Audi 2.7-litre V6 Biturbo Manual Download

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Summary of Contents for 2.7-litre V6 Biturbo

Page 1: ...ly 198 All rights reserved Subject to change AUDI AG Dept I GS 5 D 85045 Ingolstadt Fax 49 841 89 6367 740 2810 17 20 Technical status 01 98 Printed in Germany The 2 7 litre V6 Biturbo Design and Function Self study Programme 198 ...

Page 2: ...ine was to achieve a good level of dynamic response particularly at the bottom end of the rev band a further milestone in engine development by Audi The goal of AUDI s engineers was to realise a high basic torque level and a torque characteristic that rises in direct proportion to engine speed to its peak The term basic torque level describes the torque which is immediately available when the thro...

Page 3: ...tem pneumatically controlled systems charge pressure control air divert control in overrun ACF system crankcase breather 4 Motronic ME 7 1 Subfunctions system overview 31 Subsystems of the Motronic Torque oriented engine management torque oriented functional structure Electronic throttle exhaust gas temperature control 33 Sensors Additional sensors of the Motronic 49 Auxiliary signals interfaces 5...

Page 4: ...ower output This effect was principally achieved by modifying the software configuration of the engine control unit A tuning protective device prevents the S4 engine control unit being installed in the A6 This prevents misuse which can result in damage to the drivetrain An auxiliary heater is not available as an option for the S4 and the A6 due to the constraints on space BITURBO SSP 198 01 ...

Page 5: ...rder 1 4 3 6 2 5 Fuel type S4 98 95 91 RON A6 95 91 RON Compliant with emission standard EU III D Figures obtained using 98 RON unleaded premium fuel to 89 491 EEC Figures obtained using 95 RON unleaded premium fuel to 89 491 EEC 500 450 400 350 300 250 200 150 100 50 0 200 0 180 0 160 0 140 0 120 0 100 0 80 0 60 0 40 0 20 0 0 0 0 1000 2000 3000 4000 5000 6000 7000 SSP 198 02 Speed rpm Torque Nm O...

Page 6: ... to the side of the crankcase The lateral bolted connection helps to improve acoustics The pistons are forged to enable them to withstand the high loads to which they are subjected Due to the high combustion pressures a 2 material bearing shell is installed on the connecting rod side The bearing cap has a 3 material bearing shell Advantage The bearing shell has a high load bearing capacity SSP 198...

Page 7: ...dent To improve heat dissipation the exhaust valves are sodium filled The shape of the inlet duct causes the drawn in air to tumble Advantages A good degree of swirl and high ignitability fuel air mixture are achieved The tumble effect allows more efficient combustion For a turbocharged engine the compression ratio of 9 3 1 is high Advantage High basic torque level and fuel economy Tumble duct In ...

Page 8: ...is activated by the Motronic by means of camshaft adjustment valves N205 and N208 The design and function of the variable valve timing are already described in Self study Programmes 182 and 192 Activation of the variable valve timing is dependent on engine load and speed In the self diagnosis you can find out whether the variable valve timing is active or not by reading out the relevant measured v...

Page 9: ...nt thermostat through the radiator primary flow or through the oil cooler and expansion tank secondary flow Located in the cooling circuit is a electrical coolant pump This pump is required as a means of protection against overheating of the coolant under high thermal load e g when the hot engine is turned off Short circuit line Continued coolant function pump Heat exchanger Coolant Expansion tank...

Page 10: ...olant flows through the exhaust gas turbocharger and the cylinder heads The direction of flow in the turbocharger cooling circuit is reversed by this Due to this reversal of the direction of coolant flow coolant is drawn in via the cylinder heads large cross sections which means that any vapour bubbles which develop are expelled from the exhaust gas turbocharger lines The electrical coolant circul...

Page 11: ...elected Fan output level is controlled via pulse width modulated outputs Should a fan fail the radiator fan control unit increases the speed of the fan motor still available Advantages of the power control The series resistors previously used for power control are no longer required Lower power consumption in lower fan settings Safety functions The power supply is protected by a fuse on the 8 sock...

