모사 배기관내 Urea 수용액 분무 균일도 측정에 관한 연구

Abstract

Diesel engines have to meet with the severe emission regulations in terms of NOx and PM. A dramatic reduction in NOx and PM emissions could be achieved with after-treatment systems such as Lean NOx Trap (LNT) and Urea-SCR. However, the high temperatures (250 ~ 350 ℃) in the exhaust pipe affects spray behavior of the secondary injector which is used for supplying the Urea-SCR. This high temperature makes it difficult to achieve uniform distribution of the reducing agent in the manifold. If the injected agent is uniformly distributed, the emissions are dramatically decreased. This paper presents the characteristics of Urea-SCR injector for injecting in the exhaust pipe. The reducing agents were a 32.5% Urea solution. The purpose of this study was to investigate the spray characteristics of injector such as spray angle, injection quantity, penetration length and SMD. In addition, Uniformity Index(UI) is calculated from the acquired images by using image processing method to clarify the distribution of spray.