附錄SRSAirbagAirbagareknownasSupplementalRestraintSystem（SRS）andhasbecomemorecommoninmoderncars.Thebagitselfismadeofathin,nylonfabric,whichisfoldedintothesteeringwheelordashboardor,morerecently,theseatordoor.Ifairbagsarefitted,thesteeringwheelcoveranddashboardcoverwillusuallyhavethewords"airbag"or"SRSairbag"stampedintothem.Thesensorsdetectimpactandsignaltheairbagtoinflate.Atleasttwosensorsmustbeactivatedfortheairbagtoinflate.Thereareusuallyfivesensors:twoattheradiatorsupport,oneattheright-handfenderapron,oneattheleft-handfenderapron,andoneatthecowlinthepassagecompartment(Afewsystemuseonlysensors—oneinfrontoftheradiatorandantherinthepassengercompartment).Thereisaninterlockbetweenthesensors,sothattwoormoremustworktogethertotriggerthesystem.Theairbagsystemsaredesignedtodeployincaseoffrontalcollisionsonly.TheSRSairbaginflatorcontainsasolidchemicalgasgenerator.ThesolidchemicalsaresafelystoredinametalchamberinsidetheSRSairbagmodule.Eachinflatorissealedtokeepoutmoisture.SRSairbagaredesignedtodeployinmoderatetomajorcrashesonlyandshouldnotdeployinminorcrashes.ThefollowingfourstepsshowhowtheSRSairbagworks:Inanimpact,sensorsinthecardetectthesuddendeceleration.Ifthecrashidsevereenough,electricityflowstotheinflatorandcausesignitionofthegasgenerator.Thegasgeneratorthenrapidlyburnsinthemetalchamber.Therapidburningproducesinertgasesandamountsofdust.Theinsertgasesanddustarecooledandfilteredduringinflationoftheairbag.Theinflatingairbagsplitsopenthetrimcover.Theairbagthenrapidlyunfoldsandinflatesinfrontoftheoccupant.Afterinflation,thegasisventedthroughopeningsoropenweaveareasintheairbag.Thesestepstakeplaceinafractionofasecond.Airbagsdeflateinunderasecondandmaybepushedasideforoccupantstoexit.SeeFig.10-1Thereisageneralmisconceptionthatairbagsprovideasoftcushionandwillpreventbruisingorotherminorinjuriesinlowseveritycrashes—thisisincorrect.SRSairbagsaredesignedtoreducepeakloadsontheheadchestinseverecrashes(thosewheredeathorlongtermbraininjuryarepossible).Whendeploying,theairbagisfirm,butitabsorbsenergyasthegasesarereleasedthroughthevents.Whileairbagssignificantlyreducetheriskofseriousorfatalinjuryincrashes,therearesomerisksfromthedevelopmentofairbagsinlowspeedcrashes.Forthisreasonmoderncarsusearangeofintelligentsensingfunctionstoensurethatacrashisreallyhappening(notjustabumpintheroadoraminorknockinthecarpark)andtofireairbagsatthebesttime.Thisreducesthelikelihoodofairbagsdeployinginminorcrashes.ThenewSRSairbagsystemusesaword-firstdualinflator,two-stagedeploymentsystemforfrontpassengers.Thesystemhastwoseparateinflatorsthatcanbeactivatedseparatelyortogether,dependingonthevehiclespeedandotherfactors,suchaswhetherthepassengeriswearingaseatbelt.Inrelativelylow-speedimpacts,theinflatorsareactivatedoneaftertheotherforslowerinflation.Athigherspeeds,bothinflatorsareactivatedsimultaneouslyforquick,effectiveprotection.Thesystemdetectsifseatbeltsarebeingworn,adjustingtheairbaginflationthresholdspeedformaximumeffectsandminimumrisk.ThisSRSairbagalsocontrolstheseatbeltpretensioners,switchingthemoffinlow-speedaccidentstopreventunnecessaryrisktovulnerablepassengers,suchastheelderly.Apassenger-sensingdevicecontrolsideairbagdevelopmenttopreventpotentialinjuriesfromthesefast-activatingsystems.Sixsensorsarebuiltintothefrontpassengerseat.Onedetectsthesizeofthepassenger,andanotherdetermineswhetherthepassenger’sheadisinthedevelopmentpathoftheairbag.Ifthesensorsdetectachildasleepwithhis/herheadlearningtooneside,thesideairbagisdeactivatedtopreventheadorneckinjuriesfromairbagdeployment.ForevensaferSRSairbagcontrol,asophisticatedthree-pointsensingdevicehasbeendevelopedtodeterminethestrength,directionandtypeofimpact.Thesystemhasacentralsensorandtwosatellitesensorsoneachsideofthevehicle.Thissystemisparticularlysuitedtodistinguishingbetweentheimpactofatirehittingakerbandastrongimpact.Ittriggersonlytheappropriateairbagorairbags.Inthefuture,wewillfurtherexpandthenumberofvehiclesequippedwith6airbagsbyaddingsideairbagsthatprotectthearmandchestareasandcurtainairbagsthatprotecttheheadareainsideimpacts.SeeFig.10-2Fig.10-2Six-airbagposition1/4Curtainairbagsystem2/5Sideairbagsystem3Passengerairbagsystem6DriverairbagsystemSRS安全氣囊

