Automatic Air-Recirculation Control

If the AUC II sensor detects an increased level of pollutants in the environment from spark-ignition and diesel engines, the IHKA control unit will automatically switch to air recirculation mode.

To make sure there is still an adequate supply of fresh air, air recirculation is only available for a limited time:

• At ambient temperatures less than 0°C:

  2 minute recirculated air mode -> 20 seconds fresh air mode -> 2 minute recirculated air mode -> etc.

• At ambient temperatures from 0°C to 6°C:

  3 minute recirculated air mode -> 20 seconds fresh air mode -> 3 minute recirculated air mode -> etc.

• Operation without a/c function at ambient temperatures greater than 6°C:

  4 minute recirculated air mode -> 20 seconds fresh air mode -> 4 minute recirculated air mode -> etc.

• Operation with a/c function at ambient temperatures greater than 6°C:

  12 minute recirculated air mode -> 20 seconds fresh air mode -> 12 minute recirculated air mode -> etc.

When the engine is started and the AUC function activated, fresh-air mode is always selected for approx. 40 seconds due to the warming phase of the AUC sensor.