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Optical investigation on the ability of a cordierite substrate mixing device to combat deposits in SCR dosing systems

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posted on 22.11.2016, 15:40 by Thomas O. Lockyer, Benjamin A. Reid, Graham Hargrave, Paul D. Gaynor, Jonathan Wilson
Selective catalytic reduction (SCR) has become the mainstream approach for removing heavy-duty (HD) diesel engine NOx emissions. Highly efficient SCR systems are a key enabling technology allowing engines to be calibrated for very high NOx output with a resultant gain in fuel consumption while still maintaining NOx emissions compliance. One key to the successful implementation of high efficiency SCR at elevated engine out NOx levels is the ability to introduce significantly more AdBlue into the exhaust flow while still ensuring complete ammonia production and avoiding the formation of deposits. This paper presents a body of experimental work conducted on an exhaust test bench using optical techniques including high-speed imaging and phase Doppler interferometry (PDI), applied under representative exhaust conditions to a HD diesel engine after-treatment system with optical access inside the mixer tube. Two different sprays were used to dose AdBlue onto the mixing device. A three-hole injector and a single-hole pressure-swirl injector were characterised in ambient and heated exhaust flow conditions. A metallic two-stage mixer and an uncoated cordierite ceramic substrate mixer were compared and demonstrated the ability of the substrate mixer to reduce deposit formation at higher dosing rates inside the mixer tube when used with the correct spray type. High-speed imaging revealed the ability of the substrate to absorb injected AdBlue spray at cooler exhaust temperatures. However, using the incorrect spray can lead to liquid saturation inside the substrate channels, which is detrimental due to the formation of deposits on the rear face of the substrate.

History

School

  • Mechanical, Electrical and Manufacturing Engineering

Published in

Society of Automotive Engineers

Citation

LOCKYER, T.O. ...et al., 2015. Optical investigation on the ability of a cordierite substrate mixing device to combat deposits in SCR dosing systems. SAE Technical Papers 2015-01-1039, 2015, doi:10.4271/2015-01-1039.

Publisher

© SAE International

Version

VoR (Version of Record)

Publication date

2015

Notes

Copyright © 2015 SAE International. This paper is posted on this site with permission from SAE International, and is for viewing only. Further use or distribution of this paper is not permitted without permission from SAE.

ISSN

0148-7191

Language

en

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