汽車專業(yè)英語(yǔ)-3-AUTOMOTIVE-LUBRICATION-SYSTEM

Chapter3AUTOMOTIVELUBRICATIONSYSTEM

背景知識(shí)

發(fā)動(dòng)機(jī)工作時(shí)，很多傳動(dòng)零件都是在很小的間隙下作高速相對(duì)運(yùn)動(dòng)的，如曲軸主軸頸與主軸承，曲柄銷與連桿軸承，凸輪軸頸與凸輪軸承，活塞、活塞環(huán)與氣缸壁面，配氣機(jī)構(gòu)各運(yùn)動(dòng)副及傳動(dòng)齒輪副等。盡管這些零件的工作表面都經(jīng)過(guò)精細(xì)的加工，但放大來(lái)看這些表面卻是凹凸不平的。

若不對(duì)這些表面進(jìn)行潤(rùn)滑，它們之間將發(fā)生強(qiáng)烈的摩擦。金屬表面之間的干摩擦不僅增加發(fā)動(dòng)機(jī)的功率消耗，加速零件工作表面的磨損，而且還可能由于摩擦產(chǎn)生的熱將零件工作表面燒損，致使發(fā)動(dòng)機(jī)無(wú)法運(yùn)轉(zhuǎn)。

Chapter3AUTOMOTIVELUBRICATIONSYSTEM潤(rùn)滑方式由于發(fā)動(dòng)機(jī)傳動(dòng)件的工作條件不盡相同，因此，對(duì)負(fù)荷及相對(duì)運(yùn)動(dòng)速度不同的傳動(dòng)件采用不同的潤(rùn)滑方式。1)壓力潤(rùn)滑壓力潤(rùn)滑是以一定的壓力把機(jī)油供入摩擦表面的潤(rùn)滑方式。這種方式主要用于主軸承、連桿軸承及凸輪軸承等負(fù)荷較大的摩擦表面的潤(rùn)滑。2)飛濺潤(rùn)滑利用發(fā)動(dòng)機(jī)工作時(shí)運(yùn)動(dòng)件濺潑起來(lái)的油滴或油霧潤(rùn)滑摩擦表面的潤(rùn)滑方式，稱飛濺潤(rùn)滑。該力式主要用來(lái)潤(rùn)滑負(fù)荷較輕的氣缸壁面和配氣機(jī)構(gòu)的凸輪、挺柱、氣門桿以及搖臂等零件的工作表面。3)潤(rùn)滑脂潤(rùn)滑通過(guò)潤(rùn)滑脂嘴定期加注潤(rùn)滑脂來(lái)潤(rùn)滑零什的工作表面，如水泵及發(fā)電機(jī)軸承等。

Chapter3AUTOMOTIVELUBRICATIONSYSTEM

NewWordsresidual

[r??z?d?u:?l]

adj.剩余的，殘留的varnish

[?vɑ:ni?]n.清漆，積碳buildupn.組合,集結(jié),累積,形成adhesion

[?d?hi:??n]n.粘著，附著，粘連cleanser

[?klenz?]n.清潔劑sludge[sl?d?]n.油泥grime

[gra?m]n.污垢，塵垢，煙灰clog[kl?ɡ]v.填塞，塞滿gum[ɡ?m]vt.粘合trough[tr?:f,tr?f]

n.槽，水槽，飼料槽，水盆，任何槽形物baffle[?b?fl]n.阻板，隔板sump[s?mp]

n.油底殼crankcase[?kr??kkeis]n.曲軸箱

NewWordsporosity[p?:?r?siti]n.多孔性,有孔性periphery[p??r?f?ri:]

n.外圍synthetic[sin?θetik]

adj.合成的，人造的，綜合的Additive[??ditiv]

n.添加劑；adj.添加的，附加的，加法的antiscuffn.磨損overhaul[???v??h?:l,???v??h?:l]vt.徹底檢查，大修neutralize[?nu:tr??la?z,?nju:-]

vt.使無(wú)效，抵消，使中和agitation[??d???te???n]n.激動(dòng)，興奮，煽動(dòng)，攪動(dòng)

