This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Experimental Study of NO x Reduction by Passive Ammonia-SCR for Stoichiometric SIDI Engines
Technical Paper
2011-01-0307
ISSN: 0148-7191, e-ISSN: 2688-3627
Annotation ability available
Sector:
Language:
English
Abstract
As vehicle fuel economy requirements continue to increase it is
becoming more challenging and expensive to simultaneously improve
fuel consumption and meet emissions regulations. The Passive
Ammonia SCR System (PASS) is a novel aftertreatment concept which
has the potential to address NOx emissions with
application to both lean SI and stoichiometric SI engines. PASS
relies on an underfloor (U/F) SCR for storage of ammonia which is
generated by the close-coupled (CC) TWCs. For lean SI engines, it
is required to operate with occasional rich pulses in order to
generate the ammonia, while for stoichiometric application ammonia
is passively generated through the toggling of air/fuel ratio. PASS
serves as an efficient and cost-effective enhancement to standard
aftertreatment systems.
For this study, the PASS concept was demonstrated first using
lab reactor results which highlight the oxygen tolerance and
temperature requirements of the SCR. It was found that ammonia-SCR
performance would be improved significantly with only a few hundred
ppm level oxygen, which is a critical requirement for
stoichiometric SI engine application. The concept was then
evaluated in the context of the aftertreatment system of a
spark-ignition direct-injection (SIDI) V8 engine running the hot
FTP cycle. The results show that it is possible to achieve
incremental fuel economy improvements while using PASS to meet
necessary emissions limits. In the specific case of the work
demonstrated here, Passive SCR was combined with SIDI-enabled
Deceleration Fuel Cut-Off (DFCO) and Lean-Idle (LI) operating
strategies to achieve a greater than 11% fuel consumption
improvement over purely stoichiometric SIDI operation. This was
accomplished while meeting Tier 2 Bin 3 emissions limits with a
lower PGM material requirement compared to a conventional SI
aftertreatment system.
Recommended Content
Authors
Topic
Citation
Guralp, O., Qi, G., Li, W., and Najt, P., "Experimental Study of NOx Reduction by Passive Ammonia-SCR for Stoichiometric SIDI Engines," SAE Technical Paper 2011-01-0307, 2011, https://doi.org/10.4271/2011-01-0307.Also In
References
- Taylor, K.C. “Automobile catalytic converters,” Catalysis Science and Technology Anderson, J.R. Boudart, M. 5 Springer-Verlag New York 1984
- Heeb, N. V. Forss, A-M Bruhlmann, S. Luscher, R. Saxer, C. J. Hug, P. “Three-way catalyst-induced formation of ammonia-velocity and acceleration dependent emission factors,” Atmospheric Environment 40 2006 5986 5997
- Heeb, N. V. Saxer, C. J. Forss, A-M. Bruhlmann, S. “Trends of NO-, NO 2 -, and NH 3 -emissions from gasoline-fueled Euro-3-to Euro-4-passenger cars,” Atmospheric Environment 42 2008 2543 2554
- Huai, T. Durbin, T. H. Waynemiller, J. Pisano, J. Sauer, C. G. Rhee, S. H. Norbeck, J. M. “Investigation of NH 3 emissions from new technology vehicles as a function of vehicle operating conditions,” Environmental Science and Technology 37 2003 4841 4847
- Huai, T. Durbin, T. D. Younglove, T. Scora, G. Barth, M. Norbeck, J. M. “Vehicle specific power approach to estimating on-road NH 3 emissions from light-duty vehicles,” Environmental Science and Technology 39 2005 9595 9600
- Schmieg, S.J. Lee, J.-H. “Evaluation of Supplier Catalyst Formulations for the Selective Catalytic Reduction of NO x with Ammonia,” SAE Technical Paper 2005-01-3881 2005 10.4271/2005-01-3881
- Li, W. Perry, K.L. Narayanaswamy, K. Kim, C.H. et al. “Passive Ammonia SCR System for Lean-Burn SIDI Engines,” SAE Int. J. Fuels Lubr. 3 1 99 106 2010 10.4271/2010-01-0366
- Eng, J. Bartholomew, C.H. “Kinetic and mechanistic study of NO x reduction by NH 3 over H-form zeolite, II. Semi-steady-state and in situ FTIR studies,” Journal of Catalysis 171 1997 27 44
- Eng, J. Bartholomew, C.H. “Kinetic and mechanistic study of NO x reduction by NH 3 over H-form zeolite, I. Kinetic and mechanistic insights into NO reaction over H-ZSM-5,” Journal of Catalysis 171 1997 14 26