hydractive citroen official training manual

8/10/2019 Hydractive Citroen Official Training Manual

1/78

TECHNICAL TRAINING


2/78

HYDR CTIVE SUSPENSION

INTRODUCTION

The choice of spring and damping settings of a vehicle's suspensionis

based on two maintriteria.

I - COMFORT

The flexibility and the damping rate are defined so as to isolate theoccupants of the vehicle from

impads

and vibrations by using anoscillating frequency btween0.9 and1.2 Hertzand by limiting verticalaccelerations to 0.25 g (2.45 mls2).


3/78

I

PRINCIPLEOFHYDRACTIVESUSPENSION

For a vehicle t o be comfortable, i t s suspension must be set t o be supple

in flexibility, damping and anti-roll.

These settings do not allow themovement of the vehicle to be

controlled properly when disturbed. In this case, firm suspension isneeded which reduces comfort.

Standard suspension is a compromise defined as a function of the typeof vehicle (family or sports). The role of hydractive is to offer these two

types of settings and to select the ideal solution automatically asa

function of the driving conditions:

No disturbance :supple suspension promoting comfort,

Disturbance: firm suspensionto control themovementso f the vehicle


4/78

Switching t o firm by anticipation

The computerwin switchto the firm position asa function of theevents which risk compromising the stability of the vehicle. The

suspensionwill therefore becomeharder before the vehiclehas

moved.

Switching t o firm by reaction:

EVENT ,

Bend

Steering wheelturned

Request for power

Engine brake

Braking

Th i h h fi i i f i f h

VALUE MEASURED

Angle of rotation

Rotational speed

Development speed

of the acceleratorpedal

Front brake pressure

SENSOR

Steering wheel

Steering wheel

Accelerator pedal

Brake


5/78

* Example of the new laws for switching from the supple state to the

"firm"state.

On the motorway at 120 kmlh(75 mph), in the "auto" position,

switching to "firm" occurs for a steering wheel angle greater than

33 degrees, thisstate i s maintained for 1.2 seconds when the

steering wheel returns to an angle less than 33 degrees. In the

same configuration, in the "sport"position, switching to "firm"

occurs for an angle of 22degrees and this state is then maintained

forl 6 seconds.

On country roads or in town, at 50 kmlh(31 mph), switching to"firm"occurs for a steering wheel angle of 120degrees (a third of

a turn of the steering wheel) when in the"auto

"position and the

time delay is1.2 seconds. In the same conditions, in the "sport"position, switching from supple to "firm" occurs for an angle of 80degrees and this time the time delay is 1.6 seconds.

I VARYING THESPRING


6/78

B - THE HYDROPNEUM TICSPRING

Nitrogen

Membrane

Fluid

The elastic element consists of a

mass of nitrogen of which t he

pressure and volume vary as a

function of the force F applied to

the piston

i

.

Piston


7/78

Comments:

When thevehicle is loaded the volume of nitrogen inthe spheres


8/78

I1

VARIABLE DAMPING

This consists of putting two shock absorbers in parallel and isolating, ornot, one of them to vary the damping.

A - SOFT POSITION

The fluid passes through A towards the main sphere and throughA towards

the additional sphere. Fluid braking is low since the

fluid can flow in two ways +damping is low.


9/78

ANTI-ROLL

-REMINDER OF HOW STANDARD HYDROPNEUMATIC SUSPENSIONWORKS

\

Direction of roll


10/78

B - ACTIVE ANTI-ROLL OFHYDRACTIVESUSPENSION

The circuit i s modified with respect to the standard system in theboth states.

1 - "Soft" state

Vd

Shock absorber


11/78

10

PRESENTATIONOF THE ASSEMBLY

SUMM RY DIAGRAM

Inputs

Outputs

ront stiffness regulato r

SPORT control control electrovalve

Steering wheel

sensor

Vehicle distance

M

ensor

P

piegulator

Light on SPORT

switch


12/78

- POSITION

L M NT

POSITION

Steering wheel sensor

On the steering column behind the steering

wheel

Computer

Control switch

Vehicle speed sensor IOn the gearbox tachometricsocket)

