Service Training
Self-study Programme 465
The 1.2l 3-cylinder TDI engine with common rail fuel f uel injection system system . Volksw age n n AG
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Reduced to the maximum The 1.2l TDI engine with common rail injection system has joined the new generation of efficient, economic and dynamic diesel engines from Volkswagen. Volkswagen. This new three-cylinder diesel engine was developed on the basis of the 1.6l TDI four-cylinder fou r-cylinder diesel engine introduced in early 2009 and replaces the successful 1.4l TDI engine with unit injector system. The new 1.2l TDI engine not only meets the growing demand for dynamics and comfort in an ideal way, it also boasts extremely low consumption and pollutant emissions. n AG a g e
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t g Thanks to this engine, the o Polo Po lo u a Blue Motion scores top r a n t e marks with a minimal fuel consumption of 3.3l/100km e o r a c and CO2 emissions of 87g/km. c e p
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S465_002
The self-study programme portrays the design and function of new developments. The contents will not be updated.
2
For current testing, adjustment and repair instructions, refer to t he relevant service literature.
Important Note
Reduced to the maximum The 1.2l TDI engine with common rail injection system has joined the new generation of efficient, economic and dynamic diesel engines from Volkswagen. Volkswagen. This new three-cylinder diesel engine was developed on the basis of the 1.6l TDI four-cylinder fou r-cylinder diesel engine introduced in early 2009 and replaces the successful 1.4l TDI engine with unit injector system. The new 1.2l TDI engine not only meets the growing demand for dynamics and comfort in an ideal way, it also boasts extremely low consumption and pollutant emissions. n AG a g e
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S465_002
The self-study programme portrays the design and function of new developments. The contents will not be updated.
2
For current testing, adjustment and repair instructions, refer to t he relevant service literature.
Important Note
Contents Introduction Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 The 1.2l 55kW 55kW TDI engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
Engine Components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Cylinder block . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Crankshaft Crankshaft . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 Cylinder head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Cylinder head cover . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Balancer shaft module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 Toothed belt drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Ancillary component drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Oil system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Oil pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Oil sump . . . . . . . . . . .G. . V . . l.k . . .g . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 A AG d g w s Coolant circuit circuit . . . . . . . . . . . . . . . . . . .o o.e . n .o t . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12 l k o V g u b y a r Low-temperatur Low-temperature e exhaust gas recirculation rec irculation . a . n .t . . . . . . . . . . . . . . . . . . . . . . . . . 13 e d s i r o h t u Intake flaps . . . . . . . . . . . . . o .r a . . . . . . . . . . . . . . . . . . . . . . . 14 a manifolds with swirl flaps s s e system l Fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . e p . t a . . . . . . . . . . . . . . . . . . . . 16 n system u d The common common rail fuel injection injection system . . . . . . . . . . . . .n y .i a . . . . . . . . . . . . . . . . . 20 a
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Engine Management Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . System System overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . w Engine control control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Turbocharger urbocharger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . i , Throttle Throttle valve module module J338 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Exhaust gas recirculation recirculation system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Diesel particulate filter system system . . . . . . . . . . . . . . . . . . . . . . . . r . o. . . . . . . . . . . . . m system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . a. . . . . . . . . . . . . . m Glow plug system o m Start/stop system system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . n . n. . . . . . . . . . . . . . . ,
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Test Yourself Yourself . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
3
Introduction
1.2l 55kW TDI engine A new 3-cylinder engine has been b een developed developed in the t he form of the 1.2l 55kW TDI engine. It is based on t he 1.6l TDI engine introduced at the beginning of 2009. This engine design d esign is a prime example of “down-sizing”. down-sizing”. Down-sizing refers to a reduction in the displacement of an engine without changing the output or the torque. torque . The displacement can be reduced by reducing the displacement of each cylinder, reducing reducing the number of cylinders cy linders or a combination of both. This reduces the weight and the internal friction of the engine and thus the fuel consumption. Volksw a
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c c a new common rail injection In addition to the weight and friction-reducing friction-reducing measures, this engine is equipped with e p t u a n pressure and precise system that contributes to e dreducing harmful ha rmful emissions by using a high maximum injection y t i a b m control. r i t i
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Thanks to the new 1.2l 55kW TDI engine and fu rther measures like aerodynamic aerodynamic modificationse to the front, sides, e s l p o e the Polo Blue floor and rear end, en h d, the start/stop s tart/stop system and low rolling resistance tires mounted on alloy rims, w o Motion scores top n marks with a low fuel consumption of 3.3l/100km and CO 2 emissions of 87g/km. s
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S465_025
The design and function of the 1.6l TDI engine are described in self-study programme programme no. 442 4 42 “1.6ltr. “1.6ltr. TDI engine with common rail injection system”. s ystem”.
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Technical features Common rail fuel injection system s ystem with solenoid valve-controlled injectors Adjustable t urbocharger urbocharger Exhaust gas recirculation module consisting of an exhaust exhaus t gas recirculation valve and switchable exhaust gas recirculation recirculation cooler Oxidising catalytic converter Balancer shaft module
Technical data Engine code
C FWA
Typ e
3- cylinder in-l ine e ngine
Displaceme nt
1,1 99cm3
Bore
7 9.5mm
Stroke
80.5mm
Valve s p er cyl inde r
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Maximum torque
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Fuel
55kW at 4,200rpm 180Nm at 2,000 rpm
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Exha ust gas recirculation, oxidising catal ytic converter, diesel particulate filter
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S465_024 Engine speed (rpm)
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Engine Components G e n A a g
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Cylinder block
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The cylinder block of the 1.2l TDI engine s sis basically e l the same as the cylinder block of the d u n 1.6l TDI engine e t with common rail injection system. m r e p Since the 1.2l TDI engine has one t less cylinder, the o n cylinder block is accordingly shorter and lighter.
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w The cylinder diameter is 79.5mm and the stroke is n 80.5mm. This almost square ostroke/bore ratio leads to low friction losses on the cylinder liners. i , This measure is used to reduce the internal friction o of the engine and contributes p to the low fuel u p consumption.
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S465_031
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Crankshaft
Counterweights
The rotating moments of inertia of the engine are balanced by the counterweights on the crank webs of cylinders 1 and 3. The two outer crank webs (weights) have larger dimensions than the two inner crank webs. The larger lever arm of the outer weights in relation to the centre of gravity of the crankshaft distributes the mass perfectly to balance the forces. S465_033
Counterweights
Drive sprocket for balancer shaft module
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Cylinder head Spur gear teeth
The cylinder head of the 1.2l TDI engine is made from cast aluminium and has two inlet and two exhaust valves on each cylinder. The valves are arranged according to the principle of cross-flow.
Roller rocker fingers Inlet camshaft
The camshafts are driven by the crankshaft via a toothed belt and the exhaust camshaft gear wheel. The intake and exhaust camshafts are linked via meshed spur gears with integrated backlash compensation. The valves are actuated by low-friction roller rocker fingers with hydraulic valve play compensation. Exhaust channels
Exhaust camshaft
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Pressure regulating valve for crankcase ventilation system
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Vacuum reservoir
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The oil filler neck, the crankcase ventilation system, o the pressure accumulator for the e ngine vacuum i , been system and the seals for the injectors have integrated into the cylinder head cover. o
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S465_034
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Engine Components Balancer shaft module A balancer shaft is located in the engine crankshaft drive. It has th e task of reducing vibrations and thus making the engine run quieter. The upwards and downwards movements of the pistons and connecting rods as well as the rotary movement of the crankshaft produce forces that cause vibrations. These vibrations are transferred to the vehicle body via the engine mounts. The balancer shaft acts against the forces of the pistons, connecting rods and crankshaft to reduce the vibrations. The balancer shaft has been integrated into a balancer shaft module together with the ladder frame and the oil pump. It is driven by the crankshaft via a chain. The balancer shaft rotates at engine speed in the opposite direction to the engine.
Crankshaft
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Balancing weights
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Oil pump drive sprocket
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Toothed belt drive The exhaust camshaft, the high-pressure pump for the common rail system and t he coolant pump are driven by the toothed belt. Toothed belt
Camshaft sprocket
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Poly V-belt drive for vehicles without air m m conditioning compressor
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Crankshaft S465_092
Poly V-belt drive for vehicles with airconditioning compressor
Alternator Belt tensioner
The ancillary components are driven by a conventional poly V-belt in this case. The poly V-belt is tensioned by a spring-loaded belt tensioner.
Poly V-belt Air-conditioning compressor Crankshaft
Follow the instructions in the workshop manual when fitting the poly V-belt.
S465_036
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Engine Components Oil system A duocentric oil pump generates the oil pressure required to lubricate the engine. It h as been integrated into the balancer shaft module and is driven by the crankshaft via a chain. The pressure relief valve is a safety valve. It prevents engine components being damaged by excessive oil pressure, for example, at low outside temperatures and at high engine speeds. The oil pressure regulating valve regulates the engine oil pressure. It opens as soon as the oil pressure has reached the maximum permitted value. The filter bypass valve opens if the oil filter becomes clogged up to ensure lubrication of the engine.
