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301.
Recent declines in carpooling among American commuters are analyzed using data derived from the US Census of Population, the Nationwide Personal Transportation Study, and the American Home Survey. The most important factors associated with recent declines in carpooling to and from work in the US include increasing household vehicle availability, falling real marginal fuel costs, and higher average educational attainments among commuters. Age, sex, family income, household lifecycle characteristics, urban form, racial diversity and relative poverty appear to have had smaller effects on observed changes in carpooling for the work trip. 相似文献
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A cycle-resolved analysis system was designed with the specified measurement instruments to investigate the characteristics
of combustion stability in a mild gasoline hybrid powertrain. A Fast Response Flame Ionization Detector (FFID), cylinder pressure
transducer and engine torque transducer were used to observe both the engine-out THC emissions and engine performance during
a brief moment of engine restart. This research aimed to improve combustion stability and was performed by varying the battery
State Of Charge (SOC), injection duration and ignition timing. The results indicate that engine combustion tends to be more
stable with longer fuel injection durations and advanced ignition timing, while the effect of the battery SOC is negligible.
Also, peculiar differences in the catalyst conversion efficiency at the front and rear of the catalyst during engine restart
and deceleration were revealed, with the degree of HC oxidation being the suspected cause. This study not only analyzed the
engine control and engine-out total hydrocarbon (THC) emission characteristics, but also implemented control strategies that
allowed for combustion stability during engine stop and restart operation. 相似文献
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