Service training Commercial Vehicles
Self-study programme 564
The 2.0 litre TDI engine in the T6 Design and function
The introduction of modern, particularly efficient Euro-6 engines represents a central feature of the new T6. All units are equipped with Blue Motion Technology as standard. Significant consumption and emissions reductions set new best values in the segment. At the same time, the peak power of the TDI engines is now 150 kW (204 PS) and the maximum torque is 450 Nm. On the basis of the modular diesel system s ystem (MDB), the diesel engines in the EA288 series have been developed further for use in commercial vehicles such as the T6. The T6 complies with emission standard EU6 by using new or modified components and functional units.
s564_100
The design and function of the EA288 series of diesel engines with the EU5 emission standard is described in Self-Study Programme 514 “The new diesel engine series EA288”.
Self-Study Programme presents the design and function of new developments! The content will not be updated.
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Current testing, setting and repair instructions can be found in the service literature provided.
Important Note
At a glance
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 The technical features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Engine mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 The cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 The crankshaft group. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 The dual-mass flywheel with centrifugal centrifugal pendulum. . . . . . . . . . . . . . . . . . . . . . 9 The cylinder head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 The camshaft housing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 Cooling system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13 Thermal management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 Oil system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 The oil and vacuum pump. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Air control system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .18 . 18 Forced induction in the 150 kW engine variant . . . . . . . . . . . . . . . . . . . . . . . . 18 Fuel system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20 The injection system with single-plunger high-pressure pump . . . . . . . . . . . . 21 The injection system with dual-plunger high-pressure pump pump . . . . . . . . . . . . . 23 The injectors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 Exhaust post-treatment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27 Overview of the exhaust post-treatment system system . . . . . . . . . . . . . . . . . . . . . . . 27 The diesel particulate filter with SCR trap catalytic catalytic converter . . . . . . . . . . . . . 28 The tank for reducing agent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 Engine management. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 System overview. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Check your knowledge. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38
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Introduction The technical features The 2.0 litre TDI engine is offered for the T6 in four power levels from 62 kW to 75 kW and 110 kW to 150 kW.
The main features as key points - Cylind Cylinder er block block with with and with without out bala balance ncerr shafts shafts - VTG turbo turbocha charge rgerr (62 kW to 110kW) or bi-tu bi-turbo rbo unit (150 kW) - Delp Delphi hi comm common on rail rail syst system em - SCR system - Exten xtende ded d sens sensor orss - Temp Temper erat atur ure e mana manage geme ment nt
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The 2.0 litre TDI engine with 62 kW Torque and power diagram
Technical data Engine code Cubic capacity Design Valves per cylinder Bore Stroke Compression ratio
CXGA
4-cylinder inline engine 4
80
200
60
150
40
100
20
95.5 mm 15.5:1
Max. torque
220 Nm at 1250-2500 rpm Delphi DCM 6.2
Fuel
Diesel acc. to DIN EN 590
Turbocharging
VTG exhaust turbocharger
Emissions standard
250
81 mm
62 kW at 2750-3750 rpm
Exhaust gas recirculation
[kW] 100
1968 cm3
Max. power
Engine management
[Nm] 300
Yes EU6 with diesel particulate filter and SCR system
1000
2000
3000
4000
5000
[rpm]
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The 2.0 litre TDI engine with 75 kW Technical data Engine code Cubic capacity Design Valves per cylinder Bore Stroke Compression ratio
Torque and power diagram CXGB
4-cylinder inline engine 4
80
200
60
150
40
100
20
95.5 mm 15.5:1
Max. torque
250 Nm at 1500-2750 rpm Delphi DCM 6.2
Fuel
Diesel acc. to DIN EN 590
Turbocharging
VTG exhaust turbocharger
Emissions standard
250
81 mm
75 kW at 3000-3750 rpm
Exhaust gas recirculation
[kW] 100
1968 cm3
Max. power
Engine management
[Nm] 300
Yes EU6 with diesel particulate filter and SCR system
1000
2000
3000
4000
5000
[rpm]
s564_048
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Introduction The 2.0 litre TDI engine with 110kW Technical data Engine code Cubic capacity Design Valves per cylinder Bore Stroke Compression ratio
Torque and power diagram CXHA
CXFA
4-cylinder inline engine
120
300
100
250
80
200
60
150
40
81 mm 95.5 mm 15.5:1
Max. torque
340 Nm at 1500-3000 rpm Delphi DCM 6.2
Fuel
Diesel acc. to DIN EN 590
Turbocharging
VTG exhaust turbocharger
Emissions standard
350
4
110 kW at 3250-3750 rpm
Exhaust gas recirculation
[kW]
1968 cm3
Max. power
Engine management
[Nm]
Yes EU6 with diesel particulate filter and SCR system
100
1000 2000 3000 4000 5000 6000 [rpm]
20
9 4 0 _ 4 6 5 s
The 2.0 litre TDI engine with 150 kW Torque and power diagram
Technical data Engine code Cubic capacity Design Valves per cylinder Bore Stroke Compression ratio
81 mm
Emissions standard
140
400
120
350
100
300
80
250
60
95.5 mm 15.5:1
450 Nm at 1400-2400 rpm
Exhaust gas recirculation
450
4
Max. torque
Turbocharging
6
4-cylinder inline engine
150 kW at 4000 rpm
Fuel
[kW]
1968 cm3
Max. power
Engine management
[Nm]
CXEB
Delphi DCM 6.2 Diesel acc. to DIN EN 590 Bi-turbo system Yes EU6 with diesel particulate filter and SCR system
200
1000 2000 3000 4000 5000 6000 [rpm]
40
0 5 0 _ 4 6 5 s
Engine mechanism The cylinder block The cylinder block of the EA288 engine is made from grey cast-iron. This is an alloy of cast iron and lamellar graphite. Both variants are produced with and without balancer shafts. The cylinder block with balancer shafts is fitted in the 2.0 l TDI engine with 150 kW as well as in the 110 kW variant with the engine code CXFA.
