64 01 03 (006)
Integrated automatic heating / air-conditioning system (IHKA), Basic and High
The integrated automatic heating/air conditioning system (IHKA) is available in the versions Basic and High (option 534).
E60 and E61
Standard equipment: IHKA Basic (IHKA High on 545i)
E63 and E64
Standard equipment: IHKA High
The High automatic air conditioning system has separate settings for the driver's side and passenger's side.[System overview ...]
New features of the IHKA:
An electric auxiliary heater working on the PTC principle (positive temperature coefficient) is installed on vehicles with diesel engines
The electric auxiliary heater is a component of the heat exchanger for the heating system. Electric heating elements made of aluminium have been added to the fins in the coolant flow of the heating system heat exchanger. The air drawn in is directly heated by these heating elements and fed into the vehicle interior through the air vents. In principle, the electric auxiliary heater works like an electric fan heater.
The condensation sensor detects an imminent misting up of the windscreen, before condensation actually forms. To prevent the windows from misting over, the IHKA control unit starts to work through a table of measures as soon as a certain level of humidity is detected at the windscreen.
LIN bus (Local Interconnect Network bus)
The LIN bus serves to actuate flap motors, the electric auxiliary heater and the blower motor in the heating/air-conditioning system.
Convertible program (only E64)
When the soft top is opened and the air-conditioning system is in automatic mode, the convertible program is automatically activated.
The convertible program adapts the air-conditioner settings (blower, airflow, temperature) to the conditions created by the open soft top. The settings do not have to be changed when the soft top is opened or closed.
The convertible program is stored in the IHKA control unit.
Differences between IHKA Basic and IHKA High:
|Automatic air recirculation control sensor||---||1|
|Heating heat exchanger sensor||1||2|
|Ventilation temperature sensor||---||1|
|Rear compartment flap motor (air stratification)||---||1|
|Ventilation flap motor||1||2|
|Footwell flap motor||1||2|
Differences/modifications from E39:
- New IHKA control panel with additional functions: OFF button, temperature and airflow are set with rotary switches. On the IHKA Basic, the manual air distribution is set with the IHKA control panel. On the IHKA High, the manual air distribution is set with the controller on the CID (Central Information Display).
- Revised display conceptThe scale on the rotary switch for the blower setting has a 9‐element LED display. The manually blower speed setting is shown by the corresponding LEDs lighting up. In the automatic program, the display remains OFF (only IHKA High).The previous liquid crystal display is discontinued. Additional air-conditioning functions such as air stratification or independent heater (option 536) are selected and activated in the Central Information Display (CID) using the controller.
- The flap drives are only operated by flap motors.
- Separate left/right-hand footwell flaps, (IHKA High only)
- Separate ventilation flaps, (IHKA High only)
- Intake fan arrangement in the heating/air-conditioning systemThe fan is located after the evaporator.
- On vehicles with diesel engine, a heating system heat exchanger is installed with integrated electric auxiliary heater. The same heating system heat exchanger is used for both Basic and High versions.
- Clutchless, externally actuated a/c compressor with regulated performance
- Sensor for automatic air-recirculation control (AUC sensor, IHKA High only)
- Solar sensor for taking external light/heat sources into account, which could affect the air conditioning in the vehicle interior (IHKA High only).
Benefits of system:
- The efficiency and functionality of the IHKA has been improved compared to the predecessor model. Despite this, the size is some 1/3 smaller than on the E39.
- The electric auxiliary heater accelerates the heating of the vehicle interior, especially at low ambient temperatures and during the cold-start phase. This clears the windows of condensation more quickly.
- The condensation sensor automatically prevents/eliminates condensation on the inside of the windscreen, before it becomes visible.
- The variable evaporator control extracts less humidity from the air. This reduces the risk of mucous membranes drying out.
- Interior temperature sensor The forced-ventilated sensor with interior temperature sensor fan is fitted in the IHKA control panel. The sensor measures the temperature of the air drawn in from the vehicle interior by the integrated interior temperature sensor blower.
Solar sensor (IHKA High only)
The solar sensor is located in the middle of the dashboard. (The installation position of the solar sensor in the E63/E64 has been turned through 180°.) This sensor is only active in automatic mode. The solar sensor takes account of the presence of external light or heat sources (e.g. direct sunlight), which could affect the climate in the vehicle interior.The sensor comprises 2 photoresistors. The sensor supplies the IHKA control unit with analogue signals for the driver's and the passenger's sides. The signal depends on the intensity of sunlight.
Sensor for automatic air-recirculation control (IHKA High only)The AUC sensor is installed at the top of the fan cowl. The sensor is exposed to the sideways downwind from the auxiliary fan. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:
- Hydrocarbons (HC)
- carbon monoxide (CO)
- Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)
Condensation sensor (IHKA High only) The sensor is located under the rain/light sensor. In IHKA automatic mode, the sensor measures the humidity in the vehicle interior and on the inside of the windscreen. The sensor detects an imminent misting up of the windscreen, before condensation actually forms. The condensation sensor is not active in the convertible program.
