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938 views88 pages1.2 y 1.4 Tdi
dti
Uploaded by
Anonymous 5tkF5bFwOCopyright
© © All Rights Reserved
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Available Formats
Download as PDF or read online on Scribd
/ 88
Service GagD
Self-Study Programme 223
The 1.21 and 1.41 TDI engines
With Pump Injection System
Design and Function Following the successful launch of
191 4-cylinder TDI engines with unit injector
system in the Golf and Passal, the trend towards
economical, low-emission and simultaneously
powerful direct-injection turbodiesel engines is
continued in the Polo and Lupo by the 3-cylinder
TDI engine.
By eliminating a single cylinder, the engines are
now lighter, have fewer moving masses and
produce less friction than a 4-cylinder engine.
Despite their lower displacement, they have a
high performance potential for this vehicle class.
‘The Self-Study Programme describes the design and the
function of new developments! The contents are not updated!
Particularly in the 1.21 TDI engine developed
specially for the Lupo 3L, numerous new
technologies and production methods have been
‘employed in order to achieve the development
goal of reducing fuel consumption to 3 litres per
100 km. This consumption figure was made
possible by saving weight, reducing friction and
improving the combustion process.
In this Self-Study Programme, you have the
‘opportunity to familiarise yourself with this new
engine generation, which is exemplified by the
1.21 and 1.41 TDI engines.
* —
Oo ™"e
Please always refer to the relevant Service Literature
for all inspection, adjustment and repair instructions.
Literature. Contents
Introduction. ...... ese eeee ence een enee eee enee eee n ened
Engine mechanicals . .
Unit injector system .. 2.20... cece cece cece cece ence ee eeee 27
Fuel supply ...... 20. c0cececeeeeesecteceeeeseeseeeaen 38
Exhaust system .... 2.26.0 .0. eee e cece cece cece cence eee! 43
Engine management ........+2.s0ceeeeeeeeeeeeeeeeeeed 46 fe
Function diagram .........c0ceeeeseeeeseeeeeeeseeeeaen 70
Starter motor. ... 0... sees cece cece e eee eee eee eee 72
Engine management (special features of the Lupo 3L)....... 76
Service ..... 00s eeceeeeeecee ee ee eee neeeeeeeeeeeeeneeee 79 -
Test your knowledge. ........+2seeeeeeeeee eet e eter ee eee 85 Introduction
Installation variants
The 1.21 TDI engine is combined with the DS 085 electronic manual gearbox and is fitted
exclusively in the Lupo 3L
223.214 223.138 228.215
The 1.41 TDI engine is combined with 5-speed monual gearbox 021 and is fied in the Lupo, Polo and
Audi A2.
223.217
+ =
228218
23.216
223.219
You will find detailed information regarding Lupo 3L and Audi A2 in the following
@ _ Self-Study Programmes:
© No. 216 ,Lupo 3L Body"
© No. 218 ,Lupo 3L TOI"
No. 221 ,The DS 085 Electronic Manuel Gearbox"
© No. 239 ,Audi A2 - Body"
© No. 240 ,Audi A2 - Engineering”
© No. 247 ,Audi A2 - Engine and Gearbox" Designations and levels of
development of the engines
Both the 1.21 engine and the 1.41 TDI engine were
developed on the basis of the 1.91 TDI engine
without intermediate shaft and with unit injector
system. They belong to the EA 188 engine series
(EA=development order). As this designotion
often appears in specialist publications, we shall
now briefly explain the various diesel engine
series of Volkswagen.
The four-cylinder diesel engines are subdivided
into two series: the EA O86 series of swirl
chamber engines and the EA 180 series of direct
injection engine engines. A key feature of these
engine series is the intermediate shaft which
drives the oil pump and the vacuum pump.
The EA 180 engines were revised with the
introduction of the new A-platform class in 1996.
This gave rise to the EA 188 engine series.
This new engine series does not have an
intermediate shaft. The oil pump is driven by the
crankshaft by means of @ chain. The vacuum
pump is mounted on the eylinder head and is
driven by the camshaft. Further features of the
new engine series are the upright oil iter
housing, the coolant pump integrated in the
eylinder block and the pendulum support.
Further engine series are the 5-cylinder inline
engine series EA 381 and the V6 TDI engine
series EA 330 launched in 1997.
Engine series EA 180
Vacuum pump
Intermediate Shaft
Coolant pump
il pump
223.220
Engine series EA 188
Vacuum pump
Coolant pump
Upright
oil filter housing
Oil! pump.
228.164 Introduction
Specifications
223.24 228.26
Engine 121 TDI engine TAITDI engine
Engine code ANY AMF
Type Seylinder inline engine Seylinder inline engine
Displacement
TI91 em?
1422 cm?
Bore / stroke
765 mm / 86.7 mm
795 mm/ 95.5 mm
Compression ratio,
19.5:1
195:1
Firing order
1-2-3
1-2-3
Engine management
BOSCH EDC 15 P
BOSCH EDC ISP.
Fos!
Diesel min. 49 CN)
or biodiesel (RME)
Diesel min. 49 CN’
or biodiesel (RME)
Exhaust gas oftertreatment
Exhaust gas recirculation and
oxidation catalytic converter
Exhaust gas recirculation and
oxidation catalytic converter
Exhaust emission standard
‘Conforms to exhaust emission
level D4
‘Conforms to exhaust emission
level D3 Power output and torque
Performance diagram
un
Buses age
— Llengine Sport mode
— Ulengine FCO mode
© f000 2000 8000 40005000 [ml
223.010
Torque diagram
lensing Sport mods
tengo ECO made
eine
7000 2000 3000 4000 5000
em)
223.009
The maximum power output of the 1.41 TDI engine
is 55 kW at 4000 rpm.
The 1.21 TDI engine has two different
performance levels.
To achieve consumption figures of 3 litres per 100
km, the Lupo 3L has an Economy mode in which
engine performance is reduced by the engine
management system.
For a more sporty driving style, the engine can
be operated in the performance-oriented Sport
mode.
AAs the reference performance curve shows, the
maximum output of the 1.21 TDI engine is 45 kW
ct 4000 rpm. In Economy mode, maximum
power output is 33 kW at 3000 rpm
The 141 TDI engine develops 195 Nm of torque at
2200 rpm, hence the engine's high tractive
power and elasticity in the lower and medium
speed ranges.
When the 1.21 TDI engine is in Sport mode, the
maximum torque of 140 Nm is ovailable between
1800 rpm and 2400 rpm.
In Economy mode, maximum torque
is 120 Nm between 1600 and 2400 rpm.
As a result, high torque is available in the speed
range which is predominantly used. Engine mechanicals
The cylinder block
1.41 TDI engine
The 141 TDI engine has a gray cast iron cylinder
block.
1.21TDI engine
Cylinder liners
The cylinder block of the 1.21 TDI engine is
manufactured from an aluminium alloy te save
weight and minimise the fuel consumption of the
Lupo 3L.
The gray cast iron cylinder liners of the engine
are press-fitted and cannot be replaced.
The crankshaft bearing covers may not detached and the crankshaft may not be removed.
Undoing the bearing cover bolts causes the aluminium bearing seats to lose shape due to
relaxation of their inner microstructure.
@ _ Ifthe bearing cover bolts are undone, then the cylinder block has to be replaced
complete with the crankshaft. 223059
Threaded connection
with continvously
noo
#
~<
Conventional
threaded
connection
228.012
Cylinder head nut
oe
ol
eo Tension bolt
Crankshaft
a oi
@o
The tension bolt
Aluminium is not as strong as gray cast iron. If
the cylinder head in the cylinder block has a
conventional threaded connection, there is @
danger of the threaded connection coming
undone due to the high combustion pressures
which develop inside diesel engines.
For this reason, the cylinder head and the
cylinder block are bolted together by tension
bolls. The tension bolts permit a continuous flow
of force from the cylinder head to the bearing
cover, securely holding the engine together even
under heavy load. This makes for a secure
threaded connection and reduces the strain on
the cylinder block
Steel pins serve as tension bolts: they bolt the
aluminium cylinder block to the cylinder head
and the crankshaft bearing cap of the 1.2! TDI
engine.