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e S465_037 s
s
Legend
o p
s
o
r
u p
f
i n f o r m
l
a i
1 2 3 4 5 6 7 8 9 10
-
c r
e Oil sump m m o Oil level c and oil temperature sender G266 r o e Oil pump t a v i r Oil pressure regulating valve p r o f g Pressure relief valve n i y p Hydraulic chain o tensioner C . t h g y Oil non-return valve i r p o c y b d e t c Oil cooler e t o r P Oil filter
a 10 - Filter bypass valve o n 11 - Crankshaft n h i 12 - Jets for piston d s cooling o c 13 - Camshafts m u e 14 - Vacuum . t n pump C o 15 - Oil i pressure switch F1 y p g r h t b 16 - o V yTurbocharger l k s w a g 17 - Oil return e n A . G 18 - Balancer shaft t i
i
t
G. Volksw age n AG g e n A d oe
w a l k s o
y V d b
s n
e i s r o h t u a
o t g u a r a n t
e e
o r a
s s e l
c c
e p
n
u d
Oil pump
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w The duocentric oil pump by the crankshaft i n has been integrated into the balancer shaft ladder frame and is driven t h e via a chain. The chain l eis tensioned by a hydraulic chain tensioner. s s
i ,
r
o h
p
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w
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s
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s
s s
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f
i n f o r
l
a i
m
c r e
Connection for oil a t i o pick-up pipe n
m m
o c r o
i n t h i s d o c
e t a v i r p r
u m
o f
g n
e n t .
C
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
o p r y i g h t
Oil pressure regulating valve
b y
V l o k s w a g e n A
. G
S465_038 Oil pressure relief valve
Oil pump
Oil sump The oil sump has been expanded with additional volume to accommodate the quantity of oil required by the engine.
Additional volume
Oil level and oil temperature sender G266 (for vehicles with extended servicing intervals) S465_093
11
Engine Components Coolant circuit The coolant is circulated around the coolant circuit by a mechanical coolant pump. The pump is driven by the toothed belt. The system is controlled by an expansion-type thermostat.
n AG a g e
w l k s V o
y d b
e i s r
o
h t u a
. Volksw age n AG
d oe
s n
o t g u a r a n t
e e
o r a
s s e l n
c c
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u d
t a
n y
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l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
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e s p e
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w
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n
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o
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t
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a p
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n i ,
e
c
s
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e
s
s s
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r
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f
i n f o r
l
a i
m
c r e
a
m m
t i o
n i n
o c r o
t h
u m
e n t .
o f
Legend g n i
y p
o
1 2 3 4 5
12
-
S465_040
i s d o c
e t a v i r p r
C . t h g
C
o p r y i g h t b 6 V y
r Radiator i for engine coolant circuit y p o c l o y k b s w d e a Thermostat t g c e e t o n A r P . G Coolant pump Oil cooler Cooler for exhaust gas recirculation
7 8 9 10
-
Coolant circulation pump 2 V178 Expansion tank Heat exchanger for heating system Coolant temperature sender G62 Radiator outlet coolant temperature sender G83
Low-temperature exhaust gas recirculation y V
d b
. Volksw age n AG
n AG a g e
w l k s o
d oe
s n
o t g u a r a n t e
e i s r
o
h t u a
e
The engine is equipped with a low-temperature exhaust gas recirculation system to reduce the NO x emissions. s s e l
o r a
c c
e p
n
u d
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
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s s
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l
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a
m m
t
i o n i n
o c r o
t h i s d o c
e t a v i r p r
u m
o f
g n
e n t .
C
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
o p r y i g h t b V y
l o k s
w a g e n A . G
S465_041
Function When the thermostat is closed, the exhaust gas recirculation cooler is supplied with cold coolant straight from the engine radiator. A larger quantity of exhaust gas can then be recirculated due to the resulting greater drop in temperature. This allows the combustion temperatures and consequently the nitrogen oxide emissions to b e further reduced during the engine warm-up phase. The electrical auxiliary water pump (coolant circulation pump 2 V178) is activated by the engine control unit and runs constantly once the engine has been started.
13
Engine Components n AG a g e
w l k s V o
. Volksw age n AG
d oe
s n
y d b
Intake manifold with swirl flaps e i s r
o
h t u a
o t g u a r a n t e
e
s s e l n
o r a
Intake manifold
Continuously variable swirl flaps are fitted in u the d e t intake manifold. m r e position The swirl of the intake air is a djusted via p the t o n speed and of the swirl flaps in relation to the engine e load. l o h The swirl flaps are fixed on the swirl flap w shaft and are n moved by the intake manifold flap motor via a push o rod. The positioning motor is actuated by the engine i , control unit for this purpose. The intake manifold flap potentiometer o G336 has p u been integrated into the intake manifold flap motor p a V157. It informs the engine control unit c about the r e m current position of the swirl flaps.
c c Intake e manifold p t a flap motor V157 n
y
t i
l
i a b i l i
t y
w i t
s i
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r
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a p
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s
s s
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f
i n f o r
l
i
m
a
t i o
m
n
o c r o
n S465_043 t h i
i s d o c
e t a v i r p r
u m
o f
g n
e n t .
C
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
o p r y i g h t b V y
l o k s w
a g e n A . G
Design
Charge pressure sender G31
Intake manifold flap motor V157
Swirl port
Swirl flap
Charge port
Swirl flap shaft
Push rod
14
S465_044
. Volksw age n AG
G e n A a g
w l k s o
y V d b
d oe
s n
e i s r
o
h t u a
o t g u a r a n t e
e
o r a
s s e l
c c
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n
u d
t a
n y
e t t
l
i
i a b i l i
m r e
Function of the swirl flaps
p
t y
t o
w i t
n
s
h
While the engine is running, the swirl flaps are e l o h and engine constantly adjusted according to the load w n speed. As a result, the optimum air movement is o present in the combustion chamber for all operating ranges. i , i ,
r
e s p e c
t t
i
o
r
t
h e c
t
r
a p
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c
s
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s s
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In the lower partial load range, the swirl p flaps close u p a between halfway and fully. c r This causes a high level of swirling, which e leads to m m o good mixture formation. c
o
r
f
i n f o r
l
i
m
a
t i o
n i n t h i s
r o
e t a Swirl v i r p r
flap
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g n
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C . t h g
i r y p
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y b
d e t c e t o r P
r y i g
e n t .
C
o p
p port Charge o
Swirl port
d
o c
h t b y
V l o k s w
a g
e n A . G
S465_045
The swirl flaps are fully open when the engine is started, at idle and at full throttle. Good filling of the combustion chamber is achieved thanks to t he increased air throughput.
Swirl flap
Charge port Swirl port
S465_046
15
Engine Components Fuel system Schematic overview 1 - Fuel system pressurisation pump G6 lksw
age n A G. Vo G d o The fuel system pressurisation g e n Apump constantly e s w a s k n o l o t g y V u a delivers fuel to e the b supply line at a pressure of d r a n t s i r e o e approx. 6 bar. h t o u
a
r a
s s e l n
c c
e p
u d
t a
2 - Pressure regulator for fuel supply line e
n y
t t
l
i
i a b i l i
m r e
p t The pressure control valve regulates the pressure in o n the fuel supply line to approx. 5 bar and sends the e l o h extra fuel back to the fuel tank.
t y
w i t
s i
h
,
r
e s p e
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c
t t
n
i
o
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o t
r
a p
t
3 - Fuel filter
h e c
o r r
n
e
i , s
c
The fuel filter keeps impurities in the diesel fuel away o p from the components of the injection system. The high u p precision components, for example, the h igh-pressure a c r pump and the injectors, can be damaged or their e m m function impaired by even the most minute particles o c r o of dirt. e
t
n
e
e
s
s s
o
r
f
i n f o r m
l
i
a t i o n i n
t h i s o c
t a v i r p r
u m
o f temperature sender G81 4 - Fuel g
n i y
p
o
h The fuel sender measures the current i t r b y p V y o c o l k b s fuel temperature. y w d e a t g c e t o r P
e n t .
