Operation

OPERATION

The injector works in three steps:

• "rest position"

The coil (4) is de-energised and the shutter (6) is in the closed position and does not allow the delivery of fuel into the cylinder Fc > Fa (Fc: due to the line pressure which acts directly on the control area 7 of the rod 1; Fa: due to the line pressure which acts in the supply volume 8).

• "start of injection"

The coil (4) is energised and causes the shutter (6) to rise.

The fuel of the control volume (9) flows towards the return manifold (10) causing a pressure drop on the control area (7).

Simultaneously, the line pressure through the supply duct (12) exerts a force Fa > Fc in the supply volume (8) causing the pin (2) to rise, thereby sending fuel into the cylinders.

• "end of injection"

The coil (4) is de-energised and makes the shutter (6) return to the closed position which again creates a balance of force which returns the pin (2) to the closed position, resulting in the end of injection.

1. Pressure rod
2. Pin
3. Nozzle
4. Coil
5. Drive valve
6. Ball shutter
7. Control area
8. Supply volume
9. Control volume
10. Fuel return - low pressure
11. Control duct
12. Supply duct
13. Electrical connection
14. Fuel inlet - high pressure coupling
15. Spring

REMOVAL/REFITTING

• Make sure that the ignition key is at "STOP", then disconnect the battery terminal (-).

1. Remove the engine oil filler cap.
2. Slacken the fastening screws and remove the engine cover.
3. Refit the engine oil filler cap.