Tài Liệu Động Cơ Audi 4.0l V8 TFSI (Engine Biturbo Charging)

Brief technical description• Eight cylinder V engine with 90° bank angle • FSI petrol direct injection • Cast aluminium cylinder block • Biturbo charging with twin-scroll exhaust turboch

All rights reserved.

Technical specifi cations are subject to

Self Study Programme 607

For internal use only

Audi has a new addition to its family of V engines The 4.0l V8 TFSI

is the fi rst eight-cylinder petrol engine to feature twin exhaust

turbocharging and FSI technology The engine is based on the

4.2l V8 FSI naturally aspirated engine of the Audi A8 ’12 The basic

engine derives largely from the 4.2l V8 FSI To improve fuel

economy, the displacement was reduced to 4.2 litres from

4.0 litres

Another "active" measure for reducing displacement is "cylinder on

demand" This system allows the engine to operate more effi

-ciently at partial load Another key feature is the HSI (Hot Side

Inside) confi guration For this purpose, both exhaust

turbocharg-ers are integrated in the inside V of the cylinder block Even the

charge air cooler is housed here One of the major development

challenges was fi nding space for the engine in the engine bay

In this Self Study Programme you will learn about the technology

of the 4.0l V8 TFSI engine When you have worked your way

through this Self Study Programme, you will be able to answer the

following questions:

• How is the basic engine designed?

• How do the engine systems (e.g air supply, oil supply, cooling)

gura-this unit in their models

The 4.0l V8 TFSI engine employs all the technologies from Audi’s modular effi ciency platform These range from the start-stop system and the recuperation system to a broad array of friction-reducing measures The V8 is assembled at Audi’s Hungarian plant

in Györ using high-end technologies such as "plate honing"

Reference

The Self Study Programme teaches a basic knowledge of the design and functions of new models, new

auto-motive 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

For further information about maintenance and repair work, always refer to the current technical literature

Introduction

Eight cylinders symbolised by four rings _ 4Brief technical description _ 6Specifi cations 8

Engine mechanicals

Cylinder block 12Cranktrain _16Crankcase ventilation 18Activated charcoal fi lter (ACF) system _23Cylinder heads 24Chain drive 26Auxiliary units drive 27

Oil supply

Overview 28Oil pump 30Oil cooling 33Oil fi lter _34Oil pressure monitoring _36Switchable piston cooling jets 38

Cooling system

System overview _44Engine circuit and cooling module _48Gear oil cooling/heating _50Charge air cooling 53Heating circuit 54Radiator layout _54

Air supply and charging

Overview 56Twin-scroll exhaust turbocharger 58

cylinder on demand

Introduction 62Function _64Active engine mounting system 68Active noise cancelation (ANC) _72

Fuel system

Overview 76

Exhaust system

Overview 78Exhaust valves 80Secondary air system 82

Engine management system

System overview _84MED 17.1.1 engine management system 86

Annex

Service _88Test your knowledge _90Self Study Programmes _91

Contents

Eight cylinders symbolised by four rings

High-performance eight cylinder engines have long been a staple

of Audi's product portfolio They refl ect the brand’s premium

status particularly in the segment of high-performance and sporty

luxury-class saloons However, V8 engines are also available as

options in Audi’s sports cars and SUVs

The origins of eight-cylinder engines bearing the four-rings of the Audi badge go back much further Development of the fi rst eight-cylinder engines began at Horch-Werke, a brand affi liated to Auto Union, which later became Audi AG

The Horch 303 by Horch-Werke of Zwickau was the company’s fi rst luxury-class straight-eight engine Production began in January

1927, and it was the fi rst successful German production car with

an eight-cylinder engine

The straight-eight engine with double overhead camshafts was designed by Paul Daimler, son of Gottfried Daimler Even the most basic version of this model, an open tourer, rated among the top luxury vehicles in Germany An impressive 8490 units of this double-camshaft engine were produced before production ended in 1931

The Horch eight-cylinder was noted for its particularly smooth running Apparently, the engine ran so smoothly, a coin would stay balanced on edge on it while it was running

Continuing the Horch V8 model series, the Horch 830 BL was launched in 1935 on a long- wheelbase chassis In terms of numbers, this was one of the most successful products of the Horch factory Fifty percent of the total of 6,124 units built were Pullman saloons (see illustration)

Introduction

1988 – Entry into the automotive luxury class

2006 – FSI direct injection

2012 – Turbocharging and cylinder on demand

The Audi V8 was presented to the public at the 1988 Paris Motor

Show The vehicle was built at the Neckarsulm plant The V8 was

the only saloon vehicle in the luxury class to be able to boast

permanent four-wheel drive The V8 engine initially had a

displace-ment of 3562 cm³ and developed 185 kW at 5800 rpm It was

followed by a version with a displacement of 4.2 litres, which was

also used in the successor model, the Audi A8

The V8 marked Audi’s entry into the automotive luxury class

Production of the Audi A8 ended after six years early in the

summer of 1994 In the early 1990's, Audi made a successful foray

into the German Touring Car Championship with its V8, winning

two championship titles

For more information, please refer to Self Study Programme 106

"Audi V8" and Self Study Programme 217 "The V8 5V engine"

