Iveco Daily. Manual

85847

Figure 250

1 Delivery valve on single pumping element — 2. Relief valve 5 bar — 3. Pressure regulator — 4. Fuel inlet from filter — 5. Pump

shaft — 6. Delivery valve to common rail — 7. Fuel return from high-pressure pump — 8. Mechanical supply pump.

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70498

Figure 251

Each pumping assembly comprises:

- a plunger (5) operated by a three-lobed element (2)

floating on the shaft of the pump (6). Since the element
(2) floats on a misaligned portion of the shaft (6), during
shaft rotation, it does not turn with it but is only shifted

1. Cylinder — 2. Three-lobed element — 3. Plate intake valve — 4. Ball delivery valve — 5. Plunger — 6. Pump shaft —

7. Low-pressure fuel inlet — 8. Fuel ducts to supply pumping elements.

in a circular movement on a wider radius, with the result
of working the three pumping elements alternately:

- a plate intake valve (3);

- a ball delivery valve (4).

Sec. B-B

Sec. C-C

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Figure 252

The pumping element (3) is arranged on the cam on the pump
shaft. In the suction phase, the pumping element is supplied
through the supply duct (5). The amount of fuel to send to the
pumping element is determined by the pressure regulator (7).
The pressure regulator, on the basis of the PWM command

1. Outlet for delivery to rail — 2. Delivery valve to rail — 3. Pumping element — 4. Pump shaft — 5. Pumping element supply

duct — 6. Pressure regulator supply duct — 7. Pressure regulator.

Working principle

Figure 253

received from the control unit, chokes the flow of fuel to the
pumping element. During the compression phase of the
pumping element, the fuel, on reaching such a pressure as to
open the delivery valve to the common rail (2), supplies it
through the outlet (1).

Sec. D - D

Sec. B - B

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Figure 254

Figure 254 shows the low-pressure fuel routing in the pump;
it highlights the main supply duct of the pumping elements (4),
the supply ducts of the pumping elements (1-3-6), the ducts
used to lubricate the pump (2), the pressure regulator (5), the
5-bar relief valve (8) and the fuel outlet.

The pump shaft is lubricated by the fuel through the delivery
and return ducts (2).

1, 3, 6 Pumping element inlet — 2. Pump lubrication ducts — 4. Main pumping element supply duct — 5. Pressure regulator —

7. Regulator outlet duct — 8. Relief valve 5 bar — 9. Fuel outlet from regulator inlet.

Sec. C — C (Figure 253)

The pressure regulator (5) determines the amount of fuel with
which to supply the pumping elements; excess fuel flows out
through the duct (9).

The 5-bar relief valve, besides acting as a manifold for the fuel
outlets, has the function of keeping the pressure constant at
5 bars at the regulator inlet.

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Content .. 105 106 107 108 ..

Iveco Daily. Manual - part 107