C
o p
r y i g
C . t h g temperature
d
e n A . G
5 - High-pressure pump The high-pressure pump generates the high fuel pressure required for injection. Colour code/legend High pressure 230 – 1,800 bar Supply pressure 5 bar Return pressure 0.3 bar Return pressure from the injectors (negative pressure) –0.1 bar to –0.5 bar
16
6 - Fuel metering valve N 290 . Volksw age n AG
n AG a g e
w l k s V o
b y
e d i s r o h t u a
s
s e l n
d
oe s The fuel metering valve regulates the quantity n o t g u a r a of fuel needed to generate the high n t pressure as e e o r required. a c c
e p
u d
t a
n
7 - Fuel pressure regulating valve N276 y i a
e t t
l
i
m r e
b i l i
p
t y
t o
The fuel pressure regulating valve opens belowi t h a certain fuel temperature to pre-heat the fuel e p s e filter. w
n
s i ,
r
e l
o h
w
c
t t
n
i
o
r
o
t
h
t
r
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8 - High-pressure accumulator (rail)
a p
o r r
n i ,
e
c
s
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The high-pressure accumulator stores the fuel required for injection into all cylinders under high pressure.
s
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a i
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t
n
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s s
o
f
i n f o r
m
a
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9 - Fuel pressure sender G247
o c r o
e t a v i r p r
t i o
n i n t h i s
d
o
c u The fuel pressure sender measures the current m e n t fuel pressure in the high-pressure area. . C
o f
g n
i y
p
o
C . t h g
i r y p
o c
10 - Injectors N30, N31,
y b
d e t c e t o r P
o p r y i g h t b N32 V y
l o k s w
a g e n A . G
The injectors inject the fuel into the combustion chambers.
11 - Venturi nozzle S465_047
The venturi nozzle in the high-pressure pump generates the negative pressure in the fuel return of the injectors.
17
Engine Components Fuel system pressurisation pump G6 The fuel system pressurisation pump is an electrically driven crescent pump. It has been integrated into the fuel delivery unit and generates a pressure of approx. 6 bar in the f uel system supply line. This ensures that the highpressure pump is supplied with sufficient fuel in a ll operating states. The fuel pump is activated by the engine control unit via a relay when the engine is started.
Fuel return line
Return line fuel lksw a ge n AG . Vofrom n AG d oe a g e s n pressure regulator o t
w l k s V o
b y
e d i s r
Fuel supply line
o
h t u a
g u
s s e l n
a r a n t
e e
o r a
c c
e p
u d
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
n
w i t
Electrical connection
s i ,
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h r
e s p e
o h
Fuel delivery wunit
c
t t
n
i
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o
t
h e c
t
r
a p
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c
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s
s s
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f
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l
a i
m
c r e
a
m m
t i o
n i n
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i s
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d
o c
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e n t .
o f
g n
Fuel pump o C p
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p
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C . t h g
i r y p
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y b
d e t c e t o r P
l o k s
w a g e n A G
.
r y i g h t b V y
S465_051 Crescent pump
Effects upon failure The engine will not run if the fuel system pressurisation pump fails.
S465_052
18
Fuel pressure regulator The fuel pressure regulator is located near the vehicle floor on the right-hand side of the fu el tank. The fuel pressure regulator reduces the fuel pressure generated by the fuel system pump in the fuel age n A . Volksw pressurisation G G d o g e n A e s w a s k n l o t supply line to approx. 5 bar. This results in a con stant pressure y level V o in the fuel supply line. g u b
e d i s r o h t u a
a r a n t
e e
o r a
s s e l
c c
e p
n
u d
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
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Fuel tank
h
Fuel delivery unit
,
o h
r
e s p e
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c
t t
n
i
o
r
o
t
h e c
t
r
a p
o r r
n
e
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c
s
Return line from pressure regulator to fuel delivery unit
t
n
e
e
s
s s
o p
o
r
u p
f
i n f o r
l
a i
Supply line to fuel filter and high-pressure pump
c r e
m m
m
a
t i o
n i n t h i s
o c r o
e t a v i r p r
u m
o f
g n
i y
o
C . t h g
i r y p
o c
y b
Return line from high-pressure pump
d e t c e t o r P
How it works
r y i g
e n t .
C
o p
p
Fuel pressure regulator
d
o c
h t b y
V l o k s w
a g
e n A . G
S465_053
The fuel delivered by the fuel system pressurisation pump reaches the fuel pressure regulator via a branch channel. A spring-loaded diaphragm valve in the chamber of the fuel pressure regulator sets the fuel pressure at approx. 5 bar. If the pressure rises above 5 bar, the diaphragm valve opens and the fuel flows back into the fuel delivery module. Diaphragm valve Fuel pressure regulator
Direction of flow
Fuel return to fuel delivery unit S465_081
The fuel pressure regulator is also called additional fuel fi lter in the repair literature. The filter in the chamber does not have any function, however. This component only has the task of regulating the fuel pressure in the low-pressure system.
19
Engine Components . Volksw age n AG
n AG a g e
w l k s V o
d o e
s n
y d b
o t g u a r a n t
e i s r
Common rail fuel injection system o
h t u a
e e
o r a
s s e l n
c c
e p
u d
t
a The common rail fuel injection system for the 1.2l TDI engine was developed by Volkswagen and DE LPHI. n y e t t
l
i
i a b i l i
m r e
y p t pressure generation and the fuel injection are separate in the common The w rail injection system. The high-pressure o i n t h pump generates the high fuel pressure required for injection. e t
s
i ,
r
e l
s p
o h
e c
w
This fuel pressure is stored in the high-pressure accumulator (rail) and is supplied to the injectors via short injector o h o pipes. A venturi nozzle integrated in the high-pressure pump creates a negative pressure in the fuel return of the o e i , injectors that allows a high injector operating speed. t t
n
i
r
t
e c
t
r
a p n
r r
s
c
t
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e
s
o p r
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s
s The common rail fuel injection system is regulated by the Delphi DCM 3.7 engine management system. o
u p
f
i n f o r
l
a i
m
c r e
a
m m
t i o
n i n
o c r o
t h
i s d o c
e t a v i r p
u m
r o f
g n
e n t .
C
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
l o k s
w a g e n A G
.
o y p r i g h t b V y
S465_086
The common rail fuel injection system provides many options for adapting the injection pressure and the injection process to the engine operating mode. The characteristics of the common rail injection system are:
20
A high injection pressure up to a maximum of 1,800 b ar enables good mixture formation. The injection pressure can be selected almost infinitely and can be adapted to the current engine operating status. The injection process can be made flexible with s everal pilot injections for quiet combustion and several secondary injections for regeneration of the diesel particulate fi lter.
High-pressure pump The high-pressure pump is a single-plunger pump. It is driven at engine speed by the crankshaft via the toothed belt. The high-pressure pump has the task of generating the high fuel pressure of up to 1,800 bar, which is required for fuel injection. The two cams on the drive shaft are offset by 180°. A roller, which runs on the cam of the drive shaft, ensures low-friction power transmission to the pump plunger. G. Volksw age n AG The high-pressure pump housing contains athe fuel g e n A d oe w s n s k l o t o V metering valve N290 for regulating th e fuel flow g u y b a r d a n e s i venturi nozzle for t r e in the high-pressure area and a o e h t o u r a c a generating negative pressure in the fuel return of s c s e e l p n t u a the injectors. n d e
t t i
S465_072
y
l
i a b i l i
m r e
p
t y
t o
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s
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Design of high-pressure pump w
c
t t
n
i
o
r
o
t
h e c
t
r
a p
o r r
Intake valve
n
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e
c
n Fuel e s metering valve N290 s t
e
s
o p
o
r
u p
f
n f o r
i
l
a i
High-pressure connection a to rail m
c r e
m m
o c r o
Drive shaft
t
i o n i n
Pump plunger
t h i s o c
e t a v i r p r
u m
o f
g n
i y
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
r y i g
e n t .
C
o p
p
d
Fuel inlet
Fuel return
h t b y
V l o k s w
a g
e n A . G
Roller Drive cam
S465_030
21
Engine Components Design of high-pressure pump – schematic The high-pressure pump is supplied with sufficient fuel by the fuel system pressurisation pump in all operating modes of the engine. The fuel reaches the high-pressure area of the rail system via the fuel metering valve. The pump plunger is moved upwards and downwards by the cams on the drive shaft.
Intake valve Outlet valve Connection to rail
y V
b
e d i s r o h t u a
n AG a g e
w l k s o
. Volksw age n AG
d o e
Fine filter
s n
o t g u a r a n t
Fuel metering valve N290
e e
o r
a c
s s e l
c
e p
n
u d
Pump plunger
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
s
h
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Plunger spring
Fuel return from the injectors
w i t
n
r
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e s p e
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w
c
t t
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i
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t
h e c
t
r
a p
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n i , s
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c
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s
s s
o p
o
r
Roller
u p
f
i n f o r
l
a i
m
c r e
a
m m
t
i o n i n
o c r o
Drive shaft with cams
t h i s o c
e t a v i r p r
u m
d
Venturi nozzle
e n t .
o f
g n
C o p
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
r y i g h t b V y
o
l k s w a g e n A G
.
S465_082
22
Fuel return to tank
o
r
Fuel supply line
Suction stroke The downwards movement of the pump plunger increases the volume of the compression chamber. This causes a difference in pressure between the fuel in the high-pressure pump and the fuel in the compression chamber. The intake valve opens and fuel flows into the compression chamber.
