920143

eSelf Study Program 920143
The Audi 2.0L Third Generation TDI Engine
2
Audi of America, LLC
Service Training
Created in the U.S.A.
Created 4/2014
Course Number 920143
©2014 Audi of America, LLC
All rights reserved. Information contained in this manual is based on
the latest information available at the time of printing and is subject to
the copyright and other intellectual property rights of Audi of America,
LLC., its affiliated companies and its licensors. All rights are reserved
to make changes at any time without notice. No part of this document
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be referred to Audi of America, LLC.
Always check Technical Bulletins and the latest electronic service repair
literature for information that may supersede any information included
in this booklet.
This eSSP contains video links which you
can use to access interactive media.
Note
This eSelf Study Program provides a basic knowledge of the design and functions of new models,
new automotive components or technologies.
It is not a Repair Manual! All values given are intended as a guideline only.
For maintenance and repair work, always refer to the current technical literature.
Revision 1: 5/2014
3
Reference
Contents
Introduction......................................................................................6
Brief technical description ................................................................................................................................... 7
Specifications of 2.0l TDI engine ......................................................................................................................... 9
Engine mechanicals...........................................................................10
Cylinder block ........................................................................................................................................................
Crankshaft assembly ............................................................................................................................................
Balancer shafts .....................................................................................................................................................
Toothed belt drive .................................................................................................................................................
Auxiliary component drive ...................................................................................................................................
Cylinder Head.........................................................................................................................................................
Layout of the valves ..............................................................................................................................................
Cylinder head coolant jacket ................................................................................................................................
10
11
12
13
14
15
16
17
Variable camshaft timing..................................................................19
Introduction .......................................................................................................................................................... 19
Operating ranges .................................................................................................................................................. 21
Positive crankcase ventilation............................................................22
Oil supply...........................................................................................23
Oil circuit ............................................................................................................................................................... 23
Oil pump with integral vacuum pump ................................................................................................................ 24
Oil filter module .................................................................................................................................................... 28
Cooling system..................................................................................30
Thermal management .........................................................................................................................................
Switchable coolant pump ....................................................................................................................................
System overview ...................................................................................................................................................
Coolant thermostat ..............................................................................................................................................
Coolant expansion tank with silicate repository ................................................................................................
30
30
32
37
38
Fuel System.......................................................................................39
Fuel injectors .........................................................................................................................................................
Injector in rest position ........................................................................................................................................
Start of injection ...................................................................................................................................................
Pre-heating the fuel filter ....................................................................................................................................
Pulsation damper .................................................................................................................................................
40
41
42
43
44
Engine management system.............................................................45
System overview ...................................................................................................................................................
Glow plug system .................................................................................................................................................
Function .................................................................................................................................................................
Air regulation overview ........................................................................................................................................
Charge pressure control .......................................................................................................................................
Charge air cooler ...................................................................................................................................................
45
47
48
49
51
53
Exhaust system.................................................................................55
Longitudinally mounted engines ......................................................................................................................... 55
Transversely mounted engines ............................................................................................................................ 55
Exhaust gas treatment......................................................................57
Exhaust emission standards ................................................................................................................................ 57
Exhaust Door Control Unit J883 .......................................................................................................................... 62
SCR-System ........................................................................................................................................................... 64
Special tools and workshop equipment.............................................67
Knowledge Assessment....................................................................69
4
608_001
5
Introduction
A new family of diesel engines has been developed with the
designation EA288. EA is for Entwicklungsauftrag which
means “development order.” It is based on the existing
EA189 engine family.
Audi engineers have translated this development to the
Modular Diesel Platform (MDP) so successive platforms in
the mid-range, compact and subcompact classes can be
supplied with identical or adapted engine modules.
The modular design principle has been applied both to the
core assemblies (basic engine assembly, cylinder head and
valve train) and to the ancillary components (close-coupled
exhaust gas treatment system and intake manifold with
integrated charge air cooler). Numerous sub-assemblies
have already been redesigned and re-developed for the new
4-cylinder diesel engines in the EA288 family.
1
4
2
5
3
6
7
8
9
10
514_104a
Core assemblies
Ancillary components
1 Camshaft housing
7 Exhaust manifold module with turbocharger
2 Cylinder head
8 Intake manifold with water-cooled charge air cooler
3 Cylinder block
9 Exhaust purification module
4 Switchable coolant pump
10 Exhaust gas recirculation module
5 Oil/vacuum pump
6 Timing drive and drive for auxiliary units
EA288 Engine
6
Brief technical description
2.0l 4-cylinder TDI for the North American Region
Cylinder block with integrated balancer shafts
608_008
Oxidizing catalytic converter and diesel particulate filter (shown here in a transverse engine configuration.)
608_049
Cylinder head with variable valve timing
608_021
7
Oil pump with integrated vacuum pump
608_017
Switchable coolant pump
608_018
Intake manifold with integrated charge air cooler
608_009
608_019
8
Specifications of 2.0l TDI engine
Torque-power curve
500 Nm (369 lb ft)							180 kW (241 hp)
Engine with engine code CRUA (USA)
450 Nm (332 lb ft)							160 kW (214 hp)
	  Power output in kW (hp)
	  Torque in Nm (lb ft)
400 Nm (295 lb ft)							140 kW (188 hp)
350 Nm (258 lb ft)							120 kW (161 hp)
300 Nm (221 lb ft)							100 kW (134 hp)
250 Nm (184 lb ft)							80 kW (107 hp)
200 Nm (148 lb ft)							60 kW (80 hp)
150 Nm (111 lb ft)							40 kW (54 hp)
100 Nm (74 lb ft)							20 kW (27 hp)
625_082
1000
2000
3000
Engine speed [rpm]
Engine code
9
5000
625_023
CRUA
Type
Displacement in cm
4000
Four-cylinder in-line engine
3
1968
Stroke in mm
95.5
Bore in mm
81.0
Cylinder spacing in mm
88.0
Number of valves per cylinder
4
Firing order
1–3–4–2
Compression ratio
16.2 : 1
Power output at rpm
110 at 3500 – 4000 (147.5 hp at 3500 - 4000)
Torque at rpm
320 at 1750 – 3000 (236.0 lb ft at 1750 - 3000)
Fuel
ULSD (Ultra Low Sulfur Diesel) with a sulfur content of 15 ppm or less; must meet
ASTM D975 Grade 2 S15 specifications
Engine management system
Bosch EDC 17
Maximum injection pressure in bar
2000
Emission standard
BIN 5 – Tier 2
CO2 emission in g/km
106
Engine mechanicals
Cylinder block
The cylinder block is made from an alloy of cast iron and
nodular graphite (GG GJL 250).
The threads for the cylinder head bolts have been relocated
to a position lower in the block.
The net effect of lowering the threads is to ensure an even
distribution of forces produced by the engine throughout
the cylinder block. It also helps ensure an equal pressure
distribution over the entire surface area of the cylinder
head gasket.
The cylinders are surfaced honed after a torque plate has
been bolted to the cylinder block. The use of the plate
ensures that there will be no bore distortion in the cylinder block once the cylinder head has been mounted and
tightened to the proper torque specification. This also
reduces the stress on the piston rings which in turn
reduces friction. This process also leads to less blow-by
gas and oil consumption.
The cylinder block has the following technical features:
•
•
•
•
Integrated balancer shafts above the crankshaft
Short-path water jacket for rapid component heating
Optimal cooling of the webs between the cylinders
Optimized oil and water circuits to facilitate ITM
Cylinder block
Balancer shaft
Baffle plate/oil windage tray
Oil pan
608_016
10
Crankshaft assembly
The trapezoidal connecting rods are cracked at the lower
end as on previous engines.
A forged crankshaft with five bearings is used in the EA288
engine. To reduce weight, the crankshaft only has four
counterweights to counteract the rotating forces of inertia.
The load on the crankshaft bearings is also reduced by this
measure.
The pistons have no valve pockets. This design of the piston
crown reduces the dead space and improves the swirl formation of the intake air in the cylinder.
Noise emissions, which may be caused by the engine’s
inherent movement and vibrations, have also been reduced.
The toothed belt sprocket for the camshaft drive belt and
the sprocket for the oil pump drive have been press-fit to
the crankshaft.
Oil pump chain sprocket
The piston ring zones are cooled by engine oil via spray jets
fed from a piston cooling gallery in the cylinder block. (See
page 23).
Balancer shaft 1
Balancer shaft drive sprocket
Camshaft belt
sprocket
Balancer shaft 2
608_015
11
Balancer shafts
The movement of the pistons and connecting rods as well
as the reciprocal movement of the crankshaft produce
forces that cause vibrations. To counteract these vibrations,
two balancer shafts rotate in opposite directions at twice
the engine speed.