Ventilated housing on the front right wheel

arch under the bonnet

Central console behind the height control

lever

-

Front stiffness regulator electrovalve

Behind the cooling radiator at the front l e f t

Accelerator pedal travel sensor

Braking pressure sensor

Bodv movement sensor

On the pedal arm

-

On the front left of the engine sub-frame

-

Riqht of the front sub-frame


13/78

DIAGRAM OF OPERATING PRINCIPLE

COMPUTER

BOOT

SWITCH

DOOR

SWITCHES

BODY

MOVEMENT

SENSOR

CCELERATOR

PEDAL

SENSOR

SUSPENSION

SWITCH

I

T

VEHICLE

SPEED

SENSOR

STEERING

WHEEL

SENSOR

\

I

v

v

~r

~r

I

7

f


14/78

13

OPERATION OF THE HYDRAULICPART

PRESENTATION

Parts list

1 Front electrovalve

Front stiffnessregulator

Rear electrovalve

Rear stiffnessregulator

Front heightcorrector


15/78

The system differsfrom standard suspension due to the addition of tw

stiffness regulators and (one per axle) each incorporating an

electrovalve.

Note that the pipes connecting the suspension elements to the

regulators havea large diameter (8X

10) in order to reduce load losses

and therefore the response time. Sealing is provided by I S 0 taperedconnectors without gaskets. The tightening torque is 3 to 3.5 mdaN

THE ELECTROVALVE

A-

ROLE

This allows the stiffness regulator to be controlled hydraulically

according to the electrical information it receives from the


16/78

C - OPERATION

I At restAs the coil (5) is notenergised, the spring 1)presses the needle (2) ontothe seat (6).

The following are connected

B

A . L

The user circuit output B i stherefore connected t o thereservoir C.


17/78

D - CHARACTERISTICS

Nominal voltage 13 5V

Nominal intensity 3 A when powering up for 0.5 seconds with

the maximumvoltage.

0.5A when holding by disconnectingthesupply voltage

Maximum cut-outtime < 1.8ms

Resistance 4.8

Control frequency l000z

Hydraulic


18/78

THE STIFFNESS REGULATOR

A ROLE

Two stiffness regulators are fitted (one front and one rear) which

modify the physical state of the suspension as a function of the

status of the electrovalve.

B - CONSTITUTION

Parts list

1 Additional Sphere

3 - Slide valve


19/78

18

C - OPERATING PRINCIPLE

l "Soft" state

HighPressure

Reservoir


20/78

When the electrovalve is energised, the slide valve (3) is subjectedto the high pressureHPon one side and to the suspension pressure

PSon the other.

SinceHP>PS

the slide valve is locked in the "Soft" position.

There is thereforea link between the two suspension elements

and the additional sphere.

This gives:

Large volume of gas (suspension spheres additional sphere)

- soft suspension.

Fluid passes through four shock absorbers (to reach thedditi l h th fl id th h th h k


21/78

2 "Firm" state

HighPressure


22/78

Sthe electrovalve is not energised, the slide valve (3) is subjected to thesuspension pressure PSon one side and to the reservoir pressure

Pr

on theother. Since PS Pr, the slide valve is locked in the "Firm" position.

The additional sphere is therefore completely isolated and the main link

between the two suspension elements i s broken.

Therefore, there is :

Small volume of gas (additional sphere isolated)

Firm suspension

Fluid no longer passes through the shock absorbers(5) since theadditional sphere i s isolated.


23/78

111- STIFFNESS REGULATOR BALL VALVE

A - ROLE

This allows:

In the "Firm" state, the suspension elements to be connectedt

the height corrector during correction or,

e The suspension elements to be isolated for roll, thereforepreventing fluid flowing between the two spheres.

B CONSTITUTION

Parts l i s t

1 - End Stop


24/78

3 - OPERATION

1-

Anti roll When rolling, fluid tends to flowfrom one suspension element tothe other. Itmoves the ball (5)which presses against the seat 4),thus closingthe connection.

As the pressure of the compressedsuspension element is greaterthan that of the extendedsuspension element, the ball i slocked whilst the vehicle is rolling.When the roll stops, there is nolonger any transversestrain onthe vehicleand the ball isreleased.

4 5 6 When turning in the oppositedirection, the ball i s pressedagainst the seat (6)


25/78

3 Outlet correction

Under the effect of the fluiddischarged by the suspension

elements, the ball presses againstthe thrust rod 2) .This thenpresses against the end stop l ) , ti s therefore locked in this positionand does not prevent the fluidflowing.

At the end of the correction, theflow is zero and the ball isreleased.

25


26/78

25

ELECTRONIC OPERATION

I PRINCIPLE

The suspension has two stiffness states and two damping states.Changes in state are controlled by anticipationbyone of the four

parameters of steering wheel angle steeringwheel speed, braking andthe amount the pedal is pressed down

a weH

asby analysing thevertical movement of the body (amplitude of the movement).

