Authors
C.S. Sluder,
J.M. Storey,
S.A. Lewis, Sr., and
Linda A. Lewis
Publication
SAE Paper 2005-01-1858, SAE 2005 World Congress
Abstract
Urea-SCR systems are potentially a highly-effective means of
NOx reduction for light-duty diesel vehicles. However, use
of urea-SCR technologies at low temperatures presents unique technical
challenges. This study was undertaken to provide more knowledge about
low temperature urea decomposition and the resulting effects on SCR
performance. Data are presented for experiments using two SCR
catalysts of differing size with a light-duty diesel engine. Analyses
of the NOx reduction efficiency, NH3 storage
phenomena, and unregulated emissions are shown. Over production of
NO2 by the oxidation catalyst is demonstrated to be
problematic at 25,000 hr-1 space velocity for a range of
temperatures. This leads to production of N2O by both SCR
catalysts that is higher when urea is injected than when NH3
is injected. |