The shafts and idler gear are fixed in position radially and
axially by roller bearings. The bearings are lubricated with
oil spray from the cylinder block. Lubricating the roller
bearings in this manner reduces the drag effect at low
engine temperatures and high engine speeds.
The balancer shafts are driven by a helical-cut gear mounted
on the crankshaft. The direction of Balancer shaft 1 is
reversed through the use of an idler gear.
Roller bearing
Balancer shaft 2
Roller bearing
Balancer shaft drive sprocket
Balancer shaft 1
Crankshaft
Idler gear
for direction reversal
608_034
12
Toothed belt drive
The camshafts, high pressure fuel pump and engine coolant
pump are all driven by the crankshaft via a toothed belt.
The toothed belt is tensioned by an spring operated automatic belt tensioner. Two idler rollers ensure better
meshing of the toothed belt to the drive sprockets.
Camshaft sprocket
Idler roller
Automatic tensioning pulley
Crankshaft
Idler roller
Coolant pump
High pressure
fuel pump
608_023
13
Auxiliary component drive
Two auxiliary components - the alternator and the air
conditioning compressor - are driven by the crankshaft with
a poly V-belt. The pulley on the crankshaft also serves as a
vibration damper.
The poly V-belt is tensioned by a spring-loaded belt tensioner.
Automatic tensioning pulley
Alternator
Crankshaft
vibration damper
A/C compressor
608_035
14
Cylinder Head
The cylinder head of the engine is a cross-flow design made
of aluminum alloy. The valves are operated by two overhead camshafts integrated into a separate housing module.
One camshaft is driven by the toothed drive belt. The
second camshaft is driven by a spur gear attached to the
first.
Because of the valve layout for the cylinders, each camshaft
controls both intake and exhaust valves.
Cylinder Head
Camshaft Housing
608_022
Camshaft housing
The camshafts are integrated into a closed retaining frame
using a thermal joining process and cannot be separated
from the frame. This design ensures a rigid support for the
camshaft bearings while keeping weight low.
The sender wheel for Camshaft Position Sensor G40 is
located on one camshaft. It provides the ECM the current
position of both camshafts.
To reduce friction, the first bearing (which is subjected to
the highest load forces of the toothed drive belt) is a needle
bearing.
Hall Sensor G40
Camshaft adjuster
Retaining frame with camshafts
608_020
Note
The camshafts can only be replaced together with the housing if repairs are necessary.
15
Layout of the valves
The layout of the valves in the cylinder has been changed
when compared to the previous generation diesel engine.
The position of the valves (sometimes referred to as the
‘valve star’) has been rotated to the longitudinal axis of
the engine. This means that the intake and exhaust ports
for each cylinder are positioned one behind the other in
the direction of flow.
It also means that each camshaft actuates one intake
and one exhaust valve per cylinder. The valve layout was
re-designed to allow maximum air delivery and enhance
the swirl effect. It also helps ensure compliance to
current and future exhaust emission standards.
Intake air
First exhaust valve,
cylinder 2
First inlet valve,
cylinder 2
Second exhaust valve,
cylinder 2
Second inlet valve,
cylinder 2
Cylinder 1
Intake side
Exhaust gas
Exhaust side
608_036
608_036
16
Cylinder head coolant jacket
The coolant jacket in the cylinder head is divided into upper
and lower sections. The lower coolant jacket core has a
larger volume, ensuring there is a high level of heat dissipation in the part of the cylinder head close to the combustion chamber. The two cores in the cast part of the cylinder
head are separate.
When the engine is cold, the coolant is channelled out of
the upper and lower core, through the connecting piece and
towards the heat exchanger for the heater.
Outlet to the
connecting piece
Upper coolant jacket core
Lower coolant
jacket core
S514_047
Connecting piece for
coolant hoses
Defined cross section
Upper water jacket
Cylinder head outlet
Lower water jacket in proximity
to the combustion chamber plate
608_043
Legend for illustration on page 18:
1
2
3
4
5
6
7
8
9
17
Fuel Pressure Regulator Valve N276
High pressure fuel reservoir
Fuel Pressure Sensor G247
Fuel injector clamps
Fuel injectors
Positive crankcase ventilation and vacuum reservoir
Cylinder head cover
Pressure accumulator for the variable valve timing
Intake manifold module with integrated charge air
cooler
10
11
12
13
14
15
16
17
18
Camshaft Adjustment Valve 1 N205
Needle bearing
Bearing frame with camshafts
Roller-type cam follower
Camshaft 1 valves
Camshaft 2 valves
Cylinder head
High pressure EGR duct
Fuel distributor rail with high pressure EGR valve
Component overview
3
4
1
2
5
6
11
7
8
12
13
9
10
14
15
18
16
17
608_020
18
Variable camshaft timing
Introduction
Swivel motor
Variable camshaft timing is currently only used on engines
that must meet the EU6 or BIN5 Tier 2 emission standard.
Multiple variables can be controlled through camshaft
timing adjustments.
For example, a swirl charge motion can be induced by using
variable intake openings which make the use of a separate
swirl flap unnecessary. Another alternative is to adapt the
intake valve timing for advanced and/or retarded closing
which allows NOx and CO2 emissions to be reduced. Compression can also be effectively reduced by means of a
variable intake timing mechanism. This would result in
lower compression temperatures and in turn, reduce NOx
emissions.
Piston pressure
accumulator
Camshaft Position Sensor G40
608_021
The current technical innovations allow
• Optimized volumetric efficiency at full throttle
• Optimized emission reduction and fuel efficiency through
variable (and thus more effective) compression
• Maximum combustion pressure expansion utilization
• High compression ratios at cold start
Valve travel
In addition to reducing emissions, future technical developments will focus on reducing fuel consumption.
Variable valve timing is done by a hydraulically moving
(engine oil pressure) a swivel motor in the camshaft
adjuster.
When the engine is started, the swivel motor is held in the
advanced timing position by a locking element until the
required oil pressure is reached.
The active adjustment range for the intake and exhaust
valves is 50 degrees of crankshaft angle after retard.
BDC		TDC		BDC
Key:
1
2
3
Exhaust:
Intake:
Intake:
608_037
variable opening
variable opening
variable closing
Advance: both intake valves open simultaneously
Retard: only the rear intake valve on the “exhaust side”
opens;opening of the second intake valve is
delayed
Design
Swivel motor (stator)
Camshaft Adjustment Valve 1 N205
Cover with gear
Swivel motor (rotor)
Mechanical locking element
Cover
Spring
19
Control valve for camshaft timing adjustment
608_053
Function
The engine oil pump supplies the swivel motor with pressurized oil via a separate oil gallery in the cylinder head.
Adjustment is controlled by the ECM through a 4/2-way
proportioning valve. The ECM provides a pulse-widthmodulated signal to activate the valve.
The inner vane ring (rotor) of the swivel motor is connected
to the camshaft. The outer ring (stator) is attached to a
gear which in turn engages a gear of the belt driven camshaft. The camshaft is adjusted relative to the crankshaft
by applying oil pressure to working chambers between the
rotor and stator.
Mesh oil filter
Non-return valve
Swivel motor (rotor)
Piston pressure
accumulator
Swivel motor (stator)
Mechanical locking element
Camshaft Adjustment Valve 1 N205
Control valve for camshaft
timing adjustment
Airflow – at retarded ignition timing during the
intake cycle
608_010
Cross-section view of swivel motor
Return spring
Control valve
Camshaft Adjustment Valve 1 N205
Swivel motor (stator)
Piston pressure
accumulator
Swivel motor (rotor)
608_060
Camshaft
608_054
20
Operating ranges
A swivel motor must be subjected to a high volumetric oil
flow during the adjustment cycle to make a rapid control
response. To ensure a rapid response in the first stage at a
low pressure level, a pressure accumulator is integrated
with the adjuster. The holding pressure inside the accumulator can be up to 1.8 bar. N205 determines when the
pressure accumulator releases oil into the corresponding
port on the swivel motor based on information from the
ECM.
In the un-pressurized oil chamber, oil is expelled from the
swivel motor and forced into the return line. If the oil
gallery supply pressure is less than the pressure inside the
accumulator during camshaft adjustment, the adjustment
is assisted by the accumulator.
When the swivel motor reaches its end position, the oil
pressure in the accumulator is restored and the pressure in
the feed line is at gallery pressure.
N205 can adjust is such a way that both working chambers
are subjected to oil pressure. Depending on the oil pressure
conditions in the working chambers, both the rotor and the
camshaft are adjusted to either “advance” or ”retard”.
