An Investigation into the Effects of Fuel Properties and Engine Load on UHC and CO Emissions from a Light-Duty Optical Diesel Engine Operating in a Partially Premixed Combustion Regime 2010-01-1470
The behavior of the engine-out UHC and CO emissions from a
light-duty diesel optical engine operating at two PPCI conditions
was investigated for fifteen different fuels, including diesel
fuels, biofuel blends, n-heptane-iso-octane mixtures, and
n-cetane-HMN mixtures. The two highly dilute (9-10% O₂) early
direct injection PPCI conditions included a low speed (1500 RPM)
and load (3.0 bar IMEP) case~where the UHC and CO have been found
to stem from overly-lean fuel-air mixtures~and a condition with a
relatively higher speed (2000 RPM) and load (6.0 bar IMEP)~where
globally richer mixtures may lead to different sources of UHC and
CO. The main objectives of this work were to explore the general
behavior of the UHC and CO emissions from early-injection PPCI
combustion and to gain an understanding of how fuel properties and
engine load affect the engine-out emissions.
The UHC and CO emissions from an emissions certification diesel
fuel and several soy- and palm-based biofuel blends were found to
partially collapse when plotted as a function of the premixed burn
duration for the low speed and load condition. Significant
reductions in both UHC and CO were observed with the biofuel
blends. The engine-out UHC and CO emissions and premixed burn
duration, which directly correlates with the magnitude of the peak
heat-release, were shown to depend on three general parameters: (1)
the injection timing, which controls the targeting and the initial
thermodynamic state of the ambient gases; (2) the mixing time
between the fuel and ambient gases during the ignition delay
period; and (3) the premixed combustion phasing, which controls the
temperature, pressure, and mixture state during premixed
combustion. In order to investigate the effects of ignition quality
and volatility in greater detail, a controlled parametric study
involving nine different fuels was conducted. The fuels were
selected to provide an orthogonal fuel matrix in which ignition
quality and volatility were varied independently. The advancement
of the combustion phasing for fuels with higher ignition quality
was found to significantly decrease the UHC and CO emissions, while
fuel volatility was determined to have a much smaller effect on the
engine-out emissions. The emissions from the higher speed and load
condition were found to be mainly dependent on the injection timing
and were less sensitive to fuel type. This is consistent with
previous studies that have attributed the behavior of the UHC and
CO emissions at higher loads to bulk mixing processes controlled by
the targeting of the injected fuel spray.
Citation: Petersen, B., Ekoto, I., and Miles, P., "An Investigation into the Effects of Fuel Properties and Engine Load on UHC and CO Emissions from a Light-Duty Optical Diesel Engine Operating in a Partially Premixed Combustion Regime," SAE Int. J. Engines 3(2):38-55, 2010, https://doi.org/10.4271/2010-01-1470. Download Citation
Author(s):
Ben R. Petersen, Isaac W. Ekoto, Paul C. Miles
Affiliated:
Sandia National Laboratories
Pages: 18
Event:
International Powertrains, Fuels & Lubricants Meeting
ISSN:
1946-3936
e-ISSN:
1946-3944
Also in:
SAE International Journal of Engines-V119-3, SAE International Journal of Engines-V119-3EJ
Related Topics:
Carbon monoxide
Diesel / compression ignition engines
Diesel fuels
Emissions certification
Fuel injection
Combustion and combustion processes
Production control
Emissions
Biofuels
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