TECHNICAL TRAININGCONSULTANT TECHNICIAN MODULE B7 Hydractive I XM Hydractive II X M Xantia DOCUMENT REF No: 6.2.304 June 2001 DEALER Q U A L I T Y DEVELOPMENT DIVISION HYDRACTIVE II SUSPENSION INTRODUCTION The choice of spring and damping settings of a vehicle's suspension is based on two main triteria. I - COMFORT The flexibility and the damping rate are defined so as t o isolate the occupants of the vehicle from impads and vibrations by using an oscillating frequency btween 0.9 and 1.2 Hertz and by limiting vertical accelerations to 0.25 g (2.45 mls2). I1 - ROAD HOLDING Like competition can, hardsuspensionand anti-roll adjustments are required to limit the movement of the body and to make the tyres work in a precise manner. The aim of this system is to obtain comfortable suspension whilst having the ability to modify the suspension and anti-roll adjustments automatically when the vehicle i s in a limit situation which requires hard adjustments(quicksteering, tight bend, heavy braking), which corresponds to approximately fifteen per cent of the time. Therefore, there are two suspensions in one allowing "comfort" and "sport" behaviours to be set automatically depending on the driving conditions. - I - PRINCIPLE OF HYDRACTIVE SUSPENSION For a vehicle t o be comfortable, its suspension must be set t o be supple in flexibility, damping and anti-roll. These settings do not allow the movement of the vehicle t o be controlled properly when disturbed. In this case, firm suspension is needed which reduces comfort. Standard suspension is a compromise defined as a function of the type o f vehicle (family or sports). The role of hydractive is t o offer these t w o types of settings and t o select the ideal solution automatically as a function of the driving conditions: No disturbance : supple suspension promoting comfort, Disturbance : firm suspension to control the movements o f the vehicle. Switching from one state t o another is controlled by a computer wi-lich, as it is informed of the driving conditions by sensors, acts on the suspension settings. . DISTURBANCE T By default the suspension is supple. When disturbed, the suspension switches to firm. When the disturbance passes, the suspension switches back t o supple after a short time delay "T" (variable from one t o three seconds). the overall response time of the system is extremely short(less than 51100th of a second). EVENT - VALUE MEASURED SENSOR Bend Angle of rotation Steering wheel Steering wheel turned Rotational speed Steering wheel Request for power Engine brake Development speed of the accelerator pedal Accelerator pedal Braking Front brake pressure Brake . e a computer programmed with new laws: m for switching to the "soft" and "firm" states: in the "sport" position. EVENT - - - 111 VALUE MEASURED - Height variations Compression extension Acceleration Deceleration Speed variation per second SENSOR Body movement Speed (orDistance) IMPROVEMENTS MADE TO HYDRACTIVE I1 a front electrovalve and a rear electrovalve : each of these i s directly integrated into one of the stiffness regulator. The suspension will therefore become harder before the vehicle has moved. the thresholds for switching from the "supple" stateto the "firm" state are more lower*.Switching t o firm by anticipation The computer win switch to the firm position as a function of the events which risk compromising the stability of the vehicle. the "firm" state is no longer permanent and in the "cornfort"'position. this strategy prevents a sudden change in behaviour when switching from onestate to the other. Switching t o firm by reaction: The computer switches to the firm position as a function of the reactions of the vehicle. . switching to "firm" occurs for a steering wheel angle greater than 33 degrees. switching to "firm" occurs for an angle of 22 degrees and this state is then maintained for l. In the same conditions.2 seconds.REMINDER A mechanical spring (helical.. I - VARYING THE SPRING SETI1NG A . On the motorway at 120 kmlh (75 mph). in the "auto" position. .6 seconds. a t 50 kmlh (31 mph). switching t o "firm" occurs for a steering wheel angle of 120 degrees (a third of a turn of the steering wheel) when in the "auto" position and the time delay is 1. torsion bar .2 seconds when the steering wheel returns to an angle less than 33 degrees. On country roads or in town..) is characterised by its spring constant which i s defined as its material deformation as a function of the force applied to it. switching from supple t o "firm" occurs for an angle of 80 degrees and this time the time delay is 1. in the "sport" position. In the same configuration.* Example of the new laws for switching from the supple state t o the "firm" state.6 seconds. in the "sport" position. this state is maintained for 1. B . Application By adding an additional sphere or not to the main circuit. Therefore. This is the solution used t o obtain the "Soft" and "Firm" states. SOFT - . t o alter the setting of a hydropneumatic suspension system for a given load. thevolume of nitrogen V has t o be altered.THE HYDROPNEUMATIC SPRING Nitrogen Membrane The elastic element consists of a mass of nitrogen of which t h e pressure and volume vary as a function of the force F applied to the piston Fluid Ui Piston . the volume of nitrogen is modified. the volume of nitrogen in the spheres i s reduced and therefore the suspension is harder. Likewise. when the suspension is compressed the volume i s reduced thus reducing the flexibility.Comments: When the vehicle is loaded. This is the reason why the hydropneumatic spring has a variable spring constant due to i t s constitution when the load changes or duringvibrations. Hydractivesuspension allows the flexibility to be varied for a given load. . The inlet or outlet of the fluid in the cylinder does not modify the flexibility only the height by modifying the distance between the membrane and the piston (provided that the suspension is not a t i t s limit). . B- "FIRM" POSITION The fluid only flows through A. A ."SOFT" POSITION The fluid passes through A towards the main sphere and through A'towards the additional sphere. There is increased damping. Fluid braking is low since the fluid can flow in two ways +damping is low. or not. one of them t o vary the damping.I1 .VARIABLE DAMPING This consists of putting two shock absorbers in parallel and isolating. . as the two elements on the same axle are linked together hydraulically. With hydropneumatic suspension.REMINDER OF HOW STANDARD HYDROPNEUMATIC SUSPENSION WORKS \ - Direction of roll With metallic or pneumatic spring suspension. which explains their rigid mountings (trunnions). when a force is exerted when cornering.111 - ANTI-ROLL A . The anti-roll effect is only performed by the anti-roll bars. the outer wheel compresses i t s suspension which limits the roll. and do not oppose the roll. the fluid from the compressed element is discharged to the extended element and therefore neither the volume nor the pressure vary in the compressed element. .. . low anti-roll can be obtained to optimise comfort (when one wheel passes over a hump..B . "h . - Direction of roll m ... . .. . Thus. . .. The anti-roll function of the suspension element is a t a maximum. the fluid flows from the disturbed element to the other without alfering the transversal height of the body) and hi h anti-roll for violent forces (stability of the transversal heig t). which means that the force is applied progressively and the pressures Pg and Pd are balanced more slowly."Soft" state Vd Shock absorber Dynamic anti-roll is improved by the two additional shock absorbers A' which brake the fluid movement between the two elements.! . J-tObstruction The two elements are isolated since the fluid flow is obstructed.. 