Cylinder block without balancer shafts
s564_033 Mountings for the balancer shafts
Cylinder block with balancer shafts
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Engine mechanism The crankshaft group Due to the high mechanical load, a forged crankshaft with five-way bearings is used in the 2.0 l TDI engine. Instead of the usual eight counterweights, this crankshaft has four counterweights for balancing the rotating mass forces. This means the load on the crankshaft bearings is reduced. The toothed belt sprocket for driving the oil pump and the ring gear for driving the balancer shafts are shrink-mounted onto the crankshaft. The pistons have no inlet valve chambers. For cooling the piston ring zone, the pistons have a ring-shaped cooling duct. The conrods are configured as cracked trapezoidal conrods.
Piston with central piston recess
Balancer shaft Ring-shaped cooling duct
Oil inlet/ outlet Oil inlet/ outlet
s564_003a Counterweight Balancer shaft
s564_003 Gear for driving the balancer shafts
For more information about the crankshaft group, refer to Self-Study Programmes 514 “The new diesel engine series EA288” and 547 “The 2.0 l 176 kW TDI bi-turbo engine of the diesel engine series EA288”.
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The dual-mass flywheel with centrifugal pendulum In the dual-mass flywheel (ZMS), the conventional flywheel mass is divided into the primary flywheel mass and the secondary flywheel mass. The primary flywheel mass is connected to the crankshaft. The secondary flywheel mass is connected to the gearbox. The bow spring connects the two flywheel masses as a spring damping system. The centrifugal pendulums are on the secondary side in the dual-mass flywheel, attached after the bow springs. This means the necessary mass of the pendulums for damping is lower than on the primary side.
The dual-mass flywheel with centrifugal pendulum
s564_034 Bow spring
Centrifugal pendulum
s564_035 Primary flywheel mass
Secondary flywheel mass
For more information about the dual-mass flywheel with centrifugal pendulum, please refer to Self-Study Programme 542 “The Passat 2015”.
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Engine mechanism
Installation variants Two different dual-mass flywheels from different manufacturers are used in the T6.
The dual-mass flywheel from ZF is fitted in the T6 with the 2.0 l 150 kW TDI engine in conjunction with the dual clutch gearbox. The maximum torque that can be transmitted is 500 Nm.
Centrifugal pendulum
The secondary flywheel mass of this installation variant has penetrations, which means that the centrifugal pendulum can be seen from the outside through the penetrations. This dual-mass flywheel has 6 centrifugal pendulums that are mounted between the flange and secondary mass on floating bearings.
s563_052 Centrifugal pendulum visible through the secondary flywheel mass
The dual-mass flywheel from LUK is used in all other engine variants of the T6. The maximum torque that can be transmitted is 450 Nm.
Flange
Secondary flywheel mass
Centrifugal pendulum
The centrifugal pendulums of this installation variant are covered by the secondary flywheel mass, and cannot be seen from the outside. This dual-mass flywheel has 4 centrifugal pendulums that are mounted in floating bearings directly on the flange.
s563_051 Secondary flywheel mass
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The cylinder head The cylinder head is manufactured from an aluminium alloy. Four valves a re fitted per cylinder. The valve arrangement is the classic design, i.e. the inlet valves are on the inlet side and the exhaust valves on the exhaust side. The valve is actuated using roller rocker fingers with compensation elements. The combustion chamber pressure sender for cylinder 3 G679 is integrated in the glow plug for this cylinder, and is screwed into the cylinder head like the other glow plugs.