PHRASESANDEXPRESSIONSstart-up起（啟）動(dòng)engineblock發(fā)動(dòng)機(jī)氣缸體dry-sump干油底殼wet-sump濕油底殼Chapter3AUTOMOTIVELUBRICATIONSYSTEM

PHRASESANDEXPRESSIONSpickuptube機(jī)油吸油管filterscreen濾網(wǎng)full-flowfilteringsystem全流式濾清器pressure-reliefvalve安全閥，泄壓閥bypassvalve旁通閥geartypeoilpump齒輪式機(jī)油泵，齒輪泵jockeypulley張緊輪，導(dǎo)向輪corrosioninhibitor阻蝕劑，腐蝕抑制劑detergent-dispersant清潔分散劑viscosityindex粘度指數(shù)foaminhibitor泡沫抑制劑Chapter3AUTOMOTIVELUBRICATIONSYSTEM

Reducingfrictiontominimizewearandlossofpoweristheprimaryjobalubricationsystemmustperform.Residualoilonenginepartsalsoprovideslubricationforenginestart-up.3.1LubricationPrinciples譯文：減小摩擦，降低磨損和動(dòng)力損失是潤(rùn)滑系統(tǒng)必須完成的主要工作。發(fā)動(dòng)機(jī)部件上的殘油也可為發(fā)動(dòng)機(jī)起動(dòng)提供潤(rùn)滑。Chapter3AUTOMOTIVELUBRICATIONSYSTEMTheengineoilformsasealbetweenthepistons,rings,andcylinders.Italsohelpstocoolen-gineparts.Withoutthecleaningactionofthelubricatingsystem,carbonandvarnishbuildupwouldbeexcessive.Theengineoilalsoabsorbstheshockanddampensthenoiseofmovingparts.譯文：發(fā)動(dòng)機(jī)機(jī)油在活塞、活塞環(huán)和氣缸間形成密封。它也有助于冷卻發(fā)動(dòng)機(jī)部件。如果沒(méi)有潤(rùn)滑系統(tǒng)的清潔作用，積碳會(huì)過(guò)量集結(jié)。機(jī)油還可減震和消弱（抑制）運(yùn)動(dòng)部件噪聲。Howsuccessfulthelubricationsystemisinperformingallthesefunctionsdependsonanumberoffactorsandconditions.Theremustbeanadequatesupplyofgood-qualitylubricantdeliveredtoallmovingenginepartsundersufficientpressuretoprovidehydrodynamiclubricationforrotatingpartsandoiladhesiontosurfacesubjecttoslidingfriction.譯文：潤(rùn)滑系統(tǒng)在執(zhí)行這些功能時(shí)的成功程度由許多因素和條件所決定。充足的優(yōu)質(zhì)潤(rùn)滑油在壓力作用下輸送到各運(yùn)動(dòng)發(fā)動(dòng)機(jī)部件，以此來(lái)為所有轉(zhuǎn)動(dòng)部件提供流體動(dòng)力潤(rùn)滑，機(jī)油附著在滑動(dòng)摩擦的部件表面。3.2.1oilpanTheoilpanboltsundertheengineblock,whereitsealsoffthebottomofengine.Shapedlikeatrough,thissheet-metalpanservesasthereservoirforabout5quartsofoil.Asoilflowsfromtheengine,itdrainsdownwardintotheoilpan.3.2PartsofthePressure-LubricationSystemes譯文：油底殼用螺栓固定在發(fā)動(dòng)機(jī)氣缸體下方，封閉發(fā)動(dòng)機(jī)的底部。它的形狀像一個(gè)溝槽，由薄鋼板制成，可儲(chǔ)存大約5夸脫的機(jī)油。當(dāng)機(jī)油從發(fā)動(dòng)機(jī)流出時(shí)，它將向下排入到油底殼中。