中职-人民交通版《-汽车专业英语(第3版)》单元三 汽车发动机 课件【陈淑芬、袁亮-主编】.ppt

汽车专业英语（第3版）陈淑芬袁亮主编李磊杨二杰王利平副主编朱军丛书总主审全国中等职业学校课程改革规划新教材

汽车商标汽车及其历史汽车发动机汽车底盘单元一单元二单元三单元四

汽车电气设备汽车车身汽车使用说明书及维修手册汽车检测与维修设备单元五单元六单元七单元八

汽车维护汽车检测与维修新能源汽车概述汽车商务接待单元九单元十单元十一单元十二

单元三活塞连杆组故障诊断与修复汽车发动机

学习目标完成本学习任务后，你应该能：1.了解发动机的基本结构及其工作过程；2.掌握发动机专业术语的英语表达；3.对相关内容进行阅读和翻译；4.对发动机结构上的英文单词或词汇进行辨认；5.正确完成课后练习。建议学时6学时

TextTheengineisaself-containedpowerunitwhichconvertstheheatenergyoffuelintomechanicalenergyformovingthevehicle.Becausefuelisburnedwithintheengine，itisknownasaninternalcombustionengine.Intheinternalcombustionengine，theburningofthefuelcausesarapidriseincylinderpressurewhichisconvertedtousefulmechanicalenergybythepistonandcrankshaft.Themajorityofenginesinvehiclestodayarefour-stroke，spark-ignitioninternalcombustionengines.Theenginefourstrokes(Fig.3-1)areIntake，Compression，PowerandExhaust.ThepistontravelsdownontheIntakestroke，upontheCompressionstroke，downonthePowerstrokeandupontheExhauststroke.ConstructionandOperationPrincipleofEngine

TextConstructionandOperationPrincipleofEngineFig.3-1EngineFourStrokes

TextIntakeOntheintakestrokethepistonispulleddowninthecylinderbythecrankshaftandconnectingrod.Duringthistimetheintakevalveopensandthefuel-airmixtureisdrawnintothecylinder.Whenthepistonreachesthebottomoftheintakestroke，theintakevalvecloses，trappingtheair-fuelmixtureinthecylinder.CompressionThepistonmovesupandcompressesthetrappedairfuelmixturethatwasbroughtinbytheintakestroke.Theamountthatthemixtureiscompressedisdeterminedbythecompressionratiooftheengine.Thecompressionratioontheaverageengineisintherangeof8∶1to10∶1.ConstructionandOperationPrincipleofEngine

TextPowerThesp