Airflow Control

Depending on the Energy Requirement Level (ERL) condition signal, the airflow is adjusted under program control by regulating the voltage supplied to the fresh-air blower. Appropriate characteristics exist for both automatic mode and manually selected air distribution.






Diagram for blower voltage in automatic mode

The following functions also effect the blower voltage:
Cold-start reduction
With a cold-start, there is a 20-percent reduction in voltage for the fresh-air blower. This prevents an unpleasant discharge of cold air.

Ambient temperature correction
At ambient temperatures below - 10 °C, the airflow for the air-conditioning device is increased to support heating output.

Solar radiation correction
A radiation-dependent increase in the blower voltage is used to counter a temperature rise in the passenger compartment resulting from solar radiation.

Air-recirculating reduction
In manual air-recirculating mode, the fan voltage for the appropriate fresh-air characteristic is reduced to 85 percent in order to achieve noise and airflow compensation.