Intake valve a
w l k s
o y V
G. Volksw age n AG g e n A
d oe
s n
o t g u a r a n t e
d b
e i s r
o
h t u a
o r a
s
s e l n
Compression chamber
e
c c
e p
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t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
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Pump plunger
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e l
r
e s p e
o h
w
c
t t
n
i
o
r
o
t
h e c
t
r
a p
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n
e
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t
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s
s s
o p
o
r
u p
f
i n f o r m
l
a i
c r e
a
m m
t
i o n i n
o c r o
t h i s d o c
e t a v i r p r
u m
o f
g n
e n t .
C
i y
p
o
C . t h g
i r y p
o c
y b
d e t c e t o r P
o p r y i g h t b V y
l o k s
w a g e n A . G
S465_084
23
Engine Components Delivery stroke The pressure in the compression chamber increases and the intake valve closes when the pump plunger starts to move upwards. As soon as the fuel pressure in the compression chamber exceeds the pressure in the hi gh-pressure area, the outlet valve (non-return valve) opens and the fuel enters the high-pressure accumulator (rail).
. Volksw age n AG
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m
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Connection to highpressure accumulator (rail)
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n i n h i s d o c t
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Outlet valve
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l o k s
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Pump plunger
S465_085
24
Fuel metering valve N290 The fuel metering valve has been integrated into the high-pressure pump. It ensures that the fuel pressure is regulated as required in the high-pressure area. The fuel metering valve regulates the fuel quantity that is required to produce high pressure. The advantage of this is that the high-pressure pump only has to generate the pressure that is required for the current operating situation. This reduces the power consumption of the h igh-pressure pump and avoids unnecessary fuel heating.
Function When no current is supplied, the fuel metering valve is open. To reduce the quantity flowing to the compression chamber, the valve is actuated by the engine control unit with a pulse-width modulated (PWM) signal.
The fuel metering valve is pulsed closed by the PWM signal. The position of the control plunger and therefore the quantity of fuel flowing into the compression chamber of the high-pressure pump varies in relation to the pulse control factor.
To compression chamber Control plunger Inlet from inside of pump
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S465_073
i n
t h i s d o c
e t upon failure Effects a v i
u m
r p r
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The engine g output is reduced. The engine management system operates in emergency running mode. n i C
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l o k s
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25
Engine Components Venturi nozzle The venturi nozzle generates negative pressure in the fuel return of the injectors. It has been integrated into the housing of the high-pressure pump. The negative pressure in the injector fuel return aids fast opening and closing of the injectors during the injection process.
Fuel metering valve . Volksw age n AG
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w l k s V o
y d bFuel inlet
e i s r
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Fuel return from the injectors
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Fuel return
o h
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Venturi nozzle
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Sealing flange
s s
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m
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m m
S465_027
t i o
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a How i r it works v
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y is not required for injection is diverted by the fuel C The fuel i that p ometering valve into the fuel return in the direction o C y p . r t i g of the venturi h nozzle. h g i t r b y y p V o c l o y k The constricted cross-section of the funnel-shaped nozzle increases the flow rate of the fuel because the same b s w d e a t g c e e t o n A r G P . quantity flows through everywhere. The high flow rate at the narrowest point in the venturi nozzle creates a suction effect in the fuel return of the injectors. This suction effect creates the negative pressure in the injector fuel return, which aids fa st opening and closing of the injectors during the injection process.
If there are differences in the negative fuel pressure of the injectors, there may be a lack of power at high engine loads and faults could occur.
26
Injectors The injectors are secured in the cylinder head with clamping pieces. They have the task of injecting the right quantity of fuel into the combustion chambers at the right time. They are actuated by the engine control unit.
Design
High-pressure connection
High fuel pressure
Connection for fuel return
Fuel return
Electrical connection
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Switching valve spring
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Switching valve
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Nozzle needle spring
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Nozzle needle
t h i s d o c
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S465_080
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V l o k s
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S465_075
27
Engine Components Injection process Injector in resting position The injector is closed in its resting position. The solenoid valve is not actuated. Solenoid
The switching valve closes the path from the control chamber to the fuel return. High fuel pressure is present in the control chamber and at the nozzle needle.
Switching valve
The pressure conditions at the nozzle needle and in the control chamber are balanced. The nozzle needle is pushed into its seat by the force of the nozzle spring. Control chamber
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Nozzle spring
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Nozzle needle
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t
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S465_006
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V l o k s w a g e n A
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u m
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28
t h i s o c
d
Start of injection Phase 1 The start of injection is initiated by the engine control unit. It does so by actuating the solenoid valve.
Solenoid
A magnetic field is formed in the solenoid, which lifts the switching valve out of its seat. The opening movement of the switching valve is supported by the negative pressure in the fuel return. This opens the path from the control chamber to the fuel return. The fuel in the control chamber flows into the fuel return via the outflow restrictor. This reduces the fuel pressure in the control chamber that pushes the nozzle needle into its s eat. The inflow restrictor to the control chamber is smaller than the outflow restrictor to prevent a quick pressure equilibrium.
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Inflow restrictor
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Outflow restrictor
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S465_013
a t i o n i n
m m
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V l o k s w
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29
Engine Components Start of injection Phase 2 As soon as the fuel pressure at the nozzle needle exceeds the pressure in the control chamber and the force of the nozzle spring, the nozzle needle is lifted out of its seat and injection begins. The negative pressure in the fuel return supports the drop in fuel pressure in the control chamber and thus increases the opening speed of the injector. The opening travel of the nozzle needle is limited by the stop in the control chamber.
Control chamber
Nozzle spring
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Nozzle needle
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e n t .
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V l o k s w a g e n A
. G
S465_016
End of injection Phase 1
Fuel return
The end of injection is initiated by the engine control unit. It does this by ending the actuation of the solenoid valve. The switching valve is pushed into its seat by the force of the switching valve spring and thus closes the path from the control chamber to the fuel return.
Switching valve spring Switching valve
The closing speed is increased by the negative pressure in the fuel return.
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S465_019
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31
Engine Components End of injection Phase 2 In the control chamber, the fuel pressure rises again until it is as high as the pressure at the nozzle needle. y V
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The force of the nozzle spring ends the equilibrium s e i r o h t of forces above and below the nozzle needle and u a s s e pushes the nozzle needle into its seat. l n
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m injector r The injection process is completed and e the p t o is in its resting position again. n
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Control chamber e
The injection quantity is determined by the solenoid valve actuation duration and the rail i , pressure. The negative pressure in the fuel return allows fast o p movements of the solenoid valve. This allows several u p a injections to be made per working cycle and the c r e injection quantities to be adjusted precisely. m t
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Nozzle needle
S465_078
32
Correction value for the injection valves There is a data carrier on the top of the injectors. In addition to manufacturer-specific details, the VW part number and a 20-digit correction value are stamped onto this data carrier. The correction value compensates injection performance differences between the injectors that result from manufacturing tolerances.
Correction value (20-digit) VW part number
The correction value is determined on a test rig during . Volksw age n AG n AG a g e injector production. It indicates deviations from thed oe w s n s l k o t o V g u y b describes the injection a r d specifications and s thus a n e i t r e o e h o performance of u tthe respective injector. r a
S465_098
a
s s e l n
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t o The nengine control unit can use the correction value to control and correct the actuation of single injectors e l o h across the whole mapped range. This allows precise w n control of the injection quantities, which contributes to o the reduction of fuel consumption and exhaust gas emissions as well as to quiet engine running. i ,
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Data carrier with correction value
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When injectors are replaced, the correction value must be entered in the guided fault finding system under the “Read/adapt injector correction values” menu option.
o y p r i g h t b V y
S465_101
33
Engine Components High-pressure accumulator (rail) The rail is a high-pressure accumulator for the fuel that is delivered by the high-pressure pump. It supplies the injectors with the quantity of fuel required for injection.
High-pressure accumulator (rail)
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Fuel pressure sender G247
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Fuel pressure sender G247
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The fuel pressure sender measures the current fuel pressure in the high-pressure accumulator (rail). a c r m Evaluation electronics in the fuel pressure sender convert the hydraulic pressure into a voltage signal that is e a m o evaluated by the m engine control unit. n o i n f o r
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Signal use
e t a v i r p r
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The signal from the fuel y pressure sender is used by the engine control unit to p o C calculate the actuation duration p o C y . r t i g h of the injectors and the high-pressure regulation by the fuel metering valve. h g i t r b i
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o c
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Effects of signal failure
d e t c e t o r P
The engine will not run if the fuel pressure sender fails.
