吉林大学毕业生毕业设计摘要汽车行业自诞生起到现在100多年间，汽车工业从无到有，发展速度惊人，相关技术不断创新发展，逐渐走向成熟。到目前为止，汽车动力性和排放性是各国关注的焦点。而发动机作为汽车的心脏，是汽车中最重要的组成部分，改进发动机结构或者使用新型燃料是目前汽车改善其动力性和排放性的主要方向。所以充分熟悉发动机构造特点，进行改进设计是研究开发发动机必不可少的环节。本设计以1987年中国第一汽车集团从美国克莱斯勒公司引进、由第一汽车集团生产的CA488系列发动机为例进行缩小缸径的改进设计，将CA488缩小缸径改进成CA485。通过对CA485发动机两大机构和四大系统的全面介绍，能够进一步了解汽油机的工作原理及其特点，从而对汽油机的内部构造进行全面的熟知。除此之外，本文还总结了国内外车用发动机发展现状，汽油机技术的发展趋势和汽车排放法规等内容。CA485为直列四缸、四冲程、火花点火式发动机，并采用顶置凸轮轴和齿形带正时等技术。关键词：汽油机，曲轴，连杆，飞轮，设计，活塞AbstractTheautomotiveindustrysinceitsbirthuntilthepresent100years,theautoindustryfromscratch,developingatanalarmingrate,relatedtechnologyinnovationanddevelopment,andgraduallymature.Sofar,vehiclepowerandemissionsisthefocusofnationalattention.Theengineastheheartofthecar,thecaristhemostimportantpartofimprovingthestructureoftheengineortheuseofnewfueliscurrentlythemaindirectionofthecartoimproveitspowerandemissionlines.Sofullyfamiliarwiththeinternalstructureoftheengine,theengineimprovementsisanessentialstepinresearch.Inthispaper,in1987ChinaFirstAutomobileGroupfromtheUnitedStatesChryslerintroducedbytheFirstAutomobileGroupproductionofCA488seriesengine,forexampletoforsmallerdiameterdesignimprovements,willCA488smallerdiameterimproveintoca485.throughthetwoinstitutionsandthefourengineCA485systematicandcomprehensiveintroductiontofurtherunderstandtheworkingprincipleofgasolineitscharacteristics,andthustheinternalstructureofthegasolineenginetoconductacomprehensiveknown.Inaddition,thepaperalsosummarizesthecurrentsituationofdomesticandforeignautomotiveenginedevelopment,thedevelopmenttrendofautomobilegasolineenginetechnologiesandemissionregulationsandsoon.CA485fortheinlinefour-cylinder,four-stroke,spark-ignitionengine,andtheuseofoverheadcamshaftandtoothedtimingbelttechnology.Keywords:gasolineengine,crankshaft,connectingrod,flywheel,design,piston目录TOC\o"1-2"\h\z\uHYPERLINK\l"_Toc451419535"第一章绪论PAGEREF_Toc451419535\h1HYPERLINK\l"_Toc451419536"1.1国内外车用发动机发展现状PAGEREF_Toc451419536\h1HYPERLIN