switch in Brake Booster F317rises from the brake booster housing.

• Electric circuit 2 is closed.

SSP276/062

Reaction Disc

Automatic DistanceRegulation Release Switchin Brake Booster F317

Actuating Rod

1

2

28

Components

Initial Position

When the brake booster is in its startingposition, the vacuum has built up and theproportional magnet is de-energized.

The functional mode of the electronic brakebooster is determined by the orientation ofthe valve body and magnet armaturesealing edges against the disc seal.These sealing edges act as valves.

The pressure in the working chamberis determined by the positions ofthese valves:

• The sealing edge of the solenoid magnetarmature acts as an inlet valve.

• The sealing edge of the valve body actsas an exhaust valve.

• Both valves open and close when thesealing edge lifts off or rests against thedisc seal.

Pressure Build-Up

When pressure build-up is electricallyactivated, the Magnetic Coil forBrake Pressure in Brake Booster N247is energized.

The air gap between the stator and thesolenoid magnet armature becomes smaller.

The inlet valve at the sealing edge of themagnet armature opens, and atmosphericair flows into the working chamber.

The membrane disc compresses themembrane spring.

Up to approximately 30 percent of thebrake pressure can be achieved.

SSP276/043

Magnet ArmatureSealing Edge

DiscSeal

Valve BodySealing Edge

ValveBody

Magnetic Coil forBrake Pressure inBrake Booster N247


Magnet Armature

Disc Seal

Stator

Inlet Valve at MagnetArmature Sealing Edge

WorkingChamber

MembraneDisc

SSP276/031

29

Maintaining the Pressure

To maintain pressure, the current flowingthrough the Magnetic Coil for BrakePressure in Brake Booster N247 is reduced.

The armature spring pushes the stator andthe magnet armature apart, closing the inletvalve at the magnet armature sealing edge.

The partial vacuum in the working chamberdefines the position of the membrane disc.

Components

SSP276/032


Disc Seal

Armature Spring


SSP276/033

WorkingChamber

Exhaust Valveat Valve BodySealing Edge

VacuumChamber

Valve BodyPressure Relief

If the Magnetic Coil for Brake Pressure inBrake Booster N247 is de-energized, themagnet armature pushes the disc seal backover the inlet valve sealing edge.

As the disc seal moves away from it, theexhaust valve at the sealing edge of thevalve body is opened.

The air in the working chamber flows intothe vacuum chamber and is drawn offthrough the engine.

The membrane spring relaxes.Disc Seal

MembraneDisc

WorkingChamber

30

Networked Functions

Data Flow in the CAN Data Bus

The Control Module for Distance RegulationJ428 is interfaced to the drivetrainCAN data bus via the data bus relay in theBrake Booster Control Module J539.

The Control Module for DistanceRegulation J428 communicates withthese control modules:

• Brake Booster Control Module J539

• Engine Control Module

• Control Module with Indicator Unit inInstrument Panel Insert J285

• Steering Column Electronic SystemsControl Module J527

• Transmission Control Module J217

• ABS Control Module withEDL/ASR/ESP J104

The following table blocks out theautomatic distance regulation systemdata flow between the various controlmodules through the drivetrainCAN data bus network.

Brake pressure request.Request brake preset.Interrogate bus relay.

Control Module

for Distance

Regulation J428

Brake Booster

Control Module

J539

Driver applies brake.Release switch plausible/implausible.CAN data bus relay open/closed.Status of electronic brake booster.

Torque request.ACC status.

Engine torque.Accelerator pedal angle.Driver takes control of accelerator pedal.Emergency running/ready.

Control Module

for Distance

Regulation J428

Engine

Control Module

31

Networked Functions

ACC status.Desired speed.Set time gap.Object detected.Current distance.System limits reached.Activation of gongs 1 and 2.Sensor blind.

Control Module

with Indicator

Unit in

Instrument Panel

Insert J285ACC display error.Speed displayed on speedometer.Display time gap.