34
V o
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Fuel pressure regulating valve N276 The fuel pressure regulating valve is located on the high-pressure accumulator (rail). The engine control unit actuates the regulating valve with a pulse-width modulated signal and thus sets the fuel pressure in the high-pressure area. Fuel pressure regulating valve N276
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S465_094
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Solenoid
High-pressure accumulator (rail)
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Electrical connection
m
c r e
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Valve needle
t
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Valve armature
u m
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S465_095 Return to the fuel tank
Valve springs
35
n AG a g e
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Engine Components e i s r
o
h t u a
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s s e l
c c
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i
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How it works n
s i
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,
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Regulating valve i n resting position (engine “off”) w
c
t t
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If the regulating valve is not actuated, the pressure i , regulating valve is opened by the valve springs. The high-pressure area is connected to the fuel return. o a p
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This ensures a volume balance between the high c r e pressure m and low-pressure fuel areas. Vapour m o bubbles, c which can f orm in the high-pressure r o e t (rail) during the cooling process after accumulator a v i p the engine is r switched off, are avoided and the r o f g n starting behaviour of the engine is thus improved. i y
m
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d e t c e t o r P
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l o k s w a
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g
S465_096 Valve springs
Regulating valve actuated (engine "on") To set the operating pressure of 230 to 1,800 bar in the high-pressure accumulator, the regulating valve is actuated by the engine control unit. This leads to a magnetic field in the solenoid. The valve armature is attracted and presses the valve needle into its seat. The fuel pressure in the high-pressure accumulator is therefore opposed by a magnetic force. When the engine has reached operating temperature, the high fuel pressure is regulated exclusively by the fuel metering valve. The fuel pressure regulating valve is fully closed.
Solenoid
S465_097
Effects upon failure The engine will not run if the f uel pressure regulating valve fails because it is not possible to build up sufficient fuel pressure for fuel injection.
36
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 crystallised paraffin. To allow the fuel to be warmed quickly when the engine is cold, the fuel metering valve N290 is regulated to supply more fuel than is required for injection to the pressure chamber of the high-pressure pump. The fuel warmed during pressurisation is sent from the high-pressure accumulator (rail) via the fuel pressure regulating valve N276 into the fuel filter return line. As soon as the fuel reaches a certain temperature, the fuel pressure regulating valve remains fully closed. The high fuel pressure is then regulated exclusively by the fuel metering valve N290.
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Legend 1 2 3 -
S465_099
m
c r e
a
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t
i o n i n
o c r o
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Fuel filter o f g n Fuel temperature sender G81 i y p o C Fuel metering valve N290 . t h
t h i s o c
d
u High-pressure pump m e n t High-pressure C accumulator (rail) . o p Fuel pressure r y regulating valve N276 i g
4 5 6 -
g i r y p
o c
y b
d e t c e t o r P
h t b y
V l o k s w
a g
e n A . G
37
Engine Management System overview
. Volksw age n AG
G e n A a g
w l k s V o
Sensors
d oe
s n
y d b
o t g u a r a n t
e i s r
o
h t u a
e e
o r a
s s sender G28 Engine speed e l
c c
Glow period warning lamp K29
e p
n
u d
t a
n y
e
t t i
Hall sender G40 m
l
i a b i l i
r e
p
t y
t
o Accelerator position sender G79 n Accelerator position sender 2 G185 e l
w i t
s i
r
e s p e
o h
w
c
t t
n
Air mass meter G70 o
i
o
r
t
h e c
t
r
a p
o r r
n Coolant temperature sender G62 i ,
e
c
s
Exhaust emissions warning lamp K83
t n
e
e
s
s s
o p
Radiator outlet coolant temperature sender G83 u
o
r
f
p
i n f o r
l
a i
m
c
r Charge pressure sender G31 e m m air temperature sender G42 Intake o
a
t i o
n i n
c r o
t h
i s d o c
e t a v i r p r
Fuel temperature sender G81
u m
o f
g n
. t h g
i r y p
Knock sensor 1 G61
o c
y b
d e t c e t o r P
.
Lambda probe G39 Exhaust gas pressure sensor 1 G450 Exhaust gas temperature sender 1 G235 Exhaust gas temperature sender 3 G495 Exhaust gas temperature sender 4 G648 Brake light switch F Clutch position sender G476 Position sender for charge pressure positioner G581
Throttle valve potentiometer G69 Oil level and oil temperature sender G266
o y p r i g h t b V y
l o k s
w a g e n A G
Exhaust gas recirculation potentiometer G212
Intake manifold flap potentiometer G336
e n t .
C
i y
Fuel pressure p sender G247 o C
38
Diesel particulate filter warning lamp K231
h
,
Control unit in dash panel insert J285
Actuators Fuel supply relay J643 Fuel system pressurisation pump G6 Injector, cylinder 1 N30 d o e Injector, cylinder 2 N31 s n o t g u a r Injector, cylinder 3 N32 a n
. Volksw age n AG
G g e n A w a
l k s o
y V d b
e i s r
t e
o
h t u a
e
o r a
s s e l n
c c
e p N290 Fuel metering valve t a
u d
n y
e
t t i
CAN data bus m
l
i a b i l i
r e
p
t y
t o
Fuel pressure regulating valve N276 i t h w
n
s i ,
r
e l
e s p e
o h
w
c
t t
n
i
o
r
h Charge pressure control solenoid valve N75
o
t
e c
t
r
a p
o r r
n i ,
e
c
s
t n
e
e
s
s
o p
s Intake manifold flap motor V157 o
r
u p
f
i n f o r
l
a i
m
c r e
a
m m
t i o
n i n
o c r o
t h
i s d o c
e t a v i r p r
u m
e n t .
o f
g Engine control unit J623 n i y
C Throttle valve module J338 o
p
o
p r y i g h t b V y
C . t h g
i r y p
o c
y b
d e t c e t o r P
l o k s w
a g e n A . G Exhaust
Diagnosis connector
gas recirculation valve N18
Exhaust gas recirculation cooler changeover valve N345
Coolant circulation pump 2 V178
Lambda probe heater Z19
Automatic glow period control unit J179 Glow plug 1 Q10 Glow plug 2 Q11 Glow plug 3 Q12 S465_076
39
Engine Management Engine control unit The engine management system for the 1.2l TDI G. Volksw age n AG engine with common rail injection system isAnamed: n d a g e w l k s o
o e s n
y V d b
o t g u a r a n t
e i s r o h t u a
Delphi DCM 3.7
e e
o r
a c
s s e l
c
e p
n
Delphi = manufacturer of engine management u d e t system m r e p DCM = Diesel Control Module t o n 3.7 = development stage
t a
n y
t i
l
i a b i l i
t y
w i t
s
h
i ,
r
e l
e s p e
o h
The engine n wmanagement system checks all processes o that are required for regulation of the injection system and control of the engine. In addition, the engine i , control unit communicates with control units for other o vehicle systems via the CAN data bus to exchange p u p information.
c
t t
i
S465_079
o
r
t
h e c
t
r
a p
o r r
n
e
c
s
t
n
e
e
s
s s
o
r
f
i n f o r
l
a i
m
c r e
a
m m
t
i o n i n
o c r o
t h i s o c
e t a v i r p r
u m
o f
g n
e n t .
C
i y
p
Turbocharger
d
o
C . t h g
i r y p
o c
y b
d e t c
o p r y i g h t
b y
V l o k s w a g e n A
e t o r P . G The charge pressure of the 1.2l TDI engine is generated by a turbocharger with adjustable guide vanes. The flow of exhaust gas to the turbine wheel of the turbocharger can be varied with the adjustable guide vanes. The advantage of this is that optimum charge pressure and therefore good combustion can be achieved throughout the entire engine speed range.
The design and function of the turbocharger are explained in self-study programme no. 190 “Adjustable Turbocharger”.
40
S465_106 Turbocharger
Charge pressure regulation
1
2 9
Legend
1 - Vacuum system 2 - Engine control unit J623 . Volksw age n AG 3 - Intake air n AG d oe a g e s n s w k 8 l V o g u 4 - o t Charge pressure control solenoid valve N75 y 3 b a r d a n e s i t r e 5 - Turbocharger compressor 4 o e h t o u r a a c with position sender for charge s 6 - Vacuum unit c s 10 e e5 l p n t u a pressure positioner G581 n d y e t i a 7 - Exhaust turbine with guide vane adjustment b m r i e p 8 - Charge air cooler y w t o i n t h sender G42 9 - Intake air temperature e 6 e s l p 10 Charge pressure sender G31 o e h t i
l
l i t
s
i ,
r
w
c
n
t t
7
i
r
o
o
t
h e c
t
r
a p
o r r
n
e
i ,
c
s
t
n
e
e
s
o p
s s
S465_077
r
u p
o
f
i n f o r
l
a i
c r e
m m
o c r o
e t
m
a
t i o
n i n t h i s
d An increase in output ois also obtained by using a c u charge air cooler. n e m The combustion air drawn in t n . i y C through the air filter is heated greatly on the way p o o p C y . r i g h The turbocharger increases t h the pressure in the intake to the engine, particularly in the turbocharger. The g i t r b y y p V o o c l y k b system of the engine so that a greater quantity of air quantity of air and thus the quantity of oxygen s w d e a t g c e e t o n A r P G . enters the cylinder on the intake stroke. This provides available for combustion are reduced. The air is more oxygen for combustion of a correspondingly cooled again in the charge air cooler and the air larger quantity of fuel. The result is increased output density is thus further increased. with the same displacement and the same engine speed. a The charge pressure v regulation controls the quantity i r p r o of air that is compressed by the turbocharger. f g
You will find further information on charge pressure regulation in self-study programme no. 403 “The 2.0l TDI Engine with Common Rail Injection System”.