Page 12: ...n F129 Pressure switch for air conditioner only for vehicles with air conditioner V293 Control unit for radiator fan V7 Radiator fan induced air fan V51 Continued coolant circulation pump V177 Fan 2 for radiator forced air fan only for vehicles with air conditioner 1 Terminal 30 positive supply via fuse on 8 socket relay plate 2 Terminal 61 D alternator via fuse on 8 way relay 3 Fan activation onl...

Page 13: ...he fan motors run at 50 output is activated by air conditioning system pressure switch F129 The fan motors run at 85 output is activated by radiator fan thermoswitch F54 The fan motors run at full output Fan speeds 1 2 and 3 are only activated if the engine running signal is picked up at terminal 61 The electrical coolant function The continued coolant function is only activated if the engine not ...

Page 14: ...is fed to the oil filter via the oil cooler After passing an oil retention valve the oil flows through the filter element A bypass filter is connected in parallel with the filter element The oil subsequently reaches the main oil gallery A branch line is routed to the oil pressure control valve clean oil side The following components are supplied with oil from the main oil gallery the four cranksha...

Page 15: ...le level That aside piston cooling is not necessary at low engine speeds The spray jets valve SSP 198 57 Oil pressure control valve Oil pressure limiting valve Chain guard is an internal gear pump It is attached to the crankcase as a separate component The oil pump is designed in such a way that it projects deep down into the oil sump and is immersed completely in the engine oil when the oil level...

Page 16: ...f the oil filter and the cylinder heads and back into the oil sump while the engine is stationary The oil retention valves The integrated oil supply will also be adopted for all V6 5V naturally aspirated engines Each camshaft bearing is supplied via a drilling stemming from the cylinder head main gallery The oil is fed along a bolt shaft in the bearing cap to a transverse drilling A lubrication gr...

Page 17: ...t adjustment valve N208 Knock sensor G66 Intake air temperature sender G42 Knock sensor G61 Hall sender G163 Charge air cooler Charge air cooler Oil filter Oil pressure switch Air cond compressor Visco fan Alternator Power assisted steering pump drive ...

Page 18: ...alve Distributor piece Coolant temperature sender F18 F54 Camshaft adjustment valve N205 Exhaust gas temperature sender G235 with evaluation electronics Lambda probe G108 Exhaust gas temperature sender G236 with evaluation electronics Lambda probe G39 SAC clutch pressure plate Prim catal converter Prim catal converter ...

Page 19: ...r Fuel pressure regulator Solenoid valve for activated charcoal Solenoid valve for charge pressure control N75 Camshaft adjustment valve N205 Injector Hall sender G163 Divert air valve Charge pressure sender G31 Throttle valve control part Camshaft adjustment valve N208 Divert air valve ...

Page 20: ...iew of engine from left SSP 198 53 Injector Individual ignition coil Pressure control valve Prim catal converter Exh gas turbocharger Pressure unit for wastegate flap Oil cooler Oil filter Charge air cooler ...

Page 21: ...ge air coolers Cooling air intakes in the bumper and air vents in the wheel housing liners ensure that a sufficient amount of air flows through the charge air coolers Advantage of charge air cooling Cooled air has a higher density and this means improved volumetric efficiency The lower temperature reduces knock tendency also The compressed air streams then converge upstream of the throttle valve c...

Page 22: ... stress Since the turbochargers are flanged directly onto the exhaust manifold the exhaust gases travel less distance and there is less temperature loss As a result the catalytic converters are able to heat up more quickly and the efficiency of the exhaust gas turbocharger is improved by the favourable air flow Intake side of exhaust gas turbocharger Charge press side of exh gas turbo charger Exha...

Page 23: ...ss heat loss of the exhaust gas and less heat radiation in the engine compartment Weight saving Located downstream of each exhaust gas turbocharger is a primary catalytic converter close to the engine metal substrate Advantage The catalytic converters quickly reach a state of readiness for operation after a cold start The large surface area main catalytic converters ceramic substrate are located u...

