Iveco Daily. Manual — part 404

144

ELECTRIC/ELECTRONIC SYSTEM

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AILY

Base - May 2004

This is located on the high pressure pump and modulates the

fuel pressure to the rail (and thus to the injectors) on the

basis of the commands received from the electronic control

unit.
It mainly comprises:
- a ball shutter (1)
- a valve (3) control pin (2)
- a preloading spring (4)
- a coil (5)
When the solenoid is not energised, the delivery pressure

depends only on the spring preload.

When, after processing the various engine operating

parameters, the electronic control unit determines the need

for a different injection pressure, it modulates a command

signal in PWM to the regulator solenoid valve which

discharges the excess pressure in the pump backflow duct.
The modulated pressure is checked through the pressure

sensor on the rail by the control unit, which, if necessary,

suitably modifies the intensity of the command signal to

reach the required result.
The control solenoid valve (78013) is connected to pins 9

and 20 of connector A of the control unit.

PRESSURE REGULATOR CROSS SECTION

1. Ball shutter - 2. Ppin - 3. Valve - 4. Preloading spring - 5. Coil - 6. Body - 7. Anchor

3

2

5

4

7

6

1

Figure 150

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Pressure regulator (F1A)

Similar to the one installed on the 8140 engine and mounted

on the CP3 pump low-pressure circuit.
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 9 and 20.

1. Solenoid Ć 2. Magnetic core Ć 3. Cylinder Ć 4. Fuel input Ć 5. Fuel output Ć 6. Preloiad spring Ć 7. Connector

7

5

4

1

2

3

4

5

1

2

6

3

6

Figure 151

003386t

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ELECTRIC/ELECTRONIC SYSTEM

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Base - May 2004

The volume of the rail is small in size (29 cc) to allow quick

pressurising when starting, at idle speed and in the event of

high loads.
It has however sufficient volume to minimise the plenum

effect caused by opening and closing of the injectors and

operation of the high pressure pump.

Screwed onto the rail there is a fuel pressure sensor. The

signal sent by this sensor to the electronic control unit is

feedback information on the basis of which correct actuation

of the rail pressure is checked.

Common Rail for engines with serial numbers over 3089322
Temporary solution with simulated flow limiters and over pressure valve connected to the fuel discharge unit.

1

2

5

4

3

Common Rail for engines produced since end-October 2000
Final Common Rail solution without flow limiters and over pressure valve. The new Common Rail features different pressure

sensor layout and discharge unit connection predisposition.

1

2

3

4

5

1. Common Rail - 2. Simulated flow limiter - 3. Simulated over pressure valve seat - 4. Pressure sensor -

5. Fuel input from high-pressure pump

1. Common Rail - 2. To electrical injectors - 3. Pressure sensor - 4. Fuel discharge unit attachment -

5. Fuel input from high-pressure pump

Figure 152

Figure 153

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Rail (pressure accumulator - F1A)

The hydraulic accumulator is mounted in the cylinder head

on the side opposite aspiration.
Its some 22-cm

3

volume dampens fuel pressure oscillations

due to:

- high-pressure pump operation
- electro injector opening.
The fuel sensor and overpressure valve are positioned on

the hydraulic accumulator.

Over pressure valve
The over pressure valve protects system components in

the event that fuel pressure exceeds rated 1750 bars.
A The piston's conical end normally keeps discharge to

tank open.

B In the event of fuel pressure being over 1750 bars in

the rail, the piston is relocated and excess pressure is

discharged into the tank.

2

1

3

4

5

1. Common rail - 2. To electro injectors - 3. Fuel pressure sensor - 4. Overpressure valve -

5. Fuel input from high pressure pump

IVER PRESSURE VALVE

1. Body - 2. Piston - 3. Stop - 4. Spring - 5. Direct

discharge to tank - 6. Seat on the rail

Figure 154

Figure 155

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