Tài Liệu Hộp Số Audi R8 Power Transmission

613 Audi Vorsprung durch Technik Self Study Programme 613 For internal use only Audi R8 Power Transmission All rights reserved Technical specifications are subject to change Copyright AUDI AG I/VK-35 service.training@audi.de AUDI AG D-85045 Ingolstadt Technical status 03/12 Printed in Germany A12.5S00.97.20 Audi Service Training The Audi R8 sees Audi offering, for the first time, a high-performance sports car based on a mid-engine concept The engine positioning fore of the rear axle helps to ensure a balanced weight distribution and a low centre of gravity This basic configuration allows a high level of driving stability and good transverse acceleration Driving dynamics are further enhanced by the combination of a bespoke mid-engine concept and quattro all-wheel drive, with a strong emphasis being placed on sportiness and driving enjoyment Due to the mid-engine concept and the demands on driving dynamics, the quattro full-time all-wheel drive system in the Audi R8 has been implemented in a different way to previous Audi quattro drive systems In the case of the mid-engine concept with quattro all-wheel drive in the Audi R8, drive is transmitted dynamically to the front axle by means of a viscous coupling Furthermore, a limited slip differential in the rear axle drive improves rear axle traction under high transverse acceleration 613_006 When buying the Audi R8, the customer can elect to change gear manually using the 6-speed manual gearbox with double-plate dry clutch or to drive away and change gear fully automatically using the optional R tronic gearbox An innovative selector mechanism allows the driver to make the choice of driving in Automatic mode or changing gears manually In addition, the driver can select Sport mode Want to find out more about the technology behind this power transmission system? If so, read on and learn all you need to know about power transmission in the Audi R8 613_007 This self study programme teaches a basic knowledge of the design and functions of new models, new automotive components or new technologies It is not a repair manual Figures are given for explanatory purposes only and refer to the data valid at the time of preparation of the SSP Always refer to the current technical literature when carrying out maintenance and repair work ! Note Reference Contents Introduction Mid-engine concept with quattro all-wheel drive Selector mechanism Selector mechanism – manual gearbox _ Clutch pedal switch F36 Reversing lights switch F4 _ Selector mechanism – R tronic 10 Special aspects of operating R tronic 12 Operating noise of R tronic 13 Front axle drive 0AZ Specifications _ 15 Viscous coupling _ 16 Lube oil supply _ 18 Operating instructions _ 19 Manual and automatic gearboxes Sectional view of basic gearbox _ 20 Specifications _ 22 6-speed manual gearbox 086 _ 23 Automated 6-speed manual gearbox 086 – R tronic _ 24 Gear set – internal shift mechanism – synchromesh _ 26 Rear axle drivewith limited slip differential _ 28 Lube oil supply _ 30 Gear oil cooling _ 32 Clutch Double plate clutch 34 Clutch control – manual gearbox _ 35 R tronic – hydraulic control unit System overview _ 36 Hydraulic diagram 38 Selector mechanism – R tronic 40 Clutch control – clutch adaptation – measured values _ 42 Electro-hydraulic shift mechanism _ 46 S-CAM _ 48 Shift sequence – gear-changing 50 Basic setting – shift adaptation – self-diagnostics – measured data 54 Putting gearbox into neutral after certain system malfunctions _ 56 Electronic control unit Automatic gearbox control unit J217 58 Basic settings – adaptations 59 Encode control unit 59 Functions – displays/warnings 60 Functions – ignition key removal lock 61 Functions – starter control unit _ 61 Function diagram 62 CAN information exchange 64 Sensors 66 Actuators 70 Service Tow-starting/towing _ 73 Annex Index 74 Test your knowledge (Part 1) _ 45 Test your knowledge (Part 2) _ 65 Introduction Mid-engine concept with quattro all-wheel drive The outstanding performance is the quattro® all-wheel drive system is based on a weight distribution of 44 : 56 in favour of the rear axle If needed, up to 420 Nm of drive can be transmitted dynamically to the front wheels by a viscous coupling Manual selector mechanism with 6-speed manual gearbox or automatic selector mechanism with shift by wire technology in the R tronic, see page 10 R tronic shift actuator, see page 36 or the shift unit in the manual gearbox, see page 6 Limited slip differential, see page 28 Drive shaft 6-speed manual gearbox 086 or optional automated 6-speed manual gearbox 086 (R tronic) R tronic hydraulic unit The manual gearbox 086 and the R tronic use a near-identical basic gearbox This is a full synchromesh 6-speed manual gearbox A high synchronisation capacity and short throws allow slick gear-shifting A double plate clutch transmits the engine power to the gearbox The R tronic has an electro-hydraulic shift unit which provides for drive-away and performs gear