Air distribution IHKA RR

The air distribution takes place automatically. In principle, the inside of the vehicle can be ventilated by means of the following air vents:

• Air vents for defrosting the windscreen
  
• Eyeball vents, outer front left and centre
  
• Eyeball vents, outer front right and centre
  
• Knee vents, front left and right
  
• Footwell vents, front left and right
  
• Eyeball vent, rear middle left
  
• Eyeball vent, rear middle right
  
• Footwell vents, rear left and right
  

Influences on the air distribution

The automatic air distribution is influenced by the following factors:

Position of the actuating sliders on the eyeball vents

The potentiometers for adjustment of the air flaps behind the eyeball vents are connected via deflection levers with the actuating sliders. The following relationship exists between the position of the actuating slider, the signal voltage at the potentiometer and finally the flap position:

• Actuating slider pulled as far as it will go:
  
  • Signal voltage 3.3 ... 3.5 V
    
  • Flap is fully opened
    
• Actuating slider pushed as far as it will go:
  
  • Signal voltage 1.4 ... 1.8 V
    
  • Flap is fully closed
    
• Actuating slider in the intermediate area:
  
  • 1.8 V < signal voltage < 3.3 V
    
  • Flap position linear to the voltage
    
• Exception: If the air flap of a knee vent is opened, the air flap at the front centre eyeball vent on the corresponding side is choked in the heating mode to 50 %; in the cooling mode it is closed. In the transition between the heating and cooling mode, linear characteristics as regards the adjusting value set in.
  
• Influence on the position of the air flaps of the indirect air vents
  The air flap at the indirect air vents react as follows to the position of the actuating slider for the air vents positioned in the centre of the dashboard:
  
  • Actuating slider pulled as far as it will go:
    
    • indirect air vents closed
      
  • Actuating slider pushed as far as it will go:
    
    • indirect air vents opened
      
  • Actuating slider (and thus the potentiometer setting) to 50 %:
    
    • direct and indirect air vents opened 100 %
      
  • Actuating slider in intermediate area:
    
    • direct and indirect air flap have opposing linear characteristics
      

Position of the slide switch for the knee vents

When the slide switch is pushed in, the Hall signal is active and the air flap of the knee vent is closed. If the slide switch is pulled out, the Hall signal is inactive and the air flap is opened.

Setting the stage for the automatic defrost

OFF position: in the OFF position, the linked defrost flaps are closed.

LOW, MED and HIGH positions: in the LOW, MED and HIGH positions, the linked defrost flaps are positioned in line with characteristic curves stored in the control unit.

Exception: To prevent fogging during a start, the connected defrost flaps remain closed for 12 seconds after an engine start.

The blower output is raised by a corresponding value so as not to influence the air volume distribution at the eyeball and knee vents and to provide the driver with acoustic feedback. This fixed blower speed increase is stored in the control unit for each of the three positions.

DEF position: in the DEF position, the linked defrost flaps are opened 100 %. The power output of the main blower is raised by a fixed value stored in the control unit.