排气催化转化装置对发动机排气颗粒物演化的影响

陈正国¹，杨小东²，刘庆阳¹，刘浩业^1*

1.天津大学先进内燃动力全国重点实验室，天津   300350；

2.无锡威孚力达催化净化器有限责任公司，江苏 无锡   214177

摘要：对一台汽油发动机催化转化装置上下游的非挥发性颗粒物和半挥发性颗粒物进行采样和分析，研究排气催化转化装置对发动机排气颗粒物演化的影响。结果表明：催化转化装置对排气颗粒物的影响包括直接过滤和去除成核前驱物两方面；催化转化装置可以直接过滤高温排气中的非挥发性颗粒，过滤效率为20%~35%，过滤过程包括颗粒物的捕集和氧化；催化转化装置还可以去除排气中半挥发性的多环芳烃成分，抑制该成分在排气温度降低后转化为半挥发性颗粒物。

关键词：颗粒物；催化转化装置；汽油发动机

The influence of exhaust catalytic converter on the evolution of engine exhaust particulate matter

CHEN Zhengguo¹, YANG Xiaodong², LIU Qingyang¹, LIU Haoye^1*

1.State Key Laboratory of Engines, Tianjin University, Tianjin 300350, China;

2.Wuxi Weifu Lida Catalytic Purifier Co., Ltd., Wuxi 214177, China

Abstract: To investigate the impact of the exhaust catalytic converter on the evolution of exhaust particles, the non-volatile particles and semi-volatile particles in the upstream and downstream of the exhaust catalytic converter of a direct injection gasoline engine are measured and analyzed. The results show that the influence of exhaust catalytic converter on exhaust particles includes two aspects: direct filtration and removal of nucleation precursors. Exhaust catalytic converter can directly filter non-volatile particles in high-temperature exhaust with a filtration efficiency of 20%-35%, and the filtration process includes the capture and oxidation of particles. Exhaust catalytic converter can also remove semi-volatile polycyclic aromatic hydrocarbons from the exhaust, thereby inhibiting the conversion of these components into semi-volatile particulate matter during the exhaust temperature reduction process in the exhaust.

Keywords: particulate matter; exhaust catalytic converter; gasoline engine