Roller rocker finger with compensation element Outlet openings (shown in red)
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Inlet openings (shown in blue)
Outlet valve
Inlet valve
Cylinder head housing
For more information about the function of the combustion chamber pressure sender, refer to the “Engine management” chapter.
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Engine mechanism The camshaft housing The inlet and exhaust camshafts are integrated together in one camshaft housing. The exhaust camshaft is driven by the toothed belt drive. The inlet camshaft is driven via spur gearing by the exhaust camshaft. The sender wheel for the Hall sender G40 is located on the inlet camshaft. The Hall sender itself is inserted in the cylinder head cover.
Sender wheel for Hall sender G40
Intake camshaft s564_031
Exhaust camshaft
Camshaft housing
Spur gearing
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Cooling system Thermal management The coolant circuit is made up of two subcircuits: - the high-temperature circuit - the low-temperature circuit
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Legend 1 Main cooler Exhaust gas recirculation cooler 2 3 Heat exchanger for heater Engine oil cooler 4 Gear oil cooler 5 6 Coolant pump 7 Low-temperature radiator 8 Charge air cooler 9 Injector for reducing agent N474 10 2/3-way valve (thermostatic 65 - 75 °C)
11 12 13 14 15 16
Coolant pump for high-temperature circuit V467 Charge air cooling pump V188 Non-return valve Coolant thermostat Pump for cooler of exhaust gas recirculation V400 2/3-way bleeder valve (thermostatic)
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Cooling system
High-temperature circuit
s564_018
When the engine is cold, coolant circulates from the coolant pump (6) through the oil cooler (4), the cylinder head, the cylinder block and the heat exchanger for heater (3) The 2/3-way bleeder valve (16) is opened. It closes at a coolant temperature of 49 °C. When the engine has reached operating temperature, the coolant thermostat (13) opens at 92 °C. The coolant pump for high-temperature circuit V467 (11) is activated according to the heating requirement and the coolant temperature. The heating requirement is registered by the control unit of the air conditioning system. Activation is performed by the engine control unit. The pump for the exhaust gas recirculation cooler V400 (15) is activated after the ignition is switched on with a delivery rates of 70% by a PWM signal from the engine control unit. It runs permanently across all operating ranges. Activation is increased to 100% delivery rates if there is a higher EGR cooling requirement.
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Low-temperature cooling circuit
s564_019
The liquid-cooled charge air cooling makes it possible for the air temperature in the intake manifold to be controlled at a nominal value according to requirements. The charge air temperature is controlled by the engine control unit activating the charge air cooling pump V188 (12). The guidance parameter for activation is the intake manifold temperature after the charge air cooler. The coolant circuit for charge air cooling is connected to the engine cooling circuit via a non-return valve and a throttle for filling and venting. There is no connection to the engine cooling circuit during operation. The injector for reducing agent N474 (9) is integrated in the low-temperature cooling circuit.
In order to flush out possible air bubbles after filling, a bleeder process must be carried out with the tester. This involves activating the electric coolant pumps in various combinations. Activation is first without the engine running, and then at specified engine speeds.
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Oil system The oil and vacuum pump
Drive via the crankshaft
Cylinder block
Oil pump Vacuum pump
s564_039
Installation location and drive The oil pump and the vacuum pump are integrated together in one housing. The pump housing is bolted onto the underside of the cylinder block. The pumps have a common drive shaft and are driven via a toothed belt by the crankshaft. The maintenance-free toothed belt runs directly in the oil and is exclusively tensioned by the centre distance between the toothed belt pulleys. A riser pipe in the cylinder block (oil supply) carries the oil from the oil pump to the oil pressure control valve N428. The vacuum pump is connected via a hole in the cylinder block to a connection for the vacuum line that leads to the engine vacuum system.
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Structure Flutter valves
Housing cover
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Housing
Vacuum pump Control piston Non-return valve Vane pump Input gear with housing cover
Oil pump The oil pump is a vane pump controlled by the flow rate in which the pumping characteristics of the pump can be changed by an adjusting ring in an eccentric mounting. The position of the rotating adjusting ring changes the delivery volume of the pump, and thus the drive power of the pump is adapted to the operating conditions of the engine.
Vacuum pump The vacuum pump draws air from the brake servo as well as from the vacuum system of the engine through vacuum lines, and directs it through the flutter valves into the cylinder block. The drawn-in air then flows through the crankcase breather as blow-by gas into the intake manifold, and is supplied to the combustion process. The oil used for lubricating the vacuum pump passes through the flutter valve out of the working space of the vacuum pump into the oil pan.
