毕业设计外文翻译--变速器

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1、外文资料TransmissionsTransmissionshavetocompromiseoneitherridecomfortorefficiency,butanewapproachtothedogengagementgearboxcouldimproveboth.Withtighteningemissionsregulations,carmakersarenotjustconfiningtheireffortstoimprovingcombustionandafter-treatment.Manyarefind

2、ingthatmodernenginesaresoadvancedthatthebenefitsofsomeenginetechnologiesaresmallcomparedtothehugedevelopmentcostsinvolved.It'simportanttolookatthewholevehicleinordertoimproveemissions.Asthesecondmostexpensivepieceofkitinthecar,thetransmissionisthelogicalnextpla

3、cetolook.Ofalltransmissiontechnologies,themanualgearboxisthemostefficient;around96percentoftheenergythatisputincomesoutoftheotherend.Butnoteveryonecandriveoneorwantsto.Becauseyouhavetodiptheclutchpedal,it'slesscomfortabletodriveinheavytraffic.Itmakesthedriverti

4、redandthetorqueinterruptions'head-nodeffectonpassengerscanbewearing.Thedriver'sclutchcontrolandcorrespondingtorqueinterruptionsarealsothemanual'sweakpoint.Whenacceleratingupthroughthegearbox,eachup-shiftrequiresthedrivertocutthetorquemomentarilybyliftingthegasp

5、edalanddippingtheclutch.Itmayjusttakeasecondtocompletetheoperation,butduringthistimethevehicleislosingspeedandacceleration.Attheoppositeandofthespectrumisthetraditionalautomatic.Itsshiftqualityisgoodthankstoitstorqueconverter,butefficiencyisrelativelypoordespit

6、erecentadvances.Becauseofthis,alotofthecurrentresearchistryingtofindanefficientalternativetotheconventionalautomatic.Themaintechnologiesarecontinuouslyvariabletransmissions(CVTs);dualclutchtransmissions(DCTs)andautomatedmanualtransmissions(AMTs).Theyallofferdif

7、ferentbenefitsovertheconventionalplanetaryautomatic.TheCVTusesabeltchainortoroidalshapeddishdrivetovaryaninfinitenumberofgearratios.Ithasimprovedefficiencyandcostwhencomparedtoconventionalautomatics.Itsadvantagecomesfromitssimplicitu.Itconsistsofveryfewcomponen

8、ts;usuallyarubberormetal-linkbelt;ahydraulicallyoperateddrivingpulley,amechanicaltorque-sensingdrivingpulley,microprocessorsandsomesensors.Thetransmissionsworksbyvaryingthed