1 research outputs found
Influence of Real-World Engine Load Conditions on Nanoparticle Emissions from a DPF and SCR Equipped Heavy-Duty Diesel Engine
The experiments aimed at investigating the effect of
real-world
engine load conditions on nanoparticle emissions from a Diesel Particulate
Filter and Selective Catalytic Reduction after-treatment system (DPF-SCR)
equipped heavy-duty diesel engine. The results showed the emission
of nucleation mode particles in the size range of 6–15 nm at
conditions with high exhaust temperatures. A direct result of higher
exhaust temperatures (over 380 °C) contributing to higher concentration
of nucleation mode nanoparticles is presented in this study. The action
of an SCR catalyst with urea injection was found to increase the particle
number count by over an order of magnitude in comparison to DPF out
particle concentrations. Engine operations resulting in exhaust temperatures
below 380 °C did not contribute to significant nucleation mode
nanoparticle concentrations. The study further suggests the fact that
SCR-equipped engines operating within the Not-To-Exceed (NTE) zone
over a critical exhaust temperature and under favorable ambient dilution
conditions could contribute to high nanoparticle concentrations to
the environment. Also, some of the high temperature modes resulted
in DPF out accumulation mode (between 50 and 200 nm) particle concentrations
an order of magnitude greater than typical background PM concentrations.
This leads to the conclusion that sustained NTE operation could trigger
high temperature passive regeneration which in turn would result in
lower filtration efficiencies of the DPF that further contributes
to the increased solid fraction of the PM number count