They are securely glued into the cylinder block
with ,Loctide* locking fluid and cannot be
replaced.
During installation of the cylinder head, tightening of the cylinder head nuts puts o high
torsional strain on the tension bolts. To reduce the strain, the cylinder head nuts have to be
slackened. Please observe the instruction:
@
the Workshop Manual! Engine mechanicals
The balancing shaft
A balancing shaft is located in the engine's The upwards and downwards movements of the
crankshaft drive. Its task is to reduce vibration piston and conrod and the turning motion of the
and thereby ensure that the engine runs crankshaft produce forces which induce
smoothly. Vibrations. These vibrations are lransmitied
The balancing shaft is attached to aladder-type through the assembly mounting to the vehicle
frame and is driven by the crankshaft by means body. To reduce vibration, the balancing shaft
of a chain. It rotates at engine speed in the counteracts the forces of the piston, conred and
opposite direction to the engine. crankshaft.
Ladder-type frome
ne Crankshaft
Hydraulic
chain tensioner
Bolancing sheft
223.212
Counterweight
10 To be able to better understand the operating principle of the balancing shaft, several besic physical
terms are briefly explained on the following pages.
What is force?
The concept of "force" is derived from the tensing of muscles as experienced when lifting or pulling an
object. When o force acts upon a solid object, it can cause the object to become deformed, accelerate or
produce a counterforce of equal magnitude.
Other permutations are also possible.
Example:
‘When an apple is thrown, its accelerated by the effect of muscular power. The magnitude of the force
required to throw the apple is dependent on the apple's mass (weigh!) and acceleration.
In a drawing, the magnitude of a force, its direction of action and the point of application are
represented by an arrow.
Force = mass x acceleration
1 Engine mechanicals
Force due to weight.
Another form of force is force due to weight.
Due to gravitational acceleration, each body
moves towards the earth's surface and produces ]
@ force due to weight. The force due to weight is
dependent on the mass of a body and the
gravitational acceleration, and is generally
referred to as the force of attraction".
The greater the mass of the object, the greater =
the force due to weight.
223.086
Force due to weight = mass x gravitational
acceleration
What is torque’ Pivot
Ife force acting vertically on an object induces a Example:
rotational motion via a lever, this is referred to as
er the force nor the lever arm +—
g
product of both is referred to as torque. Torque
increases as a function of increasing force or 1 J
‘torque’. Since nei
lever arm length.
ae
clone determine the direction of rotation, the
(l= length) 223.195
Torque = force x lever arm
Example:
Two weights are located on a balance. Weight A is twice as heavy as weight B. On account of its higher
produces greater torque as than weight B and lifts weight B because of this. How do torques
cancel each other out?
Moments cancel each other out when the force
counteracis « force of equal magnitude at equal
distances from the pivot.
Example 1:
© Three weights are located on the balance
Weight A is on the left-hand side and weights
Bl and B2 are on the right-hand side.
As weights B1 + B2 are equally as heavy as
weight A, the force and counterforce cancel
each other out, i.e. force equilibrium exists.
or:
Moments cancel each other out when a
counterforce of half the magni
the force at twice the distance from the pivot.
ide counteracts
Example 2:
© Two weights are located on the balance.
Weight A is on the left-hand side and weight
Bis on the right-hand side. Weight B is
located twice the distance away from the
pivot. As a result, the torques on both pages
are equalised and a force equilibrium exists.
Engine mechanicals
Example
LEE EA
oo
iat
Example 2:
223.197
223.196
3 Engine mechanicals
SY
Inertia forces
Inertia forces occur in the engine's crankshaft drive. There are two types of inertia force: rotating inertial
forces and oscillating inertial forces.
Rotating inertia forces are produced by the
turning motion of the crankshaft (action of
centrifugal force)
rotation = orbital motion around own axis of
\
223.222
Oscillating inertia forces are produced by the
upwards and downwards movements of pistons
and conrods.
cxiltion = back and forward swinging motion
a
‘
223.257
How do inertia forces affect the 3-cylinder TDI
engine? t
When one observes the crankshaft of the
3cylinder TDI engine from the side, the crank
throws are uniformly arranged in relation to the
crankshaf's pivot. The throws are spaced 120°
part. As a result, the inerlia forces cancel each
other out.
223.182 Mass moments of inertia
Moss moments of inertia occur in the crankshaft drive of the 3-cylinder TDI engine since the inerfia forces
act upon the centre point of the crankshaft via different lever arms.
A-cylinder engine
The crankshaft of the 4-cylinder inline engine
appears symmetrical from the long side. The
crankshaft throws have the same distance in
relation to the centre point of the crankshaft,
As a result, the mass moments of inertia cancel
each other out.
3-cylinder engine
The crankshaft of the 3-cylinder inline engine is
not symmetrical, because the throws are different
distances away from the centre point of the
crankshaft. As a result, the mass moments of
inertia do not cancel each other out.
223.07
223.116
6 6
Engine mechanicals
How do the mass moments of inertia affect the
3-cylinder TDI engine?
The centifugal action of the rotating mass
moments of inertia induces @ circular wobbling
movement of the crankshaft about the
longitudinal axis.
The rotating mass moments of inertia are
compensated by counterweights on the Tst and
3rd throws of the crankshaft web. As there is not
enough space for a suitably large counterweight
Vibration absorber
NX
Crankshaft web
Longitudinal axis
i
|
| nt
223.223
in the crankcase of the 3-¢
der TDI engine,
additional weights are attached to the vibration
absorber and the flywheel.
Flywheel
228.224 The oscillating mass moments of inertia induce
a seesaw movement of the crankshaft about the
transverse oxis.
To compensate for this seesaw movement,
weights on the balancing shaft and the
crankshaft webs produce forces which counteract
the oscillating mass moments of inertia of the
crankshaft. They form two couples which
counterrotate at the same speed. The centrifugal
action produces two rotating moments. As soon
as the weights stand perpendicular to the
cylinder axis, the direction of action of two forces
is identical. The torques add up and, as a result,
are of equal magnitude fo the oscillating
moments of the piston and conrod.
In the direction of the transverse axis, the rotating
moments cancel each other out because the
rotating forces act in opposite directions due to
the counteropposed turning motion of the
crankshaft and balancing shaft.
Transverse oxis
223.205
203.226
°
223.207
v Engine mechanicals
—s
Repair notes:
For effective balancing of masses, the crankshaft. To maintain an even load on the chain, the
cand balancing shaft must converge inthe correct _ reduction ratio of the gears is configured in such
position. For this purpose, the marks on the ‘away that the marked chain links do not
crankshaft gear and balancing shaft gear must coincide with the marks until he engine has
be aligned with the two coloured links on the completed several revolutions.
drive chain when installing the drive chain,
Mork on crankshaft gear
Mark on belancing shaft gear
Please observe the instructions in the Workshop Manval.
8 Trapezoidal piston and
trapezoidal conrod
During combustion of the fuel-air mixture, a high
pressure is reached inside the combustion
chamber. The component ports of the crankshaft
drive are highly stressed due to the high
combustion pressure.
To reduce the strain on the piston and conrod at
high combustion pressures, the piston hub and
the conred eye are constructed trapezoidally.
In comparison with the conventional
connection between piston and conrod, the
contact surface of the conrod eye and piston
hub on the piston pin has been enlarged
Combustion force
Le
a
223.228
through its trapezoidal shape.
Therefore, the combustion forces are
distributed over a larger area. Less load is
placed on the piston pin and conrod.
oS
~
oS
Contact surfaces
/
223.014
Enlarged
contact surfaces 228.016
0 Engine mechanicals
The oil circuit
Vocuum pump
Oil spray nozzle for
Short-cireuit valve
Oil pressure
switch
Turbocharger Pressure
‘control valve
Hydraulic
chain
tensioner
Balancing shaft Oil non-retuen
Oil pump Pressure relief valve Oil cooler
valve
223.196
The pressure relief valve in the oil pump is a safety valve. It prevents damage to component parts of the
engine due to excessively high oil pressure, for example at low ambient temperatures and
high engine speeds.
