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GAC China says it's building "world first" ammonia engine for cars
Ammonia has been proposed as a clean fuel for ships, airliners, trucks and trains, but China's GAC believes it could also have a future in passenger cars. It's built a combustion engine to test the theory, capable of reducing emissions by around 90%.
Ammonia (NH3) carries hydrogen better than hydrogen carries hydrogen, in some regards. It's easier to handle, since it's liquid at ambient temperatures, and it thus doesn't require energy-hungry compression or cryogenic liquefaction gear.
You can make it cleanly – although that's not how the overwhelming majority of it is made today. It's also highly caustic, and an "extremely hazardous substance" to humans and many animals alike. So it's got plenty of cons along with its pros – not that gasoline or diesel don't have their own issues.
While many green ammonia vehicle projects aim to "crack" the ammonia back into hydrogen, release the nitrogen back into the air and run a fuel cell to create electric power, others use it in modified combustion engines. And that's what we're looking at today.
Guzngzhou Automotive Group Co. (GAC) announced at a recent Tech Day presentation that it had developed a 2.0-liter engine capable of burning liquid ammonia safely and efficiently. According to Bloomberg, GAC claims a 120 kW (161 hp) peak power output, and a 90% reduction in carbon emissions compared to conventional fuels.
Is it a "world first?" Eh, maybe. Researchers at the Korean Institute for Energy Research built and tested a car called AmVeh a decade ago, which ran on 70% ammonia, 30% gasoline. It cut down carbon emissions by 70%, and at the time, the AmVeh team was definitely focused on the idea of a fully ammonia-fueled engine.
Given that the GAC engine still appears to create some carbon dioxide, there's possibly some other fuel source going in there as well. That'd make sense, as the low propagation speed of flame in ammonia tends to make engines struggle at high RPMs or low engine loads.
GAC will face other challenges if it truly wants to bring ammonia engines to the auto world – not the least of which will be a complete lack of fueling infrastructure, although this might give the industry breathing room to create a fueling system that'll keep humans safe from this highly toxic substance.
But there's also its pretty much unavoidable tendency to create high levels of NOx emissions – and in the case of diesel-adjacent compression style engines, the problem of having unburned ammonia coming out of the tailpipe as well. And of course the fact that most of today's ammonia is made using the high-emissions haber-bosch process.
Still, we'll be interested to see where this concept goes, if it makes it past a simple tech day presentation. Which it may not.
注释：
Ambient :n; adj
1. n表示"环境"，如：Deathes from ambient carbon monoxide poisoning are increasing. 由周围环境一氧化碳引起的中毒死亡人数越来越多。
2. adj表示" 周围的；氛围的"，means "completely enveloping"，如：t is reported that the ambient air over the city is becoming worse and worse. 据报导该城市上空周围的空气越来越糟。
cryogenic: adj
表示" 低温的；冷冻的"，means "of or relating to very low temperature"，如：All cryogenic liquids are extremely cold. 所有低温液体的温度都极低.
liquefaction
表示" 液化；溶解；"，means "the conversion of a solid or a gas into a liquid"，如：It must be cooled to its liquefaction temperature. 它必须冷却到其液化温度。
caustic: adj
表示" 腐蚀性的；刻薄的"，means "of a substance, especially a strong acid; capable of destroying or eating away by chemical action;harsh or corrosive in tone"，如：Zinc is generally caustic to foliage. 锌常对幼叶有腐蚀作用. He opened his mouth to make a caustic retort. 他张嘴开始进行刻薄的反击。
propagation: n
表示"繁殖；传播"，means "the act of producing offspring or multiplying by such production"，如：Rose propagation has a long and rich history. 玫瑰繁殖有着悠久的历史。
tailpipe: n
表示"排气管"，means "a pipe carrying fumes from the muffler to the rear of a car"，如：Burning that much gasoline sends around three tons of carbon dioxide out the tailpipe.燃烧这麽多的汽油，会从排气管送出约三公吨的二氧化碳。
haber-bosch：n
表示"哈伯-博施法,一种通过氮气及氢气产生氨气（NH3）的方法".
中文简要说明：
如何实现净零碳排? 最主流的方式就是电动化，不过也有其他另类选择，比如氢燃料，但是氢燃料比较不好储存，于是「氨燃料」（阿摩尼亚）也被提出，也就是氨气动力。现在中国大陆的广州汽车集团(GAC Group,广汽)就发明了汽车版本的氨动力引擎，来测试这一理论。
新阿特拉斯(New Altas)报导，氨气 (NH3)在很好制作，它的主要成份就是氮气，早在100多年前，德国化学家哈伯(Fritz Habe)就提出有效的大量制氨方法，称为「哈伯法」。氨气在普通情况无法燃烧，但是特殊情况下(纯氧环境)可以成为燃料，它在环境温度下是液体，因此不需要耗能的压缩或低温液化装置。
目前许多氨动力汽车的计划，是先将氨分解回氢气+氮气，氮气随后释放回空气中，并不影响环境，而氢气可以做为燃料电池的燃料，不过广汽集团的做法是将它做为内燃机的燃料。
广汽在最近的科技日演讲中宣布，他们已开发出一款能够安全高效燃烧液态氨的 2.0升发动机。据媒体报导，其峰值功率输出为 120千瓦（约161马力），与现有汽车引擎功率差不多，碳排放量减少了 90%。
这听起来颇为理想，但是也有不少待改善的地方，比如「减少90%」这句话，显然这具引擎不是纯氨燃料，而是混有其他其他碳基燃料。这也合理，因为氨燃烧的火焰传播速度较低，往往会使引擎在高转速或低负载下出现停止。
另外，氨有明显的刺鼻性，而且也对铁材具有腐蚀性，这使得它的加燃料工作必须特别注意。
还有，虽然它能降低碳排放，但是氨燃烧后的「氮氧化物」，同样也是有害的废气，同样不算环保。尽管如此，我们还是有兴趣看看这个概念能走向何方，许多发明不见得一定有成果，但可能是其他新发明的基础。
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