1 .:. ..ACTIVE ANTI-ROLL OF HYDRACTIVESUSPENSION The circuit is modified with respect to the standard system in the both states. T Body movement sensor I Diagnostic Rear stiffness regulator control electrovalve regulator E light U ~ o oswitch t : Electrical connections --------- : Hydraulic connections NoPR < 5971 .10 PRESENTATIONOF THE ASSEMBLY I - SUMMARY DIAGRAM Outputs Inputs I Front stiffness regulator control electrovalve SPORT control pi%regulator Steering wheel sensor - Vehicle distance sensor M P Accelerator pedal travel sensor U Braking pressure sensor Light on 'SPORT' switch __I-\ . 11 .of the front sub-frame Bodv movement sensor Front stiffness regulator - 1 - + electrovalve I Behind the cooling radiator at the front left I IRear stiffness regulator + electrovalve I Rear axle pipe - - Dashboard warning light At the top on the right Auto-diagnostic socket Under the dashboard on the front left (with fuse box) . Riqht .POSITION POSITION ELEMENT Computer Ventilated housing on the front right wheel arch under the bonnet Control switch Central console behind the height control lever On the steering column behind the steering wheel Steering wheel sensor IOn the gearbox (tachometricsocket) Vehicle speed sensor Accelerator pedal travel sensor On the pedal arm Braking pressure sensor On the front left of the engine sub-frame . DIAGRAM OF OPERATING PRINCIPLE SUSPENSION SWITCH 7f STEERING WHEEL SENSOR 1I BODY 4CCELERATOR MOVEMENT PEDAL SENSOR SENSOR V 11 11 ~r VEHICLE SPEED SENSOR ~r \' I 5v Sv COMPUTER DOOR SWITCHES 1I BOOT SWITCH 1 TI I . 13 OPERATION OF THE HYDRAULIC PART I - PRESENTATION Parts list 1- Front electrovalve Front stiffness regulator Rear electrovalve Rear stiffness regulator Front height corrector Rear height corrector Front suspension elements Rear suspension elements Priority valve Brake doseur valve Pressure switch . The tightening torque is 3 to 3. Sealing is provided by I S 0 tapered connectors without gaskets. Note that the pipes connecting the suspension elements to the regulators have a large diameter (8 X 10) in order t o reduce load losses and therefore the response time.Filter I .The system differsfrom standard suspension due to the addition of t w o stiffness regulators 2 and 4 (one per axle) each incorporating a n electrovalve.Seat 7 .5 mdaN. I3 4\ \5 1 Coil 6 . B .ROLE This allows the stiffness regulator to be controlled hydraulically according t o the electrical information it receives from the computer.CONSTITUTION Parts list Spring Needle Core Seat User circuit I . II - THE ELECTROVALVE A . .OPERATION I As the coil (5) is not energised. Conclusion: Electrovalve User circuit pressure not activated reservoir activated supply (HP) . Therefore. - 2 Activated postion As the coil (5) is energised. L' The user circuit output B i s therefore connected t o the reservoir C. This causes the needle (2) t o move which comes into contact with the seat (4). the spring (1) presses the needle (2) onto the seat (6). it creates a magnetic force in the core (3). we have : B The user circuit output B is a t the supply pressure A.A t rest The following are connected B A .C . 5V Nominal intensity : 3 A when powering up for 0.5 seconds with the maximum voltage.5 A when holding by disconnecting the supply voltage Maximum cut-out time < 1.8 Q Control frequency : l000 Hz suspension element \ suspension element Hydraulic rese~oir Height corrector . 0.D- CHARACTERISTICS Nominal voltage : 13.8 ms Resistance : 4. Electrovalve .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 .Height corrector B .C-Suspension elements D .Slide valve 4 .Valve 5 - Shock absorbers Hydraulic connections A.111 - THE STIFFNESS REGULATOR A . 18 C- OPERATING PRINCIPLE l ."Soft" state Reservoir -- High Pressure Reservoir I ll Parts list 2 .Body 7 .Height corrector 4 -Valve 9 Priority valve l -Additional sphere 5 -Shock absorbers 6 Rear suspension elements - .Slide valve 8 .Electrovalve 3 . When the electrovalve is energised. the slide valve (3) is subjected to the high pressure HP on one side and to the suspension pressure PS on the other. There is therefore a link between the two suspension elements and the additional sphere. Fluid passes through four shock absorbers (to reach the additional sphere. Since HP > PS. Note: The operation of the valve (4) will be discussed later. the fluid passes through the shock absorbers (5)) -+ soft damping Fluid passes from one suspension element t o the other soft anti-roll When the height correction is in the "Soft" position. the slide valve is locked in the "Soft" position. This gives: Large volume of gas (suspension spheres $ additional sphere) -+ soft suspension. 7 . the fluid passes directly through the shock absorbers (5) and supplies the cylinders (6). - 2 "Firm" state High Pressure Doseur valve -l I . Therefore. the slide valve (3) is subjected to the suspension pressure PSon one side and to the reservoir pressure Pr on the other. Since PS > Pr. +Firm damping Fluid does not flow between the two suspension elements +Firm anti-roll . 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 is broken.ASthe electrovalve is not energised. there is : Small volume of gas (additional sphere isolated) + Firm suspension Fluid no longer passes through the shock absorbers (5) since the additional sphere i s isolated. End Stop 2 .Thrust Rod 3 .111 . e The suspension elements to be isolated for roll. therefore preventing fluid flowing between the two spheres.ROLE This allows: a In the "Firm" state.CONSTITUTION Parts l i s t 1 .Height corrector B .STIFFNESS REGULATOR BALL VALVE A .C-Suspension element . B .Seat Hydraulic connections A . the suspension elements to be connected to the height corrector during correction or.Seat 5 - Ball 6 .Spring 4 . presses against the end stop (1) and releases the ball. 1 2 ? V 5 6 -When the height corrector returns t o the neutral position.3 . since there is no flow. the ball is pressed against the seat (6). The rod (2) compresses the spring (3) and presses on the ball (S). thus closing the connection. locking this a t the base of the valve. When the roll stops. It moves the ball (5) which presses against the seat (4). the upstream pressure is greater than the downstream pressure. 4 2 - 5 When turning in the opposite direction. there is no longer any transverse strain on the vehicle and the ball is released.OPERATION 1 - Anti roll When rolling. the ball is locked whilst the vehicle is rolling. fluid tends t o flow from one suspension element t o the other. As the pressure of the compressed suspension element is greater than that of the extended suspension element. the thrust rod (2). under the action of spring (3). . Inlet admission Since the area around the thrust rod (2) where fluid can pass is small. 