The oil pressure control valve regulates the oil pressure of the engine. It opens as soon as the oil
pressure reaches the max. permissible value.
The cil non-return valve stops oil running back out of the cylinder head and oil filer holder and into the
cil sump when the engine is stationary.
The short-cirevit valve opens when the
to the engine.
ler is blocked and thereby safeguards the oil supply The oil filter holder
The oil filter holder is in an upright position.
Ithas @ paper filter element which can be
replaced from above and is therefore easy to
maintain and eco-friendly.
The oil pressure control valve and the oil
non-return valve ore integrated in the oil filter
holder. The short-circuit valve is located in the
sealing cover.
To ensure that oil drains out of the oil filter
housing and into the oil sump when replacing the
oil filter, «drilling is opened up when the paper
filter element is removed. Through this drill hole,
the oil can flow out of the filter housing via the
cylinder block and into the oil sump.
Paper filter
element
Oil drain hole
(opened up when
changing filter)
Oil non-retuen valve
Shortcircuit
valve
Oil pressure
control valve
223.230
21 Engine mechanicals
The oil pump
The oil pump is an internal gear pump and is
referred to as a duocentric pump. This concept
describes the geometric shape of the gearing of
the inner and outer rotors. The oil pump is
cottached to the ladder-type frame and is driven
by the crankshaft by means of a chain. The chain
is tensioned by a hydraulic chain tensioner.
Mechanical construction of
oil pump
\
Drive gear
Inner rotor
k >» Outer rotor
Housing cover
223.231
The pressure limiting valve in the oil pump is
a safety valve. It prevents damage to
component parts of the engine due to
excessively high oil pressure, for example at
low ambient temperatures and high engine
speeds.
Pressure limiting valve
223.232
22 This is how it works:
Priming
The inner rotor is mounted on the input shaft and
drives the outer rotor.
Due to the different rotational axes of the inner
and outer rotors, the teeth diverge during the
rotational movement producing an increase in
volume on the suction side. As a result, the ol is
drawn in along an intake line and conveyed to
the pressure side
Producing pressure
On the pressure side, the teeth of the inner and.
outer rotors re-mate. This results in a decrease in
volume between the teeth, forcing the oil into the
engine's oil circuit.
Oil sump
Oil sump.
Pressure side
Suction side
Intake line
223 108
Pressure side
Suction side
223.108
23 Engine mechanicals
Coolant circuit
On 1.21TDI engine, the oil cooler is integrated in the large coolant circuit. Hence, the engine quickly
reaches its operating temperature, helping fo improve the fuel economy of the Lupo 3L.
Heat exchanger for
121 TDI engine Expansion tank \
heating
Cooler for
Ci cooler *NO¥s 988 recirculation
BB large cool
Small cooling circuit
Coolant pump/
coolant thermostat
223.280
The oil cooler on the 1.41 TDI engine is located in the small coolant circuit.
Heat exchanger for
141 TDI engine Expansion tank —
=O heating
[~
}) — Oil cooler
Coolant pump/
coolant thermostat
TB barce coating circuit
Small cling cr
223.281 The toothed belt drive
Large drive forces are necessary to produce an
injection pressure of 2000 bar. These forces
place a heavy load on the component parts of
the toothed belt drive,
For this reason, the following measures should
be taken to relieve the load on the toothed belt:
Vibration absorber
Avvibration absorber in the camshaft
gear wheel reduces the vibrations in the
toothed belt drive.
223.233
To set the port timing, there is
‘a mark on the toothed belt
Solen
——— valve stem
High-pressure
Injector solenoid
chamber
223.014
31 32
Unit injector system
Commencement of pre-injection cycle
The pump piston is pressed down by the injection,
cam via the roller-type rocker arm, and thus
displaces the fuel from the high-pressure
chamber into the fuel supply line.
The engine control unit initiates the injection
cycle. For this purpose, the engine control unit
activates the injector solenoid valve.
Injection com
High-pressure
chamber
The solencid valve stem is pressed into the seat
and closes off the path from the high-pressure
chamber to the fuel supply line. As a result,
pressure begins to build up inside the high-
pressure chamber. At 180 bar, the pressure is
greater than the force of the injector spring.
The injector needle is lifted and the pre-injection
cycle commences.
P_—Pomp piston
Solenoid valve seat
Solenoid
valve stem
Fuel supply line
Injector needle
223.015 Injector needle damper
During the pre-injection cycle, the stroke of the injector
needle is damped by a hydraulic ,cushion". This makes it
possible to meter the injection quantity exacily.
This is how it works:
During the first third of the overall stroke, the injector needle
is opened undamped and the pre-injection quantity is
injected into the combustion chamber.
‘As soon as the damping piston plunges into the drill hole in
the injector housing, the fuel can only be displaced above the
injector needle via a leak gap in the injector spring chamber.
This produces a hydraulic ,cushion* which resiriels the stroke
of the injector needle during the pre-injection cycle.
+— Undamped
stroke
223.165
Injector spring
chamber
Injector housing
Leak ap
Hydraulic
cushion"
Damping piston
223.166
33 Unit injector system
End of pre-injection cycle
The pre-injection cycle ends directly after the The pre-injection cycle is completed.
injector needle opens. The rising pressure causes The downwards movement of the bypass piston
the bypass piston to move down, thereby increases the preload on the injector spring.
increasing the volume of the high-pressure The fuel pressure required to reopen the injector
chamber. needle during the subsequent main injection
The pressure drops briefly as a result and the cycle, therefore, is higher than during the
injector needle closes. pre-injection cyele.
+
High-pressure
chamber
— Bypass piston
——— Injector
spring
Injector needle
223.016
34 Commencement of main injection cycle
Shortly after the injector needle closes, the
pressure again rises inside the high-pressure
chamber. The injector solenoid valve remains
closed and the pump piston moves downwards.
‘At approx. 300 bar, the fuel pressure is greater
than the force of the preloaded injector spring.
The injector needle is again raised and the main
injection quantity is injected.
High-pressure
chamber
The pressure rises up to 2050 bar, because more
fuel is displaced inside the high-pressure
chamber than can escape through the nozzle
holes. Peak pressure is at maximum engine
power output, i. at a high engine speed and
lorge injection quantity.
Pump piston
Injector solenoid
valve
Injector spring
Injector needle
223.07
35 Unit injector system
End of main injection cycle
The injection cycle is terminated when the engine _The injector needle closes and the bypass piston
control unit no longer actuates the injector is pressed into its intial position by the injector
solenoid valve. The solenoid valve stem is spring.
opened by the solenoid valve spring and the fuel
displaced by the pump piston can escape into The main injection cycle is now completed.
the fuel supply line. The pressure drops.
Pump piston
Solenoid valve — Solenoid valve stom
spring
— Injector solenoid
— Bypass piston
— Fuel supply line
Injector needle
223.017
36 The fuel return line in the unit
injector
The fuel return line in the unit
following tasks:
jector has the
© Cooling the unit injector. For this purpose,
fuel is flushed from the fuel supply line through
the ducts of the unit injector and into the fuel
return line.
© Discharge of the leaking fuel from the
pump piston.
© Separation of vapour bubbles from the fuel
supply via the restrictor into the fuel return
line.
Leaking fuel —__
Restitor
__— Pump piston
Fuel return line
Fuel supply
223.032
7 38
Fuel supply line
The fuel system
The fuel is drawn out of the fuel tank through the fuel filter by « mechanical fuel pump and pumped
long the supply line in the cylinder head to the unit injector (on the 1.41 TDI engine, an electrical fuel
pump pumps the fuel from the fuel tank to the mechanical fuel pump).