Page 24: ...um ACF system The Motronic ME 7 1 activates the solenoid valve for the activated charcoal canister and regulates the fuel vapour feed rate to the engine via the vacuum Crankcase breather The crankcase breather controls the return of oil vapours to the engine via two mechanical valves Solenoid valve for charge pressure control N75 Solenoid valve for activated charcoal canister N80 Divert air valve ...

Page 25: ... The Motronic regulates the charge pressure of both turbochargers via the solenoid valve for charge pressure control G31 If a defect occurs in one of the cylinder banks e g melting of the catalytic converter or blockage of the exhaust system a purely air mass oriented charging system would still try to provide the computed air mass This would lead to an excessively high charge pressure In any case...

Page 26: ...sure acts directly on the pressure unit The waste gate opens even if the charge pressure is low If the charge pressure control fails the charge pressure is thus limited to a basic charge pressure in order to prevent the maximum permissible charge pressure being exceeded This results in a loss of performance The basic charge pressure is the charge pressure approx 300 400 mbar which is achieved with...

Page 27: ... air valves reduces the noise level in the induction tract and reduces fuel consumption The divert air valve N249 in combination with the vacuum reservoir enables the divert air valves to operate independently of the intake manifold pressure The system is designed in such a way that the pneumatic divert air valves continue to be opened by the intake manifold pressure if the electrically actuated d...

Page 28: ...d two non return valves The engine control unit assisted by solenoid valve N80 regulates the return rate of the fuel vapours from the ACF canister The Motronic operates the solenoid valve cyclically using a pulse duty cycle The non return valves control the return of fuel vapours depending on operating state ACF canister Solenoid valve for activa ted charcoal canister N80 Non return valve 2 Non re...

Page 29: ...e oil vapours and blow by gases return via the pressure limiting valve in the air distributor The pressure limiting valve limits the vacuum in the crankcase If the vacuum in the crankcase exceeds a defined value the diaphragm is drawn over the connection against the force of the spring and closes the connection The valve is designed in such a way that it allows a small quantity to pass through whe...

Page 30: ... control Mapped ignition Cylinder selective knock control Static high tension distribution with 6 individual ignition coils ACF system Torque oriented engine management Electrically actuated throttle valve Electronic accelerator Cylinder bank specific exhaust gas temperature control Mapped variable valve timing intake camshaft adjustment see chapter on Engine p 8 New New New New λ SSP 198 44 ...

Page 31: ...mp for electric throttle control K132 Auxiliary signals s Engine speed sender G28 l senders bank 2 G40 and bank 1 G163 a probes bank 1 G39 and bank 2 G108 Throttle valve control part J338 gle sender 1 G187 and 2 G188 for throttle valve drive G186 Intake air temperature sender G42 olant temperature senders G2 and G62 Charge pressure sender G31 k sensors bank 1 G61 and bank 2 G66 erator position sen...

Page 32: ...unctional structure This is made possible by the new electronic accelerator function Internal torque requests External torque requests Starting Idling speed control Catalytic converter heating Power limiter Driving comfort Components protection Engine governing Driver inputs Throttle valve angle Charge pressure Ignition angle Injection cut out Injection time Control variables influencing torque Dr...

Page 33: ...th regard to consumption and emissions so as to optimise torque control SSP 198 75 External and internal torque requests Calculation of efficiency and torque reference variables Prioritisation of charging path Prioritisation of crankshaft synchronous path Conversion of torque into charge Throttle valve angle Charge pressure control Calculation of crankshaft synchronous intervention Calculation of ...

Page 34: ...jection time The air mass necessary to develop a specific torque is determined by means of a calculation model and is made available along path 1 Path 2 is used to set the injection quantity or cylinder cut out necessary under the given circumstances and the optimal ignition angle Prioritisation of charging path Prioritisation of crankshaft synchronous path By and large long term torque requests a...

Page 35: ...y module Throttle valve control part J338 The accelerator position sender records the accelerator pedal angle and transfers it to the engine control unit The engine control unit adjusts the throttle valve by means of an electric motor A continuous stream of feedback signals on the position of the throttle valve is sent to the engine control unit Extensive security measures in hardware and software...