Control Module

for Distance

Regulation J428

Multi-function steering wheelcontrol inputs.Steering angle.

Steering Column

Electronic

Systems Control

Module J527

Transmission

Control Module

J217

Current gear.Selector lever position.Emergency running.

ABS Control

Module with

EDL/ASR/ESP

J104

Control Module

for Distance

Regulation J428

Control Module

for Distance

Regulation J428

ABS, TCS, ESP intervention.Yaw velocity.Brake pressure.

Control Module

for Distance

Regulation J428

32

Service

Adjusting the Right DistanceRegulation Sensor G259

The Right Distance Regulation Sensor G259is adjusted by means of two adjustingscrews (S1 and S2) located on the right sideof the Control Module for DistanceRegulation J428.

A single screw clamps the left side of theControl Module for Distance RegulationJ428 to a ball joint, which serves as a thirdbearing point.

The adjusting screws have six detentpositions per rotation.

Turning adjusting screws S1 and S2evenly swivels the Control Module forDistance Regulation J428 with RightDistance Regulation Sensor G259 on thehorizontal plane.

Turning adjusting screw S2 by itself swivelsthe Control Module for Distance RegulationJ428 with Right Distance RegulationSensor G259 on the vertical plane.

SSP276/053

Right Side

S2

S1

AlignmentMirror

ClampingScrew

Left Side

Welded-OnSteel Bracket

Control Module for DistanceRegulation J428 withRight Distance RegulationSensor G259

33

Service

Align the centerline of the Right DistanceRegulation Sensor G259 detection field onboth the horizontal and vertical planes.

• On the horizontal plane, align thecenterline (radar axis) parallel with thedriving axis.

• On the vertical plane, set an declinationof 1 degree of angle downward from thehorizontal plane.

Mechanical adjustment ofthe Control Module for DistanceRegulation J428 with RightDistance Regulation Sensor G259is absolutely necessary after:

• Adjustments to thesuspension.

• Replacement ofControl Module forDistance Regulation J428or crossmembers.

• Crossmember issubjected to mechanicalstress (collision).

SSP276/052

1°

Radar Axis

Horizontal

Road

Vertical Adjustment Direction

Vertical Plane

SSP276/038

Horizontal Adjustment Direction

Radar Axis

Driving Axis

Horizontal PlaneHorizontal Detection Field

34

Service

Adjustment MethodThe driving axis is determined using awheel alignment test stand and the ACCadjustment device VAS 6041.

A laser pointer is attached to the VAS 6041level with the Right Distance RegulationSensor G259.

A target disc is positioned between thelaser pointer and the Right DistanceRegulation Sensor G259. The target dischas a center hole through which the beam

of the laser pointer can be shined on thealignment mirror of the Right DistanceRegulation Sensor G259.

When the suspension is adjusted, themeasuring equipment of the test bench isaligned in parallel with the driving axis.

The ACC adjustment device VAS 6041is aligned with the driving axis using thefront axle transducers together with therear axle transducers.

Setup for Adjustment

SSP276/013

Front Axle Transducer

ACC Adjustment Device VAS 6041

Target Disc

Laser Pointer

Front Axle Transducer

35

Service

If the Right Distance Regulation SensorG259 is perfectly aligned, the laser beamshould be reflected through the center holein the target disc.

If the Right Distance Regulation SensorG259 is not properly adjusted, the laserbeam will hit the target disc in one of thefour quadrants. The Right DistanceRegulation Sensor G259 must be alignedusing the adjusting screws on the ControlModule for Distance Regulation J428 sothat the reflected laser beam passesthrough the center hole in the target disc.

In the horizontal plane, a high degree ofadjustment accuracy is required. Onlya rough adjustment can be made usingthe adjusting screws. Fine adjustment iscarried out electronically inside theControl Module for Distance RegulationJ428 with Right Distance RegulationSensor G259 while driving.

