Audi 4.0l V8 TDI engine of EA898 seriesSelf Study Programme 652For internal use onlyAudi Service Training BackAs a source of superior driving power in the premium segment, the V8 TDI engine offers high traction and ample power reserves in any driving situation. The new V8 TDI continues to follow this course. An electric powered compressor (EPC) contributes to good driveaway performance. The derivatives of the new engine generation will be available with the following features: • Power spread from 310 kW to 320 kW • Maximum torque of up to 900 Nm • Certification to EU6 (ZG) emission standard • Certification to EU5 and ULEV125 emission standards for export marketsForward Ξ ContentsIn addition to the main development targets, a key aim was to create a standard engine for all markets. The different emission standards are differentiated by the vehicle exhaust system. The state-of-the-art technologies described in this self study programme have been implemented with the following aims: • High engine power output and high torque for sporty positioning in an S model • Low fuel consumption for high efficiency in the high-performance segment • Low and sustainable emissions certified to EU6, EU5 and ULEV125 exhaust emission standards for world-wide use • Spontaneous power delivery and optimal drive-away performance as well as a high level of comfortLearning objectives of this self study programme: This self study programme describes the design and function of the 4.0l V8 TDI engine of the EA908 engine series. After you have completed this self study programme you will be able to answer the following questions:652_002• What is the structure of the components located in the inner V? • How is the coolant pump driven and how can it be switched off? • What is the voltage applied to the electric powered compressor (EPC)? • How does the charge pressure control system work?2ContentsIntroductionBrief description and special features _ ____________________________________________________________________________________________________________________ 4 Specifications _ ________________________________________________________________________________________________________________________________________________ 6 Engine concept with "inner hot side" _ _____________________________________________________________________________________________________________________ 7Engine mechanicalsEngine block __________________________________________________________________________________________________________________________________________________ 8 Timing gear __________________________________________________________________________________________________________________________________________________ 10 Cylinder head ________________________________________________________________________________________________________________________________________________ 12 Audi valvelift system (AVS) _ ________________________________________________________________________________________________________________________________ 13 Crankcase ventilation system ______________________________________________________________________________________________________________________________ 14Oil supplySystem overview ____________________________________________________________________________________________________________________________________________ 16 Oil circuit _____________________________________________________________________________________________________________________________________________________ 18 Oil filter ______________________________________________________________________________________________________________________________________________________ 18 Oil pump _____________________________________________________________________________________________________________________________________________________ 19 Oil cooling _ __________________________________________________________________________________________________________________________________________________ 19Exhaust gas recirculationOverview _____________________________________________________________________________________________________________________________________________________ 20 EGR cooler ___________________________________________________________________________________________________________________________________________________ 21Cooling systemSystem overview ____________________________________________________________________________________________________________________________________________ 22 Coolant module _____________________________________________________________________________________________________________________________________________ 24Air supply and turbochargingCombined design cover with integrated air filter ________________________________________________________________________________________________________ 27 Intake system _______________________________________________________________________________________________________________________________________________ 28 Intake manifold header ____________________________________________________________________________________________________________________________________ 29 Electric powered compressor (EPC) _______________________________________________________________________________________________________________________ 30 48-volt electrical subsystem _______________________________________________________________________________________________________________________________ 33 Charging group ______________________________________________________________________________________________________________________________________________ 34 Charge-air pressure control ________________________________________________________________________________________________________________________________ 35Fuel systemSystem overview ____________________________________________________________________________________________________________________________________________ 38 High-pressure fuel system _________________________________________________________________________________________________________________________________ 40 SCR system __________________________________________________________________________________________________________________________________________________ 41Exhaust systemOverview _____________________________________________________________________________________________________________________________________________________ 42 Exhaust gas treatment module ____________________________________________________________________________________________________________________________ 42 Ammonia slip catalyst (version for NAR) _________________________________________________________________________________________________________________ 43Engine managementSystem overview ____________________________________________________________________________________________________________________________________________ 44ServiceSpecial tools and workshop equipment _ __________________________________________________________________________________________________________________ 46AppendixSelf study programmes _ ____________________________________________________________________________________________________________________________________ 47The self study programme teaches a basic understanding of the design and mode of operation 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. This content is not updated. For further information about maintenance and repair work, always refer to the current technical literature.NoteReference3 BackForward Ξ ContentsIntroductionBrief description and special featuresSynergy with