Designation:D6812−04a(Reapproved2014)AnAmericanNationalStandardStandardPracticeforGround-BasedOctaneRatingProceduresforTurbocharged/SuperchargedSparkIgnitionAircraftEngines1ThisstandardisissuedunderthefixeddesignationD6812;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginaladoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscriptepsilon(´)indicatesaneditorialchangesincethelastrevisionorreapproval.1.Scope1.1Thispracticecoversground-basedoctaneratingproce-duresforturbocharged/superchargedsparkignitionaircraftengines.Thispracticehasbeendevelopedtoallowthewidestrangeofapplicabilitypossiblebutmaynotbeappropriateforallenginetypes.Thispracticeisspecificallydirectedtoground-basedtestingandactualin-flightoctaneratingsmayproducesignificantlydifferentresults.1.2Thisstandarddoesnotpurporttoaddressallofthesafetyconcerns,ifany,associatedwithitsuse.Itistheresponsibilityoftheuserofthisstandardtoestablishappro-priatesafetyandhealthpracticesanddeterminetheapplica-bilityofregulatorylimitationspriortouse.2.ReferencedDocuments2.1ASTMStandards:2D2700TestMethodforMotorOctaneNumberofSpark-IgnitionEngineFuel3.Terminology3.1Definitions:3.1.1aminenumberofreferencefuelsabove100,AN—determinedintermsoftheweightpercentof3-methylphenylamineinreferencegradeisooctane(2,2,4-trimethylpentane).Forexample,5%of3-methylphenylamineinreferencegradeisooctanehasanaminenumberif105(AN105).Noattempthasbeenmadetocorrelateperformancenumberofleadedreferencefuelstotheaminenumberofunleadedreferencefuels,andnoneisimplied.3.1.2engineoctanerequirement—onefullnumbergreaterthanthemaximumnumberthatresultsinknock(graphicknockleveldescriptionscanbeseeninAnnexA1).Forexample,atestengineknocksonprimaryreferencefuelswith98and99motoroctanenumbers.Thetestenginedoesnotknockonaprimaryreferencefuelwitha100motoroctanenumber.Themaximummotoroctanenumberthatresultsinknockis99sothemotoroctanerequirementis100.Ifatestengineknocksonareferencefuelwitha3-amin...
