Iveco Daily Euro 4. Manual — part 38
Figure 284
FUEL RECIRCULATION AND SUPPLY SYSTEM DIAGRAM
1. CP1 H high-pressure pump - 2. Pressure regulator - 3. Heated fuel filter with water separator - 4. Fuel delivery pipe to the filter - 5. Fuel return pipe to the tank - 6. Low-pressure pipe assembly - 7.
High-pressure delivery pipe to the hydraulic accumulator - 8. Pressure sensor - 9. Hydraulic accumulator - 10. Return pipe from the electric injectors to the low-pressure pipe assembly - 11.
High-pressure pipe between the hydraulic accumulator and the electric injectors - 12. Electric injectors.
high pressure
low pressure
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
hydraulic accumulator (rail);
-
hydraulic accumulator (rail);
-
pipes feeding the electric injectors from the hydraulic
accumulator.
The low-pressure circuit is composed of the following pipes:
-
fuel intake pipe from the tank to the filter;
-
pipe assembly made up of the following:
- feed pipe from the fuel filter to the high-pressure pump;
- fuel return pipe from the high-pressure pump to the tank;
- fuel exhaust pipe from the injectors to the fuel return pipe
to the tank.
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.
OPERATION
The pipes connected to the fuel filter support to the
low-pressure
pipe
assembly
are
of
the
quick-connect type.
Before fitting them, make sure the couplings and the
associated fittings on the mounting are clean.
NOTE
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109124
Figure 285
FUNCTIONAL DIAGRAM OF HYDRAULIC SYSTEM
1. High-pressure pump - 2. High-pressure delivery pipe - 3. Electric injector return pipe - 4. Electric injectors - 5. Common rail -
6. Fuel pressure sensor - 7. Filter with water separator - 8. Fuel electric pump non-return valve - 9. Injector return line
pressure-relief valve - 10. Tank - 11. Fuel electric pump - 12. Fuel electric pump intake filter - 13. Fuel electric pump
overpressure valve - 14. Pressure-relief valve - 15. Proportional pressure-relief valve.
Relative pressures within the circuit:
a.
4.15 bar
5.35 bar
b.
3.5 bar
5.0 bar
c.
p < 0.8 bar
d.
0.3 bar
0.8 bar
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Figure 286
HYDRAULIC SYSTEM
The hydraulic system is composed of:
-
tank
-
electronic fuel pump;
-
fuel filter;
-
high-pressure feed pump;
-
pressure regulator;
-
manifold (rail);
-
electric injectors;
-
low-pressure feed pipe assembly;
-
high-pressure pipes.
FUEL ELECTRIC PUMP ASSEMBLY SECTION
1. Return - 2. Connector - 3. Delivery - 4. Float - 5. Level sensor (+) - 6. Level sensor (-) - 7. Pump (-) - 8. Pump (+) - A.
Return line - B. Delivery line - C. Level sensor - D. Prefilter - E. Jet pump.
773010
Fuel pump
The fuel electric pump is of the volumetric, low-pressure type.
It is built into the fuel level indicator located in the fuel tank
Electric connector (2), located in the upper portion of the assembly, features the pins both for the electric pump and the level
sensor.
During the installation, the assembly shall not be stressed with axial loads of more than 67 N and torque of more than 3 Nm.
The maximum fastening torque on the gasket shall be 60 Nm.
Figure 287
109073
109123
CHARACTERISTIC CURVES
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4
Figure 288
542011
Fuel filter “UFIfilters”
Fuel filter (4) is made up of a filtering cartridge with water
separator, inside which electronic unit (6) is housed.
Water accumulation capacity is equal to 140 cm
3
.
Electronic unit (6) includes water present sensor, (optional)
filter clogging sensor and temperature sensor.
Water present sensor
Water present sensor detects water present in the filter
starting from 110 cm
3
volume present. Water present sensor
provides values of:
- low voltage in presence of water;
- high voltage in absence of water.
Characteristics
12V nominal voltage (8V minimum -16V maximum
Absorbed current:
- lower than 15 mA in rest conditions;
- lower than 150 mA in alarm conditions (including load).
Voltage on load:
- in rest conditions: higher than 11.8 V;
- in alarm conditions: lower than 3.9 V.
At key-on operation, the sensor makes a self-test issuing 2.5
second duration sound signal.
112723
Normally open contact type.
Operation differential pressure delta p: 0.8
bar
NTC temperature sensor
30 ˚C =
26.114 ohm
± 9.7%
0˚C =
5.896 ohm
± 7.3%
+25 ˚C =
2.057 ohm
± 5.6%
+60 ˚C =
596 ohm
± 3.8%
+100 ˚C =
186 ohm
± .2.0%
+110 ˚C =
144 ohm
± 2.4%
Temperature range: -40˚C to +130˚C
Heater
Nominal voltage
12 V
Maximum allowed voltage
30 V
Nominal power
250 W
Tightening torques
9.
Screw securing filter
1.5 + 0.5 Nm
4.
Water draining or air bleeding screw
1.5 + 0.5 Nm
+0,05
-0,5
1. Fuel filter support- 2. Diesel oil outlet - 3. Diesel oil inlet - 4. Diesel oil filter - 5. Drain screw - 6. Electronic unit - 7. Fastener -
8. 12-way connector - 9. Screw securing Diesel oil filter: H-G-B, water present sensor; - H-C, clogging sensor (if foreseen); -
D-E, NTC temperature sensor; - F-A, heater.
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