Airconditioning1教學(xué)提綱

1、Good is good, but better carries it.精益求精，善益求善。Airconditioning1-Airconditiong汽車空調(diào)窗體底端TherefrigerantcycleThisisthefirstinaseriesofarticlestogivethetechnicianaclearunderstandingoftheautomotiveA/Csystem.汽車空調(diào)制冷循環(huán)這是本系列文章的第一篇。此系列旨在讓技術(shù)人員們對(duì)于汽車空調(diào)系統(tǒng)（簡(jiǎn)稱汽車A/C系統(tǒng)）有一個(gè)清晰的認(rèn)識(shí)。Here,welookattherefrigerantcycle,andthebas

2、icprinciplesassociatedwiththeheattransferaroundthethermalexpansionvalvetype.在此，我們將介紹一下制冷循環(huán)系統(tǒng)，和一些與熱力膨脹閥式制冷系統(tǒng)類型的熱轉(zhuǎn)移相關(guān)的基本原則。A/Csystem.TwopointsthatarecriticaltotheunderstandingoftheA/Csystemaretheroutethroughwhichtherefrigerantflowsandthedifferingstatestherefrigerantisinasittravelsaroundthecircuit.A/C系

3、統(tǒng)有兩點(diǎn)對(duì)于理了解解A/C系統(tǒng)的運(yùn)行非常關(guān)鍵，即制冷劑流動(dòng)的線路和制冷劑在環(huán)路中循環(huán)時(shí)的不同狀態(tài)。Agreatstartingpointfortheunderstandingofthisisatthecompressor.科技類英語(yǔ)翻譯論文了解這些的一個(gè)很好的最好切入點(diǎn)就是壓縮機(jī)。Commonly,A/Ccompressorscontainreciprocatingpistons.通常A/C壓縮機(jī)都包含一些往復(fù)式活塞壓縮機(jī)都有一些往復(fù)式活塞。Asthepistontravelsinonedirection,throughaonewayvalve,itdrawsintherefrigerantg

4、asfromthelowpressuresideofthecircuit.活塞向一個(gè)方向移動(dòng)時(shí)，環(huán)路中低壓端的氣態(tài)制冷劑通過(guò)一個(gè)單向閥，循環(huán)中低壓端的氣態(tài)制冷劑被吸入進(jìn)來(lái)。Thepistonthentravelsbackintheotherdirectionandcompressestherefrigerantgascausingalargeincreaseinpressure.活塞然后向反方向移動(dòng)，壓縮氣態(tài)制冷劑，引起壓強(qiáng)急劇升高。Oncethepressurereachesaspecificthresholditwillovercomeasecondonewayvalveandallowt

5、henowhighpressurerefrigerantgastoexitthecompressorandintothehighpressuresideoftherefrigerantcircuit.一旦壓強(qiáng)達(dá)到臨界點(diǎn)，它將迫使第二個(gè)單向閥打開(kāi)，此時(shí)高氣壓中的氣態(tài)制冷劑從壓縮機(jī)中被釋放出來(lái)，進(jìn)入制冷循環(huán)的高壓端進(jìn)入制冷環(huán)路的高壓端。Thereisarelationshipbetweenpressureandtemperature.這里就存在著一個(gè)壓強(qiáng)與溫度的關(guān)系Whenthepressureofasubstanceisincreaseditstemperaturewillalsoincreas

6、e.當(dāng)物體所受的壓強(qiáng)升高，它的溫度將隨之升高。Thepressureincreasessubstantiallyastherefrigeranttravelsthroughthecompressor.制冷劑通過(guò)壓縮機(jī)時(shí)，壓強(qiáng)急劇升高。Thelowpressuresideofthecircuitwouldtypicallybeunderthepressureof2bar;thehighpressurewouldtypicallybeunderthepressureof15bar.循環(huán)環(huán)路中的低壓端正常壓強(qiáng)為2巴，高壓端的正常壓強(qiáng)為15巴。Ariseof13bar!一下增加了13巴！Thislar

7、geincreaseinpressurealsoresultsinalargeincreaseintemperature.這一壓強(qiáng)的劇增同樣引起了溫度的驟升這一壓強(qiáng)的劇增同樣引起了溫度的大幅上升Thetemperatureoftherefrigerantenteringthecompressorwouldbe10-20Candthetemperatureoftherefrigerantexitingthecompressorwouldbeintheregionof90C!制冷劑進(jìn)入壓縮機(jī)時(shí)溫度大概為10-20C，離開(kāi)時(shí)溫度則會(huì)變?yōu)?0C左右！Thishighpressurehightemper