- Heating system heat exchanger sensorThe sensor is integrated in the heating/air-conditioning system. On the IHKA Basic, the sensor measures the delivery temperature on the drivers side, directly on the delivery side of the heating system heat exchanger. On the IHKA High, 2 sensors are installed as the blow-out temperatures are measured separately at the heating system heat exchanger for the driver's and the passenger's side.
- Evaporator temperature sensorThe sensor measures the outlet temperature of the refrigerant at the evaporator to prevent icing from occurring.
- Ventilation temperature sensor (only integrated automatic heating and air-conditioning system in High version)For determining the ventilation temperature, a sensor is integrated in the air duct. This sensor measures the delivery temperature directly in the middle of the ventilation grille.
- Refrigerant pressure sensorThis sensor is located in the pressure line between the condenser and the evaporator. Depending on the sensor signal, the A/C compressor is switched off by the IHKA control unit in the event of excessively high system pressure.
IHKA control panel/control unit
The IHKA control panel and the IHKA control unit are combined in a single component. For the equipment specifications known as Basic and High, there are different IHKA control panels.[more ...]
Electric auxiliary heater
\The heating elements of the electric auxiliary heater are integrated into the heating system heat exchanger and directly heat the air drawn in to control the temperature of the air inside the vehicle.[more ...]
On the IHKA Basic, 6 flap motors control the ventilation flaps. The IHKA High has 9 flap motors due to the left/right separation for the driver's and the passenger's side and because of the additional rear compartment flap.[more ...]
Blower with blower output stage
The blower creates the necessary air mass flow. The blower is installed after the evaporator in the heating/air-conditioning system (suction fan) and is equipped with 2 blower wheels. The blower output stage is fitted directly on the blower motor housing. The blower output stage is capable of self-diagnosis. The blower output stage is actuated by the IHKA control unit (via the LIN bus). The blower output stage controls the blower motor with a pulse-width modulated signal (PWM signal).
Air conditioning compressor
The A/C compressor compresses the refrigerant drawn in from the evaporator and presses it to the condenser. The A/C compressor used is clutch-free. That means that the A/C compressor always runs with the engine. A swash plate in the A/C compressor allows the output to be smoothly regulated. For the purpose of load reduction, only the refrigerating output that is directly needed is generated.[more ...]
Measures to reduce CO2 emissions: Depending on the engine version and national-market version, an A/C compressor with magnetic coupling supersedes the A/C compressor previously installed with electric control valve.
The evaporator fins are cooled by the refrigerant that has been evaporated inside the evaporator. The air mass flow generated by the blower is fed over the cooled evaporator fins. The air is cooled and dried and fed into the vehicle.
Auxiliary water pump
The additional coolant pump serves to make sure that the coolant flow rate needed in the heater circuit is maintained, even at low engine speeds. On vehicles with diesel engine and independent heating (option 536), there is no additional coolant pump in the engine compartment. Its job is assumed by the independent heater's additional coolant pump and is controlled by the independent heating control unit.
The water valve operates electromagnetically and meters the coolant flow rate to the heating system heat exchanger as it is needed. This determines the temperature of the air used for heating the vehicle interior. On the IHKA High, a dual water valve is used for the left/right separation of the heating system heat exchanger.
The switchover valve is only installed if the vehicle is equipped with independent heating (option 536). The switchover valve regulates the inlet to the independent heating as follows:
- From the radiator and the additional coolant pump
- From the reverse flow from the heating system heat exchanger
The switchover valve is actuated by the independent heating control unit.
The auxiliary fan is standard on all vehicles with IHKA. The auxiliary fan and the engine cooling are also required for cooling the condenser.[more ...]
Capacitor with integrated dryer flask
Refrigerant is converted from gas into liquid in the condenser. In the integrated dryer flask, which is installed downstream of the condenser, any water that may be present in the refrigerant circuit is collected. The desiccant insert can be exchanged.
The expansion valve is directly on the evaporator in the heating/air-conditioning system. The valve regulates the injection rate in the evaporator. Only as much liquid refrigerant is permitted to enter the evaporator as the evaporator is able to completely evaporate. Drops of liquid that have not been evaporated could cause damage in the A/C compressor.
On the IHKA Basic, fresh air for interior ventilation is fed through a system of microfilters. On the IHKA High, a microfilter with activated carbon is fitted. The activated-charcoal filter helps to provide additional purification of the incoming fresh air from gaseous pollutant emissions. When a filter replacement is needed, this will be indicated by the Condition Based Service (CBS) display.