Chapter3AUTOMOTIVELUBRICATIONSYSTEMTheoilpumpsucksoilfromthelowestpartoftheoilpan,theoilsump.Manyoilpanshavebaffles,whicharethinmetalpartitions.Thesekeeptheoilinthesumpwhenthecarcornershardorbrakessuddenly.Adrainplugatthebottomofthesumpallowsoiltobedrainedfromtheengine.Theoil-pangasketfitsbetweentheoilpanandthebottomoftheengineblock.譯文：油泵從油底殼的最低處抽油。許多油底殼帶有薄金屬隔板。它們可在汽車急轉(zhuǎn)彎或突然剎車時(shí)將機(jī)油保持在油底殼中。放油塞位于油底殼底部，可通過(guò)它將機(jī)油從發(fā)動(dòng)機(jī)排出。油底殼襯墊裝在油底殼和氣缸體底端之間。Inmostengines,theoilcirculatesintheengine,andthenreturnstothepan.Itstaysinthepanuntildrawnbackintotheenginebytheoilpump.Duringoperation,thesumpusuallyholds2to3quartsofoil.Therestoftheoilmovesthroughthepassagewaysofthelubricationsystem.譯文：在大多數(shù)發(fā)動(dòng)機(jī)上，機(jī)油在發(fā)動(dòng)機(jī)內(nèi)循環(huán)后要回到油底殼中。然后一直在那里存放，直到被油泵抽回到發(fā)動(dòng)機(jī)。在這個(gè)運(yùn)行過(guò)程中，油底殼只有2－3夸脫機(jī)油，其余的潤(rùn)滑系統(tǒng)通道內(nèi)流動(dòng)。Withtheengineoff,thepanholdsaboutfourquartsofoil.Thefifthquartisintheoilfilter.Becauseapoolofoilalwaysrestsinthesump,thetypeoflubricationsystemiscalledawet-sumpoilingsys-tem.譯文：發(fā)動(dòng)機(jī)熄火（停轉(zhuǎn)）時(shí)，油底殼有4夸脫機(jī)油，另外一夸脫的機(jī)油留在機(jī)油濾清器里。因?yàn)闄C(jī)油一直保持在油底殼中，所以這種類型的潤(rùn)滑系統(tǒng)也稱為濕式油底殼潤(rùn)滑系統(tǒng)。Adry-sumpoilsystemisusedinmanyracingengines.Thissystemhasaseparatestoragetankfortheoil.Asecondoilpumpdrawsoilfromtheoilpanassoonastheoildrainsfromtheengine.Asaresult,adry-sumpsystemcancirculatemoreoilthroughtheenginethanawet-sumpsystem.譯文：干式油底殼潤(rùn)滑系統(tǒng)在許多賽車發(fā)動(dòng)機(jī)中采用。這個(gè)系統(tǒng)有單獨(dú)的存儲(chǔ)油箱。只要機(jī)油從發(fā)動(dòng)機(jī)排出，就立即被第二個(gè)油泵從油底殼中抽出。因此，干式油底殼系統(tǒng)要比濕式油底殼系統(tǒng)在發(fā)動(dòng)機(jī)循環(huán)更多的機(jī)油。3.2.2OilPumpInmostcars,theoilpumpisinthecrankcaseabovethesump.Itdrawsoilthroughatubethatextendsdownwardintothesump.Thistube,calledtheoil-pumppickuptube,hasafilterscreenoveritsbottomend.Thescreenkeepslargepiecesofsludgeanddirtfrombeingdrawnintothepump.譯文：在多數(shù)汽車上，油泵位于油底殼上方的曲軸箱中。它通過(guò)延伸到油底殼中的油管把機(jī)油抽出。這個(gè)管稱為油泵吸油管，在它的底端帶有一個(gè)濾網(wǎng)。濾網(wǎng)可防止將大塊的油泥和污垢抽到油泵中。Thetubemaybehingedonthepumpendsothatitcanmoveupanddownastheoillevelchangesinthesump.Thus,thepumpalwaysdrawsoilfromthetopofthesump,notfromthebot-tomwherethedirtandsludgetendtosettle.Moderncarsuseoneoftwocommontypesofoilpumps—thegear-typeandrotor-type.