For more detailed information about the oil system of the EA288 engine series, refer to the Self-Study Programme 514 “The new diesel engine series EA288”.
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Air control system Forced induction in the 150 kW engine variant In the 2.0 l TDI engine with 150 kW, two turbochargers connected in series generate the charge pressure, and together form a bi-turbo unit. The intake air is pre-compressed by the low-pressure turbocharger at low engine speeds, with the main compression being performed by the high-pressure turbocharger (two-stage operation). At high engine speeds, the low-pressure turbocharger compresses the intake air alone (one-stage operation).
Compressor bypass valve
Vacuum unit for guide vane adjustment High-pressure turbocharger with adjustable guide vanes
Exhaust manifold
s564_005 Low-pressure exhaust turbocharger
Vacuum unit for exhaust flap Vacuum unit for wastegate flap
Special features of the turbocharger system with bi-turbo unit: - High-pressure turbocharger with adjustable guide vanes, small turbine and small compressor wheel. This means a fast response is achieved at low engine speeds. - Low-pressure turbocharger with large turbine wheel and large compressor wheel. This achieves a high charge pressure at high engine speeds. As a result, a high engine power is achieved at high engine speed. - Compact design: The high and low-pressure turbochargers are directly mounted on the exhaust manifold.
The other power variants of the 2.0 l TDI engine in the T6 use a turbocharger system with an individual VTG turbocharger.
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Overview of the charge air system
s564_020
Legend Air filter 1 2 Air mass meter G70 3 Compressor wheel of the low-pressure turbocharger Charge pressure sender 2 G447 4 Compressor wheel of the high-pressure 5 turbocharger 6 Compressor bypass valve 7 Throttle valve module GX3 Charge pressure sender G31 8 Intake air temperature sender G42 9 10 Charge air cooler 11 Charge air temperature sender after charge air cooler G811 12 Control motor for exhaust gas recirculation GX5
13 14 15 16 17 18 19 20
21 22 23 24
Exhaust gas recirculation cooler Exhaust gas temperature sender 1 G235 Turbine bypass flap Vacuum unit for exhaust flap with position sender 2 for charge pressure positioner G580 Valve for turbine changeover N259 Turbine of the high-pressure turbocharger Charge pressure control solenoid valve N75 Vacuum unit for guide vane adjustment with position sender for charge pressure positioner G581 Wastegate flap Vacuum unit for wastegate flap Solenoid valve 2 for charge pressure control N274 Turbine of the low-pressure turbocharger
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Fuel system Depending on the power variant, the 2.0 l TDI engine in the T6 has two different fuel systems: - Injection system with single-plunger high-pressure pump in the 62 kW, 75 kW and 110 kW variants - Injection system with dual-plunger high-pressure pump in the 150 kW variant
Injection system with single-plunger highpressure pump
Injection system with dual-plunger highpressure pump
s564_032
Both systems are manufactured by Delphi. In addition to the configuration of the high-pressure pump, they also differ with regard to the version of the high-pressure accumulator (rail), the number of high-pressure lines and the size of bore in the injectors used.
When renewing the injectors, make sure that you use the injectors specified for the particular power variant in ELSA. The various injectors only differ in their bore diameter, and from the outside they can only be distinguished by means of the part number.
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The injection system with single-plunger high-pressure pump Overview
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Legend Fuel pump 1 Fuel tank 2 3 Fuel filter 4 Single-plunger high-pressure pump 5 Fuel temperature sender G81 6 Fuel pressure sender G247 7 Fuel rail (high-pressure accumulator) Fuel pressure regulating valve N276 8 Injectors N30, N31, N32, N33 9 Fuel metering valve N290 10
Fuel high pressure up to 2000 bar Fuel supply pressure 4.0-6.0 bar Fuel return pressure from the injectors 4.0-6.0 bar Fuel return pressure 0 -0.3 bar
Special features - High-pressure pump with single plunger and one high-pressure outlet - One fuel high-pressure line between the pump and high-pressure accumulator - High-pressure accumulator with one high-pressure connection - 8-hole injectors with 700 ml
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Fuel system
Fuel system in detail Single-plunger high-pressure pump The high-pressure pump is operated via the ancillary drive. The pressure piston is actuated by a plunger mounted in a roller. The fuel metering valve N290 is integrated in the high-pressure pump. The compressed fuel is carried along a high-pressure line at a pressure of up to 2000 bar to the high-pressure accumulator. The pump capacity is maximum 0.42 cm3/rev.
Fuel metering valve N290
Driven axle
Return
Supply
High-pressure connection to high-pressure accumulator s564_007
High-pressure accumulator The high-pressure accumulator has a volume of 12.3 cm3. It is connected to the high-pressure pump via a high-pressure line, and is somewhat shorter than the high-pressure accumulator of the dual-plunger high-pressure pump. The fuel pressure regulating valve N276 and the fuel pressure sender G247 are screwed into the high-pressure accumulator.
