NOx Trap Catalysts and Technologies: Fundamentals and Industrial Applications
Chapter 15: Development of Combined NSR DeNOx and DeSOx Model and Application for Control Strategy Pre-calibration of a Modern Diesel Engine
Published:13 Jun 2018
L. Sharifian, C. Manetas, F. A. Lafossas, A. Mohammadi, K. Yoshida, and G. Koltsakis, in NOx Trap Catalysts and Technologies: Fundamentals and Industrial Applications, ed. L. Lietti and L. Castoldi, The Royal Society of Chemistry, 2018, ch. 15, pp. 430-466.
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NSR systems represent a cost-efficient aftertreatment system for NOx reduction of diesel engines in small passenger cars. Sulfur poisoning is one of the major challenges of NSR catalysts, since it reduces NOx storage and conversion efficiency. To release the sulfur from NSR, a desulfation strategy is applied to the catalyst by increasing catalyst temperature and oscillating between lean and rich engine operating condition. In the present work, a commercial NSR catalyst is studied. First a small-scale catalyst is investigated in synthetic gas bench and chemical mechanisms are proposed accordingly to explain NOx storage and reduction as well as sulfur storage and release in NSR. The developed mechanisms are implemented in a physico-chemical model and the reactions are calibrated according to the observed behaviour. Later the model is verified by correct prediction of a full-scale NSR performance in an engine bench with real exhaust line and under transient operation of engine. Finally, the NSR model is coupled with a virtual diesel engine platform and a real driving condition is simulated to estimate engine out emission and predict NSR efficiency to reduce tail NOx concentration. The developed modelling capability will be used to support NSR catalyst design and engine calibration optimization in model based development environment.