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Measurement of Dry Soot and Particulate Matter from Two-Stroke and Four-Stroke Snowmobiles
Technical Paper
2010-32-0042
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Recent increases in emissions regulations within the snowmobile
industry have led to significant advancements in fuel, exhaust, and
control systems on snowmobiles. However, particulate matter is
currently an unregulated exhaust component of snowmobile engines.
The measurement of dry soot as well as particulate matter from
snowmobiles is the focus of this paper. Two industry-representative
snowmobiles were chosen for this research which included a 2006
Yamaha Nytro carbureted four-stroke and a 2009 Ski-Doo MX-Z
direct-injected two-stroke. Measurements for each snowmobile
included gaseous emissions (CO₂, CO, NOx, O₂, and THC),
particulate matter collected on quartz filters, and dry soot
measured using an AVL Micro Soot Sensor. Each snowmobile was tested
over the industry-standard five-mode emissions certification test
cycle to determine the emissions, dry soot, and particulate matter
levels from idle to wide open throttle (full-load).
The carbureted four-stroke snowmobile was factory-calibrated
rich of stoichiometric combustion to improve cold-start
performance, increase power, and provide acceptable throttle
response. The direct-injected two-stroke engine was susceptible to
some short-circuiting of raw fuel to the exhaust system. For this
reason, both snowmobiles produced relatively high levels of
hydrocarbon emissions and particulate matter compared to modern
automobile engines. The highest dry soot levels for both
snowmobiles were recorded at full load conditions with the
magnitude of the dry soot being quite similar for both vehicles. At
the lower engine speeds and loads, dry soot levels were
significantly higher for the direct-injected two-stroke engine
compared to the carbureted four-stroke engine. While the two-stroke
engine calibration was lean of stoichiometric at most operating
conditions which led to reduced hydrocarbon and soot emissions
compared to stoichiometric operation, the consumption of
lubricating oil had a direct impact on dry soot emissions and led
to higher emissions compared to the four-stroke engine.
The exhaust particulate matter was measured using an undiluted,
hot quartz filter which was weighed before and after each run to
determine particulate matter mass. The sample stream to the filter
was not diluted and the temperature was not maintained at a
specified value. Therefore, the measured particulate mass was an
estimate of dry soot and hydrocarbon emissions, as quartz filters
have an affinity for hydrocarbons. The mass flow rate of
particulate matter determined from the filters was significantly
higher than the dry soot results from the Micro Soot Sensor. The
two-stroke and four-stroke engines were both observed to have high
hydrocarbon emissions (10,000 - 30,000 ppmC1), which may have led
to the discrepancy between the dry soot concentration and PM
measurement techniques.
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Citation
Miers, S., Green, C., Meldrum, J., Lundberg, C. et al., "Measurement of Dry Soot and Particulate Matter from Two-Stroke and Four-Stroke Snowmobiles," SAE Technical Paper 2010-32-0042, 2010, https://doi.org/10.4271/2010-32-0042.Also In
References
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