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1、Electronicpowersteeringsystem电子动力转向系统WhatitisElectricallypoweredsteeringusesanelectricmotortodriveeitherthepowersteeringhydraulicpumporthesteeringlinkagedirectly.Thepowersteeringfunctionisthereforeindependentofenginespeed,resultinginsignificantenergysavings.Howitworks:Conventionalpowersteeringsystemsuseanengineaccessorybelttodrivethepump,providingpressurizedfluidthatoperatesapistoninthepowersteeringgearoractuatortoassistthedriver.Inelectro-hydraulicsteering,oneelectricallypoweredsteeringconcept。
2、usesahighefficiencypumpdrivenbyanelectricmotor.Pumpspeedisregulatedbyanelectriccontrollertovarypumppressureandflow,providingsteeringeffortstailoredfordifferentdrivingsituations.Thepumpcanberunatlowspeedorshutofftoprovideenergysavingsduringstraightaheaddriving(whichismostofthetimeinmostworldmarkets).Directelectricsteeringusesanelectricmotorattachedtothesteeringrackviaagearmechanism(nopumporfluid).Avarietyofmotortypesandgeardrivesispossible.Amicroprocessorcontrolssteeringdynamicsanddrivereffort.In。
3、putsincludevehiclespeedandsteering,wheeltorque,angularpositionandturningrate.WorkingInDetail:Asteeringsensorislocatedontheinputshaftwhereitentersthegearboxhousing.Thesteeringsensorisactuallytwosensorsinone:atorquesensorthatconvertssteeringtorqueinputanditsdirectionintovoltagesignals,andarotationsensorthatconvertstherotationspeedanddirectionintovoltagesignals.Aninterfacecircuitthatsharesthesamehousingconvertsthesignalsfromthetorquesensorandrotationsensorintosignalsthecontrolelectronicscanprocess.。
4、Inputsfromthesteeringsensoraredigestedbyamicroprocessorcontrolunitthatalsomonitorsinputfromthevehicle'sspeedsensor.Thesensorinputsarethencomparedtodeterminehowmuchpowerassistisrequiredaccordingtoapreprogrammedforcemapinthecontrolunit'smemory.Thecontrolunitthensendsouttheappropriatecommandtothepowerunitwhichthensuppliestheelectricmotorwithcurrent.Themotorpushestheracktotherightorleftdependingonwhichwaythevoltageflows(reversingthecurrentreversesthedirectionthemotorspins).Increasingthecurrenttothem。
5、otorincreasestheamountofpowerassist.Thesystemhasthreeoperatingmodes:anormalcontrolmodeinwhichleftorrightpowerassistisprovidedinresponsetoinputfromthesteeringtorqueandrotationsensor'sinputs;areturncontrolmodewhichisusedtoassiststeeringreturnaftercompletingaturn;andadampercontrolmodethatchangeswithvehiclespeedtoimproveroadfeelanddampenkickback.Ifthesteeringwheelisturnedandheldinthefull-lockpositionandsteeringassistreachesamaximum,thecontrolunitreducescurrenttotheelectricmotortopreventanoverloadsit。
6、uationthatmightdamagethemotor.Thecontrolunitisalsodesignedtoprotectthemotoragainstvoltagesurgesfromafaultyalternatororchargingproblem.Theelectronicsteeringcontrolunitiscapableofself-diagnosingfaultsbymonitoringthesystem'sinputsandoutputs,andthedrivingcurrentoftheelectricmotor.Ifaproblemoccurs,thecontrolunitturnsthesystemoffbyactuatingafail-saferelayinthepowerunit.Thiseliminatesallpowerassist,causingthesystemtorevertbacktomanualsteering.AdashEPSwarninglightisalsoilluminatedtoalertthedriver.Todiag。
7、nosetheproblem,atechnicianjumpstheterminalsontheservicecheckconnectorandreadsoutthetroublecodes.clickheretoseeabiggerElectricpowersteeringsystemspromiseweightreduction,fuelsavingsandpackageflexibility,atnocostpenalty.Europe'shighfuelpricesandsmallervehiclesmakeafertiletestbedforelectricsteering,atechnologythatpromisesautomakersweightsavingsandfueleconomygains.Andinashorttime,electricsteeringwillmakeittotheU.S.,too.It'sjustjustamatteroftime,saysAlyBadawy,directorofresearchanddevelopmentforDelphiS。
8、aginawSteeringSystemsinSaginaw,Mich.Theissuewascostandthat'sbehindusnow.By2002hereintheU.S.thecostofelectricpowersteeringwillabsolutelybeawashoverhydraulic.Today,electricandhybrid-poweredvehicles(EV),includingToyota'sPriusandGM'sEV-1,aretheperfectdomainforelectricsteering.Butby2010,aTRWInc.internalstudyestimatesthatoneoutofeverythreecarsproducedintheworldwillbeequippedwithsomeformofelectrically-assistedsteering.TheCleveland-basedsupplierclaimsitsnewsteeringsystemscouldimprovefueleconomybyupto2mp。
9、g,whileenhancinghandling.Therearetruebottom-linebenefitsaswellforautomakersbyreducingoverallcostsanddecreasingassemblytime,sincethere'snoneedforpumps,hosesandfluids.Anotherclaimedadvantageisshorteneddevelopmenttime.Forinstance,aDelphigroupdevelopedE-TUNE,aride-and-handlingsoftwarepackagethatcanberunoffalaptopcomputer.Theycantakethatcomputerandplugitin,attachittothecontrollerandchangeallthehandlingparameters--effortlevel,returnability,damping--onthefly,Badawysays.Itusedtotakemonths.DelphihasoneOE。
10、Mcustomerthatshouldstartlow-volumeproductionin'99.Electricsteeringunitsarenormallyplacedinoneofthreepositions:column-drive,pinion-driveandrack-drive.Whichsystemwillbecomethenormisstillunclear.Shortterm,OEMswillchoosethesteeringsystemthatiseasiesttointegrateintoanexistingplatform.Obviously,greaterpotentialcomesfromdesigningthesystemintoanall-newplatform.Wehaveallthreedesignsunderconsideration,saysDr.HermanStrecker,groupvicepresidentofsteeringsystemsdivisionatZFinSchwaebischGmuend,Germany.It'suptot。
本文标题:Electronic-power-steering-system
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