To utilise the potential of direct fuel injection for its V8 engines,

Audi equipped the 4.2l V8 engine with FSI petrol direct injection

The engine was available in two versions - a comfort-oriented basic

version (used for the fi rst time in the Audi Q7) and a sporty

high-revving version for the Audi RS4 ’06 (309 kW at 7800 rpm)

The V8 was reconfi gured for use on the Audi Q7 (257 kW at

6800 rpm) Characteristics of this new engine included a fuller

torque curve up to maximum rated speed and immediate throttle

response The engine excelled not only with its dominant power

output and high torque The resultant driving performance was

excellent, and stood up well against the tough competition

For further information, please refer to Self Study Programme 377

"Audi 4.2-litre V8 FSI engine"

The 4.0l V8 TFSI is the fi rst Audi eight-cylinder petrol engine to

feature twin exhaust turbocharging and FSI technology There are

multiple versions of this engine, which are used in various models

of the Audi C and D series

The main focus of development was on reducing fuel consumption

- and this was achieved by a number of measures, such as cylinder

Brief technical description

• Eight cylinder V engine with 90° bank angle

• FSI petrol direct injection

• Cast aluminium cylinder block

• Biturbo charging with twin-scroll exhaust turbochargers in the

inside V of the cylinder block

• Double air gap insulated exhaust manifold

• Indirect charge air cooling

• Cylinder management/cylinder on demand (COD)

• 2nd generation thermal management system (ITM 2)

• Crossfl ow cooling

• MED 17 1.1 engine management system with p-N control

• Recuperation system for energy recovery under braking

• Start-stop system (model and country dependent, see table on page 7)

• Active engine mounting system with oscillating coil actuators

607_013 Engine on the Audi S7 Sportback, viewed from the rear

! Note

The technical descriptions given in this self study programme are based on the engine type of the Audi S6 ’12 and

Audi S7 Sportback (C7 series) Diff erences between this engine and other engine versions are highlighted in the descriptions

of the individual modules

Versions

The 4.0l V8 TFSI engine is used on various Audi models Depending

on model series and the markets in which vehicles are available,

the engines used have diff erent characteristics

Model Audi S6 ’12

Audi S7 Sportback

Audi A8 ’12 Audi S8 ’12

Power output in kW (HP) 309 (420) 309 (420) 382 (520)

Markets without

recupera-tion system and start-stop

system

Asia, USA, Canada, Korea, SAM3) Asia, SAM3) Asia, USA, Canada, Korea

Exhaust emission

The following table provides an overview of the versions and types

or adaptations You will fi nd further specifi cations on the following pages

1) The illustration shows the engine on the Audi S6 ’12

2) The illustration shows the engine on the Audi S8 ’12

3) SAM = South American Market

• One-sided air intake for both turbochargers

• No power steering pump

• Engine cover design

Audi S6 ’12, S7 Sportback (C7 series)

607_014 Front view of engine in Audi S7 Sportback with air intake

Engine speed [rpm]

Torque/power curves

Engine management Bosch MED 17 1.1 with p-N control

Exhaust emission standards EU 2 ddk, ULEV 2, Tier 2 BR, EU 5, EU 5 plus

The 4.0l V8 TFSI engine is used in the D4 series in two power

ratings

Key distinguishing features between the engines in the C7 series

are:

• Double-sided air intake (in the Audi S8 ’12 only)

• Additional power steering pump

Audi A8 ’12, Audi S8 ’12 (D4 series)

607_007 Front view of engine in Audi S8 ’12 with air intake

• Engine cover design

• The secondary air pump motor has a diff erent installation position (on the right-hand side of the engine compartment)

607_004 607_003

Type Eight cylinder V engine with 90° bank angle Eight cylinder V engine with 90° bank angle

Engine management Bosch MED 17 1.1 with p-N control Bosch MED 17 1.1 with p-N control

Fuel Premium unleaded (sulphur-free) 95 RON Premium unleaded (sulphur-free) 98 RON

Exhaust emission standards EU 2 ddk, ULEV 2, Tier 2 BR, EU 5, EU 5 plus ULEV 2, Tier 2 BR, EU 5 plus

Cylinder block

The crankcase derives from the 4.2l V8 FSI engine of the Audi

A8 ’12 It is manufactured by low pressure chill casting from a

hypereutectic Alusil alloy

The mechanical and thermal loads are higher than those of the

4.2l V8 FSI engine To withstand these higher loads, a special heat

treatment is used However, heat treatment varies depending on

engine version (there are various degrees of charging) The cylinder

liners are mechanically stripped and their surfaces textured by

plate honing

Switchable piston cooling jets designed to cool the pistons by

means of oil spray are integrated in the cylinder block (see

„Swit-chable piston cooling jets“ on page 38)

