Sulfur Driven Nucleation Mode Formation in Diesel Exhaust under Transient Driving Conditions
Sulfur Driven Nucleation Mode Formation in Diesel Exhaust under Transient Driving Conditions
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DOI：
10.1021/es405009g
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发表时间：
2014-02-18
影响因子：
11.4
通讯作者：
Keskinen, Jorma
中科院分区：
文献类型：
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作者：
Karjalainen, Panu;Ronkko, Topi;Keskinen, Jorma
在气溶胶实验室、发动机测功机和道路上研究了硫驱动的柴油机排气核化颗粒的形成过程。所有测试发动机都配备有柴油氧化催化剂（DOG）和部分柴油颗粒过滤器（pDPF）的组合。在稳定操作条件下，半挥发性成核粒子的形成直接取决于催化剂中SO2的转化率。在发动机负荷和排气温度迅速增加后，核化颗粒排放最为显著。结果表明，在瞬态驱动条件下的成核粒子的形成不需要化合物，如烃或硫酸化烃，但是，它不能被解释为仅由硫酸的成核。对重型柴油卡车的实际排气研究表明，即使在超低硫柴油燃料下，即使在下坡行驶条件下，也会发生成核颗粒形成，并且成核颗粒可占总颗粒数排放的60%。通常，由于硫在排气后处理系统内的储存和释放以及驾驶中的瞬态，成核颗粒的排放甚至可以是现代柴油车辆排气颗粒物数量排放的主要部分。
Sulfur driven diesel exhaust nucleation particle formation processes were studied in an aerosol laboratory, on engine dynamometers, and on the road. All test engines were equipped with a combination of a diesel oxidation catalyst (DOG) and a partial diesel particulate filter (pDPF). At steady operating conditions, the formation of semivolatile nucleation particles directly depended on SO2 conversion in the catalyst. The nucleation particle emission was most significant after a rapid increase in engine load and exhaust gas temperature. Results indicate that the nucleation particle formation at transient driving conditions does not require compounds such as hydrocarbons or sulfated hydrocarbons, however, it cannot be explained only by the nucleation of sulfuric acid. A real-world exhaust study with a heavy duty diesel truck showed that the nucleation particle formation occurs even with ultralow sulfur diesel fuel, even at downhill driving conditions, and that nucleation particles can contribute 60% of total particle number emissions. In general, due to sulfur storage and release within the exhaust aftertreatment systems and transients in driving, emissions of nucleation particles can even be the dominant part of modern diesel vehicle exhaust particulate number emissions.