changes fully automatically This type of gearbox is therefore referred to as an automated manual gearbox Several aspects of the basic gearbox have been modified for this purpose The transmission ratios are identical to those of the manual gearbox, but in both cases they are adapted depending on engine type Front axle drive of 0AZ with viscous coupling, see page 14 613_008 Schematic diagram of power flow Front axle differential Drive concept The quattro concept in the Audi R8 is a slip-controlled all-wheel drive system The rear axle is the main drive axle Engine torque is transferred through a spur gear to the rear axle differential, where a limited slip differential ensures a continuous flow of drive torque even under high transverse acceleration Engine torque is transmitted to the viscous coupling through a second spur gear in the front axle drive, i.e without the centre differential Depending on the speed differential between the front and rear axles, the viscous coupling transfers a defined amount of torque to the front axle drive Here, an open differential distributes the torque equally to the front and rear The EDL control unit is specially adapted to the R8 drive concept and assists torque distribution in the usual way Rear axle differential with limited slip differential Front axle drive Viscous coupling – transmits a defined amount of torque to the front axle Drive shaft – transfers the drive torque to the front axle gearbox It is located inside the engine (it runs through the engine oil pan), which means it is not visible from the exterior Front axle drive spur gear Rear axle drive spur gear Manual gearbox gear set 613_009 Selector mechanism Selector mechanism – manual gearbox Direction of travel Selector cable for gear selection The Audi R8 with manual gearbox is equipped with a gate shift system which allows short and slick gear changes and provides exact feedback on the gear engaged The high-quality matt finish aluminium used underscores the sporty character of the Audi R8 To start the engine on models with a manual gearbox, the clutch must be fully depressed This information is provided by the clutch pedal switch F36 on the clutch slave cylinder as a precaution against unintentional drive-away at start Selector cable for shift gate selection Shift movements are transmitted from the selector mechanism to the gearbox via two selector cables (Bowden cables) The robust housing and lever parts as well as the high-quality bearings and joints in the selector mechanism and on the gearbox shift unit provide for very direct transfer of shift commands to the gearbox In addition to the high-quality finish, a very direct and sporty shift feel is conveyed The selector cables are set using the quick-release fasteners on the gearbox Reversing lights switch F4 Overview of the external and internal shift mechanisms Ball joints in the joint forks provide for direct transfer of shift movements Shift locks on the selector shaft (and selector lever) 613_010 Direction of travel Selector cable for shift gate selection Selector cable for gear selection 613_011 Clutch pedal switch F36 To start the engine on models with a manual gearbox, the clutch must be fully depressed This is indicated by the clutch pedal switch F361) on the clutch slave cylinder This measure safeguards against unintentional drive-away at start 1) The clutch pedal switch is also referred to in some service documents as clutch position sender G476 This can lead to irritation and confusion with the clutch position sender first mentioned on page 40 Clutch pedal switch F36 – mounted on the clutch slave cylinder Circuit diagram – clutch pedal switch F36 Movement of the piston with ring magnet on actuation of the clutch pedal Ring magnet – is located on the piston of the clutch slave cylinder Reed contact 1 (NC contact) – CCS signal Position of ring magnet when clutch pedal is in home position Signal for deactivation of cruise control Shift point Reed contact Signal for start enable (interlock) Shift point Reed contact 613_012 Maximum clutch pedal travel 613_013 Reed contact 2 (NC contact) – start enable signal Possible collision point when shifting from 2nd to 3rd gear Notes on operation The gate shift selector offers sporty gear-shifting and a sporty look When changing gate, e.g to shift from 2nd to 3rd gear (or vice versa), the shift lever and the finger of the aluminium gate can come into contact with one another during the gearshift This produces an audible clicking sound because it is not possible to use a damper element for noise reduction It is therefore important to ensure, firstly, that the selector mechanism is set correctly and, secondly, to ensure that gearshifts are performed exactly Launch Control Program A Launch Control Program is available for the R8 with V10 engine and manual gearbox The Launch Control Program provides maximum power delivery from a standing start Refer to the user manual for details of requirements, operating instructions and other information R