saej1737v002

SURFACEVEHICLERECOMMENDEDPRACTICETestProceduretoDeterminetheHydrocarbonLossesfromFuelTubes,Hoses,Fittings,andFuelLineAssembliesbyRecirculationSAETechnicalStandardsBoardRulesprovidethat:“ThisreportispublishedbySAEtoadvancethestateoftechnicalandengineeringsciences.Theuseofthisreportisentirelyvoluntary,anditsapplicabilityandsuitabilityforanyparticularuse,includinganypatentinfringementarisingtherefrom,isthesoleresponsibilityoftheuser.”SAEreviewseachtechnicalreportatleasteveryfiveyearsatwhichtimeitmaybereaffirmed,revised,orcancelled.SAEinvitesyourwrittencommentsandsuggestions.Copyright©2004SAEInternationalAllrightsreserved.Nopartofthispublicationmaybereproduced,storedinaretrievalsystemortransmitted,inanyformorbyanymeans,electronic,mechanical,photocopying,recording,orotherwise,withoutthepriorwrittenpermissionofSAE.TOPLACEADOCUMENTORDER:Tel:877-606-7323(insideUSAandCanada)Tel:724-776-4970(outsideUSA)Fax:724-776-0790Email:custsvc@sae.orgSAEWEBADDRESS:http://www.sae.orgIssued1997-08Revised2004-11SupersedingJ1737AUG1997®J1737REV.NOV2004TABLEOFCONTENTS1.Scope.....................................................................................................................................32.References.............................................................................................................................33.BackgroundInformation.........................................................................................................43.1GeneralComments–ThisProcedure...................................................................................43.2OtherMeasurementTechniques...........................................................................................43.3MeasuringSteady-StateConditions......................................................................................53.3.1TimetoReachSteady-State..................................................................................................63.3.2DeterminingSteady-State......................................................................................................63.4TestConditions......................................................................................................................83.4.1Temperature...........................................................................................................................83.4.2TypeofFuel...........................................................................................................................83.4.3Pressure.................................................................................................................................93.4.4WallThickness.......................................................................................................................93.4.5ConstructionofthePart.......................................................................................................103.4.6MoistureContent..................................................................................................................103.4.7VariationofTestSpecimen..................................................................................................103.5UnitsofMeasurement..........................................................................................................103.5.1TypesofUnitsofMeasurement...........................................................................................103.5.2CautionsAboutUnitsofMeasurement................................................................................114.ApparatusandEquipment...................................................................................................124.1ElementsofApparatus.........................................................................................................124.1.1InertGasforPressurizingFuel............................................................................................124.1.2PressureRegulatorandGauge...........................................................................................124.1.3FuelContainer......................................................................................................................124.1.4HeaterfortheTestFuel.......................................................................................................144.1.5RecirculationPumpandRegulatorforFuelFlowRate.......................................................144.1.6TubingtoRouteTestFuel....................................................................................................144.1.7TestCell...............................................................................................................................14SAEJ1737RevisedNOV2004-2-4.1.8TestSpecimen-General.......................................................................................................144.1.9MountingTestSpecimen.....................................................................................................144.1.10LengthChangeMeasurement.............................................................................................164.1.11HeatingMantleforTestCell................................................................................................164.1.12CarrierGasforFuelVapors.................................................................................................164.1.13TubingforCarrierGas.........................................................................................................164.1.14PumpandFlowRegulatorforCarrierGas..........................................................................174.1.15PressureRegulator..............................................................................................................174.1.16CollectionDevice.................................................................................................................174.1.17ActivatedCharcoal...............................................................................................................184.2OtherEquipment..................................................................................................................184.2.1Balance................................................................................................................................184.2.2FuelHandlingItems.............................................................................................................194.2.3Tools.....................................................................................................................................194.2.4SafetyItems.........................................