英国泽迪亚克实习报告题目及解答

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1、Contents1)Sketchanddescribeafuelinjectorforamodernmarinedieselengine.2)Detailwhatfaultsarelikelytobeexperiencedwiththeinjector.3)Explaintheprocedureforaccuratelysettingstheinjectorliftingpressure.Answerforfirstquestion:Thefueldeliveredthefuelpumpstotheinjectors.For

2、thefueltoburncompletelyatthecorrecttimeitmustbebrokenupintotinydropletsinaprocessasknowasatomization.Thesetinydropletsshouldbepenetratingforenoughintothecombustionspacesothattheymixwiththeoxygen.Fuelinjectorsachievethisbymakinguseofaspringloadedneedlevalve.Thefuelu

3、nderpressurefromthefuelpumpisfeddowntheinjectorbodytoachamberinthenozzlejustabovewheretheneedlevalveisheldhardagainstitisseatbyastrongspring.Asthefuelpumpplungerrisesinthebarrel,pressurebuildsupinthechamber,actingontheundersideofneedle.Whenthisforceovercomesthedown

4、wardforceexertedbythespring,theneedlevalvestartstoopen.Thefuelnowactsonthesettingareaofthevalveandincreasethelift.Asthishappens,fuelflowsintospaceundertheneedleandisforcedthroughthesmallholesinthenozzle,whereitemergesasan“atomizedspray”.Attheendofdelivery,thepressu

5、redropssharplyandthespringclosestheneedlevalvesmartly.InM/VHYUNDAIMECURYfuelinjectorisclosetypewithmechanicaloperatedclosingneedlebyaspringloadingwhichallowshighpressurefueltoanozzlewhichisprovidedwithoneormoreatomizerholes.Injectorsarelocatedinthecylindercoverandt

6、hreearefittedtoproduceeffectivecombustionwithanevenheatingeffect.Itconsistsofavalveheadandvalvehousing.Fittedwithinthevalvehousingisanon-returnvalveandaneedleandneedleguidewithapressurespringandanozzle.Fuelwhichleaksinconsequenceofthenozzleneedleclearanceisdrainedt

7、hroughleakagefuelpipeviaconnectiontotheleakagefuelpipefromtheinjectionvalve.Fueloilwhichpossiblyleaksbetweennozzlebodyandnozzleholderrisesandappearsattheup-earsattheupperedgeofthecylindercover.Workingoffuelinjector:1.Theelectricalfueloilprimarypumpcirculatespreheat

8、edoilthroughthefuelpump.2.Fueloilisledathighpressuretothethreeinjectionvalvesviainjectioncontrolunit.1.Thefuelquantityrequiredforinjectionflowsth