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《内燃机学报》[ISSN:1006-6977/CN:61-1281/TN]

卷:

期数:

2022年03

页码:

240-247

栏目:

出版日期:

2022-05-25

文章信息/Info

Title:

Synergistic Effect of O2-NO2 on Soot Oxidation from Diesel Engine Exhaust

作者:

张韦; 李泽宏; 陈朝辉; 孙富贤; 杨喜力; 彭益源

1. 昆明理工大学 云南省内燃机重点实验室，云南 昆明 650500； 2. 昆明云内动力股份有限公司，云南 昆明 650224

Author(s):

Zhang Wei; Li Zehong; Chen Zhaohui; Sun Fuxian; Yang Xili; Peng Yiyuan

1. Yunnan Key Laboratory of Internal Combustion Engine，Kunming University of Science and Technology， Kunming 650500，China；2. Kunming Yunnei Power Corporation Limited，Kunming 650224，China

关键词:

柴油机; 碳烟; 协同效应; 密度泛函理论; 化学动力学

Keywords:

diesel engine; soot; synergistic effect; density functional theory; chemical kinetics

分类号:

TK442

文献标志码:

A

摘要:

柴油机排气温度低于873K时难以直接氧化碳烟，使得柴油机颗粒捕集器(DPF)要实现低温、高效率的再生面临严峻考验，为了明确DPF内O2-NO2快速氧化碳烟的反应机制，基于量子化学与化学动力学，采用微观机理结合宏观分析的手段，探究了O2-NO2协同氧化碳烟的机理，并对碳烟的氧化进行定性与定量分析．研究表明：O2-NO2对碳烟的活性位有竞争吸附作用，NO2的吸附能明显高于O2，但O2与碳烟更易形成C(O)及活性O*．NO2易与O2产生的C(O)反应，生成的NO3-可有效氧化活性C*，实现O2-NO2对碳烟氧化的协同效应；中等温度为742K时，O2与A4-反应生成A4O的量保持最多，且O2与NO2摩尔分数比为1/2时，A4-的10s再生效率最高可达78.1%，NO2摩尔分数越大，则更易于触发协同反应机制，A4-的氧化速率也越快．

Abstract:

It is a severe challenge for the diesel particulate filter(DPF)to achieve low-temperature and high-efficiency regen-eration because soot is difficulty to be oxidized when the diesel engine exhaust temperature is below 873K. In or-der to determine the reaction mechanism of O2-NO2 rapidly oxidizing soot in the DPF，the mechanism of O2-NO2 synergistic oxidation of soot was explored and the soot oxidation was analyzed qualitatively and quantitatively based on quantum chemistry and chemical kinetics using microscopic mechanism combined with macroscopic anal-ysis. Results show that the O2 and NO2 have a competitive adsorption effect on active sites of soot. The adsorption energy of NO2 is significantly higher than that of O2，but O2 is more likely to form C(O)compounds and active O*. NO2 easily reacts with C(O)produced by O2 to generate NO3- which effectively oxidizes active C* atoms，realizing synergistic effect of O2-NO2 on soot oxidation. When the medium temperature is 742K，the amount of A4O produced by the reaction between O2 and A4- remains the largest，and when the O2/NO2 ratio is 1/2，the maximum 10s regeneration efficiency of A4- is 78.1%. The larger the proportion of NO2，the greater the reaction prone to synergistic reaction mechanism，the faster the oxidation rate of A4-.

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更新日期/Last Update: 2022-05-25