Volume allocation simulation analysis for dual SCR system in a diesel engine
WANG Jialin
WANG Chen
SUN Jianying
FENG Haidi
Abstract：In order to meet the increasingly stringent requirements for diesel engine pollutant emissions from constantly upgrading emission standards,AVL Cruise M software is used to establish a simulation model of a dual selective catalytic reduction(SCR)system.Based on the world harmonized transient cycle(WHTC),the impact of close-coupled SCR and under flow SCR volume allocation on NOx and N2O emissions,as well as urea injection,is analyzed.The results show that as the volume of close-coupled SCR decreases,the downstream cumulative NOx emissions first decrease and then increase,the cumulative N2O emissions gradually decrease,and the second stage urea injection advances.The volume of the under flow SCR increases,the NOx specific emissions decrease but the N2O specific emissions increase,and the second stage urea injection is delayed.The optimal volumes of close-coupled SCR and under flow SCR are 1/3 V and V(V is the current volume of SCR in a China Ⅵ engine),respectively.At this time,the corresponding cold WHTC,hot WHTC,and weighted NOx specific emissions are 0.609,0.037,and 0.119 g/(kW·h),respectively;the cold WHTC,hot WHTC,and weighted N2O specific emissions are 0.222,0.218,and 0.219 g/(kW·h),respectively.After optimizing the volume allocation of the dual SCR system,both NOx and N2O emissions are lower.
Keywords：dual SCR systemclose-coupled SCRvolume matchingNOx emissionN2O emission
Publication Date：2025-09-30
Online Publishing Date：2026-05-22(First online date of this platform, not the publication date of the document)
Pages：8( 19-26 )