맵 기반 제어 알고리즘 Urea 분사시스템을 장착한 승용디젤자동차의 배출가스 성능 특성

Abstract

The selective catalytic reduction(SCR) system is a highly-effective aftertreatment device for NOx reduction of diesel engines. Generally, the ammonia(NH₃) was generated from reaction mechanism of urea solution in the SCR system using the liquid urea as the reductant. Therefore, the precise urea dosing control is a very important key factor for reducing NOx and NH₃ slip in the SCR system. This paper discussed about emission characteristics of diesel passenger car with urea dosing system of map-based control algorithm. In the map-based control algorithm of this study, the urea injection was determined by mass flow rate of exhaust gas based on the engine rpm, torque, O₂ and NOx concentration measured by NOx sensor. Finally, this paper investigated the characteristics of NOx emission and NH₃ slip of diesel SCR exhaust system under NEDC mode by using the optimized map-based dosing control algorithm.