When the engine is switched off, the swivel motor is
adjusted to the “advanced” position by the return spring
and locked into its position.
E
Adjustment to advanced timing
N205
Engine oil pressure is admitted to working chamber A
through Camshaft Adjustment Valve 1 N205 which in
turn advances the rotor toward working chamber B.
C
F
D
B
A
B
A
608_013
Adjustment to retarded timing
The camshaft is locked in the “advanced” position. The
spring-loaded locking element is released when the oil
pressure is sufficient. N205 opens working chamber A
releasing the oil pressure into the return line. Oil pressure
from the pressure accumulator in working chamber B
displaces the swivel motor towards the “retard”
position.
Continuously variable valve timing is achieved by pulsewidth-modulated activation.
E
N205
F
C
D
B
A
B
A
Key:
A
A
B
C
D
21
B
608_012
Working chambers in the swivel motor
Oil pump
Engine lubrication system
Mesh oil filter
Non-return valve
E
Piston pressure accumulator
E1: Start of charging at approx. 0.6 bar
E2: End of charging at approx. 1.8 bar
F
Camshaft adjuster (swivel motor)
N205 Intake camshaft timing adjustment valve 1
Positive crankcase ventilation
After passing through the cylones, the blow-by gases flow
to the pressure control valve; additionally, they are then fed
into the combustion chamber through the intake manifold.
The components of the crankcase breather are integrated
into the polyamide cylinder head cover, together with the
oil filler neck and the pressure accumulator for the
vacuum system of the engine.
Positive Crankcase Ventilation Heating Valve N79 is used to
prevent the freezing of the residual moisture of the blow-by
gases during cold weather operation.
Separation of the coarse and fine oil from the blow-by
gases as well as the pressure regulation of the crankcase
also occurs in the cylinder head cover. The blow-by gases
from the crankcase flow to the coarse oil separator through
small ports and then into the cylone-type fine oil separation section.
Vacuum reservoir
Positive Crankcase
Ventilation Heating Valve
N79
Pressure control valve
Fine oil separation
(cyclones)
Oil return from fine oil separator
Gravity valve for oil recirculation
608_051
22
Oil supply
Oil circuit
Engine oil pressure is generated by a flow-rate controlled
oil pump. It is driven by the crankshaft via a separate
toothed belt. The oil pressure can be switched to a high
or a low pressure stage via the pump.
Oil pressure accumulator for variable camshaft timing
Camshaft oil gallery
Longitudinally mounted
oil filter module
Turbocharger oil supply
Oil gallery of the
hydraulic lifters
Oil Pressure Switch
F22
Reduced Oil Pressure
Switch F378
Two-stage oil pump
Piston cooling jets
Crankshaft oil gallery
Oil Level Thermal Sensor G266
608_024
23
Oil pump with integral vacuum pump
A combined oil/vacuum pump is located in the oil pan and
bolted directly to the cylinder block. It is driven by a
toothed belt. The toothed belt is immersed in engine oil
and has no belt tensioner. The tightness of the belt is
determined solely by the spacing between the components.
Oil pump toothed belt cover
with integrated crankshaft ring seal
Oil/vacuum pump integrated in the oil pan
Drive via
separate toothed belt
Connections to the vacuum supply and oil circuit
608_017
Oil Pressure Regulation Valve N428 is installed above the
sump in the cylinder block. There is a connection for the
vacuum line which leads to the engine vacuum system
directly next to this. The vacuum line is connected to the
vacuum pump by a gallery in the cylinder block.
Vacuum line from cylinder block
to vacuum equipment
Oil Pressure Regulation Valve N428
Passage to main oil gallery
Combined oil/vacuum pump integrated in the oil pan
608_038
24
Design
The oil pump is a flow-rate controlled vane pump on which
the eccentrically mounted adjustment ring allows the
delivery characteristics of the pump to be regulated. The
position of the rotating adjustment ring changes the flow
rate of the pump, and therefore allows the drive output of
the pump to be adapted to the engine’s operating
conditions.
A specially shaped engine oil pick-up ensures reliable oil
intake from the oil pan even when the vehicle is subjected
to high transverse acceleration in high speed turns and
banking.
By applying oil pressure to the adjustment ring via a control
surface, it can be swivelled against the force of the control
spring.
The air is drawn through flutter valves into the cylinder
block and ventilates its inner chamber. This air is then
admitted into the combustion chamber via the engine
breather as blow-by gas.
Vacuum
pump cover
Housing
Rotor with
vacuum pump vane
The vacuum pump inducts air from the brake servo through
a vacuum line and ports in the cylinder block.
Flutter valve
Double flutter valve
Control piston
Toothed drive pulley
Adjustment ring
Rotor with
vane cells
Oil pressure relief valve
Engine oil pick-up
Control spring
Oil pump cover
608_025
Oil pressure control
The oil pump operates in two pressure stages, which are
activated depending on engine speed.
Low pressure stage: oil pressure 1.8 – 2.0 bar
2
High pressure stage: oil pressure 3.8 – 4.2 bar
25
Oil pressure [bar]
1
2
1
Engine speed [rpm]
608_078
Function
Low delivery rate
Control surface
At low engine speeds, Oil Pressure Regulation Valve N428 is
energized when the ECM connects it to ground. This opens
the active passage to the control piston. The oil pressure
now acts on both faces of the control piston, pushing the
piston against its spring and opening the passage to the
control surface of the adjustment ring.
Adjustment ring
Small delivery chamber
The oil pressure now acts on the control surface of the
pump. The force is greater than the control spring and
swivels the adjustment ring counter-clockwise into the
center of the vane cell pump which reduces the delivery
space between the vane cells.
This lower pressure stage is activated dependent on engine
load, engine speed, oil temperature and other operating
parameters which in turn reduces the drive output requirement of the pump.
Vane cells
Control spring
Control piston
608_026
Control piston spring
Oil pan
Control piston
Non-return valve
Active oil passage
N428
Oil pressure from the oil
gallery
608_055
26
High delivery rate
Large delivery chamber
At high engine speed or load (for example, full throttle
acceleration), Oil Pressure Regulation Valve N428 is deenergized by the ECM which in turn vents the active oil
passage. The force of the remaining surface under oil
pressure is less than the force of the control piston spring
and closes the oil passage to the control surface of the
adjustment ring.
Support bracket
Control surface
Without oil pressure, the control spring swivels the adjustment ring clockwise around the center bearing. The adjustment ring now swivels out of its center position and
increases the delivery space between the individual vanes
which increases oil delivery. The higher volumetric oil flow
is countered by the size of the oil galleries and crankshaft
bearing play causing the oil presssure to increase.
If communication with the ECM is lost, spring force will
move the control surface to the high delivery position. This
ensures that the engine components are protected.
608_027
Control piston spring
Control piston
Active oil passage
N428
Control edge
Oil pan
Non-return valve
Oil pressure from the oil gallery
608_056
Note
The maximum rate of delivery is always available when the solenoid valve is de-engerized.
27
Oil filter module
The oil filter module consists of the oil cooler, which is
mounted to the side of the oil filter module, as well as the
oil filter bypass valve and oil cooler bypass valve.
Depending on the engine’s installation position, there are
two different oil filter modules.
Longitudinally mounted engines
Components:
• Upright oil filter housing with oil drain valve
• Filter cartridge
• Reduced Oil Pressure Switch F378 (0.3 – 0.6 bar)
• Oil Pressure Switch F22 (2.5 – 3.2 bar)
Filter cartridge
Coolant return line
from the oil cooler
Oil Pressure
Switch F22
Oil return line
to the engine lubrication points
Reduced Oil
Pressure Switch F378
Coolant feed line
to the oil cooler
Oil cooler
Oil feed line
from the oil pump
608_045
28
Transversely mounted engines
•
•
•
•
Upright oil filter housing with oil drain valve
Filter cartridge
Reduced Oil Pressure Switch F378 (0.3 – 0.6 bar)
Oil Pressure Switch F22 (2.5 – 3.2 bar)
Oil cooler
Coolant return line
from the oil cooler
Oil Pressure
Switch F22
Oil filter bypass valve
Oil return line
to the engine lubrication points
Reduced Oil Pressure
Switch F378
Coolant feed line
to the oil cooler
Filter cartridge
Oil feed line
from the oil pump
608_046
29
Cooling system
Thermal management
Cylinder head coolant valve
N489
The EA288 diesel engine uses a thermal management strategy designed to shorten the warm-up phase after a cold start
and implement emission reduction measures quickly.