Normal position of selector lever – in centre of shift gate 3/4 613_014 Reversing lights switch F4 The reversing lights switch F4 is supplied with term 15 via a fuse As soon as the selector lever is moved into the reverse gate, switch F4 connects term 15 directly to the onboard power supply control unit J519 The onboard power supply control unit J519 actuates the reversing lights and relays the signal for the automatic anti-glare rear-view mirror Y7 to the gateway J533 by convenience CAN bus The gateway, in turn, supplies the corresponding control units via their respective bus systems The information supplied by the reversing lights switch F4 is required for the following functions: • Activation of the reversing lights • Automatic anti-glare rear-view mirror/door mirror • Activation of the front passenger door mirror fold-away function • Activation of the parking aid or reversing camera • Audi hold assist (ESP) Shift detent of the manual gearbox Manual gearbox shift unit – engaged in R position Shift detents of the selector shaft and selector lever – shown here engaged in R position Reversing lights switch F4 Selector shaft Detent for each of the gears and for the home position of the shift finger (and the selector lever) in the centre of shift gate 3/4 The ball socket in the selector shaft is on one side only This axial detent is effective only outside the neutral position 613_015 The illustration shows the shift detent in the neutral/home position of shift gate 3/4 Selector mechanism – R tronic In the R tronic there is no mechanical connection between the selector mechanism and the gearbox Selector lever positions and shift commands are registered, evaluated by the gear lever sensors control unit J587 and sent to the gearbox control unit J217 by CAN data bus The gearbox control unit controls the electro-hydraulic control unit on the gearbox based on this information This control mode is referred to as "shift by wire" The R tronic selector mechanism differs not only visually from the selector mechanisms of the other automatic gearboxes The shift diagram has been specially adapted to suit the functional principle of the automated manual gearbox The selector lever has two lockable normal positions (left and right positions) from which the corresponding functions can be selected (see Fig. 613_018) Selector lever position display Y5 Sport program button E541 – is read in by selector lever sensors control unit J587 The information "Sport mode" is relayed from J587 to the gearbox control unit J217 and to the engine control unit by CAN data exchange Refer to page 64 for further information Refer to function chart on page 62 Hall sensors Selector lever sensors control unit J587 The selector lever sensors control unit J587 determines the selector lever positions for the gearbox control unit, … controls the LEDs in the selector cover and in the selector lever position display Y5, … transmits all information to the automatic gearbox control unit J217 by powertrain CAN bus, … is the interface to the sport program button E541 613_017 O-ring for noise reduction 10 Permanent magnet Bottom end of selector lever The selector lever positions are monitored by multiple Hall sensors At the bottom end of the selector lever there is a permanent magnet which controls the corresponding sensors according to the selector lever position The selector lever sensors of the J587 evaluate the signals and transmit the selector lever positions to the gearbox control unit J217 J217 utilises this information to identify the driver's input and controls the valves of the hydraulic control unit to engage the corresponding gears and clutch functions 613_016 Function diagram Key: E541 F G182 G270 G476 G604 G616 J217 J510 J587 N255 N284 N285 N286 S V387 Y5 Colour code: Sport program button Brake light switch Gearbox input speed sender Gearbox hydraulic pressure sender Clutch position sensor Gear recognition sensor Gear recognition sensor Automatic gearbox control unit Gearbox hydraulic pump relay Selector lever sensors control unit Clutch actuator valve Gear selection valve Gear selection valve Gear selection valve Fuse Gearbox hydraulic pump Selector lever position display Shielded line The connectors for valves N255 to N286 are identical in design but not coded To ensure that the connectors can be connected correctly, the wiring harness connecting to the electromagnetic valves is colour-coded The valves are not usually colour-coded This is why there is danger of mixing up the electrical connectors To ensure that the connectors are reconnected to the matching valves, they must be unmistakably marked before disconnecting 1) 2) 62 4.2l V8 engine 5.2l V10 engine Data bus interface: CAN-L Powertrain CAN low CAN-H Powertrain CAN high Plug connections on the automatic gearbox control unit J217: A 52 pin connector, pins 1 – 52 B 28 pin connector, pins 53 – 80 613_002 Auxiliary signals – separate signal lines 3) Pin 42 – signal – start enable If the conditions for engine starting