3 - Outlet correction Under the effect of the fluid discharged by the suspension elements.it is therefore locked in this position and does not prevent the fluid flowing. the ball presses against the thrust rod (2). . A t the end of the correction. the flow is zero and the ball is released. This then presses against the end stop (l). Monitors all the system components: Sensors. electrical links. as a function of the information from the various sensors. Monitors the operating software Should a hardware or software fault occur: Ensures maximum possible safety Switches to a downgraded operating mode (emergency strategy) Warns the drivers by illuminating a warning light Carries out an auto-diagnostic of the essential elements and functions . unit itself. II. braking and the amount the pedal is pressed down a$ weH as by analysing the vertical movement of the body (amplitude of the movement). The state changes t o firm when the threshold is exceeded.COMPUTER A - .25 ELECTRONIC OPERATION I - PRINCIPLE The suspension has two stiffness states and two damping states. steering wheel speed. Changes in state are controlled by anticipation by one of the four parameters of steering wheel angle. Power supply. actuators. returning to the supple (or soft) state occurs when the value of the parameter is once again lower that the threshold and after a time delay has elapsed. ROLE Controls the stiffnes_sregulator electrovalves so as t o switch the suspension from one state to another (supple or firm). The parameters from-the sensors are compared with variable thresholds as a function of the vehicle speed. The heart af the computer consists of two TEXAS INSTRUMENTS 16 kB and 4 kB microprocessors.5 to 11 V + no functions work except element protection and auto-diagnostic 11 to 16 V 4 all functions work 16 t o 24 V no functions work except element protection and auto-diagnostic 16 to 18 V + 2 hours before destruction 18 to 24 V 1 minute before destruction Above 24 V + no functions work Consumption: When operating. without electrovalve consumption + < 500 mA When not operating (ignition off and after self-levelling timer). doors and boot closed < 2 mA W h e n not operating. which can be disconnected in any order.5 V+ 8 7. doors andtor boot open 4 < 100 mA . The link to the outside is provided by two connectors each with fifteen channels (one white and one black).B - CONSTITUTION This i s a sealed unit into which are fitted the various electronic components. C - CHARACTERISTICS operating temperature Storage temperature Operating volta e: no unctions work o to 7. Integrated circuits monitor the supply voltage and protect the computer. The control transistors of the electrovalves (called "intelligent") are capable of detecting open circuit and closed circuits. computer i s earthed (link 2 + 1 made).SENSORS A . + + . If terminal 12 of the computer is "open" (link 2 1 cut). + Lights I B14 812 I M P U E I I I C 0 R I I Note: In *SPORTm.5 Vismeasured at terminal B12 of the computer. this applies the "Comfort" suspension rule. When the switch is in the "Sport" position. open in the "Sport" position. The switch is closed in the "Normal" position. 2 - - Constitution Operation . this applies the "Sport" suspension rule. If terminal 12 of the. The illuminating light of the switch unit is dimly lit by the light due to the resistor integrated into the unit. the light is brightly lit due to a from terminal 14 of the computer..111."SPORT" CONTROL SWITCH 1 - Role This allows the driver t o impose the "SPORT" rule. . b) Position It is mounted onto the tachometricsocket of the gearbox.B . Principle of Hall effect -Q.Hall sensor 3 .EATON SPEED SENSOR a) Role This sensor supplies an electrical signal which is proportional t o the rotational speed of the secondary gearbox shaft.Bearing 4 .Drive This sensor is a Hall effect pulse generator. c) Operation 1 . and therefore t o the vehicle speed.Polar wheel 2 . The essential element of this system is a plate of 1. provided that the two simultaneous conditions of electric current and magnetic field are satisfied). When a S-N magnetic field is applied a t right angles to the plate. Operation LsJ circuit Speedo cable 2- Gearbox ' + after ignition (12V) T k Thg polar wheel. causes a north pole. a very low Hall voltage of 0. (This comes from the deflection of the A-B current lines by the magnetic field. If there is no magnetic field.. no voltage is obtained between-the equidistant points E and F. south pole. . north pole. when rotating. The current supplied by the slice therefore changes direction alternately.001 volts i s obtained between points E and F. which is used for amplifying the signal. supplies a square signal to the computer of which the upper limit corresponds to the direction of the plate current and the lower limit corresponds to the inverse direction of the plate current as a function of the pole passed in front of it. etc. A current passes over this plate between points A and B.2mm length. to pass success~velyin front of the Hall plate.The integrated circuit. of which the frequency is proportional to the speed We know that the sensor supplies: .Eight pulses per revolution of the polarwheel (eight pairs of poles) . ~ a c time h the vehicle travels 20 cm.2 m travelled +20 cm (1 m15 ulses). 7-2 km/h Note: the sensor output signal is measured with a voltmeter in the "direct currentn position. All that is required now is t o count the number of pulses per second t o determine the vehicle speed.d) Calculating the speed The sensor supplies square signals. the vehicle i s travelling a t 36 krnlh. if the sensor supplies 50 pulses per second. 50 pulses 4 50 X 20 cm = 1000 cm = 10 metres The vehicle is therefore travelling at 10 m/s 10 m/s = 10 X 3600 = 36 000 m/h = 36 kmlh Therefore. the voltage reac! t es its maximum value (pulse). 50 pulses +36 km/h 100 pulses +72 kmlh 10 pulses i . Therefore. one pulse corresponds t o 0. . Example The sensor supplies 50 pulses per second.Five pulses per metre travelled. The sensor is fixed and the phonic wheel turns with the steering wheel.Optoelectronic sensor 2 .C - STEERING WHEEL SENSOR 1 - Role This generates signals which enable the computer to define the angle and the speed of the steering wheel.Double emitting part 3 - Double receiving part 4 . It consists of two light emitters. 2 - Constitution It is a double optoelectronic sensor. Partslist ' 1 . two receivers and a phonic wheel with windows.Phonic wheel . indexed in rotation. The phonic wheel and the sensor form a compact Valeo make unit. Its reverse conductivity is proportional to the il umination. by simplif ing. the displacement of the phonic wheel can be turned into signals depending on whether there is a window or not. it can be seen that the diode conducts when it is il uminated and does not conduct when there is noillumination. r Light Junction 9 Inverse voltage: l0 V 0 10 20 30 Radiation nWICM3 Output wires Therefore. Y b) Application of the optoelectronic sensor If a photodiode is fitted opposite a light source and if a phonic wheel with windows is passed between these t w o items.3 - Operation ) Reminder of a photodiode A photodiode is made from a PN junction which can be illuminated externall . . Receiver C . .33 We therefore have: A B ~ O O O O 0 0 0 L- O O 0 0 0 O -c A .Displacement S .Emitter B .Output One complete steering wheel revolution = 28 pulses C) Electrical diagram Optical element A The sensor is a double one so as to obtain better precision and to allow the computer to determine the direction of rotation of the phonic wheel.Phonic wheel D. the voltage is practically zero.. (S11 A1 (S21 V B1 B13 . % 9. The two sensors are offset by 114 step (phase quadrature) so that the direction of rotation can be determined and so as t o give better precision. . the correspondin transistor (C) is blockea switch + open.34 d) Operating principle > C 0 M P 0 U T E R @ NI0 + 5Vsupply NI5 - X 9.5 V N9 .5 Vfrom the computer. The corresponding output (S) is therefore connected to the negative +. When the phonic wheel breaks the light beam pointing a t a photodiode. The computer supplies the sensor with cl . The two output transistors of the sensor are like two switches C1 and C2. contact made. ! When the window lets the light beam hit the photodiode. C2 Jo- STEERING WHEEL SENSOR 0 + 5 volts. The correspon ing output (S) is therefore "open" +-there is a voltage of 9.5 A3 . this conducts and unblocks the corresponding transistor (C) +. Therefore. . As the wheel has twenty eight windows. Offset Sensor l I:: . Sensor 2 Output codes The steps read by the computer are therefore the output codes.5 - Processing of the signal by the computer a) Work done by the computer Interprets the signals from the sensor (number of steps) Determines the direction of rotation Determines the straight line position Calculates the angle of the steering wheel with ~espectt o the calculated straight line Calculates the rotational speed of the steering wheel Compares the values of the rotational speed and the angle found with the switching t o firm thresholds of the computer. or not. we have: Note that for one step of the phonic wheel. there are four output codes. the two elements being offset by a 114 of a step (phase quadrature). the precision is one code step for : . I I I I I I l I I l The precision is therefore multiplied by two due t o the double sensor. b) Determining the number of steps P We have seen that the sensor is double. Controls. switching of the suspension t o the "firm" state. As soon as the steering wheel leaves this sector.5" with respect t o this point is therefore created. and calculates the average of the steering wheel positions sampled every 1.c) Deterining the direction of rotation As the computer knows the logical order of the codes. it is said t o be "not calm". it just has t o compare the new code with the old code t o work out the direction of rotation. If the steering wheel is "calm".6 metres.5" with respect t o a zero point for at least one second.Left 0 New 1 1 Old 1 +Right Determining the straight line Definition of the "calm steerinq wheel" notion The steering wheel is said to be "Calm" when i t s movements remain within a sector of + 6. The computer then memorises the distance travelled in this sector and the calculated average. the computer starts measuring the distance travelled. Definition of the zero point PO The first point PO corresponds t o the position of the steering wheelwhen the speed of the vehicle reaches 30 kmlh. A sector of + 6. d) 0 0 New 1 Old 0 -. (The conditions in which the computer updates the straight line position will be discussed later). . Definition of distances The following are known as: D 4 [BP 4 distance over which the computer has calculated the straight line. distance travelled with the steering wheel calm Application: Steering wheel not calm Steering wheei calm 1 Steering wheel calm 2 New position STOP Distance DP measured Average calculated D memorised Average position After one second + counter to 0 -+ distance DP measured +average position calculated . a new sector of 13" centred about PO i s created and therefore the steering wheel becomes calm. the distance travelled counter returns to zero and the computer calculates the average of the steering wheel positions in this sector.The new position of the steering wheel becomes the new point PO. After travelling a distance DP = 550 metres with steerin wheel calm +steering wheel position updated and D becomes equa t o 550 metres. an update will have t o be done in this sector. Therefore. + Example : distance memorised D = 500 metres. for as long as t h e steering wheel is calm. If DP > D +LD updated. when t h e distance travelled w i t h the steering wheel calm DP i s greater that the memorised distance D at the time o f t h e last update.. The computer compares the distance travelled DP in this sector with t h e memorised distance D. above 3000 metres. only when t h e steering wheel is calm. a t DP = 600 m +and D = 600 m etc. or Steering wheel n o t calm after 51 1 m(DP > D) Therefore.. therefore the distance memorised is D = 0. updating will occur every 50 metres. t h e straight line position will be updated every 3000 m. Therefore.Updatinq t h e straiqht Iine The computer memorises t h e straight line osition LD (average of t h e Sum of the num er o f steerinq wheel positions positions in t h e sector: number of acquisitions and t h e distance D over which it has been calculated. t h e memorised distance D increasing by 50 m. 9 The steering wheel leaves the current 13" sector +steering wheel n o t calm.ised LDo is the position of t h e steering wheel when Vveh = 30 k m l h (PO). A n e w straight line LD will be memorised (average o f the positions in t h e sector) as well as the distance D over which it was calculated if one of these t w o events arises: e Distance travelled with steering wheel calm DP more than 50 metres than t h a t memorised D: DP = D 50. Example : t h e last update occurred a t D = 510 m. . Then. g The first straight Iine memor. if not (DP < D) +LD not updated. the computer determines its straight line when t h e steering wheel is calm for the longest distance. The straight line will b e updated if : + Steering wheel calm for DP = 560 m (D SO). Note: The maximum distance D = 3000 m. 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 sensor in one second. NOTE: The ECU accepts rotational speed signals of up to 2. .5" per milli-secondfrom the steering wheel sensor. Any value above this threshold has the same effect. SYNOPTIC FOR DETERMINING STRAIGHT AHEAD POSITION VS = 18 MPH A +6.5" around PSW DT = 0 E Time = 1s SA = Average PSW acquired D = DT Steering PWS Learning the Sector? 1 'calm' Steering 'calm' Computing DT and PSW every 116 m 4 + DT = 50 or DT = 3000 m + SA = Average PSW acquired D = DT PSW = Position of Steering Wheel SA = Straight aheadposition D = Distance over which SA has DT = Distance travelled with VS = Vehicle speed been calculated steering 'calm' . Role This enables the computer to know the position of the accelerator pedal. .8 V supplied by the 0 (pedal up) Cursor in any position + Vs = Ve X % travel The protective resistor (1) limits the intensity when faulty connections are made (E. Parts !ist 1 .Receiving track 3 -Cursor - 4 Resistor ACCELERATOR SENSOR The output voltage Vs depends on the position of the cursor Cursor up -.ACCELERATOR PEDAL TRAVEL SENSOR 1 .D .= + 3.Operation It consists of a variable resistor. there would be a short circuit). of which the cursor is controlled.g. 2 - Constitution .Protective resistor 2 . inversion of the wires on N1 and N2 if the cursor is down.Vs = Ve with Ve = computer (pedal fully down) Cursor down +Vs .bythe pedal. Divide this actual stroke into a certain number of steps. b) Dividing the sensor stoke into a number of steps .Characteristics Main resistor Protective resistor 4 . Deduce the actual electrical stroke of the sensor from this information. Check how many steps are covered in 32 ms (speed a t which throttle is closed or opened) when the driver operates the accelerator pedal. I I I l I I ! V ref-rnax .Computer processing of the signal a) Work performed by the computer Reads the sensor voltage with the accelerator pedal in the 'throttle closed' position and the sensor voltage with the pedal in the 'throttle open' position. Compare the speed a t which the throttle is opened or closed with the limits for switching the suspension to firms.I Fault I I : jSC I Throttle closed I l I I I NoSteps I l I I I 8 U I L It I I I $l31 I I l I I l I I I ! I I l I I I I I I V ref-rnin j l I l I I I 18 t I I I I I . I l I I Effective stroke 100StePS Fault l : Throttle Open I I I I l l I l I l I I a 225 I I I oc l I I I I I I I 2 I3 245 I I I . I I I I I I I l I I I I I I I I I 1 I I I .3 . Give the order to swtich the suspension t o firm or not. with the sensor fitted. '4 In reality. . it takes this as the real 't rottle open' value.meterslider an considers i t t o represent the throttle closed position. the computer knows how to adapt t o all situations. it adds 100 steps for the minimum compulsory effective stroke which gives a voltage value for the 'throttle open' position.0196 V per step. B R F: Likewise. thus giving a minimum effective stroke of 100 steps. the throttle closed position should have been between 10 and 