GF83.10-P-2000GM Ventilation System, Function
GF83.10-P-2000GM Ventilation System, Function
Air outlets in passenger compartment
Air outlets in passenger compartment
General function requirements
^ Circuit 15 On
The circuit status of circuit 15 is provided by the EIS [EZS] control unit (N73) on the interior CAN (CAN-B).
Ventilation, general
The ventilation system prevents windows from fogging up, supplies air to the vehicle occupants, and ensures that uniform and pleasant temperatures in the vehicle interior are reached quickly. When the fresh air/air recirculation flap is adjusted correspondingly, fresh air is supplied to the air conditioner housing via the air inlet. Depending on the current settings on the AAC [KLA] control and operating unit (N22) (without code (581) Comfort automatic air conditioning) or on the comfort AAC [KLA] control and operating unit (N22/7) (with code (581) Comfort automatic air conditioning), the air is directed through air ducts and air outlets into the vehicle interior.
In order to prevent window fogging, the defroster vent flaps and the fresh air/air recirculation flap are closed and the footwell flaps fully opened after t = 2 min after switching off circuit 15. After starting the engine, the defroster vent flaps and the footwell flaps remain in this fixed position for t = 30 s. The fresh air/air recirculation flap can be adjusted immediately. After that, all adjustments are possible again.
The ventilation system comprises the following subfunctions:
^ AC component actuation function sequence
^ Fresh air mode function sequence
^ Air recirculation mode function sequence
AC component actuation function sequence
The AC component actuation function sequence comprises the following subfunctions:
^ Function sequence, actuation of blower motor (A32m1)
^ Function sequence, actuation of the air ducting flaps
Function sequence, actuation of blower motor
Ventilation is achieved with the aid of the blower motor. The control and operating unit transmits an actuation of 0 to 100 % over the climate control LIN (LIN B8) to the blower regulator (A32n1). Depending on the control voltage, the blower regulator regulates the operating voltage for the blower motor from U = 0 V up to U = 12 V and thus the rotational speed of the blower motor from 0 up to 100 %.
The actuation (operating voltage) of the blower motor is influenced by the following factors:
- Blower selector wheel setting ("MANUAL"/"AUTO")
- "AC OFF" (On/Off)
- Mode (heating/cooling)
- Coolant temperature
- Vehicle speed
- Solar radiation
- Fresh air/air recirculation flap position
- Ambient temperature
- Flap positions
- Circuit 15 On (blower ON), circuit 50 On (starter running, blower off)
- Window position, tilting/sliding roof position (with code (414) Electric glass tilting/sliding roof) or panoramic roof position (model 251 with code (413) Panoramic glass sunroof with top sliding sunroof)
- Vent window position (model 164.8 and model 251 with code (848) Electric side vent window)
- Air humidity (dew point) (with code (581) Comfort automatic air conditioning)
- Pollutant concentration (with code (581) Comfort automatic air conditioning)
- Residual engine heat utilization function, stationary ventilation function
- Variant coding
The blower output can be increased to match the outside temperature. To keep the inside temperature constant and the windows clear at low temperatures, the blower output is increased by 15 % at outside temperatures of T = -10 �C to -15 �C.
With code (581) Comfort automatic air conditioning without code (582) Rear air conditioning, the ventilation of the rear compartment is supported by the booster blower motor (M2/1). The actuation is carried out by the control and operating unit directly at the booster blower electronic blower regulator (N29/2). This directly actuates the booster blower motor.
With code (582) Rear air conditioner, ventilation of the rear compartment is assisted by the rear air conditioning system blower motor (M2/29). Actuation is carried out directly by the control and operating unit via the climate control LIN at the rear air conditioning system blower regulator (N29/7). This then actuates the rear air conditioning system blower motor directly.
As of 1.7.09, the blower output is limited with an active voice control system.For this purpose the radio and navigation unit A2/56) (with code (511) Audio 50 APS with DVD changer) or the COMAND operating, display and controller unit (A40/3) (with code 512) COMAND APS with DVD changer or with code (527) COMAND APS with single DVD drive (with navigation)) transmits the status of the voice control system to the control and operating unit via the interior CAN. This then limits the blower output.
Air ducting flaps actuation function sequence
The control and operating unit actuates the following components for adjustment of the air ducting flaps via climate control LIN:
Vehicles without code (581) Comfort automatic air conditioning:
- for fresh air/air recirculation control:
- Fresh air/air recirculation flap actuator motor (M2/5)
- for temperature control:
- Left blend air flap actuator motor (M2/6)
- Right blend air flap actuator motor (M2/7)
- for ventilation control:
- Rear shutoff flap actuator motor (M2/12)
- Left and right footwell flaps actuator motor (M2/15)
- Left and right defroster flaps actuator motor (M2/16)
- Rear air distribution flap actuator motor (M2/21)
- Center vent flap actuator motor (M2/22)
Vehicles with code (581) Comfort automatic air conditioning:
- for fresh air/air recirculation control:
- Fresh air/air recirculation flap actuator motor
- for temperature control:
- Left blend air flap actuator motor
- Right blend air flap actuator motor
- for ventilation control:
- Left defroster flap actuator motor (M2/8)
- Right defroster flap actuator motor (M2/9)
- Left footwell flap actuator motor (M2/10)
- Right footwell flap actuator motor (M2/11)
- Rear shutoff flap actuator motor
- Center vent flap actuator motor
- Left center air flap actuator motor (M16/23)
- Right center air flap actuator motor (M16/24)
Fresh air mode function sequence
The fresh air/air recirculation flap is open and fresh air is delivered into the vehicle interior through the heater or air conditioning box.
Air recirculation mode function sequence
The air recirculation mode function sequence comprises the following subfunctions:
^ Air recirculation mode function sequence via air recirculation switch (N22s2) (without code (581) Comfort automatic air conditioning) or air recirculation switch (N22/7s2) (with code (581) Comfort automatic air conditioning)
^ Pollutant-controlled air recirculation mode function sequence
(with code (581) Comfort automatic air conditioning)
Air recirculation mode function sequence via air recirculation switch
When the air recirculation switch on the control and operating unit is pressed for t < 1.5 s, the fresh air/air recirculation flap is closed, and thus the supply of outside air is prevented. The air only circulates in the vehicle interior and unpleasant odors and harmful gases are kept out. The LED in the air recirculation switch comes on.
Pressing the air recirculation switch for t > 1.5 s activates comfort recirculation closing. In the process the windows, the tilting/sliding roof (with code (414) Power glass tilting/sliding roof) or the panoramic sunroof (model 251 with code (413) Panoramic glass sunroof with top sliding sunroof) and the vent windows (model 164.8 and model 251 with code (848) Power side vent windows) are closed automatically. If the air recirculation switch is activated again for t > 1.5 s, the previous positions are returned to.
With code (460) Canada version and code (494) USA version, convenience recirculation closing is not possible.
The detailed convenience recirculation closing procedure is described in the convenience feature function (KFB).
Additional function requirements for pollutant-controlled air recirculation mode
^ Refrigerant compressor (A9) switched on
^ Defrost mode not active
Pollutant-controlled air recirculation mode function sequence
The pollutant sensor (B31) directly transmits the pollutant values of the outside air to the control and operating unit. Starting from a certain pollutant concentration, the fresh air/air recirculation flap is automatically set to the recirculated air position. Outside air supply is prevented and only the inside air is recirculated.
The LED in the air recirculation switch comes on accordingly.
