INTRODUCTION - DIESEL PRESSURE PUMP AND CONTROL

1.9 Multijet

PRESSURE PUMP

Specifications

Type

The pump is radialjet type with three radial pistons (total cylinder capacity 0.697 cc) and is driven by a toothed belt without the need to adjust timing.

Structure

Because the pressure pump must be fed at a pressure of at least 3.5 bar, the fuel system is equipped with an auxiliary fuel pump submerged in the tank.

The maximum delivery pressure reaches 1600 bar.

The pressure pump is lubricated and cooled by the fuel via special channels.

The movement of the pistons is determined by the rotation of a triangular shaped cam on the pump shaft. This cam causes the movement of the three pistons in succession through the movement of a mechanical interface (tappet) between the cam and the foot of the piston. The contact between the cam and each individual tappet is ensured by means of a spring.

Each pumping unit is equipped with an intake valve and a supply ball valve. All the three supplies for the pumping elements are joined inside the pump and send the fuel to the shared manifold by means of a single duct.

There is a low pressure regulator solenoid valve on the pump to adjust the supply pressure at the pump intake in order to only compress the diesel fuel needed to reach the pressure mapped in the control unit

PRESSURE REGULATOR

Specifications

Structure

This is fitted on the pressure pump and controlled by the injection control unit. It adjusts fuel feed pressure to the injectors.

The pressure regulator consists mainly of the following components:

- a spherical shutter (1);

- a valve (3) controlling pin (2);

- a preloading spring (4);

- a coil (5).

1. Spherical plunger

2. Pin

3. Valve

4. Preload spring

5. Coil

6. Case

7. Anchor

1.3 Multijet

SPECIFICATIONS (For the 75 CV version)

Type

The CP1 pressure pump (1) is the radialjet type with three radial pistons (total capacity 0.567 cc) and is controlled by the camshaft by means of an oldham joint (2); there are no timing positions.

Structure

Each pumping unit consists of:

- a piston operated by a cam in one piece with the pump shaft;

- a plate-type intake valve;

- a ball delivery valve.

Because the pressure pump must be fed at a pressure of at least 0.7 bar, the fuel system is equipped with an auxiliary fuel pump submerged in the tank.

The maximum delivery pressure reaches 1400 bar.

The pressure pump is lubricated and cooled by the fuel via special channels.

SPECIFICATIONS (For the 90 CV version)

Type

The CP1 H pressure pump (1) is the radialjet type with three radial pistons (total capacity 0.697 cc) and is controlled by the camshaft by means of an oldham joint (2); there are no timing positions. There is a fuel pressure regulator (3) fitted on the pump connected to the injection control unit for modulating the flow rate.

The fuel pressure regulator is an integral part of the pressure pump and therefore no removing-refitting operations are permitted.

Structure

Each pumping unit consists of:

- a piston (1) operated by a cam (2) in one piece with the pump shaft (3);

- a plate-type intake valve (4);

- a ball delivery valve (5).

Because the pressure pump must be fed at a pressure of at least 0.7 bar, the fuel system is equipped with an auxiliary fuel pump submerged in the tank.

The maximum delivery pressure reaches 1600 bar.

The pressure pump is lubricated and cooled by the fuel via special channels.

PRESSURE REGULATOR

Specifications

This is fitted on the rail and controlled by the injection control unit. It adjusts fuel feed pressure to the injectors.

The pressure regulator consists mainly of the following components:

- a spherical shutter (1);

- a valve (3) controlling pin (2);

- a preloading spring (4);

- a coil (5).

1. Spherical plunger

2. Pin

3. Valve

4. Preload spring

5. Coil

6. Case

7. Anchor

8. Filter