连续再生颗粒捕集器对柴油机颗粒排放的影响

Effects of Continuously Regenerating Diesel Particulate Filter on Characteristics of Particle Size Distribution from a Diesel Engine

摘要:

以某重型柴油机为原机，研究氧化催化转化器（DOC)与催化型颗粒捕集器（CDPF）耦合而成的连续再生颗粒捕集器(CRDPF)对柴油机颗粒排放规律的影响.研究结果表明，CRDPF的安装导致排气温度升高；原机测点颗粒数量浓度呈双峰对数正态分布，CRDPF的前测点为三峰对数正态分布，后测点则呈多峰对数正态分布；前测点粒径小于191nm颗粒数量浓度及核态颗粒数量浓度分数均高于原机测点；CRDPF除对7~15 nm粒径颗粒的捕集效率相对较低，对其他粒径颗粒具有显著的降低作用；对聚集态颗粒的捕集效果优于核态颗粒，导致后测点核态颗粒数量浓度分数高于前测点.

Abstract:

A heavy diesel engine was tested on the engine test bench to analyze the two different particulate emissions results of the original engine and the engine with continously regenerating Diesel Particultc Filfer CRDPF equipment. Results show that the application of CRDPF increases the exhaust temperature. The particle number size distribution of original engine clearly shows a bimodal and lognormal. The particle number size distribution upstream of the CRDPF shows trimodal and turns into multimodal across the CRDPF. The test engine with CRDPF generates more particles in diameter below 191nm than the original one. The nuclei mode particles upstream of CRDPF give a larger fraction than the original one. Particulate emission decreases dramatically across the CRDPF except the particles in diameter ranging from 7nm to 15nm. The reduction ratio of accumulation mode particles is higher than that of nuclei mode particles. This leads to an increase in the proportion of nuclei mode particles downstream.