have been met, the gearbox control unit sends the start enable signal to the engine control unit The voltage level at pin 42 changes from approx 10 to 0 volts Refer to "Starter control" on page 61 Pin 48 – signal – engine speed (TD signal) from engine control unit, see page 69 Pin 72 – a line is assigned to this connection, but the connection is not functional Pin 78 – signal – driver door open When opening the driver's door, the onboard power supply control unit J519 activates relay J789 for a defined period of time J789 in turn switches terminal 30 to the pin 78 input The hydraulic pump V387 is then activated briefly in order to build up a certain pressure inside the hydraulic system To ensure that the hydraulic pump does not start every time the driver's door is opened, it is activated only once within 30 minutes Pin 49 – signal – vehicle diagnostics (K line) Pin 76 – signal – start request3) Information on a start request (ignition key position – engine start) from the steering column electronics control unit J527 Pin 76 is switched from ground to 12 volts The signal is simultaneously sent to the engine control unit Refer to "Starter control" on page 61 The start request signal is also referred to as "status term 50" or "term 50 ON" in other documents 63 CAN information exchange J217 automatic gearbox control unit J587 selector lever sensors control unit (1) − − − − − − − − − − − − − − − − − − − Selector lever position − Sport switch status − Fault status Selector active (2, 3, 4) Nominal engine speed (3) Gearbox protection (3) A/C compressor OFF (3) Clutch status (3) Gear selected Gang (3, 4) Target gear (3, 4) Drive program (2, 3, 4) Drag coefficient (3) Gearbox limp-home mode (3) OBD status (3) Clutch torque (nominal/actual) (3) Throttle-blipping (3) Nominal idle speed (3) Synchronisation speed (3) Clutch temperature warning (2) Gear indicator – actual gear (2) Activation of various instrument cluster displays (2) J623 engine control unit + J624 engine control unit (3) − − − − − − − − − − − Engine speed Accelerator angle Engine torque data (nominal/actual) Kickdown Driver input torque Coolant temperature Brake light switch, brake pedal switch Cruise control system status CAN status Altitude information Various system states (e.g warm up/driving cycle) − Engine oil temperature J104 ESP control unit (4) − − − − − ESP intervention System status Lateral acceleration Wheel speeds (FL, FR, RL, RR) Speed Powertrain CAN bus J533 data bus diagnostic interface (2) − − − − Date, time Mileage Ambient temperature tiptronic + / – Information sent by control unit J217 The number in brackets indicates the bus user to which the information is sent − NO contact status − Start request − Handbrake status Information received and evaluated by control unit J217 In the CAN information exchange process shown here, only the main items of information are given In reality, a great deal more information is exchanged This can vary from version to version 64 Test your knowledge (Part 2) Which of the following statements regarding electro-hydraulic shift mechanism are correct? □ □ □ a) The electro-hydraulic shift mechanism uses different shift kinematics to manual gearbox 086 b) In the case of the R tronic, gear-shifting is performed by the gear actuator c) In comparison with the manual gearbox, only two shift rods/shift forks are required Which of the following components of the R tronic are connected to the selector shaft? □ □ □ □ a) The shutter plate for the gear recognition sensors b) The shift finger with locking gate for rotational locking c) The hydraulic working piston (hydraulic cylinder) d) The gate block (pin) Which of the following statements on the so-called "S-CAM" are correct? □ □ □ □ a) The S-CAM is used solely for shifting into neutral b) The S-CAM is a component of the shift actuator c) The S-CAM helps to create the rotational movement of the selector shaft required to switch between shift gates d) The S-CAM brake is activated when the engine is started How can the gearbox be put into neutral in the event of certain faults in the hydraulic control unit? □ □ □ a) The gearbox can easily be put into neutral using the emergency release mechanism b) The gearbox can be put into neutral using the tool kit A description of the procedure can be found in the operating instructions c) The selector shaft can be put into neutral manually This work must be performed by trained specialist personnel and requires a detailed knowledge of the various steps involved In which position in the vehicle is the automatic gearbox control unit J217 fitted? □ □ □ a) Behind the right-hand seat, under a cover b) Behind the left-hand seat, under a cover c) In the engine bay, under a cover Which adaptation values are determined by the diagnostic tester during the basic setting procedure for the gear actuator? □ □ □ a) The zero calibration value of the clutch actuator valve N255 b) The position of the closed clutch c) The limit positions of the gear actuator in each