譯文：吸油管用鉸鏈接合在油泵末端，以便它能夠隨油底殼內(nèi)的油面變化而上下浮動(dòng)。因此，油泵是從油底殼上面抽油，而不是從其底部油泥和污垢沉積的地方抽油。油泵有兩種類型，齒輪式和轉(zhuǎn)子式?，F(xiàn)代汽車一般可采用其中的一種。3.2.3OilFiltersAmodernengineusesafull-flowfilteringsystem(Figure3-1).Inthissystem,theoutputoftheoilpumpflowsthroughtheoilfilterbeforemovingthroughtheengine.Inotherwords,theoilisfilteredandcleanedbeforeeachtripthroughtheengine.譯文：現(xiàn)代汽車采用全流式過(guò)濾系統(tǒng)。在這個(gè)系統(tǒng)中，油泵輸出機(jī)油要先流過(guò)機(jī)油濾清器，然后才穿過(guò)發(fā)動(dòng)機(jī)。換句話說(shuō)，機(jī)油在到達(dá)發(fā)動(dòng)機(jī)各處之前被過(guò)濾和凈化。Whenanenginerunsat3,000rpm,itsentirefivequartsofoilpassthroughthefilteratleastonceeveryminute.Thustheoilfilterensuresthatonlycleanoilenterstheengine.譯文：當(dāng)發(fā)動(dòng)機(jī)轉(zhuǎn)速在3000rpm時(shí)，5夸脫機(jī)油每分鐘至少穿過(guò)濾清器一次。因而機(jī)油濾清器可確保只有潔凈的機(jī)油才能進(jìn)入發(fā)動(dòng)機(jī)。Modernenginesusereplaceableoilfilters.Whendirty,suchascrew-onfilterisreplacedwithanewone.Insidethesteeloutercasingoftheunit,aspecialpaperactsasafilter.Foldedandtightlypacked,thispaperhasjusttherightporosity.Thesetinyholesinthepaperallowoiltopassthrough,butfilteroutdirtandsludge.Thepaperistreatedtoprotectitfromacidorwaterintheoil.譯文：現(xiàn)代發(fā)動(dòng)機(jī)使用可更換的機(jī)油濾清器。當(dāng)它布滿污垢時(shí)，這種螺紋連接濾清器就可被換成新的。在濾清器的鐵外殼內(nèi)有一層特殊的紙作為濾芯。這種紙?jiān)诒徽郫B和緊密壓縮后，就具有了多孔性。紙上的這些小孔能夠?yàn)V除機(jī)油中的油泥和污垢。這種紙經(jīng)過(guò)（酚醛樹脂）處理后，在油中具有抗酸性和抗水濕性。Normally,oilenterstheoilfilterfromtheoutside.Oilentersthefilteraroundtheouteredgeofthebase.Theoilflowsthroughthepapertothecenterofthecontainer.Itthenflowsouttotheen-gine.Mostfiltersalsohaveapressure-reliefvalve,orbypassvalve.Suchavalveallowsoiltoflowtotheenginewithoutgoingthroughthefilter.譯文：通常，機(jī)油是從外面進(jìn)入機(jī)油濾清器。繞底座外圍進(jìn)入濾清器。機(jī)油流過(guò)紙濾芯到達(dá)容器中心，然后流出到發(fā)動(dòng)機(jī)。大部分濾清器還帶有一個(gè)卸壓閥，或稱為旁通閥。它可使機(jī)油直接流到發(fā)動(dòng)機(jī)而不需要穿過(guò)濾清器。Thisisnecessarywhenthefilterbecomestoocloggedforoiltopassthroughit.Thus,apluggedfilterallowsdirtyoiltocirculatethroughtheengine.Topreventthis,theoilandoilfiltershouldbechangedregularity.