The fuel pre-heating valve
‘On the 1.21TDI engine, the fuel pre-heating valve does not open,
Up the path fo the fuel rank uni the fuel temperature exceeds
{60°C (LAI TDI engine >30°C). As a result, the heat is
concentrated on the engine and the engine reaches operating
temperature more quickly
\ sy
The fuel cooler
coolthe ering loth lok not /
expotad exes het fol
Thou iter |
bre nion sen aginstotra |
and weor which canbe cused by
pares ond wae |
223.243,
These
‘operates os a pre-supply pump and
pumps fuel fo the mechanical
fuel pump.
prevents fuel flowing back from the fuel pump into the fuel
tonk when the engine is stationary
(opening pressure=02 bar}
223.260 The fuel which is not required for injection flows from the unit injector back into the fuel tank along the
return line in the cylinder head, the fuel pump and the fuel cooler.
rare sensor The pressure
ting valve
is used for fuel temperature ‘mointoins a constant pressure of I arin the fuel return line. Tis results in a force
measurement by the engine control unit, equilibrium atthe solenoid valve stem.
The bypass
Ie there is ie in the fual system - this can
‘occur, for example, when the fuel tank is
run empty - the pressure limi
19 valve
remoins closed, The incoming fuel expels
_ 1g fuel expel
the oir from the system.
203244
iP f 7 | me enero
223.48
The fuel pump
The prossure limiting valve The strainer
seo he fs ssrein te el py The haste ak of electing vapour bubbles inthe foe
valve opens at a fvel pressure of 75 bor and the fuel is ‘upon: Teo bubbles ae sparc wo the
dalivered fo the suction side ofthe fuel pump. ‘eticor bore andra ines
39 40
Fuel supply
The fuel pump
Vecuum pump
The fuel pump is located directly behind the
vacuum pump on the cylinder head. It draws the Fuel pump
fuel out of the fuel tank and feeds it to the unit I 2
injector. \gn! \
Both pumps are jointly driven by the camshaft, i
hence this unitis referred to as a !
standem pump" Fuel return line UC
/ oe _ |
Fuel supply °
Connection for
pressure gauge
Manuel.
The fuel pump is a blocking vane-
cell pump. One of the
characteristic features of this
pump type is that the blocking
vanes are pressed against the
rotor by a spring force. This has
the advantage that the fuel pump
delivers fuel even at low engine
speeds. The fuel ducting within
the pump is designed in such a
way that the rotor is kept
constantly wetted with fuel - even
when the tankis empty. Automatic
priming is thus possible.
ae
There is a connection on the fuel pump for pressure gauge VAS 5187, which can be used to
check the fuel pressure in the supply line. Please follow the insiructions in the Workshop
Prossure regulating valve for
Blocking vane
fuel feed 8
Connection for
fuel supply line
From the return
line in the
cylinder head
____Roter
—~__ Restrictor
Strainer
In the supply line in the
cylinder head
Connéction for
fuel return line Prossure regulating valve for
fuel return line
223.129 The distributor pipe
There is distributor pipe in the supply line in the
cylinder head. It has the task of distributing the
fuel evenly to the unit injectors.
223.120
Cylinder 1 Cylinder 2 Cylinder 3
Cylinder head
| Annular gap
Gross holes Distributor pipe
223131
This is how it works:
Fuel from unit injedor
The fuel pump feeds the fuel into the supply line
in the cylinder head. Here, the fuel flows towards Fuel to unit injector
cylinder 1the along the inner side of the SS
distributor pipe. The fuel enters the annular gap
between the distributor pipe and the cylinder
head wall through cross holes. Here, the fuel is annular 90
mixed with the hot fuel pushed back into the
supply line by the unit injectors. This results in @
constant fuel temperature in the supply lines to
all cylinders. All unit injectors are supplied with
the same fuel mass. This ensures that the engine
runs smoothly.
Mixing of fuel in the
228.132
4 42
Fuel supply
The electrical fuel pump
The electrical fuel pump is located in the fuel tank and functions as a pre-supply pump.
It pumps fuel to the mechanical fuel pump on the cylinder head. This ensures that vapour bubbles cannot
form in extreme situations due to excessively high vacuum in the fuel supply (e.g. driving at high speed at
warm ambient temperatures). Irregularities in engine running due to vapour bubble formation are thus
prevented.
is how it works:
Electrical principle
When the ignition is turned on, the fuel pump
relay is activated by the engine control unit and
switches the working current for the fuel pump.
The pump runs for approx. 2 seconds and builds
up ¢ pilot pressure. During the pre-heating
phase, the pump is switched off in order to
relieve the load on the starter battery. The pump
runs continuously as soon as the engine begins
toturn.
Hydraulic principle
The fuel pump draws the fuel out of the reservoir
through 4 filter.
The fuel feed is proportioned in the pump cover.
(One part is fed into the supply to the engine and
the other part is fed into the suction jet pump.
drive. The suction jet pump draws the fuel out of
the fuel tank and pumps it into the fuel pump's
reservoir. The pressure limiting valve in the pump
cover limits the feed pressure to 0.5 bar.
This protects the fuel lines from exposure to
excessively high fuel pressures.
Pressure limiting
valve el supply line
Feel 2007 Oe Eset rtum ino
Electrical
fuel pump
Suction jot pump Fuel tank
{entrainment pump]
me 228 206 The fuel cooling system
The high pressure in the unit injectors causes the ducts through which the returning fuel flows in
fuel to heat up to such a high degree that it has loop.
to be cooled before it flows back into the fuel The fuel is cooled by ambient air flowing along
tank. the cooler, protecting the fuel tank and the fuel
For this purpose, a fuel cooler is located below level sender against exposure to excessively high
the vehicle underbody. It has several parallel fuel temperatures.
“
223.245
Fuel cooler
Fuel from engine
Fuel to
fuel tank
223.212
43 44
Exhaust system
The exhaust systems of the 1.21 TDI and 1.4I TDI engines differ mainly in respect of their weight, as well as
number and layout of the catalytic converters and silencers.
Exhaust system of the 1.21 engine
The exhaust system of the 1.21 TDI engine
comprises a primary catalytic converter, a main
catalytic converter and a main silencer.
The primary catalytic converter is the smaller of
the two and is positioned near to engine. As a
result, the catalytic converter reaches its
‘operating temperatur eerly. Only a small silencer
is required on account of the engine's small
displacement. For weight reduction reasons, the
wall thicknesses of the exhaust pipes are
reduced.
Rear silencer
223.1490
Exhaust system of the 1.4l engine
The exhaust system of the 1.41 TDI engine is of
conventional design. It comprises a catalytic
converter, © middle silencer and o rear silencer.
CTX Main catalytic converter
Central silencer
Rear silencer
203.49 The EGR cooler
The 1.21 TDI engine has a cooler for exhaust gas
recirculation. This cooler is located between the
intake manifold flap housing and the exhaust
manifold. Cooling the recirculated exhaust gases
reduces the combustion temperature and
nitrogen oxide emission.
This is how it works:
The EGR cooler is connected to the coolant
circuit. To enlarge the cooling surface, the metal
body (heat sink) is channelled in @ honeycomb-
like pattern. Coolant flows through these
channels. The recirculated exhaust gos flows past
Coolent
Cooling fins
Exhaust gas
from
exhaust manifold
22801]
the channels and dissipates the heat into the
coolant.
The cooled exhaust gas reduces the combustion
temperature still further and causes additional
reduction of the nitrogen oxides.
Exhaust gos
to intake menifold
Coolant connection ‘
203.20
45 Engine management
System overview
Sensors
Holl sender G40.
Engine speed
sender G28
Accelerator for pedal position
sender G79
Kick-down switeh F8
Idling speed switch F60
Air-mass flow meter G70
Coolant
temperature sender G62
Clutch pedal switch F36"
(14171 only)
Intake manifold pressure
sender G71
—=>
Intake monifold tomperature &
sensor G72
Broke light switch F
cand brake pedal switch F47
Fuel
Atitude sender F96
Self diagnosis
leod and
immobiliser lead
Control
display unit in
dash panel insert 1285
ABS control unit /104 Diesel direct
injection system
control unit J248
>
CAN databus
Electronic manual gearbox
control unit J514
High heat output
Actuators
Unit injactor valves,
cylinder 1-3
N240-N242
Charge pressure control
solenoid valve N75
EGR valve NIS
Intake manifold flap =
change-over valve =
N239
Glow period warning
lomp K29
Glow plugs Q6
Additional heating
heater element Z35
223.008
a7 Engine management system
Sensors
‘Camshaft
Hall sender G40 sender rotor
= “ The Hall sender is attached to the toothed belt
Lo
“S ET > guard below the camshaft gear wheel.
