Charge-air pressure controller DDE6.3

Two variable nozzle turbine chargers without a ”wastegate” are used for charge-air pressure control.

Control levers on the turbine housings activate the adjustable guide vanes in the turbines. The control levers are operated by electrical controllers (electric motors with worm gear and electronic control) that are mounted directly on the turbochargers. The controllers cannot be replaced separately.

Charge-air pressure controller 1 is located in the direction of travel on the right.

Components

• Turbochargers with variable nozzle turbines and electric controllers
  

Function

The DDE master control module activates charge-air pressure controller 1; the DDE slave control activates charge-air pressure controller 2. The charge-air pressure controllers are activated with square-wave signals with pulse duty factors (= changeable pulse widths) between 5% and 95%.

Checking variable turbine geometry

The control levers must move between minimum and maximum activation by 35° to 45° angle of rotation. Adjustment must take place rapidly.

Troubleshooting

The charge-air-pressure control is monitored for the following faults:

• Positive and negative control deviation
  
• Faults in activation of the charge-air pressure controllers
  
• Defects in the charge-air pressure controllers, e.g. blocked or electrically defective
  
• Charge air hoses disconnected
  

Consequences of fault occurring in the charge-air pressure control system:

• Charge-air pressure control is deactivated, the charge-air pressure controllers operate with fixed pulse duty factors.
  
• Exhaust gas recirculation is deactivated
  
• In the event of a control deviation in the charge-air pressure, the injection volume is limited and a substitute value is output for the charge-air pressure.
  

Charge-air pressure control is also deactivated when following faults occur:

• Fault in the exhaust-gas recirculation
  
• Fault on the charge-air pressure sensor
  
• Fault on the crankshaft speed sensor
  
• Fault on the pedal-position sensors
  
• Fault on the air-mass sensors
  
• Fault at terminal 15
  
• Fault on the flow regulating valve
  
• Fault on the equalization controller