Cylinder block dimensions Cylinder spacing in mm 90

Oil pan top section

Oil pan bottom section

Wind- age tray

607_024

Switchable piston cooling jet

Engine mechanicals

Bed plate

The bed plate is a high pressure die casting made of aluminium

alloy The task of the bed plate is to provide a base for the

crank-case and to absorb the loads exerted on the crankcrank-case bearings It

makes a signifi cant contribution to improving overall strength and

engine acoustics

Five cast-in-place inserts (crankshaft bearing caps) made of

nodular graphite cast iron are used to strengthen the bearing

support In addition, they are bolted to the bed plate at an angle

607_025

The bed plate is sealed off from the oil pan top section using liquid sealant Cast-in-place inserts

Elastomer cylinder block seals

Screw connection of cast insert at

an angle of 45° (on both sides)

Oil module in inside V

There are numerous oil supply ports under the cover in the inside V

of the engine block The cover is bolted directly to the cylinder

block, with a metal gasket sandwiched in between

607_026

Windage tray

The windage tray closes off the cranktrain from the oil pan The

throws of the crankshaft do not immerse directly into the engine

oil This prevents foaming of the engine oil at high engine speeds

To reduce the weight of the engine, the windage tray is made of

plastic

607_027

Windage tray

Return line to oil pan

Piston cooling jet switching valve

Piston cooling jet control valve

N522

Oil pressure switch, stage 3 F447

Cover of oil module in inside V

Oil return line from fi ne oil

sepa-rator of crankcase breather

Mesh fi lter in turbocharger oil

feed

Oil return line from oil

separa-tor of crankcase breather

Turbocharger oil feed Turbocharger oil return line

Oil return line from coarse oil separator of crankcase breather Turbocharger oil return line

Oil module in inside V

Crankcase breather

Non-return valve for

turbocharger oil supply

Direction of travel Metal bead gasket

Sealing screw

Oil pan top section

The oil pan top section is an integral part of the engine-gearbox

unit and contributes to the overall strength of the assembly In

non-pressurised spaces, the oil pan top section is sealed off from

the bed plate and the oil pan bottom section using liquid sealant

The pressurised spaces have elastomer seals

All oil ducts which transfer contaminated oil from the bed plate

and clean oil to the bed plate are an integral part of the oil pan top

• Additional oil cooler thermostat1) (air-oil)

• Coolant pump mounting

• Dip stick mountings

• Alternator support bracket

• Oil return lines from turbochargers and cylinder heads

• Oil return shut-off values of the crankcase ventilation system

Oil pan bottom section

The oil pan top section is sealed at the bottom by a bolted-on oil

pan bottom section made from sheet aluminium The oil drain

screw as well as the oil level and oil temperature sensor G266 are

integrated in the oil pan bottom section

607_028

1) In Audi S8 ’12 only

Additional oil cooler thermostat 1) (air-oil)

Oil cooler

Oil pan top section

Oil pan bottom

Oil return line shut-off

valve

Oil return line shut-off valve

Crankshaft with diff erent main bearing diameters, depending on engine version

Cranktrain

Overview

607_020

Piston

Cast pistons with a cast-in ring land for the compression ring are

used in all engine versions In the case of the pistons, too, a

dis-tinction is made between the 309 kW version and the

higher-output engine versions

The main diff erence is the shape of the piston crown, as illustrated below The gudgeon pins have a fi ne, diamond-like carbon coating with the designation DLC (Diamond Like Carbon)

Engine version developing 309 kW Engine versions developing 382 kW or higher

Piston with diff erent main shape, depending on engine version Trapezoidal conrod (cracked)

Conrod

The conrods of all power output versions are designed as cracked

conrods The upper conrod eye has a trapezoid angle of 13° The

gudgeon pin has a diameter of 22 mm The conrod bush is made of

bronze

Crankshaft dimensions

Crank pin diameter in mm 90

Main bearing diameter in mm 65 (309 kW)

67 (from 382 kW)

Crankshaft

The forged steel crankshaft runs on fi ve bearings Blanks made of

diff erent materials are used, depending on engine version

Depending on the engine power rating, however, the fi nished part

is fi nish-machined diff erently

Bearings and oil supply

Lead-free three-material composite bearings are used as main bearings Oil is supplied via two through-holes per bearing (cres-cent-shaped slot in cylinder block) Diff erent bearing materials are used for the conrod bearings The lower bearing shell is, like the main bearing, designed as a lead-free three-maerial bearing Lead-free two-material bearings are used as the upper bearing shell

Note: A repair kit with oversize conrod bearings is available as a repair solution (see Electronic Parts Catalogue (ETKA))