8、aturegasthentravelsonwardstothecondenseralargeheatexchangerusuallylocatedinfrontoftheengineradiator.！這一高壓高溫氣體接著向冷凝器轉(zhuǎn)移。冷凝器是一個(gè)大的換熱器，通常位于引擎散熱器的前端。Iftwosubstancesofdifferingtemperaturesareplacedtogether,heatwilltravelfromthehottersubstancetothecoolersubstanceuntilbothsubstancesreachanequaltemperature.如果

9、不同溫度的兩種物質(zhì)被放置在一起，熱量將會(huì)從較熱的物體向較冷的物體轉(zhuǎn)移，直到兩者溫度相等相當(dāng)。Asthetermheatexchangersuggests,heatisexchangedfromthehotterbodytothecoolerbody.正如換熱器其名，熱量從較熱物體轉(zhuǎn)移交換到較冷物體上。Inthiscasethehotterbodyistherefrigerantgasandthecoolerbodycomprisesthefinsofthecondenser.這一情況中，較熱物體是氣態(tài)制冷劑，較冷物體包括冷凝器的那些散熱片。Astheheatistransferredtothe

10、finsofthecondenser,coolingairflowsoverthem.當(dāng)熱量被轉(zhuǎn)移到散熱片上時(shí)，冷空氣從上層經(jīng)過(guò)。Againaheatexchangeprocessoccursallowingtheheatfromthefinstotransferintothecoolerairtravellingpasttheminto,usually,theenginecompartment.這樣，又一次熱交換過(guò)程發(fā)生，散熱片上的熱量轉(zhuǎn)移至上空經(jīng)過(guò)的冷空氣中，這些冷空氣通常是去往引擎室的。Astheheatisremovedfromtherefrigerantitstartstoconde

11、nse.由于制冷劑中的熱量被去除當(dāng)熱量從制冷劑中剔除，制冷劑開(kāi)始液化。當(dāng)制冷劑繼續(xù)穿過(guò)冷凝器時(shí)，它不斷液化Astherefrigerantcontinuesitsjourneythroughthecondenseritcontinuestocondenseand,ideally,therefrigerantwillturnfullyintoaliquidbythetimeitexitsthecondenser.理想狀態(tài)下正常情況下，當(dāng)制冷劑離開(kāi)冷凝器時(shí)，它會(huì)完全轉(zhuǎn)變?yōu)橐簯B(tài)。Fromthecondenser,theliquidrefrigeranttravelsontothemodulator.

12、液態(tài)冷凝劑接著從冷凝器向調(diào)節(jié)器移動(dòng)。Thislookslikeanextratubeweldedontothesideofthecondenser.調(diào)節(jié)器看起來(lái)像是焊接到冷凝器一端的條附加管道。Themodulatorperformsthreemainactions.One,itactsasafilter,filteringoutparticlesastheytravelaroundtheACsystem.它主要有三個(gè)功能：首先，它像是一個(gè)過(guò)濾器，顆粒在穿過(guò)AC系統(tǒng)時(shí)會(huì)被過(guò)濾出來(lái)。Second,itactsasadryer.第二個(gè)作用是，它像一個(gè)干燥器。Thedryerinthemodulat

13、orcontainsdesiccant(likethesilicagelyoufindinanewboxofshoes).調(diào)節(jié)器里的干燥器裝著干燥劑，貌似新鞋鞋盒中的硅膠。Thisdesiccantabsorbswater.Aswatergetsintothesystemthedryertriestoremoveit.干燥劑會(huì)吸收水分，所以當(dāng)水分穿過(guò)系統(tǒng)時(shí)，干燥劑會(huì)將水分吸收掉。Thethirdfunctionofthemodulatorisareservoir.調(diào)節(jié)器的第三個(gè)功能是一個(gè)儲(chǔ)存器裝置。Bearinginmindthepressureandtemperatureoftherefri

14、gerantinsidetheACsystemregularlychanges,sodoestherefrigerantsvolume.AC系統(tǒng)中循環(huán)的制冷劑的壓強(qiáng)和溫在度是有規(guī)律變化的，制冷劑的劑量也是如此。Thisvaryingvolumeisaccommodatedbythereceiverdryer.變化的劑量?jī)?chǔ)存在接受者角色的干燥劑儲(chǔ)液干燥器中。Fromthemodulator,therefrigerantflowstowardsthethermalexpansionvalve.制冷劑從調(diào)節(jié)器中出來(lái)，流向熱膨脹閥。Thisisaselfregulatingvalvewhichcont

