Effect of fuel structure on emissions from a spark-ignited engine. 2. Naphthene and aromatic fuels

Kaiser, E. W.; Siegl, Walter O.; Cotton, David F.; Anderson, Richard W.

doi:10.1021/es00032a014

Cited by 101 publications

(55 citation statements)

References 8 publications

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“…These results are certainly very interesting. However, the observations and conclusions drawn in their paper are in large measure identical (with certain exceptions) to those presented earlier in a series of publications from the Ford Motor Co., [2][3][4][5][6] which have not been cited by the authors. For this reason, I believe it is important to discuss briefly the Ford results and to compare them to this Journal paper.…”

supporting

confidence: 78%

“…They state that "1-hexene is emitted from … cyclohexane fuels." Our experiments showed no generation (< 0.5 ppmC) of 1-hexene when our engine was fueled with cyclohexane, nor would we expect it based on the reasonable assumption that hydrogen abstraction from the cyclohexane molecule by a free radical is the initial step in cyclohexane consumption in an engine (see data and discussion on p 1585 of Kaiser et al 1992 3 ). Neither my co-authors nor I wish to diminish the value of the work of Zervas et al, which corroborates most of our previous research.…”

mentioning

confidence: 70%

“…(2) In Kaiser et al 1992, 3 the abstract states, "Engineout hydrocarbon emissions for the napthenes contain 12% 1,3-butadiene and 5% benzene. This represents the first observation of substantial benzene emission from a non-aromatic fuel.…”

mentioning

confidence: 99%

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Journal of the Air & Waste Management Association

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confidence: 78%

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2000

Journal of the Air & Waste Management Association

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“…The one dimensional ring-pack mixed lubrication model of Tian et.al. [80] showed that the oil film thickness is less than 1.5 micrometer. Combined with the experimentally determined diffusivity data, the model results show that the oil layer was fully penetrated at all of the operating conditions tested.…”

Section: Discussionmentioning

confidence: 99%

“…[79] there is a loss of a portion of very low vapor pressure species during the sampling process and GC analysis, and this loss increases rapidly once a threshold point in vapor pressure has been passed. In a previous experiment [80] using single component fuels, the total HC determined from GC was compared to that of a conventional hot FID. The agreement was within 10% for all fuels except xylene, which represented the highest boiling point of the tested fuels, and for which the GC recovery was 75% relative to the hot FID.…”

Section: Speciated Emissionsmentioning

confidence: 99%

Contribution of Oil Layer Mechanism to the Hydrocarbon Emissions from Spark-Ignition Engines

Linna

Målberg

Bennett³

et al. 1997

SAE Technical Paper Series

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One mechanism by which some fuel may escape the main combustion process in spark-ignition engines and be exhausted as unburned hydrocarbons is by absorption in the lubricating oil on the cylinder liner. The importance of this mechanism is, however, uncertain. Modeling studies suggest that the process can take place within an engine cycle, and that the amount of fuel absorbed in the oil layer is significant. Investigations in combustion bombs, and engines operated without lubricant indicate that this contribution is substantial. However, several researchers have reported no significant effect, when using combinations of fuels and oils with very different solubility characteristics.This study comprise the results from several experiments and modeling efforts. A ten component synthetic fuel, and different lubricants formulated to study the effect of base stock and viscosity were tested. The predicted variation in oil layer thickness caused by viscosity differences, were of the order of 20-40%. Steady state engine tests were carried out at three different coolant temperatures using a single cylinder engine with the combustion chamber of a production engine. A piston with reduced ring-pack crevices, and a cylinder head gasket designed to line up flush with the liner, were used to minimize the combustion chamber crevice volumes, and thus focus on HC derived from the oil layer mechanism. In addition to total HC, speciated engine-out emissions were recorded for the cold operating condition.Critical unknown physical parameters for the fuel components and lubricants were experimentally determined. Head space gas chromatography was used to measure solubilities, and Nuclear Magnetic Resonance was used to establish diffusion rates. Numerical modeling was employed to estimate the oil layer thickness, and the absorption rates for the individual fuel components. The estimated differences in absorption rate or "source strength" for the different lubricants, as caused primarily by different oil layer thickness, and fuel-oil solubility were of the order of 20%. The speciated emissions showed some sensitivity to oil layer thickness at low load and speed, with thicker oil layers producing more of the heavy, i.e. more soluble, fuel components. At higher loads and speeds speciated emissions showed very little to none sensitivity to oil layer thickness. For total engine-out HC, i.e. fuel and non-fuel HC, no significant effect of oil layer thickness, or calculated source strength, was observed at any of the operating conditions, contrary to what would be expected if fuel-oil absorption was contributing significantly to engine-out HC. Thus these results do not support oil layer mechanism as a significant source of unburnt hydrocarbons in the tested engine.

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Emissions of C₆–C₈ aromatic compounds in the United States: Constraints from tall tower and aircraft measurements

Millet

Baasandorj

et al. 2015

JGR Atmospheres

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We present two full years of continuous C 6 -C 8 aromatic compound measurements by PTR-MS at the KCMP tall tower (Minnesota, US) and employ GEOS-Chem nested grid simulations in a Bayesian inversion to interpret the data in terms of new constraints on US aromatic emissions. Based on the tall tower data, we find that the RETRO inventory (year-2000) overestimates US C 6 -C 8 aromatic emissions by factors of 2.0-4.5 during 2010-2011, likely due in part to post-2000 reductions. Likewise, our implementation of the US EPA's NEI08 overestimates the toluene flux by threefold, reflecting an inventory bias in non-road emissions plus uncertainties associated with species lumping. Our annual top-down emission estimates for benzene and C 8 aromatics agree with the NEI08 bottom-up values, as does the inferred contribution from non-road sources. However, the NEI08 appears to underestimate on-road emissions of these compounds by twofold during the warm season. The implied aromatic sources upwind of North America are more than double the prior estimates, suggesting a substantial underestimate of East Asian emissions, or large increases there since 2000. Long-range transport exerts an important influence on ambient benzene over the US: on average 43% of its wintertime abundance in the US Upper Midwest is due to sources outside North America. Independent aircraft measurements show that the inventory biases found here for C 6 -C 8 aromatics also apply to other parts of the US, with notable exceptions for toluene in California and Houston, Texas. Our best estimates of year-2011 contiguous US emissions are 206 (benzene), 408 (toluene), and 822 (C 8 aromatics) GgC.

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Effect of fuel structure on emissions from a spark-ignited engine. 2. Naphthene and aromatic fuels

Cited by 101 publications

References 8 publications

Letters To The Editor

Letters To The Editor

Contribution of Oil Layer Mechanism to the Hydrocarbon Emissions from Spark-Ignition Engines

Emissions of C₆–C₈ aromatic compounds in the United States: Constraints from tall tower and aircraft measurements

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Effect of fuel structure on emissions from a spark-ignited engine. 2. Naphthene and aromatic fuels

Cited by 101 publications

References 8 publications

Letters To The Editor

Letters To The Editor

Contribution of Oil Layer Mechanism to the Hydrocarbon Emissions from Spark-Ignition Engines

Emissions of C6–C8 aromatic compounds in the United States: Constraints from tall tower and aircraft measurements

Contact Info

Product

Resources

About

Emissions of C₆–C₈ aromatic compounds in the United States: Constraints from tall tower and aircraft measurements