It scans seven teeth on the camshaft sender
wheel, which is attached to the camshaft gear
wheel.
203.246
Signel utilisation The engine control unit uses the signal from the
Hall sender for cylinder recognition when
starting the engine.
Effects of signal foilure If the signal fails, the control unit utilises the
signal from engine speed sender G28.
Es
(K) s28
OO
G40
pec
DC
223.035
48 Cylinder recognition when
starting the engine
‘When the engine is started, the engine control
unit needs to know what cylinder is in the
compression stroke in order to activate the
corresponding injector solenoid valve. To obtain
this information, the engine control unit evaluates
the signal from the Hall sender. The Hall sender
scans the teeth on the camshaft sender wheel
and thus determines the position of the camshaft.
The camshaft sender wheel
As the camshaft performs one 360° revolution
per working cycle, there is ene tooth for each
cylinder on the sender rotor. The interval
between teeth is 120°.
To be able to assign the teeth to the cylinder, the
sender rotor has an additional tooth for cylinder
Vand 2. These teeth are different distances apart.
This is how it works:
Each time a tooth posses the Hall sender, this
generates a Hall voltage, which is transmitted to
the engine control unit.
From the different intervals between the signals,
Signal pattern, Hall sender
Cylinder 1
120°
Cylinder 2 223.036
the engine control unit recognises the cylinder,
and hence can activate the corresponding
injector solenoid valve.
120° 120°
To
223.096
49 Engine management
The engine speed sender G28
Engine speed sender wheel
Md
: 203 247
Signal utilisation
Effects of signal
50
The engine speed sender is inductive sender. It is attached to
the eylinder block
The engine speed sender scans a 60-2-2-2 sender rotor which is
attached fo the crankshaft. The sender rotor has 54 teeth around
its circumference and 3 gaps of 2 teeth.
The gaps are offset by 120° and serve as reference marks for
determining the crankshaft position.
The engine speed and the exact pesition the crankshaft are
determined using the signal from the engine speed sender.
The injection point and the injection quantity are computed on
the basis of this information.
IF the signal from the engine speed sender fails, the engine is
shut off. It is not possible to restart the engine. Fun
n the quick start recognition feature To facilitate a quick start, the engine control unit evaluates
the signals from the Hall sender and the engine speed
sender.
The engine control unit recognises the cylinder from the
signal from the Hall sender which the camshaft sender
wheel scans. As there are 3 gaps on the crankshaft sender
rotor, the engine control unit receives a reference signal
after every one third crankshaft rotation. The engine
control unit can thus recognise early the position of the
crankshaft and activate the corresponding solenoid valve
in order to initiate the injection cycle.
Signal pattern, Hall sender / engine speed sender
2 Vidiv= 20 ms/div.
1Comshaft
| Holl sender
Sie is
Cylinder 2 Cylinder 3
Duo
Cylinder 1
i
Engine speed sender
oa TN
1 Crankshof rotation 223.097
51 Engine management system
Accelerator position sender
The accelerator position sender has been
developed into a compact accelerator pedal
module. On the new accelerator pedal module,
the potentiometers are actuated directly and not
via a cable pull. As a result, itis no longer
necessary to adjust the accelerator pedal
position sender after installation. The exterior
mechanical construction of the senders identical
to that of the accelerator pedal module of the
electrical throttle control used in petrol engines.
203248
The following components are i
the accelerator pedal module:
- © «accelerator position sender G79,
© idling speed switch F&O and
@ kick-down switch F8,
223.259
The sensors comprise sliding contact paths and
slip contacts. The slip contacts are mounted
fogether on a shaft.
228.188
52 Signal uti
Effects of signal failure
Electrical circuit
Accelerator position sender G79
is a sliding contact potentiometer. After every change in
accelerator pedal position, the resistance changes. From this, the
‘engine control unit recognises the actual accelerator pedal
position and uses the information as a main influencing variable
for computing the injection quantity
Idling speed switch F60 and kick-down switch F8 are slidi
contact switches. When the switch is open, the sliding contact
paths are interrupted and the resistance is infinite. If the switch is
closed, the resistance along the sliding contact paths is constant.
9
Idling speed switch F0 indicates to the engine control unit thet
the accelerator pedel is not depressed
Kick-dewn switch F8 informs the engine control unit when the
accelerator pedal is depressed past the full-throttle stop. In the
Lupo 3L with electronic manual gearbox DSO85, this signal is
utilised for the kick-down function.
Without this signal, the engine control unit cannot determine the
accelerator pedal position. The engine continues to run at an
increased idling speed to enable the driver to reach the next
workshop.
223.189
Foo FB. G9
53 Engine management system
The following sensors were previously described in other Self-Study Programmes on TDI engines. For this
reason, they are explained here in less detail than in the previous SSPs.
Air-mass flow meter G70
The air-mass flow meter with reverse flow recognition
determines the intake cir mass. Itis located in the intake pipe.
The opening and closing movements of the valves cause the air
mass drawn into the intake pipe to flow backwards.
The air-mass flow meter with reverse flow recognition recognises
the returning air mass and makes allowance for this in the signal
it sends to the engine control unit. As a result, the air mass
measurement is highly precise.
Signal utilisation The engine control unit uses the measured values to calculate the
injection quantity and the exhaust gas recirculation rate.
es Effects of signel failure If signal the from the air-mass flow meter fails, the engine
control unit uses « fixed default value.
Coolant temperature sender G62
The coolant temperature sender is located on the coolant
connection of the cylinder head. It informs the engine control
unit about the actual coolant temperature,
223.081
Signal utilisation The engine control unit uses the coolant temperature as a
compensating value for computing the injection quantity.
Effects of signal failure IF the signal fails, the engine control unit uses the signal from the
fuel temperature sender as o default valve.
54 Intake manifold pressure sender G71
Intake manifold temperature sender G72
228043
Intake manifold pressure sender
G71- Signal utilisation
Effects of signal failure
Intake manifold temperature sensor
672 - Signal utili
Effects of signal failure
The intake manifold pressure sender and the intake manifold
temperature sensor are combined as a unit located in the intake
pipe.
The signal from the intake manifold pressure sender is required
to check the charge pressure. The engine control unit compares
the calculated value with the set value from the charge pressure
mop. If the actual value deviates from the set value, then the
‘engine control unit adjusts the charge pressure via the charge
pressure control solenoid valve. =
Its no longer possible to control the charge pressure.
The engine has less power.
The engine control unit requires the signal from the intake pipe
temperature sender as a compensting value for computing the
charge pressure. Thus, allowances are made for the effect of
temperature on the density of the charge air.
If the signal fails, the engine control unit uses a fixed default
value. This can result in a loss of performance.
55 56
Engine management system
The altitude sender F96
Alitude sender The altitude sender is located in the engine control unit.
Signal utilisation The altitude sender indicates the actual ambient air
pressure fo the engine control unit. This valve is dependent
on the vehicle's geographical altitude. With this signal, the
engine control unit makes an altitude-based correction for
charge pressure control and exhaust gas recirculation.
Effects of signal failure Black smoke occurs at high altitudes.
Clutch pedal switch F36 ‘The clutch pedal switch is located on the pedal assembly.
(on 141TDI engine only)
From this signal, the engine control unit recognises
whether the clutch is engaged or disengaged. When the
clutch pedal is depressed, the injection quantity is reduced
for a short time. This prevents engine shudder when
changing gear.
Ifthe signal from the clutch pedal switch fails, then load
change jolts can occur during gearchanges.
Effects of signal Brake light switch F and
The brake light switch and the brake pedal switch are combined
‘a5 a unit located on the pedal assembly.
Both switches supply the engine control unit with the
“brake operated signal. As the accelerator position sender
could be defective, engine speed is limited for safety reasons
when the brake is depressed.
Effects of signal failure IFone of the two switches fails, the engine control unit reduces =
the fuel quantity. This results in loss of engine power.
