汽车专业毕业论文翻译中英文（全）automobileemissions

《汽车专业毕业论文翻译中英文（全）automobileemissions》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、Lesson6-AutomobileEmissionsTrafficJamBackgroundInformationEmissionsfromanindividualcararegenerallylow,relativetothesmokestackimagemanypeopleassociatewithairpollutionbutinnumerouscitiesacrossthecountry,thepersonalautomobileisthesinglegreatestpolluterwithemiss

2、ionsfrommillionsofvehiclesontheroad.Drivingaprivatecarisprobablyatypicalcitizen’smost“polluting”dailyactivity.TheCleanAirActof1970gaveEPAbroadauthoritytoregulatemotorvehiclepollution,andtheagency’semissioncontrolpolicieshavebecomeprogressivelymorestringentsi

3、ncetheearly1970’s.EPAstandardsdictatehowmuchpollutionautosmayemitbutautomakersdecidehowtoachievethepollutionlimits.Theemissionreductionsofthe1970’scameaboutbecausefundamentalimprovementsinenginedesignplustheadditionofcharcoalcanisterstocollecthydrocarbonvapo

4、rsandexhaustgasrecirculationvalvestoreducenitrogenoxides.Theadventof“firstgeneration”catalyticconvertersin1975significantlyreducedhydrocarbonandcarbonmonoxideemissions.Theuseofconvertersprovidedahugeindirectbenefitaswell.Theconvertersleadtothewidespreadintro

5、ductionofunleadedgasolinebecauseleadinactivatesthecatalyst.Thisresultedindramaticreductionsinambientleadlevelsandalleviatedmanyseriousenvironmentalandhumanhealthconcernsassociatedwithleadpollution.Thenextmajormilestoneinvehicleemissioncontroltechnologycamein

6、1980-81.Inresponsetotighterstandards,manufacturersequippednewcarswithevenmoresophisticatedemissioncontrolsystems.Thesesystemsgenerallyincludea“three-way”catalyst,anon-boardcomputer,andanoxygensensor.Thisequipmenthelpsoptimizetheefficiencyofthecatalyticconver

7、ter.Provisionsofthe1990CleanAirActarefurtherreducingvehicleemissions.Mobilesourceprovisionsincludeeventightertailpipestandards,increaseddurability,improvedcontrolofevaporativeemissions,andcomputerizeddiagnosticsystemsthatidentifymalfunctioningemissioncontrol

8、s.Eventhougheffortsbygovernmentandindustryhavegreatlyreducedtypicalvehicleemissions,thenumberofmilesAmericansdrivehasmorethandoubledsince1970.Theincreaseintravelhasoffsetmuchoftheemissioncontrol