汽车使用英语第三课.ppt

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1、Unit3InternalCombustionEngineOperatingPrinciplesNewWordspiston[5pistEn]n.活塞crankshaft[5krANkFB:ft]n.曲轴expel[iks5pel]n.排出valve[vAlv]n.气阀term[tE:m]n.术语bore[bC:]n.缸径revolution[7revE5lu:FEn]n.旋转,转数cycle[5saikl]n.循环knock[nCk]v.敲缸,敲打学习目标1、知识目标：熟悉发动机工作原理；掌握发动机原理的专业术语和词汇；2、技能目标：掌握发动机工作原理的专业术语和词汇；能进行相关内容的阅读

2、和翻译。NotestoText1、Thepressuredevelopedwithinthecombustionchamberisappliedtotheheadofapistontoproduceausablemechanicalforce,whichisthenconvertedintousefulmechanicalpower.燃烧室里急剧升高的气压作用于活塞头部产生了有用的机械力，然后转化成有用的机械功。2、Thepowerstroke“usesup”thegas,someansmustbeprovidedtoexpeltheburntgasandrechargethecylinde

3、rwithafreshpetrol-airmixture.做功冲程“耗尽”了高压气体，因此意味着汽缸必须能够排除燃烧废气并且重新补充新鲜的汽油-空气的混合气。3、Tocompletethefullcycleittakestworevolutionsofthecrankshaft.Eachstrokeisnamedaftertheactionitperforms—intake,compression,power,exhaustinthatorder.完成整个循环曲轴要转两圈。每一个冲程因为其作用而被命名—依次是进气，压缩、做功，排气。InternalCombustionEngineOperat

4、ingPrinciplesEngineisusedtoproducepower.Thechemicalenergyinfuelisconvertedtoheatbytheburningofthefuelatacontrolledrate.Thisprocessiscalledcombustion.Ifenginecombustionoccursinthepowerchamber,theengineiscalledinternalcombustionengine.Ifcombustiontakesplaceoutsidethecylinder,theengineiscalledanextern

5、alcombustionengine.Engineusedinautomobilesareinternalcombustionheatengines.Heatenergyreleasedinthecombustionchamberraisesthetemperatureofthecombustiongasesinthechamber.Theincreaseingastemperaturecausesthepressureofthegasestoincrease.Thepressuredevelopedwithinthecombustionchamberisappliedtotheheadof

6、apistontoproduceausablemechanicalforce,whichisthenconvertedintousefulmechanicalpower.[1]Linkingthepistonbyaconnectingrodtoacrankshaftcausesthegastorotatetheshaftthroughhalfaturn.Thepowerstroke“usesup”thegas,someansmustbeprovidedtoexpeltheburntgasandrechargethecylinderwithafreshpetrol-airmixture.[2]

7、Thiscontrolofgasmovementisthedutyofthevalves:aninletvalveallowsthenewmixturetoenterattherighttimeandanexhaustvalveletsouttheburntgasafterthegashasdoneitsjob.Enginetermsare:TDC(TopDeadCenter):thepositionofth