41
Engine Management Throttle valve module J338 y V
d b
e i s r
o
h t u a
. Volksw age n AG
n AG a g e
w l k s o
d oe
s n
o t g u a r a n t e
e
s The throttle valve module is mounted on the engine s e l n u intake manifold. d
o r a
c c
e p
t a
n y
e t t
l
i
i a b i l i
m r e
p There is an electric motor in the throttle valve module t o n that operates the throttle valve via gears. Adjustment e l of the throttle valve ois infinite and can therefore be h w adapted to the relevant engine load and speed. n
t y
w i t
s i
h
,
r
e s p e c
t t
i
o
r
o
t
h e c
t
r
a p
o
The throttle valve module has the following tasks:
r r
n
e
i , s
c
t
n
e
e
s
o In certain operating p situations, the throttle valve u p between the intake manifold creates a difference a c r pressure and the exhaust gas pressure. Effective e m exhaust gas recirculation m is achieved due to the o c pressure difference. r o
s s
o
r
f
i
e t a v i r p r
S465_116
i n f o r m
l
a Throttle valve module J338 with t i o n throttle valve potentiometer i G69
n t h i s
d
The throttle valve is used to o regulate the intake air f g n i y quantity when the diesel par ticulate filter is in p o C . t h regeneration mode. g i r y p
o c
y b
d e t c e t o r P
The valve is closed when the engine is switched off. Less air is therefore drawn in and compressed, as a result of which the engine stops smoothly.
o
c u m
Effect upon failure . t n e C
o p r y i g h t b of V y failure, correct
In the event regulation of the rate o l k s w a of exhaust gas recirculation is impossible. There is g e n A . G no active regeneration of the diesel particulate filter.
You will find more detailed information on the throttle valve module in self-study programme no. 368 “The 2.0l 125kW TDI engine with 4-valve technology”.
Throttle valve potentiometer G69 The throttle valve potentiometer has been integrated into the throttle valve drive. The sensor element detects the current position of the throttle valve.
42
Signal use
Effects upon failure
The engine control unit uses t he signal to recognise the current position of the throttle valve. This information is required for regulation of the exhaust gas recirculation and regeneration of the particulate filter.
In the event of failure, exhaust gas recirculation is switched off and there is no active regeneration of the diesel particulate filter.
Sensors
G. Volksw age n AG g e n A d oe
w a l k s o
y V d b
Knock sensor G61
s n
e i s r o h t u a
o t g u a r a n t
e e
o r a
s s e l n
c c
e p
u d
t a
n y
The knock sensor is a sensor that picks up the m r e and sends them to the engine vibrations of the engine p t o control unit in the form of a signal. In the d iesel n engine, the knock l esensor recognises the combustion o h process at the respective cylinder allowing the engine w n control unit to then adjust the actuation of the o corresponding injector. e t t
l
i
i a b i l i
t y
w i t
s
h
i ,
r
e s p e c
t t
i
o
r
t
h e c
t
r
a p
Knock sensor G61
o r r
n i ,
e
c
s
t
n
e
The knock sensor is located in the cylinder block next o p u position has been selected so that to cylinder 2. The p the best possible a signal can be received from all c r e cylinders. m
e
s
s s
o
r
f
i n f o r
l
i
m
a
t
i o n
m
Signal use
o c r o
i n
t h i s o c
e t a v i r p r
u m
o f
g The engine control unit uses the knock sensor signal n i y p o C to monitor the combustion process . and thus the actual t h g i r y p start of injection in the respective cylinder. The engine o c y b d e e t o control unit can therefore constantly adjust t c the r P actuation of the injector. As a result, any change in the performance of the injectors, which may occur over a long period of operation, can be compensated. The signal from the knock sensor allows precise metering of even the smallest injection quantities. As a result, fuel consumption and exhaust gas emissions are reduced.
d
e n t .
C
o p r y i g h t
b y
V l o k s w a g e n A
. G
S465_089
Please observe the information on fitting the knock sensor to the cylinder block in the workshop manual. Using an incorrect torque can lead to damage or a distorted signal.
43
Engine Management Design of knock sensor Ceramic piezoelectric element
The design of the knock sensor for the diesel engine corresponds with one for petrol engines. The structure-borne sound vibrations and the structure-borne sound of the e ngine are transmitted to the ceramic piezoelectric element in the sensor. These vibrations generate a voltage in the ceramic piezoelectric element that is sent to the engine control unit in the form of a signal. . Volksw age n AG
n AG a g e
w l k s V o
y d b
s n
e i s r
o
h t u a
d o e
Signal wire
o t g u a r a n t
e e
Electrical connection
s s e l
o r
a c S465_115 c e p
n
u d
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
h
,
r
e l
Injection recognition function
e s p e
o h
w
c
t t
n
i
o
r
o
t
h e c
t
r
In order to distinguish the structure-borne sound vibrations of the combustion process from the structure-borne o e i , in the crankshaft drive, the noises are detected by the engine control sound vibrations of the background noise n e unit in two time windows. Both measuring o results are then correlated and compared. s p o u In the first time window, the time of measurement is set so that no combustion can occur – for example, at bottom p n a o dead centre of the crankshaft. c r r m e a The intensity of combustion after a pilot injection is determined in the second time window. The time of the m o m n o c measurement is selected so that only the combustion noises caused by the pil ot injection are detected. The second n r o h i e s time window is therefore immediately before t the d a main injection. a p n
r r
s
c
t
e
s
s
r
f
i
l
f
i
t i
i
t
o
v i
c u m
r p r
e n t
o f
g n
. C o p
i y
p
o
C . Injection process with a pilot injection t h
g i r y p
o c
y b
d e t c e t o r P
Cylinder pressure
Pilot injection
Main injection
Actuation pulse Knock sensor signal Crank angle
BDC
TDC S465_103
44
V
l o k s w
a g e n A . G
r y i g h
t b y
n AG a g e
w l k s o
y V d b
Function of injection adjustment
. Volksw age n AG
d o e
s n
e i s r
o
h t u a
o t g u a r a n t
e e
o r
a c
s s e l
c
e p unit. A specification for the minimum actuation time of u nthe solenoid valve for injection is stored in the engine control t a n d y This actuation pulse must at least be present to t eallow injection. i a t i
l
m r e
b i l i
p t
t y
o
If the actuation pulse is too low, there is no ninjection since the actuation time is too short for the solenoid valve to lifti t h e the nozzle needle inside the injector. l e s p w
s
i ,
r
o h
e c
w
t t
n
If the actuation pulse is too large, too much fuel is injected since the nozzle needle in the injector stays open longer o than is specified. i
o
r
t
h e c
t
r
a p
o r r
n
e
i , s
c
t
n
e
When the injection is adjusted, the deviation from the minimum actuation time for a n injection is calculated using o p the stored specification. If the minimum u actuation time deviates from the specification, the engine control unit p a corrects the actuation time of the solenoid valve. c
e
s
s s
o
r
f
n f o r
i
l
i
r e
Learning process
m
a
m m
t i o
n i n t h i s
o c r o
e t a v i r p r
d
o c
u To find out the minimum actuation pulse for an injector, the engine control unit actuates the solenoid valve for a s et m o f e n g time. Then, depending on the combustion noise, the actuation time of the solenoid valve is shortened or lengthened t n . i y C p o o p until there is no longer a pilot injection. This actuation C value is stored as a correction value in the engine . r y control t i g h h g i t r b y unit. p V y o c o l k s w
y b
a g e n A . G
d e t c e t o r P
Long actuation pulse for pilot injection a
BDC
b
Short actuation pulse for pilot injection
c
TDC
a
b
c
Actuation pulse
Actuation pulse
Knock sensor signal
Knock sensor signal
S465_102
BDC
TDC
S465_120
a) Pilot injection for injection adjustment learning function b) Pilot injection for noise reduction c) Main injection
To reduce the combustion noises during the learning process for injection adjustment, there is another pilot injection immediately before the main injection. The minimum actuation time is calculated separately for each cy linder when the engine has reached operating temperature and in certain operating conditions.
Effects of signal failure A fault is recorded in the engine control unit when the knock sensor signal fa ils. The injectors are actuated with the actuation pulse values stored in the engine control unit.