譯文：這在濾清器被嚴(yán)重堵塞，機(jī)油不能通過(guò)濾芯時(shí)是十分必要的。因而，被堵塞的濾清器會(huì)造成污油在發(fā)動(dòng)機(jī)內(nèi)循環(huán)。為了避免出現(xiàn)這種情況，機(jī)油和機(jī)油濾清器應(yīng)該定期更換。Aninternalcombustionenginewouldnotrunforevenafewminutesifthemovingpartswereallowedtomakemetal-to-metalcontact.Theheatgeneratedduetothetremendousamountsoffric-tionwouldmeltthemetals,leadingtothedestructionoftheengine.3.3EngineLubrication譯文：如果允許運(yùn)動(dòng)部件之間金屬接觸，內(nèi)燃機(jī)運(yùn)行不了幾分鐘。大量摩擦產(chǎn)生的熱量會(huì)把金屬熔化，導(dǎo)致發(fā)動(dòng)機(jī)的損壞。Chapter3AUTOMOTIVELUBRICATIONSYSTEMTopreventthis,allmovingpartsrideonathinfilmofoilthatispumpedbetweenallthemovingpartsoftheengine.Oncebe-tweenthemovingparts,theoilservestwopurposes.Onepurposeistolubricatethebearingsur-faces.譯文：為防止這樣，所有運(yùn)動(dòng)部件浮在一層薄油膜上，這層油在發(fā)動(dòng)機(jī)各個(gè)運(yùn)動(dòng)部件之間傳送。運(yùn)動(dòng)部件之間的機(jī)油有兩個(gè)作用，一是潤(rùn)滑軸承面Theotherpurposeistocoolthebearingsbyabsorbingthefriction-generatedheat.Theflowofoiltothemovingpartsisaccomplishedbytheengine'sinternallubricatingsystem.Figure3-2showsaengine'slubeoilcircuitschematic.譯文：另一個(gè)是通過(guò)吸收摩擦產(chǎn)生的熱量來(lái)冷卻軸承。（到達(dá)運(yùn)動(dòng)部件的）機(jī)油流動(dòng)是由發(fā)動(dòng)機(jī)的內(nèi)部潤(rùn)滑系統(tǒng)來(lái)實(shí)現(xiàn)的。圖3－2是發(fā)動(dòng)機(jī)的潤(rùn)滑油路簡(jiǎn)圖。Theoilpumpisofthegeartype,consistingessentiallyoftwogearsinmeshandrequiresnoat-tentionoradjustment.Itishousedinthesump,beingdrivenbyashaftandskewgearingfromthecamshaft.譯文：齒輪式油泵主要由兩個(gè)嚙合齒輪構(gòu)成，不需要保養(yǎng)或調(diào)整。它放在油底殼中，由軸和凸輪軸的斜齒輪驅(qū)動(dòng)。Oilfromthesumpisdeliveredatfullpressuretoallmainbearingsandcamshaftbearingsthroughgallerypipesanddrillingsinthecylinderblock.Thebig-endbearingsarefedfromthemainbearingsviapassagesinthecrankshaft.譯文：油底殼機(jī)油通過(guò)氣缸體中的油道和鉆孔全壓傳送到所有（曲軸）主軸承和凸輪軸軸承。（連桿）大端軸承潤(rùn)滑油由主軸承通過(guò)曲軸中的油道提供。Lubricationforthetimingchainissuppliedattwopoints;byafeedfromthefrontcamshaftbearingintotheperipheryofthecamshaftchainwheelandalsobyoilfedthroughthehollowshaftonwhichthetimingchainjockeypulleyismountedaridthencethroughholesinthecircumferenceofthejockeypulley.譯文：正時(shí)鏈條的潤(rùn)滑由兩路供給，一是從前凸輪軸軸承到其鏈輪外圍。另一路是先通過(guò)正時(shí)鏈條導(dǎo)輪的空心軸，然后再通過(guò)導(dǎo)向輪輪周上的孔。