Square-root unscented Kalman filter for ammonia coverage ratio and input ammonia estimations in diesel-engine urea-SCR system

Shichun Yang; Song Feng; Kangfeng Sun; Shuai Wang; Yaoguang Cao

doi:10.1016/j.isatra.2019.06.025

Square-root unscented Kalman filter for ammonia coverage ratio and input ammonia estimations in diesel-engine urea-SCR system

ISA Trans. 2020 Jan:96:299-308. doi: 10.1016/j.isatra.2019.06.025. Epub 2019 Jun 27.

Authors

Shichun Yang¹, Song Feng², Kangfeng Sun³, Shuai Wang⁴, Yaoguang Cao⁵

Affiliations

¹ School of Transportation Science and Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing 100191, China. Electronic address: yangshichun@buaa.edu.cn.
² School of Transportation Science and Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing 100191, China. Electronic address: fengsong@buaa.du.cn.
³ SAIC VOLKSWAGENAUTOMOTIVE COMPANY LIMITED, No. 63 Luopu Road, Jiading District, Shanghai 201805, China. Electronic address: sunkf1993@163.com.
⁴ School of Computer Science and Technology, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing 100191, China. Electronic address: wangshuai@buaa.edu.cn.
⁵ School of Transportation Science and Engineering, Beihang University, No. 37 Xueyuan Road, Haidian District, Beijing 100191, China. Electronic address: caoyaoguang@buaa.edu.cn.

PMID: 31326078
DOI: 10.1016/j.isatra.2019.06.025

Abstract

The selective catalytic reduction (SCR) is a resultful technical approach to diminish the NOx emission in the diesel-engine exhaust. And closed-loop control is of vital importance for SCR system to realize high NOx reduction and low ammonia tailpipe leakage. The input ammonia and the ammonia coverage ratio are two crucial parameters, but the cost of a sensor measuring the former is high, and the latter cannot be obtained by the sensor directly. Thus an observer based on square-root unscented Kalman filter is designed to estimate the two parameters. Meanwhile, a three-state model is established to mathematically describe the SCR system. The simulation results show that the observer can make an outstanding estimation on the state variables, and it shows strong robustness to the external interference.

Keywords: Ammonia coverage ratio; Input ammonia; Selective catalytic reduction; Square-root unscented Kalman filter.