................................................................................195.Chemicals............................................................................................................................195.1FuelMixtures........................................................................................................................195.2Nitrogen(Dry).......................................................................................................................195.3ActivatedCharcoal...............................................................................................................196.SafetyEquipmentandFacilities...........................................................................................206.1VaporControlDevice...........................................................................................................206.2Gloves..................................................................................................................................206.3SafetyGlasses.....................................................................................................................206.4TemperatureControls..........................................................................................................206.5PressureControls................................................................................................................207.TestProcedure.....................................................................................................................207.1TestSpecimenPreparation.................................................................................................217.2PreconditioningTestSpecimen...........................................................................................217.3MountingTestSpecimen.....................................................................................................217.4PreparingCharcoalCanisters..............................................................................................227.4.1CharcoalAdsorptiveCapacity.............................................................................................227.4.2DryTheCharcoal.................................................................................................................227.4.3CharcoalIntoTheCanisters................................................................................................227.4.4WeightTheCanisters...........................................................................................................237.4.5AttachCanisterstoApparatus.............................................................................................237.5PreparingFuelMixture.........................................................................................................237.6FuelFlow..............................................................................................................................237.7SetTestTemperature..........................................................................................................237.7.1TypicalTestTemperatures..................................................................................................237.7.2RecordtheTestTemperature..............................................................................................237.7.3SuggestedProcedureforUsingTemperaturesLessthan60°C........................................247.8PressuretheTestFuel.........................................................................................................247.9StartingTest.........................................................................................................................247.10ConductingtheTest.............................................................................................................247.10.1First8Hours.........................................................................................................................24SAEJ1737RevisedNOV2004-3-7.10.2WeightheCharcoalCanisters.............................................................................................257.11ShuttingDowntheTestApparatus......................................................................................258.Calculations..........................................................................................................................258.1WeightGain.........................................................................................................................258.2ConfirmDimensionsatEndofTest.....................................................................................268.3CalculatePermeationRateatEndofTest...........................................................................269.ReportingResults.................................................................................................................279.1UnitsofMeasurement..........................................................................................................279.2IdentifyingResults................................................................................................................279.3AdditionalInformation..........................................................................................................2710.Notes....................................................................................................................................2810.1MarginalIndicia....................................................................................................................28AppendixA..........................................................................................................................................29A.1CalculationofAdsorptiveCapacityoftheCharcoal.............................................................29A.1.1TestPreparation...................................................................................................................29A.1.2TestProcedure.....................................................................................................................29A.1.3AdsorptiveCapacity.............................................................................................................29A.2DeterminationofAdsorptiveEfficiencyofCanisters............................................................301.ScopeThisSAERecommendedPracticeisintendedforthedeterminationofthelossesofhydrocarbonfluids,bypermeationthroughcomponentwallsaswellasthrough"microleaks"atinterfacesofassembledcomponentswhilecontrollingtemperatureandpressureindependentlyofeachother.Thisisachievedinarecirculatingsysteminwhichelementsofatestfuelthatpermeatethroughthewallsofatestspecimenandmigratethroughtheinterfacesaretransportedbyacontrolledflowofdrynitrogentoapointwheretheyaremeasured.Thatmeasurementpointisadevice,suchasacanistercontainingactivatedcharcoalorothermeansofcollectionoraccumulationwherethehydrocarbonlossesarethenmeasuredbyweightchangeoranalyzedbysomeothersuitablemeans.2.References2.1ApplicablePublicationThefollowingpublicationformsapartofthespecificationtotheextentspecifiedherein.Unlessotherwiseindicated,thelatestrevisionofSAEpublicationsshallapply.2.1.1SAEPUBLICATIONSAvailablefromSAE,400CommonwealthDrive,Warrendale,PA15096-0001.SAEJ30—FuelandOilHosesSAEJ1527—MarineFuelHosesSAEJ1681—Gasoline,AlcoholandDieselSurrogatesforMaterialTestingSAEJ1737RevisedNOV2004-4-3.BackgroundInformationGovernmentregulationscontinuetoevolveandestablishmorestringentstandardsforlimitingthetotalquantityofevaporativehydrocarbonemissionsthatarepermittedtocomefromavehicle.Besidesindicatingmuchlowerlevelsofemissionstobeachieved,theyarealsoestablishingschedulesanddeadlinesforachievingthoselevels.Hydrocarbonevaporativeemissionscanarisefrommanysourcesonavehicle.Amajorpartofthoseareassociatedwiththefuelandfuelvaporsystems.Thesehydrocarbonemissionscancomefromthemanydifferentpartsofthefuelsystemandfromitsgeneralusage:a.Refuelingthevehicleb.Breathinglossesfromtheengine’sairintakesystemandfromthefuelsystemventthroughcanistersc.Permeationofthefuelconstituentsthroughthewallsofthecomponentsthatcontainthefueld.Migrationofthefuelorvaporthroughconnections,interfaces,andanyotherpotentialleakpathsofthefuelsystem(microleaks)3.1GeneralComment–ThisProcedureThisdocumentdescribesaprocedurethathasseveraladvantagesovertheothermeasurementtechniquesthatarecommonlyused:•Ithasabetterlevelofsensitivityneededformeasuringverylowratesofpermeation.•It’sbettersuitedtoberunathighertemperatures(upto60°C).Thisallowssteadystatetobeachievedmorequicklyandyieldshighermeasuredratesofpermeationthatareeasiertouseforcomparisonamongcomponents.•Whenalcoholblendfuelsareused,thisprocedurecanaccountforallthealcoholthat’spresentinthepermeate.(Doesn’taccountforallifyouuseaFIDtomeasure).•Thisprocedureprovidesaneasiermeanstomaintainthepropercompositionlevelsinalcoholblendfuels.•Fuelisbeingcirculatedthroughthesystem/componentbeingtestedasthepermeationmeasurementsarebeingmade.3.2OtherMeasurementTechniques3.2.1WEIGHTLOSSTECHNIQUESInthepast,permeabilityofmaterialsorcomponentshasbeenmeasuredbyafairlysimpleweight-losstechnique.Ingeneral,thesehaveinvolvedfillingacomponent(oratestassemblyconsistingofacomponentandareservoir)withfuelandthenmeasuringanyweightchangesthatoccuroveraprescribedperiodoftimeandunderaspecificsetofconditions.Themostcommonoftheselong-usedtechniquesarethosedescribedbySAEJ30andJ1527;canbeusedtomeasureverysmallpermeationrates,buttheyhavelimitationswhenratesarehigher,temperaturesarehigherbecausetestfluidchemistrychangessignificantlyduringthetestduetoselectivepermeationofconstituants.Also,thesetwotechniquesdonotinvolvecirculatingfuelasthepermeationismeasured.SAEJ1737RevisedNOV2004-5-3.2.2SEALEDHOUSINGEVAPORATIVEDETERMINATION(S.H.E.D.)UNITSOneoftheprimarytechniquesformeasurementofvehiclehydrocarbonemissionsistheSealedHousingEvaporativeDetermination(S.H.E.D.)test.Thistestusesanenclosedchambersthatcontaintheitembeingtested(vehicle,system,orcomponent).Theenvironmentinsidethechamberiscontrolledandperiodicallyanalyzedtodeterminethequantitiesofhydrocarbonsthatarepresent.ThistechniqueisspecifiedintheoverallgoverningregulationsfromtheEnvironmentalProtectionAgency(EPA)andtheCaliforniaAirResourcesBoard(CARB).Itisusedprimarilyforthreeoftheaspectsofthehydrocarbonemissions:statictesting,normaloperation,andrefueling;largecomponents(e.g.,tanks)andfuelsystemstypicallyutilizethistechniqueaswell.SmallerSHEDunits(miniSHEDandmicroSHED)arenormallyusedtomeasurepermeabilityofmaterialsorsmallercomponentsandtheperformanceofspecificinterfaces.TheS.H.E.D.unithassomelimitationswhenmeasuringpermeationratesforcomponents,especiallywhenalcoholblendfuelsareinvolved.•AveragetemperatureforthetypicaldirunalcyclesfortheSHEDproceduresareactuallyverylow(30°to35°C)comparedtowhatistypicallyusedintheproceduredescribedinthisdocument(upto60°C).•Ifalcohol-blendtestfluidsareused,theSHEDdetectiontechnique(FID)doesnotaccountfortheentireMDSSthealcoholthat’spresentinthepermeate.ThisisbecausetheFIDiscalibratedusingpropanetogivetheresponsefactorof1.0forpropane.Otherconstituentsintheshedthenhaveresponsefactorslessthanorgreaterthan1.0.Mostfuelhydrocarbonshavearesponsefactorthatiscloseenoughto1.0thatthisisasmallerror.However,alcoholssuchasethanolhasaresponsefactorthatissignificantlylessthan1.0.Bycomparison,therecirculationproceduredescribedinthisRecommendedPracticeaccountsforallalcoholthat’sinthepermeate.•SincethetemperaturefluctuatesduringthetypicaltemperaturecyclefortheSHEDprocedure,theemissionsmeasuredwilltendtolagbehindmeasurementsthataremadebyaprocedurethatusesaconstanttemperatureprocedure.ThesepointsmeanthattheemissionsratesmeasuredusingtheproceduredescribedinthisdocumentaremuchlargerthanthosemeasuredintheSHEDunit.Sincethisprocedureyieldslargervalues,itiseasiertousethantheSHEDproceduretodistinguishbetweentwopartsorsmallsystemsthathaveverylowpermeationrates.3.3MeasuringSteady-StateConditionsWhenratesofpermeationaremeasured,theinitialperformanceofacomponentormaterialisnotthesameastheeventualequilibriumvalue.Ittakesacertainamountoftimeforthemigrationofthefuelthroughthewallorattheinterfacestoachieveitssteady-staterateafterfirstexposuretothefuel.Also,withsomematerials,therecanbeothercomponentspresent(e.g.,plasticizer)thataredrivenoffbythefuel,temperature,orothertestconditions.Timemustbeallowedfortheseotheremanationstostopcontributingtoanyweight-lossmeasurements.Theremayalsobeachangeincrystallinitywhenmeasuringatelevatedtemperatures.SAEJ1737RevisedNOV2004-6-Itisimportanttonotethatthebetteramaterialorcomponent'sresistancetopermeation,thelongerittakestoachievethesteady-stateconditions.Forthisreason,thesenewmeasurementtechniquesusetestconditionsthatcausehighpermeationrates.Thehigherthepermeationrate,thesoonerequilibriumisachieved.Theamountoftimespentintheexpensivepermeationmeasurementunitcanbeshortenedbypreconditioningthespecimeninalowcostpreconditioningunit.Refertosection7.2fordetailsconcerningthis.3.3.1TIMETOREACHSTEADY-STATEForanindicationoftheamountoftimeinvolvedinachievingsteady-stateconditions,experiencehasshownthatitcantakeseveralhundredhoursforequilibriumpermeationratetobeachievedatthetesttemperatureof60°Cusingalcohol-blendtestfluids.Iftemperaturesarelowerthan60°Coriftestfuelsare&ldq