Regulating valve for fuel pressure N276 High-pressure connectors to the injectors Return
High-pressure accumulator
s564_009
High-pressure connection to single-plunger high-pressure pump
Fuel pressure sender G247
For more information about the single-plunger high-pressure pump, please refer to Self-Study Programme 465 “The 1.2 l 3-cylinder TDI engine with common rail Injection system” .
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The injection system with dual-plunger high-pressure pump Overview
s564_021
Legend 1 Fuel pump Fuel tank 2 Fuel filter 3 Dual-plunger high-pressure pump 4 5 Fuel temperature sender G81 6 Fuel pressure sender G247 7 Fuel rail (high-pressure accumulator) 8 Fuel pressure regulating valve N276 Injectors N30, N31, N32, N33 9 Fuel metering valve N290 10
Fuel high pressure up to 2000 bar Fuel supply pressure 4.0-6.0 bar Fuel return pressure from the injectors 4.0-6.0 bar Fuel return pressure 0 -0.3 bar
Special features - Dual-plunger high-pressure pump with two high-pressure outlets - Two fuel high-pressure lines between the pump and high-pressure accumulator - High-pressure accumulator with two high-pressure connections - 8-hole injectors with 900 ml
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Fuel system
Fuel system in detail Dual-plunger high-pressure pump This high-pressure pump is also operated via the ancillary drive. In this case, in contrast to the single-plunger high-pressure pump, the pressure piston is actuated by a slide.
Fuel metering valve N290
High-pressure connection to highpressure accumulator
Driven axle
The fuel metering valve N290 is integrated in the high-pressure pump. The compressed fuel is carried along a high-pressure line at a pressure of up to 2000 bar to the high-pressure accumulator. The pump capacity is maximum 0.7 cm3/rev.
Supply Return s564_008 High-pressure connection to high-pressure accumulator
High-pressure accumulator The high-pressure accumulator has a volume of 18 cm3. It is connected to the high-pressure pump via two high-pressure lines, and is somewhat longer than the high-pressure accumulator of the single-plunger high-pressure pump. In this case too, the fuel pressure regulating valve N276 and the fuel pressure sender G247 are screwed into the high-pressure accumulator.
Regulating valve for fuel pressure N276 High-pressure connectors to the injectors Return
High-pressure accumulator
s564_010
High-pressure connections to dual-plunger high-pressure pump
Fuel pressure sender G247
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The injectors The injectors in both fuel systems differ only with regard to the bore diameter of the injection ducts. Structure and mode of function are identical.
Structure and function
20-digit correction value on the head
Connection to the high-pressure accumulator (rail) s564_055 Connection to the fuel return Electrical connection
Solenoid coil Valve spring
There is a data carrier on the head of the injectors. This data carrier has a 20-digit correction value for the injectors imprinted on it. The correction value is ascertained during production for each injector on a test bench. It describes the injection properties of this precise injector. The injectors are attached in the cylinder head using clamping claws. Their task is to inject the correct quantity of fuel into the combustion chambers at the right time. For this purpose, they are activated by the engine control unit. If the solenoid valve is not activated, the pressure conditions at the nozzle needle and in the control space are the same. The injector remains closed. When the solenoid valve is activated, the valve opens the fuel return and the pressure in the control space is dissipated. Now, the injection starts. The solenoid coil is not activated to finish the injection. The valve closes the return, the pressure in the control space rises and the nozzle needle closes with the help of the nozzle needle spring.
Valve Nozzle needle spring
Nozzle needle s564_053
For more information about the injectors, refer to Self-Study Programme 465 “The 1.2 l 3-cylinder TDI engine with common rail injection system”.
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Fuel system
Activation phases It is necessary for the correction value on the head of the injector to be entered in the engine control unit so that the activation of this injector can be individually controlled within the entire characteristic map, and corrected across the full correction range. This permits precise control of the injection quantities. It contributes to reducing fuel consumption and exhaust emissions as well as allowing the engine to run more smoothly. The signals from the two knock sensors are one of the main measuring parameters.
[A] Control current
[µs] s564_056
Valve open and nozzle needle open
Valve open and nozzle needle closed
Valve closed and nozzle needle closed
s564_057
s564_059
s564_061
Valve
Valve
Valve
Nozzle needle
Nozzle needle
Nozzle needle
s564_058
The solenoid valve is activated. The control current increases to approx. 23 A with a voltage of 12 V. The injector still remains closed during this phase.
