汽车专业英语课件-4cha

复习,提问（教师说发动机配气机构汉语部件名称，同学回答英文名称）翻译VVT英文片段,学习内容,本次课学习内容、目标和重点难点,学习目标,难点重点,EFIsystemsGDI,1.掌握EFI的原理、主要组成系统部件的英文名称；掌握EFI的分类英文术语2.掌握GDI系统的控制原理和控制模式,1.重点为记忆英文专业术语、GDI控制原理2.难点需要记忆的生词偏多3.汉译准确表达也是难点,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,2.6.1NewWordsandPhrases,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,1.TypesofPulseFuelInjectionSystemsIntheelectronicfuelinjectionsystem,theinjectormaybeopenedandclosedbyelectricalsignals.Thisisapulsefuelinjectionsystem.Thepulseinjectionsystemisusuallyelectronicallycontrolled.Althoughthereareanumberofdesigndifferencesbetweenvariouspulsefuelinjectionsystems,theoperatingprinciplesareverysimilar.Thethrottlebodyinjectionsystem(Fig.2-9left)usesanassemblycontainingoneortwofuelinjectors.Theassemblyismountedattheentrancetotheintakemanifoldandinjectsfuelaheadofthethrottlevalve.Thesesystemsarealsocalledsingle-pointinjection（SPI）orcentralfuelinjection.Multi-pointinjectionsystems(Fig.2-9right),alsocalledmulti-portinjection（MPI）systems,deliverfuelattheengineintakeportsneartheintakevalves.,2.6.2Text,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,2.PulseFuelInjectionSystemComponentsThetypicalpulseinjectionsystem(Fig.2-10)canbebrokenintothreesubsystems:Airinductionsystem.Thesystemconsistsofanaircleanerassembly,throttlebody,andintakemanifold(Fig.2-10).Thethrottlebodysectioncontainsthethrottlevalve,whichisopenedandclosedbythedrivertocontroltheamountofairenteringtheintakemanifold.Fueldeliverysystem.Thefueldeliverysystem(Fig.2-10）providesthefuelwhichmixeswiththeair.ThemainpartsofthesystemareshowninFig.2-11andFig.2-12.Pressureisprovidedbyanelectricfuelpump.,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-9Single-pointinjection(left)andmulti-pointinjectionsystem(right),Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-10Atypicalpulseinjectionsystem,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-11Fueldeliverysystem,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-12Fueldeliverysystemofacar,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-12Fueldeliverysystemofacar,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Electroniccontrolsystem.Thecomputerreceivessignalsfromanumberofsensorswhenevertheengineisrunning(Fig.2-13).Fromthisinput,thecomputerevaluatesenginefuelneedsandadjustsinjectorpulsewidthaccordingly.Moderncomputerscontrolmanyotherenginesystemsinadditiontothefuelinjectors（Fig.2-10）.Thesensorsmonitorvariousenginefunctionsandfeedthisinformationtothecomputer.Thenumberandtypesofsensorsvarywiththesystem.,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Fig.2-13Engineelectroniccontrolsystem,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Theoxygensensormonitorstheamountofoxygenintheenginesexhaustgases.Thecomputerusessignalsfromtheoxygensensortocontroltheair-fuelmixture.Theoxygensensorisgenerallymountedintheexhaustmanifold.TheenginespeedsensormonitorsengineRPM.Manyspeedsensorsaremountedinthedistributor.Inothersystems,thespeedsensorismountedsothatitcanmonitorcrankshaftorcamshaftrotation.Thesespeedsensorsalsoindicatethecrankshaftandcamshaftpositionsothatthecomputercanopentheinjectorbeforetheintakevalveopens.Throttlepositionisrelayedtothecomputerbythethrottlepositionsensor.Throttlepositionsensorsareinstalledonthethrottlebody.,Chapter2InternalCombustionEngine2.6GasolineElectronicFuelInjectionSystem,Engineloadistransmittedtothecomputerbymeansofanintakemanifoldabsolutepressuresensor.Thesensorconvertsmanifoldvacuumintoasmallelectricalsignal.Thisinputallowsthecomputertoincreasefuelsupplywhentheengineisunderloadandneedsarichermixture,anddecreasefuelsupplywhenengineloadislight.Everyinjectionsystemhasatemperaturesensortomeasureenginecoolanttemperature.Manyinjectionsystemshaveanadditionalsensortomeasurethetemperatureoftheincomingair.Somelatemodelfuelinjectionsystemsmonitortheamountofairenteringtheenginebyusinganairflowsensor（Fig.2-10）.ThecomputertakesthisinputandcomparesitwithengineRPMandmanifoldvacuumtodeterminetheamountoffueltoinject.Therearethreetypesofairflowsensors,theheatedwire,theairvalveandtheKarmannvortex.,Chapter2InternalCombustionEngine2.7Gasolinedirectinjection,2.7.1NewWordsandPhrases,Chapter2InternalCombustionEngine2.7Gasolinedirectinjection,AlthoughMPIprovidesadrasticimprovementinresponseandcombustionquality,itisstilllimitedduetofuelandairmixingpriortoenteringthecylinder.Tofurtherincreasethrottleresponseandcombustionefficiency,whileloweringfuelconsumptionandincreasingoutput,systemsmayusedirectinjection.Gasolinedirectinjectionenginesareengineeredtoinjectthegasolinedirectlyintothecylinderinamannersimilartodieseldirectinjectionengines(Fig.2-14).Directinjectionisdesignedtogetbetterfueleconomy.Thisisaccomplishedbyenablingcombustionofanultra-leanmixtureundermanyoperatingconditions.Directinjectionisalsodesignedtoallowhighercompressionratios,deliveringhigherperformancewithlowerfuelconsumption.Currently,directinjectiongasolineenginesarebeingdeployedthroughouttheworldinpassengercars.,2.7.2Text,Chapter2InternalCombustionEngine2.7Gasolinedirectinjection,Fig.2-14Gasolinedirectinjection,Avarietyofair-fuelmixturescanbecreatedaccordingtochangesinthefuelinjectiontiming.TheGDIengineprovidesbothlowerfuelconsumptionandhigheroutput.Thisisachievedwiththeuseoftwocombustionmodes.ThesetwomodesarerepresentedinFigure2-15.,Chapter2InternalCombustionEngine2.7Gasolinedirectinjection,Figure2-15MitsubishiGDIusestwocombustionmodes,Chapter2InternalCombustionEngine2.7Gasolinedirectinjection,Ultra-leanCombustionMode.Undermostnormaldrivingconditions,uptospeedsof120km/h,theMitsubishiGDIengineoperatesinultra-leancombustionmode,resultinginlessfuelconsumption.Inthismode,fuelinjectionoccursatthelatterstageofthecompressionstrokeandignitionoccursatanultra-leanair-fuelratioof30-40.Thisoperatingmodeisalsocalledasstratified-chargemode.SuperiorOutputMode.WhentheGDIengineisoperatingwithhigherloadsorathigherspeeds,fuelinjectiontakesplaceduringtheintakestroke.Thisoptimizescombustionbyensurin