the 3.0l V6 TDI Gen2 evo• • • • Concept of the timing gear Concept of the cylinder heads Concept of the thermal management system Concept of the single-scroll high-pressure exhaust gas recirculation systemCO2 reduction measures• Innovative Thermal Management (ITM) 2 • Concept of a fully variable oil pump • Friction reduction through the use of coated piston rings and reduced preload • Friction reduction in the exhaust turbocharger rotor • Use of engine oil 0W-20Oil pump• Combined oil/vacuum pump integrated in the oil pan • Fully variable oil pump flow rate controlAudi valvelift system (AVS)• Located at the intake and exhaust endsChain drive for oil/vacuum pumpoil/vacuum pump652_032652_021Integrated oil filter• Installed in the oil pan behind a coverOil filter652_022Active engine mountings• Engine oscillation reduction652_088 4 BackForward Ξ ContentsHigh-pressure fuel system• Common rail injection system which delivers injection pressures of up to 2500 barCombined exhaust aftertreatment system• Common NOx oxidation catalyst (NOC) and SCR-coated diesel particulate filter installed in the inner V, i.e. near the engine652_017 652_023Turbocharging• Combination of active and passive turbochargers • Inner hot side • Switching of passive turbocharger via AVS on exhaust valve sideActive turbochargerPassive turbocharger652_019Electric powered compressor (EPC)• Complementary to conventional exhaust turbochargers • Powered by 48-volt electrical subsystem652_015652_024 5 BackForward Ξ ContentsSpecificationsTorque-power curve of 4.0l V8 FDI engine EA898 (engine code CZAC)   Power output in kW   Torque in Nm652_050The engraved engine code is located at the front left below the cylinder head on the protruding edge of the engine block as seen in the direction of travel.Engine speed [rpm]652_007Features Engine code Type Displacement in cm Stroke in mm Bore in mm Number of valves per cylinder Firing order Compression ratio Power output in kW at rpm Torque in Nm at rpm Fuel type Turbocharging Engine management Maximum injection pressure in bar Exhaust gas treatment Emission standard CO2 emissions in g/km1) 3Specifications CZAC 8-cylinder engine with 90° V angle 3956 91.4 83.0 4 1-5-4-8-6-3-7-2 16.0 : 1 320 at 3750 - 5000 900 at 1000 - 3250 Diesel to EN 590 VTG, active and passive turbochargers, e-actuator, electric powered compressor (EPC) Bosch CRS 3.25 2500 bar NOC (NOx oxidation catalyst), SCR-coated diesel particulate filter with integrated ammonia slip catalyst EU 6 (ZG) 189 – 1981)Depending on tyre size. 6 BackForward Ξ ContentsEngine concept with "inner hot side"The exhaust turbocharger and the exhaust gas recirculation system are integrated in the inner V of the engine. This compact layout follows a strict multi-level architecture which, thanks to a twinscroll exhaust manifold system, allows short gas flow paths and close-coupling of the exhaust gas aftertreatment system. This concept, with a "hot side" in the inner V, provides the basis for meeting fuel economy and emission targets. The exhaust gas recirculation system is located on the lowest level of the inner V. The EGR cooler with U-shaped throughflow, pneumatic EGR bypass valve and electric controlled EGR valve (exhaust gas recirculation valve GX5) has been optimised for minimal pressure loss.Components in the inner VExhaust manifold Charging groupActive turbochargerPassive turbochargerExhaust gas recirculation652_0447 BackForward Ξ ContentsEngine mechanicalsEngine blockEngine block GJV450 is a completely redesigned sand-core package casting. The positioning of the "hot side" in the inner V and the separate head-block cooling system have to a large extent defined the geometry of the engine block. The engine block has been designed with a systematic focus on reducing wall thickness The complex part of the media supply system to the oil/coolant heat exchangers is now separate from the engine block and integrated in a lightweight aluminium transfer plate. The split head block cooling configuration allows the coolant to stand inside the engine block at cold start, which results in ever faster warming up thanks to the low volume of the water jacket. The cylinder liners are plate-honed to attain an optimal cylinder shape during engine operation. This process is a basic requirement for reliable functioning of the piston rings with a low preload and is a key factor contributing to an optimal friction balance.Oil filter integrated in the oil panPistonsFor reasons of friction and strength, the aluminium pistons with salt-core cooling port are designed as sleeve pistons with a DLC1)coated gudgeon pin. After casting and premachining, the highly stressed bowl rim is re-melted by means of laser energy to produce the finest and strongest possible aluminium microstructure. The piston ring assembly was designed with a special emphasis on reduced friction. For example, lower piston ring preloads and piston ring heights are used. A combined system of PVD (physical vapour deposition) and DLC1) layers provides the required wear resistance of the first ring (control ring).Re-melted bowl rimSalt-core cooling ductDLC1) coated gudgeon pin1) LC stands for Diamond like Carbon, an amorphous carbon. D These strata exhibit very high hardness and are noted for having very low dry coefficients of friction. They can be identified by their glossy, black-gray surface.Pin bore bushing652_0268 BackForward Ξ ContentsEngine blockCoolant pump drive sprocketOil cooler (oil/coolant heat exchanger)Oil/vacuum pump652_025Transfer plateThe area to the oil/coolant heat exchangers has been separated from the engine block and integrated into a lightweight aluminium transfer plate.Transfer plateOil/coolant heat exchanger 2Oil/coolant heat exchanger 1652_008 9 BackForward Ξ ContentsTiming gearThe layout for the new V8 TDI engine has been taken from the V6 TDI engine family. The timing drive is, therefore, located on the flywheel side. To meet the high dynamic requirements of the high-pressure pump during use of the 2500 bar injection system, the chain drive for the high-pressure fuel pump is configured as a torsionally rigid twin-shaft drive which eliminates resonance and high chain forces across the entire rev band. In this engine the oil/vacuum tandem pump flange-mounted to the oil pan is driven directly from the front end of the crankshaft via a separate chain track.Previous chain driveNew-generation chain drive652_027High pressure fuel pumpChain drive Fuel pumpDrive shaft Coolant pump Timing gear Chain drive Oil/vacuum pumpOil/vacuum pump652_028 10 BackForward Ξ ContentsCamshaft driveAn intermediate gear mounted in the cylinder head provides a 2:1 ratio without the need for large camshaft sprockets. Taking this intermediate gear as the starting point, camshaft drive is provided by a downstream double gear-wheel stage with each gear wheel having backlash compensation for acoustic reasons. To minimise friction in these additional bearing points, the intermediate gear mounting takes the form of a needle bearing. To provide greater robustness in terms of oil quality and different oil viscosities, the Audi V configuration diesel engines exclusively use bush chains with chrome-plated pins.Spur gear step with backlash compensationSupport for omega spring connecting to fixed gear Idler gearSprocket Omega springNeedle bearingFixed gear652_029IdlerBacklash compensationRecess in the fixed gear Omega springBacklash is compensated by the omega spring, which engages the recess in the fixed gear and is preloaded by a spring guide in the idler. When the camshaft gear is installed, it is relieved of stress by an excentric bolt and engages the drive wheel with a degree of play. On completion of