School of Automotive Studies, Tongji University, Shanghai, 201804, China.
Environ Sci Pollut Res Int. 2019 Sep;26(26):26617-26627. doi: 10.1007/s11356-019-05839-y. Epub 2019 Jul 10.
A comparative experiment was conducted based on a non-road diesel engine to investigate the effects of two after-treatment devices on the engine's emission characteristics as well as their power and fuel consumption performances. The first after-treatment device is a combination of a diesel oxidation catalyst (DOC) and a catalytic diesel particulate filter (CDPF). The second device is a single CDPF-coated improved noble metal catalyst. Results showed that the two after-treatment devices had almost no effect on the power and fuel consumption performance. The gaseous and particulate emissions of the engine depended on the operation conditions including the speed and load. However, the dual DOC+CDPF system and the single CDPF reduced more than 81% of the carbon monoxide (CO) and 73% of the hydrocarbon (HC) emissions. Notably, the reduction efficiency by the single CDPF was higher than that of the DOC+CDPF system. In terms of the particulate emissions, both after-treatment devices achieved more than 96% reduction of the particle number (PN) and up to 88% reduction of the particulate mass (PM). Similarly, the single CDPF outperformed the dual DOC+CDPF system in reducing particle emissions. Although no changes occurred in the bimodal particle size distribution of the engine after the installation of the two after-treatment devices, they performed differently in reducing particles with different sizes. The particles reduction efficiency of the DOC+CDPF system was higher than that of the single CDPF for the particles smaller than 14.3 nm, and this trend converted for particles larger than 14.3 nm. Improving the noble metal catalyst load in the CDPF ensured a performance that rivaled the DOC+CDPF system. Apart from the NOx emissions, the installation of a single CDPF with an improved noble metal catalyst load can make the non-road diesel engine meet the limits of the China IV emission regulations.
基于非道路柴油机进行了对比试验，研究了两种后处理装置对发动机排放特性及其功率和燃油消耗性能的影响。第一种后处理装置是柴油机氧化催化剂（DOC）和催化式柴油机微粒过滤器（CDPF）的组合。第二种装置是单独涂覆改进型贵金属催化剂的 CDPF。结果表明，两种后处理装置对功率和燃油消耗性能几乎没有影响。发动机的气体和微粒排放取决于包括转速和负荷在内的运行条件。然而，双 DOC+CDPF 系统和单 CDPF 将一氧化碳（CO）和碳氢化合物（HC）排放量减少了 81%以上。值得注意的是，单 CDPF 的减排效率高于 DOC+CDPF 系统。就微粒排放而言，两种后处理装置都实现了超过 96%的微粒数量（PN）减少和高达 88%的微粒质量（PM）减少。同样，单 CDPF 在微粒减排方面优于双 DOC+CDPF 系统。尽管在安装两种后处理装置后发动机的双峰颗粒尺寸分布没有变化，但它们在减少不同尺寸的颗粒方面表现不同。DOC+CDPF 系统对小于 14.3nm 的颗粒的减排效率高于单 CDPF，而对于大于 14.3nm 的颗粒则相反。提高 CDPF 中贵金属催化剂的负载量可以确保其性能与 DOC+CDPF 系统相媲美。除了 NOx 排放外，安装具有改进型贵金属催化剂负载量的单 CDPF 可以使非道路柴油机满足中国 IV 排放标准的限制。