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Characteristic map of the activation phases
s564_060
The valve lifts out of its seat. The control current is regulated at the holding current of approx. 9 A. In this phase, the nozzle needle also starts to lift.
s564_062
The nozzle needle is open and injection takes place. The injection quantity is determined by the time duration of activation.
Exhaust gas post-treatment Overview of the exhaust post-treatment system The structure of the exhaust post-treatment is identical for all output stages of the 2.0 l TDI engine in the T6. The oxidation catalytic converter is connected to the particular turbocharger system. The diesel particulate filter with SCR trap catalytic converter is connected as a module with a corrugated tube as the transition. The injector for reducing agent N474 is installed in this module. In addition to the exhaust gas temperature sensors (G235, G448, G495, G648) and the NOx sender (G687), a new sensor is fitted after the SCR trap catalytic converter for registering the soot particle emissions (particulate sensor G784). The injector for reducing agent is supplied with reducing agent (AdBlue) from the tank for reducing agent by means of the reducing agent pump unit (GX19). The tank for reducing agent has a capacity of approx. 13 litres. The range is approx. 5200 km. In addition to a fill level sensor, the delivery pump and the heater, the pump module also contains a quality sensor for monitoring the quality of the reducing agent (sensor for reducing agent quality G849).
Bi-turbo unit Oxidation catalytic converter Corrugated tube Reducing agent tank
Injector for reducing agent
Particulate sensor Silencer
Diesel particulate filter with SCR trap catalytic converter NOx sensor
Rear silencer s564_011
The precise function of the particulate sensor G784 and the sensor for reducing agent quality G849 in the tank for reducing agent is described in the Engine management chapter.
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Exhaust gas post-treatment The diesel particulate filter with SCR trap catalytic converter
Corrugated tube
Injector for reducing agent
Particulate sensor s564_012 Diesel particulate filter SCR trap catalytic converter Exhaust temperature sender NOx sender
Silencer
Structure and function The diesel particulate filter and SCR trap catalytic converter are combined into one module. The SCR system (Selective Catalytic Reduction) is used in the T6 to achieve the EU6 emissions limits. This means that in this part of the exhaust post-treatment, only the nitrogen oxides (NOx) specifically are reduced amongst the exhaust gas constituents. These are converted in the SCR trap catalytic converter (SCR catalytic converter) into nitrogen (N 2) and water (H2O). For this purpose, a reducing agent (AdBlue) is continuously injected into the exhaust gas stream via the injector for reducing agent; this injector is cooled by means of coolant. The injector is installed at the front in the module comprising the diesel particulate filter and SCR trap catalytic converter.
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Injector for reducing agent Installation location and task The injector for reducing agent N474 is installed in front of the module comprising the diesel particulate filter and SCR trap catalytic converter. It is integrated in the low-temperature coolant circuit of the thermal management system, and its task is to inject a dosed amount of reducing agent into the exhaust gas stream after the oxidising catalytic converter.
Injector for reducing agent s564_043
Reducing agent line connection
Electrical connection Solenoid valve
Cooling connections
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Structure and function The injector for reducing agent is a solenoid valve. It is activated by the engine control unit with a pulse-width modulated signal. The required quantity of reducing agent is calculated by a calculation model in the engine control unit that is based on a theoretical nitrous oxide proportion in the exhaust gas mass flow. To calculate the nitrous oxide proportion in the exhaust gas, the signals from the temperature sensors are evaluated as well as those from the pressure sensors, the masses of the drawn-in air, the recirculated exhaust gases and the injected fuel. The coolant jacket not only protects the mechanical components but also the electrical connection of the valve against overheating.
For more information about the injector for reducing agent, refer to Self-Study Programme 540 “The selective catalytic reduction exhaust post-treatment system in the Passat 2015”.
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Exhaust gas post-treatment The tank for reducing agent Control unit for reducing agent heating J891 Reducing agent tank Filling pipe
Pump unit for reducing agent dosing system GX19
Sensor for reducing agent quality G849
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Structure and function The tank for reducing agent is made of plastic. Its capacity is approx. 13 litres. It is fitted under the vehicle floor in the vicinity of the driver's seat. The filling connection is located under the fuel filler pipe behind the tank flap. The pump unit for reducing agent glazing system GX19 is firmly integrated into the tank and cannot be individually renewed. The pump for reducing agent V437 represents an exception to this. The sensor for reducing agent quality G849 is new in the T6.
The precise function of the sensor for reducing agent qu ality in the tank for reducing agent is described in the Engine management chapter.