30% of the total theoretical electrical stroke.divided into 255 ste s which gives a value of 0. When the driver accelerates for the first time. this was too restrictive and from now on the computer will use a minimum effective electrical stroke of 100 steps for analysing the development of the accelerator pedal. it has a greater effective stoke which it then divides into a certain number of steps directly as a function of the electrical value of one step. From this value. if the voltage is of a higher value than that corresponding t o 100 ste s of mlnimum effective stroke. if the 'electrical distance' is greater than 100 steps. if the driver resses the accelerator pedal slightly when he switc es on the ignition. the throttle closed' should be a maximum of 125 steps.Previously. It is consi ered that. The computer has the total electrical stroke stored i n i t s memory (0 to 5V. the corn uter reads the voltage from the potenti0. The process is as follows: When the ignition is switched on. When the computer has read the two values of 'throttle closed' (pedal up) and 'throttle open' (pedal down). the computer will correct the 'throttle closed' position when it receives a voltage value which is lower than that read when the ignition was switched on. 6V . . It The computer takes these values of 1.41 0.0196 V per step.1.throttle open = 255 steps * A step = . In theory: throttle closed = 125 steps + 2.09V =Short circuit fault zone = Open circuit fault zone The driver swtiches t h e ignition on: .96 =4.92 V (throttle open).The computer receives a volta e of 4.6V 4.54 V (throttle closed a t 125 steps) + 1.6 V in o n e direction or the other.4. However.96 = 3. The effective stroke is therefore n o w between 1.41 V (throttle open a t 255 steps).96 = 2.5V . . the fualt zones are entered. if the voltage exceeds t h e 0.The driver presses t h e accelerator pedal and the computer receives a voltage o f 4.0196 V f o r one step.96V (throttle closed) and 3. which gives 128 steps at 0.35 steps .96 therefore has a minimum effective stroke o f 100 steps between 1.45 + + 1.51 V. . thus 1.96 (the driver had opened t h e throttle slightly by pressing the accelerator pedal when he switched t h e ignition on).47 V. It can be concluded t h a t t h e number of steps o f the effective stroke can be greater than 100 every time the slider voltage approached 0.5 V threshold.96 V.96 < 2. 4.The computer receives a voltage 0. 1. Now.6 V threshold o r t h e 4.0 t o 0.96V.45 V .47V > 4.47 V (throttle open).5 (the driver had n o t P opened the throttle complete y [pedal fully down] t h e first time).233 steps 2. The effective stroke will be increased once again if: .47 < U < 4.Example: 255 steps divided by 5 V gives a value of 0.47 .92 V. 4.96 V (throttle closed) and 4.47 V as being t h a t o f the actual 'throttle open' position. The computer therefore has available a usable effective stroke o f 128 steps instead o f l00 steps. The computer takes the value o f 4.The computer reads 1.6 < U < 1.5 t o 5 V 100 steps = 1. If P > 35 bar > ''Open -. The computer reads the electrical signal a t i t s terminal N 11 : < 35 bar > earth signal.E .5 V. If P N F .Phonic ring l Emitters . the phonic wheel is rep aced by a phonic ring with 45 teeth. P Parts l i s t 2 . 2 - Constitution It consists of a double optoelectronic sensor of the same desi n as the steering wheel sensor.Receivers 3 . The two optical elements are offset by a 114 of a step (phase quadrature).BRAKING PRESSURE SENSOR This is a pressure switch is closed a rest I Nll B12 B11 It is closed for a braking pressure S 35 bar and open for a braking pressure > 35 bar. however.BODY MOVEMENT SENSOR 1 - Role Allows the computer to define the average height of the body and the movements of the suspension. When a gap of the ring allows the light beam past.3 - Operation The operating princi le is the same bs that of the steering wheel sensor. At the corresponding terminal on the computer. The ring is connected by system of small connecting rods t o the front anti-roll bar. 5. 4 - Characteristics Maximum movement: l80 mm Therefore 1 step 4 6 mm 1 step = 2"4180mm = 60" 30 steps . ? In this case.7 V is measured since it is "open". the corresponding transistor is unblocked and connects the corresponding computer terminal t o earth + a voltage of approximately 0 V is measured. the corresponding transistor is blocked. The rotation of the anti-roll bar causes the rina t o turn and the rotation is detected by the optical element. In the case o the body movement sensor. when a tooth of the ring breaks the light beam. the sensor i s supplied with + 12 V after ignition. .: Calculates the movement by the difference with the average height compares the movement values found with the switching t o firm thresholds of the suspension . Therefore. . The updating formula i s as follows : Have = (Have already calculated = Have 1) - -(Hinstantaneous) + 3 1 32 3i Putting A = Have . . It is updated every 120 ms. or not. .1 . therefore it dete~mines the coded steps and the direction of rotation in the same manner. . he phonic ring has 45 teeth.(instantaneous) Hinst = Have . the it . the precision is 2" per step (360) 45 x 4 c) Determining the average position The average height is the average of the signals from the sensor in both directions. average height (Have) and updates ...-. e Controls. switching of the suspension t o the "firm" state b) Determining the number of steps P The body movement sensor operates in the same way as the steering wheel sensor.5 - Processing of the signal by the computer a) Work performed by the computer Interprets the signals from the sensor (number of steps) Determines the direction of rotation of the ring (leading or trailing) Calculates the displacement speed e Determines .Hinst = difference between average height already calculated and the current height .l + A. . it can be deduced that : Have = . They are used for the anti-jolt function which will be discussed later. 87. The earth s i nal is present when one of the doors or the tailgate is openec? Contacts open. a voltage of 12 V is measured at terminals B6 and . B6 ailg gate switch Door switches .G - THE DOORS AND TAILGATE The aim of the door or tailgate switches is to provide an earth signal to the computer or not.. ELECTROVALVE CONTROL Normally. . .PRINCIPLE . the suspension is "supple" (three spheres per axle) .. Braking +brake sensor Speed the accelerator pedal is being pressed or lifted -. the computer switches to "firm" (two spheres per axle) via one of the following parameters : Steering wheel angle f ( Steering wheel speed ) steering wheel sensor Amplitude of vertical movement in both directions +body movement sensor . . and allow the transversal. '..- IV STRATEGIES FOR SWITCHING TO FIRM A . Control loqic of elearovalves The two electrovalvesire always controlled at the same time : Supple suspension +they are energised Firm suspension +they are not energised Note: The rear electrovalvemust be controlled 10 ms max affer the front electrovalve.pedal sensor All these parameters are a function of the vehicle speed. longitudinal or vertical accelerations of the vehicle t o be determined by anticipation or reaction. . The suspension will return t o soft when the steering wheel angle becomes less than a limit value and after a 1. 