The parametersfrom the sensors are compared with variable

thresholds as a function of the vehicle speed. The state changes t o firmwhen the threshold is exceeded; returning to the supple (or soft) stateoccurs when the value of

the parameter is once again lower that thethreshold and after a time delay has elapsed.

COMPUTER


27/78

B - CONSTITUTION

This i s a sealed unit into which are fitted the various electroniccomponents.

The link to the outside i s provided by two connectors each withfifteen channels (one white and one black), which can bedisconnected in any order.

The heart af the computer consists of two TEXAS INSTRUMENTS16kB and

4kB

microprocessors.

The control transistors of the electrovalves (called "intelligent")

are capable of detecting open circuit and closed circuits.

Integrated circuits monitor the supply voltage and protect thecomputer.

C CHARACTERISTICS


28/78

111- SENSORS

A

-

SPORT

CONTROL SWITCH

1

Role

This allows the driver

to

impose the

SPORT

rule.

2

-

Constitution

-

Operation

.

+

ights

I

B 4

C

P


29/78

B - EATON SPEED SENSOR

a) Role

This sensor supplies an electrical signal which is proportionalt o the rotational speed of the secondary gearbox shaft, andtherefore t o the vehicle speed.

b) Position

It is mounted onto the tachometricsocket of the gearbox

c) Operation

1 - Polar wheel

2 H ll


30/78

The essential element of this system i s a plate of 1.2mm length.

current passes over this plate between points and

B.

If

there

i s

no magnetic field, no voltage is obtained between-the equidistant

points E and F.

When a

S N

magnetic field i s applied a t right angles to the plate, a

very low Hall voltage of 0.001 volts

i s

obtained between points

E

and F.

This comes from the deflection of the A B current l ines by the

magnetic field, provided that

the

two simultaneous conditions of

electric current and magnetic field are satisfied).

Operation

Speedo cable

circuit


31/78

d) Calculating the speed

The sensor supplies square signals, of which the frequency isproportional to the speed

We know that the sensor supplies:

- Eight pulses per revolutionof the polarwheel


32/78

C - STEERING WHEEL SENSOR

1 Role

This generates signals which enable the computer to definethe angle and the speed of the steering wheel.

2 Constitution

It is a double optoelectronic sensor. It consists of two l ightemitters, two receivers and a phonic wheel with windows. Thesensor is fixed and the phonic wheel tur s with the steeringwheel. The phonic wheel and the sensor form a compactaleo

make unit, indexed in rotation.

Parts l is t


33/78

3 Operation

Reminder of a photodiode

A photodiode is made from a PNjunction which can beilluminated externall . Its reverse conductivity isproportional to the il umination.

Light

Junction

Inverse voltage:l0V

0 10 20 30

Radiation


34/78

W e therefore have:

A ~ O O O O O O O

A - Emitter

-c

B

L

Receiver

C

Phonic whee l

D Displacement

S Output

4


35/78

d) Operating principle

The computer supplies the sensor with + 5 volts.

C + 5Vsupply

NI0

M

P

U

T

NI

5

9,5

A3

-

S11

N9

9 5

V

A1

.

S21

@

B 3 B

R

..

.

l

C 2

Jo

STEERING WHEEL

SENSOR


36/78

5 Processing of the signal by the computer

a) Work done by the computer

Interprets the signals from the sensor (number ofsteps)

Determines the direction of rotation

Determines the straight line positionCalculates the angle of the steering wheel with~espectto the calculated straight line

Calculates the rotational speed of the steering wheel

Compares the values of the rotational speed and theangle found with the switching to firm thresholds ofthe computer.

Controls, or not, switching of the suspension to the"fi "


37/78

c) Deterining the direction of rotation

As the computer knows the logical order of the codes, itjusthas to compare the new code with the old code to work outthe direction of rotation.

0

New1

0

New 1

0

Old - Left1

Old 1 Right

d) Determining the straight lineDefinition of the "calm steerinq wheel" notion

The steering wheel i s said to be "Calm" when i t s movementsremain within a sector of + 6.5" with respect to a zero point


38/78

The new position of the steering wheel becomes the newpoint

PO, a newse tor

of13

centred aboutPO i s created and

therefore the steering wheel becomes calm, the distancetravelled counter returns to zero and the computer calculatesthe average of the steering wheel positions in this sector.

Definition of distances

The following are known as:

D distance over which the computer has calculated thestraight line,

[BP distance travelled with the steering wheel calm

Application:

Steeringwh i calm 1 Steeringwheelnot calm Steeringwheel calm 2


39/78

Updatinq the straiqht I ine

The computer memorises the straight line osition LD (average of thepositions in the sector: Sum of the num er of steerinq wheel positions

number of acquisitionsand th e distance D over which it has been calculated.