The thermal management system also directs the heat produced by the engine during normal operation to where it can
be advantageously used to boost vehicle efficiency. A main
focus is to reduce intra-engine friction.
The overall cooling circuit has three sub-circuits:
• Secondary cooling circuit (micro circuit)
• Cylinder head
• EGR cooler of low pressure exhaust gas recirculation
system
• Passenger compartment heat exchanger
• Electrical auxiliary coolant pump
• Primary cooling circuit (high temperature circuit)
• Cylinder block and intake manifold
• Engine and transmission oil cooler
• Coolant thermostat (3/2-way valve)
• Main vehicle radiator
• Switchable coolant pump
608_018
Coolant pump
• Cooling circuit with charge air cooler (low temperature
circuit)
• Charge air cooler
• Charge air cooler (in front of vehicle) radiator
• Charge Air Coolant Pump V188
Switchable coolant pump
A switchable coolant pump is used in the thermal management system 2.0L TDI engine. This coolant pump can be
switched on and off, allowing coolant circulation to be
stopped when the engine is cold. Static coolant heats up
more quickly and can bring the engine to operating temperature more effectively.
A hydraulically actuated control valve activated by Cylinder
Head Coolant Valve N489 slides over the rotating impeller
and prevents the coolant from circulating.
Impeller with integrated
wobble plate
Drive shaft
Cylinder Head
Coolant Valve
N489
Annular piston
Control valve
Bearing
Pump casing
Axial-piston pump
Guide bushing with
coolant ducts
Annular piston ring seals
Compression spring for resetting
the control valve
608_029
Control valve seal
30
Coolant pump function
The control valve can slide over the impeller which will
prevent coolant from being circulated. The impeller has an
integral cast stainless steel plate that functions as a
wobble plate. An axial piston pump integrated in the pump
housing is actuated by the wobble plate. The pump recirculates the coolant to the coolant circuit via Cylinder Head
Coolant Valve N489.
Static coolant
Cylinder Head Coolant Valve N489
ON
Control valve slid
over the impeller
Axial-piston pump
When N489 is energized, the return port to the coolant
circuit closes. This happens because the lifting motion of
the axial piston pump produces a hydraulic pressure at the
annular piston. The control valve slides over the impeller
against spring tension and seals the impeller off from the
cylinder block. No coolant is circulated.
Impeller
Wobble plate with
race for axial piston
pump
608_039
Annular piston displaced
Coolant is circulated
If N489 is de-energized, the return port to the coolant
circuit opens, the ring-shaped piston is pushed back by the
compression spring and restores the control valve to its
original position.
The impeller is uncovered and the coolant begins to circulate. The axial piston pump operates whenever the engine
is running.
Cylinder Head Coolant Valve N489
OFF
Control valve retracted
Return port
open
Coolant Pump Operation 1
Coolant Pump Operation 2
608_007
31
System overview
The following diagrams show the cooling system in the engine
version which meets the EU5 exhaust emission standard.
1
2
3
5
4
6
8
7
10
9
11
16
12
17
13
14
15
18
608_073
Key:
1
2
3
4
5
6
7
8
9
Coolant expansion tank
Passenger compartment heat exchanger
Auxiliary heater (not for the North American market)
Recirculation Pump V55
Heater Support Pump V488
Engine Coolant Temperature Sensor G62
Coolant connection
EGR cooler
Cylinder Head Coolant Valve N489 (mounted on
water pump)
10
11
12
13
14
15
16
17
18
Coolant thermostat
Throttle valve
Engine oil cooler
Coolant Fan V7
Coolant Fan 2 V177
Radiator
Charge Air Cooling Pump V188
Charge air cooler integrated in intake manifold
Heat exchanger for charge air cooling
Cooled coolant
Heated coolant
32
Secondary cooling circuit (micro circuit, heating circuit)
When the engine is cold, the thermal management system
operates the cooling system in the secondary cooling circuit
mode. This ensures the engine and passenger compartment are heated quickly.
V488 provides back-up in cold ambient conditions to ensure
that a minimum volumetric flow is achieved at high coolant
viscosity.
The driver’s temperature preference is registered by the A/C
control module when V488 is activated.
Cylinder Head Coolant Valve N489 is energized and the
water pump control valve is moved to cover the impeller to
prevent coolant flow in the engine block.
At the same time, Heater Support Pump V488 operates.
Coolant flows in the secondary cooling circuit in a controlled manner depending on the coolant temperature in
the cylinder head.
1
2
3
5
4
6
8
7
10
9
11
16
12
17
13
18
14
15
608_074
33
Secondary cooling circuit – engine cooling requirements / high engine load
The switchable coolant pump is activated (N489 de-energized) at increasing engine load and engine speed. This
ensures the engine is cooled. After the engine speed drops
below a threshold level, the coolant pump is de-activated
again (N489 energized) and the engine is operated without
coolant circulation until a required temperature is achieved.
1
The coolant pump is continuously activated when the
coolant temperature exceeds a threshold level at the cylinder head, indicating that the engine is at operating temperature. When the coolant pump is activated, it is ensured
that a sufficient quantity of coolant flows through the
cylinder head. For this purpose, the engine thermostat has
its own integrated by-pass (short circuit). (refer to p. 37).
2
3
5
4
6
8
7
10
9
11
16
12
17
13
14
15
18
608_075
Key:
1
2
3
4
5
6
7
8
9
Coolant expansion tank
Passenger compartment heat exchanger
Auxiliary heater (not for the North American market)
Recirculation Pump V55
Heater Support Pump V488
Engine Coolant Temperature Sensor G62
Coolant connection
EGR cooler
Cylinder Head Coolant Valve N489 (mounted on
water pump)
10
11
12
13
14
15
16
17
18
Coolant thermostat
Throttle valve
Engine oil cooler
Coolant Fan V7
Coolant Fan 2 V177
Radiator
Charge Air Cooling Pump V188
Charge air cooler integrated in intake manifold
Heat exchanger for charge air cooling
Cooled coolant
Heated coolant
34
Primary cooling circuit (high temperature circuit) – coolant at operating temperature
If the coolant is at operating temperature, the coolant
thermostat opens and enters control mode. The radiator
(main radiator) is integrated in the cooling circuit.
1
The coolant thermostat controls the engine outlet temperature and is located in the main radiator feed line.
2
3
5
4
6
8
7
10
9
11
16
12
17
13
18
14
15
608_076
35
Low temperature cooling circuit – coolant circuit for charge air cooling
temperature is regulated by activating Charge Air Cooling
Pump V188.
The intake manifold temperature is used as a reference
variable for activating the charge air cooling circuit. After
this targert temperature is achieved, the intake manifold
1
2
3
5
4
6
8
7
10
9
11
16
12
17
13
14
15
18
608_077
Key:
1
2
3
4
5
6
7
8
9
Coolant expansion tank
Passenger compartment heat exchanger
Auxiliary heater (not for the North American market)
Recirculation Pump V55
Heater Support Pump V488
Engine Coolant Temperature Sensor G62
Coolant connection
EGR cooler
Cylinder Head Coolant Valve N489 (mounted on
water pump)
10
11
12
13
14
15
16
17
18
Coolant thermostat
Throttle valve
Engine oil cooler
Coolant Fan V7
Coolant Fan 2 V177
Radiator
Charge Air Cooling Pump V188
Charge air cooler integrated in intake manifold
Heat exchanger for charge air cooling
Cooled coolant
Heated coolant
36
Coolant thermostat
The coolant thermostat (3/2-way valve) is activated by an
expanding wax element, which begins to close the secondary cooling circuit when operating temperature is reached.
The primary cooling circuit is closed at the same time.
Secondary cooling circuit (micro circuit)
Connection to main
radiator closed
from
cylinder block
By-pass (short circuit) to
coolant pump open
608_005
Primary cooling circuit (high temperature circuit, controlled)
Connection to main
radiator open
from
cylinder block
By-pass (short circuit) to
coolant pump closed
608_006
37
Coolant expansion tank with silicate repository
There is a silicate repository in the coolant expansion tank.
The silicate is used to protect the aluminium components
in the coolant circuit from corrosion. The silicates in the
coolant G13 dissipate over time if the engine is subject to
high thermal loads.
To compensate for the silicate consumption, silicate is
taken from the repository and added to the coolant. The
silicate repository is therefore used as additional protection
against corrosion for aluminium components in the coolant
circuit over the entire lifespan of the engine. The silicate
repository is not a serviceable item and it is designed to
last for the life of the vehicle.