assembly, the excentric bolt is removed. The spring force rotates the two gears towards each other, and the gear runs without backlash in the drive sprocket.Hole for insertion of the excentric bolt during assemblySnap ring CamshaftFixed gearIdler652_074 11 BackForward Ξ ContentsCylinder headThe high demands imposed on the cylinder head in terms of power output and maximum cylinder pressure have been met by means of an axle-parallel, symmetrical valve star and a two-part water jacket. In order to eliminate micro-notching effects in high-stress zones, the coolant jacket and the intake ducts have been optimised with respect to their parting burr characteristics. The objective was to eliminate mould parting burrs from highly stressed areas and to allow these areas to be deburred reliably and automatically. The structural design of the cylinder head has been adapted to the engine concept with the "hot side" of the cylinder head located in the inner V. In conjunction with other structural improvements, this makes both cylinder heads about 7.0 kg lighter than in the predecessor engine.Intake cam adjusterFuel injectorMovable cam elementRoller-type cam follower Exhaust duct to passive turbocharger Glow plug Exhaust duct to active turbocharger652_030Cooling jacketUpper coolant jacketThanks to very fast flow rates, the lower water jacket ensures intensive cooling of the combustion chamber plate and the highly stressed valve webs. Despite the gain in performance, web temperatures have been reduced by as much as 30° C compared to the predecessor engine with a single-part water jacket. In the upper water jacket requiring less cooling, slow flow rates prevail in order to minimise the water-side pressure losses.Lower coolant jacket652_031Vent ductIf leaks occur in the area of the injector ring seal, a vent duct allows the combustion pressure to escape. This duct is integrated in the cylinder head above the intake module. It prevents excess pressure from the combustion chamber escaping via the crankcase ventilation system to the compressor side of the turbocharger and causing the turbocharger to malfunction, or damaging the ring seals or blowing them out of the crankcase.Vent duct12652_065 BackForward Ξ ContentsAudi valvelift system (AVS)The Audi valvelift system (AVS) is the core element of the multistage turbocharging system. The system had been used previously in the petrol engines of the VW Group and has been improved to meet the general operating requirements of the diesel engine. Due to the position of the injectors and the alignment of the valves perpendicular to the combustion chamber plate, the basic shaft of the AVS is mounted between the individual cylinders. The basic shaft has a spline which accommodates the individual, axially displaceable cam elements. The pins of the electromagnetic actuator (cam adjuster) engage the gate of the cam element and move it axially between the two cam shift positions. Two different cam contours are used on the intake side to vary event duration with the aim of maximising drive-way performance while generating the required power output by means of long valve opening times, short valve timings for drive-away performance (opening angle of 160 crank angle degrees) and long valve timings for power (opening angle of 185 crank angle degrees). Thanks to variable intake valve timing, it has been possible to achieve an optimised intake valve lift curve which provides good response at low engine speeds and volumetric efficiency at high engine speeds. This combination, together with leakage-free switch-over between the two exhaust turbochargers and variable exhaust valve timing, results in significantly better spontaneity.Intake endIntake cam adjusterExhaust endInjector Cam elementCam elementExhaust cam adjusterGlow plugActive exhaust valve for multi-stage charging163 crank angle deg.652_075185 crank angle deg.652_032 13 BackForward Ξ ContentsCrankcase ventilation systemThe 4.0l V8 TDI engine is equipped with an efficient crankcase ventilation system consisting of a crankcase breather module and blow-by gas ducts leading into the cylinder head covers. The blow-by gases rising up out of the crankcase are collected at the centre of the cylinder head covers and ducted through the coarse oil separator. This separator consists of multiple ascending steps (settling chambers) which are responsible for initial separation of the oil and air in the blow-by gases. The blow-by gases subsequently reach the fine oil separators, of which there is one in the left cylinder head cover and two in the crankcase breather module. The blow-by gases are ducted through a labyrinth into the two fine oil separators with swirls, which are installed horizontally and vertically in an enclosed housing. The remaining oil residues are thereby separated. The separated oil flows along several discharge ducts and into the oil pan above the oil level. The oil-free blow-by gases flow through the pressure control valve to the intake end of the active turbocharger and are admitted into the combustion chamber.OverviewFine oil separator Treated blow-by gases to the intake end of the active turbochargerCrankcase breather module with 2 fine oil separatorsOil returnVent tube with fixed connectionCylinder head cover with integrated fine oil separator652_009 14 BackForward Ξ ContentsCrankcase breather moduleThe crankcase breather module is located at the back of the engine. In it are integrated the two fine oil separators for the righthand cylinder bank, the pressure control valve and the oil return line from the fine oil separator of the left-hand cylinder bank.Treated blow-by gases to the intake end of the active turbochargerFine oil separator for the left cylinder bankNon-return check valve A non-return check valve, installed in the oil return line from the crankcase breather module, ensures that oil cannot be drawn into the intake area from the oil pan in situations such as icing-up of the crankcase breather.Blow-by gases from the left cylinder bankOil return from the left cylinder bankPressure control valve Fine oil separator for the right cylinder bank Oil return to oil panBlow-by gases from the right cylinder bankNon-return check valve652_014Fine oil separatorIn terms of their working principle, the fine oil separators are centrifugal separators - or what are known as axial swirls (PolyswirlTM). Each of these separators consists of 8 permanently open swirls and 2 packs of 8 swirls which are activated and deactivated depending on volumetric flow. The two packs are activated and deactivated by action springs with different spring characteristics. The fine oil separator is opened by the blow-by gas flow in dependence on engine speed. The spring force of the action springs is used for closing.Action springsPermanently open swirlsCleaned blow-by gas SwirlSeparated oilBlow-by gas inlet (raw gas)Pack of 8 swirls (flow-dependent opening)Permanently open swirls652_016 15 BackForward Ξ ContentsOil supplySystem overviewKey: A B C 1 2 3 4 5 6 7 8 9 10 11 12 13 Camshaft bearing Support element Main bearing Exhaust turbocharger 1 Exhaust turbocharger 2 Flow restrictor Oil/coolant heat exchanger 1 Oil/coolant heat exchanger 2 Oil filter module Chain tensioner pinion A: Chain tensioner pinion D: Piston cooling nozzle Non-return valve Oil pressure control valve N428 Controlled oil pump Vacuum pumpAAAAABBBBBBBBAAAAABBBBBBBBCylinder head 234 65High pressure circuit Low pressure circuit101010121316 BackForward Ξ ContentsAAAAABBBBBBBB12AAAAABBBBBBBBCylinder head 137 89999C 11CCCCEngine blockOil pan652_00517 BackForward Ξ ContentsOil circuitPassive turbochargerActive turbochargerOilways for supplying the camshafts and the support