Part I
64 01 04 (090) Integrated heating control and climate control
Introduction
In this BMW Service Technology, the following heating and air-conditioning systems are described:
- E8x, E9x
- Integrated heating control (IHR)
[System overview ...]
- Integrated heating/air-conditioning regulation (IHKR)
[System overview ...]
- Integrated IHKA with left-right separation for driver's side and front passenger side
[System overview ...]
- Overview of IHK, IHKR and IHKA components
[System overview ...]
- E7x
- Integrated automatic heating and air-conditioning system (IHKA), Basic
[System overview ...]
- IHKA High with left-right separation for driver's side and front passenger side
[System overview ...]
- IHKA High with automatic rear air-conditioning system (FKA) with separate settings for the driver's side and front passenger side and left-right separation in the rear passenger compartment.
[System overview ...]
- Overview of IHKA components in the Basic and High versions
[System overview ...]
IHR, IHKR and IHKA in the E8x, E9x
The IHR, IHKR and IHKA are heating and air conditioning systems that regulate the temperature of the air. The IHKA has separate settings for the driver's side and passenger side.
E8x
The 1 Series is equipped as standard with the integrated heating control (IHR). The integrated automatic heating/air-conditioning system (IHKA) is available as optional equipment (option 534).
- From 12/2004, the integrated heating / air-conditioning control (IHKR) is available as optional equipment for all four-cylinder models (option 530).
The IKHR is the standard equipment for the six-cylinder models.
E9x
The 3 Series is equipped as standard with integrated heating / air-conditioning regulation (IHKR). The integrated automatic heating/air-conditioning system (IHKA) is available as optional equipment (option 534).
New features of the IHR/IHKR/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 separate component and is installed in the heating and air-conditioning unit. The electric auxiliary heater consists of electrically heated heating chains. Air is heated directly by these heating chains and is then fed through the air vents into the passenger compartment. In principle, the electric auxiliary heater works like an electric radiator.
The electric auxiliary heater accelerates the heating of the passenger compartment, especially at low ambient temperatures and during the cold-start phase.
- LIN bus (Local Interconnect Network bus)
A LIN bus serves to actuate flap motors and the electric auxiliary heater in the heating/air-conditioning system.
- Convertible program (E93 only)
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.
- Air distribution flap motor and microswitch (IHR, IHKR only)
The air distribution flap motor replaces the mechanical actuation of the central kinematics with a cam disc. The central kinematics are still used to mechanically adjust the air distribution flaps. Air distribution (defrost, ventilation, footwell) is selected with the air distribution selector wheel in the IHR/IHKR control panel.
The microswitch records the current position of the cam disc and thus the position of the air distribution flap motor.
Differences between the heating and air conditioning systems (E8x, E9x):
Integrated automatic heating / air conditioning (IHKA) in the E7x
The IHKA in the X5 is a water-controlled heating and air-conditioning system.
The X5 is equipped as standard with the IHKA Basic. The Basic version does not provide for separate settings for the driver and front passenger sides.
The IHKA High with separate settings for the driver and front passenger sides is available as optional equipment (option 534).
The automatic rear air-conditioning system (FKA) available as optional equipment (option 4NB).
An auxiliary heating/ventilation system is available as optional equipment for the 3rd row of seats (option 4NC).
New features on IHKA High:
- Integrated automatic heating and air-conditioning system (IHKA) High with automatic rear air-conditioning system (FKA)
In addition to the separate settings for the driver's and front passenger sides, separate settings are also possible for the left and right sides in the rear seats (option 4NB).
The rear seat passengers can set the temperature and blower speed separately for the left and right sides on the FKA control panel.
- Rain/light solar sensor (IHKA High only)
The solar sensor is a component of the rain light solar sensor (RLSS).
Differences between the heating and air-conditioning systems (E7x):
Brief component description
- IHR, IHKR and IHKA control panel/control unit
The control panel and control unit together form a single component. There are different versions for integrated heating control, integrated heating/air-conditioning control and IHKA.
- E8x, E9x: control panel/control unit [more ...]
- E7x: control panel/control unit [more ...]
- Control panel/control unit for automatic rear air-conditioning system, E7x only
The automatic rear air-conditioning system (FKA) is available in the X5 as additional equipment with the IHKA. The FKA controls the rear air-conditioning system/heating.
[more ...]
