Smooth running control

The smooth running control facility balances out the speed fluctuations of the individual cylinders caused by different fuel injection rates and degrees of cylinder efficiency. This is achieved by rapid application of controlled corrected fuel injection rates at each cylinder for each injection.

The maximum compensation output by the DDE depends on the fuel injection rate and is between ± 3 and ± 6 mm/stroke.

The control is active within a certain engine speed and fuel injection rate range:

• Engine speed range: target idle speed up to 3500 rpm
  
• Fuel injection rate range, speed-dependent:
  idle speed up to 2000 rpm: fuel injection rate < 60 mg/stroke
  Above 2500 rpm: fuel injection rate < 45 mg/stroke
  2000 rpm to 2500 rpm: interpolated between 60 mg/stroke and 45 mg/stroke
  

Monitoring

If the compensation figure for a particular cylinder exceeds a specific limit, there are two faults that can be stored:

• 4B10, Smooth running control, compensation too great
  
• 4B11, Smooth running control, compensation too small
  

The limit value is dependent on the fuel injection rate and is between ± 4.9 and ± 5.9 mm/stroke.