elementsChain tensionerMain oil galleryPiston cooling jets Oil pressure switch F22 Oil/coolant heat exchanger 2 Oil filter module (in oil pan) Oil/coolant heat exchanger 1Oil pressure control valve N428Oil/vacuum pump652_047Oil filterDue to the constraints on space, the oil filter has been installed inside the oil pan. The oil filter is accessible through a sevice cover on the oil pan.Oil filter cartridgeService cover on the oil filter with sealService cover on the oil pan with seal652_010 18 BackForward Ξ ContentsOil pumpThe oil circuit uses the fully variable oil pump of the V6 TDI engine, which has been adapted to the oil demand of the V8 TDI engine. The vane pump, continuously controlled by way of an eccentric ring, permits optimum adaptation of the pressure/volume flow depending on engine load and speed. Additionally, the throughput of the piston jets can be influenced, or shut off, by way of the pressure map in order to optimise friction.DesignFlutter valve Rotor with vane cellsValveVacuum pump coverRotor with vacuum pump vane Input shaft Adjustment ring with control spring Oil pump coverCold start valveIntake manifold Oil strainerOil coolingTo allow the oil to heat up oil quickly after a cold start, volumetric flow to the oil/coolant heat exchangers takes place on the coolant side. There is no coolant flow through the oil/coolant heat exchangers during the cold start phase and at low engine loads. It652_052is not until a certain, evelated oil temperature is reached that coolant flow through the oil/coolant heat exchangers is enabled by switching the oil cooler valve.Transfer plateOil/coolant heat exchanger 2Oil/coolant heat exchanger 1652_008 19 BackForward Ξ ContentsExhaust gas recirculationOverviewIn a combustion process involving surplus air, unwanted nitrogen oxides form at high combustion chamber temperatures in any internal combustion engine. The formation of nitrogen oxides can, to a large extent, be avoided by recirculating the exhaust gases. The exhaust gas recirculation system directs a portion of the exhaust gases back into the combustion chambers. This reduces the amount of fresh, oxygen-rich air in the exhaust gases thereby inhibiting the chemical reactions within the combustion chamber. The resultant reduction in combustion temperatures in turn means significantly lower NOx emissions.Exhaust gas extraction point on active turbochargerActive turbochargerExhaust gas recirculation pressure sensor G691Exhaust gas recirculation valve GX5Charge air pipeEGR cooler652_062Exhaust gas inlet in the charge air pipe20 BackForward Ξ ContentsEGR coolerCoolant flowDue to the gas flow configuration in the EGR cooler, double the distance of the EGR cooler is utilised. The exhaust gases from the exhaust manifolds flow in a U shape from the bottom to the top section of the exhaust gas recirculation cooler. The gases flow through the coolant tubes and dissipate their heat to the coolant. To enlarge the cooling surface area, the gas-carrying pipes are embossed. The cooled coolant flows into the EGR cooler at the hot exhaust gas inlet. This results in so-called "continuous flow cooling" at the bottom end of the EGR cooler and "counterflow cooling" at the top end of the EGR cooler.EGR cooler Exhaust gas outlet Exhaust gas inletCoolant outletCoolant inletGas-carrying pipes with embossingsExhaust gas recirculation valve GX5652_066Bypass modeA key feature of the external exhaust cooling system is that the exhaust gases on the exhaust side of the engine are extracted from the exhaust manifold and returned to the combustion process. When the engine is cold, the hot exhaust gases are channelled directly into the charge air system via the bypass duct. This ensures rapid heating of the oxidising catalytic converter and of the engine.Cooling modeTo reduce nitrogen oxide emissions still further, the exhaust gases are additionally cooled via the liquid-controlled exhaust gas recirculation cooler. The EGR bypass valve, activated by the EGR cooling bypass valve N386, opens the inlet to the EGR cooler. The exhaust gases are now channelled through the cooled pipes and dissipate their heat to the coolant. This allows the combustion chamber temperature to be reduced thereby ensuring lower NOx levels in the exhaust gases.Pneumatic EGR bypass valveExhaust gas inletPneumatic EGR bypass valveExhaust gas inletTo EGR inlet on charge air pipeExhaust gas recirculation valve GX5To EGR inlet on charge air pipeExhaust gas recirculation valve GX5Cooler bypass valve openCooler bypass valve closedEGR coolerCoolant outletEGR coolerCoolant outlet652_045652_04621 BackForward Ξ ContentsCooling systemSystem overview12V488 N509 34 N4746 5 7 10 9812 G8 G812 11 13 14 15 16/F265 15 17G621518G831920J671J293V64521 15652_00422 BackKey to figure on page 22: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 Front heater heat exchanger Rear heater heat exchanger ATF cooler Exhaust turbocharger 1 Coolant expansion tank Cylinder head, bank 1 Cylinder head, bank 1 Cylinder head, bank 2 Cylinder head, bank 2 EGR cooler Exhaust turbocharger 2 Oil/coolant heat exchanger 1 Oil/coolant heat exchanger 2 Coolant pump Non-return valve Rotary slide valve with electrically heated wax expansion element Oil cooling circuit control valve Electric powered compressor (EPC) Head block cooling circuit control valve Flow restrictor RadiatorForward Ξ ContentsF265 Thermostat for mapped engine cooling G8 Oil temperature sensor G62 Coolant temperature sensor G83 Coolant temperature sensor at radiator outlet G812 Coolant temperature sensor 3 J293 Radiator fan control unit J671 Radiator fan control unit 2 N474 Reducing agent injector N509 Gearbox oil cooling valve V488 Heating assistance pump V645 Electric compressor coolant pumpCooled coolant Warm coolantComponents on the enginePassive turbochargerEGR coolerActive turbochargerEGR valve GX5VentThermostat for mapped engine cooling F265 Return line Coolant coolerCoolant moduleOil cooler circuit control valve Head block cooling circuit control valve Radiator supply lineCoolant pump652_040 23 BackForward Ξ ContentsCoolant moduleThe innovative thermal management concept permits autonomous supply to the interior and gearbox oil heating, the EGR cooler and the exhaust turbocharger via the cylinder head circuit, regardless of the coolant standing in the engine block. Coolant flows through the engine block and cylinder heads in two parallel cooling circuits. The coolant flow for both circuits runs from the hot inner V intake across the engine block or cylinder head to the cold outer side. The water pump located in the inner V now has a covered impeller with three-dimensionally curved blades, and continuously supplies the two sub-circuits. The coolant pump is driven by a drive shaft integrated in the timing gear via a sprocket. The coolant module, in which key functional components of the coolant circuit are integrated, is installed at the front end of the engine. The volute casing of the coolant pump forms the coolant module. The map-controlled thermostat with rotary slide valve and electrically heated wax expansion element for switching the large cooling circuit is flange-mounted to the coolant module on the supply side. Also integrated in the coolant module are the head block control valve, activated by the pressure reducing valve N155, and the oil cooler bypass valve, activated by the EGR cooling bypass valve 2 N387 in a pulse width modulated fashion using vacuum.652_060Coolant module with coolant pumpDesignSupply line to engineCoolant pumpOil cooling circuit control valveHead block cooling circuit control valveRotary slide valve (open)Return from engineIntake to radiatorThermostat for mapped engine cooling