Page 36: ...ed fully while the accelerator pedal has not been fully depressed With electronic accelerator much improved emissions and higher fuel economy are achieved in specific load states Over and above this any accelerator characteristic can be programmed e g gradual acceleration when driving at low speed The electronic accelerator is used for reducing and increasing torque and does not adversely affect e...

Page 37: ... the Motronic and provides kickdown information to the automatic gearbox Lever Acc position sender Accelerator There is no separate switch for kickdown information Integrated in the accelerator position sender is a mechanical pressure point which conveys an authentic kickdown feel to the driver When the driver operates the kickdown the full load voltage of the accelerator position sender is exceed...

Page 38: ...t lamp for electric throttle control K132 comes on Emergency running program 2 If both accelerator position senders fail driver input recognition is not possible The engine only runs at idling speed The fault lamp for electric throttle control K132 comes on At idling speed the accelerator position senders G79 and G185 are not diagnosed If the plug of the accelerator position sender drops off no fa...

Page 39: ...hey have opposite impedance characteristics see diagram If an angle sender fails the second sender maintains the electronic accelerator function via an emergency running program Throttle valve housing with throttle valve Housing cover with electrical connections Throttle valve drive G186 Electric throttle control Angle senders for throttle valve drive G187 and G188 Resistance in Ω Angle senders G1...

Page 40: ... limit stop During operation the throttle valve closes no further than the lower electrical limit stop This prevents the throttle valve working its way into the throttle valve housing The emergency running position is the position of the throttle valve in the deenergised state and ensures that air flow is sufficient if any of the relevant electronic accelerator functions fails Idling speed is high...

Page 41: ... following three methods manually provided the ignition has been switched on for at least 24 minutes without operating the starter or accelerator automatically provided the need for adaption is acknowledged specifically by initiating basic setting 04 in measured value block 60 refer to Workshop Manual The upper electrical limit stop is defined in the control unit does not need to be learned As in ...

Page 42: ...ly also rough idling Driver inputs are executed as far as possible via the ignition angle and charge pressure The engine shows little response to the throttle The fault lamp for electrical throttle control K132 comes on Prerequisite Emergency running program 2 is only run if both angle senders for throttle valve drive recognise the emergency running position Emergency running program 3 If the thro...

Page 43: ... separate EPC fault lamp At the same time an entry is made in the fault memory When the ignition is turned on the fault lamp comes on and must go out again after 3 seconds if a fault state does not exist Fault lamp K132 is activated directly by the engine control unit via an earth potential If a fault occurs in the Electronic Accelerator System an appropriate emergency running program will be acti...

Page 44: ...ontinuous product improvement the accelerator position sender has been replaced by the accelerator pedal module The accelerator pedal module has already been used in other vehicle models within the Group Advantages of the accelerator pedal module Compact lightweight easy to assemble Modular technology Inexpensive to manufacture Module housing Housing cover and sensors For manual gearbox Stop buffe...

Page 45: ...place at 950 C for safety s sake This was achieved by enriching the air fuel mixture The exhaust gas temperature is recorded in a cylinder bank specific manner by the two exhaust gas temperature senders G235 and G236 The Motronic controls the exhaust gas temperature to 980 C by enriching the air fuel mixture It is therefore possible to largely dispense with the prophylactic enrichment process that...

Page 46: ...ng sensor generates into a pulse width modulated signal PWM signal This is a square wave signal with a fixed frequency and a variable pulse duty factor The pulse duty factor is expressed as a percentage The measurement range extends from 10 to 90 A specific pulse duty factor is assigned to each temperature refer to diagram Substitute function and self diagnosis A pulse duty factor of 1 or 99 is re...

Page 47: ...48 Notes ...

Page 48: ...iciency of engine power SSP 198 29 Charge pressure sender G31 The altitude sender F96 is integrated in the engine control unit as is normally the case with turbocharged engines is required to control the charge pressure In conditions of decreasing air pressure lower density the charge pressure is reduced to prevent the turbocharger overspeeding influences the air fuel mixture composition at engine...