SSP276/014

Adjustment:

�: Rotation using S2�: Rotation using S1 and S2

Longitudinal Axisof Vehicle =Radar Normal

Mirror Normal

Alignment Mirror

X

1

2

3

4

ZY

�

�


36

Service

Correcting an Indication Error

The mirror normal and the centerline of thedetection field (radar normal) do not matchup for production reasons.

The indication error in the horizontal andvertical planes is measured at the factoryand stored in the memory of ControlModule for Distance regulation J428 withRight Distance Regulation Sensor G259 asa correction value.

The indication error is specified as anumber of detents of the adjusting screw.

The correction values can be exported withthe VAS 5051.

Once adjusted to the correction values, thelaser beam moves from the center into oneof the quadrants. To check that theadjusting screws have been turned in the

SSP276/015

correct direction, the target quadrant is alsostored in the sender memory.

Data block 06

• Measured value 2: AZOF mirrorindication error in the horizontal plane(AZOF = AZimuth OFfset).

• Measured value 3: ELOF mirrorindication error in the vertical plane(ELOF = ELevation OFfset).

You will find details foradjusting the alignment of theRight Distance Regulation SensorG259 in the Repair Manual.

Longitudinal Axisof Vehicle =Radar Normal

Mirror Normal

X

1

2

3

4

Z Y

�

�

Adjustment:

�: Rotation using S2�: Rotation using S1 and S2

37

Service

System Safety

A series of measures have been taken toprevent a faulty ACC system from posing adanger to other road users or resulting ina breakdown.

The most important measures are brieflyexplained below.

Automatic Distance Regulation Release

Switch in Brake Booster F317

The Automatic Distance RegulationRelease Switch in Brake Booster F317must reliably recognize driver brakeactuation in order to switch the ACCsystem to standby mode. For this purpose,the switch is designed as a two-poletwo-way switch.

Spiral Spring in the Steering Wheel

Steering wheel button information istransferred via a serial bus routed throughthe spiral spring of the steering wheel.

To ensure that the ACC system is turnedoff by the “ON/OFF” button in the event ofa CAN data bus failure, this information isredundantly transferred via a separate wirethat originates at the spiral spring.

Redundant ACC Displays

If the color screen in the Control Modulewith Indicator Unit in Instrument PanelInsert J285 fails, the red symbol for ACC“apply brake” in the tachometer and theLED ring around the speedometer providethe driver with the minimum necessaryinformation about the ACC system.

Coupling the ACC System to

the ESP Function

The ACC system is turned off or cannotbe activated when the ESP function isnot available.

If ESP is activated during an ACC brakingoperation or if it fails, the ACC brakingoperation is nevertheless completed.

CAN Data Bus Disconnect

Since the Control Module for DistanceRegulation J428 with Right DistanceRegulation Sensor G259 must be mountedin an exposed position at the front end ofthe vehicle, there is a danger that it mayreceive damage.

To prevent the vehicle from breakingdown if the drivetrain CAN data bus failsas a result of a CAN data bus blockade bythe Control Module for Distance RegulationJ428, this module is disconnected by theCAN data bus relay in the Brake BoosterControl Module J539.

38

Service

Diagnosis

The Control Module for Distance RegulationJ428 and the Brake Booster ControlModule J539 continuously test for properfunctioning. Any faults they detect aresaved to the fault memory.

The faults stored can be accessed and“Guided fault-finding” can be performedusing the Vehicle Diagnosis, Test andInformation System VAS 5051.

You will find detailed informationon ACC system diagnosis in theRepair Manual.SSP276/039

SSP276/057a

Control Modulefor Multi-FunctionSteering Wheel J453

WheelSpeeds

TransmissionControl ModuleJ217

BrakeBoosterControlModuleJ539


Control Module forDistance RegulationJ428 with RightDistance RegulationSensor G259

Brake Booster

ABS Control Modulewith EDL/ASR/ESP J104

Engine ControlModule

Control Modulewith Indicator Unitin Instrument PanelInsert J285

ConvenienceCAN Data Bus

Steering ColumnElectronic SystemsControl Module J527

Driv

etra

inC

AN

Dat

a B

us

39

Glossary

Azimuth Angle

See “Reflection Angle.”

