Designation:D2700−14Designation:236/87StandardTestMethodforMotorOctaneNumberofSpark-IgnitionEngineFuel1ThisstandardisissuedunderthefixeddesignationD2700;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.ThisstandardhasbeenapprovedforusebyagenciesoftheU.S.DepartmentofDefense.1.Scope*1.1Thislaboratorytestmethodcoversthequantitativedeterminationoftheknockratingofliquidspark-ignitionenginefuelintermsofMotoroctanenumber,includingfuelsthatcontainupto25%v/vofethanol.However,thistestmethodmaynotbeapplicabletofuelandfuelcomponentsthatareprimarilyoxygenates.2Thesamplefuelistestedinastandardizedsinglecylinder,four-strokecycle,variablecom-pressionratio,carbureted,CFRengineruninaccordancewithadefinedsetofoperatingconditions.Theoctanenumberscaleisdefinedbythevolumetriccompositionofprimaryreferencefuelblends.Thesamplefuelknockintensityiscomparedtothatofoneormoreprimaryreferencefuelblends.TheoctanenumberoftheprimaryreferencefuelblendthatmatchestheknockintensityofthesamplefuelestablishestheMotoroctanenumber.1.2Theoctanenumberscalecoverstherangefrom0to120octanenumber,butthistestmethodhasaworkingrangefrom40to120octanenumber.Typicalcommercialfuelsproducedforautomotivespark-ignitionenginesrateinthe80to90Motoroctanenumberrange.Typicalcommercialfuelspro-ducedforaviationspark-ignitionenginesrateinthe98to102Motoroctanenumberrange.TestingofgasolineblendstocksorotherprocessstreammaterialscanproduceratingsatvariouslevelsthroughouttheMotoroctanenumberrange.1.3ThevaluesofoperatingconditionsarestatedinSIunitsandareconsideredstandard.Thevaluesinparenthesesarethehistoricalinch-poundsunits.ThestandardizedCFRenginemeasurementscontinuetobeininch-poundunitsonlybecauseoftheextensiveandexpensivetoolingthathasbeencreatedforthisequipment.1.4Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,i...
