Evaporator control (compressor control)
Evaporator control is activated by setting the rotary control to the recirculating air with air conditioning or outside air with air conditioning position .
The controlled compressor has a cut-out threshold between 1 °C and 3 °C . Mechanical control of the compressor output ensures the compressor clutch rarely cuts out.
The A/C compressor is activated directly by the heater/air conditioner unit . The auxiliary fan is controlled by the DME .
The pressure sensor monitors the refrigerant pressure and switches off the compressor at a pressure >32 bar . The compressor cuts in again at a pressure <24 bar . The compressor also cuts out at a vacuum <2 bar .
Air conditioning switch-on conditions :
Air conditioning switch-off conditions :
DME_KO Compressor control
The DME receives the instruction to switch on the compressor via the K-bus . If the conditions for full load cutout do not apply , the IHKS is enabled to switch on the A/C compressor . The load of the A/C compressor is determined from the pressure sensor signal and transferred to the DME via the K-bus .
DME_AC Idle speed increase
When the air conditioning is switched on, the IHKS requests an idle speed increase via the K-bus in order to be able to generate satisfactory cooling power also at idle speed.
Infinitely variable auxiliary fan control
The refrigerant pressure in the air conditioning system is recorded by the pressure sensor and the corresponding fan stage is allocated from a table. The fan stage is transferred via the K-bus to the DME . Consequently, the DME generates the control voltage for the infinitely variable auxiliary fan motor .