选择性催化还原系统：发现“氮氧化物杀手”

The Selective Catalytic Reduction (SCR) system is an advanced system used in diesel engines that can reduce NOx emissions by up to 90%. Find out all you need to know.

选择性催化还原（SCR）系统是用于柴油发动机的高级系统，可最高达到90%的氮氧化物减排。找到您需要知道的全部内容。

SCR systems: A quick history

SCR系统：快速了解

SCR has been used for decades to reduce stationary source emissions. In addition, many marine vessels such as cargo vessels, ferries and tugboats are equipped with SCR technology. Today, thanks to its affordability and efficiency in reducing emissions, SCR is becoming the emissions control technology that is key to meet the EURO V and VI norms for commercial vehicles.

SCR已经使用了数十年，以减少固定源排放。此外，许多船舶，如货船、渡轮和拖船都配备了SCR技术。今天，由于SCR在减排方面的可承受性和效率，其正成为商用车符合EURO V和VI规范的关键性排放控制技术。

How a SCR system works

SCR系统如何工作

SCR employs active emissions control technology. Here’s how it works:

• A liquid-reductant agent is injected through a special catalyst into the exhaust stream of a diesel engine. The reductant source is usually an automotive-grade urea, otherwise known as Diesel Exhaust Fluid (DEF).
• The DEF sets off a chemical reaction that converts nitrogen oxides into nitrogen, water and tiny amounts of carbon dioxide (CO2), natural components of the air we breathe.
• These components are then expelled through the vehicle tailpipe.

SCR采用主动排放控制技术。其工作原理如下：

• 液体还原剂通过一种特殊催化剂注入柴油发动机的废气中。该还原剂源通常为一种汽车级尿素，也称为柴油机尾气处理液（DEF）。
• DEF激发一种化学反应，将氮氧化物转化为我们呼吸空气中的天然成分氮气、水和微量二氧化碳（CO2）。
• 然后这些成分通过车辆尾管排出。

Why SCR is important?

为什么SCR很重要？

All heavy-duty diesel truck engines produced after January 1, 2015 must meet the latest EURO VI emissions standards. This goes for off-road equipment, including construction and agricultural equipment as well.

2015年1月1日之后生产的所有重型柴油卡车发动机必须符合最新的EURO VI排放规范。此规范适用于越野设备，包括建筑和农业设备。

The EURO VI standards are among the most stringent in the world and demand that particulate matter (PM) and nitrogen oxides (NOx) are reduced to near zero levels. To accomplish this, SCR technology is one of the most cost-effective and fuel-efficient technologies available today.

EURO VI规范是世界上最严格的规范之一，要求颗粒物（PM）和氮氧化物（NOx）降至接近零水平。为实现这一目标，SCR技术是当今最具成本效益和燃油效率的技术之一。

SCR can reduce NOx emissions up to 90 percent while simultaneously reducing HC and CO emissions by 50-90 percent, and PM emissions by 30-50 percent. When combined with a diesel particulate filter, the emission of PM further decreases.

SCR可将NOx排放降低90％，同时将碳氢化合物（HC）和一氧化碳（CO）排放量降低50-90％，PM排放量降低30-50％。当与柴油颗粒过滤器结合使用时，PM的排放进一步减少。

But SCR has another benefit. In the commercial trucking industry, some SCR-equipped truck operators report fuel economy gains of 3-5 percent!

但是SCR还有另一个好处。在商业卡车运输行业，一些配备SCR的卡车运营商报告燃油经济性增长了3-5％！

About Diesel Exhaust Fluid (DEF), the ‘fuel’ of a SCR system

关于柴油机尾气处理液（DEF），SCR系统的“燃油”

SCR requires that you regularly replenish the Diesel Exhaust Fluid (DEF).

SCR要求您定期补充柴油机尾气处理液（DEF）。

DEF is an aqueous urea solution made with 32.5% urea and 67.5% deionized water. This solution is named AUS 32 in ISO 22241, and the German Association of the Automotive Industry (VDA) registered the trademark AdBlue for the same product. In short, AdBlue equals AUS 32 equals Diesel Exhaust Fluid.

DEF是由32.5％尿素和67.5％去离子水制成的尿素水溶液。该解决方案在ISO 22241中命名为AUS 32，德国汽车工业协会（VDA）在同一产品中注册了AdBlue商标。简言之，AdBlue等于AUS 32等于柴油机尾气处理液。

DEF is now widely available in various size containers such as bulk, totes and bottles or jugs.

DEF目前广泛用于各种尺寸的容器，例如散装、手提袋及瓶或壶装。

Maintaining the proper level of DEF is essential

保持适当的DEF水平至关重要

DEF is carried in an onboard tank. Tractor trailers typically have a DEF tank alongside the diesel fuel saddle tank.

DEF通过车载水槽运输。拖拉机拖车通常在柴油燃料鞍缸旁边有一个DEF槽。

DEF must be periodically replenished by the operator based on vehicle and operation:

• For light-duty vehicles, DEF refill intervals typically run parallel with recommended oil change intervals.
• For heavy-duty vehicles and off-road machines and equipment, the interval will vary depending on the operating conditions, hours used, kilometers travelled, load factors and other considerations.

操作员必须根据车辆和操作要求定期补充DEF：

• 对于轻型车辆，DEF补充周期通常与推荐的换油周期并行。
• 对于重型车辆和越野机器和设备，补充周期将根据运行条件、使用小时数、行驶公里数、负载系数和其他考虑因素而变化。

Low DEF supply triggers a series of escalating visual and audible indicators to the driver or operator. Once the tank reaches a certain level near empty, a vehicle might not even start before DEF is refilled. Proper storage of DEF is required to prevent the liquid from freezing at temperatures below minus 11 degrees Celsius, and most vehicle DEF dispensing systems have warming devices.

低DEF供应会向驾驶员或操作员触发一系列不断升级的视觉和听觉指示器。一旦DEF槽达到接近用完的某个水平，在重新补充DEF之前，车辆甚至可能无法启动。需要适当储存DEF以防止液体在低于零下11摄氏度的温度下冻结，并且大多数车辆DEF分配系统配有加温装置。

You can purchase DEF at truck stops, truck dealerships and engine distributors.

您可以在卡车停靠站、卡车经销商和发动机经销商处购买DEF。

Summary:

• SCR is becoming the emissions control technology that is key to meet the EURO V and VI norms for commercial vehicles.
• SCR employs active emissions control technology to convert nitrogen oxides into the natural components of the air we breathe.
• SCR technology is one of the most cost-effective and fuel-efficient technologies available to meet the EURO VI norms.
• Maintaining the proper level of DEF, also AdBlue, is essential.

总结：

• SCR正在成为符合商用车EURO V和VI标准的关键性排放控制技术。
• SCR采用主动排放控制技术将氮氧化物转化为我们呼吸的空气中的天然成分。
• SCR技术是现有符合EURO VI规范的最具成本效益和燃油效率的技术之一。
• 保持适当水平的DEF、以及AdBlue至关重要。