字神帝國英語天地

今日主題：Fuel-Efficient Engines Have a Sooty Flaw / 省油經濟型引擎可能噴射出更多污染物

洪欣老師推薦：托福聽力最好的課外教材：60-Second Science
康康精選托福會考的主題，堅持每天精聽一定會進步的哦!!

建議方法：
1. 先聽兩三遍 (不看文稿)
2. 再一句一句聽寫 (每句都要聽寫數遍，直到寫出85%以上的字)
3. 最後check文稿，看哪聽不出來，單字沒背過，還是發音不熟。
4. 堅持天天聽，就能每天進步哦。

MP3音檔 (按右鍵可下載聽)：喜歡的同學，幫忙推或按讚哦~~
http://online1.tingclass.net/voas…/2016/20160720sa_earth.mp3

只有音檔怎夠，聽不懂地方，不用怕，康康幫你準備好中英文稿了：

中英文稿：
If you've gone shopping for a car lately, you might have noticed that fuel economy—the number of miles per gallon—is creeping up. One reason is a more efficient type of fuel injection, called gas direct injection. It’s a feature of half the new cars sold in the U.S. last year.
如果你最近買了一輛車，你可能已經注意到——燃油經濟，每加侖行駛的總英里數正在蠕升。原因之一在於燃油噴射的效率更高，稱為缸內噴氣。這是去年所出售的一半新車所具有的一大特徵。

"With that kind of engine design you can also introduce turbocharging—that's really what it comes down to: more engine power with a smaller engine." Naomi Zimmerman, an air-quality scientist at Carnegie Mellon University—who has never owned a car. "Probably because I did a whole PhD on engine emissions."
Here's how the two injection methods differ. In the old standard, called "port fuel injection," gas is injected into the air intake, where it mixes with air before hitting the cylinder. In direct injection though, as the name implies, the fuel is injected directly into the cylinder. It's more fuel efficient, meaning lower CO2 emissions, which will help slow climate change. But paradoxically, it also emits more particulate matter, including black carbon, or soot—a pollutant implicated in global warming.
這種類型的引擎設計，也可以引進渦輪增壓——這才是真正的原因——更小馬力的引擎，更多的發動機功率。拿俄米齊默爾曼，卡內基梅隆大學一名空氣品質科學家——從未擁有一輛車。“可能是因為我博士研究生階段做了關於發動機排放的整體研究。這是這兩種噴射形式的不同之處。按照舊標準，稱之為“氣門式燃料噴射”，將氣體注入進氣口，在衝擊汽缸之前與空氣混合。然而，直接式燃料噴射，顧名思義，燃料直接注入汽缸，這樣更省油，意味著較低的二氧化碳排放，這將有助於減緩氣候變化。但是，與此相矛盾的是，也能噴射出更多的顆粒物。包括黑碳或煤灰——與全球變暖有直接關係的污染物。

Zimmerman and her colleagues analyzed studies of direct injection engines to see how this pollution tradeoff works out for the climate. "The answer is that it's really complicated and it's not certain." But on average, she says, boosting fuel economy five to nine percent would probably cancel out the warming effects of black soot, and score a net positive for the climate. The findings are in the journal Environmental Science and Technology. [Naomi Zimmerman et al., Assessing the Climate Trade-Offs of Gasoline Direct Injection Engines]
齊默爾曼與她的研究團隊對直噴式發動機的研究進行分析以查明這一污染權衡怎樣使氣候受益。“答案是，這真的很複雜，目前還不能確定。”但平均而言，她表示，將燃油經濟性由5%提高到9%，可能會消除黑炭的暖化效應，整體而言對氣候有益。該項研究結果發表在《環境科學與技術》雜誌上。

The fuel economy goal might be different in places with big temperature swings, and where gasoline has more aromatic compounds—which seem to boost black carbon emissions. One place that fits the bill: Canada. “There we might need to be closer to the 10 percent, 15 percent mark in terms of improving fuel economy. Which is actually a very aggressive increase in fuel economy."
燃油經濟性目標可能在那些溫度波動較大、汽油中含有更多芳香化合物的地方會有所不同——這似乎促進了黑碳排放。剛好符合要求的一個地方：加拿大。在這裡，就改善燃油經濟性而言，我們可能需要將其提高接近10%，15%，這的確是燃油經濟性的巨大極高。

She says one solution that might reduce black carbon emissions is gasoline particulate filters. Which would also screen out particulate matter dangerous to human health. Meaning a win for the planet—and the people who live on it.
她表示減少黑碳排放的一個可行的解決方案是汽油顆粒篩檢程式，它也可以篩選出對人類健康有危害的顆粒物。這意味著贏得了這個星球——並且人們在這個星球上生活。