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一单元Fast,cleanandenergyefficient,thesteam-poweredcarwasatonetimethemotorist’svehicleofchoice.Sowhydiditrunoutofpuff?快速、清洁、节能，蒸汽动力汽车曾是汽车驾驶者的首选。那么为什么它的气都用光了呢？Mentionsteamenginesandmostpeoplewillthinkofsteamtrains,notsteamcars.Butthishasnotalwaysbeenthecase.Attheturnofthe20thcenturymorethanhalfthecarsintheUSAwerepoweredbysteam.MainlyproducedbytheAmericancompaniesStanleyandWhite,steamengineshadaseriesofadvantagesoverthenewerinternalcombustionengine.一提到蒸汽机，大多数人就会想到蒸汽火车，而不是蒸汽火车。但情况并非总是如此。在20世纪之交，美国一半以上的汽车是由蒸汽驱动的。主要由美国斯坦利和怀特公司生产，蒸汽机比新型内燃机有一系列的优势。Theyweresimplermechanically,producingcontinuouspowerfromsteampressuresotheyhadnoneedforthetransmission,clutchorgearsrequiredtoharnessandconvertthestrokesofacombustionengine.它们更简单，从蒸汽压力产生连续的动力，所以它们不需要传动装置、离合器或齿轮来利用和转换内燃机的冲程。Withfewmovingparts,theyranquietlyandcouldbefueledwithanythingthatburned.Theyproduced100%oftheirpowerfromrestsowerealsoeasiertodrive,andsaferforpedestrians.Theirpowercouldbeswitchedintoreverseatanypointtoreducespeedmorequicklythantheineffectivebrakesofthetime.由于几乎没有可移动的部件，它们可以悄悄地跑起来，用燃烧的任何东西来补充能量。他们从休息中产生了100的能量，因此也更容易驾驶，对行人也更安全。它们的动力可以在任何时候转变为倒车，以比当时无效的刹车更快地降低速度。Butsteamcarsalsohaddisadvantages.Theyweremorecumbersomethantheirsmallerrivals,oftenweighingbetweentwoandthreetonnes.Substantialboilersandwatertankswereneededwithearlysteamcarslosinguptoagallon(4.5litres)ofwatereverymile.Stanleypartiallyremediedthiswiththeintroductionofcondensersin1915,whichturnedmuchofthesteambacktoliquidwaterbeforeitcouldescape.Buteventhentheywerestillonlyachievingeightmilespergallonofwater.但蒸汽汽车也有缺点。它们比规模较小的竞争对手要笨重，通常重量在两到三吨之间。大量的锅炉和水箱是必要的，早期的蒸汽汽车每英里会损失1加仑（4.5升）的水。斯坦利在1915年引进冷凝器，部分地弥补了这一点。冷凝器在蒸汽逃逸前就把大部分蒸汽重新变成了液态水。但即使如此，每加仑水也只能行驶8英里。Anotherdrawbackwashowlongittooktobuildupsteampressurebeforeajourneycouldbegin.AStanleysteamerowner’smanualpublishedin1918suggestedthatthiswouldtakebetween10and15minutes,butincoldweatheritwaslikelytotakemuchlonger.另一个缺点是，在旅行开始之前，需要多长时间才能产生蒸汽压力。1918年出版的斯坦利轮船所有者手册指出，这将需要10到15分钟，但在寒冷的天气下，这可能需要更长的时间。Startinghadalsobeenanissueforcarspoweredbythenewcombustionengines.Earlymodelsrequiredhand-operatedcrankstostartwhichcouldbreakarmsandwristswhenthecarbackfired.Buttheinventionoftheelectricstartergavetheinternalcombustionengineanadvantageandledlargemanufacturingcompaniestoinvest.对于新的内燃机驱动的汽车来说，起动也是个问题。早期的车型需要手动曲柄来启动，当汽车发生逆火时，曲柄可能会折断胳膊和手腕。但电起动器的发明给了内燃机一个优势，并导致大型制造企业进行投资。By1910,carswithinternalcombustionengineswerebeingchurnedoutinhugenumbersatpricessolowthatthesmallersteamcarmanufactureshadnochanceofmatchingthem.Soon,theFordModelTtooktheStanley’scrownasthemostpopularcaronAmericanroads.