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Pollutant formation in a gaseous-fuelled, direct injection engine McTaggart-Cowan, Gordon Patrick
Abstract
Heavy-duty natural gas engines offer air pollution and energy diversity benefits. However, current homogeneous-charge lean-burn engines suffer from impaired efficiency and high unburned fuel emissions. Direct injection offers the potential of diesel-like efficiencies, but requires further research. To improve understanding of the combustion process and pollutant formation mechanisms in a pilot-ignited, direct injection of natural gas engine with intake charge dilution, the effects of enhanced gaseous jet kinetic energy, gaseous fuel composition (including ethane, propane, hydrogen, and nitrogen), and filtering the recirculated gases were studied. An experimental investigation was carried out on a single-cylinder heavy-duty engine. Fuel consumption, in-cylinder performance and gaseous and particulate emissions (total mass, size distributions, and black carbon content) were measured. The results indicated that increasing the jet kinetic energy significantly reduced particulate matter (PM) emissions due to improved fuel-air mixing, especially at high load. The addition of hydrogen to the fuel reduced emissions of carbon monoxide (CO), unburned fuel (HC) and PM. The largest effects were observed at high load conditions. The addition of ethane and propane to the fuel resulted in increases in PM and CO emissions at all operating conditions tested; no effect on the combustion progression was detected. The addition of nitrogen to the fuel significantly reduced emissions of CO, PM, and HC due to enhancement of the late-cycle combustion event from increased in-cylinder turbulence. Removing PM from the recirculated gases revealed that these particles had no significant effect on the combustion event or on PM emissions. In conclusion, mixing and kinetic enhancement both reduced the gaseous fuel ignition delay. The overall combustion event was, at high load, mixing limited; the combustion rate was unaffected by fuel reactivity but was increased with turbulence enhancement. Emissions formation was found to be a result of multiple influences whose relative importance varied with operating condition. Increased mixing and lower fuel carbon content reduced P M emissions. Reductions in emissions through the addition of hydrogen and nitrogen to the fuel may offer a potential technique to offset increases in emissions due to variations in ethane and propane levels in natural gas.
Item Metadata
Title |
Pollutant formation in a gaseous-fuelled, direct injection engine
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
2006
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Description |
Heavy-duty natural gas engines offer air pollution and energy diversity benefits.
However, current homogeneous-charge lean-burn engines suffer from impaired efficiency
and high unburned fuel emissions. Direct injection offers the potential of diesel-like
efficiencies, but requires further research. To improve understanding of the combustion
process and pollutant formation mechanisms in a pilot-ignited, direct injection of natural gas
engine with intake charge dilution, the effects of enhanced gaseous jet kinetic energy,
gaseous fuel composition (including ethane, propane, hydrogen, and nitrogen), and filtering
the recirculated gases were studied.
An experimental investigation was carried out on a single-cylinder heavy-duty
engine. Fuel consumption, in-cylinder performance and gaseous and particulate emissions
(total mass, size distributions, and black carbon content) were measured. The results
indicated that increasing the jet kinetic energy significantly reduced particulate matter (PM)
emissions due to improved fuel-air mixing, especially at high load. The addition of hydrogen
to the fuel reduced emissions of carbon monoxide (CO), unburned fuel (HC) and PM. The
largest effects were observed at high load conditions. The addition of ethane and propane to
the fuel resulted in increases in PM and CO emissions at all operating conditions tested; no
effect on the combustion progression was detected. The addition of nitrogen to the fuel
significantly reduced emissions of CO, PM, and HC due to enhancement of the late-cycle
combustion event from increased in-cylinder turbulence. Removing PM from the recirculated
gases revealed that these particles had no significant effect on the combustion event or on
PM emissions.
In conclusion, mixing and kinetic enhancement both reduced the gaseous fuel ignition
delay. The overall combustion event was, at high load, mixing limited; the combustion rate
was unaffected by fuel reactivity but was increased with turbulence enhancement. Emissions
formation was found to be a result of multiple influences whose relative importance varied
with operating condition. Increased mixing and lower fuel carbon content reduced P M
emissions. Reductions in emissions through the addition of hydrogen and nitrogen to the fuel
may offer a potential technique to offset increases in emissions due to variations in ethane
and propane levels in natural gas.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-01-16
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0080746
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.