Sensors:
- Interior temperature sensor (only IHKA)
The force-ventilated interior temperature sensor with interior temperature sensor blower is fitted in the IHKA controls. The interior temperature sensor measures the air temperature drawn in from the passenger compartment by the integrated interior temperature sensor blower.
Substitute value for the sensor: 20 °C
E7x
The separate settings for the left and right sides in the rear passenger compartment mean that the rear heating and air-conditioning control panel has an automatically ventilated interior temperature sensor.
- Solar sensor (only IHKA)
The solar sensor consists of a photosensor (E7x: 2 photosensors) and detects external sources of light and/or heat (e.g. radiation of the sun) that influence the climate in the passenger compartment.
Sunlight compensation is only active in the automatic program.
- E8x, E9x (IHKA only)
The solar sensor supplies the IHKA control unit with an analogue signal that depend on the intensity of the sunlight.
The solar sensor is clipped into the middle of the dashboard.
- E7x (IHKA High only)
The solar sensor is a component of the rain light solar sensor (RLSS). The RLSS measures external sources of light and heat (e.g. sunlight) for left and right sides of the vehicle. The sensor data are processed in the evaluation electronics of the rain/light solar sensor. Signal path: RLSS -> LIN bus -> FZD (roof function centre; serves as data interface) -> IHKA control unit
The rain/light solar sensor is attached to the inside of the windscreen within the wiper range of the windscreen wipers.
- Sensor for automatic air recirculation control
- E8x, E9x IHKA only
- E7x IHKA High only
The AUC sensor is fitted on the microfilter compartment. The AUC sensor detects the following pollutant emissions from spark-ignition and diesel engines:
- Hydrocarbons (CH)
- carbon monoxide (CO)
- Nitrogen oxides (nitrogen monoxide NO, nitrogen dioxide NO2)
The junction box supplies the AUC sensor with voltage. The junction box electronics evaluate the data of the AUC sensor. The junction box electronics unit transmits relevant data to the IHKA controls (via the K CAN).
- Condensation sensor (only IHKA)
- E8x, E9x IHKA only
- E7x IHKA High only
The condensation sensor measures the air humidity on the windscreen in the passenger compartment. The condensation sensor is able to detect condensation on the windscreen before it becomes visible. The condensation sensor draws its power supply from the roof control panel. The FZD evaluates the condensation sensor data. The FZD sends appropriate data to the IHKA control unit (via the K CAN). Measures to avoid condensation on the window surfaces are only initiated in automatic program.
[more ...]
- Evaporator temperature sensor (IHKR, IHKA only)
The evaporator temperature sensor measures the outlet temperature of the air at the evaporator to prevent icing from occurring. The evaporator temperature sensor is directly connected to the IHKR/IHKA control unit.
Substitute value for the sensor: -2 °C
- Ventilation temperature sensor
A sensor is integrated into the heating and air-conditioning unit to measure the ventilation temperature. The ventilation temperature sensor measures the delivery temperature directly at the centre ventilating flap on the driver's side. The ventilation temperature sensor is directly connected to the IHR/IHKR/IHKA control unit.
E7x
If the IHKA High is fitted, there are 2 ventilation sensors (on the ventilation flaps for the driver's and front passenger sides).
Substitute value for the sensor: 20 °C
- E7x with rear heating and air conditioning system
One sensor is fitted at each of the left and right rear air outlets in the centre console.
- Footwell temperature sensor
- E8x, E9x
A sensor is integrated into the heating and air-conditioning unit to measure the footwell temperature. The footwell temperature sensor measures the blow-out temperature directly at the footwell flap on the driver's side. The footwell temperature sensor is directly connected to the IHR/IHKR/IHKA control unit.
Substitute value for the sensor: 20 °C
- E7x with rear heating and air conditioning system
One sensor is attached to each of the left and right footwell air outlet in the rear compartment.
- Heating heat exchanger sensor
E7x
The sensor is integrated in the heating and air conditioning system. On the IHKA Basic, the sensor measures the blow-out 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 drivers side and for the front passenger side. The heating system heat exchanger sensor is directly connected to the IHKA control unit.
Substitute value for the sensor: 55 °C
- Refrigerant pressure sensor (IHKR, IHKA only)
The refrigerant pressure sensor is located in the pressure line between the capacitor and the evaporator. Depending on the sensor signal, the output of the A/C compressor is reduced by the IHKR or IHKA control unit in the event of excessively high refrigerant pressure.