607_010

Crescent-shaped slot for

supplying the main

bear-ings with two

through-holes in the upper bearing

The visco damper reduces rotary vibration produced by gas and

mass forces in the internal combustion engine (intra-engine

combustion, rotating and oscillating masses) The vibrations result

in relative movement between the housing and fl ywheel ring

As a result, the silicone oil is subjected to shear load These stresses act on the entire surface of the gap between the fl ywheel ring and the housing The overall load is the resultant damping

eff ect

Housing

Bearing elements Flywheel ring

Silicone oil

Cover

Vibration damper

Crankcase ventilation

The crankcase is ventilated via both cylinder heads The blow-by

gases are channelled into the crankcase ventilation module

through separate ports, which are routed to the intake manifolds

and then to the charge air ducting module

The crankcase ventilation module is located in the inside V of the engine and performs several tasks:

• Coarse oil separation

• Fine oil separation

• Pressure control via the pressure control valve

• Positive crankcase ventilation (PCV)

607_058

Note

A leaky oil return line from the coarse oil separator can result in increased engine oil consumption or blue smoke in the exhaust The oil return line shut-off valves are integrated in the oil pan upper section They cannot be replaced separately

Flow of blow-by gases inside the air manifold housing

Intake of blow-by gases into

the intake manifold

Oil return duct from the coarse oil separator

Oil return line shut-off valve for the coarse oil separator

Oil return duct from the fi ne oil separator

Overview

Positive crankcase ventilation module

Intake of blow-by gases into the intake

manifold (at full throttle)

Charge air cooling module

Coarse oil separation

In the fi rst, high-volume chamber, the blow-by gas fl ow changes

direction by approx 180° The larger oil droplets bounce off the

walls because they have more inertia and fl ow into the collecting

chamber at the bottom of the coarse oil separator Here, there is a

drainage outlet which is connected to the cover of the oil module

in the inside V

The outgoing oil fl ows back into the oil pan through an oil return duct below the oil level in the cylinder block An oil return shut-off valve closes automatically when the engine is running, due to pressure diff erential in the crankcase and oil mist separator This prevents untreated blow-by gases from bypassing the fi ne oil mist separator

607_059

Oil return line shut-off valves

Two oil return line shut-off valves are built into the oil return ducts

They prevent the intake of untreated blow-by gases from the

crankcase The valves in question are spring-loaded ball valves

They are clipped into the top section of the oil pan

607_120

Oil return into the oil pan

Oil return from the coarse

or fi ne oil separator

Cover of oil module in inside V

Oil return duct from the

coarse oil separator into

the oil pan

Larger oil droplets are separated by

changing the direction of the

blow-by gas fl ow

Coarse oil separator

Oil return line shut-off valve for

the fi ne oil separator

Fine oil separation

The blow-by gas fl ows out of the coarse oil separator, through the

fi ne oil separator and into the second chamber The impactor, the

pressure control valve, the blow-by valves and the PCV valve are all

located here Initially, the blow-by gas is treated in the fi ne oil

separator

This works on the same principle as an impactor It also uses a

pressure limiting valve, which opens at high blow-by volumetric

fl ow rates and thus limits pressure loss throughout the entire

system

Like the coarse oil, the separated fi ne oil is returned to the oil pan through a separate connection in the inside V of the engine block

A non-return valve is also fi tted here

A treated blow-by gas fl ows through the single-stage pressure control valve Depending on the pressure conditions in the air supply system, the blow-by gas is admitted to the combustion chamber through the blow-by valves integrated in the air charging module or positive crankcase ventilation module

607_060

Intake of blow-by gases

Admission of separated oil into the oil module in the inside V

Oil return duct into the oil pan

Pressure control valve

Cover oil oil module

in inside V

Coarse oil

separa-tor

Overview

Fine oil separation via an

impactor with fl utter valve

Impactor with fl utter valve

Reference

For more information on the design and functional principle of an impactor, please refer to Self Study Programme 490

"Audi 6.3l W12 FSI engine"

Infl ow of treated blow-by gases

Idle and partial-throttle operation

Vacuum is present in the air supply at idle and at partial load The

treated blow-by gases are admitted into the charge air cooling

module In the process, the blow-by valve for idle and partial load

is opened by the suction eff ect

Full throttle operation

If vacuum is present in the charge air line when the engine is in

charging mode, the blow-by valve in the charge air module which is

operating at partial load closes The treated blow-by gas is now

admitted upstream of the turbocharger by the blow-by valve

integrated in the positive crankcase ventilation module

blow-by gases

Pressure control valve

Positive crankcase ventilation module

Charge air cooling Charge air cooling

Treated blow-by gases from the coarse and fi ne oil separators

Blow-by valve (closed)

Admission of blow-by gases

at idle and at partial load

Blow-by valve (open)

Positive crankcase ventilation (PCV)