Engine Coolant Level Sensor G32
Coolant expansion tank
Coolant return
Silicate container
Silicate
Coolant supply
s514_079
38
Fuel System
4
6
9
7
8
10
5
11
12
12
12
12
1
3
2
Key:
Fuel high pressure maximum 1800 bar
Fuel return 0 - 1.0 bar
s514_027
Fuel supply pressure 3.5 - 5.0 bar as required
Fuel return pressure from the injectors 0.4 - 1.0 bar
1 - Fuel Pump Control Module J538
J538 controls the pressure in the fuel supply and monitors the
function of the fuel pump as required.
7 - Fuel Pressure Regulator Valve N276
N276 is used to adjust the fuel pressure in the high-pressure
range.
2 - Transfer Fuel Pump G6
G6 generates the fuel pressure in the fuel supply.
8 - High-Pressure Accumulator (rail)
The high-pressure accumulator stores the fuel required for
injection into all cylinders under high pressure.
3 - Fuel Filter
The fuel filter keeps impurities in the diesel fuel from the
components of the injection system. The high precision components, for example, the high-pressure pump and the injectors,
can be damaged or their function impaired by even the most
minute particles of dirt.
9 - Fuel Pressure Sensor G247
G247 measures the current fuel pressure in the high-pressure
area.
4 - Fuel Temperature Sensor G81
G81 measures the current fuel temperature.
10 - Pressure Retention Valve
The pressure retention valve ensures a constant pressure of
about 1 bar in the return of the injectors. This avoids variations
in pressure and allows precise control of the injectors.
5 - High-Pressure Pump
The high-pressure pump generates the high fuel pressure
required for injection.
11 - Pulsation Damper
The pulsation damper has the task of reducing distracting
noises caused by pulsating fuel in the fuel return line.
6 - Fuel Metering Valve N290
N290 regulates the quantity of fuel needed to generate the
high pressure as required.
12 - Injectors N30, N31, N32, N33
The injectors inject the fuel into the combustion chambers.
39
Fuel injectors
The fuel injectors are controlled by a solenoid valve actuator.
Bosch has developed an injector with solenoid valve technology that fulfils the requirements for high injection
pressures and the ability to perform several injections per
work cycle. Solenoid valve-controlled injectors have the
advantage that they are simpler to manufacture than
injectors with a piezo actuator.
Injector
Clamping piece
Clamping piece
s514_029
40
Injector in rest position
Design
In its rest position, the injector is closed. The solenoid is
not actuated. The solenoid valve armature is pushed into its
seat by the force of the solenoid valve spring and thus
closes the path from the valve control chamber to the fuel
return. The fuel is under high pressure in the valve control
chamber. Due to the larger pressure/surface ratio of the
control piston surface to the injector needle, the injector
needle is pushed into its seat and closes the injection
nozzle.
Fuel return
High-pressure fuel connection
Valve control chamber
Spring
Solenoid
Armature
Stay bolt
Outflow choke
Valve control chamber
Control piston
Inflow choke
Injector needle
s514_049
Key:
High pressure
Return pressure
41
Start of injection
The solenoid is activated by the ECM to initiate the injection
cycle. As soon as the magnetic force exceeds the closing
force of the solenoid valve spring, the solenoid valve armature moves upwards, opening the outflow choke. The fuel in
the valve control chamber flows via the opened outflow
choke into the fuel return line. The fuel pressure in the
valve control chamber falls. The inflow choke prevents rapid
pressure equalization between the fuel high-pressure
section and the valve control chamber. The injector needle
is raised by the high fuel pressure and injection begins
Fuel return
High-pressure fuel connection
Valve control chamber
Spring
Solenoid
Armature
Stay bolt
Outflow choke
Valve control chamber
Control piston
Inflow choke
Injector needle
s514_050
Key:
High pressure
Return pressure
42
Pre-heating the fuel filter
When the fuel temperature is cold, warmed fuel from the
high-pressure accumulator (rail) is directed into the supply
line upstream of the fuel filter. This prevents the fuel filter
becoming clogged with crystallized paraffins.
To allow the fuel to be warmed quickly when the engine is
cold, Fuel Metering Valve N290 supplies more fuel than is
required for injection to the pressure chamber of the
high-pressure pump. The fuel warmed during pressurization is sent from the high-pressure accumulator (rail) via
Fuel Pressure Regulator Valve N276 into the fuel filter
return line.
2
5
3
6
4
1
s514_108
Key:
1
Fuel filter
4
High-pressure pump
2
Fuel Temperature Sensor G81
5
High-pressure accumulator (rail)
3
Fuel Metering Valve N290
6
Fuel Pressure Regulator Valve N276
43
Pulsation damper
A pulsation damper is integrated near the plenum chamber
bulkhead in the fuel return line. It has the task of reducing
distracting noises caused by pulsating fuel in the fuel
return line.
To reduce the pulsation in the fuel return line, a cushion of
air builds up in the pulsation damper when the engine is
running. The air cushion absorbs the pressure pulsations in
the fuel return line and thereby reduces the vibrations.
s514_052a
Pulsation damper
Pulsation damper
Air cusion
Pulsation damper
1
Air cusion
2
Fuel return
Fuel return
s514_057
s514_058
44
Engine management system
System overview
Sensors
Mass Airflow Sensor G70
Throttle Position Sensor G69
Engine Speed Sensor G28
Hall Sensor G40
Engine Coolant Temperature Sensor G62
Fuel Temperature Sensor G81
NOx Sensor Control
Module J583
Engine Coolant Temperature Sensor on Radiator Outlet G83
Oil Level Thermal Sensor G266
Fuel Pressure Sensor G247
NOx Sensor G295
Accelerator Pedal Position Sensor G79 and
Accelerator Pedal Position Sensor 2 G185
Exhaust Gas Recirculation Position Sensor 2 G466
Charge Pressure Actuator Position Sensor G581
NOx Sensor Control Module 2
J881
Brake Light Switch F
Brake Pedal Switch F63
NOx Sensor 2 G687
Heated Oxygen Sensor G39
Charge Air Temperature Sensor in front of Charge Air Cooler G810
Charge Air Temperature Sensor after Charger Air Cooler G811
Charge Pressure Actuator Position Sensor G581
Oil Pressure Switch F22
Reduced Oil Pressure Switch F378
Engine Control
Module J623
Exhaust Gas Temperature Sensor 3 G495
EGR Temperature Sensor G98
Data Link Connector
Exhaust gas Temperature Sender 1 G235
Exhaust Gas Temperature Sensor 4 G648
Charge Air Pressure Sensor G31
Differential Pressure Sensor G505
Auxiliary signals:
−− Cruise control system
−− Speed signal
−− Start request to ECM (Kessy 1 + 2)
−− Terminal 50
−− Crash signal from Airbag Control Module
45
Private CAN bus
Combustion Chamber Pressure Sensors G677 - G680
Actuators
Injectors, cylinders 1 – 4
N30, N31, N32, N33
Automatic Glow Time Control Module J179
Glow plugs 1 – 4 Q10, Q11, Q12, Q13
Oil Pressure Regulation Valve N428
Throttle Valve Control Module J338
Fuel Metering Valve N290
Fuel Pressure Regulator Valve N276
EGR Motor V338
(Low pressure exhaust gas recirculation)
EGR Motor 2 V339
(High pressure exhaust gas recirculation)
EGR Cooler Switch Over Valve N345
(EU4)
Cylinder Head Coolant Valve N489
Charge Air Cooling Pump V188
Wastegate Bypass Regulator Valve N75
Heater Support Pump V488
Exhaust Door Control Unit J883
Positive Crankcase Ventilation Heating Element N79
(cold-climate countries only)
Fuel Pump Control Module J538
Oxygen Sensor Heater Z19
Reducing Agent Metering System Control Module J880
Reducing Agent Injector N474
Reducing Agent Line Heater (heating circuit 2) Z104
Reducing Agent Pump V437
Reducing Agent Tank Heater (heating circuit 1) Z102
Fuel Pump Relay J17
Transfer Pump G6
Auxiliary signals:
−−
A/C compressor
−−
Auxiliary coolant heater
−−
Fan setting 1 + 2
−−
Auxiliary air heater element Z35
608_058
46
Glow plug system
The EA288 engine for the North American market uses a
rapid start glow plug system. The advantages of this
system are:
•
Engine start comparable to a gasoline engines at
temperatures down to -24 °C
•
Extremely short heating time. Within 2 seconds, the
glow plug temperatures reach up to 1000 °C
•
Controllable temperatures for preglow and afterglow
phases
•
Self-diagnostic ability
Overview of the system
Engine Control
Module J623
Glow plug 1 Q10
Engine Speed
Sensor G28
Automatic Glow Time
Control Module J179
Glow plug 2 Q10
Engine Coolant
Temperature Sensor
G62
Data Bus Onboard
Diagnostic Interface
J533
Glow plug 3 Q10
Vehicle Electrical System
Control Module 1 J519
Glow plug 4 Q10
Instrument Cluster
Control Module
J285
Glow period warning
lamp K29
s514_081
Pressure Sensing Glow Plugs
47
Function
Pre-glowing
For rapid starting at an exterior temperature of less than
24 °C, there is a maximum of 11.5V. This ensures the glow
plug is heated to over 1000 °C within a short period of time
(approximately 2 seconds). This reduces the pre-glow time
for starting.