F265Return from radiator652_03924 BackForward Ξ ContentsMap-controlled thermostat with rotary slide valve and electrically heated wax expansion elementThe temperature level of the cylinder head cooling circuit is controlled via a mapped thermostat with a heated wax expansion element. The thermostat is de-energised during the warm-up phase and opens at 90 °C. Thus, no thermal energy is dissipated to the main radiator in order to achieve this temperature. Hot coolant is provided for heating the ATF oil and for heating as necessary. The temperature level of the cylinder head cooling circuit can be reduced – within the physical bounds of the radiator – by energising the map-controlled engine cooling thermostat.Actuation of the rotary slide valveDeflection point Rotary slide valve open Coolant flow is enabled Sliding element with spring Wax expansion elementGuide rodElectrical connection for heating the wax expansion elementControl piston actuates the sliding element against the pressure of the spring652_070The wax expansion element is a pressure-resistant cell filled with a wax-like expanding material. An integrated heater melts the expanding material in the wax expansion element, causing the volume of the latter to increase significantly. As a result, the control piston pushes outwards and the sliding element moves against the pressure of the spring. The sliding element connectedto the rotary slide valve is now guided along a guide rail. The linear movement of the sliding element is translated to a rotational movement of the rotary slide valve at a deflection point. This causes the rotary slide valve to open or close. The expanding material contracts when it cools down again and the spring-loaded control piston closes the rotary slide valve.Thermostat closedThermostat open652_042652_041Coolant temperature sensor at radiator outlet G83Coolant temperature sensor G6225 BackForward Ξ ContentsPnuematically actuated control valves (rotary piston valves)There are two coolant valves on the coolant module. In terms of their working principle, both are pneumatically activated rotary piston valves with the following functions. Head block cooling circuit control valve Firstly, the cylinder block cooling circuit is positioned above the coolant outlet, the vacuum-controlled rotary piston valve is shut off and operated with standing coolant in order to shorten the warm-up phase of the engine and reduce friction at the crank mechanism. After the engine has heated up, the temperature level in the cylinder block cooling circuit is adjusted to approx. 105 °C by means of the vacuum-controlled rotary piston valve. The crankgear can, thus, be operated in the ideal temperature range in frictional terms. To this end, the rotary piston valve is activated by the pressure reducing valve N155 in a pulse width modulated (PWM) fashion. Oil cooling circuit control valve To promote rapid heating of the engine, the concept provides for oil cooler throughflow on the oil side. To this end, the rotary piston valve is activated by EGR cooling bypass valve 2 N387 in a pulse width modulated fashion. To allow the oil to heat up oil quickly after a cold start, volumetric flow to the oil/coolant heat exchangers takes place on the coolant side. There is no coolant flow through the oil/coolant heat exchangers during the cold start phase and at low engine loads.Function for head block cooling circuitRotary piston valve closedLinkage Vacuum cellVacuum Rotary piston, closed652_012Rotary piston valve openCoolant flowAtmospheric pressure Rotary piston, open26 652_011 BackForward Ξ ContentsAir supply and turbochargingCombined design cover with integrated air filterThe design cover, which acts as the air filter cover, is a multi-part welded construction. The bottom part of the design cover houses the air filter base attached to the engine with air filter cartridges, the connections to the turbochargers and the suspension geometry for the oil filler tube. The two air mass meters G70 and G246 are also integrated. The air filter housing has two connecting ports on the raw air side at the front end of the engine. Drainage of the air filter housing is provided by an integrated multi-outlet water discharge system which provides for reliable drainage while driving in spray/rain and during offroad operation on inclines within the permissible operating parameters. The main drainage system is atmospherically controlled (water outlet hose). As the engine has a very high demand for air, no bypass flap is installed in the air filter. The inflowing moist air precipitates on the inner left and right deflecting surfaces which also protect the air filter cartridge against ingress of moisture.OverviewTwo-piece design cover (air filter cover)Oil filler tubeIntake manifoldAir mass meter 2 G246Air filter box Deflecting surfaceAir filter cartridgesAir mass meter G70Air intake from the front end Intake manifold with silencer652_058 27 BackForward Ξ ContentsIntake systemCharge air flowThe charge air flows from both turbochargers merge in an X-shaped distributor piece, after which they are separated into equal partial flows and channelled to the left and right charge air coolers via an IHPF aluminium pressure tube. The electric powered compressor (EPC) is integrated in the left-hand charge air system aft of the charge air cooler, albeit still close to the engine, and is operated via a pneumatic bypass flap in dependence on the operating point. The partial charge air flows merge again in an aluminium sand-cast charge air pipe on the front end of the engine downstream of the throttle flaps. The centrally inserted slotted EGR pipe here ensures that the recirculated exhaust gases are effectively mixed with the fresh air. The design of the charge air pipe ensures an even distribution of the charge air to the intake air headers on the outside of the cylinder heads. An integrated system of swirl control by means of a single flap per cylinder is implemented on bank-by-bank basis using an electric actuator (intake manifold flap motor 1 V157 or intake manifold flap motor 2 V275).System overviewPassive turbochargerPressure line between the turbochargers Right charge air cooler Active turbochargerCompressor sequence valveIntake air temperature sensor G42Charge air pipe (aluminium sand casting)X-shaped distributor piecePressure line between the turbochargersThe pressure line from the active charger outlet to the turbine Passive turbocharger shaft of the passive turbocharger is required for sealing the bearing shaft. When the system is in preparation for biturbo mode, vacuum is briefly present after opening the recirculation valve. Given that this vacuum would draw off the bearing oil in the turbine shaft, the charging pressure of the active turbocharger is used to build up pressure in the interstice between the two sealing rings thereby compressing the sealing rings against the housing and sealing it.Pressure line Sealing rings on the turbine shaftCharge air recirculation module GX37 (recirculation valve)Active turbocharger652_07128 BackForward Ξ ContentsIntake manifold headerAn integrated system of swirl control by means of a single flap per cylinder is implemented on bank-by-bank basis using an electric actuator (intake manifold flap motor 1 V157 or intake manifold flap motor 2 V275). Swirl is controlled by means of 8 swirl flaps in the new 4.0l V8 TDI engine. The ports, which are fitted with a swirl flap, duct the air into the filling ports and the ports without a swirl flap duct the air into the swirl ports. This ensures that the air always flows via the swirl ports at low engine speeds and via both intake ports under load when the swirl flap is open.Intake manifold flap