Desired Speed

The speed selected by the driver in CCSmode. In ACC mode, the actual speed isless than the desired speed.

Detection Field

See “Field of Vision of Sensor.”

Driver Assistance System

Driver assistance systems are systems thatsupport the driver without relieving him ofhis responsibility to guide the vehicle safely.

Driving Axis

Direction of movement of the vehicle withthe steering wheel in the straight aheadposition.

Electronic Brake Booster

The electronic brake booster is a pneumaticbrake booster which can operate the brakeby means of an electromagnetic valve. Thededicated Brake Booster Control ModuleJ539 ensures precise brake pressureapplication.

Elevation Angle

Vertical reflection angle.

Field of Vision of Sensor

The region in front of the ACC-equippedvehicle in which vehicles and obstacles aredetected. Comparable with the illuminationzone of a headlight (also referred to asdetection field).

Following Time

The road speed-dependent distance to avehicle in front (also referred to as timegap).

Gateway

Electronic circuit or circuit componentwhich facilitates data exchange betweenvarious CAN data buses.

Indication Error

Angular error in relation to the idealdirection.

Lane ForecastThe ACC system should only respond tovehicles driving ahead of the vehicle in thesame lane. This requires a lane forecast.The system calculates the lane ahead fromthe measured variables of wheel speeds,yaw rate, and steering wheel angle.

Millimeter-Waves

Electromagnetic waves in the frequencyrange from approximately 30 GHz to 150GHz. The limits are fuzzy and are referredto as millimeter-waves since theirwavelength is in the millimeter range.

Mirror Normal

Line perpendicular to the surface ofthe mirror.

Proportional Solenoid

Solenoid whose armature length isproportional to the coil current in thedesign range.

40

Glossary

Proximity Controller

The Right Distance Regulation SensorG259 is the proximity controller in thePhaeton ACC system. It calculates thenecessary engine torque or braking torquefrom the measured variables of distanceand relative speed to maintain the adjustedfollowing time to a vehicle driving in front.

Radar Axis

Axis of symmetry of the radardetection field.

Redundant

Components or signals that duplicate thefunctions of others for increasing fail safety.

Reflection Angle

Horizontal angular deviation of an object inrelation to the radar center line (alsoreferred to as azimuth angle).

Release Switch

The Automatic Distance RegulationRelease Switch in Brake Booster F317 is atwo-way switch integrated in the electronicbrake booster to detect brake application bythe driver and brake application initiated bythe ACC.

Relevant Object

An object that the Right DistanceRegulation Sensor G259 in the ACCsystem uses for proximity control basedon distance and relative speed.

Stator

Stators and armatures form the magneticcircuit of a solenoid. The stator is thestationary part and the armature is themoving part.

Steering Column Electronic Systems

Control Module J527

The Steering Column Electronic SystemsControl Module J527 sends steering wheelbutton information to the convenienceCAN data bus. The information provided bythe steering angle sensor is sent to thedrivetrain CAN data bus.

Time Gap

See “Following Time.”

Knowledge Assessment

41

An on-line Knowledge Assessment (exam) is available for this Self-Study Program.

The Knowledge Assessment may or may not be required for Certification.

You can find this Knowledge Assessment at:

www.vwwebsource.com

From the vwwebsource.com Homepage, do the following:

– Click on the Certification tab

– Type the course number in the Search box

– Click “Go!” and wait until the screen refreshes

– Click “Start” to begin the Assessment

For Assistance, please call:

Certification Program Headquarters

1 – 877 – CU4 – CERT(1 – 877 – 284 – 2378)

(8:00 a.m. to 8:00 p.m. EST)

Or, E-Mail:

[email protected]

Volkswagen of America, Inc.3800 Hamlin RoadAuburn Hills, MI 48326Printed in U.S.A.August 2003

The Phaeton Adaptive Cruise Control Design and Function

Documents

Transcript of The Phaeton Adaptive Cruise Control Design and Function