Volvo VN - Anti-Lock Braking System (Abs)

290OPERATION
ANTI-LOCKBRAKINGSYSTEM(ABS)
Thevehiclehasastandardbrakesystem,equippedwithanelectronicspeedmonitoring
andcontrolsystem,Anti-lockBrakingSystem(ABS).ABSmonitorswheelspeed
continuouslybutisnotinvolvedincontrollingthewheelspeedunlessthereisan
emergency.Innormalbrakingapplications,thestandardairbrakesystemisineffect.
WARNING
ForproperABSoperation,DONOT
changetiresizes.Thesizeofthe
tiresinstalledduringproductionare
programmedintotheelectroniccontrol
unit.Installingdifferentsizedtires
couldresultinareducedbrakeforce,
leadingtolongerstoppingdistancesor
accidents.
Thereisasensorinstalledineachwheelonamonitoredaxle.Thesensorstransmit
informationtotheelectroniccontrolunit(ECU).TheECUinterpretsthesignals
andcalculateswheelspeed,wheelretardingandavehiclereferencespeed.Ifthe
calculationsindicateawheellock-upsituation,asignalissentfromtheECUtothe
appropriateABSmodulatorvalvetoreducebrakingpressure.Duringemergency
braking,themodulatorvalvealternatelyreduces,increasesormaintainsairpressure
inthebrakechambertopreventwheellock-up.
Duringemergencyorreduced-tractionstops,fullydepressthefootbrakepedaluntil
thevehiclecomestoasafestop.DONOTPUMPthebrakepedal.Withthebrake
pedalfullydepressed,theABSwillcontrolallwheelstoprovidesteeringcontroland
areducedbrakingdistance.
AlthoughtheABSimprovesvehiclecontrolduringemergencybrakingsituations,the
operatorstillhastheresponsibilitytochangedrivingstylesdependingontheexisting
trafc,roadand/orweatherconditions.Forexample,theABScannotpreventan
accidentifthedriverisspeedingorfollowingtoocloselyonslipperysurfaces.