15、rolstheamountofrefrigerantabletopassintoanotherheatexchangerlocatedbytheheatermatrixcalledtheevaporator.這個(gè)閥是一個(gè)自動(dòng)調(diào)節(jié)閥，控制可以通過(guò)的制冷劑劑量。Asliquidrefrigerantpassesthroughtheexpansionvalve,intothelowpressuresideofthecircuit,apressurereductionoccurs.Thispressurereductioncausestheliquidrefrigeranttobeontheverge

16、ofbecomingagasbutitisstillaliquidatthisspecificpoint.制冷劑通過(guò)后將流入另一個(gè)換熱器。這是由稱為蒸發(fā)器的加熱器矩陣所固定的一個(gè)換熱器。液態(tài)制冷劑通過(guò)膨脹閥，進(jìn)入環(huán)路的低壓端時(shí)，壓強(qiáng)減小。壓強(qiáng)的減小使得液態(tài)制冷劑幾乎變成氣態(tài)，但在通過(guò)膨脹閥這一刻，它的狀態(tài)仍是液態(tài)。Ifyouincreasethepressureappliedtoagasyoueventuallyendupwithaliquid;如果你增大施加在氣體上的壓強(qiáng)，最終它會(huì)變成液態(tài)。inversely,ifyoureducethepressureappliedtoaliquidyou

17、willeventuallyendupwithagas.反過(guò)來(lái)，如果減小施加在液體上的壓強(qiáng)，它會(huì)變成氣態(tài)。Itisonlywhentheliquidtravelsintotheevaporatorthattheliquidevaporatesandbecomesagas.只有在液態(tài)制冷劑穿過(guò)蒸發(fā)器時(shí)，液體蒸發(fā)，變成氣態(tài)。Thisprocessoccursduetotherefrigerantabsorbingheatfromtheairbeingblownthroughtheevaporator.發(fā)生這一過(guò)程的原因是制冷劑從經(jīng)過(guò)蒸發(fā)器的空氣中吸收了熱量。Theprocessofevaporat

18、ioncausesacoolingeffect.蒸發(fā)的過(guò)程產(chǎn)生了制冷效應(yīng)。Thelargerthequantityofliquidtravellingintotheevaporator,themoreevaporationthatwilloccur,whichinturnwillleadtoahigherquantityofheatenergybeingabsorbedbytheprocess.經(jīng)過(guò)蒸發(fā)器的液體量越多，就會(huì)發(fā)生越多的蒸發(fā)過(guò)程。其結(jié)果就是在這一蒸發(fā)過(guò)程中，被吸收的熱量也就越多。Asairisblownthroughthefinsoftheevaporator(andasstate

19、deviouslyhottravelstocold),theheatcarriedbytheairtransferstothecoldfinsandinturnisabsorbedbytherefrigerant.空氣被吹動(dòng)經(jīng)過(guò)蒸發(fā)器的散熱片空氣被鼓吹經(jīng)過(guò)蒸發(fā)器的散熱片，（如前所說(shuō)，是熱流向冷），空氣負(fù)載的熱量轉(zhuǎn)移到冷的散熱片上，反過(guò)來(lái)被制冷劑吸收。Astheairlosessomeofitsheat,theairthatcomesbackoutofthefinsoftheevaporatoriscoolandthatcooledairisthenventedintothepassengerc

20、ompartment.當(dāng)空氣失去一定熱量時(shí)，蒸發(fā)器散熱片中出來(lái)的回流空氣是冷空氣，這股冷空氣接著會(huì)被排放到乘客區(qū)這股冷空氣接著會(huì)被釋放到乘客區(qū)。Nowthattherefrigeranthasabsorbedsomeoftheheatfromthepassengercompartment,ithasdoneitsjobintheevaporatorandoutittravelsoftheevaporatorinagaseousstate.制冷劑此時(shí)已經(jīng)吸收了來(lái)自乘客區(qū)的一部分熱量，這意味著它在蒸發(fā)器中的任務(wù)已經(jīng)完成。離開(kāi)蒸發(fā)器后，它的狀態(tài)為時(shí)氣態(tài)。Therefrigeranttravelsbacktothecompressorleavingthelowpressuresideofthecircuitandthewholeprocessstartsagain.制冷劑重新回到壓縮機(jī)，然后離開(kāi)循環(huán)的低壓端然后離開(kāi)環(huán)路的低壓端，整個(gè)過(guò)程重新開(kāi)始。Coolertemperaturesmeansthattwod