Self-Study Programme 208 Air Conditioner in the Motor ... - Volkspage

Auxiliary signals for temperature controlCombination processor indash panel insert12341/min x 1000567120100 14080 km/h 160601804020020220240t hn vnEngine control unitRadiatorcontrol unitAir conditionercontrol unitTo temperatureflapTo air flow flapCompressorHeater/airconditioner208_087With regard to temperature control, additionalinformation enhances comfort and is utilised forsystem control.These auxiliary signals are supplied by othervehicle control units and are processed by the airconditioner control unit.Important signals are:– ’Time parked ’t h– Road speed v– Engine speed n'Time parked' signal thTime parked=the time between switching off theignition and restarting the engineThis signal is utilised for adjusting thetemperature flap. When the engine is restarted,the control unit processes the ambienttemperature values stored before turning off theengine.Changes in measured data (e.g. due to radiantheat) are disregarded for control purposes.The comfort temperature is set quickly andexposure to subnormal temperatures is avoided.Road speed signal vIs required to control the air flow flap.The signal generated by the speedometer senderis utilised and implemented in the control unit. Athigher road speeds, the cross-section of the freshair inlet is reduced in order to keep the air flowinto the passenger cabin as steady as possible.Engine speed signal nThis signal provides information to the airconditioner control unit on actual engineoperation. It is required for system control (toswitch off the magnetic clutch), e.g. if there is noengine speed signal, the compressor is switchedoff.51