Exhaust Emissions from In-Use General Aviation Aircraft (2016) / Chapter Skim
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Pages 30-44
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From page 30... ...
30 Exhaust Emissions from In-Use General Aviation Aircraft of PM, when compared to using EDMS default emission indices. The Upper Limit Scenario deliberately introduces values much higher than the Average Scenario and would overestimate results in 97.5% of cases.
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Sensitivity Analysis on Airport Emissions 31 Figure 4-7 illustrates the differences observed in the net distributions of CO emissions per LTO. This figure is constructed by repeatedly drawing from the sample pool of emission indices until the results converge.
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32 Exhaust Emissions from In-Use General Aviation Aircraft trend. Figure 4-7 also suggests the climb-out phase of the LTO is responsible for the greatest share of emissions.
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Sensitivity Analysis on Airport Emissions 33 Figure 4-9. HC emissions burden change between the two scenarios.
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34 Exhaust Emissions from In-Use General Aviation Aircraft Figure 4-11. Partitioning of emissions burden by power state.
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Sensitivity Analysis on Airport Emissions 35 number of operations to be simulated (e.g., over 20,000 operations)
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36 C H A P T E R 5 Previous chapters have discussed the observed variability in emission indices between repeat measurements of the same engine. In doing these measurements, the research team discovered a complex landscape of conditions and variables that all affect the measured emissions from GA aircraft.
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Other Parameters Affecting Emissions 37 The lean it out whenever possible mindset was usually held by pilots with newer training, and particularly pilots operating aircraft with gauges showing the exhaust gas temperature (EGT) and cylinder head temperature (CHT)
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38 Exhaust Emissions from In-Use General Aviation Aircraft Of those data points, most belong to turbofan engines: the Garrett AiResearch, Pratt & Whitney Canada, Williams and General Electric engines. Earlier the research team showed that piston engines produce a significant amount of CO in all engine states.
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Other Parameters Affecting Emissions 39 figure, one starts to recover a curved shape to the data, with very low and very high-powered engine states operating at generally reduced conversion efficiencies of fuel carbon to oxidized carbon and intermediate engine states operating at higher conversion efficiencies. One key difference between the emissions from aviation piston engines and turbofan engines is the ratio of carbon monoxide to carbon dioxide (CO/CO2)
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40 Exhaust Emissions from In-Use General Aviation Aircraft (or named LTO mode) and greater dependence on the air-to-fuel ratio (or rich vs.
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Other Parameters Affecting Emissions 41 for the investigation on GA emissions. The aviation industry has recognized that the operating conditions within each component also need to be understood when moving between steadystate conditions.
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42 Exhaust Emissions from In-Use General Aviation Aircraft 3500 3000 2500 2000 C H 4 [p pb ]
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Other Parameters Affecting Emissions 43 with the addition of transients. Examination of these figures shows that the effect of transient emissions on the LTO burden is negligible.
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44 Exhaust Emissions from In-Use General Aviation Aircraft sampled. A change in emission indices for measurements taken at more extreme temperatures or barometric pressures would be expected.
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