Theinlet(upper)andexhaust(lower)rockershaftsarehollow,theinletshaftbeingfedwithoilfromtherearendofthemaingallerypipeviaanexternalpipeline,whilstthatfortheexhaustrockersandinletfollowersissuppliedviadrillingsfromthecentercamshaftbearings.譯文：進(jìn)氣和排氣搖臂軸是空心的，進(jìn)氣軸由主軸承潤(rùn)滑油管后端通過(guò)一個(gè)外部管道供油，而排氣軸和進(jìn)氣軸從動(dòng)件潤(rùn)滑油通過(guò)中心凸輪軸軸承鉆孔提供。Eachrockerandfollowerreceivesitsoilthroughsmallholesdrilledintherockershaftsandinturntheyarethem-selvesalsodrilled,sothattheoilfindsitswaythroughthemandthenceoutagaintolubricatethepointsofcontactwiththevalves,push-rodsandcamshaft.Thedistributordriveshaftislubricatedwithoilfedfromtheexhaustrockershaftviaahollowbolt.譯文：每個(gè)搖臂和挺桿從搖臂軸上所鉆的小孔得到潤(rùn)滑油，然后機(jī)油進(jìn)入它們本身帶有的孔道，從這些孔道出來(lái)后，再去潤(rùn)滑與之相連的氣門、推桿和凸輪軸。分電器傳動(dòng)軸由排氣搖臂軸通過(guò)一個(gè)空心螺栓供油。Surplusoilfromtheinletvalvegearreturnsthroughthecylindercastingandthatfromtheex-haustvalvegeardirecttothesump.譯文：來(lái)自進(jìn)氣門配氣機(jī)構(gòu)的殘油通過(guò)氣缸體回流，而排氣門配氣機(jī)構(gòu)殘油則直接落到油底殼中。Motoroilsforautomobileenginesfallintotwobasiccategories:petroleum-basedoilsandsyntheticoils.Petroleum-basedoils,however,containavarietyofadditives;soinfactthey,too,arepartlysynthetic.Someofthemajoradditivesincludethosedescribedhere.3.4LubricationOils譯文：汽車發(fā)動(dòng)機(jī)潤(rùn)滑油有兩種類型：從石油中提煉出的潤(rùn)滑油和合成潤(rùn)滑油。從石油中提煉出的潤(rùn)滑油含有多種添加劑，因此，實(shí)際上也是部分合成的。其主要的添加劑包括以下幾點(diǎn)：Chapter3AUTOMOTIVELUBRICATIONSYSTEMCorrosioninhibitorsreducetheformationofharmfulacidsbyattackingtheacid-formingingredi-ents.Combustionproducesanumberofby-products,includingacidsandwater.Corrosioninhibitorsneutralizethesecombustionby-productsbeforetheycandoanyharmtotheengine.Acoldengine,richfuelmixtures,apoorlytunedengine;andmuchshorttrip,cold-weatherdrivingincreasestheamountofacidsproduced.譯文：防腐劑可通過(guò)破壞酸性成分來(lái)減少有害酸性物質(zhì)的形成。燃燒會(huì)產(chǎn)生大量的副產(chǎn)品，包括酸和水。防腐劑可在它們損害發(fā)動(dòng)機(jī)之前中和這些副產(chǎn)品。在冷機(jī)、濃可燃混合氣、調(diào)試不好的發(fā)動(dòng)機(jī)以及短程、寒冷的天氣下運(yùn)轉(zhuǎn)都會(huì)增加酸性物質(zhì)。