Page 49: ...meter A partial airflow from the measuring pipe is fed past the sensor element through a measuring channel in the air mass meter housing The ascertained temperature values are evaluated in the evaluation electronics The Motronic applies a voltage proportional to the air mass to the air mass meter This voltage is needed to calculate the injection period and of actual engine torque Substitute functi...

Page 50: ... the upstream temperature sensor T2 is maintained due to the heated air in the heating zone Temperature sensors T1 and T2 indicate a temperature difference of T In the case of a return air flow the temperature difference occurs at temperature sensor T1 The amount and direction of this difference are therefore dependent on the incoming flow Advantage the differential signal permits a direction depe...

Page 51: ... lower heating capacity Note At an exhaust gas temperature as low as 150 C the probe heater generates the necessary minimum temperature of 350 C The lambda control is ready to operate approx 10 seconds after engine start up A porous ceramic protective layer is sintered onto the sensor element This layer prevents the sensor element being damaged by residues in the exhaust gas It ensures that the se...

Page 52: ...ignals initial injection and ignition are enabled By using Hall senders G163 and G40 as camshaft sensors the adjustment of both camshafts can be monitored closely and evaluated by the self diagnosis Substitute function and self diagnosis If Hall sender G40 fails Hall sender G163 takes on the task of synchronising first cylinder If both Hall senders fail it is possible to start the engine and the e...

Page 53: ...el The G28 recognises the engine speed Together with Hall sender G40 the G28 recognises the exact position of the engine mechanics i e ignition TDC of cylinder 1 The injection and ignition timing are determined using this information Substitute function and self diagnosis The signal which G28 generates is checked together with the signal supplied by the G40 for plausibility If the Motronic control...

Page 54: ...ll sender G40 bank 2 Engine speed sender G28 Diagram of signal of engine speed sender and the two Hall senders Hall sender G163 Hall sender G40 TDC of cylinder Engine speed sender G28 Hall sender G40 Here the signals which G40 G163 and G28 generate are shown combined for added clarity A two channel oscilloscope does not allow all three signals to be represented The TDC mark of the belt pulley refl...

Page 55: ... 15 It serves exclusively as an information input for the Motronic Substitute function and self diagnosis The two switches are cross checked for plausibility by the self diagnosis Please read the note on the Safety function on page 39 Clutch pedal switch F36 Wrong settings electrical malfunctions or maloperation driver keeps foot on clutch pedal may result in load change jolts or engine speed over...

Page 56: ... bus signal for automatic gearbox CCS set decelerate signal for cruise control system CCS Off signal for without cancellation cruise control system CCS On Off signal for with cancellation cruise control system master switch CCS Resume accelerate signal for cruise control system Road speed signal Immobiliser diagnosis signal Air conditioner compressor On Off signal Coolant temperature signal Engine...

Page 57: ...ignal calculated from the signal which coolant temperature sender G2 generates and a related temperature characteristic The signal is a data message and is connected to the earth potential when a temperature of approx 120 C is exceeded In this case the air conditioner s operating and display unit switches the compressor off along the bidirectional wire designated Air conditioner compressor On Off ...

Page 58: ... the higher engine load The interface as a signal output If the engine control unit applies an earth potential to the interface the compressor is switched off for a defined period of time as required The engine control unit switches the compressor off in the following situations After initiating basic setting function 04 In certain emergency running programs within a defined engine speed range The...

Page 59: ...per revolution of the engine is required by the following system components Dash panel insert Automatic gearbox Air conditioner The CAN high CAN low interfaces serve to transfer data between the control units The CAN data bus Controller Area Network is a serial data transfer system You can find detailed information regarding the CAN databus in SSP 186 1 2 20 40 60 3 SSP 198 61 1 revolution of engi...

Page 60: ...m CCS are linked to the controls on the steering column switch Cruise control is executed by the engine control unit by means of the electronic accelerator function Road speed can be kept constant as of approx 25 kph The CCS must be enabled or disabled using the login procedure function as with TDI engines When the control unit is enabled a G appears in the control unit identification refer to Wor...

