Iveco Daily Euro 4. Manual — part 33
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Figure 256
5432
COOLING
Description
The engine cooling system is the type with forced circulation
in a closed circuit. It comprises the following parts:
- An expansion tank whose plug has two valves
incorporated in it: an outlet and an inlet, which govern
the pressure of the system.
- A coolant level sensor at the base of the expansion tank.
- Only 136 HP, pressure switch (3), of normally closed
type (calibrated at 0.4 bar, absolute pressure 1.4 bar),
located on expansion tank and connected to EDC
central unit, protects engine against overheating caused
by cooling system failure. Where coolant temperature
exceeds 100 ˚C and contemporarily the pressure inside
expansion tank and it becomes lower than 0.4 bar, EDC
central unit reduces engine performance by changing
fuel flow rate (De-rating) until engine goes off.
- An engine cooling module to dissipate the heat taken
from the engine by the coolant with a heat exchanger
for the intercooler.
- A heat exchanger to cool the lubricating oil.
- A heat exchanger to cool the exhaust gases (engines
with EGR).
- A centrifugal water pump incorporated in the crankcase.
- An electric fan comprising an electromagnetic coupling
on whose shaft a hub turns idle that is fitted with an
axially mobile metal plate on which is mounted the
impeller.
- A 3-way thermostat governing the circulation of the
coolant.
Operation
The water pump driven by a poly-V belt by the crankshaft
sends coolant into the crankcase and with a greater head into
the cylinder head.
When the coolant temperature reaches and exceeds the
working temperature, it causes the thermostat to open and
the fluid is channelled from here to the radiator and cooled
by the fan.
The pressure in the system due to the change in temperature
is governed by the outlet (2) and inlet (1) valves incorporated
in the expansion tank filler plug (detail A).
The outlet valve (2) has a twofold function:
- to keep the system slightly pressurized so as to raise the
boiling point of the coolant;
- to discharge into the atmosphere the excess pressure
produced in case of high coolant temperatures.
The function of the inlet valve (1) is to permit transferring the
coolant from the expansion tank to the radiator when a
lower pressure is created in the system due to the reduction
in volume of the coolant as a result of its temperature
lowering.
Outlet valve opening 1
± 0.1 kg/cm
2
.
Inlet valve opening 0.005 — 0.02 kg/cm
2
.
108200
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CROSS-SECTION OF THE ELECTROMAGNETIC JOINT
Characteristics
Transmissible torque at 20
°C with clutch run in
45 Nm
Voltage
12 Volts
Power input
26 W
The electric fan control relay is activated or deactivated
according to the temperatures of: the engine coolant, the fuel
supercharging air and the pressure of the air conditioner fluid
(if present).
Coolant temperature
(if the sensor is not defective)
For 96/116 HP engines:
-
it activates at > 96
°C and deactivates at < 84°C.
For 136 HP engines:
-
it activates at > 102
°C and deactivates at < 90°C.
Turbocharging air temperature
It activates at > 75
°C and deactivates at < 65°C.
Fuel temperatures
(if the coolant temperature sensor is acknowledged to be
defective by the EDC control unit)
It activates at > 20
°C and deactivates at < 10°C.
With climate control system
With pressure in the system
it turns on
18.5
± 0.98 bar
it turns off
14.58
± 0.98 bar
75527
Figure 257
Figure 258
The water pump (3) cannot be overhauled. In case of coolant
leaking from the seal or damage, it must be replaced. The
water pump casing (1) is also used as a mounting for the
high-pressure pump. The seals (3 and 4) must always be
replaced.
75528
543212
Electromagnetic pulley
543210
Water pump
LONGITUDINAL CROSS-SECTION OF THE
WATER PUMP
1. Pump casing — 2. Pump drive shaft together with
bearing — 3. Seal — 4. Impeller.
Figure 259
75529
The by-pass thermostat (1) needs no adjustment.
If there is any doubt about its operation, replace it.
The thermostat casing is fitted with the thermometric
switch/transmitter and water temperature sensor.
A. — A1 Start of stroke at 78
°C ±2°C.
B.
Valve (1) stroke at 94
°C = 7 mm.
B1
Valve (2) stroke 94
°C, 6.4 mm
The stroke of 7 mm less than 60”.
543250
Thermostat
Figure 260
75530
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Figure 261
TURBOCHARGING DIAGRAM
Description
The
turbocharging
system
comprises
an
air
filter,
turbocharger and intercooler.
The air filter is the dry type comprising a filtering cartridge to
be periodically replaced.
The function of the turbocharger is to use the energy of the
engine’s exhaust gas to send pressurized air to the cylinders.
The intercooler comprises a radiator included in the engine
coolant radiator and its function is to lower the temperature
of the air leaving the turbocharger to send it to the cylinders.
108201
HOT AIR AT ATMOSPHERIC TEMPERATURE
COLD EXHAUST GAS
HOT COMPRESSED AIR
COLD COMPRESSED AIR
EXHAUST GAS
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