13 10 159t-%i-- Vehicle speed (km/h) It should be noted that the higher the speed. t h e lower the limit for switching t o firm (inverse relationship).3.2 s timer.B - SWITCHING TO FIRM IN ANTICIPATION 1- Steeringwheel a) Using the angle of rotation The vehicle speed must have exceeded 30 km!h once and the angle must be reater then a limit which IS a function of the vehicle spee 8. . Note: In the s ort position. each limit for switching t o firm is divide by 1.5 and the timer for returning to soft is multiplied by 1. B STEERING WHEEL ANGLE LIMITS (Normal position) 817 I l I I I I 8 I I I I I I Steering wheel angle (degrees) 20019018017016015014013012011010090 80 70 60 50 4030 20 10- I FIRM I 84 119 87 s31'T - 0 71 33 26 *O 34 4O 10 j 0 69 79 90 100 120 140 . . . . ? The suspension will return t o soft when the steering wheel speed becomes less than a limit value and after a 1.L + .b) Using the angular speed of the steering wheel The turnin speed must be greater than a limit which is a function o the vehicle speed. each limit for switching t o firm is divided by 1.4 s timer.7. Note: In the sport position. .5 and the timer for returning t o soft is multiplied by 1..3. 22 0 1Q .STEERINGWHEELANGLE LIMITS (Normal position) 1605 I I I l I I 600 - I I 1 I 1 I Is5 500 FIRM -. 400Steering wheel angle (degreesh) 300 - 200 -- 100 . the lower the limit for switching to firm (inverse relationship).. 20 " 240 . 40 * 80 120 Vehicle speed (kmth) 160 200 It should be noted that the higher the speed. the limits for switching t o firm on the steering wheel return are higher than when turning. and overshooting the straight line posit~on. wit out it being necessary t o switch to firm to stabilise the vehicle.which always happens. . g c) . f: The limits for switching t o firm based on speed are multiplied b two during the phase when the steering wheel is returning t o t e straight line position and for a ossible maximum overshoot of 170. is also filtered. If. the computer returns t o the soft state and will reinitialise the straight line position. Thus. the soft state will be reinstated when the value becomes less than this limit and after a one second timer. The straight line position is saicf' to have been overshot when the steerng wheel passes through this point a t a speed greater than 130 per second.Specific case of steering wheel centring Through experience. a limit for switching t o f ~ r m is exceeded. when returning the steering wheel t o the stra~ghtline position.Note: If the time for switching to firm using the steering wheel angle is greater than 120 S. The straight line position will not be reinitialised if a speed sensor fault is validated. it has been realised that the steering wheel always returns to the straight line osition quicker than when it moves to the turning position. the vehicle speed must have exceeded S kmlh once in order to switch t o the firm state.2- Accelerator pedal After the ignition has been switched on. If the rate of change of the accelerator pedal is greater than a limit which is a function of thevehicle speed. each limit for switching to firm is divided by 1.3. It should be noted that the higher the speed.5 and the timer for returning to soft is multiplied by 1. the higher the limit for switching to firm (parallel relationship). Note: In the sport position. the suspension will switch to the 'firm' sate for: r l.2 S ifthe vehicle speed < 140 kmlh 1 S if the vehicle speed > 140 kmlh ) pedal released or pressed down The limits for switching to firm are different depending on whether the accelerator pedal is being pressed down or released. ACCELERATOR LIMITS (PRESSING DOWN) (Normal position) Vehicle speed (kmlh) . . 6 200 +255 12. the higher the limit for switching to firm (parallel realtionship) - Speed Normal Sport 10 6.6 114-168 8 5.6 6 4 65-113 7 4.3 169+ 199 10 6. above 34 krnlh. 8 0-33 34 .ACCELERATOR LIMITS (RELEASING) (Normal position) FIRM Accelerator Vehicle speed (krnlh) It should be noted that. the higher the speed. 64 . the vehicle has accelerated by4. in one second. Example: The vehicle is travelling at 36 kmlh.72 kmlh therefore 112 pulse in 500 ms. If. which corresponds t o 50 pulses per second and 25 pulses1500 ms.6 kmlh. 4. Reminder: + One pulse per second 0.3 X 2 = 8. the vehicle is ten travelling at: in other words.8 seconds.72 = 1.3 kmlh more than before. the computer would have had t o receive more than 28 pulses in the next 500 ms. Therefore one pulse in 500 ms 2 X 0. the speed sensor sends 28 pulses (3 additional pulses).after a switch to firm caused by the accelerator. the firm position is maintained for the whole time during which the limit is exceeded (3 pulses in 512 ms) with a minimum duration of 0. the acceleration or deceleration of the vehicle is greater than four pulses in 512 ms (= 1/2 per second).during the next 500 ms.Considering the vehicle acceleration if.44 krnlh. This is not sufficient to maintain the firm position. Therefore. * l l . I I Throttle I I I I I I I I j Fault I l 7 I I I I l I I Zk Acc I ! ZkDec t The suspension is not switched t o firm if the amount the pedal i s pressed down (throttle opened) is in the minimum pedal position zone minimum pedal position 15 steps so as to compensate for mechanical play. whilst this timer i s decrementing the vehicles eed becomes nonzero.3. Note: In the sport position. If. the suspensionwill switch t o the 'firm' state for a braking pressure greater then 35 bar. I I I I i I ~ o ~ t e p sjO I I I l I I I I I 1 I ! ! I I I I I I I I I I I 1 I . + Dynamic body anti-jump When a switch t o firm is tri gered by the accelerator being state if pressed down whilst the ve ~clespeed is zero. whlch can be reset. ?I P Braking If the vehicle speed is greater than 24 kmlh. - m + The limits for witching t o firm are multipled by 17 when pressing down or releasing the pedal from the moment when the rate of change of the pedal a in the 10%zone of the mechanical stroke (15 steps 10% from the pedal minimum position).5s timer.2s timer which maintians the irm state replaces the 3. The suspension will return t o the soft state when the pressure becomes less than 35 bar and after a one second timer.5s. a 1.Features Effective :*--------------stroke Fault : I Throttle SC II closed I . . I I I I I l I ! I I I I I I I I I ! :I 1 I l V ref-max Ref-diap : I l I I I I I I I I 1 $ tolerahce I V ref-min l I I l I I l I I J I I I I I I : 2 I3 245 I &5 I I I I I I I I I I I I II oc l I I I Open I l I lI I I I 100 steps 4 iIl . the f ~ r m maintained for a time of 3. the timer for teturning t o soft is multiplied by 1. The suspension will return t o the soft state when the amplitude o f the movement is less than a limit value and after a 0. Note: In the sport position.8s timer. BODY MOVEMENT LIMITS (ATTACK) (Normal position) FIRM Front suspension movement (mm) Vehicle speed (kmlh) .C- SWITCHING TO FIRM BY REACTION Body movement The vehicle speed must be greater than 10 kmlh and the movement (attach or release) must be greater than a limit as a function of the vehicle speed. The limits are different depending on whether the movement is in the 'attach'direction or the release' direction. the limits for switching t o firm as well as the timer remain unchanged. the lower the limit for switching to firm (inverse relationship) where this applies to both attack and release.80 120 160 200 240 Vehicle speed (kmlh) It can be seen that the higher the vehicle speed. .BODY MOVEMENT LIMITS (RELEASE) (Normal position) Front suspension movement (mm) 40 . 3 mls. It is updated every 500 ms as follows: HIaV.4 seconds. and if this occurs more than three times in three seconds. accelerator pedal speed and brake. If a steering wheel > 130* wheel impact and uneven road inhibited.. The 'uneven road' strategy is cancelled for the body movement sensor. steering wheel speed.' This is the average of averages. Uneven roads If the limits take the value of 60 mm for 0. the limits take the value of 60 mm for 0. The vehicle is travelling at 120 kmlh The limit for switching to firm on steering wheel angle is 260 +26 = 130 -2 Therefore.4 seconds.3 for the steering wheel angle. The 60 mm limit is measured with respect t o a second average height H . .