Engine Control Module J623 determines when to activate
the steel glow plugs via Automatic Glow Time Control
Module J179. J179 uses a PWM signal to activate the
plugs. The voltage of the individual glow plug is adjusted
via the duty cycle.
Post-start glowing
For post-start glowing, the switch-on time of the supply
voltage is adjusted in the PWM duty cycle to ensure that
there is an effective voltage of 4.4 V. Post-start glowing is
carried out for a maximum of 5 minutes after starting the
engine up to a coolant temperature of 24 °C. Post-start
glowing helps reduce hydrocarbon emissions and combustion noises during the warm-up phase.
On vehicles with a start/stop system, the post-start
glowing process is not interrupted if the engine-stop function is active. This avoids frequent temperature changes
and protects the material of the steel glow plug.
Phase-shifted activation of the glow plugs
Glow plug
To relieve the load on the supply voltage during the glow
phases, the glow plugs are actuated in a phase-shifted
manner. The falling signal actuates the next glow plug.
Cylinder 1
Cylinder 2
Cylinder 3
Cylinder 4
s514_040
48
Air regulation overview
All pressure figures, temperature values and mass flows on
the intake air, charge air and exhaust lines of the engine are
measured. These values are used to regulate the charge
pressure, the cylinder filling and the exhaust gas recirculation rate. The advantage of this model is that the complex
air regulation system of the engine manages with a limited
number of sensors despite a large number of actuators.
The higher demands placed on exhaust gas after-treatment
in the future require an enhanced control and regulation
structure for both the air intake and exhaust of the engine.
The air regulation system of the engine is based on a model
that calculates conditions in all operational states of the
engine.
12
4
1
2
3
13
5
6
7
11
8
9
14
20
15
10
19
17
16
18
s514_035
Key:
1
2
3
4
5
6
7
8
9
10
49
Intake Air Temperature Sensor G42
Charge air cooler
Charge Air Temperature Sensor after Charge Air
Cooler G811
Exhaust Gas Temperature Sensor 3 G495
Oxidizing catalytic converter
Heated Oxygen Sensor G39
Exhaust Gas Temperature Sensor 1 G235
Exhaust turbine with variable vanes
Wastegate By-pass Regulator Valve N75
Charge Pressure Actuator Position Sensor G581
11
12
13
14
15
16
17
18
19
20
Exhaust Gas Temperature Sensor 4 G648
Differential Pressure Sensor G505
Diesel particulate filter
Exhaust Door Control Unit J883
Exhaust gas recirculation cooler
EGR Motor 2 V339
Turbocharger compressor
Mass Airflow Sensor G70
Throttle Valve Control Module J338
Charge Air Pressure Sensor G31
Turbocharger / exhaust manifold module
The turbocharger is integrated with the exhaust manifold
to form a single module. The turbocharger is equipped with
adjustable guide vanes (Variable Turbine Geometry) which
allows the flow of exhaust gas into the turbine impeller to
be regulated. The guide vanes are adjusted by an actuating
link operated by a vacuum motor.
The recirculated exhaust gases are not extracted at the
turbine housing, rather at the diesel particulate filter
outlet. The full mass flow is always channeled through the
turbocharger compressor by extracting the recirculated
exhaust gases downstream of the diesel particulate filter
outlet.
(Longitudinal installation shown)
The turbocharger operates with greater efficiency. This
allows higher charge pressures and higher volumetric
efficiency to be achieved at part loads in particular. A
benefit of this is the higher cooling capacity of the exhaust
gas recirculation system, which helps to reduce the mixing
temperature of the fresh air and recirculated exhaust
gases.
The acoustic characteristics of the exhaust turbocharger
were improved by using modified damping chambers in the
baffled sound absorber.
Vacuum motor
Vacuum connection
VTG actuating lever
Intake air from
air filter
Integral insulation
Exhaust manifold
Blow-by gases
of the positive
crankcase
ventilation
system
To intake
manifold
Oil return line
Positive Crankcase Ventilation
Heating Element N79
from EGR cooler
and EGR valve
Oil feed line
608_079
50
Charge pressure control
Wastegate By-pass Regulator Valve N75
N75 is actuated by the engine control module using a duty
cycle (PWM). It switches the control pressure in the vacuum
motor to move the variable vanes of the turbocharger.
Effects of failure
The variable vanes of the turbocharger are moved to a
steep working position which results in a low charge pressure when the engine speed is low. The engine has less
power and active regeneration of the diesel particulate
filter is not possible.
1
2
3
4
5
6
11
7
10
8
9
S514_107
Key:
1
2
3
4
5
6
51
Intake Air Temperature Sensor G42
Charge Air Cooler
Charge Air Temperature Sensor after Charge Air Cooler G811
Exhaust Gas Temperature Sensor 1 G235
Exhaust Turbine with variable vanes
Wastegate By-pass Regulator Valve N75
7
8
9
10
11
Charge Pressure Actuator Position Sensor G581
Turbocharger Compressor
Mass Airflow Sensor G70
Throttle Valve Control Module J338
Charge Air Pressure Sensor G31
Charge Air Pressure Sensor G31
Throttle Valve Control Module J338
Signal use
The throttle valve module is installed in the intake track
before the charge air cooler. There is an electric motor in
the throttle valve module that operates the throttle valve
via gears. Adjustment of the throttle valve is infinite and
can therefore be adapted to the respective engine operating situation. The position of the throttle valve is used to
regulate the air pressure and the intake air quantity in the
intake manifold. During regeneration of the diesel particulate filter, the throttle valve regulates the quantity of
intake air and therefore the oxygen supply. The valve is
closed when the engine is switched off. In this way, less air
is drawn in and compressed, which results in the engine
shutting down softly.
The signal from G31 allows the ECM to determine the air
pressure in the intake manifold and regulate charge pressure.
Effects of failure
There is no substitute function in the event of signal
failure. Charge air pressure regulation is shut off and there
is a significant reduction in engine output. The particulate
filter cannot be actively regenerated.
Intake Air Temperature Sensor G42
Effects of failure
Signal use
In the event of failure of the throttle valve module, correct
regulation of the intake manifold pressure is no longer
possible. There is no active regeneration of the diesel
particulate filter.
The signal from G42 is used by the ECM to regulate charge
pressure. Because temperature affects the density of the
charge air, the ECM uses the signal as a correction value.
Effects of failure
If G42 fails, the ECM uses a fixed substitute value for
calculation purposes.
Ambient Air Pressure Sensor
An ambient air pressure sensor is installed in the ECM. As
the density of the intake air decreases as altitude increases,
the air pressure is used as a correction value for charge
pressure control.
Charge Pressure Actuator Position
Sensor G581
Signal use
G581 provides the ECM with the position of the turbocharger variable guide vanes. In conjunction with G31, the
condition of the charge pressure regulation can be determined.
Throttle Position Sensor G69
G69 is integrated into the throttle valve module. The
sensor elements detect the current position of the throttle
valve.
Signal use
The ECM uses the signal to identify the current position of
the throttle valve in the intake manifold. This information
is required for regulation of the intake manifold pressure
and regeneration of the particulate filter.
Effects of failure
If the sensor fails, the engine will be run in emergency
mode with reduced power. No active regeneration of
the diesel particulate filter takes place.
Effects of failure
If G581 fails, the signal of the charge air pressure sensor
and the engine speed sensor are used by the ECM to determine the position of the guide vanes.
52
Charge air cooler
A charge air cooler is integrated with the intake manifold.
This provides the following advantages:
•
The intake manifold temperatures are adjustable
within defined limits, the system can operate independently of the intake air temperature and the recirculated exhaust gas.
•
A compact charge air circuit with reduced flow losses.
•
Icing and condensation are avoided in the charge air
cooler.
The charge air cooler operates according to the same principle as a heat exchanger.
