Electrical swirl flaps DDE5.0/DDE6.3

The adjustable swirl flaps are located in the tangential channels of the intake system and are opened and closed according to the operating status of the engine. The swirl flaps are closed under the following conditions:

• at low engine speeds and low injection volumes (map-controlled)
  

The swirl flaps generally open when

• the coolant temperature < 14 °C OR
  
• the amount of fuel > 24 mg OR
  
• engine speed > 2250 rpm OR
  
• the intake temperature < -5 °C.
  

Function

In the case of the M57 TU with exhaust emission stage EURO 4 and the M67 TU, an electric motor activates the control rod to close the swirl flaps. The control rod is up against the rear stop when the swirl flaps are open.

The swirl flaps are sealed when closed in the tangential ducts with rubber gaskets.

Effects of faults

If the swirl flaps stick in open position: Deterioration in exhaust gas characteristics in lower speed ranges otherwise no effect.

If the swirl flaps stick in closed position: Loss in power output of approx. 10 % at higher engine speeds, danger of engine overheating.