control unit GX14 bzw. Intake manifold flap control unit 2 GX15 with: intake manifold flap motor 1 V157 or intake manifold flap motor 2 V275Charge air outlet to the combustion chambersCharge air recirculation module GX37 (recirculation valve) Intake manifold flap shaft1 intake manifold flap per cylinderIntake manifold header (bottom section)652_013Charge air intakeIntake air temperature sensor 2 G299Electric powered compressor (EPC) with electric compressor control unit J1123Left charge air coolerEPC bypass valve652_03529 BackForward Ξ ContentsElectric powered compressor (EPC)The electric powered compressor (EPC) consists of the compressor and electric motor modules. They are jointly housed in a common housing which also accommodates the electronics in a separate housing. It has the service designation electric compressor control unit J1123. The EPC is installed below the left headlight on the charge air cooler. Specifications of the electric powered compressor: Drive output of electric motor Maximum compressor speed Maximum spool-up time 7 kW 70,000 rpm 250 msDesignElectronics housingCooling jacket Electric compressor control unit J1123StatorRotor Compressor wheel652_049Shaft bearing The maximum RPM, in conjunction with high speed gradients, requires a specially rated bearing. The shaft with compressor wheel and rotor is supported in the housing by a fixed-loose bearing with maintenance-free greased ball bearings.Method of operation The difference between the actual and computed dynamic nominal charge pressures is determined from the charge pressure differential to be produced by the electric powered compressor. If a defined threshold value is exceeded, the electric powered compressor is activated. The charge pressure model for the engine and the nominal value generator in the electric powered compressor subsequently interact with one another. The use of the electric powered compressor further increases the acceleration capacity of the turbines and the compressor of the active turbocharger. The electric powered compressor is deactivated again when the stationary nominal charge pressure is sufficient for meet the engine's operating requirements. It continues to run in standby mode at a speed of approx. 5000 rpm. The electric powered compressor is encapsulated in order to reduce noise.30 BackForward Ξ ContentsLine connections on the electric powered compressorDue to the high speeds at which the engine runs, the electric powered compressor requires additional cooling. For this purpose, it is integrated in the engine coolant circuit and is fitted with coolant connections. In addition to the terminals for the 48-volt electrical system (refer to page 33), the electric powered compressor has a further electrical terminal which communicates with the electric powered compressor control unit J1123 and the engine control unit J623 via the sub-bus system.On the underside: vacuum connection to intake hoseConnection for Signal line Connections for 48-volt electrical subsystemCoolant outflow Coolant inflowPre-compressed air from active charger – inflow via the charge air coolerPre-compressed air – outflow into the charge air bypass652_069Vacuum connection from EPC to active charger return lineNote To stop the blow-by gases in the charge air system from entering the electronics, a pressure line connected on the underside of the electric powered compressor continuously extracts the accumulated oil from the housing.31 BackForward Ξ ContentsInteraction of the charging group with the electric powered compressor (EPC)The electric powered compressor is active at the start of acceleration and assists driving away from a standing start. The engine runs in monoturbo mode. Only the active turbocharger is driven via the corresponding manifold scroll. The air mass flow is increased directly by the electric powered compressor and provides a fullthrottle injection rate which, given the same air ratio, is significantly higher than during operation without an electric powered compressor. The illustration shows by way of example graphs of acceleration with and without assistance by the electric powered compressor (EPC).Torque [Nm]EPC activewith EPC without EPCTime [s]Car with EPCTime [s] Car without EPCDistance covered652_07232 BackForward Ξ Contents48-volt electrical subsystemThe very high demands on the dynamics of the electric powered compressor result in peak electrical power outputs of up to 7 kW The electric powered compressor receives its energy from an electrical subsystem which is configured as a power island. This amount of energy is provided by a separate 48-volt electrical subsystem, which is coupled to the conventional 12-volt electrical system via a DC-DC converter. A compact 10 Ah lithium-ion battery is used as an energy accumulator. The 12-volt electrical system is supplied by a 200A generator.In-car componentsPower distributor for terminal 40 TV66Power distributor 2 for terminal 40 TV67Torque converter, 48 V/12 V A7Battery, 48 V A6Roll stabilisation control unit 2 J1096Electrically powered compressor J1123652_090Circuit 12 volts 48 volts12-volt starter12-volt power consumer 12 volt generator 12-volt battery48-12 volt voltage converter 48-volt power consumer48-volt battery652_089Reference For more information about the 48-volt electrical subsystem, refer to Self Study Programme 651 "Audi Q7 (type 4M)".33 BackForward Ξ ContentsCharging groupThe charging group consists of the following components: • Active turbocharger with access to exhaust gas recirculation system • Passive turbocharger with compressor sequence valve • Recirculation valve Both turbochargers are regulated by speed control of charge pressure actuators.Bracket of the passive turbochargerExhaust turbocharger speed sensor 2 G689Exhaust turbocharger control unit 2 J725 with V546Passive turbocharger Compressor sequence valve Exhaust gas temperature sensor 1 for bank 2 G236 Charge air pipePressure line between the turbochargersCharge air recirculation module GX37 (recirculation valve)Exhaust gas temperature sensor 1 G235Active turbochargerExhaust turbocharger speed sensor 1 G688Exhaust gas turbocharger control unit J724 with V465Bracket of the active turbochargerConnecting socket of the crabkcase breather Intake tubeIntake hose with silencer652_064Charge air recirculation module GX37 (recirculation valve)To ensure rapid spool-up of the passive turbocharger and to avoid a sudden loss of drive power to the active turbocharger, the recirculation valve is opened and the pre-compressed air from the passive turbocharger is ducted into the intake section of the active turbocharger.Charge air recirculation module GX37Rotatable flap of the recirculation valve652_068 34 BackForward Ξ ContentsCharge-air pressure controlTo facilitate switching between the active and passive turbochargers, the exhaust gases from the two exhaust valves of each cylinder flow to both turbines in two separate scrolls – the active scroll and the passive scroll. This systematic separation of the exhaust scrolls into two per cylinder bank allows complete thermal decoupling of the active and passive exhaust scrolls where a steady flow through the active turbocharger is always maintained. The passive turbocharger is used at engine speeds of over 2700 RPM. Each cylinder bank has two integrally insulated exhaust manifolds made of cast steel.Passive turbocharger Active turbochargerInterconnection of the cylinder banks The two cylinder banks are interconnected by integrally insulated exhaust pipes. To achieve an optimal balance in terms of thermal expansion, the design is a composite of Inconel decoupling elements as well as cast steel pipe and flange geometries. InconelTM is a