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

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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
Temperature controlPositioning motorIn a manual air conditioner, air-ducting flapssuch as– the temperature flap– the central flap– the footwell/defrost flapare adjusted individually by the driver by meansof Bowden cables.In the automatically controlled air conditioner,the flaps are operated by electrically activatedpositioning motors. The air recirculation flap isalso positioning motor operated.208_091The positioning motors are always positionedlevel with the flap axis on the heater/airconditioner .All motors receive the corresponding controlsignals from the air conditioner control unit.Each positioning motor has a potentiometer. Thepotentiometer signals the position of the flap tothe control unit in the form of a feedback value.Thus, the electrical output signals are convertedto mechanical quantities by means of positioningmotors (actuators).208_1151 positioning motoreach for- temperature flap- central flap208_116- footwell/defrostPositioning motor for fresh airrecirculation flap and air flow flapElectrical circuitAir conditionercontrol unitThe flaps have different adjustmentmechanisms.The arrangement of the cranks andangle of rotation are always referred toa particular flap.- + 5VMSenderinformationPositioningmotor withpotentiometer208_09252
Page 1 and 2: System controlAt high (increasing)
Page 4 and 5: Radiator fan control unit J293The r
Page 6 and 7: Automatic controlFresh air intake d
Page 8 and 9: Actuators(for system control andtem
Page 10 and 11: Actuators/sensors on a heater/air c
Page 12 and 13: Dash panel temperature sensor G56 w
Page 16 and 17: Air ductingDash paneloutletFresh ai
Page 18 and 19: Fresh air208_111Air ducting in the
Page 20 and 21: Air distribution -split into two se
Page 22 and 23: The temperature can be set differet
Page 24 and 25: Manual air recirculation modeWith t
Page 26 and 27: Air quality sensor G238The sensor o
Page 28 and 29: Neither welding or brazing or solde
Page 30 and 31: An all-in-one system for checking,
Page 32 and 33: Refrigerants and plasticsRefrigeran
Page 34 and 35: Fault diagnosis through self-diagno
Page 36: Water vapour content of the airSatu

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

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