The first straight Iine memor.ised LDo is the position of th e steering whee lwhen Vveh = 30 kmlh PO), therefore the distance memorised i s D

=

0.

A new straight line LDwill

be memorised (average o f the positions in t hesector) as wel l as the distance D over which it was calculated if one of theset w o events arises:

Distance travelled with steering wheel calm DP more than 50 metresthant ha t memorised D: DP = D + 50. Therefore, for as long as thesteering wheel is calm, updating w il l occur every 50 metres, t hememorised distance D increasing by 50 m.

Example :distance memorised D = 500 metres. Af te r travelling adistance DP = 550 metres with steerin wheel calm steering whee lposition updated and Dbecomes equa t o 550 metres Then a t DP


40/78

e) Measuring the angle

The computer counts the code changes emitted by the sensor

with respect to the straight line it has defined.

f

Measuring the speed of rotation

The computer counts the code changes emitted by the sensorin one second.

NOTE:

The

ECU accepts rotational speed signals of up to 2.5" per milli secondfrom the steeringwheel sensor. Any value above this threshold has the same effect.


41/78

SYNOPTIC FOR DETERMINING

STRAIGHT AHEAD POSITION

VS 18

MPH

+6.5

around PSW

DT

0


42/78

D - ACCELERATOR PEDAL TRAVEL SENSOR

1 - Role

This enables the computer to know theposition of theaccelerator pedal.

2 Constitution - Operation

It consists of a variable resistor, of which the cursor i scontrolled.bythe pedal.

Parts

i s t

1 -Protective resistor

2 - Receiving track

3 -Cursor

4 - Resistor


43/78

Characteristics

Main resistor

Protective resistor

4

Computer processing of the signal

a) Work performed by the computer

Reads the sensor voltage with the accelerator pedal

in he 'throttle closed' position and the sensor

voltage with the pedal in the 'throttle open' position.

Deduce the actual electrical stroke of the sensor from

this information.

Divide this actual stroke into a certain number o

steps.

Check how many steps are covered in 32 ms (speed a t


44/78

Previously, the throttle closed position should have beenbetween 10 and 30% of the total theoretical electricalstroke; this was too restrictive and from now on thecomputer will use a minimum effectiveelectricalstroke of100steps for analysing the development of theaccelerator pedal.

The computer has the total electrical stroke stored in i t smemory 0 to 5V,divided into 255 ste which gives avalue of 0.0196 V per step. It is consi4ered that, with thesensor fitted, the throttle closed' should be a maximumof 125 steps, thus giving a minimum effective stroke of

100 steps.

In reality, the computer knows how to adapt t o al lsituations.


45/78

Example:

255 steps divided by 5 V gives a value of 0.0196 V fo r one step.

In theory:

- th ro tt le closed = 125 steps+ 2.45 V- thro tt le open = 255 steps A step = 100 steps = 1.09V

2.45 + 1.96 =4.41- 35 st ps + 0.6V - 0 t o 0.6V =Short circuit fau lt zone- 233 steps 4 5V - 4.5 t o 5 V = Open circuit fau lt zone

The driver swtiches th e ign it ion on:

- The computer reads 1.96 V; 1.96 < 2.54 V (throt tle closed a t 125 steps)

The computer takes these values of 1.96V thus 1.96 + 1.96= 3.92 V. It

therefore has aminimum effective stroke o f 100 steps between 1.96V(throt tle closed) and 3 92 V (throt tle open).

- The driver presses the accelerator pedal and t he computer receives avoltage of 4 47 V; 4 41 V (thrott le open a t 255 steps);


46/78

E - BRAKING PRESSURE SENSOR

This i s a pressure switch i s closed a rest

Nll

B 2 B11

It i s closed for a braking pressure S 35 bar and open for a brakingpressure > 35 bar.

The computer reads the electrical signala t i t s terminal N 11:

If P 35 bar > earth signal,

If P > 35 bar > ''OpenN-- 5 V

F BODY MOVEMENT SENSOR

Role


47/78

3 Operation


48/78

5 Processing of the signal by the computer

a) Work performed by the computerInterprets the signals from the sensor (number of steps)

Determines the direction of rotation of the ring (leadingor trailing)

Calculates the displacement speed

Determines.. the. average height (Have) and updates it. . ... :

Calculates the movement by the difference with theaverage height

comparesthe movement values found with the switchingto firm thresholds of the suspension

, Controls, or not, switching of the suspension to the"firm" state


49/78

G - THE DOORSAND T ILG TE

The aim of the door or tailgate switches is to provide an earthsignal to the computer or not.