Rear air-stratification flap (IHKA High only)
The selected potentiometer setting is transposed into the rear compartment flap motor position.
local interconnect network bus
The IHKA control unit controls the following components via the LIN bus:
- Electric auxiliary heater
- Flap motors
- Blower with blower output stage
Control and display functions via controller and Central Information Display
The following control and display functions are selected and activated on the CID (Central Information Display) with the controller (move controller to left in start menu):
Temperature control (IHKA Basic)
The temperature for the driver's and the passenger's sides are centrally set on the IHKA control panel. The temperature can be increased or decreased from this central setting using 3 selectable settings (warmer, neutral, colder).
Temperature control (IHKA High)
The temperature can be increased or decreased separately on the driver's and the passenger's side in 4 increments.
Independent heater (optional)
Select between direct operation and programming with timer.
Independent ventilation (IHKA High only)
Select between direct operation and programming with timer.
Air distribution (IHKA High only)
The airflow for the driver's and the passenger's sides are centrally set on the IHKA control panel. Deviating from these central setting, the airflow can be adjusted separately for the footwell and upper body (driver's and passenger's sides). The driver-side setting applies for both sides in the area of the windscreen.
When the convertible program is active, air distribution is switched to the upper body and head. Airflow to the footwell is throttled.
The A/C program is called up as follows:
1. Press the controller in the start menu (5. menu) 2. Select ”Vehicle settings” and press controller. 3. Select ”A/C settings” and press controller. 4.
The following settings are available in the menu level ”automatic program”:
‐ convertible program (selection only possible when convertible top is open)
The selection of low, medium and high is not possible when the convertible program is active. When the convertible program is deactivated, the air-conditioning system acts as if the convertible top were closed (selection of low, medium and high is again possible).
The following control unit is also active in the IHKA:
Convertible top module (E64 only)
The convertible top module (CVM) provides the IHKA control unit with the signal whether the convertible top is open or closed. The soft top Module is connected on the K‐CAN.The convertible top module is installed under the rear, left-hand side trim panel.
- Temperature control
- Evaporator control
- Air distribution
- Air flow control
- Sunlight adaptation (solar sensor, IHKA High only)
- MAX cooling (IHKA High only)
- Maximum heating
- Residual heat (IHKA High only)
- Defrost function (IHKA High only)
- Rear window heating
- Washer jet heating
- Air recirculation function
- Automatic air recirculation
- Automatic air-recirculation control (IHKA High)
- Program for avoiding condensation on the window surfaces (IHKA High only)
- Convertible program (only E64)
- Independent ventilation function (IHKA High only)
- Auxiliary heater operation (optional equipment 536)
In the heating/air-conditioning system, the air-mass flow is first cooled and dried at the evaporator (provided the air conditioner is switched on). Then the airflow is heated to the required temperature at the heating system heat exchanger.
The maximum outlet temperature in the ventilation area is reached as follows:
- Set the rotary switch for temperature selection to maximum temperature (28 C)
Set temperature layering as follows with the CID:
- IHKA Basis:Stratification to ”red” (hotter)
- IHKA High:All 4 red bars must be displayed.
The evaporator temperature is regulated with the help of the evaporator temperature sensor and a controllable expansion valve. The evaporator temperature is set to the predefined specification of 2 C. Lower temperatures are not possible due to the risk of icing.
If the ”variable evaporator control” function has been encoded, the nominal evaporator temperature is calculated between 2 and 7 C. The specification depends on the ambient temperature, the ventilation temperature and the refrigerant pressure. A variable evaporator control reduces dehumidification. This reduces the risk of mucous membranes drying out.
Air distribution setting
Occupants have the possibility of allowing the air distribution to be decided by the automatic program (AUTO button). Alternatively, individual, personal settings are possible through manual selection (defrost, ventilation, footwell).For the best possible operation of the air distribution, it is important for the manually adjustable air vents to be open.
Air flow control
The air flow control is dependent on the following settings and control actions:
Sunlight adaptation (solar sensor, IHKA High only)
The influence on IHKA regulation by the solar sensor is assigned separately to the driver's and the passenger's side.
The following functions are modified when automatic mode is activated:
MAX cooling (IHKA High only)
The MAX button makes it possible for the user to select maximum cooling with just one press of a button on the IHKA control panel.
When the MAX button is pressed, all functions, including the defrost function, are deactivated. The air-conditioning function is activated (if it was not already activated) and defined settings are selected (e.g. temperature control is deactivated, the dual water valve is closed).
If the rotary switch for temperature selection is turned to the end stop, maximum heating is activated. Regulation of the interior temperature is suspended. Predefined settings are selected (e.g. temperature of heating system heat exchanger regulated to maximum setting 90 C).
Residual heat (IHKA High only)
The residual-heat function makes it possible to utilise the waste heat from the engine to heat the vehicle interior when the engine is not running. The additional coolant pump is activated to circulate the water.
