Air distribution IHKA

Air distribution IHKA

This functional description covers the air distribution of the IHKA. The IHKA is a heating and air conditioning system regulated on the on air side. The interior temperature is picked up by two independent temperature sensors. The sunlight level is picked up by the solar sensor.

Brief description of components

Buttons for air distribution

Air distribution flap mechanical system and air distribution flap motor

Air distribution is carried out by the air distribution flap, which in turn is adjusted by the air distribution flap mechanical system. The mechanical system is driven by the air distribution flap motor.

The air distribution flap motor has no detection of its current position. For this reason, the flap motor must be activated depending on a reference position. This enables exact and reproducable positioning.

System functions

Reference run of the air distribution flap motor

The reference position is an end position of the air distribution flap. Evaluation of the flap motor load current indicates the end position.

The reference run is carried with every ”power on reset”. It can also be triggered by the BMW diagnosis system.

Programs for air distribution

Air distribution can manual or automatic. With automatic air distribution, the air is distributed in the vehicle interior depending on sensors. Manual programs cover operating modes that cannot be detected automatically by the IHKA (e.g. window condensation on the windscreen).

The priority of the manual programs is higher than that of the automatic program.

Manual program selection

With active manual air distribution, the influence of the sunlight is not compensated. The air distribution can be set individually. Combinations of the individual air distribution buttons are possible (see table below). The selected settings are displayed in the IHKA display.

• Air distribution, top
  Pressing the top air distribution button guides the air-mass flow to the air vents for defrosting.
  
• Air distribution, centre
  Pressing the centre air distribution button guides the air-mass flow to the ventilation air vents.
  
• Air distribution, bottom
  Pressing the bottom air distribution button guides the air-mass flow to the footwell air outlets
  
• Defrost function
  Pressing the button for defrost guides the air-mass flow to the air vents for defrosting. The blower output is set by the IHKA control unit to the maximum level. For the defrost function, the maximum blower output is always available, as this function is relevant to safety. The heated windscreen (if fitted) is switched on. The blower output can be lowered manually.
  

Automatic program

The automatic function of the IHKA is activated by pressing the AUTO button. The air-mass flow is regulated by the IHKA control unit. The blower output continues to be automatically adapted.
The air distribution is regulated depending on the desired temperature value, the temperature sensors and the sunlight sensor. This enables an optimised climate in the vehicle interior.

Notes for Service department

Observe the following information for service:

Coding and programming

• Coding
  When coding the vehicle-specific data, the following details (among others) are taken into account:
  
  • Engine variant (diesel engine or petrol engine)
    
  • Version of the control unit (IHKA)
    
• Programming
  Flash programming of the IHKA control unit via the K-CAN is possible.
  

Country-specific versions

The temperature display can be switched to °C or °F using the on-board computer function.

No liability can be accepted for printing or other errors. Subject to changes of a technical nature