I摘要柴油機(jī)運(yùn)轉(zhuǎn)時(shí)氣缸內(nèi)的燃燒溫度達(dá)到1800到2000，瞬時(shí)溫度高達(dá)3000，與高溫燃?xì)庀嗷ソ佑|的零件（如缸蓋，活塞，氣缸，氣閥，噴油器等）受到強(qiáng)烈的加熱，如不加以適當(dāng)?shù)睦鋮s，發(fā)動(dòng)機(jī)會(huì)過熱，充氣系數(shù)下降，燃燒不正常，發(fā)生早燃和爆燃現(xiàn)象，與高溫接觸零件過熱，導(dǎo)致材料機(jī)械性能降低，和產(chǎn)生嚴(yán)重的熱應(yīng)力，導(dǎo)致變形和裂紋，另外溫度過高會(huì)使得機(jī)油變質(zhì)，燒損和結(jié)焦失去潤(rùn)滑性能，破壞潤(rùn)滑油膜，零件的摩擦和磨損加劇，從而導(dǎo)致發(fā)動(dòng)機(jī)的動(dòng)力性，可靠性，經(jīng)濟(jì)性，耐久性，全面惡化。如果系統(tǒng)的冷卻能力過強(qiáng)，機(jī)油被燃油稀釋（即因缸壁過冷，可燃混合氣體在缸壁冷凝并聚集，沖刷缸筒上的潤(rùn)滑油膜，未蒸發(fā)的燃油經(jīng)缸壁流到油底殼，稀釋機(jī)油），同時(shí)惡化混合氣體形成及燃燒，增加機(jī)油粘度和摩擦效率，造成零件間的磨損加劇，摩擦損失增加，柴油機(jī)工作粗暴，另外通過冷卻系統(tǒng)帶走的熱量是燃油燃燒的熱量，一般約占燃燒熱量的20%-30%，這是一種損失，如果冷卻過強(qiáng)，散熱損失增加，會(huì)降低發(fā)動(dòng)機(jī)的經(jīng)濟(jì)性。因此發(fā)動(dòng)機(jī)過冷或者過熱（即發(fā)動(dòng)機(jī)冷卻能力過強(qiáng)或者過弱）都會(huì)對(duì)發(fā)動(dòng)機(jī)的動(dòng)力性，經(jīng)濟(jì)性，工作可靠性帶來不利的影響。因此設(shè)計(jì)良好的冷卻系統(tǒng)，能夠保證發(fā)動(dòng)機(jī)始終處于最適宜的溫度下工作，已獲得較高的發(fā)動(dòng)機(jī)經(jīng)濟(jì)性能，動(dòng)力性能，工作可靠性指標(biāo)等。冷卻系統(tǒng)的功用就是使發(fā)動(dòng)機(jī)在各種工況下都保持在適當(dāng)?shù)臏囟确秶鷥?nèi)，冷卻系統(tǒng)既要防止發(fā)動(dòng)機(jī)過熱，又要防止冬季發(fā)動(dòng)機(jī)過冷，在冷態(tài)下的發(fā)動(dòng)機(jī)啟動(dòng)之后，冷卻系統(tǒng)還要保證發(fā)動(dòng)機(jī)迅速升溫，盡快達(dá)到正常的工作溫度。關(guān)鍵詞：散熱器；風(fēng)扇；冷卻水泵；硅油風(fēng)扇離合器；節(jié)溫器IIAbstractCylinderdieselenginerunninginsidethecombustiontemperaturereaches1800to2000,theinstantaneoustemperatureupto3000,andthehightemperaturegascomponentsincontactwitheachother(suchascylinderhead,piston,cylinder,valve,injector,etc.)bythestrongheating,Ifnotproperlycooled,theenginewilloverheat,inflatablecoefficientdecreased,abnormalcombustion,burningandexplodingphenomenonoccurredearly,withthehightemperaturecontactpartsoverheat,resultinginlowermechanicalpropertiesofmaterials,andsevereheatstress,leadingtodeformationandcrackInaddition,theoiltemperatureistoohighwillcausedeterioration,lossofcokeburningandlubricatingproperties,destructionofoilfilm,partofthefrictionandwearincreased,resultinginenginepower,reliability,economy,durability,overalldeterioration.Ifthesystemscoolingcapacityistoostrong,oilisthefueldilution(ie,coolingduetocylinderwall,combustiblegasmixtureinthecylinderwall,condensationandaggregationoferosiononthecylinderlubricatingoilfilm,notbyevaporationofthefuelflowtothesumpcylinderwall,dilutedoil),whiledeteriorationofgasmixtureformationandcombustion,increasingefficiencyofoilviscosityandfriction,causingincreasedwearbetweenparts,frictionlossesincreaseingrossenginework,whiletheheatthroughthecoolingsystemisthefuelburnawaytheheat,generallyaboutburningcalories-30%to20%,whichisaloss,ifthecoolingistoostrong,increasetheheatlosswillreducetheengineseconomy.Sotheenginecoldorhot(ie,enginecoolingistoostrongortooweak)willbetheengineofpower,economy,adverselyaffectthereliabilityofwork.Therefore,well-designedcoolingsystemensurestheenginealwaysworkunderthemostsuitabletemperature,theenginehasbeenhigheconomicperformance,dynamicperformance,operationalreliabilityindicators.Functionofthecoolingsystemistomaketheengineinvariousoperatingconditionsaremaintainedattheappropriatetemperaturerange,coolingsystems,itisnecessarytopreventtheengineoverheating,andalsotopreventthewintercoldengine,theengineundercoldIIIstart,thecoolingsystemalsoensurethattheenginequicklywarminguptonormaloperatingtemperatureasquicklyaspossible.Keywords:radiator；fan；coolingwaterpump；siliconoilfanclutch；Thermostats遼寧工程技術(shù)大學(xué)畢業(yè)設(shè)計(jì)目錄1緒論.11.1汽車發(fā)動(dòng)機(jī)冷卻系統(tǒng)概述.11.2汽車發(fā)動(dòng)機(jī)冷卻系統(tǒng)的發(fā)展和現(xiàn)狀.21.3汽車發(fā)動(dòng)機(jī)冷卻系統(tǒng)向高效化發(fā)展.52散熱器的設(shè)計(jì).62.1發(fā)動(dòng)機(jī)散熱量計(jì)算.62.2散熱器材料的選擇.62.3結(jié)構(gòu)設(shè)計(jì)及選擇.63節(jié)溫器的設(shè)計(jì).1