Defrost function (IHKA High only)
The defrost function is activated with the defrost button in the IHKA control panel. This opens the defroster flap (on the inside in front of the windscreen) fully. The fresh-air/air-recirculation flaps move to the ”fresh air” position. All other flaps are closed. The blower can be set manually.
Heated rear window
The heated rear window is switched on by pressing the heated rear window button in the IHKA control panel. The function indicator light in the button lights up.
The heated rear window is switched off when the button is pressed again, or automatically when the heating period of 10 or 17 minutes has expired. If the button is pressed again during the heating phase, the afterheating phase (approx. 5 minutes) starts.
Washer jet heating
The washer jets are heated, depending on the ambient temperature (under 3 C). The IHKA control unit actuates the nozzle heating.
Press the OFF button to completely switch the IHKA control panel off.
Air recirculation function
In the air recirculation function, in the event of high pollution, e.g. in a traffic jam, the supply of fresh air can be blocked. The air from the vehicle interior is permanently recirculated.To prevent condensation, the air recirculation function is limited in duration.
Automatic air recirculation
In automatic mode, the system will automatically switch to air-recirculation mode if an extreme cooling output is called for. This allows the vehicle interior to be cooled more quickly. Air from the vehicle interior that has already been cooled is fed through the evaporator again. This reduces the temperature level much faster than it would in normal operation.
Automatic air-recirculation mode initially runs for 12 minutes in full air-recirculation mode and then continuously in partially fresh-air mode (fresh-air flap opening angle: approx. 10 ).
Automatic air-recirculation control (IHKA High)
If the AUC sensor detects an excessively high level of emissions in the environment, the IHKA control unit will automatically switch to air-recirculation mode.
Because of the lack of a fresh-air supply, air-recirculation mode is only available for a limited period of time:
When the engine is started and the AUC function activated, fresh air is always selected for approx. 40 seconds due to the warming phase of the AUC sensor.
Program for avoiding condensation on the window surfaces (IHKA High only)
Measures to prevent condensation on the windscreen depend on a number of conditions:
The IHKA control unit evaluates condensation sensor signal (air humidity). If condensation on the windscreen is imminent, the following measures are initiated in turn until the condensation has been eliminated. If a measure proves to be ineffective, the next measure is initiated. Once successful, the measures previously performed are reversed step-by-step in reverse order.
Measures against condensation on windscreen:
Convertible program (only E64)
The convertible program is activated in the factory. (this factory setting can be deactivated win the Car and Key Memory)
The convertible program comprises the following functions:
In the convertible program, the blower speed can be changed manually on the IHKA control panel. The automatic flap control remains active (no change to flap position). If the convertible program is active and the flap positions are changed with the CID and controller, the convertible program will be deactivated. This means that manual settings will be assumed, unchanged settings will revert to those that the air-conditioning system had before the convertible top was closed. The convertible program can be completely reactivated by pressing the AUTO button.
Independent ventilation function
The independent ventilation function is activated either via the Central Information Display (CID) or via Telestart (through the Car Access System (CAS)). There are 2 ways of activating the system via the CID: Direct operation or programming using the timer.
If the independent ventilation function is programmed via the timer, the independent ventilation function will only be available at exterior temperatures above 15 C.
The battery charge level is constantly monitored by the intelligent battery sensor throughout the independent ventilation function. If the necessary charge level is not maintained, the IHKA control unit will deactivate the independent ventilation function.
Auxiliary heater operation (optional equipment 536)
The auxiliary heater operation is activated either via the Central Information Display (CID) or via Telestart (through the Car Access System (CAS)). There are 2 ways of switching the system on via the CID: Direct operation or programming using the timer.
Conditions required for switching the independent heater on:
The independent heater has the following functions:
Auxiliary heating with running engine (pseudo auxiliary heating)
When the auxiliary heating is running, pseudo auxiliary heating mode is started when the engine is started. During pseudo auxiliary heating mode, the indicator lamp for the independent heating is off. If the engine temperature is greater than or equal to the temperature of the independent heating circuit, the system will change from pseudo auxiliary heating mode to auxiliary heating. These two modes differ in that only the independent heater circuit is used in pseudo auxiliary heating mode, while in auxiliary heating mode the larger heater circuit is used.
Telestart (via CAS)
The average range of the Telestart transmitter is approx. 150 meters. The CAS forwards the signal from the Telestart transmitter through the body CAN to the following control units:
Low‐voltage cutout (via DME/DDE)
The battery's state of charge is constantly monitored by the intelligent battery sensor throughout the auxiliary heating operation. If the necessary state of charge is not maintained, the IHKA control unit will deactivate the auxiliary heating operation.
The hardware of the IHKA control panel are available temperature displays in °C (Celsius) or in °F (Fahrenheit).
No liability can be accepted for printing or other faults. Subject to changes of a technical nature