Iveco Daily Euro 4. Manual — part 256
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ELECTRIC/ELECTRONIC SYSTEM
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When the engine control centre pilots the pressure
regulator via the PWM signal, solenoid (1) is activated, which
in its turn generates movement of magnetic core (2).
Core movement causes cylinder (3) axial displacement by
fuel delivery partialization.
When solenoid (1) is not activated, the magnetic core is
moved to its rest position by preload spring (6).
In these conditions, cylinder (3) is in a position to offer
maximum fuel passage cross-section.
Control electro valve 78013 is connected to centre
connector A pins 19 and 49.
1. Solenoid - 2. Magnetic core - 3. Cylinder - 4. Fuel input - 5. Fuel output - 6. Preloiad spring - 7. Connector
7
5
4
1
2
3
4
5
1
2
6
3
6
Figure 101
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The hydraulic accumulator is mounted in the cylinder head
on the side opposite aspiration.
By its volume, it damps fuel pressure oscillations owing to:
- high-pressure pump operation
- electro injector opening.
On hydraulic accumulator there is located the fuel pressure
sensor.
Pressure sensor
Fitted to a rail end, it measures fuel pressure present to the purpose of determining existing fuel pressure. Pressure value is used
to control pressure and determine injection electric control duration (85157).
It is connected to the central unit at pins A 8/43/28. It is fed at 5 V.
1. Rail - 2. Pressure sensor
PRESSURE LIMITER OPERATING GRAPH
1500 bar
0 bar
0.2V
0.5V
4.5V
4.8V
Minimum
1500 bar
0 bar
0.2V
4.8V
VOLTAGE
PRESSURE
Figure 102
Figure 103
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ELECTRIC/ELECTRONIC SYSTEM
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The solenoid valve controls the lift of the atomiser needle.
On the fuel inlet union a filter protects the injector for
impurities. The injector is constructively the same as
conventional ones, except that there is no needle return
spring.
Access to the injectors is gained by releasing the side
soundproof cover from the cylinder head. The fuel recovery
pipe has a quick coupling.
The injector comprises two parts:
- actuator - atomiser composed of pressure rod (1), pin (2)
and nozzle (3)
- control solenoid valve comprising a coil (4) and drive
valve (5).
1
st
phase: rest position
The coil (4) is not activated and the shutter (6) is in the closed
position.
The same fuel pressure acts in both the control area (7) and
in the pressure chamber (8), but as the shutter (6) is closed,
the needle (2) cannot be raised.
2
nd
phase: start of injection
The coil (4) is energised and causes the shutter (6) to move
upwards.
The fuel of the control volume (9) flows towards the backflow
duct (10) causing a drop in the pressure in the control area
(7).
At the same time, the pressure of the fuel in the pressure
chamber (8) causes the needle (2) to rise, resulting in fuel
injection to the cylinder.
3
rd
phase: end of injection
The coil (4) is not activated and makes the shutter (6) return
to the closed position, which re-creates a balance of forces
that makes the needle (2) return to the closed position and
consequently end injection.
Injectors (78247)
The solenoid valve is of the N.C. type.
The injectors are connected individually to the control unit at
the following pins:
- A16 / A47 cylinder 1 injector
- A2 / A31 cylinder 2 injector
- A1 / A46 cylinder 3 injector
- A17 / A33 cylinder 4 injector
INJECTOR WIRING DIAGRAM AND CROSS SECTION
1. Pressure rod - 2. Needle - 3. Nozzle - 4. Coil - 5. Pilot
valve - 6. Ball shutter - 7. Control area - 8. Pressure
chamber - 9. Control volume - 10. Backflow duct -
11. Control duct - 12. Supply duct - 13. Electrical
connection - 14. High pressure fuel inlet - 15. Spring
10
4
5
6
7
12
13
9
11
14
12
1
15
2
8
3
Figure 104
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This component incorporates a temperature sensor and a
pressure sensor.
It is fitted on the engine intake manifold (Figure 107) and
measures the maximum flow rate of the intake air which is
used to accurately calculate the amount of fuel to be injected
at each cycle.
It is connected to the control unit on pins A2 / A3 / A19 / A34.
Pin 1 sensor - Pin A23 ECU
-
earth -
Pin 2 sensor - Pin A53 ECU
-
temperature signal
Pin 3 sensor - Pin A13 ECU
-
5V - supply
Pin 4 sensor - Pin A40 ECU
-
0
÷ 5V
pressure signal -
Course of sensor in relation to the temperature:
Temperature
Resistance
- 40
°C
48.50 kOhm
- 20
°C
15.67 kOhm
0
°C
5.86 kOhm
20
°C
2.50 kOhm
40
°C
1.17 kOhm
60
°C
0.59 kOhm
80
°C
0.32 kOhm
100
°C
0.18 kOhm
120
°C
0.11 kOhm
Course of sensor in relation to the pressure:
See graph opposite.
AIR FLOW METER
1. Air flow meter location
2.5 bar
0.2 bar
0.4V
4.65V
VOLTAGE
ABSOLUTE PRESSURE
AIR FLOW METER OPERATING GRAPH
1
Figure 105
Figure 106
Figure 107
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