The junction box supplies the refrigerant pressure sensor with voltage. The data is evaluated in the junction box electronics. The evaluated data are transmitted to the IHKR or IHKA control unit via the body CAN (K CAN).
Actuators:
- Electric auxiliary heater (only vehicles with diesel engine)
The electric auxiliary heater works on the principle of PTC (positive temperature coefficient) and is installed in the heating and air-conditioning unit. The electric auxiliary heater directly heats up the air to adjust the temperature of the passenger compartment.
[more ...]
- Flap motors
The flap motors are controlled by the IHR/IHKR/IHKA control panel/control unit via the LIN bus.
E8x
- IHR/IHKR
The IHR/IHKR has 3 flap motors.
- IHKA until 09/2007
The IHKA has 6 flap motors (due to the left/right separation for the driver's side and the front passenger side and because there are no central kinematics).
- IHKA from 09/2007
7 flap motors are installed in the IHKA (the front stratification-flap motor is new).
E9x
- IHKR
The IHKR has 3 flap motors.
- IHKA
The IHKA has 8 flap motors (due to the left/right separation for the driver's side and the front passenger side, the additional stratification flap motors and because there are no central kinematics).
E7x
- IHKA Basic
The IHKA Basic has 6 flap motors.
- IHKA High
The IHKA High has 10 flap motors (due to the left/right separation for the driver's side and the front passenger side and the ventilation flap motors for the rear compartment).
- IHKA High with automatic rear air-conditioning system
With the IHKA High with automatic rear air-conditioning system (FKA), there are 13 flap motors (due to the separate settings for the left and right sides in the front and rear).
- Central kinematics (IHR, IHKR only)
The central kinematics are used to mechanically adjust the air distribution flaps. The central kinematics are driven by the air distribution flap motor. The air distribution flap motor is actuated by the IHR or IHKR control unit.
- Blower with blower output stage
The blower creates the necessary air mass flow. The blower is fitted after the fresh air/recirculated air flap in the heater/air conditioning system (pressing blower arrangement). The blower output stage is mounted directly at the housing of the blower motor. The blower output stage is actuated with a pulse-width modulated signal (PWM signal) by the IHR/IHKR/IHKA control unit. The blower output stage is not diagnosis-capable.
- A/C compressor with electric control valve (IHKR, IHKA only)
The air conditioning compressor compresses the refrigerant taken in by the evaporator. The refrigerant is pressed towards the capacitor. 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. The electric control valve on the A/C compressor influences the balance of forces on the swash plate and thus the adjustment of the displacement. For the purpose of load reduction, only the cooling power that is directly needed is generated.
The junction box electronics unit controls the control valve with a clocked voltage. The IHKR or IHKA controls specify the actuation.
NOTE: A/C compressor with magnetic coupling
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.
- Evaporator (IHKR, IHKA only)
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 auxiliary water pump serves to make sure that the coolant flow rate needed in the heater circuit is maintained, even at low engine speeds. The auxiliary water pump is actuated by the junction box, from which it also draws its voltage supply. The IHR/IHKR/IHKA control unit emits the signal for switching the auxiliary water pump on/off (via the K CAN).
- Water valve
E7x
The water valve operates electromagnetically and meters the coolant flow rate to the heating system heat exchanger as it is needed. This regulates the air temperature for heating the passenger compartment (heating and air conditioning that regulates water temperature).
On the IHKA High, a dual water valve is used for the left/right separation of the heating system heat exchanger. The JBE controls the water valve.
- Radiator fan
The radiator fan and the engine cooling are also required for cooling the condenser. The radiator fan is actuated by the DME/DDE.
Signal path:
Integrated heating/air-conditioning control and/or IHKA control unit -> K-CAN -> junction box electronics (serves as data interface) -> PT-CAN -> DME/DDE -> radiator fan
- Condenser with integrated dryer flask (IHKR, IHKA only)
In the capacitor, gaseous refrigerant is converted into liquid refrigerant. In the integrated downstream dryer flask, any water present in the refrigerant circuit is bound. The desiccant insert can be exchanged.
- Expansion valve (IHKR, IHKA only)
The expansion valve controls the injection quantity into the evaporator. Only as much liquid refrigerant enters the evaporator as the evaporator is able to completely evaporate. Drops of liquid that have not been evaporated would cause damage in the A/C compressor. The expansion valve is fitted directly to the engine bulkhead.
