A Convergence Study on the Effects of NH3/NOx Ratio and Catalyst Type on the NOx Reduction by Urea-SCR System of Diesel Engine

디젤엔진의 Urea-SCR 시스템에 의한 NH3/NOx 비율 및 촉매 방식이 NOx 저감에 미치는 영향에 관한 융합연구

Yoon, Heung-Soo;Ryu, Yeon-Seung

  • Received : 2019.01.09
  • Accepted : 2019.04.20
  • Published : 2019.04.28


Diesel engines have important advantages over its gasoline counterpart including high thermal efficiency, high fuel economy and low emissions of CO, HC and $CO_2$. However, NOx reducing is more difficult on diesel engines because of the high $O_2$ concentration in the exhaust, marking general three way catalytic converter ineffective. Two method available technologies for continuous NOx reduction onboard diesel engines are Urea-SCR and LNT. The implementation of the Urea-SCR systems in design engines have made it possible for 2.5l and over engines to meet the tightened NOx emission standard of Euro-6. In this study, we investigate the characteristics of NOx reduction with respect to engine speed, load, types of catalyst and the $NH_3$/NOx ratio and present the conditions which maximize NOx reduction. Also we provide detailed experimental data on Urea-SCR which can be used for the preparation for standards beyond Euro-6.


Selective Catalytic Reduction(SCR);Ammonia($NH_3$);Cu-CHA catalysts;Cu-ZSM-5 catalysts;Euro-6


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