AUC mode

In the recirculated-air control (AUC) mode, automatic switches are made between fresh air and recirculated air mode depending on the quality of the ambient air.

If the AUC sensor measures a rise in the pollutant emissions in the environment, the IHKA control module automatically activates the recirculated air mode. To ensure adequate fresh-air supply, the recirculated air mode has a time limit:

• at outside temperatures below 0 °C:

  2 min recirculated air mode -> 1 min fresh-air mode -> 2 min recirculated air mode - > etc.

• at outside temperatures of 0 °C to 6 °C:

  3 min recirculated air mode -> 1 min fresh-air mode -> 3 min recirculated air mode - > etc.

• during operation without air-conditioning function at outside temperatures above 6 °C:

  4 min recirculated air mode -> 1 min fresh-air mode -> 4 min recirculated air mode - > etc.

• during operation with air-conditioning function at outside temperatures above 6 °C:

12 min recirculated air mode -> 1 min fresh-air mode -> 12 min recirculated air mode - > etc.

When the AUC function is activated, during an engine start there is a switch for approx. 40 s to the fresh-air mode due to the warming phase of the AUC sensor.