安全氣囊被稱為輔助約束系統(tǒng)，現(xiàn)代的汽車已成為較為普遍使用。這個包本身是由一個薄和尼龍布做成，折疊于方向盤或儀表板，或者更近，還有座椅或車門之間。如果裝有安全氣囊，方向盤套和儀表板蓋將通常會包含單詞”安全氣囊"或”SRS氣囊”加蓋到他們。

該傳感器檢測信號的影響下，安全氣囊充氣。至少有兩個傳感器必須被激活，安全氣囊才會充氣。通常有五個傳感器：兩個散熱器下，一個在右側(cè)擋泥板圍裙，一個在左邊的擋泥板圍裙，同時在車廂通道罩（少數(shù)系統(tǒng)只使用兩個傳感器——一個在散熱器的前面和另一個在乘客室里面）。傳感器之間有一個聯(lián)鎖，使兩個或兩個以上必須共同作用下才會觸發(fā)系統(tǒng)。安全氣囊系統(tǒng)的設(shè)計只部署在正面碰撞情況。

在SRS安全氣囊充氣機包含了堅實的化學(xué)氣體發(fā)生器。固體化學(xué)品的安全儲存在SRS安全氣囊模塊金屬腔里面。每個充氣都是密封的，防止有水分進入。SRS安全氣囊為了只部署在中度至大崩潰，而不應(yīng)部署在輕微的崩潰。

以下四個步驟說明如何在SRS安全氣囊工作原理：

1。在碰撞，在汽車傳感器檢測突然減速。如果崩潰ID嚴重不足，電力流向，造成充氣的氣體發(fā)生器點火。

2。氣體發(fā)生器然后迅速在金屬腔燃燒，快速燃燒產(chǎn)生的惰性氣體和粉塵量。充入的氣體和塵埃在安全氣囊的膨脹過程中冷卻和篩選。

3。安全氣囊的膨脹裂開的裝飾蓋。安全氣囊然后迅速展開，并在乘客面前膨脹。4。膨脹后，氣體通過通風(fēng)口或在安全氣囊打開編織領(lǐng)域排出。采取這些步驟要在幾分之一秒內(nèi)。安全氣囊放氣在一秒鐘之內(nèi)就應(yīng)該被推開，乘客就逃出來。如圖10-1（安全氣囊是如何工作的）注：Crashsensor碰撞傳感器；Inflator氣體發(fā)生器；Airbag安全氣囊；Nitrogergas氮氣

有一個普遍的誤解，安全氣囊提供軟墊，和將防止傷痕或其他低嚴重車禍中的受輕傷，這是不正確。SRS安全氣囊為了減少對嚴重崩潰中的頭胸的峰值負載（這些死亡或長期在腦損傷有可能）。當部署，安全氣囊是堅固的，但它吸收能量的氣體通過通風(fēng)口釋放。

雖然安全氣囊在撞車顯著減少嚴重或致命傷害的危險，還有來自于低速碰撞安全氣囊的發(fā)展中的一些風(fēng)險。由于這個原因，現(xiàn)代汽車使用的智能感應(yīng)功能的范圍，以確保真正發(fā)生崩潰（不只是在路上顛簸或在停車場小碰撞），并在尋找