Engine speed detection DDE

Two sensors are used to detect the engine speed and the position of the camshaft and the crankshaft:

• Crankshaft position/rpm sensor
  The DDE control unit uses the crankshaft signal to calculate the precise engine speed and detect the TDC positions for each cylinder.
  
• Camshaft Hall-effect sensor
  The DDE control unit uses the camshaft signal to determine whether a cylinder is at TDC on the compression or exhaust stroke. Only if those signals are correctly detected can the DDE control unit activate the correct injector at the correct time.
  

For starting the engine, the DDE control unit checks the following conditions:

• the two signals must not have any faults
  
• the signals must be detected in a specific chronological sequence
  

This process is referred to as synchronisation and is only performed when the engine is started. The DDE control unit cannot activate the correct injector at the correct time unless synchronisation has been completed.

Engine start is not possible without synchronization!