Optimized NH3 Storage Control for Next Generation Urea-SCR System

Haga, Hisao; Kojima, Hiroyuki; Fukushi, Naoko; Ohya, Naoki; Mito, Takuya

doi:10.4271/2015-01-1024

Cited by 11 publications

(4 citation statements)

References 14 publications

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“…The unreacted NH3 is stored in the catalyst through adsorption and the stored ammonia is either further reacted with NOx and oxidized with O2 or desorbs from the surface. The potential adsorption, desorption, oxidation and NOx conversion capability of the SCR catalyst to the ammonia depends on temperature, surface area and catalyst loading (Haga et al 2015).…”

Section: Nh 3 -Scr Operation Mechanismmentioning

confidence: 99%

“…control techniques typically involve either a feedforward open-loop control or feedback closed-loop control or combination of both architecture to improve the overall SCR performance(Haga et al 2015;Chavannavar 2014). As described byHaga et al, the open-loop control technique which are considered as the conventional method in SCR control uses variables obtained from model based state estimation generally summarized in table lookups or maps which are defined either during offline (requiring calibration time) or even online (realtime learning/adaptive) basis.…”

mentioning

confidence: 99%

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Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Pradhan

Thiruvengadam

et al. 2017

SAE Int. J. Engines

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Development of an Ammonia Reduction After-treatment Systems for Stoichiometric Natural Gas Engines Saroj Pradhan Three-way catalyst (TWC) equipped stoichiometric natural gas vehicles have proven to be an effective alternative fuel strategy that shows significant low NOx emissions characteristics. However, recent studies have shown the TWC activity to contribute to elevated levels of tailpipe ammonia (NH3) emissions. Although a non-regulated pollutant, ammonia is a potent precursor to ambient secondary PM formation. Ammonia is an inevitable byproduct of fuel rich operation that results in lowest NOx slip through the TWC after-treatment system. The main objective of the study is to develop a passive Ammonia Reduction Catalyst (passive-ARC) based NH3 reduction strategy that results in an overall reduction of ammonia as well as NOx emissions. The study investigated the characteristics of Fe-based and Cu-based zeolites SCR catalysts in storage and desorption of ammonia at high exhaust temperature conditions, that are typical of stoichiometric natural gas engines. Continuous measurements of NOx and NH3 before and after the SCR systems were conducted using a Fourier Transform Infrared Spectrometry (FTIR) gas analyzer. Results of the investigation showed that both, the

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Section: Nh 3 -Scr Operation Mechanismmentioning

confidence: 99%

mentioning

confidence: 99%

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Pradhan

Thiruvengadam

et al. 2017

SAE Int. J. Engines

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show abstract

“…There are few reports of investigation of the dynamic characteristics of SCR ammonia storage and the relevant control strategies under the engine transient process. 18–20…”

Section: Introductionmentioning

confidence: 99%

Urea injection control strategy in urea-selective catalytic reduction for heavy-duty diesel engine under transient process

Liu

Sun

et al. 2019

International Journal of Engine Research

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A urea injection control strategy for urea-selective catalytic reduction under a transient process is investigated on a heavy-duty diesel engine test bench in this study. The aim is to improve NO x conversion efficiency and reduce ammonia slip. With the selective catalytic reduction system as the research object, an open thermodynamic conservation system is established. The conservation relationship in the process of urea injection, NO x reduction reaction, ammonia storage, and ammonia slip is investigated. The ideal target ammonia storage area and the ammonia storage characteristics during the transient process are studied. The ammonia storage area and boundary, which change with the transient temperature, are established. Correction of real-time ammonia injection is further deduced from the boundary of the area. The world harmonized transient cycle test cycle result showed that compared to feed-forward control, the NO x conversion efficiency increased by 16% and the NH3 slip decreased by 75% when using the proposed real-time ammonia storage-management control method.

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“…29,30 In addition, several research studies have focused on optimum control of the NH 3 storage on SCR catalysts. [31][32][33] It is well known that the deNO x efficiency and the NH 3 slip out of the SCR catalyst are dependent on the amount of NH 3 stored on the catalyst. 34 Fourth, thermal management technologies to achieve a high SCR efficiency are rapidly progressing with the help of improved motoring and sensor techniques.…”

Section: Introductionmentioning

confidence: 99%

Simulation study on improving the selective catalytic reduction efficiency by using the temperature rise in a non-road transient cycle

Wang¹,

Kim²,

Ahn³

2016

Proceedings of the Institution of Mechanical Engineers, Part D:

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In this study, the transient nitrogen oxide reduction performance of a urea selective catalytic reduction system installed on a non-road diesel engine was tested on an engine dynamometer bench over a scheduled non-road transient cycle mode. Based on the measurement results, the characteristics of the transient selective catalytic reduction behaviours of nitrogen oxide reduction were evaluated. Also, in this study, the effects of several thermal management strategies for improving the selective catalytic reduction efficiency was investigated by transient selective catalytic reduction simulations. The kinetic parameters of the current simulation code for selective catalytic reduction were calibrated and validated by comparison with the measurement data. As a result of this study, it was found that a thermal management strategy utilizing a partial temperature rise in the transient time domain can be an efficient approach for improving the transient selective catalytic reduction efficiency, in comparison with the temperature rise over the entire cycle period. Furthermore, this study can provide some guideline data for the magnitude and the duration of the temperature rise required to obtain the target selective catalytic reduction efficiency over the non-road transient cycle mode. In the last part of this study, the impact of the variation in the space velocity on the transient selective catalytic reduction efficiency was assessed using transient selective catalytic reduction simulations.

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Optimized NH3 Storage Control for Next Generation Urea-SCR System

Cited by 11 publications

References 14 publications

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Development of an Ammonia Reduction Aftertreatment Systems for Stoichiometric Natural Gas Engines

Urea injection control strategy in urea-selective catalytic reduction for heavy-duty diesel engine under transient process

Simulation study on improving the selective catalytic reduction efficiency by using the temperature rise in a non-road transient cycle

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