= D- + A with 32 = average of the averages already calculated SELECTED 'SPORT MODE a The 'SPORT' position does not permanently impose the firm position. They are divided b 1.Features Wheel impacts If the movement speed is greater than 0.5 for the steering wheel angle. the uneven road function does not exist. Limits lowered by 33%. the limits takes the value of 60 mm for the next t w o seconds. The wheel impact and uneven road functions are not applied: If Example: - vehicle speed > 159 km/h the steering wheel angle is greater than half the 'firm' limit for the steering wheel angle at the considered speed. if a steering wheel < 13 *wheel impad and uneven road function applied (at 1200in attack. steering wheel speed( and accelerator pedal speed.. the limit of 48 mm changes t o 60 mm). It should be noted that in the 'SPORT' position. Timers extended by 30%: they are multiplied by 1. the suspension is in the "Firm" position (U electrovalve = 0). when the engine i s switched on.VEHICLE LEVELLING We have seen that when the supply to the computer is cut.. . If the pressure in the main spheres varies (passengers getting in or out. and causes the vehicle t o jump. the thirty second timer is also activated. Therefore the additional sphere is isolated. which suddenly alters the ride height of the vehrcle. the pressure difference translates as a influx (P additional > P main) or a reflux (P additional < P main) of fluid in the suspension cylinders. loading dr unloading) a pressure difference with respect to the additional sphere appears. the additional sphere remains isolated.V . Note: The anti jolt function is integratedinto the computer. When the ignition is switched on. as the additional sphere is connected to the circuit. which. Note : If the hydraulic pressure i s not sufficient. when . ROLE The aim of this system is to balance the pressures in the circuits by energising the computer when a door or the tailgate is opened for a period limited to ten minutes and timing the supply for thirty seconds when the doors or tailgate are closed. doors and tailgate closed. can cause a slight jolt.VEHICLE ANTI-JOLT A . the ignition is switched off. .C- SUMMARY OF OPERATION + Ignition 1 I Door contact Electrovalve control ?Qs I .OPERATING SAFETY When the ignition is switched on. all t h e testecf' elements are presumed t o be in their normal operating state -+ all fault counters are reset t o zero. the computer checks : The presence of the actuators : line continuity Its own circuits The lack of abnormal development in the counters. registers.- .-30s + Ignition Door contact l a t > l0 mins Eledrovaive control 10 mins VI. Everytime the computer is energised.. B - INITIALISING THE COMPUTER WHEN THE IGNITION IS SWITCHED ON When the ignition is switched on. the computer reinitialises t h e micro rocessors. etc.. then it : . Reinitialises the counters..RElNlTlALlSlNGAT A NON-ZERO SPEED The computer will be exceptionally reinitialised if an unforeseen disturbance occurs causing the vehicle t o switch t o the safety mode : Suspension in the "firm" state for as long as the straight line has not been validated over 200 metres if the speed of the vehicle is greater than 40 kmlh and the warning light is illuminated for three seconds. D - WATCHDOG The computer permanently checks that its internal programme is function~ngcorrectly. etc Illuminates the central warning light for three seconds or causes it t o flash for ten seconds a t a frequency of 1 Hz if a fault is memorised. registers. E . If this code does not exist or i s wrong. C - SELECTING THE DATA TABLES The computer has in i t s memory the tables of parameters for all the vehicles which can be fitted with hydractive suspension. the computer systematically chooses the table o f parameters of the XANTIA vehicle and switches the warning light on permanently.. the computer reads a code which tells it which table of parameters it should use. When initialised. . Where it is impossible t o control the electrovalves (computer broken. dY 2 - Body movement and vehicle speed sensors. electrovalves. brake pressure switch Only diagnostic through coherence is applied.AUTO-DIAGNOSTIC I- GENERAL The auto-diagnostic has been designed with the aim of improving reliability and preserving automat~coperating for as long as poss~ble. B . On the other hand. but automatic operation is maintained-Therefore. for sensor faults. accelerator sensors. computer There are two types of diagnostic : By coherence of the signals between themselves. 1 - Steering wheel. electrovalve connector disconnected. By electrical measurement. body movement and accelerator sensors.DOWNGRADED MODES 1 - Steering wheel. . 2 - Vehicle speed sensor Emergency speed strategy = 100 kmlh is used when the fault is validated. the suspension is in the "firm" state hydraulically. supply voltage too low). brake pressure switch The fault sensor is excluded from the system. the suspension is maintained in the "supple" position. comfort is maintained. allowing sensor and actuator suppl faults t o be detected quickly especially for isconnected connectors and connectors with microscopic breaks. D- CHECKING THE SYSTEM An after-sales test unit and the suspension computer can be connected in two different ways : m Slow rate with coded signals with the OUT 4097 Tor OUT 4120 T tools m Fast rate by serial link t o the ELlT 1 - By coded signals This type of test allows fault codes t o be read and erased..the vehicle must be stationary (0 kmlh) and the ignition must be on. . To carry out this_test. This therefore facilitates fault location. 4 . as well as the operting ...Erasing rnemor~sed faults The notion of a temporary fault allows a fault t o be displayed as soon as it has been detected by the computer and even before it has been confirmed.Electrovalves The two electrovalves switch to the "firm" position. 2 - By serial link This test can be carried out with the ignition on at any vehicle speed.Computer Attempts to reinitialise the computer result in the suspension switching to firm for a few seconds. Posssibilities available: Reading temporary and confirmed faults . warning lights.3 ... NORMALISPORT switch. m Dynamic analysis of the hydractive operation Controlling the actuators and warning lights -- Approximately every 100 ms. the computer transmits the status of i t s inputs and outputs: Status of the door switches. C- MEMORISING FAULT CODES Faults are stored in a non-volatile EEPROM memory (faults are not erased when the battery is disconnected). brake pressure switch. 8 For ease of uses. there is a specific hydractive computer for Diesel XM vehicles fitted with the DK5 ATE engine. pattery voltage . These two functions therefore aloow a complte functional test of the suspension system to be carried outwithout having to work on the vehicle wiring loom.arameters: steering wheel angle. This test can be static or dynamic. There is a single PSA reference in the factory and the table of paramters t o be used is chosen on the assembly line by loading a code remotely using a tester connected t o the computer via a serial link.. the tester can force the computer to operate an electrovalve and a warning light.. Loading t h e parameter table selection code remotely 8 01/93 + XANTIAvehicle hydractive computer fitted to XM vehicles. only one computer is used which has two tablezof parameters in its memoryfor the XANTIA and XM. diagnostic parameters.. . 8 If an error occurs (code not transmitted or wrong value). The only difference between the two applications is the setting parameters (laws for switch~ngt o firm. constructive parameters). the computer chooses table No1 (XANTIA) by defaults. the computer parameters and i t s serial numbers. vehicle speed. With the behicle stopped. Note: At present. 