Engine Iveco Vector 8. Manual — part 9

Figure 18

Rail (pressure accumulator)

1. Common rail (one for each row) — 2. Flow limiters — 3. Fuel inlet from the high—pressure pump (one for each common

rail) — 4. Pressure sensor — 5. Pressure relief valve (one on the right—hand rail)

112490

81388

RAIL FOR G-DRIVE / DRAGON / SPRINKLER APPLICATIONS

RAIL FOR GRIFFON APPLICATION

SECTION 2 - FUEL

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Single—stage pressure relief valve (item 4, Figure 18)

Fitted at one end of the rail, its function is to protect the system’s components if any malfunctioning of the rail pressure sensor
or of the pump pressure regulator causes an excessive increase in the pressure of the high—pressure system.

The valve is a mechanical type and when the pressure in the high—pressure system reaches 1850 bar the valve opens to run fuel
off into the outlet line and accordingly reduce the pressure to acceptable values.

Flow limiters (item 2, Figure 18)
Located on the fuel outlet unions from the common rail, they protect the engine and vehicle in the event of larger fuel leakage
after the flow limiter (e.g. a jammed open nozzle) or external leakage (e.g. damage in high—pressure pipes).

Under this circumstance, cut off the fuel to the cylinder in question.

!

To reset the flow limiter it is necessary to stop the engine in order to zero the rail pressure.

However, if the cause of it switching on is not removed, the same fault will occur the next time the engine is started.

If the leakage is considerable, it will be impossible to restart the engine due to the lack of pressure in the rail.

Figure 19

Single—stage pressure relief valve (item 5, Figure 18)

Fitted at one end of the rail, its function is to protect the system’s components if any malfunctioning of the rail pressure sensor
or of the pump pressure regulator causes an excessive increase in the pressure of the high—pressure system.

The valve is a mechanical type and when the pressure in the high—pressure system reaches 1850 bar the valve opens to run fuel
off into the outlet line and accordingly reduce the pressure to acceptable values.

or lower for the single—stage
valves

22

SECTION 2 - FUEL

VECTOR 8 ENGINES

Base - April 2006

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Figure 20

The flow of fuel from the common rail to the injectors takes place via the ports in the small diameter of the piston.

In normal conditions, the pressure of the fuel is exerted on both sides of the piston, maintained by the spring in
the opening position

If there is a substantial loss in pressure downstream of the limiter, the inlet pressure becomes predominant and
moves the piston to the opposite side, obstructing the outlet of the fuel.

Limiter with piston in outlet closed position.

89672

1. Body - 2. Piston - 3. Fuel inlet - 4. Spring - 5. Part bolted onto the common rail

A

B

C

SECTION 2 - FUEL

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Figure 21

Electro—injector

The high—pressure pump keeps the delivery fuel pressure constantly high, irrespective of the phase and the cylinder that must
receive the injection and it accumulates the fuel in the common rail and piping to all the electro—injectors.

At the electro—injector inlet there is therefore always fuel available at the injection pressure calculated by the engine’s electronic
control unit (ADEM III).

When the solenoid valve of an electro—injector is energized by the electronic control unit, fuel taken directly from the rail is
injected into the relevant cylinder.

1. Nozzle — 2. Electro—injector — 3. Seals

103478

24

SECTION 2 - FUEL

VECTOR 8 ENGINES

Base - April 2006

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