of the gears Which of the following statements on the gear recognition sensors are correct? a) The sensors utilise an all-mechanical contact transmitter b) The sensors are aided by a Hall sensor c) The sensors function as all-inductive sensors d) These sensors are so-called PLCD sensors Test solutions: b; a, b, c, d; b, c; c; a; a, b, c; b □ □ □ □ 65 Sensors Gear recognition sensor G604, gear recognition sensor G616 To enable the desired gears to be selected, the gearbox control unit must know the exact position and movement of the shift finger The exact position of the shift finger can be derived from the angular and axial positions of the selector shaft G604 determines the axial movements and positions of the selector shaft G616 determines the rotational movement and angular positions of the selector shaft for recognition of the current shift gate The gear currently engaged can be detected from the signals generated by G604 and G616 Sensors G604 and G616 are identical and record a rotational movement A kinematic mechanism with levers and shutter plates indicates the movements of the selector shaft to the sensors Gear recognition sensor G616 Shutter plate/lever The sensors are aided by a Hall sensor A voltage signal dependent on rotational angle is generated as a sensor signal Sensors G604 and G616 as well as the respective limit positions of the gears must be adapted to the gearbox control unit Refer to pages 54 and 59 for more information Effects of signal failure Depending on the driving situation and fault type, different limp-home programs are started The gearbox cannot change gears without the signals from senders G604 and G616 (particularly if G604 fails) If possible, vehicle operation is maintained by holding the gear currently engaged or if, say, the vehicle is stationary, by shifting into neutral or opening the clutch Gear recognition sensor G604 Shutter plate/lever 613_095 ! 66 Note Older sensors have tin-plated pins, while more recent sensors have gold-plated pins The advantage of gold-plated connectors is that they are more resistant to corrosion As a result, the connector retains a constant contact resistance for a long period of time The low signal currents are thus transmitted reliably However, this only applies if the contact pairing (pins and connector) are made of the same material This means that a gold-plated pin must not be mated with a tin-plated connector as this will promote corrosion (contact corrosion) If new sensors are fitted in a vehicle equipped with old-type sensors (e.g due to replacment of the gearbox, the shift actuator or the sensors), the wiring harness connecting to the sensors must be converted to gold contacts For this purpose, there is a prefabricated wiring harness which must be fitted using the wiring harness repair kit VAS 1978B (refer to ETKA and workshop manual) Clutch position sensor G476 To control the clutch during drive-away and shift gears, the gearbox control unit requires exact and reliable feedback on the actuation status of the clutch (current clutch torque, clutch open or closed) This information is generated by determining the travel of the clutch release mechanism The task of G476 is to measure the travel of the clutch release mechanism It is a so-called PLCD sensor The abbreviation PLCD stands for: Fitting bracket for G476 Permanent magnetic Linear Contactless Displacement sensor This is a contactless sensor which measures linear displacement with the aid of a permanent magnet For more information on the functional principle of this sensor, refer to SSP 241, page 56 ff 613_096 Clutch position sensor G476 Permanent magnet – moves in conjunction with the release bearing in an axial direction Clutch slave cylinder with release bearing and permanent magnet for the clutch position sender The information provided by G476 is evaluated for the following functions: • Recognition of clutch operating states (open, closed, current clutch torque) for controlling the electro-hydraulic clutch control • Feedback for shifting gears and for engine start enabling (the clutch must be open during the gearshift and when starting the engine) • Determination and adaptation of the clutch kisspoint for calculating the clutch torque • Determination and adaptation of clutch status (clutch index) • Determination of clutch temperature (calculation model) Release bearing To ensure a good level of drive-away and shift comfort, the basic setting procedure must be carried out on the clutch using the diagnostic tester Refer to pages 42 and 59 for more information Effects of signal failure Depending on the driving situation in which the fault occurred at G476, vehicle operation is, where possible, maintained by holding the gear currently engaged When engine idling speed is achieved, the clutch is opened and neutral is selected Since the "clutch open" state is not detected if G476 fails, the start enable signal is not sent to the engine control unit, with the result that the engine cannot be started Fault