SAE-J-2255-1996

SAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.QUESTIONSREGARDINGTHISDOCUMENT:[phone]FAX:[phone]TOPLACEADOCUMENTORDER;[phone]FAX:[phone]SAEWEBADDRESS—ThisDocumenthasnotchangedotherthantoputitintothenewSAETechnicalStandardsBoardFormat.1.Scope—ThisSAERecommendedPracticeprovidesinstructionsandtestproceduresformeasuringairconsumptionofairbrakedvehiclesequippedwithAntilockBrakeSystems(ABS)usedonhighways.1.1Purpose—Thisdocumentprovidesamethodtodeterminetheairconsumptionofhighwayvehicleswhenthebrakesystemmustmaintainperformancewhentheservicebrakecontrolisappliedforlongperiodsoftime.2.References2.1ApplicablePublications—Thefollowingpublicationsformapartofthisspecificationtotheextentspecifiedherein.Unlessotherwisespecified,thelatestissueofSAEpublicationsshallapply.2.1.1SAEPUBLICATION—AvailablefromSAE,400CommonwealthDrive,Warrendale,PA15096-0001.SAEJ1626—Braking,Stability,andControlPerformanceTestProcedure2.1.2FMVSSPUBLICATION—AvailablefromTheSuperintendentofDocuments,U.S.GovernmentPrintingOffice,Washington,DC20402.FederalMotorVehicleSafetyStandard1212.2RelatedPublications—Thefollowingpublicationsareprovidedforinformationpurposesonlyandarenotarequiredpartofthisdocument.2.2.1SAEPUBLICATIONS—AvailablefromSAE,400CommonwealthDrive,Warrendale,PA15096-0001.SAEJ813—AutomotiveAirBrakeReservoirVolumeSAEJ992—BrakeSystemPerformanceRequirementsSAEJ1911—TestProcedureforAirReservoirCapacitySAEJ2255IssuedMAY96-2-3.InstrumentationandEquipment3.1Instrumentation3.1.1Timingdeviceaccuratetowithin1%ofelapsedtime.3.1.2Pressuremeasuringsystemsaccuratetowithin5%ofthepressurereadings.3.2Equipment3.2.1Dummycouplerforattachmenttotheemergencylineforsealingthesupply(emergency)line.3.2.2A820cc(50in3)reservoirattachedtothecontrol/serviceline.3.2.3Adevicetoisolatethesystemfromtheaircompressor,(i.e.,electronicsolenoid,valve,etc.).3.2.4Pressuretransducers.4.VehicleCondition4.1Allairconnectionsshallbeassembledsothattheleakageratefortheentireairsystem,withallservicebrakesappliedatapressureof655kPa±33kPa(95psi±5psi),shallnotbemorethan6.9kPa(1psi)perminute.Forleakagerateevaluationoftowingvehicles,the820cc(50in3)reservoircouplershallbeconnectedtotherearcontrollinecouplerandthedummycouplertotherearsupplylinecoupler.Fortruck-tractors,theaircontrolknobsinthecabshallbepositionedsothattheparkingbrakesarereleasedandairflowstocouplersprovidedfortowingtrailers.Fortrailers,thesupplylinecouplershallbepressurizedto654kPa±33kPa(95psi±5psi).4.2Brakesshallbeburnished.4.3Brakes(includingthosewithautomaticadjusters)aretobeadjustedtothevehiclemanufacturer'spublishedinstructions.Wheretheinstructionsdifferfornewandburnishedlinings,theadjustmentspecifiedforburnishedliningsshallbefollowed.4.4Ifthevehicleisequippedwithanyairreservoir(s)tooperatesystemsotherthanthebrakesystem,suchreservoirsshallbeisolated.Allairoperatedaccessoriesotherthanofthebrakesystemshallbeintheoffposition.4.5Recordtherequiredvehicleinformationonthetestdatasheet(seeFigure1andFigure2).5.TestConditions5.1TestLanes—3.7m(12ft)wide,152.4m(500ft)straightandlevelwithaPFC=0.5orless(wetJenniteingoodcondition).5.2VehiclePosition—Centeredinlaneattheinitiationofbraking.5.3Steering—Drivertosteerasnecessaryduringbrakingtomaintainvehiclecontrol.5.4FullApply—Brakeapplicationwheretherateofairpressureriseatthefootvalveisfrom0to483kPa(60psi)orgreaterwithin0.2s.5.5InitialBrakeTemperature—AsrequiredbyFMVSS121.65to93°C(150to200°F)inthebrakeliningofthehottestbrake.InstallthermocouplesperFMVSS121(seeFigure3).SAEJ2255IssuedMAY96-3-FIGURE1—TRUCK/TRACTOR/BUSDATASHEETSAEJ2255IssuedMAY96-4-FIGURE2—TRAILER/DOLLYDATASHEETSAEJ2255IssuedMAY96-5-FIGURE3—TYPICALPLUGTYPETHERMOCOUPLEINSTALLATION5.6BrakeWarming—Ifnecessary,warmthebrakesbymakingsnubsfrom64to32km/h(40to20mph)at3m/s(10ft/s)decelerationatone-mileintervals.5.7Transmission—Neutral(orclutchdepressed).5.8FullLoad—VehicleatGVWR.5.8.1TRACTORS—Areloadedwithanunbrakedcontroltrailer,asdefinedinSAEJ1626.5.8.2TRAILERS—AreloadedtoGAWR.5.8.3DOLLIES—AreloadedtoGAWRwithanunbrakedcontroltrailer,asdefinedinSAEJ1626.5.9SurfaceFriction—Peakfrictioncoefficient(PFC)asidentifiedinSAEJ1626.SAEJ2255IssuedMAY96-6-6.Truck,Truck-Tractors,andBuses6.1Installapressuretransducerattheoutputofthefootvalveandineachreservoirsystem.6.2Ontowingve