Gain-scheduling and preview control of selective catalytic reduction systems in diesel engines
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Lim, Jihoon
issued: 2022-11-30T08:00:00Z
issued: 2021
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: Diesel engines have an excellent reputation due to higher torque and better fuel efficiency compared to gasoline engines. However, as a drawback, diesel combustion generates harmful nitrogen oxides (NOx) emissions. To reduce NOx emissions, the studies for selective catalytic reduction (SCR) control systems have been conducted. The SCR control system computes an optimal amount of liquid-reductant agent such as ammonia (NH₃) or urea and injects it upstream of the SCR catalyst. Thus, NOx emissions chemically react with NH₃ in the SCR catalyst resulting in ideally harmless gas coming out of the tailpipe. However, in practice, control challenges such as nonlinearity and unmeasurable catalyst conditions cause undesirable NOx and NH₃ downstream of the SCR catalyst. This thesis makes three contributions in designing the SCR controllers overcoming the control challenges. Firstly, this thesis proposes a new approach to designing a gain-scheduling (GS) SCR controller consisting of multiple linear time-invariant H infinity controllers, each of which provides satisfactory control performance for different operating points. Secondly, this thesis presents a GS linear parameter-varying SCR controller with a theoretical guarantee of stability and performance. Finally, this thesis introduces a preview-feedback SCR controller based on state augmentation techniques using previewed NOx information with a low computational requirement. The effectiveness of the proposed controllers is validated by the simulation tests using experimentally obtained data over the non-road transient driving cycle. It is shown that the proposed controllers significantly maximize NOx conversion efficiency with low ammonia out of the tailpipe even with model parameter variation and sensor noise.
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/76599
note: Gain-scheduling and Preview Control ofSelective Catalytic Reduction Systems inDiesel EnginesbyJihoon LimA THESIS SUBMITTED IN PARTIAL FULFILLMENT OFTHE REQUIREMENTS FOR THE DEGREE OFDOCTOR OF PHILOSOPHYinThe Faculty of Graduate and Postdoctoral Studies(Mechanical Engineering)THE UNIVERSITY OF BRITISH COLUMBIA(Vancouver)November 2020© Jihoon Lim 2020The following individuals certify that they have read, and recommend to the Faculty of Graduate and Post-doctoral Studies for acceptance, the dissertation entitled:Gain-scheduling and Preview Control of Selective Catalytic Reduction Systems in Diesel Enginessubmitted by Jihoon Lim in partial fulfillment of the requirements forthe degree of Doctor of Philosophyin Mechanical EngineeringExamining Committee:Dr. Ryozo Nagamune, Mechanical EngineeringSupervisorDr. Patrick Kirchen, Mechanical EngineeringCo-SupervisorDr. Bhushan Gopaluni, Chemical and Biological EngineeringUniversity ExaminerDr. Shahriar Mirabbasi, Electrical and Computer EngineeringUniversity ExaminerAdditional Supervisory Committee Members:Dr. Clarence De Silva, Mechanical EngineeringSupervisory Committee MemberDr. Steven Rogak, Mechanical EngineeringSupervisory Committee MemberDr. Rudolf Seethaler, Mechanical EngineeringSupervisory Committee MemberiiAbstractDiesel engines have an excellent reputation due to higher torque and better fuel efficiency compared togasoline engines. However, as a drawback, diesel combustion generates harmful nitrogen oxides (NOx)emissions. To reduce NOx emissions, the studies for selective catalytic reduction (SCR) control systemshave been conducted. The SCR control system computes an optimal amount of liquid-reductant agent suchas ammonia (NH3) or urea and injects it upstream of the SCR catalyst. Thus, NOx emissions chemicallyreact with NH3 in the SCR catalyst resulting in ideally harmless gas coming out of the tailpipe. However,in practice, control challenges such as nonlinearity and unmeasurable catalyst conditions cause undesirab…
has type: Thesis/Dissertation
date issued: 2021-05
is shown at: 10.14288/1.0395035
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: Attribution-NonCommercial-NoDerivatives 4.0 International
rights URI: http://creativecommons.org/licenses/by-nc-nd/4.0/
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/76599