Fresh air is admitted into the crankcase via the positive crankcase

ventilation module The crankcase is ventilated at idle and at

partial load only The fresh air fl ows into the positive crankcase

ventilation module through the "full throttle" blow-by connection

A defi ned amount of fresh air is admitted into the crankcase via a connection on the cover of the inside V via a plate valve and a bore

in the positive crankcase ventilation module If the engine is in charging mode, the plate valve closes due to pressure diff erences

Air routing

Blow-by connection

"full throttle"

Blow-by valve (closed) Plate valve 2

Activated charcoal fi lter (ACF) system

The ACF system has been adapted to the new system conditions

This applies in particular to the admission of fuel vapours for

combustion In previous systems with charged petrol engines, fuel

vapours were admitted at two points Firstly, fuel vapours were

admitted downstream of the throttle valve at idle and at low

partial load due to the vacuum present in the air intake Secondly,

fuel vapours were admitted upstream of the turbine during the

phase in which charge pressure is present in the system Fuel

vapour admission was controlled by a mechanical valve system

The engine management system of the 4.0l V8 TFSI engine is confi gured such that the air supply is largely unrestricted at full throttle As a result of this, the pressure diff erential is too small

to fl ush the ACF canister

For this reason, the ACF system is designed in such a way that the fuel vapours are admitted at idle and at low partial load only For this purpose, the activated charcoal canister solenoid valve N80 is activated on the basis of a characteristic map

Activation of the intake manifold valves

The intake manifold valves are integrated in the intake manifolds

(see Fig.607_051 on page 56) When actuated, they shut off the

lower air duct in the cylinder head The induces a tumbling type of

movement in the air fl owing into the combustion chambers The

ports in the cylinder head are separated by dividers All intake

manifold valves in a cylinder bank are mounted on a common

shaft

The shaft is driven by a spring-loaded vacuum cell Both intake

manifold valve vacuum cells are commonly actuated by the intake

manifold valve valve N316 N316 is positioned in the area of

cylinder 4 on the intake manifold adjacent to theintake manifold

valve potentiometer G336 (see Fig 607_121)

A vacuum line is routed around the engine in order to supply the vacuum cell on cylinder bank 2 with vacuum from N316 The engine control unit receives feedback on the position of the intake

fl aps from intake manifold potentiometers G336 and G512

Both potentiometers are positioned opposite the vacuum cell This allows the shafts to be tested for proper functioning

Intake manifold valve valve N316

Intake manifold valve vacuum cell

Intake manifold valve vacuum cell

Cylinder heads

The cylinder heads of the 4.0l V8 TFSI engine have been

rede-signed The challenge facing the engineers was to meet the higher

mechanical and thermal demands compared to the cylinder heads

of the 4.0l V8 FSI engines

The cylinder heads of all power output versions of the engine are

identical in terms of their design The only distinction is that the

engine versions with power outputs of higher than 309 kW have

diff erent camshaft timings (camshaft event durations)

The key diff erence is the reverse layout of the intake and exhaust

ends (Hot Side Inside – HSI) This layout makes for compact

design, improved thermodynamics and short gas fl ow paths with a

minimum of fl ow losses

The 4.0l V8 TFSI engine responds crisply to accelerator pedal inputs A sophisticated system of insulating hot components, particularly the manifold, ensures that thermal conditions in the inside V are stable

The fresh air intake system is located on the outside of the cylinder banks

Switchable fl aps in the intake ducts induce a tumbling type of movement in the incoming air This swirling fuel-air mixture cools the combustion chambers, allowing a high compression ratio to be achieved during charging without causing combustion knock

Technical features

• Aluminium cylinder head with twin composite camshafts

• Four valves per cylinder

• Cylinder head covers with ladder frame

• Variable intake and exhaust valve timing

• Pulse sender (Hall sensors) for camshaft position monitoring

• Crossfl ow cooling

• Cooled intake and exhaust valve bridge

• cylinder on demand via AVS, see page 60

• Three-layer cylinder head gasket

• The cylinder head gaskets are sealed with liquid sealant

• Intake ports with divider

• Central layout of the spark plugs (in the centre of the valve stem)

• Lateral layout of the injectors

• The high-pressure fuel pumps are driven by the exhaust shafts (triple lobe cam)

cam-• The mechanical vacuum pump is driven by the intake camshaft

The valves are actuated by roller cam followers They have a diff

er-ent geometry to allow for cylinder on demand The roller cam

followers with wide rollers are assigned to the cylinders without

cylinder on demand The roller cam followers with narrow rollers

are assigned to the cylinders with cylinder on demand Other

features:

• Static hydraulic valve lash adjustment

• Sodium-fi lled exhaust valves with reinforced seats for cooling

• Solid-stem intake valves with reinforced seats

• Sintered lead steel exhaust valve guides

• Brass intake valve guides

• Simple valve springs with relatively low tension

• Valve lift: 11 mm

Variable valve timing

The intake and exhaust valve timings are continuously variable Each of the valves has an adjustment range of 42° crank angle The position of the camshaft is monitored by a Hall sender After shutting off the engine (the oil pressure drops), the camshaft adjusters are locked by a spring-loaded locking pin

The variable valve timing (VVT) allows the internal recirculation of exhaust gases by means of valve overlap Exhaust gases are recir-culated both in 8 cylinder mode and in 4 cylinder mode

Legend of fi gure on page 25:

1 VVT actuators

2 Hall sender G40

3 High-pressure fuel pump

4 Intake camshaft timing adjustment valve N205

5 Exhaust camshaft timing adjustment valve 1 N318

6 Hall sender 2 G163

7 Cylinder head cover

8 Intake camshaft

9 Movable cam member

10 Roller cam follower with support element

11 Valve spring retainer

12 Valve stem seal

13 Valve cotters

14 Valve spring

15 Intake manifold

16 Non-return valve with vacuum pump connection

17 Intake manifold valve potentiometer G336

18 Port dividers in cylinder head

16 15

11 9

12 13

607_029

Direction of travel

Chain drive

The engine is controlled by a chain drive with four chains in a

biplanar confi guration The chain drive is located on the power

output side of the engine Hydraulic tensioners with a non-return

valve are used as a tensioning system All chain drives use roller

chains Chain drive A distributes power from the crankshaft to the

as a spur gear drive

The valve timing is set and checked using the new locking tool T40264/1-3 The cylinder head covers do not have to be removed

in order to lock the camshafts

Auxiliary drive gear module

Chain drive D drives a gear module, which in turn drives nearly all auxiliary units (see „Other auxiliary units“ on page 27)

The alternator is the only exception („Alternator“ on page 27)

Chain drive B

Chain drive A

Chain drive C

Chain drive D Spur gear drive

Auxiliary units drive

Alternator

The alternator is driven by a fi ve-rib poly-V belt An automatic belt

tensioner with a damping function provides the correct amount of

pre-tensioning

Other auxiliary units

The other auxiliary units are driven by the crankshaft through chain

drive D, a spur gear drive, a gear module and splines

607_009

Power steering pump

The power steering pump on the Audi A8 ’12 is driven by the

engine The power steering pump is driven by the crankshaft

through chain drive D, a spur gear drive and a gear module

C7 series vehicles no longer have a power steering pump drive

An electro-mechanical steering system is used here (see SSP 480)

pump

A/C compressor

Oil fi lter

Oil module in inside V

Cylinder bank 1

Main oil gallery

Engine oil cooler supply

from cooling circuit

Engine oil cooler return

to cooling circuit

Oil ports for supplying the camshafts and the

support elements on the roller cam followers

Riser line to main oil gallery

The 4.0l V8 TFSI engine has a wet sump lubrication system

For the fi rst time, activatable piston cooling jets are used in an

8-cylinder petrol engine

Oil supply

Cylinder bank 2

Turbocharger oil supply

Camshaft adjuster

Switchable piston cooling jets

Oil pump with intake from oil pan Chain tensioner

Oil pump

The 4.0l V8 TFSI engine has a regulable oil pump, which is

designed in such a way that it can operate in two pressure stages

In addition, engine oil demand is continuously adapted by

regulat-ing the volumetric fl ow of the pump (in both pressure stages) Use

of this pump has improved fuel economy For this purpose, the

pump is operated in the lower pressure stage at low engine speeds

(low drive output)

The low pressure level is at a relative pressure of approx 2 bar The

high pressure level is at approx 4.5 bar The pressure relief valve in

the pump opens at approx 11 bar (cold start valve)

The oil pump is bolted to the bed plate It is driven by the spur

gear drive (chain drive D) via a spline The spur gear drive of the oil

pump also drives the engine coolant pump (see fi g on page 26)

Design

In design terms, the pump is a vane cell pump with an excentrically

mounted adjusting ring which is an integral part of the pump

interior Rotating the adjusting ring changes the volume of the

pump interior and hence the delivery rate or, after change-over, the

pressure inside the system

A specially shaped intake manifold with mesh fi lter and rubber

base ensures that engine oil is taken in safely from the oil pan and

in a manner favourable to fl ow in the pump, even under high

transverse vehicle acceleration

Adjustment device

The adjustment ring rotates when oil pressure acts on the control faces, whereby the infl ow to control face 2 can be controlled by the oil pressure control valve The counterforce is generated by two control springs They push against control face 2 of the adjusting ring The springs have special characteristic curves This ensures that the fl ow rate is always correct in both the low and high pres-sure stages

607_031

607_032

Oil pump in oil pan top section

Ball valve Adjustment ring

Vane cells

Drive shaft Oil pump cover

Intake manifold with mesh fi lter

Control springs

Oil pump housing

Drive spline

Schematic diagram of the oil pressure control system

607_030

Volumetric fl ow control function (identical for both pressure stages)