indication in instrument cluster with warning level 2, see page 60 67 Gearbox hydraulic pressure sender G270 G270 is an electronic pressure sender It supplies a pressuredependent voltage signal and is used for determining the system pressure The gearbox control unit utilises G270 to control the cut-in and shut-off pressures of the hydraulic pump Therefore, the system pressure is set to between 40 and 50 bar The signal generated by G270 is also used for calculating the shift forces Gearbox hydraulic pressure sender G270 Effects of signal failure In the event of failure of the sensor, the hydraulic pump is activated in a time-dependent manner The system pressure is considerably higher, as it is defined by the pressure limiting valve (see pages 38 and 71) As a result, gearshifts can appear to be louder Measurement range: Signal voltage: 613_097 Gearbox input speed sender G182 G182 is an inductive sender and records the speed of the gearbox drive shaft (after the clutch) The signal is also output as the clutch speed or clutch output speed The reverse gear sprocket serves as a sender wheel – 80 bar 0 bar = 0.5 volts 80 bar = 4.5 volts Gearbox input speed sender G182 Reverse gear drive sprocket The signal generated by G182 … is used in conjunction with the engine speed (TD signal) to calculate the clutch slip for controlling the clutch … is used for determining the synchronous speed for gearshifts … is required for clutch adaptation Effects of signal failure The gearbox is automatically put into neutral when the vehicle is at a standstill A limp-home program maintains limited vehicle operation in manual mode up to 3rd gear A corresponding fault is indicated in the driver information system 613_098 ! 68 Note G182 is also fitted in the manual gearbox but is not functional here It serves only to seal the aperture in the end cover Engine speed signal (TD signal) The TD1) signal is a square-wave signal which is processed by the engine control unit and is synchronous in frequency to the engine speed The pulse width ratio is approx. 50% and a defined number of square-wave pulse are output per revolution of the engine The TD signal serves as redundant information and is used to plausibilise the engine speed information received from the powertrain CAN and as a substitute signal for the CAN information, see function diagram on page 62 The engine speed is key information for the gearbox control unit It represents the clutch input speed The engine speed … is used in conjunction with the signal from G182 for exact control of the clutch (determination of clutch slip) … is used for controlling the selector mechanism and for the determination of synchronous speeds … is required to make various adaptations Effects of signal failure No effect as long as the engine speed is provided by CAN data bus 1) TD stands for "Time Division" in the context of the engine speed signal and refers to the type of signal Refer to SSP 198, page 60 69 Actuators Electromagnetic valves Clutch actuator valve N2551) Electromagnetic valves convert the hydraulic control current to a hydraulic control current, which in turn is used to actuate the control elements Valve N255 is a so-called proportional flow control valve It sets a hydraulic volumetric flow proportional to the control current N255 serves to actuate the clutch by means of a clutch slave cylinder Refer to hydraulic diagram on page 38 When fitting the valve, attention must be paid to the installation position and care taken to ensure that the ring seals are correctly assigned and fitted Refer to Workshop Manual Effect of failure • Gearbox limp-home mode – warning level • Drive-away and gear-shifting are not possible while driving, the gearbox is put into neutral when the vehicle is stationary – the engine can be started 613_099 Flow rate in l/min Zero flow 0.5 mA Key: A T P 613_101 Control current greater than 500 mA (e.g 600 mA) 613_102 Control current less than 500 mA (e.g 400 mA) 1 mA 613_105 613_100 Control current approx. 500 mA A – P characteristic A – T characteristic Output – control line or connection to clutch slave cylinder, see page 41 Tank – return line to oil tank (reservoir) Pressure connection – from system pressure (pressure accumulator) – N255 is operated starting from the centre position The valve is in its centre position at a control current of approx 500 mA Connection A is closed This position is referred to as the zero-flow position, see Fig. 613_105 – If the control current is increased, connection A is opened towards connection P A pressure is built up in the clutch slave cylinder See characteristic curve A – P in Fig. 613_105 – If the control current is decreased, connection A is opened towards connection T The pressure in the clutch slave cylinder is reduced, see characteristic curve A – T in Fig. 613_105 Zero flow adaption 613_103 Control current 0 mA 613_104 Control current greater than 1000 mA 70 The exact current value for zero flow is very important for the gearbox control unit, because