45
Engine Management Exhaust gas recirculation system Exhaust gas recirculation is a system for reducing nitrogen oxide emissions. Thanks to exhaust ga s recirculation, sw age n . Volkcombustion AG d process. The reduction in the oxygen concentration of part of the exhaust gases are returned toGthe g e n A oe w a s n s k l o t o V g u combustion. This lowers the combustion peak the fuel/air mixture, which dresults from this process, causes slower b y a r a n e s i t r e temperature and reduces the nitrogen oxide emissions. o e h t o u a
r a
s s e l n
c c
e p
u d
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s i
h
,
r
e l
e s p e
o h
w
c
t t
n
i
o
r
o
t
h e c
t
r
a p
o r r
n
e
i , s
c
t
n
e
e
s
s s
o p
o
r
u p
f
i n f o r m
l
a i
c r e
a t i o n i n
m m
o c r o
t h i s o c
e t a v i r p r
u m
e n t .
o f
Legend
g n
C o p
i y
p
o
C . t h g
G39 G62 G69 J338 J623
i r y p
c y b Lambda probe d e t c e t o r P Coolant temperature sender Throttle valve potentiometer Throttle valve module Engine control unit o
A broadband lambda probe is located upstream of the particulate filter in the exhaust system. The lambda probe enables measurement of the oxygen content in the exhaust gas over a wide measuring range. The signal from the lambda probe is used as a correction value for regulating the exhaust gas recirculation quantity in the exhaust gas recirculation system.
S465_105
r y i g h
t b y
V l o k s
w a g e n A . G
The exhaust gas recirculation quantity is controlled on the basis of a map in the engine control unit. The engine speed, injection quantity, intake air mass, the intake air temperature and the air pressure are taken into account.
46
d
N18 Exhaust gas recirculation valve N345 Exhaust gas recirculation cooler change-over valve A Exhaust gas recirculation module B Vacuum unit C Catalytic conver ter An exhaust gas recirculation cooler allows the combustion temperature to be lowered further by cooling the recirculated exhaust gases. It also enables a greater quantity of exhaust gases to be recirculated. This effect is boosted further by the low-temperature exhaust gas recirculation system. The low-temperature exhaust gas recirculation system is explained on page 13 of this book.
Exhaust gas recirculation module On the 1.2l TDI engine, the exhaust gas recirculation valve and the exhaust gas cooler with exhaust gas flap have been combined in a single module. The advantages of the m odular design are a compact space requirement and, at the same time, a shorter control path. The exhaust ga s recirculation module is bolted to the exhaust side of the cylinder head and the exhaust manifold. The module is connected to the intake manifold directly through the cylinder head. This allows additional cooling of t he recirculated exhaust gases.
. Volksw age n AG
n AG a g e
w l k s V o
b y
e d i s r o h t u a
d oe
s n Exhaust gas recirculation o module t g
u a r a n t
Exhaust gas to intake manifold
s s e l n
u d
e e engine Exhaust gas from o
r a
c c
e p
t a
n y
e t t
l
i
i a b i l i
m r e
p
t y
t o
w i t
n
s
h
i ,
r
e l
s S465_042 p e
o h
e c
w
n
t t
Cooler
i
r
o
o
t
h e c
t
r
a p
o r r
n i ,
s
e
Exhaust gas recirculation valve
s
o p r
u p
e
c
Vacuum unit for exhaust gas flap
t
n
e
s s
o
f
i n f o r
l
a i
c r e
S465_005
m
a
m m
Design
t i o
o c r o
Exhaust gas e recirculation t a i r valve, closed v p r o f gas Exhaust g n i y from engine p
n i n
t h
Exhaust gas flap, open
i s d o c
u m
C
o
Curved disc
C . t h g
i r y p
o c
y b
d e t c e t o r P
Exhaust gas to intake manifold Coolant outlet
e n t .
Exhaust gas flap, closed
o y p r i g h t
b y
V l o k s w a g e n A
. G
Cooler
Exhaust gas recirculation valve, open
Coolant inlet S465_108
You will find further information on how the exhaus t gas recirculation system works in self-study programme no. 316 “The 2.0 ltr. TDI engine”.
47
Engine Management Diesel particulate filter system In addition to measures inside the engine, the carbon particles formed during combustion are reduced by a diesel particulate filter. The diesel particulate filter is located in one housing together with the oxidising catalytic converter. In the Polo, the housing has been positioned close to the engine so that the oxidising catalytic converter and diesel particulate filter reach operating temperature quickly.
Lambda probe G39 Pressure differential sender G505 Exhaust gas temperature sender 1 G235
Exhaust gas temperature sender 3 G495
Exhaust gas temperature sender 4 G648
G. Volksw age n AG g e n A d o e
w a l k s o
y V d b
s n
e i s r o h t u a
o t g u a r a n t
e e
o r a
s s e l
c c
e p
n
u d
t a
n y
e
t t i
m r e
l
i a b i l i
S465_109
p
t y
t o
System overview
w i t
n
s
h
i ,
r
e l
e s p e
o h
w
c
t t
n
i
o
r
o
t
h e c
t
r
a p
o r r
n i ,
e
c
s
t
n
e
e
s
s s
o p
o
r
u p
f
i n f o r
l
a i
m
c r e
a
m m
t
i o n i n
o c r o
t h i s o c
e t a v i r p r
Legend
u S465_110 m e n t
o f
g n
. C o p
i y
p
o
1 2 3 4 5 6
48
-
C . t h g
Control unit in dash panel insert J285 Engine control unit J623 Air mass meter G70 Diesel engine Exhaust gas temperature sender 1 G235 Turbocharger
d
i r y p
o c
y b
7 8 9 10 11 12
-
d e t c e t o r P
r y i g h t b V y
Lambda probe G39 l o k s w a g e n A Oxidising catalytic converter . G Diesel particulate filter Exhaust gas temperature sender 3 G495 Pressure differential sender G505 Exhaust gas temperature sender 4 G648
n AG a g e
w l k s o
y V d b
. Volksw age n AG
d oe
s n
e i s r
o
h t u a
o t g u a r a n t
e e
o r a
s s e l
c c
e p
n
u d
t a
n y
e
t t i
Design
l
i a b i l i
m r e
p
t y
t o
w i t
n
The diesel particulate filter consists of a honeycombed e l ceramic body, which is divided h ointo numerous small w channels. These channels are nsealed at alternating o ends and thus subdivided into inlet and outlet channels. i s
h
i ,
r
e s p e c
t t
i
o
r
t
h e c
t
r
a p
o r r
n
e
c
,
s
t
n
e
e
s
s s
o p
Function
o
r
u p
f
i n f o r
l
a i
m
c
r The exhaust gas, which contains ecarbon, flows m through the porous filter walls of m the intake channels. o c r o The carbon particles, unlike t he gaseous components e t a i of the exhaust gas, are deposited on v the filter walls of r p r o f the intake channels. g
a
t i o
n
i n S465_112 t h
i s d o c
u m
n i y
o
C . t h g
Regeneration
C
o p
p
i r y p
h t b y
o c
y b
r y i g
e n t .
d e t c e t o r P
V l o k s w
a g
e n A . G
To prevent the particulate filter from becoming blocked with carbon par ticles, thereby impeding its function, it must be regenerated on a regular basis. During the regeneration process, the carbon particles that have collected in the particulate filter are burned.
Passive regeneration
Active regeneration
During passive regeneration, the carbon particles a re continuously combusted without engine management system intervention. This mainly occurs at high engine loads and exhaust gas temperatures of 350°C-500°C.
In a large proportion of t he operating range, the exhaust gas temperatures are too low for passive regeneration. Since no more carbon particles can be oxidised passively, active regeneration is initiated by the engine control system as soon as a certain carbon level is reached in the filter. Secondary injections are used to increase the exhaust gas temperature to approx. 550°C - 650°C and the carbon particles are burnt to form carbon dioxide.
In this case, the carbon particles are converted into carbon dioxide via a reaction with nitrogen dioxide.
You will find detailed information on the diesel particulate filter system in self-study programme no. 336 “The catalytically coated diesel particulate filter” and no. 403 “The 2.0l TDI Engine with Common Rail Injection System”.
49
Engine Management Glow plug system A fast-start glow plug system allows the 1.2l TDI engine to be started without a long glow period in a way comparable with petrol engines. The glow plugs reach up to 1,000°C within 2 seconds thanks to an extremely short heating time. Therefore a “petrol engine-like” immediate engine start is p ossible in almost all climatic conditions.
System overview Engine control unit J623
Glow plug 1 Q10
Engine speed sender G28
Automatic glow period control unit J179 n AG a g e
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y V d b
Coolant temperature sender G62
e i s r o h t u a
s s e l n
u d
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.
