汽车工程 ›› 2021, Vol. 43 ›› Issue (3): 350-357.doi: 10.19562/j.chinasae.qcgc.2021.03.007

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排气温度、排气流量和海拔高度对SCR系统NOx转化率和NH3泄漏量的影响研究

毕玉华1,聂学选1,刘少华1(),肖奔1,王鹏1,申立中1,彭益源2   

  1. 1.昆明理工大学,云南省内燃机重点实验室,昆明 650500
    2.昆明云内动力股份有限公司,昆明 650500
  • 收稿日期:2020-09-20 修回日期:2020-11-13 出版日期:2021-03-25 发布日期:2021-03-26
  • 通讯作者: 刘少华 E-mail:1119175410@qq.com
  • 基金资助:
    国家自然科学基金重点项目(51765025);云南省基础研究重点项目(2018FA030);云南省重大科技专项计划项目(2018ZE001)

Study on the Effects of Exhaust Temperature, Exhaust Flow Rate and Altitude on NOx Conversion Rate and NH3 Slip of SCR System

Yuhua Bi1,Xuexuan Nie1,Shaohua Liu1(),Ben Xiao1,Peng Wang1,Lizhong Shen1,Yiyuan Peng2   

  1. 1.Kunming University of Science and Technology,Yunnan Key Laboratory of Internal Combustion Engine,Kunming 650500
    2.Kunming Yunnei Power Co. ,Ltd. ,Kunming 650500
  • Received:2020-09-20 Revised:2020-11-13 Online:2021-03-25 Published:2021-03-26
  • Contact: Shaohua Liu E-mail:1119175410@qq.com

摘要:

为研究不同海拔下SCR系统性能,分别在80、90、100 kPa大气压力下对一台满足国五排放标准的高压共轨柴油机进行性能与排放试验,以研究排气温度、排气流量和海拔变化对NOx转化率和NH3泄漏量的影响。结果表明:在排气流量为350 kg/h情况下,NOx转化率随排气温度升高呈现先增后减的趋势,不同温度下NOx转化率最大差值为43.4百分点;NH3泄漏量随着温度的升高大体上呈下降趋势,不同温度下NH3泄漏量最大差值为328×10-6;NOx转化率随排气流量升高呈现先增后减的趋势,在250 ℃时,不同排气流量下NOx转化效率最大相差21.5百分点;NH3泄漏量随排气流量的增大而增加,在250 ℃时,不同排气流量下NH3泄漏量最大差值为90.8×10-6。相同工况下,海拔越高,NOx转化率越高,NH3泄漏量越小,大气压力为80和100 kPa下NOx转化率最大相差20.1百分点,NH3泄漏量最大相差54.6×10-6

关键词: 柴油机, 海拔, SCR系统, NOx转化效率, NH3泄漏量

Abstract:

In order to study the performance of SCR at different altitudes, the performance and emission tests on a high?pressure common?rail diesel engine meeting the national?V emission regulation are conducted under 80、90 and 100 kPa atmospheric pressures respectively to study the effects of exhaust temperature, exhaust flow rate, and altitude on NOx conversion rate and ammonia slip. The results show that under an exhaust flow rate of 350 kg/h, with the increase of exhaust temperature, the NOx conversion rate exhibits a tendency of rises first and then falls, with the maximum difference of NOx conversion rate of 43.4 percentage points at different exhaust temperatures; The ammonia slip by and large reduces with the rise in exhaust temperature, and the maximum difference of ammonia slip is 328×10-6 at different temperatures. The NOx conversion rate show a trend of rise first and then fall as the exhaust flow rate increases, with a maximum difference of NOx conversion rate of 21.5 percentage points at different exhaust flow rates when the exhaust temperature is 250 ℃; The ammonia slip increases with the increase of exhaust flow rate, and the maximum difference of ammonia slip is 90.8×10-6 at different exhaust flow rates when the exhaust temperature is 250 ℃. Under the same working conditions, the higher the altitude, the greater the NOx conversion rate and the smaller the ammonia slip, and when the atmospheric pressure lowers from 100 kPa to 80 kPa, the maximum NOx conversion rate rises by 20.1 percentage points and the maximum ammonia slip reduces by 54.6×10-6.

Key words: diesel engine, altitude, SCR system, NOx conversion rate, ammonia slip