According to the bench test experience of China Ⅵ diesel engine, a large difference of NOx content occurred between NOx sensor of downstream of some SCR system and bench gas analyzer. Two SCR schemes were calculated by using computational fluid dynamics (CFD) technology, and the shape of urea spray and the evaporation and decomposition were analyzed. Then the uniformity of ammonia distribution on the front face of SCR carrier and the installation position of NOx sensor was evaluated. The proportion of ammonia distribution deviation at NOx probe was further analyzed. The simulation results show that the ammonia unevenness before SCR is the reason of NOx deviation. The deviation reduces from 15% to 0.5% after introducing the mixing device at downstream of SCR substrate, which solves the problem of large deviation. The bench test shows that the simulation and test results are in good agreement, which proves the credibility of CFD analysis.
BIAN Zengtao
,
WANG Fengshuang
,
LIU Xinglong
,
LI Junpu
,
GENG Lei
,
LI Zhaoyang
. Monitoring Characteristic of NOx Sensor Based on CFD[J]. Vehicle Engine, 2021
, 0(4)
: 86
.
DOI: 10.3969/j.issn.1001-2222.2021.04.013
