School of Mechanical Engineering, Beijing Institute of Technology, Beijing 100081, China.
J Environ Sci (China). 2011;23(5):798-807. doi: 10.1016/s1001-0742(10)60452-4.
The effects of continuously regenerating diesel particulate filter (CRDPF) systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units (CRDPF-1 and CRDPF-2) with different specifications were separately retrofitted to the engine running with European steady-state cycle (ESC). An electrical low pressure impactor (ELPI) was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate (R(CR)) of hydrocarbons (HC) and carbon monoxide (CO) across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the R(CR) of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio (A/F) at higher loads.
本研究考察了连续再生式柴油颗粒过滤器（CRDPF）系统对发动机排放的气态污染物、颗粒数量和尺寸分布以及质量的影响。分别将两个具有不同规格的 CRDPF 装置（CRDPF-1 和 CRDPF-2）改装到使用欧洲稳态循环（ESC）运行的发动机上。采用电低压撞击器（ELPI）进行颗粒数量和尺寸分布测量和质量估算。CRDPF-1 对碳氢化合物（HC）和一氧化碳（CO）的转化/还原率（R(CR)）分别为 83%和 96.3%。同样，CRDPF-2 对 HC 和 CO 的 R(CR)分别为 91.8%和 99.1%。CRDPF 装置使颗粒数量浓度及其浓度峰值、核模态、积聚模态和总颗粒以及颗粒质量显著降低。CRDPF-1 和 CRDPF-2 下游的核模态颗粒分别减少了 99.9%至 100%和 97.8%至 99.8%；颗粒质量分别减少了 73%至 92.2%和 35.3%至 72.4%，具体取决于发动机条件。此外，由于较高的排气温度引发的非均相核化，核模态颗粒随发动机转速的增加而增加，而由于较高负荷下的空燃比（A/F）降低，积聚模态颗粒在较高负荷下更高。
