Iveco Daily. Manual

Checking diesel warming

It times operation of diesel warming in relation to ambient
temperature.

Checking cylinder position

During each turn of the engine, the control unit recognizes
which cylinder is in the power stroke and operates the
injection sequence for the appropriate cylinder.

Checking pilot and main injection timing

According to the signals from the various sensors, including the
absolute pressure sensor built into the control unit, the control
unit determines the optimum point of injection according to
internal mapping.

Checking injection pressure closed cycle

Depending on the engine load, determined by processing the
signals from the various sensors, the control unit operates the
regulator to obtain optimum line pressure.

Fuel supply

The fuel supply is calculated in relation to:

accelerator pedal position

engine speed

quantity of air introduced.

The outcome may be corrected in relation to:

the water temperature.

Or to avoid:

noise

smoke

overloading

overheating

turbine over-revving.

The delivery can be modified in the case of:

action of external devices (ABS), ABD, EDB

serious trouble decreasing the load or stopping the
engine.

After determining the mass of air introduced by measuring its
volume and temperature, the control unit calculates the
corresponding mass of fuel to inject into the relevant cylinder
(mg per delivery) also taking into account the temperature of
the diesel.
The mass of fuel calculated in this way is first converted into
volume (mm

per delivery) and then into degrees of throw,

or duration of injection.

Correcting flow rate according to water
temperature

A cold engine meets with greater resistance during operation:
friction is high, the oil is still very viscous, and the various
clearances are not yet optimized.
In addition, the injected fuel tends to condense on the metal
surfaces that are still cold.
The fuel supply for a cold engine is therefore greater than for
a warm one.

Correcting flow rate to avoid noise, smoke or
overloading

The behaviour that could lead to this kind of trouble is well
known.

The designer has therefore included special instructions in the
control unit to avoid it.

De-rating

In the event of the engine overheating, injection is modified,
decreasing the delivery to a varying degree, in proportion to
the temperature reached by the coolant.

Injection timing electronic test

The advance (start of delivery, expressed in degrees) may be
different from one injection to the next, also differentiated
from one cylinder to another. It is calculated, similarly to the
delivery, in relation to the engine load (accelerator position,
engine speed and air introduced).
The advance is appropriately corrected:

in phases of acceleration;

according to the water temperature.

And also to obtain:

lower emissions, noise and overloading;

better vehicle acceleration.

An extremely high advance is set on starting, depending on the
water temperature.
Feedback from the start of delivery is supplied by the change
in impedance of the injector solenoid valve.

Speed governor

The electronic speed governor has both features of
governors:

idling and top speed

all speeds

It is stable in ranges where conventional, mechanical governors
are imprecise.

Engine starting

During the first few turns of the engine, the timing and cylinder
no. 1 recognition signals (flywheel sensor and camshaft sensor)
are synchronized.
The accelerator pedal signal is ignored on starting. Starting
delivery is set only according to water temperature, by a
special map.
When the control unit detects such speed and acceleration of
the flywheel as to be able to consider the engine started up
and no longer driven by the starter motor, it re-enables the
accelerator pedal.

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Cut-off

This function cuts off fuel delivery when the vehicle is
decelerating (accelerator pedal released).

Cylinder balancing

Individual cylinder balancing contributes to increasing comfort
and handling.
This function permits individual, customized control over the
delivery of fuel and the start of delivery for each cylinder, even
differently from one cylinder to another, to compensate for
the hydraulic tolerances of the injector.

The differences in flow (delivery specifications) between the
various injectors cannot be evaluated directly by the control
unit. This information is supplied by Modus reading the bar
code of each injector at the time of assembly.

Synchronization search

If there is no signal from the camshaft sensor, the control unit
is anyhow able to recognize the cylinders into which the fuel
is to be injected.
If this occurs when the engine is already running, the
combustion sequence has already been acquired, so the
control unit continues with the sequence on which it has
already been synchronized.
If this occurs when the machine is at a standstill, the control
unit energizes a single solenoid valve. Within at most 2 turns
of the crankshaft, injection will take place in that cylinder, so
the control unit just needs to get synchronized on the firing
sequence and to start up the engine.

Cold starting

If even just one of the three temperature sensors (water, air
or diesel) records a temperature lower than 10

°C, pre-post

heating is activated.
When the key makes contact the pre-heating indicator light
comes on and stays on for a length of time that varies in
relation to the temperature (while the glow plugs in the
cylinder head heat the air), then flashes. It is now possible to
start up the engine.
When the motor is running this indicator light goes out, while
the glow plugs continue to be powered for a certain length of
time (variable) for post-heating.
If, with the indicator light flashing, the engine is not started up
within 20-25 seconds (inattention time), the operation is
cancelled so as not to run down the batteries pointlessly.
The pre-heating curve is also variable in relation to the battery
voltage.

Warm starting

If the reference temperatures all exceed 10

°C, when the key

makes contact the indicator light comes on for approximately
2 sec., for a short test, and then goes out. It is now possible to
start up the engine.

