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汽车安全与节能学报 ›› 2012, Vol. 3 ›› Issue (1): 51-57.DOI: 10.3969/j.issn.1674-8484.2012.01.008

• 汽车节能与环保 • 上一篇    下一篇

柴油机LNT 浓燃过程中铑表面CO 还原NO 的详细反应机理

苏庆运1，王胜1，李艳宾1，帅石金2，王建昕2   

  1. 1. 大连理工大学 内燃机研究所，大连 116024 ；
    2. 清华大学 汽车安全与节能国家重点实验室，北京 100084
  • 收稿日期:2012-02-15 出版日期:2012-03-25 发布日期:2012-03-28
  • 作者简介:苏庆运（1975—），男（汉），山东，博士，硕士生导师，讲师。E-mail：qingyun@dlut.edu.cn
  • 基金资助:

    国家自然科学基金（50906008）；清华大学汽车安全与节能国家重点实验室开放基金（KF11181）；天津大学内燃机燃烧学国家重点实验室开放基金。

Detailed mechanism of NO reduction by CO over rhodium
during rich period of diesel LNT

SU Qingyun1, WANG Sheng1, LI Yanbin1, SHUAI Shijin2, WANG Jianxin2   

  1. 1. Institute of Internal Combustion Engine, Dalian University of Technology, Dalian 116024, China;
    2. State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing 100084, China
  • Received:2012-02-15 Online:2012-03-25 Published:2012-03-28

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摘要： 研究了在柴油机尾气稀燃NOx 捕集（LNT）技术再生阶段中，考虑了反应的副产物N2O，用CO
还原NO 的反应过程。建立了铑催化剂表面CO 还原NO 及N2O 的详细化学反应机理。分别对CO-NO
反应及不同进气比例下的CO-N2O 反应，进行了数值模拟，其结果与实验吻合良好。结果表明: N2O
是CO 还原NO 过程中的重要中间产物，且在一定条件下可继续被CO 还原。在475~620 K 温度区间
内，NO 还原过程主要是通过N2O 路径实现的。对于单独的CO-N2O 反应，研究了进气中CO 浓度的影响，
并通过对基元反应速率的分析，确定了反应的决速步为N2O 解离。

关键词: 柴油机, 稀燃NOx 捕集器（LNT）, 氧化亚氮, 一氧化碳, 铑催化剂, 详细机理

Abstract: The process of diesel exhaust NO reduction using CO as the reductant during the rich period of lean
NOx trap (LNT) was investigated considering an important byproduct N2O. Detailed mechanisms for CO-NO
and CO-N2O reactions over rhodium catalyst were proposed to numerically simulate experimental results, with
different feed gas ratios for the CO-N2O reaction. Good agreement was obtained for both of the two reactions.
The results show that N2O, as an important intermediate during NO reduction, undergoes further reactions with
CO under certain conditions. Most of the N2 is produced through the N2O route during NO reduction at 475-
620 K. The influence of the feed gas CO concentration on the isolated CO-N2O reaction was probed, and the
rate-limiting step was determined to be the decomposition of N2O according to the analysis of the elementary
reaction rate.

Key words: diesel engine, lean NOx trap (LNT), nitrous oxide (N2O), carbon monoxide (CO), rhodium catalyst, detailed mechanism

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