Additional components:
- Microfilter
Fresh air for interior ventilation is fed through a microfilter.
- E8x, E9x: IHR, IHKR
When a filter renewal is needed, this will be indicated by the Condition Based Service (CBS) (until 03/2007).
from 03/2007: Filter renewal: see Service Booklet
- E7x: IHKA
Filter renewal: see Service Booklet
- Microfilter with activated carbon
A microfilter with activated carbon is built into the IHKA. The carbon canister makes an additional contribution to cleaning the fresh air that enters of gaseous pollutant emissions.
- E8x, E9x: IHKA
When a filter renewal is needed, this will be indicated by the Condition Based Service (CBS) (until 03/2007).
from 03/2007: Filter renewal: see Service Booklet
- E7x: IHKA
Filter renewal: see Service Booklet
- Stratification control and rear stratification control
- E7x IHKA High and E9x IHKA
The selected potentiometer setting is transposed into the flap position of the specific flap motor (front and rear stratification flap motor and rear ventilation flap motor).
- E7x IHKA High with automatic rear air-conditioning system
Due to the separate settings for the left and right sides in the rear, there are 2 rear stratification controls and 2 ventilation flap motors in the rear.
- LIN bus
A data line supplies all component on the LIN bus with the necessary control information. This data line also carries the status reports of the components back to the IHR/IHKR/IHKA control unit. The control unit controls the following components via the LIN bus:
- Electric auxiliary heater
- Flap motors
The following control units contribute to the operation of the IHR/IHKR/IHKA:
- SZM: Centre console control panel
The SZM is connected to the IHR/IHKR/IHKA control unit via a 14 pin connector. The IHR/IHKR/IHKA control unit serves as the interface between the SZM and the K CAN.
The IHR/IHKR/IHKA control unit assumes the following tasks for the SZM:
- Reading off settings made by pressing buttons
- Activating LEDs for function indicator lighting
- Dimming LEDs for function and locator lighting
- Forwarding relevant CAN messages
- JBE: Junction Box Electronics
The JBE is the data interface (= gateway) between the K CAN and the PT CAN. (K CAN = body controller area network; PT CAN = powertrain controller area network.)
The JBE receives input signals from some of the sensors and control units (e.g. AUC sensor, DME/DDE control unit, IHR/IHKR/IHKA control unit).
The junction box consists of the JBE and the power distribution box. Amongst other things, the power distribution box supplies power to the heated rear window. The JBE controls the heated rear window.
- M ASK or CCC or CHAMP: Multi audio system controller or Car Communication Computer or multimedia platform
The controller signals for selecting the menu are processed in the M ASK or CCC or CHAMP (multimedia platform: CHAMP; Central Head Unit and Multimedia Platform).
To actuate the CID (Central Information Display), the red-green-blue signals from the graphics processor are converted into digital signals.
- CAS: Car Access System
The CAS comprises the master key functions, amongst other things.
The CAS assigns a personalisation number to every master key. The CAS transfers the personalisation number to the IHKA control unit via the K CAN.
Key-based settings (Key Memory) are stored in the IHKA control unit.
When the vehicle is unlocked, the master key unit used is recognised. The settings stored for this unit are called up and executed. In the after-running period, the current settings are stored for the master key unit in use at that time.
- DME or DDE: Digital Engine Electronics and/or Digital Diesel Electronics
The DME/DDE actuates the radiator fan.
On vehicles with diesel engine, the DDE provides the electric auxiliary heater with information about the maximum electrical power available (with a pulse-width modulated signal). The maximum electrical power available depends on the load on the alternator.
- Control and display functions via controller and Central Information Display (IHKA only)
The following control and display functions are selected and activated with the controller in the CID (Central Information Display):
- Air distribution
The defroster flaps, ventilation flaps and footwell flaps can be individually set in the air distribution submenu.
- Automatic mode
The intensity of the IHKA can be set in the automatic program submenu. In other words, the automatic influence of the climate conditions outside the vehicle on the air mass and the opening angle of the flaps can be set to one of three different settings (low, medium, high).
- E7x with IHKA High
The settings can be selected and activated at the IHKA control panel.
- Automatic rear air-conditioning system
- E7x with IHKA High
The automatic rear air-conditioning system can be activated or deactivated in the "Automatic program" submenu.
The function "Use driver's settings" can be selected to adopt the (driver's) settings from the IHKA control panel for the FKA control panel.