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

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Manual air recirculation modeWith the manual air conditioner, the driver isresponsible for controlling and operating airrecirculation mode.The driver decides on when and for how long.After pressing the air recirculation button, theflaps are adjusted pneumatically with vacuum.With automatic air conditioners, too, airrecirculation mode is mainly selected manuallyby the driver.In this case, the fresh air/air recirculation flap isadjusted electrically by means of a positioningmotor.What both systems have in common is– Fresh air flap closed= air recirculation flap open– Fresh air flap open= air recirculation flap closedThe air recirculation flap positioning motor isalso used to adjust the air flow flap.Air recirculation button – manual airconditionerOFFECONAUTOAir recirculation button – automatic airconditionerPositioning motorAir flow flap208_118207_043Fresh airrecirculation flapSeveral versions of automatic air conditionersalready control air recirculation modeautomatically.As soon as pollutants enter the ambient air, thefresh air supply is blocked.Cabin airThese systems have additional systemcomponents.Vehicle air conditioningin air recirculation mode – electrically operated208_09061
Temperature controlAutomatically controlled air recirculationmodeNOxFresh airintakeCombination filterAir qualitysensor G238Signal tooperating anddisplay unit E87CS2H S 2SO2+C H 6 14CO-Airborne pollutantsC H 6 6208_105In systems with a manually operated airrecirculation mode, the changeover is logicallynot performed by the driver until an odournuisance occurs, by which time the air inside thevehicle will have already been fouled.In systems with an automatic air recirculationmode, the vehicle ventilation system will beclosed as soon as pollutants in the air have beendetected (by a sensor), i.e. before an odournuisance occurs. The automatic air recirculationfunction can be switched on and off manually.The system components– Air quality sensor G238An electronic component which is located inthe area of the fresh air intake upstream ofthe combination filter.– Combination filterThe combination filter replaces the dust andpollen filter. It comprises a particle filter containingactivated charcoal.The operating principleA gas sensor detects pollutants in the ambientair. When a high pollutant concentration occurs,the air conditioner control unit implements thesignal which the gas sensor generates bychanging over from fresh air mode torecirculation mode.If the pollutant concentration drops below agiven threshold, then fresh air is again suppliedto the vehicle interior.Manual function switch on/offbutton208_108Operating and display unit with automaticallycontrolled air recirculation modeWhat pollutants are detected?The primary pollutants contained in the exhaustgases of the petrol engine are:CO - Carbon monoxideC 6 H 14 - HexaneC 6 H 6 - BenzeneC 7 H 16 - n-heptaneIn exhaust gases of diesel engines:NO X - Nitrogen oxidesSO 2 - Sulphur dioxideH 2 S - Hydrogen sulphideCS 2 - Carbon bisulphide62
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 14 and 15: Auxiliary signals for temperature c
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 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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