They are used for the anti-jolt function which will be discussedlater. The earth s i nal is present when one of the doors or thetai lgate

is opene

Contacts open, a voltage of 12 V is measured at terminals B6and87

.

.

B


50/78

IV STRATEGIES FOR SWITCHING TO FIRM

A PRINCIPLE ELECTROVALVE CONTROL

Normally, the suspension is "supple" (three spheres per axle); thecomputer switches to "firm" (two spheres per axle) via one of thefollowing parameters :

Steering wheel angle( steering wheel sensor

Steering wheel speed )

Amplitude of vertical movement in bothdirections bodymovementsensor

.. .,,

..

Braking brake sensor

Speed the accelerator pedal is being pressed or lifted- pedalsensor


51/78

B -

SWITCHING TO FIRM IN ANTICIPATION

1-

Steeringwheel

a) Using th e angle of rotation

The vehic le speed must have exceeded

30

km h on ce and

the angle must be reater then a l im i t w h ich

IS

a function

f t he vehicle spee .

The suspension wil l return t o soft w he n t h e st ee rin g

wheel angle becomes less than a li m it value

and

a f te r a

1.2 s t imer.

Note:

In the s o r t position, each lim it fo r sw itching t o firm

i s

divide

B

y

1.5

and the timer for retur ning

to

soft

is

mult ipl ied by 1.3.

STEERING WHEEL ANGLE LIMITS

Norm al position)


52/78


53/78

FIRM

STEERINGWHEEL

ANGLE

LIMITS

Normal position)

1605

600

5

l

-

1

1

I s 5

.

400

Steering

wheel

angle

degreesh) 300

-

200

-

--


54/78

Specific case of steering wheel centring

Through experience, it has been realised that the steering wheelalways returns to the straight line osition quicker than when it

fmoves to the turning position, wit out itbeing necessary to switchto firm to stabilise the vehicle. Thus, the limits for switching tofirm on the steering wheel return are higher than when turning,and overshooting the straight line posit~onwhich always happens,

i s also filtered.

The limits for switching to firm based on speed are multiplied btwo during the phase when the steering wheel is returning t o t estraight line position and for a ossible maximum overshoot of 170

The straight line position is saif

to have been overshot when thesteerng wheel passes through this point a t a speed greater than130

per second. If, when returning the steering wheel t o thestra~ghtlineposition, a limit for switching to f ~ rmis exceeded, thesoft state will be reinstated when the value becomes less than thisli it d ft d ti


55/78

2- Accelerator pedal

After the ignition has been switched on, the vehicle speed musthave exceededS kmlh once in order to switch tothe firm state.

If the rateof change of the accelerator pedal is greater than a limitwhich is a function of thevehicle speed, the suspension will switchto the 'firm' sate for:

l 2 ifthe vehicle speed 140 kmlh pedal released orif the vehicle speed

>

140 kmlh pressed down

The limits for switching to firm are different depending onwhether the accelerator pedal i s being pressed down or released.

Note: In the sport position, each limit for switching to firm i sdividedby 1.5 and the timer for returning to soft ismultipliedby 1.3.

Itshould be noted that the higher the speed, the higher the limitfor switchingto firm(parallel relationship)


56/78


57/78

ACCELERATOR LIMITS(RELEASING)(Normal position)

FIRM

Accelerator


58/78

Considering the vehicle acceleration

if after

a switch to f irm caused by the accelerator, the acceleration or

deceleration of the vehicle is greater than four pulses in 512 ms = 1/2 persecond , the firm position is maintained for the whole time during whichthe limit is exceeded (3 pulses in 512 ms) with a minimum duration of 0.8seconds.

Example:

The vehicle is travelling at 36 kmlh which correspondst o 50 pulses persecond and 25 pulses1500ms. If,during the next 500 ms, the speed sensorsends28 pulses (3 additional pulses), the vehicle is ten travelling at:

in other words, 4.3 kmlhmore than before. Therefore, inone second, thevehicle has acceleratedby4.3 2 = 8.6 kmlh. This is not sufficient tomaintain the firm position; the computer would have had to receive moreth 28 l i th t 500


59/78

Features Fault l Effective

:

stroke l

Fault

---------------

I

Throttle

: Throttle j

SC I closed

100

steps Open I

oc :

J

l

l

I

i

I

~ o ~ t e p s l

.

l

4

5

3

245

1

I I

l

l I

1

l

l

:

V

ref-min tolerahce

V

ref-max

I Ref-diap

Zk Acc


60/78

C - SWITCHING TO FIRM BY REACTION

Body movement

The vehicle speed must be greater than 10 kmlh and themovement (attach or release) must be greater than a limi t as afunction of the vehicle speed.

