198002599 - INTRODUCTION - INJECTORS AND PIPES
DESCRIPTION OF COMPONENTS
INJECTORS
The injectors are fitted on the cylinder head and controlled by the injection control unit.The injector can be divided into two sections:
- actuator/spray consisting of pressure rod (1), pin (2) and nozzle (3);
- control solenoid consisting of coil (4) and pilot valve (5).
Classification into grades 1-2-3
During the test stage the injectors are checked with the specifications verified in different pressure/flow rate conditions. All injectors that do not meet a certain standard are rejected; the remaining ones are classified into three grades (1-2-3); this grade is imprinted by laser on the top part of the magnet.During fitting on the vehicle the control unit should memorise the individual grade and, if one or more injectors are replaced in a service situation the new injector grade should be included during the fault diagnosis using the appropriate equipment.1. Pressure rod2. Pin3. Nozzle4. Coil5. Pilot valve6. Ball plunger7. Control area8. Supply volume9. Control volume10. Fuel return - low pressure11. Control duct12. Feed duct13. Electrical connection14. Fuel return connector - high pressure15. Spring16. Injector grade
COMMON RAIL
The common rail is fitted to the intake side of the cylinder head.With a volume of around 33 cm³, this damps fuel pressure fluctuations due to:
- pressure pump operation
- injector opening.