Taking China Ⅵ parallel SCR aftertreatment system as the research object, NOx emissions of two systems with different mixers were studied on a 13 L China Ⅵ diesel engine by using the calculation of velocity uniformity and ammonia uniformity, the analysis of twoway average ammonia concentration, the simulation of ammonia massweighted percentage, and the experiment of ammonia distribution uniformity and emission performance. The simulation results show that the calculated values of velocity uniformity and ammonia distribution uniformity of twoway parallel SCR aftertreatment systems are between 0.96 and 0.99, and the test results of ammonia concentration uniformity in the front end of single SCR are also beyond 0.98, but the relative deviation of average ammonia concentration in the front end of twoway SCR is between 5%-17%, which will result in poor NOx emission of aftertreatment. The simulation is verified by ammonia concentration test. According to the emission performance test, the WHTC emission results will become worse if the average ammonia concentration deviation is large. Accordingly, the parallel SCR aftertreatment catalytic capacity can be evaluated by the relative deviation calculation of ammonia massweighted percentage and it is thought to be reasonable that the calculation evaluation standard is set within 5%.
LIU Xinglong
,
Wang Jun
,
WANG Fengshuang
,
WANG Yuanjing
. Influence of Ammonia Distribution on NOx Emission of Parallel SCR Aftertreatment System for Diesel Engine[J]. Vehicle Engine, 2020
, 0(3)
: 50
-56
.
DOI: 10.3969/j.issn.1001-2222.2020.03.008