The limits are different depending on whether the movement is in

the 'attach'direction or the release' direction.

The suspension wi ll return t o the soft state when the amplitude ofthe movement is less than a limit value and after a 0.8s timer.

Note:

n the sport position, the limits for switching t o f i rm as well as thetimer remain unchanged.

BODY MOVEMENT LIMITS(ATTACK)(Normal position)


61/78

BODY MOVEMENT LIMITS (RELEASE)(Normal position)

Frontsuspensionmovementmm)


62/78

Features

Wheel impacts

If the movement speed i s greater than 0.3 mls, the limits take the value of60 mm for 0.4 seconds.

Uneven roads

If the limits take the value of 60 mm for 0.4 seconds, and if this occurs morethan three times in three seconds, the limits takes the value of 60 mm forthe next two seconds.

The wheel impact and uneven road functions are not applied:

If vehicle speed > 159 km/h

the steering wheel angle is greater than half the 'firm'limit for the steering wheel angle at the consideredspeed.

Example: The vehicle is travelling at 120 kmlh


63/78

V - VEHICLE ANTI-JOLT

A VEHICLE LEVELLING

We have seen that when the supply to the computer i s cut, thesuspension is in the "Firm" position (Uelectrovalve= 0).Therefore the additional sphere i s isolated.

If the pressure in the main spheres varies (passengers getting in orout, loading drunloading) a pressure difference with respect tothe additional sphere appears.

When the ignition is switched on, as the additional sphere isconnected to the circuit, the pressure difference translates as ainflux (P additional > Pmain) or a reflux(P additional< Pmain)of fluid in the suspension cylinders, which suddenly alters the rideheight of the vehrcle and causes the vehicle to jump.

ROLE


64/78

- SUMMARY OF OPERATION

+ Ignition

Doorcontact

+ Ignition

IElectrovalvecontrol

Doorcontact

t l0mins

ledrovaive

3 s

.

Qs .

I


65/78

then it:

Reinitialises thecounters

registers, etc...

Illuminates the central warning light for three seconds orcausesit to flash for ten seconds a t a frequency of 1 z if afault is memorised.

C SELECTING THE DATA TABLES

The computerhas in i t s memory the tables of parameters for allthe vehicles which can be fitted with hydractive suspension.

When initialised, the computer reads a code which tells itwhich

table of parameters it should use.

If this code does not exist or i s wrong, the computer systematicallychooses the table o f parameters of the

XANTIA

vehicle andswitches the warning light on permanently.


66/78

AUTO-DIAGNOSTIC

I - GENERAL

The auto-diagnostic has been designed with the aim of improvingreliability and preserving

automat~c

operating for as long asposs~ble

Where it is impossible to control the electrovalves (computer broken,electrovalve connector disconnected, supply voltage too low), thesuspension is in the "firm" state hydraulically. On the other hand, forsensor faults, the suspension is maintained in the "supple" position.

1 Steering wheel, accelerator sensors, electrovalves, computerThere are two types of diagnostic:

By coherence of the signals between themselves.

3 Electrovalves


67/78

3 Electrovalves

The two electrovalves switch to the "firm" position.

4 - Computer

Attempts to reinitialise the computer result in the suspensionswitching to firm for a few seconds.

CMEMORISING FAULT CODESFaults are stored in a non-volatile EEPROM memory (faults arenot erased when the battery is disconnected).

D - CHECKING THE SYSTEM

An after-sales testunit and the suspension computer can beconnected in two different ways:

m Slow rate with coded signals with the OUT 4097Tor OUT4120 Ttools


68/78

arameters: steering wheel angle, vehicle speed,patteryvoltage....

With the behicle stopped, the tester can force thecomputer to operate an electrovalve anda warninglight.

These two functions therefore aloow a compltefunctional test of the suspension system to be carriedoutwithout having to work on the vehicle wiringloom. This test can be static or dynamic.

Computer identification

This gives the hardware and software versions, thecomputer parametersand i t s serial numbers.

Loading theparameter table selection coderemotely


69/78

EMERGENCY

STRATEGY

ANNULLED OR

VALID.