trademarked brand name for corrosion resistant nickel-based alloys designed specially for high-temperature applications.652_067Monoturbo modeOn the exhaust end, the AVS switches a cam without valve lifter in position 1 for the exhaust valves of the passive exhaust scroll with the result that one exhaust valve stays closed per cylinder.Biturbo modeIn switching position 2 a cam contour with valve lifter opens the exhaust valve so that the engine runs in biturbo mode.Movable cam memberPassive scrollActive scrollActive scroll652_033652_034Operating ranges Key:1 3 1 Monoturbo mode 2 Temporary activation range of the EPC 2 3 Biturbo mode 4 Switch-over transition range   Power output in kW 4   Torque in NmEngine speed [rpm]652_091 35 BackForward Ξ ContentsMonoturbo mode with electric powered compressor (EPC)The electric powered compressor is active at the start of acceleration and assists driving away from a standing start. The engine runs in monoturbo mode. Only the active turbocharger is driven via the corresponding manifold scroll. The air mass flow is increased directly by the EPC and provides a full-throttle injection rate which, given the same air ratio, is significantly higher than during operation without an EPC. The higher heat content of the exhaust gas not only increases engine torque directly, but also enables the active turbocharger to spool up much more quickly. Maximum charge pressure is achieved 1 second earlier, and there is a noticeable increase in the engine torque available from idle speed upwards.Exhaust valves with AVS OFFRecirculation valve closedActive turbochargerCompressor sequence valve closed Electric powered compressor (EPC)EPC bypass valve closedThrottle valve in charge air pipe closed652_037Monoturbo modeWhen the active turbocharger reaches its full performance level, it switches the electric powered compressor (EPC) off. The engine continues to run in monoturbo mode and, thanks to the highly dynamic active turbocharger, is able to utilise fully the advantages of multi-stage charging.Exhaust valves with AVS OFFRecirculation valve closedActive turbochargerCompressor sequence valve closedEPC bypass valve eopnThrottle valve in charge air pipe open36652_036 BackForward Ξ ContentsMonoturbo mode in preparation for biturbo modeTo utilise the full performance potential of the engine at high engine speeds, the engine enters the multi-stage transition mode and is prepared for activation of the passive turbocharger as of about 2,000 RPM. The individual exhaust valves (firing order) leading to the manifold scroll of the passive turbocharger open gradually so that the passive turbocharger is spooled up without a sudden reduction in drive power to the active turbocharger. This process takes place with the recirculation valve open. The exhaust valves are gradually opened by activating the first exhaust valve and then the second exhaust valve. The remaining six exhaust valves are operated simultaneously amd the firing order is activated accordingly.Passive turbochargerExhaust valves with AVS partially ONRecirculation valve openActive turbochargerCompressor sequence valve closed652_061Biturbo modeWhen the system switches over to biturbo mode after the remaining multi-stage exhaust valves open, the recirculation valve is closed and the passive turbocharger is able to build up charge pressure and override the spring-loaded compressor sequence valve. The engine runs in biturbo mode at engine speeds upwards of about 2700 RPM and, with two active exhaust valves, is able to fully utilise the high degree of charging even at high engine speeds. The engine reaches its nominal power output of 320 kW at 3750 RPM and continues to deliver sporty performance up to 5000 RPM. The maximum charge pressure of 3.4 bar is already achieved at 1500 RPM. The maximum engine torque of 900 Nm is available from about 1500 RPM under dynamic full-throttle acceleration. In stationary operation, maximum engine torque is already achieved at 1000 RPM.Exhaust valves with AVS ONPassive turbochargerRecirculation valve closedActive turbochargerCompressor sequence valve open652_038 37 BackForward Ξ ContentsFuel systemSystem overviewThe fuel system is subdivided into 3 pressure areas: High pressures of up to 2500 bar Return flow from the injectors at a pressure of about 14 bar Supply pressure, return pressureReturn flow from the injectorsHigh-pressure connecting lineInjector, cylinder 5 N83 Rail 2Injector, cylinder 6 N84 Fuel metering valve N290 High pressure fuel pumpInjector, cylinder 7 N85Injector, cylinder 8 N86 High-pressure supply line, cylinder bank 2High-pressure sensor G65 Fuel return lineFuel supply line38 BackForward Ξ ContentsFuel pressure control valve N276Solenoid coilInjector, cylinder 1 N30Valve pintleReturn portInjector, cylinder 2 N31Rail 1The fuel pressure control valve is located on the high-pressure accumulator (rail) of cylinder bank 1 and it is used to set the fuel pressure in the high-pressure area. If the fuel pressure in the high-pressure area is too high, the control valve opens a return duct so that a portion of the fuel flows from the high-pressure accumulator into the fuel return line. If the fuel pressure in the high-pressure area is too low, the control valve closes and seals the high-pressure area off from the fuel return line.Injector, cylinder 3 N32Pressure retaining valveReturn flow from the injectors at a pressure of about 14 barInjector, cylinder 4 N33 Spring-loaded ball valveHigh-pressure supply line, cylinder bank 1 To fuel return line at a pressure of about 6 barThe pressure retaining valve is an all-mechanical valve. It is located between the return lines from the injectors and the fuel supply line to the fuel system. The pressure retaining valve maintains a fuel pressure of about 14 bar in the fuel return line from the injectors. This fuel pressure is required for functioning of the injectors.Low-pressure fuel pressure sensor G410 Fuel temperature sensor G81652_087 39 BackForward Ξ ContentsHigh-pressure fuel systemFor the first time at Audi, a common rail system with a maximum injection pressure of 2500 bar is being used as the high-pressure fuel injection system. Rail pressure is produced by two CP4.2 dual-plunger high pressure pumps. Their stroke has been modified from 5.625 mm to 7.5 mm in order to achieve the fuel injection rate needed to deliver peak engine torque. By increasing the fuel injection pressure by up to 500 bar compared to the predecessor engine, it has been possible to design the fuel injectors with only a moderate increase in flow rate at the injector from 400 to 430 ml / 30 s.RailHigh-pressure supply line,Fuel pumpInjector, cylinder 4 N33Fuel return line Fuel supply lineInjector, cylinder 3 N32Fuel metering valve N290 High-pressure supply line, High-pressure sensor G65Injector, cylinder 2 N31Injector, cylinder 1 N30 Injector, cylinder 8 N86 Injector, cylinder 7 N85 Injector, cylinder 6 N84 Injector, cylinder 5 N83Fuel pressure control valve N276High pressure Connecting line652_043High-pressure fuel pump driveTo ensure that fuel delivery is in sync with the injection phase, a pulley to crankshaft ratio of 1 : 1 is employed. To keep chain forces to a minimum, the pump is mounted to the engine in a phaseoriented fashion. This makes it possible to achieve the performance targets for the engine while creating ideal conditions for low-emission combustion in conjunction with the improved combustion process.40 BackForward Ξ ContentsSCR systemReducing agent tank The 24-litre reducing agent tank is manufactured from two halfshells as an injection moulding (not as a blow-moulded tank). This has the advantage of saving weight. This means that allowance can be made in the