GF07.16-P-3009OHL | CDI zero quantity calibration, 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
Sliding operation
Engine speed between 2000 rpm - 2500 rpm
Engine temperature > 50 °C
Fuel temperature 30 °C to 50 °C
O2 sensor upstream of CAT (G3/2) and crankshaft Hall sensor (B70) must be adapted
Battery voltage > 11 V
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Common rail diesel injection (CDI) zero quantity calibration - general
Due to the change in friction (wear) when the fuel injectors (Y76) open and close, actuation time may become longer or shorter over the life-span of the injectors. Zero quantity calibration is used to compensate for this change.
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Function sequence
Zero quantity calibration is carried out at different specific injection pressures in deceleration mode. In this mode, the fuel injectors are actuated one after the other with calibration value and the corresponding engine speed is evaluated. If the corresponding engine speed differs from the stored specified value, the calibration value is adapted and stored in the control unit.
The CDI control unit analyzes information from the following sensors to do this:
- Oil temperature sensor (B1)
- Rail pressure sensor (B4/6/)
- Charge pressure sensor (B5/1)
- Coolant temperature sensor (B11/4)
- Charge air temperature sensor (B17/8)
- Accelerator pedal sensor (B37)
- Fuel temperature sensor (B50)
- Crankshaft Hall sensor
- O2 sensor upstream of CAT