Increased delivery rate

At rising engine speed, a pressure drop occurs within the system

due to the increased oil requirements of systems As a result, the

control springs displace the adjusting ring in such a way as to

enlarge the space inside the pump, thereby increasing the delivery

rate of the pump

Reduced delivery rate

At decreasing engine speed, the engine requires less oil and the pressure increases The higher pressure acts on the control face(s)

of the adjusting ring and displaces the ring in such a way that the space inside the pump decreases, thereby reducing the delivery rate of the pump

G Air-oil heat exchanger1)

N428 Oil pressure control valve

1) Only in engine versions with power outputs of higher than 309 kW

(control face 1)

Pressure control A

(control face 2)

Volumetric fl ow control

Oil pressure regulation function

Low pressure level

The oil pressure regulation valve N428 is actuated by the engine

control unit, thereby opening the port to control face 2 The oil

pressure generated by the pump now acts on both control faces

and increases the rotation of the adjusting ring

The pump space decreases in size, with the result that less oil is

conveyed The oil pressure drops The oil pump runs at a lower

drive output, providing better fuel effi ciency

High pressure level

The high pressure stage is selected at an engine speed of

4000 rpm The oil pressure regulation valve N428 is deactivated

for this purpose

The oil fl ow to control face 2 of the adjusting ring is interrupted as

a result The control springs now push back the adjusting ring,

thereby decreasing the space inside the pump The delivery rate of

the pump increases and the oil pressure is adjusted to the high

pressure level The oil pushed back by control face 2 is diverted

into the oil pan via N428 (see Fig 607_030 on page 31)

The lower pressure level is selected when the engine speed drops

Oil cooling

The oil conveyed by the oil pump is initially admitted to

an oil ducting system in the top section of the oil pan To this end,

it must pass a non-return valve This ensures that the oil circuit

does not run dry

The oil then fl ows through the oil cooler, which is designed as a

water-oil cooler and thus is integrated in the engine cooling circuit

(see „Cooling system“ on page 44)

Additional oil cooler

An additional oil cooler is available for the engine version in the

Audi S8 ’12 It is an air-oil cooler and is cooled by the airstream at

the front end of the vehicle Unlike the oil cooler, oil does not

continuously fl ow through this cooler Oil fl ow through the

addi-tional oil cooler is enabled by a thermostat (see „Schematic

diagram of the oil pressure control system“ on page 31)

The water-oil cooler is bolted to the top section of the oil pan below the vibration damper The oil from the oil cooler fl ows back into the oil ports of the oil pan top section, and from there to the bed plate

An additional bypass valve is fi tted in order to protect the oil cooler It opens at a pressure of 2.5 bar (relative) and diverts oil into the oil cooler return line

The thermostat is located in the oil port of the oil pan top section and opens at an oil temperature of 110 °C The additional oil cooler vents itself automatically The additional oil cooler does not run dry when changing the engine oil

607_042

Coolant return line

Coolant feed Oil cooler (coolant-oil)

Oil cooler feed line

Oil cooler return line Bypass valve

Note

The additional oil cooler thermostat cannot be replaced separately The oil pan top section must be replaced, if necessary

Oil fi lter

The oil coming from the oil pan top section (oil cooler) fl ows into

the cylinder block, where the mounting for the oil fi lter is located

The oil fi lter consists of a polymer fi lter cartridge and is supported

by a plastic cap The plastic cap is bolted to the bed plate when

replacing the fi lter

The fi lter is mounted in suspension in an easy-to-service position in

the engine To simplify oil fi lter replacement, there is a drain screw

on the plastic cap

Oil pressure switches F22 and F378

Above the oil fi lter there are two oil pressure switches which

monitor both pressure stages (see „Oil pressure monitoring“ on

page 36)

A third oil pressure switch is used for monitoring the oil pressure

for the piston cooling jets (see „Oil pressure switch, stage 3 F447“

on page 42)

607_043

607_044

Oil pressure switch F22

Oil pressure switch for reduced oil pressure F378

Oil consumers

The treated oil fl ows from the oil fi lter into the main oil gallery

From here, all oil consumers are supplied with engine oil:

• Crankshaft

• Piston cooling jets (switchable)

• Chain drive (chain tensioner)

• Cylinder heads (valvegear, variable valve timing)

• Oil pump (oil pressure regulation)

• Exhaust turbocharger

• Vacuum pump

607_045

607_046

The oil temperature is measured en route to the main oil gallery

For this purpose, oil temperature sensor 2 G664 (NTC) is bolted

into the riser line

If the engine oil temperature exceeds 125 °C, engine power output

is reduced by the engine control unit This serves to protect the

lead-free bearing shells in the cranktrain (see „Cranktrain“ on

page 16)

