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CONTROL OF DIESEL ENGINE UREA SELECTIVE CATALYTIC REDUCTION SYSTEMS

Hsieh, Ming-Feng
http://rave.ohiolink.edu/etdc/view?acc_num=osu1281463739

Abstract Details

2010, Doctor of Philosophy, Ohio State University, Mechanical Engineering.
A systematic nonlinear control methodology for urea-SCR systems applicable for light-to-heavy-duty Diesel engine platforms in a variety of on-road, off-road, and marine applications is developed and experimentally validated in this dissertation. Urea selective catalytic reduction (urea-SCR) systems have been proved of being able to reduce more than 90% of Diesel engine-out NOx emissions and have been favored by the automotive industry in recent years. Urea-SCR systems utilize ammonia, converted from 32.5% aqueous urea solution (AdBlue) injected at upstream of the SCR catalyst, as the reductant for NOx reductions. Because ammonia is considered a hazardous material, urea injection should be systematically controlled to avoid undesired tailpipe ammonia slip while achieving a sufficient level of SCR NOx reduction. The novelty of the control methodology is to regulate the ammonia storage distribution along the axial direction of a SCR catalyst to a staircase profile and thus to simultaneously realize high NOx reduction efficiency and low ammonia emissions. To achieve this control objective, several relevant subjects are studied, including: 1) aftertreatment system control-oriented modeling, 2) online NOx sensor ammonia cross-sensitivity correction, 3) SCR catalyst ammonia coverage ratio estimation, as well as 4) adaptive urea dosing controller design. A unique SCR system which consists of a urea injector and two SCR catalysts connected in-series with several NOx and NH3 sensors is used for the study of the proposed urea-SCR control methodology. Such a SCR system is integrated with a state-of-the-art Diesel engine and aftertreatment system (DOC-DPF). The US06 test cycle experimental results show the proposed control methodology, in comparison to a conventional control strategy, is capable of improving the SCR NOx reduction by 63% and reducing the tailpipe ammonia slip amount by 74%. The contributions of this research to the art include: 1) A novel, efficient, and generalizable urea-SCR dosing control methodology; 2) Diesel engine-DOC-DPF NO/NO2 ratio control-oriented models and observer-based estimations; 3) SCR catalyst ammonia coverage ratio estimation methods; 4) An online correction approach for NOx sensor ammonia cross-sensitivity elimination; and 5) An improved SCR control-oriented model.
Wang Junmin, PhD (Advisor)
Chia-Hsiang Menq, PhD (Committee Member)
Giorgio Rizzoni, PhD (Committee Member)
Stephen Yurkovich, PhD (Committee Member)
205 p.
Engineering
diesel engine control modeling urea scr doc dpf aftertreatment NOx NH3

Recommended Citations

Citations

  • Hsieh, M.-F. (2010). CONTROL OF DIESEL ENGINE UREA SELECTIVE CATALYTIC REDUCTION SYSTEMS [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281463739

    APA Style (7th edition)

  • Hsieh, Ming-Feng. CONTROL OF DIESEL ENGINE UREA SELECTIVE CATALYTIC REDUCTION SYSTEMS. 2010. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1281463739.

    MLA Style (8th edition)

  • Hsieh, Ming-Feng. "CONTROL OF DIESEL ENGINE UREA SELECTIVE CATALYTIC REDUCTION SYSTEMS." Doctoral dissertation, Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1281463739

    Chicago Manual of Style (17th edition)

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This open access ETD is published by The Ohio State University and OhioLINK.