Antiscuffadditiveshelptopolishmovingparts,includingcams,pistons,andcylinderwalls.Thisisparticularlyimportantduringnewenginebreak-inandafteranengineoverhaul.Sinceheatistheprimeenemyofantiscuffadditives,operatingconditionsthatproduceexcessivelyhighenginetemperaturesreducethelifeexpectancyoftheseadditives.Thistypeofoperationrequiresmorefre-quentoilchangesthandoesnormaloperation.譯文：防擦傷（拋光）添加劑有助于拋光（磨光）運(yùn)動(dòng)部件，如：凸輪，活塞和氣缸壁。這在新發(fā)動(dòng)機(jī)磨合期間或發(fā)動(dòng)機(jī)大修后是非常重要的。因?yàn)闊崃渴菕伖馓砑觿┑淖畲笪：?，所以發(fā)動(dòng)機(jī)高溫運(yùn)行時(shí)會(huì)減小這些添加劑的預(yù)期壽命。高溫條件下比正常工作，潤(rùn)滑油更換要更頻繁一些。Detergent-dispersantscleanenginepartsduringoperationandkeepthesecontaminantsinsus-pensionintheoil.Astheoilisforcethroughthefilter,themajorityofthesecontaminantsaretrappedbythefilter.譯文：清潔分散劑可在發(fā)動(dòng)機(jī)工作時(shí)，清潔發(fā)動(dòng)機(jī)部件，并使那些污染物懸浮在機(jī)油中。當(dāng)機(jī)油通過(guò)濾清器時(shí)，大部分污染物就可被濾清器過(guò)濾掉。Viscosityindeximproverstendtostabilizeorimprovetheviscosityofengineoilsatvarioustem-peratures.Theytendtogivetheoilmorebodywhentheoiliscold.Inotherwords,theyimprovethebodyandfluidityoftheoil.Theabilityoftheoiltocarryaloadathightemperatureisimprovedbythisadditive,andtheabilityoftheoiltoflowwhencoldisalsoimproved.譯文：粘度指數(shù)提高劑可穩(wěn)定或提高發(fā)動(dòng)機(jī)機(jī)油在各種溫度條件下的粘度。在機(jī)油溫度低時(shí)，會(huì)增加機(jī)油的濃度。換句話說(shuō)，它可提高機(jī)油的粘度和流動(dòng)性。這種添加劑可提高機(jī)油在高溫時(shí)攜帶負(fù)載的能力以及在低溫時(shí)的流動(dòng)性。Foaminhibitorsreducethetendencyofoiltofoam.Heatandagitationmixtheoilwithairtocreatefoam.Oilfoamreducesthelubricatingabilityoftheoilandcausesoilstarvationandfailureofengineparts.Lossofoilpressureduetofoamingincreasesthisproblem.譯文：泡沫抑制劑可減小機(jī)油起泡沫。把機(jī)油和空氣混合在一起熱攪拌會(huì)產(chǎn)生泡沫。機(jī)油泡沫會(huì)降低機(jī)油的潤(rùn)滑能力，并造成缺油和發(fā)動(dòng)機(jī)部件損壞。由于起泡所引起的油壓降低會(huì)使這種情況增多。I.Answerthefollowingquestions:1.Whatisthepurposeofautomobilelubricationsystem?Reducingfrictiontominimizewearandlossofpower.2.Howdoesinternalengineleakageaffectoilpressure?3.Explainwhatthefunctionofoilis.Theengineoilformsasealbetweenthepistons,rings,andcylinders.Italsohelpstocoolen-gineparts.Withoutthecleaningactionofthelubricatingsystem,carbonandvarnishbuildupwouldbeexcessive.Theengineoilalsoabsorbstheshockanddampensthenoiseofmovingparts.4．Nameatleastthreecommonadditivesusedincompoundin