COUNTER

FAULT

U

battery

within

range

11.5V-16V

_

0.5Vfor2s

relaunch

att emp t every

30

S

relaunch

att emp t every

30

S

EMERGENCY

STRATEGY

firm

suspension

firm

Suspension

firm

VALIDATION

60

1

9

TEST Y

SIGNAL

COHERENCE

ELE

C.

TES

T

X

X

X

DETECTION STRATEGY

U b c 1 1V fo r2 s

u b > 16.5Vfor 2 s

Electrovalve control

incoherance < 10 ms

during full voltage

control o f 500 rns


incoherence for 500 ms

ANOMALY

DETECTED

battery voltage

outside range

microscopic

supply

breakage

FUNCTION

TESTED

SUPPLY battery

or earth

ELECTROVALVE

FAULT

CODE

DIAG.

WITH

CODED

SIGNALS

53

Front EV)

31

Rear EV)

3

2


70/78

FUNCTION

TESTED

STEERING

WHEEL

PRESSURE

SWITCH

FA ULT

CODE

DIAG.

WITH

CODED

SIGNALS

23

2 1

ANOMALY

DETECTED

Open circuit

n o t w o r k i n g

short circuited

open c i rcuit

short circuit

DETECTION STRATEGY

I

measured

> I

ef max

I

measured < I re f m in

fo r

if

Ve h Sp < 100 kmlh

afte r ignit ion, st. wheel

angle 6.4 for 1 km or

having had a st. whee l

an le > 6.4Oonce:

l

t. W eel angle .4

f o r 3 k m

if

V > 100 kmlh, n o

detect ion

F = l a c c e l > l 5 % f o r

10

S

speed

>

30 kmlh

accel . no t at faul t

speed

>

30 kmlh

no brake in fo

3

decels o f 0.469 in 1 S

ELEC.

TEST

X

SIGNAL

TESTBY

COHERENCE

X

X

X

VALIDATION

4

3

5

5

EMERGENCY

STRATEGY

automat i c

suspension

automat i c

suspension

EMERGENC

STRATEGY

ANNULLED O

VALID.

COUNTER

FAULT

I ref min

15

and no spped signal

for 30

speed O f f 0 kmh

n 512 ns (V > 0 krnlh).

Vl5

speed>30 krnlh and no

transition in the 5

followin the brake

l

witc signal

V signal

>V

ref max

V signal< V ref rnin

for

2

ELEC.

TEST

X

TESTBY

COHERENCE

X

X

X

-. .------------.----------.-------.----------------

VALIDATION

5

5

1

EMERGENCY

STRATEGY

V = 100 km/h

automatic

suspension

automatic

suspension

EMERGENCY

STRATEGY

ANNULLED

OR

VALID.

COUNTER

FA

ULT

signal return

coherent for

20s

movement

angle

measured >

steps

signal return

within range

for 20

signal return

w~thinange

for

2

sand

speed

=

MPH


72/78

VALIDATION

10

ELEC.

TEST

X

X

DETECTION STRATEGY

interna l watchdog

EEprom Check sum

te st EEPROM erasu re

+

readJwrite test

sendinglreceiving test

w hen compu t e r

enerqised

tatu us I npu t w es t

f o r 2 S

Electrovalves no t

cont rol led

EMERGENCY

STRATEGY

reset ip

f i rm susp.

if

V>40

k m l h

f unc t i on

no r ma l w he r e

~ o s s i b l e

fau l t codes

em i t t ed

y

w a r n i n g l i g h t

f i r m

suspension

TEST

IGNAL

Y

COHERENCE

X

X

ANOMALY

DETECTED

p r o g or # p

f au l t

EEPROM

m e m o r y f a u l t

d ~ a g . ~ n e

tlectr valve

con t rol stage

shor t c i rcuited

or open c i rcu i t

FUNCTION

TESTED

COMPUTER

EMERGENCY

STRATEGY

ANNULLED O

VALID.

COUNTER

FAULT

Status

I npu t f o r 2

o n th e 2 stage

FAULT

CODE

DIAG.