Connecting flange
Charge air temperature sensor
after charge air cooler G811
Charge air cooler
Conduit
Charge air
pipe
Intake air temperature
sensor G42
Throttle valve control
module J338
Connection for charge
pressure sensor G31
Intake manifold temperature regulation
To regulate the intake manifold temperature to a specific
value, Charge Air Cooling Pump V188 is actuated by the
ECM based on the requirements. The duty cycle to actuate
the pump depends on the temperature measured by Charge
Air Temperature Sensor after Charge Air Cooler G811 and a
map in the ECM.
53
s514_061
Charge Air Temperature Sensor after
Charge Air Cooler G811
Charge Air Cooling Pump V188
Usage
Signal use
The signal from G811 is required:
•
•
to calculate the necessary duty cycle for actuating the
charge air cooling pump and therefore for regulating
the intake manifold temperature.
to protect components. If the air temperature in the
intake manifold exceeds a critical value, the engine
power is reduced.
V188 is actuated by the ECM with a PWM signal based on
engine requirements. It draws engine coolant from main
engine radiator and pumps it to the charge air cooler.
Effects of failure
If V188 fails, a DTC is logged in the ECM fault memory and
Malfunction Indicator Lamp K83 lights. If the intake manifold temperature exceeds a critical value, engine output is
reduced to protect components.
Effects of failure
In the event of sensor failure, the engine control unit
employs a fixed value for calculation purposes.
Intake Air Temperature Sensor G42
Signal use
G42 is used by the ECM to monitor the efficiency of the
charge air cooler. The temperatures from before and after
the cooler are compared by the ECM.
Effects of failure
If G42 fails, the ECM uses a fixed value for calculation purposes.
54
Exhaust system
Longitudinally
mounted engines
Oxidizing catalytic converter
Exhaust Door Control Unit
J883
Center muffler
Diesel particulate filter
Flex tube
Oxidizing catalytic converter
Transversely mounted engines
Exhaust turbocharger
Exhaust manifold
EGR cooler
Diesel particulate filter
Flex tube
55
Exhaust Door Control Unit
J883
Baffled rear mufflers
r
608_044
Baffled rear mufler
608_050
56
Exhaust gas treatment
Exhaust emission standards
In vehicles with BIN5 configurations, the Selective Catalytic
Reduction (SCR) system with cylinder pressure sensors in
the glow plugs is also installed. Also, in BIN 5 configuration Engine Coolant Temperature Sensor on Radiator Outlet
G83 is installed.
The chart on this page identifies the various emission
standards that are met with the EA 288 TDI engines on a
world-wide basis. In the United States the EA288 engines
will comply with the BIN5* Tier 2 standard.
Depending on the country applicable exhaust standard,
there are differences between components, both in terms
of type and how the exhaust gases enter the intake system.
Features
EU4
High pressure exhaust recirculation
x
Low pressure exhaust recirculation
Cooled exhaust recirculation valve
EU5
x
x
Uncooled exhaust recirculation valve
x
EU6
EU6 heavy duty
BIN51)/ULEV
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
x
SCR system (AdBlue)
EGR cooler
x
x
x
Additional temperature sensor at radiator
outlet
x
4-way catalytic converter (modified coating on
the monoliths)
x
Cylinder pressure sensor
1
1
4
*The term "BIN" stems from the word "bag". During exhaust emission tests, the exhaust gases are collected in bags and
analyzed. Exhaust emission standards are ranked from BIN10 to BIN5.
57
Exhaust gas recirculation
The BIN5 Tier 2 configuration of the engine uses both high
pressure and low pressure exhaust gas recirculation with a
cooled EGR valve and an EGR cooler. The EGR cooler has a
vacuum controlled by-pass flap actuated by the ECM
depending on operating temperatures.
Upstream of the turbocharger, the recirculated exhaust
gases flow through a port in the cylinder head and into a
water cooled exhaust gas recirculation valve mounted on
the distributor rail.
Distributor rail
The recirculated exhaust gases are divided among the
compressed air and the cooled charge air via the distributor
rail. This air mixture is channeled to the cylinder head
intake port.
The exhaust gas recirculation valve is powered by EGR
Motor V338. It is actuated by the ECM. The quantity of
recirculated exhaust gas is controlled by the stroke of the
valve. To provide protection from the high temperature
exhaust gas, the exhaust gas recirculation valve is cooled by
engine coolant.
EGR Motor V338
Water-cooled EGR valve
608_048
Design of the exhaust gas recirculation (EGR) cooler
Vacuum connection
Vacuum cell
EGR bypass valve
Coolant return line
Uncooled/cooled
exhaust gases to
intake manifold
Exhaust gas inlet
Coolant feed line
Divider plate
608_041
58
Design of the exhaust gas recirculation (EGR) cooler
Transversely mounted engines
Longitudinally mounted engines
EGR
throttle valve
Coolant return line
EGR
throttle valve
EGR Motor V338
EGR Motor V338
Coolant feed line
Cooled exhaust
gases to turbocharger
Cooled exhaust
gases to turbocharger
Exhaust intake from
diesel particulate filter
Coolant feed line
Coolant return line
Exhaust intake from
diesel particulate
filter
59
Divider plate
Condensate outlet
608_040
Exhaust gas treatment module and SCR system
The substrate of the close-coupled exhaust gas treatment
module is made of metal which allows it to reach its
optimum operating temperature more quickly. The metal
body is coated with a substrate of metal oxides including
aluminum oxide with additional layers of platinum and
palladium. These precious metals act as catalysts for hydrocarbons and carbon monoxide.
Integrating the SCR coating into the particulate filter using
copper ziolite enables the system to be positioned close to
the engine. After a cold start, the operating temperature of
the SCR catalyst is reached more rapidly and maintained for
a longer period during low-load vehicle operation.
Reducing Agent Injector N474 is mounted directly downstream of the oxidizing catalytic converter above a transition
funnel to the diesel particulate filter. This allows the entire
volume of the injector to be available for carburetion.
Because of its location, N474 cannot be sufficiently cooled
by air alone. It is has a cooling jacket and is integrated with
the the low temperature circuit of the engine cooling
system.
Design
Exhaust Gas Temperature Sensor 2
G448
Reducing Agent Injector N474
(water cooled)
Exhaust Gas Temperature Sensor 3
G495
Heated Oxygen
Sensor G39
NOx Sensor
G295
Turbocharger
Mixer
Oxidizing catalytic converter
Exhaust Gas Temperatue Sensor 1
G235
Differential Pressure Sensor
G505
Connection for Exhaust Gas Pressure Sensor 1
G450
SCR-coated diesel particulate filter
622_022
60
Ammonia blocking catalyst
An ammonia blocking catalytic converter with a combined
SCR and oxidizing catalyst coating is located downstream
of the SCR-coated diesel particulate filter and performs two
tasks:
Its first task is to oxidize the carbon monoxide (CO) produced during soot regeneration to carbon dioxide (CO2)
through reaction with the precious metal-containing
coating.
Its second task is to ensure that no NH3 leaves the exhaust
system. During this process, NH3 is oxidized to N2 and H2O.
Exhaust gas treatment
module
Reducing Agent Injector N474
(water cooled)
Turbocharger
Exhaust Gas Temperature
Sensor 3 G495
Oxidizing catalytic
converter
Ammonia blocking
catalyst
Exhaust gas recirculation
valve
SCR-coated diesel
particulate filter
Exhaust Door Control Unit
J883
61
625_022
Exhaust Door Control Unit J883
Exhaust Door Control Unit J883 is a throttle valve driven by
an electric motor. It is mounted in the exhaust system in
the direction of flow after the diesel particulate filter. J883
allows exhaust gas recirculation to be regulated. It is
actuated by Engine Control Module J623 via a PWM signal.
Oxidizing catalytic converter
Diesel particulate filter
Exhaust Door Control Unit J883
Flexible tube
Exhaust gas
recirculation
cooler
S514_062
Function
Effects of failure
The task of this module is to generate a slight back pressure downstream of the diesel particulate filter. This produces an excess pressure of approximately 30 – 40 mbar
downstream of the particulate filter relative to the exhaust
pressure downstream of the exhaust flap.
If Exhaust Door Control Unit J883 fails, the valve is moved
to the open position by its return spring. Under these
conditions, no exhaust gas recirculation takes place.
This excess pressure results in a positive purging rate in the
EGR cooler and in the downstream EGR valve. The flow of
re-circulated exhaust gas is controlled (mapped) by the EGR
valve. This back pressure is measured by Exhaust Gas
Sensor 1 G450.