Fuel temperature sender G81
The fuel temperature sender is a temperature sensor with a
negative temperature coefficient (NTC). The means thet the
resistance of the sensor decreases with increasing fuel
temperature. The fuel temperature sensor is located in the fuel
return line from the fuel pump to the fuel cooler and determines
the actual fuel temperature.
223.093,
Signal utilisation To allow for the density of the fuel at different temperatures, the
‘engine control unit requires the actual fuel temperature in order
to compute the commencement of injection point and the
injection quantity.
7 Wed
58
Engine management
CAN databus signals
The Lupo 31 is fitted with electronic manual
gearbox DS085. This gearbox performs
gearshifs automatically and thereby makes it
possible to operate the vehicle in the most
economical gear in any driving situation.
The gearbox control unit and the engine control
unit exchange a large volume of information
across the CAN databus. The gearbox control
unit uses this information to calculate gear shifts:
the engine control unit to control engine torque
output.
The following examples clearly show how data is
transferred between the engine control unit and
gearbox control unit.
223 284
© The gearbox control unit uses the information
supplied by the engine control unit - such os
engine speed, engine torque, engine load and
accelerator pedal position - to compute the
gear selection.
© The gearbox control unit informs the engine
control unit about gear changes in order to
prevent the engine rewing-up when the clutch
is open.
© IF the engine is to be shut off using the STOP/
START function, the gearbox control unit sends
the message “engine off”. The engine control
unit now disconnects the power supply to the
unit injector valves. Data are also transferred across the CAN
databus between the engine control unit, the
control unit in the dash panel insert and the
ABS control us
@ The engine control unit transfers the engine
speed for the rev counter and the
consumption signal for the fuel consumption
displaytothecontrol unitinthedashpanelinsert.
© For engine braking control (EBC), the ABS
control unit sends a command to increase
engine speed fo the control unit. This prevents
the driven wheels locking on slippery road
surfaces if the driver quickly releases the
accelerator pedal.
223.249
39 60
Engine management system
Actuators:
ctor valves
N240-N242.
Commencement of injection
point
Injection quentity
Effects of failure
The unit injector valves are attached to the unit injectors with @
cap nut. They are solenoid valves which are activated by the
engine control unit. The commencement of injection point and
the injection quantity are regulated by the engine control unit
via the unit injector valves.
As soon as the engine control unit activates an injector solenoid
valve, the solencid valve stem is pressed into the seat by the
magnetic coil and shuts off the path from the fuel supply to the
jigh-pressure chamber of the unit injector. The injection cycle
then commences.
The injection quantity is defined by the solenoid valve's
activation period. Fuel is injected into the combustion chamber
as long as the injector solenoid valve is closed.
IF an injector solenoid valve fails, the engine will run rough and
have less power. The injector solenoid valve has two safety
functions. If the valve stays open, pressure cannot be built up in
the unit injector. If the valve stays closed, the high-pressure
chamber of the unit injector can no longer be filled. In both
cases, no fuel is injected into the cylinder.
223.089 The following actuators were previously described in other Self-Study Programmes on TDI engines.
For this reason, they are explained here in less detail than in the previous SSPs.
Solenoid valve for charge pressure control N75
2
The charge pressure control solenoid valve is an electro
pneumatic valve. It switches the control pressure fo actuate
the vacuum box for vane adjustment (1.21 TDI engine) or
the charge pressure control valve (L4l TDI engine).
28.185
Charge pressure control of the 1.21 TDI engine
The 1.21 TDI engine has a variable turbine geometry.
The exhaust gas flow onto the turbine rotor is controlled by
the adjustable guide vanes. This ensures quick response at
low engine speeds. The back pressure in the exhaust is
reduced in the part-throttle range. The result is high
bottom-end torque and low fuel consumption.
223.250
Charge
pressure
contral
solenoid
valve
Vacuum box for
vone adjustment
Guide vanes The charge pressure is controlled
according to a map stored in the engine
control unit. For this purpose, the
charge pressure control solenoid valve
is activated by the engine control unit.
The control pressure used to actuate the
vacuum box for vane adjustment is
defined in dependence on the signal's
Chorge air
cooler
Vacuum pup
a Exhoust gas
Cy
[= Atmospheric pressure
[ZZB Control pressure
pulse duty factor. The exhaust gas flow
onto the turbine rotor is controlled by
the guide vanes. The control pressure is
produced from atmospheric pressure
and vacuum
223.200 Engine management system
Charge pressure control in the 1.41 TDI engine
223.251
The 1.41 TDI engine achieves its high torque with
a non-variable turbine geometry.
Charge pressure contral valve
Charge air cooler
Charge
pressure
control
solenoid
valve
Exhaust gos.
[== Atmospheric pressure
= Charge pressure
[EEE Control pressure
223.199
The charge pressure control solenoid valve is
activated by the engine control unit.
The control pressure used fo actuate the charge
pressure control valve is defined in dependence
cn the signal's pulse duty factor. The flow rate of
Effects of failure
the exhaust gas ducted to the turbine rotor to
drive the turbocharger is thus controlled.
On the 141 DI engine, the control pressure is
produced from atmospheric pressure and charge
pressure,
IF the charge pressure control solenoid valve
foils, engine performance will be reduced. Exhaust gas recirculation valve N18
The EGR valve is an eleciro-pneumatic valve. Itis
located in the engine compartment on the engine
bulkhead and switches the control pressure used
to actuate the EGR valve.
Exhaust gas recirculation is a way of reducing
nitrogen oxides in the exhaust gas. A portion of
the exhaust gases is added to the intake ai.
The oxygen level in the combustion chamber and
the combustion temperature are thus reduced recirculated because « high oxygen level is
The lower combustion temperature reduces required for effective power utilisation in the
nitrogen oxide emission. When the vehicle is combustion chamber.
operating at full throttle, no exhaust gas is
This is how it works:
EGR valve Exhaust gas
® recirculation vole =
Vacuum pump
EGR cooler
Ta Exhaust gas
——— i
1 Atmospheric pressure
TEES Contrel
Exhaust gas recirculation is controlled by a map stored in the engine control unit.
For this purpose, the engine control unit activates the EGR valve. The control pressure used fo actuate the
EGR valve is defined in dependence on the signal's pulse duty factor. The quantity of recirculated
exhaust gases is thus regulated,
223.201
Effects of failure Exhaust gas recirculation is not assured. Engine management system
Intake manifold flap change-over
valve N239
The intake manifold flap change-over valve is located in the
engine compartment in the vicinity of the air-mass flow meter.
It switches the vacuum for actuating the intake manifold flap in
the intake pipe. It prevents the engine from jolting at shut-off.
Diesel engines have a high compression ratio.
The high compression pressure of the induced air acts on the
crankshaft via the piston and conrod and causes the engine to
jolt ot shut-off
S
XO)
Pr
CLARY,
The intake manifold flap disconnects the air supply when the
223052 engine is turned off. As a result, only @ small amount of air is
compressed and the engine smoothly runs to a halt.
This is how it works:
fe 223.053, IF the engine is turned off, the engine control unit sends a signal
to the intake monifold flap change-over valve. The change-over
valve then switches the vacuum for the vacuum box. The vacuum
box closes the intake manifold flap.
Effects of failure If the intake manifold flap change-over valve fails, the intake
manifold flap remains open.
Electrical circuit
naw
223.054 Glow period warning lamp K29
The glow period warning lamp is located in the dash
panel insert.
Ithas the following tasks:
@ | indicates to the driver that the glow plug system is
203.252 active prior to starting the engine. The warning lamp is,
lit during the glow period.
© [there is o fault in a component with self-diagnostic
capability, the warning lamp flashes.