it is the basis for determining the drive current As the valves are subject to a certain manufacturing tolerance, the value for zero flow must be adapted This adaptation is made for the "gear actuator basic setting" function or during operation if the vehicle is stationary for a defined period of time with the engine idling and the gearbox in neutral or 1st gear Gear selection valve N284 Valve N284 is an electrically actuated solenoid valve It controls the hydraulic pressure and has two switching positions (open/close and on/off ) N284 controls the S-CAM brake and is used in conjunction with N285 and N286 to switch between shift gates Refer to hydraulic diagram on page 38 When fitting the valve, care must be taken to ensure that the ring seals are correctly assigned and fitted Refer to workshop manual Special feature of N284: A pressure limiting valve is integrated in N284 It opens at approx 80 – 90 bar and protects the hydraulic system against excess pressure 613_106 Effect of failure • Gearbox limp-home mode – warning level • The gearbox is put into neutral when the vehicle is stationary – the engine can be started Gear selection valve N2851) Gear selection valve N2861) Valves N285 and N286 are so-called proportional pressure control valves They set a hydraulic control pressure which is proportional to the control current Both valves are identical N285 is used for shifting the odd-numbered gears N286 is used for shifting the even-numbered gears and reverse gear Refer to hydraulic diagram on page 38 When fitting the valve, care must be taken to ensure that the ring seals are correctly assigned and fitted Refer to workshop manual Effects of failure of N286 • Gearbox limp-home mode – warning level • It is not longer possible to shift towards the even-numbered gears If 1st, 3rd or 5th gear is selected, the gearbox cannot be put into neutral – the engine cannot be started • If an even-numbered gear or reverse gear is selected, the gearbox can be put into neutral with the aid of N285 – the engine can be started 613_107 Effects of failure of N285 • Gearbox limp-home mode – warning level • It is no longer possible to shift towards the odd-numbered gears If 2nd, 4th or 6th gear is selected, the gearbox cannot be put into neutral – the engine cannot be started • If an odd-numbered gear is selected, the gearbox can be put into neutral with the aid of N286 – the engine can be started 1) The connectors for the electromagnetic valves are identical in design (they are not coded) To ensure that the connectors can be connected correctly, the wiring harness connecting to the electromagnetic valves is colour-coded The valves are not usually colour-coded, which is why the electrical connectors are easily confused To ensure that the connectors are reconnected to the matching valves, they must be unmistakably marked before disconnecting 71 V387 Hydraulic pump motor – hydraulic pump The hydraulic pump motor V387 is a brushless DC motor It is activated by the gearbox control unit via a relay and drives a compact high-performance gear pump Refer to the function diagram on page 62 and the description on page 39 V387 and the hydraulic pump are mounted independently of one another on a bracket The engine shaft is connected to the pump shaft by a coupling piece A moulded foam part (sponge) is located below the engine V387 The sponge protects the electric motor if the hydraulic pump becomes leaky at the shaft seal The electrical connection has only one pin for the relay power supply The ground connection (term. 31) is made via an eyelet in the connector housing and the engine fastening bolt Hydraulic pump – gear pump Coupling piece Pressure connection Cover with shaft seal, moulded seals and O-ring Pump housing Pump gears Pump housing Intake connection with O-ring Cover with moulded seal Hydraulic pump motor V387 613_109 Connector housing Sponge Pressure connection Pressure filter1) Spring1) Coupling piece Pressure accumulator Seal with integrated nonreturn valve Hydraulic pump 613_108 72 1) The pressure filter and the springs serve as a filter bypass valve Service Tow-starting/towing Tow-starting vehicles with R tronic (starting the engine without the starter) The Audi R8 with R tronic gearbox can be tow-started Tow-starting is generally not recommended There is a high risk of accident, e.g running into the towing vehicle Please follow the instructions given in the Owner's Manual Two-starting from a standing start: • Make sure that first gear is selected, and not reverse gear • Turn on the ignition, but not apply throttle • The pulling vehicle must drive away slowly and gently The gearbox shifts into neutral as soon as the engine is started The vehicle may only be tow-started for a very short distance, as otherwise unburnt fuel will be able to enter the catalytic converters If the engine does not start immediately, stop tow-starting the vehicle straight away Tow-starting on the move: • Turn on the ignition and put the gearbox into neutral • The pulling vehicle must drive away slowly and gently • Once the tow-starting speed has been achieved (approx. 