Glow plug 2 Q11
AG d
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o t g u a r a n t
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Data bus diagnostic interface J533
c c
e p
t a
n y
e t t
Glow plug 3 Q12
l
i
Onboard r msupply e control t p unit J519
i a b i l i
Control unit in dash panel insert J285
o
n
t y
w i t
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w
c
Glow period warning lamp K29
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Automatic glow period control unit J179 e
e
s
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f
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a The automatic glow period control unit receives the information for the glow function from the engine control unit. c r m e a The start and duration m of the glow period, the activation frequency and the on-off ratio for the glow plugs are o m n o therefore determined by the engine control unit. c n r i
t i
i
t h i s d o c
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e t a v i r p
The automatic glow period control unit has the following functions: r
u m
o f
g n
i y
p
C a PWM . t h g
2. Integrated overvoltage and overtemperature shut-off 3. Individual glow plug monitoring - Detection of overcurrent and short-circuit in the glow circuit - Glow electronics diagnosis - Detection of an open glow circuit in the event of glow plug failure 50
C
o p modulated) r y i g h t b V y
1. Switching the glow plugs with signal (PWM = pulse-width i r y p - PWM low level = glow plug powered o c l o y k b s w d e a t g c e e t o - PWM high level = glow plug not powered n r A P . G o
e n t .
G. Volksw age n AG g e n A d o e
w a l k s o
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s n
e i s r
o
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Glowing
o t g u a r a n t
e e
o r
a c
s s e l
c
e p
n
u d
t a
n
y e t The steel glow plugs are activated by the engine control unit via the automatic glow period control unit J179 with i a b m r i e the aid of a pulse-width modulated signal (PWM signal). The voltage at the glow plugs is ad justed via the y p t w o i frequency of nthe PWM pulses. For rapid starting at outside temperatures below 18 °C, the maximum voltage of t h e e s to over 1,000°C within 11.5 V is applied for glowing. This high voltage guarantees that the glow plug is heated l p o e h a short time w (max. 2 seconds). This reduces the engine glow period. t i
l
l i t
s
i ,
r
c
t t
n
i
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r
o
t
h e c
t
r
Post-start glowing a p
o r r
n
e
i , s
c
t
n
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e By continuously reducing the on-off ratio of the PWM signal, th e voltage for post-start glowing is adjusted to the o s p o u rated voltage of 4.4V depending on the operating point. p s
s
r
f
i n f o r
l
a i
m
c r e
Post-start glowing is carried out for a maximum of 5 minutes after starting the engine o aup to a coolant temperature m m n o c of 18°C. n r t i
i
t h i s
o
e t a v i r p r
d
o c
u Post-start glowing helps reduce hydrocarbon emissions and combustion noises m during the engine warm-up phase. o f
g n
i y
C
o p
p
o
C . t h g
i r y p
r y i g
e n t .
h t b y
V l o k s w
o c
y b
e a t g c e e t o n A Phase-shifted activation of the glow plugs . G P
d
r
In order to relieve the burden on the onboard supply voltage during the glow phases, the glow plugs are activated phase-shifted. The falling signal edge always activates the next glow plug.
Glow plug
Cylinder 1 Cylinder 2 Cylinder 3 S465_119 Time (s)
51
Engine Management Start/stop system The 1.2l TDI engine fitted in the Polo Blue Motion comes with a start/stop system as standard. The start/stop system is used to reduce fuel consumption, exhaust gas emissions and n oise. The engine is automatically switched off when the vehicle is stationary and is automatically restarted when the driver wants to pull away. The start/stop function has been integrated into the engine control unit software. The system uses numerous signals from various sensors and vehicle systems to check the switch-on and -off conditions and operate the start/stop system. In certain operating situations and how often the engine is switched off depends on a wide range of factors. The basic requirement is that the comfort and safety of occupants must be maintained. If comfort and sa fety could be affected, the combustion engine will not be switched off even when the start/stop system is activated. If necessary, the engine will continue to operate the comfort- a nd safety-relevant components.
Start/stop operation button E693 n AG a g e
w l k s V o
y d b
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d oe
s n
e i s r
o
h t u a
o t g u a r a n t
e e
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t a
n y
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i
i a b i l i
m r e
p
t y
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w i t
n
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h
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e s p e
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c
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i
o
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t
h e c
t
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a p
o r r
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s
s s
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r
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l
a i
m
c r e
a
m m
t i o
n i n
o c r o
t h i s d o c
e t a v i r p r
u
m You will find detailed information on the start/stop system in e n g t n . i y C self-study programme no. 426 “Start/Stop System 2009”. p o o p
o f
C . t h g
i r y p
o c
y b
d e t c e t o r P
52
V
l o k s w
a g e n A . G
r y i g h
t b y
S465_118
d oe
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e d i s r o h t u a
Service
. Volksw age n AG
G e n A a g
w l k s V o
o t g u a r a n t
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s s e l n
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Special tools and workshop equipment u d
t a
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i
i a b i l i
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Description
r
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Tool/workshop equipment
w
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Application
c
t t
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a Pressure tester p n i VAS 6 551 , s e with adapter hoses s VAS 6551/1, VAS 6551/2, o p VAS 6551/3, VAS 6551/4, u p
For testing the low-pressure o fuel system e and the fuel pump c r r
t
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S465_117
u m
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o f
Puller T 10426
g n
C o injectors For removing p
i y
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o
C . t h g
i r y p
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y b
d e t c e t o r P
l o k s
w a g e n A G
.
r y i g h t b V y
S465_090 Adapter for camshaft fitting tool T 40094/12
For fitting the camshafts
S465_091
53
Test Yourself Which answer is correct? One or several of the given answers may be correct.
1.
Which statement about the fuel system pressurisation pump for the 1.2l TDI CR engine is correct? a) The fuel pump delivers the fuel from the fuel tank to the high-pressure pump at a pressure of approx. 1 bar. b) The fuel pump generates a pressure of approx. 6 bar in the fuel system supply line. c) The fuel pump is used exclusively to drive the suction jet pump in sw agtank. Volkfuel e n A G.the G e n A a g
w l k s
o y V
d oe
s n
d b
2.
e i s r
o
h t u a
o t g u a r a n t
e e
o
a engine? What is the purpose of the negative pressure in the fuel return of the injectors for the 1.2l TDI r CR c s s e l n
c
e p
u d
t a
n y
e t t
a) The negative pressure actuates the switching valves in the injectors.
l
i
i a b i l i
m r e
p
t y
t o
w i t
b) The negative pressure allows fast n opening and closing of the injectors. s i
h
,
r
e l
e s p e
o h
c) The negative pressure regulates w the high fuel pressure in the fuel system.
c
t t
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i
o
r
o
t
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r
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3.
o
n , pressure iregulated
How is the high fuel operating temperature?
s
r r
e
on the 1.2l TDI CR engine when the engine has reached
c
t
n
e
e
s
s s
o p
o
r
u p
f
i n f o r
l
a i
a) The high fuel pressure is regulated exclusively by the fuel metering valve. c r e m is fully closed. The fuel pressure regulating valve
m
a
t i o
m
n i n
o c r o
t h
i s d o c
t b) The high fuel pressure is regulated e exclusively by the fuel pressure regulating valve. a v i r The fuel metering valve is fully closed. p r o
f g n
i y
c) The high fuel pressure is regulated by regulating valve.
p
C . of actuation t h g o
both the fuel metering valve and
i r y p
o c
y b
d e t c e t o r P
4.
u m
e n t .
C
o p y the fuel pressure r i g h t b V y
l o k s w
a g e n A . G
What is the purpose of the knock sensor on the 1.2l TDI CR engine? a) The knock sensor is used to adjust the combustibility of the fuel for the start of injection. b) The signal from the knock sensor is used by the engine control unit to recognise the actual start of injection at the respective injector. c) The signal from the knock sensor is used by the engine control unit to recognise knocking combustion and sets the start of injection to late.
54
5.
Please fill in the missing terms:
y V
d b
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n AG a g e
w l k s o
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1 - .................................................................. 2 - ..................................................................
o c r o
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7 - ..................................................................
e t a v i r p
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8 - High-pressure accumulator (rail)
p
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3 - Fuel filter
m
S465_047
m m
C . t h g
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c u m
e n t .
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o p r y i g h t b V y
9 y - p .................................................................. o c l o y k b d e
t c e t o r P
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4 - ..................................................................
10 - ..................................................................
5 - ..................................................................
11 - ..................................................................
6 - ..................................................................
e l z z o n i r u t n e V - 1 1 2 3 N , 1 3 N , 0 3 N s r o t c e j n I - 0 1 7 4 2 G r e d n e s e r u s s e r p l e u F - 9 6 7 2 N e v l a v g n i t a l u g e r e r u s s e r p l e u F - 7 0 9 2 N e v l a v g n i r e t e m l e u F - 6 p m u p e r u s s e r p - h g i H - 5 1 8 G r e d n e s e r u t a r e p m e t l e u F - 4 e n i l y l p p u s l e u f r o f r o t a l u g e r e r u s s e r P - 2 6 G p m u p n o i t a s i r u s s e r p m e t s y s l e u F - 1 . 5 ; b . 4 ; a . 3 ; b . 2 ; b . 1 : s r e w s n A
55