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The pump unit for the reducing agent dosing system Installation location and task The following components are integrated in the pump unit for reducing agent dosing system GX19: - Pump for reducing agent V437 - Tank sensor for reducing agent G684 - Heater for tank for reducing agent Z102 - Reducing agent temperature sender G685
Pump for reducing agent V437
Heater for tank for reducing agent Z102 Connection Reducing agent line
Electrical connection
Temperature sender for reducing agent G685 s564_046
Tank sensor for reducing agent G684
For more information about the pump unit for reducing agent dosing system GX19, refer to Self-Study Programme 540 “The selective catalytic reduction exhaust post-treatment system in the Passat 2015”.
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Engine management System overview Sensors Engine speed sender G28 Hall sender G40 Air mass meter G70
Heater for reducing agent line (heating circuit 2) Z104
Coolant temperature sender G62 and coolant temperature sender 3 G812 Coolant temperature sender at radiator outlet G83 Charge pressure sender G31 and charge pressure sender 2 G447
Heater for reducing agent tank (heating circuit 1) Z102
Charge higher temperature sender before and after charge air cooler G810 and G811 Fuel temperature sender G81 Fuel pressure sender G247 Exhaust gas recirculation valve 1 GX5 Lambda probe 1 before catalytic converter GX10 Exhaust gas temperature sender 1-4 G235, G448, G495, G648
Control unit for reducing agent heating J891
Control unit for NOx sender 2 J881 with NOx sender 2 G687
Pressure differential sender G505 Temperature sender 2 and 3 for exhaust gas recirculation G690 and G949 Intake manifold sender GX9
Control unit for sensor electronics J849 with particulate sensor G784
Sender for variable intake manifold position G513 Throttle valve module GX3 CAN data bus Drive
Knock sensor 1 and 2 G61 and G66 Position sender for charge pressure positioner G581 and position sender 2 for charge pressure positioner G580 Sensor for reducing agent quality G849 Pump unit for reducing agent dosing system GX19 Tank sender for reducing agent G684 Reduction agent temperature sender G685 Gearbox neutral position sender G701
Combustion chamber pressure sender for cylinder 3 G679 Accelerator pedal module GX2 Brake light switch F
Oil pressure switch for reduced oil pressure F378 Oil level and oil temperature sender G266 Oil pressure switch F1
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Clutch position sender G476
ctuators Warning lamp for pre-glow time K29 Exhaust emissions warning lamp K83 Warning lamp for diesel particulate filter K231
Fuel pump control unit J538 Fuel delivery unit GX1 Fuel system pressurisation pump G6 Injectors for cylinders 1-4 N30, N31, N32, N33 Fuel metering valve N290 Control valve for fuel pressure N276 Charge pressure control solenoid valve N75
Control unit in dash panel insert J285
Charge pressure control solenoid valve 2 N274
Injector for reducing agent N474 CAN data bus Comfort Throttle valve module GX3 Diagnostic interface for data bus J533
Exhaust gas recirculation valve 1 GX5
Exhaust gas recirculation cooler change-over valve N345 Valve 1 for camshaft adjustment N205 Diagnostic connector
Pump for exhaust gas recirculation cooler V400 Charge air cooling pump V188 Coolant pump for high-temperature circuit V467 Oil pressure control valve N428
Engine control unit J623
Lambda probe 1 before catalytic converter GX10 Heater element for crankcase breather N79
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Control unit for automatic glow timer J179 Glow plugs 1-4 Q10, Q11, Q12, Q13
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Engine management Sensors Various innovative sensors are used in the 2.0 l TDI engine in the T6. Their structure and mode of function are described below.
Combustion chamber pressure sender for cylinder 3 G679 Installation location and structure The combustion chamber pressure sender is integrated in the glow plug of the third cylinder. Advantages of cylinder pressure-controlled combustion regulation: - Precise control of the injection timing and quantity - Adaptation of the injection quantity tolerances of the injectors over the operating time - More stable and smoother engine running across all cylinders - Adaptation of the injection under cylinder distortion due to high exhaust gas recirculation rates and different fuel qualities
s564_029 Combustion chamber pressure sender for cylinder 3 G679
Mode of function The measuring principle of the combustion chamber pressure sender for cylinder 3 G679 is based on a heating rod that can move in an axial direction, and transfers the combustion pressure in the cylinder to a measuring diaphragm. Strain gauges are installed on this measuring diaphragm which change their electrical resistance under deformation. Integrated evaluation electronics use the resistance valve to calculate an analogue voltage signal in proportion to the measured cylinder pressure, which is sent to the engine control unit.
Combustion chamber pressure sender in the glow plug
s564_040 Strain gauge
Resistance
Measuring diaphragm
Heating rod
pcombustion chamber
pcombustion chamber Resistance
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Sensor for reducing agent quality G849 Installation location and task s564_013
The reducing agent quality sensor is inserted into the reducing agent tank from underneath. It monitors the reducing agent concentration. If the sensor detects that the urea concentration is falling or inadequate, for example because the tank has been filled up with water, a warning message is output via the engine control unit.