Effects of
The warning lamp is it and does not flash. A fault
message is stored in the fault memory. Engine management
Function diagram 30
Components ®
F Broke light switeh
F8 —Kickdown switch
F36 Clutch switch (*1.41 TDI only)
FAT Broke pedal switch
F60 Idling speed switch
628 Engine speed sender
G40 Hall sender
662 Coolant temperature sender
670 Air-moss flow moter
G71 Intake manifold pressure sender
G72 Intake manifold temperature sender
G79 Accelerator poston sender
GB1_ Fuel temperature sender
452 Glow plug relay
J24B_ Diesel direct injection system control
nit
4317 Voltage supply relay
41359. Low heo! ouput relay
1360 High heot output lay
NIB EGRvahe
N75. Charge pressure control solenoid valve
Ge
N75
1N239_Intoke manifold flop change-over valve
N240_No. | cylinder unit injector solencid valve
N241_ No. 2 cylinder unit injector solenoid valve
N242_ No. 3 cylinder unit injector solenoid valve
Q6 Glow plugs (engine)
235 Additional heating element 30
+ 5
337
+ 452
sq s
cel Ae
bm o IB
F
HI ll Ul [|
1248) —
| [lee] Fe He =
G62 240] Naar) N22 Fso FB cn
209.006
Auxiliary signals
A Brake lights, L_ Glow period control
B Fuel consumption signal M_ — CAN-Bus-Low
€ Engine speed signal N- CAN-Bus-High
D Air conditioner compressor curoff © Terminal DF
E Air conditioner compressor-readiness Input signal
= Output signal
F Road speed signal — Positive
H Cooling fan run-on — Earth
K Diagnostic ond immobiliser wire — CAN dotabus Engine management
Glow plug system
The glow plug system makes it easier to start the
engine at low ambient temperatures. The glow
plug system is activated by the engine control
nit at a coolant temperature of less than +9°C.
The engine control unit activates the glow plug
relay. This relay then switches on the working
current for the glow plugs. The system
overview shows what sensors utilise signals
for the glow plug system and what actuators
are activated
Overview of glow plug system
Engine speed sender
G28
Coolant temperature
sender G62 @&
Engine control unit J248
\ Glow plugs 06
Glow plug relay J52
Glow period
223.056
The glow cycle is subdivided into two phases.
Pre-heating phase
After the ignition is tumed on, the glow plugs are
activated at « temperature of below +9°C. The
glow period warning lamp comes on. At the end
of the glow cycle, the warning lamp goes out and
the engine can be started.
id
Afterglow ps
Engine start up is followed by an afterglow
period, regardless whether pre-heating has
taken place or not. This reduces combustion
noise, improves idling quality and reduces
hydrocarbon emission. The afterglow phase lasts
no more than three minutes and is interrupted
when the engine speed exceeds 2500 rpm. The additional heater
On account of its high efficiency, the engines
develop little waste heat. Available heating
capacity may be too low.
In countries with a cold climate, therefore, an
additional heating element is installed in the
heater box.
This heating element is located in the air stream
behind the heat exchanger.
The additional heating element comprises
corrugated-fin type aluminium contact plates
and fifteen ceramic PTC resistors subdivided into
three heating elements. It heats the passing cir
flow and thus ensures that the passenger cabin
heats up quickly.
PTC resistors are at their most conductive when
they are cold. They have a positive temperature
coefficient (PTC). This means, the resistance of the
PTC thermistor increases with rising temperature,
thus reducing the current flow.
Heat exchanger
Additional heating element
223.127
_ Air stream
Heat exchanger
s Additional heating element
223.160
PIC resistor
Silicon profile section
Corrugated-fin type
aluminium contact plates
208125 Engine management system
Heat output control
Approx. 10 seconds after the engine is started, The three heating elements are activated and
the additional heating element of the diesel deactivated in stages by the engine control unit
injection system control unit is activated, via the high and low heat output relays,
depending on demand and engine load.
To activate the heating element, the following
conditions must be met:
Position of the rotary push-button between
80%-100% heat output
Contact switch opened as of 80% heating output
Intake cir less than 19°C / coolant temperature
less than 80°C
Battery voltage greater than TV
S-phase AC alternator load factor less than 55%
(signal from terminal DF)
“ Engine speed greater than 450 rpm
~
I
You will find detailed information regarding the additional heating
element in Self-Study Programme No. 218 ,The Lupo 3L TDI".
223.126 The stop/start function T Dp i
In Economy mode, the stop/start function of the
Lupo 3L is activated in order to avoid
unnecessary fuel consumption. For this purpose,
the engine is shut off during stationary phases.
The pages marked with
the TDI symbol explain the
functions and engineering
ofthe Lupo 3L
The following conditions must be met so that the engine stops
avtomatically 222.40
© The selector lever isin position E.
er de ie active. pa
conomy mode is active coo
@ The broke pedal is held for 3 seconds.
© Broke pressure is above 4 bar.
@ The ABS wheel speed sensors signal that the vehicle is stationary. ——
© Coolant temperature is above 17°C.
@ The alternator load factor is below 55%.
Vehicle operation ean resume when the fellowing conditions are met:
@ The broke pedal is released.
© The gearbox control unit starts the engine.
@ The gearbox control unit activates the clutch.
@ The driver depresses the accelerator pedal and the vehicle
accelerates. Starter motor
The starter motor
The starter motor of the Lupo 3L has a control
unit which controls the starting operation
Basically, the storter motor equivalent is
designed as a bendix-drive starting motor with
planetary gear. The service life of the starter
motor has been extended by the numerous
starting cycles due to the STOP/START function.
This was achieved by reinforcing the mechanical
components of the starter motor and modifying
the electrical control.
Starter motor
Sprocket
gear
Meshing spring
Electrical control
The starter motor control unit is mounted on
the housing, It controls the meshing operation.
Wear of the starter pinion and starter
TDI
Mechanical reinforcements
Brushes extended
© Meshing spring reinforced
© Engaging lever is carbon-fibre reinforced
© Storter sprocket gear widened
Starter moter control unit
223.253,
sprocket gear is reduced by soft, time-controlled
meshing of the starter pinion in the starter
sprocket gear.
The starter motor and starter motor control unit can only be replaced together. This is how it works: T D I
The starting cycle is initiated by the gearbox
control unit. For this purpose, the gearbox control
unit activates the starter inhibitor relay. The relay
switches the current to the starter motor control
unit. The control unit regulates the current flow
for the starter pinion meshing operation.
The starting cycle is activated either by means of
the STOP/START function, or in the conventional
manner by turning the ignition key in the
ignition switch.
Electrical cirevit
A: Battery
d
SSS SS SS B: Starter motor
D: Ignition switch =s
453: Starter motor relay
J514: Electronic manual gearbox
control unit
1514
AS: Starter motor control unit
228.00 i i Md
Starter motor
Phase 1
In the first phase, the current rises. A magnetic
field is built up in the pulling coil and the pulling
cormature picks up.
Phase 2
After the idle motion of the engaging lever has
been overcome, the current flow from the control
unit is reduced for approx. 10 ms until the starter
pinion makes contact with the starter sprocket
gear. This reduces the pre-engagement speed of
the starter pinion by a factor of 4 and ensures
soft pre-engagement which reduces starter
pinion wear.
TDI
Pulling coil ——_
Pulling
‘armature
Sprocket gear 223,255} Meshing relay Contact bridge
Current curve
TDI
In the third phase, the current rises again.
The starter pinion meshes with the sprocket gear
ct the same time.
Phase 3
Phase 4
The last phase is initiated by the closing of the
contact bridge in the meshing relay. As a result,
the starter motor starts up and turns the engine
crankshaft via the sprocket gear. The holding
current is maintained until the engine has
started.
Currant intensity (A)
228.009
Time (s) Engine management system
Engine starting safety concept T Dp J
As already explained on page 4, the Lupo 3L has an electronic manual
gearbox. The gearbox control unit computes the gear changes and
controls the STOP/START function. To prevent uncontrolled movement
of the vehicle during the starting operation, several conditions have to
be observed when starting the engine.
can only be started in the STOP and N positions of the selector
In the STOP position of the selector lever
the Ist gear or reverse gear is engaged in the gearbox.
To start the engine, the clutch must be opened or the gearbox engaged in the 223167
neutral position. Therefore, the foot brake must be pressed when starting the
engine in order to prevent uncontrolled movement of the vehicle.