8 Computer identification This gives the hardware and software versions. COUNTER FAULT firm U battery within range 11.5Vfor2s 9 suspension firm relaunch attempt every 30 S 2 Suspension firm relaunch attempt every 30 S ELE TESTBY VALIDATION DETECTION STRATEGY C. SIGNAL TES COHERENCE T - U b c 11Vfor2s u b > 16.5V-16V _+ 0.5Vfor 2 s Electrovalve control incoherance < 10 ms during full voltage control of 500 rns Electrovalve control incoherence for 500 ms X X X 60 1 . WITH CODED SIGNALS 53 ANOMALY DETECTED battery voltage outside range microscopic supply breakage ELECTROVALVE (Front EV) 31 (Rear EV) 32 EMERGENCY STRATEGY EMERGENCY STRATEGY ANNULLED OR VALID.FUNCTION TESTED SUPPLY + battery or earth FAULT CODE DIAG. n o t at fault speed > 30 kmlh n o brake info 3 decels o f 0.4" for 3 km if V > 100 kmlh.4"for 1 k m or having had a st.4" then straight line acquistion switch closed for 10s(F=0) automatic : switch open suspension and decel. n o detection 21 open circuit short circuit F = laccel>l5% f o r 10 S speed > 30 kmlh accel.S S ELEC. X 3 X 5 X 5 automatic suspension EMERGENCY STRATEGY ANNULLED OR VALID.5s .4Oonce: st. W? eel l angle 5 6. TEST TESTBY VALIDATION EMERGENCY SIGNAL STRATEGY COHERENCE X 4 .FUNCTION TESTED STEERING WHEEL PRESSURE SWITCH FA ULT CODE DIAG. WITH CODED SIGNALS 23 ANOMALY DETECTED Open circuit n o t working short circuited DETECTION STRATEGY I measured > I ref max I measured < I ref min for 2 s if Veh Sp < 100 kmlh after ignition. of 0. wheel angle measured > 6. COUNTER FAULT I ref min < I measured I measured < I ref max then straight line acauistion st.469 in 1.1 g i n 1. wheel angle S 6. st. wheel an le > 6. . km'h V< 5 kmlh for 28 s following drop and accel >l5% X 1 speed>30 krnlh and no transition in the 5 s followin the brake switc?lsignal X 5 V signal >V ref max V signal< V ref rnin for 2 s BODY MOVEMENT 25 open circuit broken short circuited ACCELERATOR 22 open circuit __-__----_-_---..------ TESTBY ELEC.------------.----------. COUNTER FA ULT X 5 10 V = 100 km/h signal return coherent for 20s automatic suspension movement angle measured > 2 steps automatic suspension signal return within range for 20 s -. VALIDATION EMERGENCY TEST COHERENCE STRATEGY ANOMALY DETECTED 24 EMERGENCY STRATEGY ANNULLED OR VALID.---------------- Short circuit + signal return w~thinrange for 20 sand speed = MPH .-------.FUNCTION TESTED VEHICLE SPEED FAULT CODE DIAG. WITH CODED SIGNALS DETECTION STRATEGY link in open circuit or short circuit accel > 15% and no spped signal for 30 s X sensor broken inspeed 512 rns (V > Off0 0 krnlh). VALIDATION EMERGENCY TEST SIGNAL BY TEST COHERENCE STRATEGY X 10 X 1 I EEprom "Check sum" test + EEPROM erasure + readJwrite test sendinglreceiving test d ~ a gl. ~ n e when computer enerqised tlectrOvalve tatu us" 1 "Inputwtest control stage for 2 S short circuited Electrovalves n o t or open circuit controlled EEPROM memoryfault COMPUTER 54 X X 1 1 EMERGENCY STRATEGY ANNULLED OR VALID. WITH CODED SIGNALS ANOMALY DETECTED DETECTION STRATEGY prog or # p fault internal watchdog ELEC. if V>40 kmlh function normal where ~ossible fault codes emitted by warning light firm suspension "Status" "Input" for 2 s o n the 2 stages . firm susp. COUNTER FAULT reset i p .FUNCTION TESTED FAULT CODE DIAG. II - COMPUTER CONNECTIONS WHITE CONNECTOR 12567810 11 12 13 14 15 - Positive supply of front electrovalve Positive supply of rear electrovalve Diagnostic line Tailgate switch earth signal ~ o oswitches r earth signal Earth Control through earth of test light Vehicle speed information Normal rule (earth)/sport rule("openV)signal Steering wheel sensor Positive supply of illumination of switch light in sport" position Earth BLACK CONNECTOR 12345910 11 12 13 14 15 - + direct + direct + Accelerator pedal sense! 5 V supply Accelerator pedal position information (cursor output) Computer after ignition supply Steering wheel sensor 2 information Steering wheel sensor 5 V supply Braking sensor signal Accelerator pedal sensor Body movement sensor signal Body movement sensor signal Steering wheel sensor 1 information + + Ill- DASHBOARD LIGHT OPERATION It is supplied directly on the + after ignition side (12 V) and is 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 a frequency of 1 Hz when driving or when the ignition is switched on after a shorter initialisation than previously (= 1 S). m If the microprocessor i s faulty +light permanently on -, FUNCTION TESTED SUPPLY + battery or earth ELECTROVALVE FAULT CODE DIAG. WITH CODED SIGNALS 53 ANOMALY DETECTED Ub< l l V f o r 2 s batter voltage outsi e range Ub>16.5VforZs microscopic supply breakage Electrovalve control incoherance < 10 ms during full voltage control of 500 ms J (Front EV) 31 (Rear EV) 32 DETECTION STRATEGY Electrovaive control incoherence for 500 ms ELEC. SIGNAL TEST COHERENCE X X. X ! ! VALIDATION 'EMERGENCY STRATEGY EMERGENCY STRATEGY ANNULLED OR VALID. COUNTER FAULT U battery 60 1 suspension firm 9 suspension firm relaunch attempt every 30 S 2 Suspension firm relaunch attempt every 30 S within range 11.5V-16V f 0.5VforZs 469 in 1. open circuit EMERGENCY STRATEGY ANNULLED OR VALID. WITH CODED SIGNALS 23 ANOMALY DETECTED Open circuit not working short circuited DETECTION STRATEGY I measured > I ref max I measured <.4" once: st. TEST SIGNAL BY STRATEGY TEST COHERENCE X 4 automatic suspension X 3 PRESSURE SWITCH 21 short circuit F = 1accel>15% for 10 S speed > 30 kmlh accel.5 S .4" then straight line acquistion 7.4" for3 l? mif V > 100 kmlh.FUNCTION TESTED STEERING WHEEL FA ULT CODE DIAG.4"for 1 km or having had a st. wheel angle measured > 6.I ref min for 2 s if Veh Sp < 100 kmlh after ignition. COUNTER FAULT switch closed for 10s (F = 0) automatic suspension switch open and decel. not at fault speed > 30 kmlh no brake info 3 decels of 0. st.5 S X S X 5 I ref min < I measuredI measured < I ref max then straight line acquistion st. o f 0.1 g in 1. no detection VALIDATION EMERGENCY ELEC. wheel angle S 6. wheel an le > 6. W eel an le g 6. FUNCTION TESTED FAULT CODE DIAG. within range signal return for 20 s . TEST s BY ~ G ~ ~ STRATEGY ~ TEST COHERENCE COUNTER FAULT YIALID accel > 15% and n o spped signal f o r 30 s speed drop o f 30 krn/h in 512 rns (V > 30 krnlh). V e 5 km/h f o r 28 s sensor broken following drop and accel >l5% link in open circuit or short circuit VEHICLE SPEED 24 BODY MOVEMENT 25 ACCELERATOR 22 open circuit broken short circuited speed>30 kmfh and n o transition i n t h e 5 S followin the brake switc signal open circuit broken short circuited Vsignal >V ref max V signal< V ref rnin for2s X 5 X 1 X 5 V = 100 kmlh signal return coherent for 20 5 Ff 10 X automatic suspension movement angle measured >2 steps automatic suspension . WITH CODED SIGNALS ANOMALY DETECTED DETECTION STRATEGY EMERGENCY STRATEGY VALIDATION EMERGENCY AN ULLED OR ELEC. WITH CODED SIGNALS 54 ANOMALY DETECTED DETECTION STRATEGY progor m p fault internal watchdog EEPROM memory fault EEprom "Check sum" test + EEPROM erasure + r e a d h r i t e test sendingheceiving test when computer energised 1 @'Inputw test @'Statusm for 2 S Electrovalves n o t controlled d ~ a g l.i FUNCTION TESTED COMPUTER FAULT CODE DIAG. firm susp. COUNTER FA ULT reset 1p. if V>40 kmlh function normal where possible fault codes emitted by warning liqht firm suspension "Status" "Input" for 2 S o n the 2 stages . VALIDATION EMERGENCY SIGNAL TEST COHERENCE STRATEGY X X 10 X 1 1 X 1 EMERGENCY STRATEGY ANNULLED OR VALID. ~ n e t'ectrOva've control stage circuited or open circuit TESTBY ELEC.
Report "Hydractive Citroen Official Training Manual"