到了1910年，内燃机汽车以极低的价格大量生产出来，小蒸汽汽车制造商根本没有机会与之匹配。很快，福特T型车就成为了美国公路上最受欢迎的车。Steamcarmakersadaptedtotheirmarginalization,marketingtheircarsasluxuryproducts.Stanleytookoutnewspaperadvertsemphasizingthe“soft,smooth,glidingmotion,”tohelpreaders“(recognize)thefundamentalsuperiorityofsteam,”astheyputit.蒸汽汽车制造商适应了他们的边缘化，把他们的汽车当作奢侈品来销售。斯坦利拿出报纸广告，强调“柔软，流畅，滑行的动作”，以帮助读者“（承认）Steam的根本优势，”正如他们所说。Butby1918theStanleySteamerwasalmostsixtimesthepriceofaModelT.TheStanleyCompanydeclinedandeventuallystoppedtradingin1924,bywhichpointsteamcarswereconsideredarareandantiquatednovelty.但到了1918年，斯坦利蒸汽机车的价格几乎是T型车的六倍。斯坦利公司(StanleyCompany)在1924年下跌，并最终停止了交易。到那时候，蒸汽汽车被认为是一种罕见的过时的新奇玩意儿。Sincethen,steamcarshaveallbutdisappearedfromroads.However,manyhavebeenpreservedbyenthusiastslikeAlunGriffiths,SecretaryoftheSteamCarClubofGreatBritain,whoownsa1916StanleySteamer.从那以后，蒸汽汽车几乎从道路上消失了。然而，很多都被像英国蒸汽汽车俱乐部的秘书阿伦·格里菲斯这样的狂热者所保存，他拥有一艘1916年的斯坦利轮船。“(Ihear)thewindwhistlinginthehoodfittingsandnoothersoundapartfromafaintthump,thumpfromthefeedwaterpumps,likethebeatofthemachine’sheart.”“风在引擎盖里呼呼地吹着，除了从给水泵里发出的微弱的砰砰声，没有别的声音，就像机器的心脏在跳动“Ithasbeensaidofsteamcars,andofsteamenginesgenerally,thattheyseemalivecomparedtootherpiecesofmachinery,andIcanonlyagreewiththat.”“有人说蒸汽车，以及一般的蒸汽机，和其他机器相比，它们似乎是活的，我只能同意这一点。”Butaresteamcarsconsignedtothepast,anowobsoletesteppingstoneinautomotivehistory?Perhapsnot.但是，蒸汽汽车已经成为汽车历史上过时的垫脚石了吗？也许不。Internalcombustionengineshavetheirowninherentdrawbacks.Theydependonfossilfuels,afiniteresourcelikelytobecomeevermoreexpensive.Andtheyproducepollutantsincludingcarbonmonoxideandnitrogenoxides.内燃机有其固有的缺点。它们依赖于化石燃料，这是一种有限的资源，可能会变得越来越昂贵。它们产生的污染物包括一氧化碳和氮氧化物。Steamcarscouldusearangeoffuelsandtheircontinuouspower–availableevenwhentheyareatrest–lendsitselftomoderntraffic,withonlylighttouchesofthethrottleandbrakeneededtostopandstart.蒸汽汽车可以使用一系列的燃料，而且它们的连续动力–即使它们处于静止状态也能–使其适合现代交通，只需轻微的油门和刹车就可以停止和启动。Moderntechnologycouldreducemanyofthehistoricproblemsofsteamcars.Lightweightmaterialsandheatresistantcoatingscoulddrasticallyreducetheweightoftheboilerandcondenser,andwaterretentioncouldbemaximised.Starttimeswithmodernboilerscouldbereducedfromminutestoseconds.现代技术可以减少蒸汽汽车的许多历史问题。轻质材料和耐热涂层可以大幅度降低锅炉和冷凝器的重量，最大限度地保持水的能力。现代锅炉的启动时间可以从分钟减少到秒。Somecarcompanieshaveresearchedanddevelopedsteamtechnologyovertheyears,mostnotablyinthe1990swiththeVolkswagenspin-offEnginionAG.Thiswasasteamenginewithefficiencycomparabletomoderninternalcombustionengineswithloweremissi