Engine power output is also reduced if the engine control unit

receives an implausible signal or no signal from the sensor

A diagnostic trouble code is stored in the engine control unit

A fault indicator lamp is not activated

Additional oil temperature measurement

Oil temperature sender 2 G664 Riser line to main oil gallery

Main oil gallery

Oil fi lter

Oil pressure monitoring

607_038

Basically, the oil pressure is monitored by two oil pressure

switches This is necessary, because two oil pressures are produced

4 Signal from oil pressure switch F22

5 Signal from oil pressure switch fo rreduced oil pressure

F378

F22 Oil pressure switch F378 Oil pressure switch for reduced oil pressure J285 Control unit in instrument cluster

J533 Data bus diagnostic interface J623 Engine control unit

Function and signals of the oil pressure switches

The two oil pressure switches are used for monitoring the oil

pressure The oil pressure switch for reduced oil pressure F378

checks for the presence of oil pressure

Oil pressure switch F22 monitors the high pressure level of the regulated oil pump if the latter is operating in the high pressure stage

Signals from the oil pressure switches

The oil pressure switch is evaluated in the engine control unit J623

(in previous concepts involving the use of a single-stage oil pump,

the oil pressure switch was read in and evaluated by the control

unit in the instrument cluster J285)

The oil pressure switches are NO contacts which connect to ground

as soon as the required oil pressure is present Both oil pressure switches are connected directly to the engine control unit J623

Oil pressure monitoring process

The oil pressure switches are monitored in the engine control unit

at engine ON and checked for plausibility at engine OFF

Plausibility check at engine OFF

When the engine is turned OFF, no signal from a connected oil

pressure switch may be present Otherwise, an electrical fault

must be assumed

Warning at engine ON

Depending on the oil temperature, the oil pressure switches are

monitored upwards of a defi ned engine speed threshold

Oil pressure switch F378 (low pressure stage):

The oil pressure switch is generally monitored when the engine is

cold (up to 60 °C), i.e at idle When the engine is at operating

temperature, the oil pressure switch is not monitored until high

engine speeds are reached If the switch is not closed, the "red oil

can" warning is displayed in the instrument cluster together with

the fault text "Switch off engine and check coolant level"

Oil pressure switch F22 (high pressure stage):

The oil pressure switch F22 is monitored as soon as the regulated oil pump is operating in the high pressure stage and the engine speed exceeds a value computed in the characteristic map (this is dependent on the oil temperature) If it is determined that the switch is not closed, the engine electronics warning lamp K149 is activated In addition, the engine speed is limited

The limited engine speed is indicated by a text message in the instrument cluster and by a yellow speed symbol

Fault analysis options

Diagnostics can be carried out in the engine control unit using the

oil pressure monitoring function

607_039

At terminal 15 ON, a warning is displayed in the instrument cluster ("red oil can" together with fault text "Switch off engine and check coolant level")

Switch off engine and check coolant level

D8

Switchable piston cooling jets

In principle, it is not necessary to cool the piston crowns with oil

spray in every engine operating situation If the piston cooling jets

are deactivated, the oil pump has less oil to convey (volumetric

fl ow control), which, in turn, saves a small amount of fuel

The piston cooling jets are activated and deactivated by the piston cooling jet control valve N522 This valve is located in the inside V

of the cylinder block A switching valve which controls the oil fl ow

to the piston cooling jets is actuated hydraulically by N522

607_047

Switching valve, self-opening (spring force)

Piston cooling jet control valve N522

Oil pressure switch, stage 3 F447

Cover of oil module in inside V

Oil intake from the oil pump

Main oil gallery

Switchable piston cooling jet

Overview of system components

Central oil distributor rail for all piston cooling jets

Piston cooling jets activated

If the piston cooling jet control valve N522 is not activated by the

engine control unit, the port to the piston cooling jets is open The

piston crowns are sprayed with oil spray

This ensures that the piston crowns are cooled in the event of the

following faults:

• Faulty cable, loose connector, sticking electrical control valve

• Sticking hydraulic switching valve

• Faulty activation

607_015

Piston cooling jet control valve N522

− not activated

Switching valve, self-opening (spring force)

− opens at approx 0.9 bar

Main oil gallery

Oil intake from the oil pump

Piston cooling jets spray the oil onto the piston crowns

Unpressurised

System pressure

Oil pressure switch,

stage 3 F447

Piston cooling jets deactivated

The deactivation of the piston cooling jets is controlled A

charac-teristic map is stored in the engine control unit for this purpose

(see fi gure on page 43) The piston cooling jets can only be

switched off when current is present Port A is opened when the

piston cooling jet control valve N522 is activated

Piston cooling jet control valve N522

− activated

Switching valve, closed (spring force)

Main oil gallery

Oil intake from the oil pump

Piston cooling jets do not spray any oil onto the piston crowns

Oil pressure switch,

stage 3 F447 – not switched