Development of Urea-SCR System for Heavy-Duty Commercial Vehicles

Hirata, Kiminobu; Masaki, Nobuhiko; Ueno, Hiroki; Akagawa, Hisashi

doi:10.4271/2005-01-1860

Cited by 59 publications

(21 citation statements)

References 3 publications

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“…The injection of urea-water sprays (UWS) within selective catalytic reduction (SCR) systems is a common strategy for NO x abatement [7,2,14]. For the de-NO x process to be effective, it is however mandatory that the urea-water spray vaporise in a very short amount of time.…”

Section: Introductionmentioning

confidence: 99%

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Postrioti

Brizi

Ungaro

et al. 2015

Fuel

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Section: Introductionmentioning

confidence: 99%

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

Postrioti

Brizi

Ungaro

et al. 2015

Fuel

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“…At the beginning, the SCR aftertreatment systems were implemented into heavy-duty vehicles [1]. Recently introduced NOx limitations [2] forced their application into passenger cars.…”

Section: Introductionmentioning

confidence: 99%

LIF/Mie Droplet Sizing of Water Sprays from SCR System Injector using Structured Illumination

Kapusta

2017

Proceedings ILASS–Europe 2017. 28th Conference on Liquid Atomization and Spray Systems

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Recent trends in SCR (Selective Catalytic Reduction) systems development increase requirements for UWS (Urea Water Solution) injection. Close-coupled SCR system designs decrease the distance available for water evaporation and urea decomposition. Due to that, much effort is put into static mixing elements design improvement and injection process enhancement. So far, most experimental studies on UWS spray formation were based on Mie scattering visualization using global illumination and shadowgraphy imaging. High speed imaging of Mie signal with global illumination allows to determine global spray parameters such as penetration and angle but does not give information on droplet sizes. Droplet size determination, due to relatively large droplets generated by SCR injectors, can be done with Mie scattering or backlight imaging methods. Then the visualized area becomes narrowed since high magnification is required. Determination of droplet size distribution across whole spray in such arrangement requires number of measurements. LIF/Mie (Laser Induced Fluorescence/Mie scattering) technique provides an attractive alternative for rapid determination of droplet size distribution across the whole spray. This method however suffers from multiple scattering effects which might affect droplet size distribution results even in relatively dilute sprays. In this study, LIF/Mie ratio distribution across sprays from commercial automotive injector for SCR systems was determined by simultaneous LIF and Mie detection using structured illumination. Moreover, the results were compared with conventional LIF/Mie imaging. Nd:YAG pulse laser was used as a light source. Second harmonic beam of 532 nm was used to illuminate the sprays. Instead of UWS pure water doped with Eosin Y was used. The results showed that conventional images exhibited much stronger background signal. Moreover, the conventional imaging was sensitive to reflections from experimental setup elements, specifically reflections from LIF camera filter. These two observations prove the importance of using SLIPI for LIF/Mie droplets sizing in sprays for SCR systems. At the same time the obtained results showed that under certain conditions (no accidental reflections in the background) conventional imaging provides similar LIF/Mie ratio as structured illumination. The results showed that the LIF/Mie ratio remains unchanged over the spray cloud. This suggests that SMD remains unchanged as well. The slight increase of LIF/Mie ratio far from the injector outlet could be caused by absence of small droplets due to lower momentum and thus lower penetration distance. This assumption however should be verified with PIV measurement.

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“…As it was expected, the pre-catalyst had the effect of increasing the NO 2 concentration in the exhaust stream, The NO 2 production during both the ESC and ETC testing are presented in Figure 26 and Figure 27. Previous studies have shown that increased NO 2 level have the effect of improving the low temperature performance of the reduction catalyst system by using the so called "fast SCR reaction" [1,2]. The effect of increased NO 2 production for overall system efficiency in this experiment is discussed later on.…”

Section: Influence Of Pre-oxidation Catalystmentioning

confidence: 82%

“…fast SCR reaction, which is especially important at low temperatures[1,2]. Depending on system configuration, the DOC also plays an important role in passive and active regeneration of the downstream PM Metalit or DPF.…”

mentioning

confidence: 99%

Innovative Substrate Technology for High Performance Heavy Duty Truck SCR Catalyst Systems

Rice¹,

Krämer²,

Mueller-Haas³

et al. 2007

SAE Technical Paper Series

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Diesel engine emissions regulations throughout the world have changed dramatically over the last 20 years, with the most stringent phase for medium/heavy duty being implemented starting 2007 -2010. The general perception is, that combination systems including PM reduction devices and NOx aftertreatment, likely SCR will be applied, hence significant additional emissions equipment will need to be added to a diesel engine. The consequences of this will be increased space for packaging and increased cost, to meet the demanding regulations.Traditional substrate technology, while developing extensively for gasoline engines by use of higher cell densities has limitations when applied to CI diesel engines. New developments in substrate and coating technology now enable considerable improvement in the efficiency and packaging space needed to meet certain limit values. A novel approach combining a continuously operating PM-reduction with advanced "turbulent" SCR-catalyst in a special system configuration has been investigated in an engine cell program with a HDDE, demonstrating the capability to approach US 2010 emission limits with an extremely compact and cost effective design. PRE-DEVELOPMENT

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Development of Urea-SCR System for Heavy-Duty Commercial Vehicles

Cited by 59 publications

References 3 publications

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

A methodology to investigate the behaviour of urea-water sprays in high temperature air flow for SCR de-NOxapplications

LIF/Mie Droplet Sizing of Water Sprays from SCR System Injector using Structured Illumination

Innovative Substrate Technology for High Performance Heavy Duty Truck SCR Catalyst Systems

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