The 73° operating range of the exhaust flap door is defined by:
•
•
•
the exhaust pressure downstream of the exhaust flap
the nominal exhaust pressure upstream of the exhaust flap
the mass flow through the exhaust flap
62
Exhaust gas module mounting
The exhaust gas treatment module is attached to the
engine block and cylinder head at four places. Compensation elements are used because of the normal production
tolerances between different engine configurations. They
ensure the module can be installed without subjecting it to
stress.
s514_054
Function
1
The external thread of the compensation element is a left
hand thread. When the securing bolt is screwed into the
respective attaching point, the bolt turns the compensation
element with it as it turns due to the friction on the
element tabs.
Securing Bolt
Compensation
Element
Because of the left hand thread, the compensation element
turns in the opposite direction to the securing bolt when it
is being inserted into the bracket.
The compensation element moves in the opposite direction
to the bolt head and compensates the play between the
exhaust gas treatment module and the engine.
Tabs
S514_055a
2
Securing Bolt
Compensation
of Play
Compensation
Element
Tabs
s514_101
Reference
The exhaust gas treatment module must be removed and installed in a defined sequence. The compensation
elements must be returned to their optimal position before re-installation and the securing bolts must always
be replaced. Always refer to the latest repair information when performing these procedures.
63
SCR-System
(2015 A3 model shown)
The SCR system has a special reducing agent tank with a
capacity of approximately 17 liters. It is made from high
grade plastic and adapted to the underbody contours of
the particular vehicle.
The tank has its own filler neck and vented filler cap. The
in-tank module of the system has a heater, various sensors,
a pump and a filter. A special anti-sloshing pan and baffle
mat dampen the motion of the reducing agent that occurs
under normal driving conditions.
The in-tank module is firmly attached to the tank. Only the
pump can be replaced if servicing is necessary. All functions
of the SCR system are controlled by the Engine Control
Module.
Overview
Reducing agent filler neck
In-tank module with:
−− Heater
−− Sensors
−− Delivery unit
−− Filter
Service vent
Reducing agent filler tube
Reducing agent tank
Reducing Agent Heater
Control Module J891
Heated metering line to
Reducing Agent Injector
N474
Baffle mat
Reducing Agent Quality Sensor
G849 (on underside of tank)
Diesel
fuel tank
625_020
Reducing Agent Quality Sensor G849
OBD regulations require the installation of a reducing agent
quality sensor in SCR systems. The tank of this sensor is to
detect insufficient reducing agent quality and manipulation.
The sensors are based on ultrasound technology which is
used to measure urea concentration. This measurement
also makes it possible to identify other fluids due to their
different sound velocity characteristics.
64
Ultrasonic channel
Reducing Agent Pump V437 and Reducing
Agent Return Flow Pump V561
In-tank module
In-tank module houses the following components::
• Reducing Agent Tank Heater Z102
• Reducing Agent Reservoir Sensor G697
• Reducing Agent Pump V437
• Reducing Agent Return Flow Pump V561
• Reducing Agent Temperature Sensor G685
Reducing Agent Tank Heater Z102
Because the reducing agent (AdBlue) freezes at approximately 12 °F (-11 °C) the SCR system comes equipped with
a PTC heater. Temperature settings are controlled by
Reducing Agent Heater Control Module J891 in conjunction
with Engine Control Unit J623. In addition, the line to the
externally mounted Reducing Agent Injector N474 is
heated.
625_108
Reducing Agent Temperature
Sensor G685
Reducing agent, AdBlue®
Reducing Agent Tank Heater Z102
(heating circuit 1)
Boundary layer
Air
Reducing Agent Reservoir Sensor G697
G697 is an ultrasound sensor. Ultrasonic waves are guided
through the reducing agent by a special channel to prevent
signal scatter and stray reflection. The waves are reflected
by the boundary layer between the reducing agent and air.
The level is determined by the time difference between the
outgoing and incoming impulses taking into account the
sonic velocity of the reducing agent level.
Reducing Agent Reservoir Sensor G697
In-tank module
625_084
Pulses sent
Pulses reflected
Reducing Agent Pump V437 and Reducing Agent Return
Flow Pump V561 (delivery module)
The delivery module has the following components:
• Twin linear solenoid diaphragm pumps
• A reducing agent supply line to N474
• A line for recirculating the reducing agent after shutting
off the engine
In-tank module
The linear solenoid serves here as a pump drive. The delivery module is mounted separately from the in-tank module
and can be replaced.
Reducing
Agent Pump
V437
To N474
Reducing Agent
Return Flow Pump
V561
625_113
65
Solenoid diaphragm pump
The SCR system on the A3 TDI uses a solenoid driven diaphragm pump to deliver the fluid to the injector instead of
a motor driven pump as seen in the other TDI models. (Q7,
A6, A7, A8, Q5).
The stroke volume is virtually constant and depends only to
a minimal extent on the prevailing pressure. The urea
solution is injected via the reducing agent injector on
demand and depending on the nitrous oxides produced
during the combustion cycle. The quantity of urea solution
injected is then delivered by the reducing agent pump in a
controlled manner. Due to the close tolerances of the
reducing agent pump and reducing agent injector, pressure
equilibrium occurs at approx. 6.5 bar (± 2 bar). This process
of constant volume delivery is also known as volumetric
delivery. There is no need for a pressure sensor, including
the required pressure sensor heater, pressure sensor
housing and control system.
Reducing Agent Recirculating Pump
V561
Tank filter
Linear solenoid
Heater metering line
Pulsation
damper
Screen
filter
Linear solenoid
Reducing Agent Pump
V437
Reducing Agent
injector N474
Engine Control
Module J623
625_085
The pressure in the system can be determined by measuring the time when the pump is first energized to when the
armature in the solenoid moves, as well as by measuring
the amount of electrical current required to move the
solenoid.
During delivery, V437 is energized by ECM J623 using pins
3 and 4. The recirculating pump V561 is energized by J623
using pins 1 & 2. Reducing Agent Recirculating Pump V561
is energized by the ECM using pins 1 and 2.
Large pressure deviations from the normal system pressure
indicate faults in the system; for example, jamming of the
pump, a defective pump diaphragm, a leak in the pressure
line a clogged metering valve, or pump intake problems.
Delivery
Immediately after shutting off the engine, N474 closes and
some of the reducing agent is drawn back out of the metering line by the return flow pump. This is done with N474
closed so no hot exhaust gases are taken in. A short time
later, N474 is opened and additional reducing agent is
drawn back. This process prevents reducing agent from
freezing and creating damage.
Return
Reducing Agent Pump
V437
Linear solenoid
Linear solenoid
Reducing Agent
Recirculating Pump V561
To Reducing Agent Injector
N474
From Reducing Agent
Injector N474
Term. 87 (+)
From tank filter
Ground from J623
To tank filter
Ground fromJ623
Term. 87 (+)
625_138
625_137
66
Special tools and workshop equipment
T10172 with T10172/11 Adapter
T10489 Puller
Adapter for the counterholder of the camshaft
sprocket.
Puller to disassemble
the hub of the highpressure pump.
608_071
608_072
608_064
T10490 Crankshaft stop
T10491 Socket SW22
Crankshaft stop for
holding the crankshaft
when adjusting the
valve timing.
Socket to remove and
install the Oxygen
sensor.
608_068
608_066
T10492 Locking pin
T10493 Assembly tool
Locking pin to lock the
pulley of the highpressure pump.
Tools for installing oil
seals for the camshaft.
608_069
67
608_070
T10497 Engine bracket
T10501 Socket XZN 10
Engine bracket for
removing and installing
the engine in conjunction
with V.A.G. 1383 A
Socket to remove and
install the intake manifold.
S514_070
S514_077
T10511 Assembly aid
T10512 Calibration tool
Assembly aid to remove
and install the exhaust
treatment module.
Calibration tool to adjust
the compensation elements when installing
the exhaust treatment
module.
S514_078
S514_069
68
Knowledge Assessment
An On-Line Knowledge Assessment (exam) is Available for this eSelf-Study Program.
The Knowledge Assessment is required for Certification.
You can find this Knowledge Assessment at:
www.accessaudi.com
From the accessaudi.com Homepage:
•
•
•
Click on the “ACADEMY” tab
Click on the “Academy site” link
Click on the Course Catalog Search and select “920143 - The Audi 2.0L Third Generation TDI Engine”
Please submit any questions or inquiries via the Academy CRC Online Support Form
which is located under the “Support” tab or the “Contact Us” tab of the Academy CRC.
Thank you for reading this eSelf-Study Program and taking the assessment.
69
70
920143
All rights reserved.
Technical specifications are
subject to change without notice.
Audi of America, LLC
2200 Ferdinand Porsche Drive
Herndon, VA 20171
71