Intake air temperature sensor DDE6.0

The intake air temperature sensor is integrated in the mass air flow sensor and measures the temperature of the fresh air drawn in by the engine.

The intake air temperature serves as a measurement variable in the DDE control unit for the following functions:

• Calculation of injection start and fuel injection period
  
• Release of pre-injection
  
• Power requirement calculation, engine
  
• Rail pressure control
  
• Charge-air-pressure control
  
• Exhaust gas recirculation
  
• Glowplug control
  

Function

The DDE control unit supplies the intake air temperature sensor with voltage and earth as follows:

• U_HR, battery voltage
  
• M_HFM, ground
  

The intake air temperature sensor returns the intake-air temperature via the signal T_TANS to the DDE control unit.

The signal is a square-wave signal with an amplitude of 5 V and frequency of around 19 Hz. This frequency corresponds to a period duration of 53 ms.

The DDE control unit uses the pulse duty factor of this signal to calculate the intake-air temperature in °C. The pulse duty factor can lie between 10 % and 90 %.

Troubleshooting

Faults in the component 'intake air temperature sensor' result in one or more fault reactions:

• Exhaust gas recirculation is deactivated
  
• Deactivation of turbo pressure control
  
• Volume limitation
  
• Output of a substitute value dependent on engine speed