Iveco Daily. Manual — part 108
72600
Figure 255
The figure shows the high-pressure fuel flow through the
outlet ducts of the pumping elements.
1, 2 Fuel outlet ducts — 3. Fuel outlet from the pump with coupling for high-pressure pipe for the common rail.
Sec. A — A (Figure 253)
72601
F1A ENGINE
D
AILY
410
Base - May 2004
Figure 256
1. Solenoid — 2. Magnetic core — 3. Shutter cylinder —
4. Fuel inlet — 5. Fuel outlet.
When the engine control unit governs the pressure regulator
(via PWM signal), the solenoid (1) is energized that, in its turn,
generates the movement of the magnetic core (2). The shift
of the core causes the shutter cylinder (3) to move axially,
choking the flow of fuel.
75574
75575
1. Solenoid — 2. Magnetic core — 3. Pre-load spring —
4. Shutter cylinder.
When the solenoid (1) is not energized, the magnetic core is
pushed into the rest position by the pre-load spring (3). In this
condition, the shutter cylinder (4) is in such a position as to
offer the fuel the greatest section of passage.
Figure 257
Accurately clean high pressure pump.
Take off screws (2) and unthread pressure regulator (3) from
high pressure pump.
88406
Figure 258
Figure 259
88407
Accurately clean the seat (
→) of pressure regulator and the
connection surface (
→) of the regulator.
88408
Mount new seal rings (1 and 2) on pressure regulator (3) and
lubricate the rings with vaseline.
771034
Pressure control valve
The fuel pressure regulator is mounted on the low-pressure
circuit of the CP3 pump. The pressure regulator modulates
the amount of fuel sent to the high-pressure circuit according
to the commands received directly from the engine control
unit. The pressure regulator is mainly composed of the
following components:
-
connector
-
casing
-
solenoid
-
pre-load spring
-
shutter cylinder.
When there is no signal, the pressure regulator is normally
open, therefore with the pump providing maximum delivery.
The engine control unit, via the PWM (Pulse Width
Modulation) signal, modulates the change in fuel flow rate in
the high-pressure circuit by partially closing or opening the
sections of passage of the fuel in the low-pressure circuit.
Operation
Replacing pressure regulator.
For cleaning, do not use a tool which could damage
the surfaces and pay attention that impurities are
not introduced into channels.
NOTE
Figure 260
F1A ENGINE
411
D
AILY
Base - May 2004
Figure 261
Mount pressure regulator (1) on high pressure pump (2).
88409
88410
Screw up screws (1) and tighten them at 6
÷ 7 Nm (0.6 ÷ 0.7
kgm) torque.
Figure 262
MECHANICAL SUPPLY PUMP
Normal working condition
A. Fuel inlet from the tank — B. Fuel outlet to the filter —
1, 2 By-pass valves in closed position.
The function of the gear pump, mounted on the rear of the
high-pressure pump, is to supply the high-pressure pump. It is
governed by the shaft of the high-pressure pump.
In normal working conditions, the flow of fuel inside the
mechanical pump is shown in the figure.
Conditions of outlet overpressure
72592
Figure 263
Figure 264
72593
The by-pass valve (1) trips when overpressure is generated at
the outlet B. The pressure, overcoming the elastic resistance
of the spring of the valve (1), sets the outlet in communication
with the inlet via the duct (2).
Conditions of bleeding
72594
The by-pass valve (1) trips when, with the engine switched off,
you want to fill the supply system via the priming pump. In this
situation, the by-pass valve (2) opens, due to the effect of the
inlet pressure, and the fuel flows out via the outlet B.
Figure 265
Where pressure regulator is replaced on the engine
mounted on the vehicle, it is needed, after
replacement, to check that there are no fuel leaks
after an engine working period.
NOTE
Mounting operation must be performed keeping
the regulator perpendicular to connection plane
without angling it, in order not to damage seal rings
(1-2, Figure 260).
NOTE
F1A ENGINE
D
AILY
412
Base - May 2004
75576
Figure 266
774510
Hydraulic accumulator (rail)
The hydraulic accumulator is mounted on aspiration side
cylinder head.
Its task is to damp pressure oscillations caused:
-
the operation of the high-pressure pump;
-
the opening of the electro-injectors.
70500
Figure 267
1. Casing — 2. Plunger — 3. Stop — 4. Spring — 5. Direct
outlet to tank — 6. Seat on rail.
The pressure relief valve protects the system components if
the fuel pressure exceeds the setting: 1750 bars.
A. The tapered end of the plunger normally keeps the outlet
to the tank shut.
Figure 268
B.
If the pressure of the fuel in the hydraulic accumulator
exceeds 1750 bars, the plunger gets shifted and the
excess pressure is discharged into the tank.
70502
A
B
Overpressure valve (for forged hydraulic
accumulator)
1. Forged version hydraulic accumulator, inner volume ~
22 cm
3
- 2. Fuel pressure sensor - 3. Overpressure valve.
1. Welded version hydraulic accumulator, inner volume ~
23 cm
3
- 2. Fuel pressure sensor.
Figure 269
The electro-injectors have high-pressure supply (up to 1600
bar) and recirculation at atmospheric pressure, necessary for
the diesel used to operate the pilot valve.
The temperature of the diesel put back into circulation by the
electro-injector can get very high (approximately 120
°C).
The head of the electro-injector has a fitting for the electrical
connector.
They are mounted on the cylinder head and operated by the
injection control unit.
75588
Figure 270
775010
ELECTRO-INJECTORS
88418
F1A ENGINE
413
D
AILY
Base - May 2004
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