Reducing agent tank Sensor for reducing agent quality
Structure and function
Ultrasound pulse Reducing agent (urea) Sound source/receiver
Reflector
tNOM - tACT = 0 >> concUREA = OK
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tNOM - tACT ≠ 0 >> concUREA = not OK
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Simply put, the sensor consists of an ultrasound source with an ultrasound receiver and a reflector. When the sound source triggers an ultrasound pulse, this requires a particular time to travel to the reflector and back to the receiver. The time taken by the pulse depends on the density of the medium through which it passes. The medium is the reducing agent. Its density depends on the urea concentration (concUREA). As a result, the time taken by the ultrasound pulse to travel through the original reducing agent is different from when it travels through a diluted reducing agent. The travel time value for the undiluted, original reducing agent is stored in the centre electronics as a reference value (nominal value t NOM). This is compared with the currently measured travel time value (actual value tACT). If a difference is measured between the nominal and actual values, the sensor electronics evaluate this and send the result to the engine control unit as a quality signal.
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Engine management
Particulate sensor G784 Installation location and task Sensor electronics
The particulate sensor consists of the sensor itself and the sensor electronics. Both are spatially separated from one another, and are connected together using a fixed line. The sensor is screwed into the exhaust pipe after the diesel particulate filter, as the last sensor in the system. The sensor electronics are screwed onto the floor panel from underneath. The task of the particulate sensor is to monitor the mass of soot particles remaining after the diesel particulate filter. If an excessive particulate mass is measured at the end of the exhaust system, the engine control unit activates the warning light for the diesel particulate filter. The system must be checked.
Sensor
NOx sensor Exhaust temperature sender Diesel particulate filter with SCR trap catalytic converter
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Structure and function The sensor contains a ceramic substrate onto which two intermeshing conductor paths are applied. The two conductor paths do not touch one another. There is a potential difference (voltage, U) between the conductor path, which causes an electrical field to form. If there are no soot particles, no current (I) flows between the conductor paths. This means there is a measurable, high electrical resistance (R). Soot particles are electrically conductive because of the carbon they contain, which means that a current begins to flow when soot particles are deposited on the ceramic substrate as soon as they enter the electrical field between the two conductor paths. This causes the electrical resistance between the conductor paths to decrease.
Ceramic substrate
Conductor paths
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The intensity of the current that can be measured, or the level of electrical resistance, can thus be used as a measure of the soot particle emissions.
Soot particles
When an exhaust system is functioning correctly, only a few soot particles will be deposited on the ceramic substrate of the sensor. This means only a small current will flow between the international conductor paths given a constant sensor voltage, and the sensor electronics measure a high electrical resistance.
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If the diesel particulate filter is defective, it allows more soot particles to pass through it. As a result, more particles can be deposited on the ceramic substrate, and a larger current flows. The sensor electronics now measure a lower resistance. If the resistance value falls below a predetermined limit, this triggers the engine control unit to activate the warning light for the diesel particulate filter and to store an entry in the fault memory. The ceramic surface of the sensor is periodically cleaned by burning off.
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Test your knowledge Which answer is correct? One or more of the model answers could be correct.
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1.
How many counterweights does the crankshaft have in the 2.0 l TDI engine?
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a) 4
❒
b) 6
❒
c) 8
2.
What are the names of the two subcircuits in the cooling system?
3.
What is the function of the particulate matter sensor?
❒
a) It measures the weight of the soot particles.
❒
b) It monitors the function of the diesel particulate filter.
❒
c) It supplies information to the engine control unit about when a regeneration of the diesel particulate filter is required.
4.
What is the sensor for the reducing agent quality for?
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a) It detects that only genuine reducing agent from Volkswagen is being used.
❒
b) It monitors the concentration of reducing agent (urea) in the reducing fluid.
❒
c) It detects if the SCR tank is overfilled.
5.
How is a rapid response of the biturbo engine achieved at low engine speeds?
❒
a) By having a small turbine and a small compressor wheel in the high pressure turbocharger.
❒
b) By having a large turbine and a large compressor wheel in the high pressure turbocharger.
❒
c) The turbocharger switches to single-stage operation.
6.
How have the flywheel masses been reduced?
❒
a) The centrifugal pendulums are only on the primary side.
❒
a) The centrifugal pendulums are only on the secondary side.
❒
c) The centrifugal pendulums are distributed between the primary and secondary sides.
) b . 6 ; ) a . 5 ; ) b . 4 ; ) b . 3 ; t i u c r i c e r u t a r e p m e t - w o l , t i u c r i c e r u t a r e p m e t - h g i H . 2 ; ) a . 1 : s n o i t u l o S
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