Page 61: ... cylinder 2 N32 Injector cylinder 3 N33 Injector cylinder 4 N75 Solenoid valve for charge pressure control N80 Solenoid valve for activated charcoal canister N83 Injector cylinder 5 N84 Injector cylinder 6 N122 Output stage cylinder bank 1 N128 Ignition coil cylinder 2 N158 Ignition coil cylinder 3 N163 Ignition coil cylinder 4 N164 Ignition coil cylinder 5 N189 Ignition coil cylinder 6 N192 Outpu...

Page 62: ... B N122 A B B B 1 N192 G61 G66 G188 G187 G186 G79 F47 F36 F G163 G40 G62 G2 G42 K132 G185 G28 G70 G39 Z19 G108 Z28 Y Y I 2 3 4 5 6 7 8 9 10 11 12 II λ λ t t ml t t t Cruise control op switch from ignition lock terminal 15 to the brake lights terminal 30a Body earth Engine earth Note For the correct fuse rating please refer to the current flow diagram Body earth ...

Page 63: ...ting of diodes DMO Digital Memory Oscilloscope for representing the voltage curves of the various individual sensors and actuators Guided fault finding Vehicle and control unit identification A test plan is prepared on the basis of the fault messages issued by the the self diagnosis the fault description of customer complaints or assumptions regarding the cause of the trouble You will find introdu...

Page 64: ...ests to be performed while the engine is running VAS 5051 VAS 5051 SSP 198 65 VAS 5051 Test box V A G 1598 31 Engine control unit Earth The test leads V A G 1598 31 1 1 metre long and V A G 1598 31 2 2 5 metres long which are additionally screened give greater flexibility and protection against electromagnetic interference ...

Page 65: ...utch plate Greater wear reserve of the clutch plate For the biturbo engines Audi is using an SAC clutch pressure plate with a wear compensation feature for the first time SAC stands for Self Adjusting Clutch SSP 198 42 Auxiliary spring Adjusting ring Sensor plate spring Main diaphragm spring Compression spring Housing cover ...

Page 66: ...is required to transmit high levels of torque Higher contact pressures have to be applied to compensate for the limitations on the surface area of the clutch lining for design reasons This in turn results in higher releasing loads particularly as wear progresses Solution to problem If the position of the main diaphragm spring remains constant over the entire wear range the associated forces will a...

Page 67: ...iliary spring riveted to the housing cover The stop for release travel limits the travel of the release bearing and prevents unintentional adjustment of the adjusting ring The auxiliary spring counteracts the main plate spring as of a defined travel distance and ensures an even force curve during clutch engagement and disengagement SSP 198 70 Housing cover with auxiliary spring and stop for releas...

Page 68: ... to Workshop Manual The adjusting ring on new SAC clutch pressure plates is already reset The sensor plate spring and the adjusting ring locate mounting the main diaphragm spring SSP 198 73 after wear after wear Position as new Position after wear Position as new Position after wear Main plate spring mounting Main plate spring mounting Conventional clutch SAC clutch Adjusting ring ...

Page 69: ...so refer to load diagram is greater than that of the sensor plate spring the main plate spring will not come into contact with the adjusting ring The compression springs rotate the adjusting ring along the ramps in the housing cover In this way lining wear is compensated and the forces are again equalised SSP 198 74 Main diaphragm spring Sensor plate spring Housing cover Adjusting ring with ramps ...

Page 70: ...gine can be combined with the following gearbox versions at the customer s option Front wheel drive Manual gearbox 01E without oil cooling Quattro drive Manual gearbox 01E without oil cooling Front wheel drive Automatic gearbox 01V Quattro drive Automatic gearbox 01V Due to the two mass flywheel in combination with the SAC clutch a new 11 mm thick spacer ring is used for the manual gearboxes in be...

Page 71: ...72 Notes ...

Page 72: ...logy of the biturbo In the course of work on our corporate identity CI the Self study Programme now has a new format For example the SSP number is printed on the back page of the booklet so that you no longer need to take the booklet out of the folder when searching for it Please fax us your suggestions for improving the Self study Programmes on 49 841 89 6367 With the kind regards of your Technic...

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