5 – 10 kph), select a gear Depending on speed, the correct gear is engaged (e.g gear) Towing vehicles with R tronic If it is necessary to tow an Audi R8 with R tronic, the following conditions and restrictions must be observed: • Put the gearbox into neutral If this is not possible using the selector mechanism, follow the procedure described on page 56 • The max towing speed of 50 kph must not be exceeded • The max towing distance of 50 km must not be exceeded The gear oil pump is not driven while the vehicle is being towed This means that sufficient lubrication cannot be guaranteed if the vehicle is towed at excessively high speeds and for excessively long distances The vehicle must not be towed with the front or rear axle elevated Failure to observe the aforementioned points can result in severe damage to the front axle drive, the viscous coupling and the gearbox Towing vehicles with a manual gearbox The same conditions, restrictions and instructions as described under "Towing with R tronic gearbox" apply The gearbox shifts into neutral as soon as the engine is started The vehicle may only be tow-started for a very short distance, as otherwise unburnt fuel will be able to enter the catalytic converters If the engine does not start straightaway, stop tow-starting the vehicle immediately 73 Annex Index Index A F Actuators 70 Automated 6-speed manual gearbox 24 Automatic gearbox control unit 58 Auxiliary signals 63 F4 F36 Front axle drive 14 Function diagram 62 B G Basic gearbox 20 Basic settings 59 Blipping the throttle 13 Bypass thermostat 32 G182 68 G270 68 G476 67 G604 66 G616 66 Gear actuator 46 Gearbox in neutral 12, 46, 56 Gearbox input speed sender 68 Gear-changing 50 Gear oil cooling 32 Gear recognition 66 Gear recognition sensor 66 Gear set 26 C CAN information exchange 64 Centre differential 14 Change of shift gate 49 Close clutch 41 Clutch 34 Clutch actuator valve 70 Clutch adaptation 42 Clutch control 42 Clutch control–manual gearbox 35 Clutch control –R tronic 40 Clutch pedal switch Clutch position sender 67 Connectors 58 Cutaway view of gearbox 20 H Hydraulic control unit 36 Hydraulic diagram 38 Hydraulic pressure sender 68 Hydraulic pump 72 Hydraulic pump motor 72 D I DIS 13 Disengaging the clutch 41 Displays 60 Double plate clutch 34 Downshifts 13, 53 Drive-away characteristics 12 Drive concept Driver information system 13 Idler gear rattle 13 Ignition key removal lock 61 Internal shift mechanism 26, 46 E E541 10 Electro-hydraulic shift mechanism 46 Electromagnetic valves 70 Electronic control unit 58 Encode control unit 59 Engaging the clutch 41 Engine speed signal 69 J J104 64 J217 58, 64 J510 56 J527 61 J533 64 J587 10, 64 J623 64 J624 64 K Kisspoint 59 74 L S Launch Control Program 8, 13 Limited slip differential 20, 28 Limited slip value 29 Locking effect 29 Loss of signal 67 Lubrication 18 S-CAM/S-CAM brake 48 Selector lever sensors 10 Selector lever sensors control unit 10 Selector mechanism 11 Selector mechanism–manual gearbox Selector mechanism–R tronic 10 Selector overview–R tronic 36 Self diagnostics - shift matrix 55 Sensors 66 Shift adaptation 54 Shift adaptation - shift matrix 55 shift by wire Shift gate 49, 50, 52 Shift lock Shift matrix 54 Shift pattern 47, 49 Shift sequence–gear-changing 50 Specifications 15, 22 Sport mode 12 Starter control unit 61 Synchromesh 26, 27 M Manual and automatic gearboxes 20 Manual gearbox Manual mode 12 Mid-engine concept Multiple downshifts 53 N N255 70 N284 71 N285 71 N286 71 Neutral position 12, 46, 56 O Oil supply 18 Open clutch 41 Operating noise of R tronic 13 Operating R tronic 12 P Parking lock 12 Pressure build-up–hydraulics 39 Pressure holding–hydraulics 39 Q quattro R T TD signal 69 tiptronic 12 Towing 73 Tow starting 73 V V387 72 Viscous coupling 16 Viscous coupling operating instructions 19 W Warnings 60 Z Zero flow 70 Rear axle drive 20, 21, 28 Reversing lights switch F4 R tronic 10, 12, 13, 20, 24 R tronic gear actuator 36 R tronic hydraulic unit 36 75 613 Audi Vorsprung durch Technik Self Study Programme 613 For internal use only Audi R8 Power Transmission All rights reserved Technical specifications are subject to change Copyright AUDI AG I/VK-35 service.training@audi.de AUDI AG D-85045 Ingolstadt Technical status 03/12 Printed in Germany A12.5S00.97.20 Audi Service Training ... out more about the technology behind this power transmission system? If so, read on and learn all you need to know about power transmission in the Audi R8 613_007 This self study programme teaches... system in the Audi R8 has been implemented in a different way to previous Audi quattro drive systems In the case of the mid-engine concept with quattro all-wheel drive in the Audi R8, drive is... 6-speed manual gearbox 086 – R tronic Audi has elected to use an R tronic automated manual gearbox in the R8 R tronic is notable for its near-lossless power transmission, low weight and ultra-slick