GF07.16-P-3004OHL | CDI quantity control, function | 5.5.08 |
ENGINE 642.9 in MODEL 221.0 as of Model Year 09 /Modification Year 08
ENGINE 642.9 in MODEL 221.1 as of Model Year 09 /Modification Year 08
General function requirements
Circuit 61 ON
Common rail diesel injection (CDI) quantity control - general
The CDI control unit (N3/9) regulates the injection quantity in all operating conditions. To do this, the CDI control unit reads in information from the following components:
- Oil temperature sensor (B1)
- Left hot film mass air flow sensor (B2/6)
- Right hot film mass air flow sensor (B2/7)
- Rail pressure sensor (B4/6/)
- Charge pressure sensor (B5/1)
- Camshaft Hall sensor (B6/1)
- Coolant temperature sensor (B11/4)
- Charge air temperature sensor (B17/8)
- Pressure sensor downstream of air filter (B28/5)
- Accelerator pedal sensor (B37)
- Crankshaft Hall sensor (B70)
Function sequence
Following evaluation of input signals, the CDI control unit regulates the injection quantity for each individual cylinder according to the injection sequence. To adapt the injection quantity, the CDI control unit lengthens or shortens the actuation time of the fuel injectors (Y76), taking account of the rail pressure, and raises or lowers the fuel pressure in the rail using the pressure regulator valve (Y74) and quantity control valve (Y94). The injection quantity is subdivided into preinjection quantities, the main injection quantity, and post injection quantities.