Brief component description: Sensors
The following sensors are installed in the heating and air conditioning system:
- Interior-temperature sensor
An interior temperature sensor (not with forced ventilation) is installed in the IHKA controls.
The interior temperature sensor measures the air temperature in the vehicle interior.
- Refrigerant pressure sensor
The refrigerant pressure sensor is located in the pressure line between the condenser and the evaporator. Depending on the sensor signal, the air-conditioning compressor is regulated by the IHKA control unit in the event of excessive refrigerant pressure.
The junction box electronics supply the refrigerant pressure sensor with voltage. The data are evaluated in the junction box electronics (JBE). The prepared data is sent across the body CAN (K-CAN) to the IHKA control unit.
- Evaporator temperature sensor
The evaporator temperature sensor picks up the outlet temperature of the cooled air at the evaporator to prevent freezing of the evaporator.
The evaporator temperature sensor is directly connected to the IHKA control unit.
- rain, light and precipitation solar sensor (IHKA-High only)
The solar sensor and condensation sensor are parts of the rain-light-solar-condensation sensor. The solar sensor enables the integrated automatic heating and air conditioning system (IHKA) to take account of solar radiation. The solar sensor measures the sunlight on the vehicle. The sunlight on the driver's side and front passenger side are detected separately.
The condensation sensor enables the IHKA to detect window condensation at an early stage, even before the driver can detect it. Counter-measures (program for the prevention of condensation) can be taken in good time without the need for driver intervention.
The condensation sensor provides the following information:
- Temperature on inside of the windscreen
- Air humidity on inside of the windscreen
The sensor data is processed in the evaluation electronics unit of the rain, light and precipitation solar sensor. The rain-light-solar-condensation sensor provides the data via the LIN bus. The junction box electronics (JBE) adopts the signals into the corresponding CAN message and sends them. The IHKA control unit is equipment attached to the bus on the K-CAN. If the rain and/or condensation sensor system fails, a fault entry is made in the junction box electronics (JBE).
- Sensor for automatic air recirculation mode
The AUC sensor is a metal oxide sensor. This sensor is highly sensitive to various smells and pollutants that are typical of traffic.
The AUC sensor evaluates the concentration of carbon monoxide and nitrogen oxides in the intake fresh air. The AUC sensor converts the detected air quality (also referred as air grade) into an electrical signal. To simplify processing of the information, the air quality in divided into 10 grades:
- Grade 0 to 10 (clean to severely contaminated)
The AUC sensor transmits the corresponding grade as a digital signal via the LIN bus to the junction box electronics (JBE). The junction box electronics transmit the digital signal via the CAN bus to the IHKA control unit. If the automatic air recirculation control sensor measures an emission value that is too high, an automatic changeover recirculated air operation takes place via the IHKA control unit.
- 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 center ventilating flap on the driver's side. The ventilation temperature sensor is directly connected to the IHKA control unit
- Footwell temperature sensor
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 IHKA control unit.