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Exhaust Emissions From a Biodiesel-Fueled Direct Injection Industrial Diesel Engine
Technical Paper
2006-05-0290
Sector:
Language:
English
Abstract
Oils derived from vegetable-derived sources have long been
considered as fuels for internal combustion engines but only
recently have they received considerable recognition as alternate
fuels for spark-ignition and compression-ignition engines. While
there has been some interest in the 1980s in vegetable oils as
diesel engine fuel, the motivation for its use subsided as the
price of petroleum diesel decreased over the years. The new
interest in biodiesel stems for the same reason as before but the
increasing demand for petroleum fuels in the world is expected to
keep interest in biodiesel fuel strong for years to come.
Soy-based methyl ester (transesterified soy oil) or soy-based
biodiesel has properties that make the fuel viable for use in
diesel engines. It has higher cetane number than diesel No 2 and
contains oxygen by as much as 12% by weight. These and other
differences in chemical and physical properties of biodiesel are
expected to influence diesel engine performance. While B20 or
biodiesel containing 20% soy methyl ester has been used in some
commercial applications higher concentrations of soy methyl ester
are uncommon. This investigation was conducted to evaluate the
effects of biodiesel, containing up to 50% soy methyl ester, in an
industrial type, naturally aspirated, DI diesel engine.
A 3-cylinder, naturally aspirated DI diesel engine was used in
the investigation. Biodiesel fuels containing up to 50% soy methyl
ester were used to fuel the engine up to its full calibrated load.
Exhaust emissions of HC, NOx and smoke were measured at constant
engine speed. The results show (a) higher concentration of
biodiesel fuel reduced maximum bmep produced by the engine, (b) the
exhaust concentration of oxides of nitrogen increased slightly as
the biodiesel content in the blend increased, and (c) smoke and
hydrocarbon emissions decreased as concentration of soy methyl
ester in the blend increased.
The small reduction in power output is related to lower energy
content of biodiesel blends while a detectable increase in oxides
of nitrogen appeared to be related to fuel properties, which may
tend to advance injection timing relative to pure diesel fuel.