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The Effect of Fuel Composition Including Aromatics Content on Emissions From a Range of Heavy-Duty Diesel Engines
Technical Paper
CECEF03
Sector:
Language:
English
Abstract
The influence of fuel properties and chemical composition on
regulated diesel particulate emissions during operation of the
European R49 13-mode cycle has been examined. Four multi-cylinder
engines were tested to produce broadly applicable conclusions.
Since fuel properties are usually strongly correlated, making
extraction of the effects of individual properties difficult, this
study used three fuel sets having a wide range of properties and in
which the correlations between certain key properties were
broken.
The contribution of fuel sulphur to particulate emissions as
sulphate and associated water was confirmed to depend linearly on
the fuel sulphur content, with engine dependent Fuel Sulphur
Conversion Ratios of 1 to 2%.
The influence of fuel density on particulate emissions was found
to be strongly dependent on (and predictable from) the particulate
load range characteristics of individual engines. For purposes of
comparing fuels, constant torque operation was confirmed to
compensate for fuel density differences except in engines with
complex timing management systems.
After fuel sulphur and density effects are accounted for, there
remain residual fuel quality effects on particulate emissions that
are consistent with a linear dependence on cetane number and are
engine dependent in magnitude.
Particulate emissions from all the engines are fully explained
by a model that includes fuel sulphur content, density and cetane
number. Inclusion of fuel aromatics content in the model was found
to be unnecessary although the possibility of an aromatics
influence cannot be completely ruled out.
The effects of changes in specific fuel properties on
particulate emissions are quantified and presented as fractions of
the Euro-1 emissions limit.