For this purpose, the gearbox control unit receives the "brake operated" signal
from brake pedal switch F47 via the engine control unit. 223.169
P Neve
In selector ley
F po:
.. the gearbox is in idling mode. To prevent the vehicle from rolling away, the
handbrake should be securely applied.
223-168
Safety condition when starting in Economy mode
If the vehicle is in Economy mode, the engine is not started by the STOP/START
function when the driver's door is open. This measure serves fo prevent
uncontrolled movement of the vehicle when the driver exits the vehicle.
{As long as the foot brake is operated, the driver can return to normal STOP/START
operation by closing the door).
The gearbox control unit receives the "door open' or "door closed” signal from
door contact switch F2.
23.170 Acoustic signals T D I
As an additional safety precaution, a gong signal sounds in the
dash panel insert in order to alert the driver to the following
situations:
© When the driver's door is opened when a drive position is selected
and the engine is running. The signal ensures that the driver does
not exit the vehicle while the engine is running and thus prevents
uncontrolled movement of the vehicle. As the clutch is engaged up
to the slip point, the vehicle displays a tendency to "creep"
@ When the engine is shut down by the STOP/STARTfunction and the
driver's door is opened, The signal indicates that the engine will not
be started in the usual manner by the STOP/START function when
the foot brake is released The engine must be started in the
STOP or N position of the selector lever.
© When the vehicle is being driven with the handbrake applied.
© When the vehicle is held on gradients for a lengthy period of time
while a drive position is selected. In tuation, the clutch slips,
because it is engaged as far as the slip point in order to ensure a
good response to gear changes.The clutch is opened when it
becomes too hot due to overloading. The signal alerts the driver to
the danger before the clutch opens and the vehicle rolls away.
© |f gearshifis are activated very frequently while driving, The signal
indicates that cn unnecessarily large amount of fuel is being
consumed and that the hydraulic system is under heavy strain Engine management
Idling speed control
To save fuel, the idling speed of the 1.2itre TDI
engine is regulated differently when the vehicle is
travelling and when it is stationary.
When the vehicle is stationary, the idling speed is
reduced to 850 rpm for comfort reasons.
When the vehicle is travelling, the idling speed
reduced to 770 rpm. This saves fuel and reduces
pollutant emissions.
For idling speed control, the engine control unit
differentiates between a travelling vehicle and a
stationary vehicle at a road speed of >13 kph.
The engine control unit receives information on
vehicle speed from road speed sender G22 vie
the control unit for the dash panel insert.
TDI Service
Notes on tow starting and towing.
The following conditions must be met in order to tow start the
Lupo 3L:
© Switch ignition on.
© The battery must be charged. The gearbox has on
electro-hydraulic system. It operates only when
sufficient battery charge is avcilable.
© Engage the selector lever in the N position,
© Keep tow starting speed above 6 kph so that
the selector lever lock is not active.
© When towing speed is reached, shift the
selector lever into position E.
@ Deactivate the Eco mode so that the engine does not shut off
automatic after stopping.
The following conditions must be met in order to tow the
Lupe 3L:
© The battery must be charged.
@ Engage the selector lever in the N position.
@ IF the gearbox is not in neutral, then the vehicle must be
towed with front axle raised.
© Do not exceed a towing speed of 50 kph
TDI
223_158a 10 9 Service
Self-diagnosis
The self-diagnosis procedure is started with
address word 01 ,Engine electronics". In self-
diagnosis mode, the diesel direct injection system
control unit provides the following functions and
is able to communicate with the Vehicle
diagnostic, testing and information system
VAS 5051:
Funetion Address
word
Interrogate control unit version 01
Interrogate fault memory 02
Actuator diagnosis 03
Basic setting 04
Clecr fault memory 05
End of output 06
Encode control unit o7
Read data block 08
Please follow the relevant instructions in the Workshop Manual.
228.159 Engine oil
As of model year 2000, new service engine oils
are required for engines with "Long Life Service"
and for the diesel engines with unit injector
system. These engine olls have the specification
0W30 and therefore have a lower viscosity than
the engine oils used previously. Further
The engine oil standards for the 1.21 TDI and
the 1.41 TDI engines are different.
The 1.21 TDI engine must be filled with the oil
conforming to VW standard 50600. This oil is
also used in the diesel engines with "Long Life
Service”. It has special idling properties and
therefore helps to improve fuel economy.
The 1.41 TDI engine is filled with oil suitable for
engines with unit injector. This oil meets VW
standard 50501.
Also refer to the note:
»Maintenance interval extension’,
advantages are their higher thermal load
tolerance and enhanced cleaning properties.
To account for the high loads produced by
driving the unit injector elements, the oils for the
diesel engines with unit injector system also have
high shear strength.
VW 50600 for the 1.21 TDI engine
(Lupe 31)
223.101
VW 50501 for the 1.41 TDI engine
223.101
the repair literature and Self-Study Programme No. 224 Service
Special tools
Designation
Tool
Use
10008 marking plate
For fixing the hydraulic toothed
belt tensioner in place when
instolling and removing the
toothed belt.
10050 crankshaft stop
. ¢ 223.092
For fixing the crankshaft to the
crankshaft gear wheel when
‘adjusting the port timing.
10051 counter-holder for
camshaft ger whee!
For installing the camshaft gear
wheel.
10052 pulling-off device
for camshaft gear wheel
223.088
For detaching the camshaft gear
wheel from the camshaft taper.
10053 assembly fixture
for crankshaft sealing ring
®
223.087
Guide sleeve ond compression
sleeve for fiting the crankshaft
sealing ring.
T10060 drift
223.162
For arresting the tensioning
device for the ribbed V-belt Special tools
Designation
tool
Use
110054 alignment
bracket set
For fiting the fast
‘clamping block of the unit injector.
ing bolt of the
10055 pulling-off device
for unit injector olement
223.09)
For pulling the unit injector out of.
the cylinder head.
T 10056 assembly sleeve
for O-rings
223.090
For fiting the O-
injector,
198 of the unit
VAS. 5187 pressure gauge
223.086
For checking the fuel supply
pressure on the fuel pump.
T1061 socket insert
223.161
For undoing ond tightening the
cylinder head nut as well as the
fastening bolt for the
counterweight Test your knowledge
1. The balancing sheft has the following tasks:
4) It reduces the vibrations of the engine crank drive and ensures that the engine runs smoothly.
Bb) It compensates for fluctuation in engine idling speed.
«) It drives the vacuum pump.
2. The tension bolts in the 1.21 TDI engine...
are steel pins which are used to bolt the aluminium cylinder block, the cylinder head and the
crankshaft bearing cover.
b) ... are steel pins with which the camshaft bearings are anchored in the aluminium cylinder head.
¢) «are securely glued into the cylinder block and cannot be replaced.
3. The exhaust gases which are recirculated in the intake manifold are cooled in order...
«@) ... fo reduce the thermal load on the catalytic converter.
b) ... fo reduce the combustion temperature.
€) «to reduce nitrogen oxide formatuously.
4, In what state does the electrical fuel pump run continuously?
@) As soon as the engine turns.
b) As soon as the engine has started
€) As soon as idling speed is reached. 5. What statement applies to the charge pressure control system for the 1.41 TDI engine?
©) The charge pressure control solenoid valve is activated by the engine control unit.
b) The engine hot a variable turbine geometry.
¢) The control pressure for actuating the charge pressure control valve is generated from the
atmospheric pressure and vacuum.
6. What is the task of the starter motor control unit on the starter of the 1.21 TDI engi
) It controls the starting operation and thus minimises starter pinion wear.
b) It automatically initiates the starting eycle and shuts off the engine as required.
¢) Itserves as an anti-theft device and is activated by the engine control unit for this purpose.
7. In what selector lever position can the 1.2! TDI engine in the Lupo 3L be started?
€@) In selector lever position N.
b) In selector lever position STOP.
¢) In any selector lever position Solutions
aBpajmouy inoA jsay Notes For intral use only © VOLKSWAGEN A, Wollsbura
lights roterved, Technical peciicabone subject to change without notice
(040:28104220 Tachnicol satus 05/00
® This papers produced from
‘on-