Run up

When the key makes contact, the control unit transfers the
information stored in memory when the engine was last
stopped into the main memory (see After Run) and makes a
diagnosis of the system.

After run

Whenever the engine is switched off with the key, the control
unit stays powered for a few seconds by the main relay.
This makes it possible for the microprocessor to transfer some
data from the main memory (volatile) to a non-volatile
memory, which can be erased and written over (EEPROM),
so as to make it available at the next start up (see Run Up).

These data basically consist of:

various settings (engine idling adjustment, etc.);

settings of some components;

fault memory.

The process lasts a few seconds, typically from 2 to 7
(depending on the amount of data to save), after which the
ECU sends a command to the main relay and makes it
disconnect from the battery.

It is extremely important for this procedure not to
be broken off, for example by switching off the
engine with the battery cut-out, or by disconnecting
the battery cut-out before 10 seconds have passed
since switching off the engine.
If this happens, the functioning of the system is
ensured, but repeated interruptions may damage
the control unit.

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87245

Figure 262

FUEL SUPPLY AND RECIRCULATION SYSTEM DIAGRAM

1. Injector fuel exhaust pipe - 2. Plug - 3. Electric injector - 4. Multiple pipe union - 5. Pressure regulator - 6. High pressure

pump CP3.2 with built-in feeding pump- 7. Fuel delivery pipe to high pressure pump - 8. Sensor for water presence in the fuel

filter - 9. Fuel filter - 10. Fuel return pipe to the filter - 11. Fuel inlet pipe from the reservoir - 12. Temperature sensor

connector - 13. Fuel return pipe to the reservoir - 14. Fuel filter clogged sensor - 15. Non-return valve - 16. High pressure fuel

delivery pipe to the hydraulic accumulator (rail) - 17. Pressure sensor - 18. High pressure fuel delivery pipe to the electric

injectors - 19. Hydraulic accumulator (rail).

High pressure fuel pipes

Low pressure fuel recirculation pipes

Check valve characteristics
opening pressure

0.5

bar

differential pressure less than 0.2 bar at 120 litres/h of fuel.

+ 0.05
- 0.1

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88619

Figure 263

Fuel pipes

OPERATION

In this injection system, the pressure regulator, located
upstream from the high-pressure pump, governs the flow of
fuel needed in the low-pressure system. Afterwards, the
high-pressure

pump

correctly

supplies

the

hydraulic

accumulator.

This solution, pressurizing solely the necessary fuel, improves
the energy efficiency and limits heating the fuel in the system.
The relief valve fitted on the high-pressure pump has the
function of keeping the pressure, at the pressure regulator
inlet, constant at 5 bars; irrespective of the efficiency of the fuel
filter and of the system upstream. The action of the relief valve
causes an increase in the flow of fuel in the high-pressure pump
cooling circuit.

The high-pressure pump continually keeps the fuel at the
working pressure, irrespective of the timing and the cylinder
that is to receive the injection and accumulates it in a duct
common to all the electro-injectors.

At the electro-injector inlet, there is therefore always fuel at
the injection pressure calculated by the electronic control unit.

When the solenoid valve of an electro-injector is energized by
the electronic control unit, fuel taken straight from the
hydraulic accumulator gets injected into the relevant cylinder.

The hydraulic system is made out of a low-pressure fuel
recirculation circuit and a high-pressure circuit.

The high-pressure circuit is composed of the following pipes:

pipe connecting the high-pressure pump outlet to the
Rail;

hydraulic accumulator;

pipes supplying the electro-injectors.

The low-pressure circuit is composed of the following pipes:

fuel intake pipe from the tank to the pre-filter;

pipes supplying the mechanical supply pump and the
pre-filter;

pipes supplying the high-pressure pump via the fuel filter.

The fuel system is also fitted with the fuel exhaust circuit and
the electric injectors.

According to the high performance of this hydraulic system,
for reasons of safety it is necessary to:

avoid connecting high-pressure pipe fittings with
approximate tightening;

avoid disconnecting the high-pressure pipes with the
engine running (NEVER try bleeding, which is both
pointless and dangerous).

The integrity of the low-pressure circuit is also essential for the
system to work properly; it is therefore necessary to avoid all
manipulation and modifications and act only in the event of
leakage.

HYDRAULIC SYSTEM

The hydraulic system is composed of:

tank

fuel pre-filter

electric supply pump

fuel filter

high pressure supply pump with supply pump built
inpressure regulator

manifold (rail)

electro-injectors

supply pipes and fuel recirculation

1. Fuel filter mounting - 2. High-pressure pump supply pipe

quick-coupling fitting — 3. Supply pipe quick-coupling fitting.

If disconnecting the fuel pipes (2-3) from the mounting (1), it
is necessary, when refitting, to make sure their fittings are
perfectly clean. This is to avoid an imperfect seal and fuel
getting out.

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Content .. 172 173 174 175 ..

Iveco Daily. Manual - part 174