WITH

CODED

SIGNALS

54


73/78

- COMPUTER CONNECTIONS

WHITE CONNECTOR

1 - Positive supply of front electrovalve

2 - Positive supply of rear electrovalve

5 Diagnosticline

6-

Tailgateswitch earth signal7 - ~ o o rswitches earth signal

8 - Earth1 - Control through earth of test light

11 - Vehicle speed information

12 - Normal rule (earth)/sport rule( openV)signal

13 - Steeringwheel sensor-

14 - Positive supply of illumination of switch light in sport" position

15 - Earth

DASHBOARDLIGHTOPERATION


74/78

I l l DASHBOARDLIGHTOPERATION

It is supplied directly on the after ignition side 12V) andi s

controlled on the earth side by the computer.

m Ignition switched on the light lights up for three

seconds

Presence of a fault the light flashes for ten seconds a t afrequency of 1 z when driving or when the ignition is

switched on after a shorter initialisation than previously

= 1S).

m Ifthe microprocessor

i sfaulty light permanently

on


75/78

EMERGENCY

STRATEGY

suspension

firm

suspension

f irm

Suspension

f irm

VALIDATION

60

1

-,

EMERGENCY

STRATEGY

ANNULLED OR

VALID.

COUNTER

FAULT

U battery

within

range

11.5V-16V

0.5VforZs

relaunch

atte mpt every

30 S

relaunch

atte mpt every

30

S

ELEC.

TEST

X

X

X

FUNCTION

TESTED

SUPPLY battery

or earth

ELECTROVALVE

SIGNAL

COHERENCE

ANOMALY

DETECTED

batter voltage

J

utsi e range

microscopic

supply

breakage

FAULT

CODE

DIAG.

WITH

CODED

SIGNALS

53

(Front EV)

31

(Rear EV)

3

DETECTION STRATEGY

U b< l l V f o r 2 s

Ub>16 5VforZs


incoherance

100 kmlh, no

detection

F

=

1accel>15% for 10

speed > 30 kmlh

accel. no t at fau lt

speed

>

30

kmlh

no brake info

3 decels of 0.469 in 1.5 S

ANOMALY

DETECTED

Open circuit

no t working

short circuited

open circuit

short circuit

FUNCTION

TESTED

STEERING

WHEEL

PRESSURE

SWITCH

TESTIGNALY

COHERENCE

FA ULT

CODE

DIAG.

WITH

CODED

SIGNALS

3

21

VALIDATION

4

S

5


77/78

EMERGENCY

STRATEGY

V

=

100 k m l h

au tomat ic

suspension

au tomat ic

suspension

EMERGENCY

STRATEGY

A N ULLED OR

YI LID

COUNTER

FAULT

signal return

coherent for 20

movement

ang le

measured >2

steps

s ignal re turn

. wi t h in range

fo r 20

TEST

~ G ~ ~ ~Y

COHERENCE

X

ELEC.

TEST

X

VALIDATION

5

1

5

10

DETECTION STRATEGY

accel

>

15

and no spped s ignal

f o r 3

speed dro p of

3

krn/h

in

512 rns V

>

30 krnlh).

V e 5 k m / h f o r 28

fo l low ing d rop and

accel >l5

speed>30 kmfh and no

t rans i t ion in he 5 S

fo l low in the b rake

f

witc signal

Vs ignal >V ref max

V signal< V ref rnin

f o r 2 s

ANOMALY

DETECTED

l i nk in o p e n

circuit or short

circuit

sensor bro ken

ope n c i rcu i t

b roken

short circuited

op en c i rcu i t

broke n shor t

circuited

FUNCTION

TESTED

VEHICLE

SPEED

BODY

MOVEMENT

ACCELERATOR

FAULT

CODE

DIAG.

WITH

CODED

SIGNALS

24

25

22


78/78

FUNCTION

TESTED

COMPUTER

FAULT

CODE

DIAG.

WITH

CODED

SIGNALS

54

ANOMALY

DETECTED

p r o g o r mp

f a u l t

EEPROM

memory fau l t

d ~ a g . ~ n e

t ectrOva ve

contr o l s tage

circuited

or open c i rcu it

DETECTION STRATEGY

in te rna l watchdog

EEprom Check sum

test +

EEPROM erasure

+ r e a d h r i t e e s t

sendingheceiving test

when computer

energised

@'Statusm@' Inputwest

f o r

2 S

Electrovalves n o t

contro l led

ELEC.

TEST

X

X

SIGNAL

TEST

BY

COHERENCE

X

X

VALIDATION

1

1

EMERGENCY

STRATEGY

rese t 1p.

fir m susp.

if V>4 k m l h

f u n c t i o n

n o rm a l w h e re

possible

f a u l t codes

e m i t t e d b y

w a rn i n g l i q h t

f i r m

suspension

EMERGENCY

STRATEGY

ANNULLED OR

VALID

COUNTER

FAULT

Status

Inpu t fo r 2

o n h e 2 stage

hydractive citroen official training manual

Documents