vehicle design for the integration of baffles and a heating system adapted to the cabin as installation space. Equalisation chamber To be able to hold the reducing agent which flows into the tank at a high rate, there are equalisation chambers in the upper section of the vent line and at the filler neck. Since splashing reducing agent would cause the fuel nozzle to shut off, reducing agent is retained and allowed to settle in the equalisation chamber.Reducing agent filler neck Equalisation chamberReducing agent tank sensor G684 The tank sensor is an entirely electronic component and does not require float contact points. An antenna (coil) and the reducing agent (capacitive fluid) form an electrical resonant circuit. A change in the fluid level alters the impedance of the circuit and shifts the resonance frequency (5 MHz – 12 MHz) proportional to the fluid level.Vent duct Charging portReduction agent tank sensor G684Filling level and fluid level in the SCR tankBaffle Reducing agent tank heater Z102652_059Fluid level [mm]Filling volume [l]Metering system delivery unit for reducing agent GX19Start of range calculationMaximum filling volume652_073Reference For more information about quality analysis of the reducing agent, refer to Self Study Programme 632 "Audi Q7 (type 4M)".41 BackForward Ξ ContentsExhaust systemOverviewExhaust gas temperature sensor 4 (after diesel particulate filter) G648Exhaust gas treatment module Flexible pipeParticulate sensor G784NOx sensor 2 G687Exhaust gas treatment moduleConnecting pipe Exhaust gas temperature sensor 3 after oxidation catalyst G495 NOx accumulator and oxidation catalyst (NOC) with a capacity of 2.37 litres Oxygen sensor G39 Exhaust gas temperature sensor 2 G448NOx sensor G295 Connection to differential pressure sensor G505Exhaust gas temperature sensor 4 (after diesel particulate filter) G648Oxygen sensor after catalytic converter G130652_006Reducing agent injector N474MixerDiesel particulate filter with a copper-zeolyte SCR coating and a capacity of 5.0 litresThe diesel particulate filter has a preciousmetal washcoat at the end of the exhaust gas recirculation system (refer to page 43 for further details of function).42 BackForward Ξ ContentsAmmonia slip catalyst (version for NAR)For the North American Region (NAR), the SCR-coated diesel particulate filter is followed downstream by ammonia slip catalysts, which have a combined SCR and oxidising catalyst coating and perform two tasks: • Task 1: Their first task is to oxidise the carbon monoxide (CO) produced during soot regeneration to carbon dioxide (CO2) by reaction with the coating containing precious metal. • Task 2: The ammonia slip catalysts also ensure that no NH3 (ammonia) leaves the exhaust system under any circumstances. In this process NH3 is oxidised to N2 and H2O .Ammonia slip catalysts652_051Note The tail pipes must not be sealed to carry out leak testing as the backpressure will cause irreparable damage to the speakers.Engine noise generation actuator 2 R258Rear silencer (baffle silencer)Engine noise generation actuator 1 R257652_003 43 BackForward Ξ ContentsEngine managementSystem overviewSensorsAir mass meter G70 Air mass meter 2 G246 Engine speed sensor G28 Intake manifold pressure sensor G71 Intake air temperature sensor G42 Intake air temperature sensor 2 G299 Exhaust turbocharger speed sensor 1 G688 Exhaust turbocharger speed sensor 2 G689 Engine cover temperature sensor G765 Power unit mounting sensor 1 G748 Power unit mounting control unit J931Power unit mounting sensor 2 G749Hall-effect sensor G40 Accelerator pedal position sensor G79 with Accelerator pedal position sensor 2 G185Brake light switch F Combustion chamber pressure sensor for cylinder 2 G6781) Combustion chamber pressure sensor for cylinder 6 G6821) Data bus diagnostic interface J533Fuel pressure sensor G247 Low-pressure system fuel pressure sensor G410Fuel temperature sensor G81Biodiesel concentration sensor G8551)Water level sensor G1201) Engine control unit J623Coolant temperature sensor G62 Coolant temperature sensor 3 G812 Radiator outlet coolant temperature sensor G83 Oil level/temperature sensor G266 NOx sensor 2 G687Oil temperature sensor G8NOx sensor control unit 2 J881Oil pressure sensor G10Exhaust gas recirculation pressure sensor G691 Exhaust gas recirculation potentiometer G212 Exhaust gas temperature sensor 1 - 5 G235, G236, G448, G495, G648 Catalytic converter temperature sensor 1 G201) EGR temperature sensor G98 Differential pressure sensor G505 Oxygen sensor G39 Oxygen sensor downstream of catalytic converter G1301)NOx sensor G295NOx sensor control unit J583Particulate sensor G784Only installed in vehicles for the NAR.44 BackForward Ξ ContentsActuatorsInjector, cylinders 1 – 4 N30 – N33 Injector, cylinders 5 - 8 N83 - N86 Power unit mounting actuator 1 N5131)1)Automatic glow period control unit for J179 Glow plug 1 + 4 Q10, Q13 Glow plug 6 + 7 Q15, Q16 Automatic glow period control unit 2 J703 Glow plug 2 + 3 Q11, Q12 Glow plug 5 + 8 Q14, Q17 Electrical compressor control unit J1123 Charge air recirculation module GX37Power unit mounting actuator 2 N514Throttle valve control unit GX3 Throttle valve control unit 2 GX4 Exhaust turbocharger control unit J724 with V465 Exhaust turbocharger control unit 2 J725 with V546Coolant circuit solenoid valve N492Fuel metering valve N290Fuel pressure control valve N276 Diagnostic portReducing agent injector N474 Intake cam adjuster 1 for cylinders 1 - 8 F448, F452, F456, F460, F464, F468, F472, F476 Exhaust cam adjuster 1 for cylinders 1 - 8 F450, F545, F458, F462, F466, F470, F474, F478 Oil pressure control valve N428Electro-hydraulic engine mounting solenoid valve, left and right N144, N145 Intake manifold control unit GX14 Intake manifold control unit 2 GX15 Exhaust gas recirculation valve GX5 EGR cooling bypass valve N386 EGR cooling bypass valve 2 N387 Electric powered compressor bypass flap valve N731 Electric powered compressor coolant pump V645 Heating assistance pump V488Pressure reducing valve N155 Thermostat for mapped engine cooling F265 Radiator fan control unit J293 Radiator fan V7 Radiator fan control unit 2 J671 Radiator fan 2 V177652_018Oxygen sensor heater Z19 Heater for oxygen sensor 1 downstream of catalytic converter Z2945 BackForward Ξ ContentsServiceSpecial tools and workshop equipmentT40320/3 Assembly tool T40355 Assembly tool652_077652_078For installation of the clutch-side shaft oil sealFor locking the chain tensioner in placeT40356 Locking pinT40359 Counter-hold tool652_079652_080For locking the chain sprocketUsed for counterholding vibration damper when centre bolt for crankshaft is loosened or tightened. This tool is used in combination with T40298.VAS 5161A/37 Guide plateVAS 6095/1-16 BracketV.A.G 1763/11 Adapter652_081652_083652_082For removing and installing the valve cotters.For clamping the engine onto the engine and gearbox bracket VAS 6095For checking the compression above the injector shaft.46 BackForward Ξ ContentsAppendixSelf study programmesFor more information about the 4.0l V8 TDI engine, refer to the following self study programmes.SSP 411 Audi 2.8l and 3.2l FSI engines with Audi valvelift system • Audi valvelift systemSSP 604 The Audi 3.0l V6 TDI biturbo engine • Turbocharging • Sound exhaust systemSSP 622 Second-generation Audi clean diesel • General information about the SCR systemSSP 626 Basics of Audi engine technology ­ • Engine technologySSP 632 Audi Q7 (type 4M) • SCR systemSSP 651 Audi SQ7 (type 4M) • Sound exhaust system • 48-volt electrical subsystem47All rights reserved. Subject to amendment. Copyright AUDI AG I/VK-35 service.training@audi.de AUDI AG D-85045 Ingolstadt Technical revision status 06/16