形态参数对催化型颗粒捕集器性能的影响

Influence of Morphological Parameters on Performance of Catalytic Particulate Filter

摘要:

催化型颗粒捕集器（CDPF）是当前最高效的柴油机颗粒减排技术，其性能与载体形态密切相关。以径长比表征形态，基于发动机台架试验研究了其对CDPF压降、气态物及颗粒物减排性能的影响。结果表明：CDPF排气背压随径长比的增大呈下降趋势，当径长比从0.93增大至1.15时，平均排气背压从4.03 kPa降至3.27 kPa，排气温度受径长比的影响较小。气态物减排方面：径长比越大，CO和THC（Total Hydrocarbon）的减排率越低。当径长比从0.93依次增大至1.15和1.42时，CO的减排率从44.5%分别降至41.7%和40.0%，THC减排率则由38.6%分别降至36.0%和34.3%。增大径长比，NOx排放浓度略微下降，但NO₂占比有所升高；颗粒物减排方面：CDPF可以实现92%以上的PN（Particulate Number）和PM（Particulate Matter）减排率，径长比增大，CDPF颗粒减排效果有所下降，积聚态颗粒减排效率下降更为明显。研究结论对优化设计CDPF结构具有重要参考价值。

Abstract:

Catalytic Diesel Particulate Filter （CDPF） is currently the most efficient technology for reducing diesel particulate emissions， and its performance is closely related to the morphology of the substrate. This paper characterizes the morphology using the aspect ratio and investigates its impact on the pressure drop， gaseous and particulate matter emission reduction performance of CDPF based on engine bench tests. The results indicate that the exhaust back pressure of CDPF decreases with an increase in aspect ratio. When the aspect ratio increases from 0.93 to 1.15， the average exhaust back pressure decreases from 4.03 kPa to 3.27 kPa， while the exhaust temperature is less affected by the aspect ratio. In terms of gaseous matter emission reduction， the larger the aspect ratio， the lower the emission reduction rates of CO and THC. When the aspect ratio increases from 0.93 to 1.15 and then to 1.42， the emission reduction rate of CO decreases from 44.5% to 41.7% and 40.0%， respectively， while the emission reduction rate of THC decreases from 38.6% to 36.0% and 34.3%， respectively. Increasing the aspect ratio slightly reduces NOx emission concentration， but increases the proportion of NO₂. In terms of particulate matter emission reduction， CDPF can achieve emission reduction rates of over 92% for PN and PM. As the aspect ratio increases， the particulate emission reduction effect of CDPF decreases， with a more significant decrease in the emission reduction efficiency of accumulated particulates. The research conclusions provide important reference value for optimizing the design of CDPF structure.