Air Circulation

Functions
With ambient temperatures > 26 °C, the air-recirculating mode is automatically selected by the program after a ventilation time of 30 seconds in order to accelerate the cooling phase.

Temperature-mix flap
Cooling mode occurs below the condition variable ERL < 85.
The reference variable for the mix-flap position is directly dependent on the results from calculations to determine the flap position.

Heating mode occurs above ERL > 150.

In this case, a secondary footwell discharge controller alone determines the position of the mix flap.

At ERL > 85, control of the mix flap is taken over by the active footwell discharge regulator.





Diagram showing mix-flap position (without footwell discharge regulator)

Footwell discharge regulation
The system allows discharge regulation secondary to the passenger compartment temperature control loop to be performed. This is possible whenever air flows around the temperature sensor located behind the foot- well defrost flap in the footwell nozzle.

If the flow of air is not detected, e.g. in manual middle nozzle mode, the temperature-mix flap is permanently coupled to the Energy Requirement Level (ERL) according to the mix-flap control characteristic. The same procedure is applied in the case of a faulty sensor.