Effects of Tetraethyl Lead Concentration on Exhaust Emissions in Customer Type Vehicle Operation

Gagliardi, John; Ghannam, F. E.

doi:10.4271/690015

Cited by 18 publications

(7 citation statements)

References 6 publications

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“…This result is in excellent agreement with the results from vehicle tests for unleaded fuels as reported by Gagliardi and Ghannon (1969), and suggests that the proposed mechanisms of HC increase due to deposit layers are active under engine operating conditions. It also suggests that approximately 7-10 percent (1 10 ppm' C1'/[1000 to 1500 ppm' Cl']) of the in-cylinder HC emission from engines using unleaded fuels may arise from deposits collected on the combustion chamber walls.…”

Section: An Extension To Engine Conditionssupporting

confidence: 92%

“…The density of this deposit was not measured; however, its density should be similar to the density of deposits formed in engines operating on unleaded fuel (indolene clear) with a similar petroleum-based motor oil. From Gagliardi and Ghannon (1969), the density of a similar deposit was Downloaded by [University of Auckland Library] at 13:13 27 November 2014 measured to be 0.87 g/cc. For this density, the thickness of the deposit layer in the HSH reactor is approximately 0.0017 cm.…”

Section: Methodsmentioning

confidence: 99%

“…, I Studies in vehicles (see Gagliardi and Ghannon, 1969) conducted during deposit accumulation tests indicate that the hydrocarbon emission from engine deposiis generated during operation with unleaded fuels is approximately 100 ppm 'CI' and with leaded fuels is approximately 900 ppm TI'. To compare our results to these engine test results and to show that the dissolution of fuel into the deposit layer is a plausible mechanism of HC emission increase under engine operating conditions requires the scaling of data in Figure 3 to those conditions encountered under engine operation.…”

Section: An Extension To Engine Conditionsmentioning

confidence: 99%

“…One documented source of H C emission increase is the accumulation of carbonaceous deposits along combustion chamber walls (see Hagen and Holiday, 1962;Gagliardi and Ghannon, 1969;Gagliardi, 1967). However, the mechanisms which control the deposit HC increase are not well understood.…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Engine Deposit Layers on Hydrocarbon Emissions from Closed Vessel Combustion

Adamczyk

Kach

1986

Combustion Science and Technology

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The effects of engine deposit layers on the product gas emissions from combustion bombs manufactured from engine combustion chambers were studied for various fuel-deposit systems. Nine fuels (methane, ethane, propane, n-butane, n-pentane, n-hexane, benzene, n-heptane and iso-octane) were tested in combination with two ill-sit11 engine deposit layers-one thin (0.0017 cm) and one thick (-0.05-0.1 cm). Gas samples from the reactors were analyzed by gas chromatography.For the thin deposit, the results show that the principal exhaust effluent is unburnt fuel. Additionally, as the solubility of the fuel is increased, the H C emission increases in direct proportion to the change in relative solubility and the absolute HC level can be estimated from the deposit composition and estimated fuel solubility.For the thick deposit, the results show that the principal exhaust effluent is also unburnt fuel, that the exhaust H C level increases with fuel solubility and that a small fraction of the H C emission may arise from the porous structure of the deposit. Additionally, however, they show that the exhaust H C emission decreases as the loading and sampling times of the reactor are reduced and is proportional to the square root of the loading time, suggesting that time-dependent loading processes will be important at the proportionally shorter time scales of engines even at the elevated temperature found in typical engine combustion chambers.

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Section: An Extension To Engine Conditionssupporting

confidence: 92%

Section: Methodsmentioning

confidence: 99%

Section: An Extension To Engine Conditionsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The Effect of Engine Deposit Layers on Hydrocarbon Emissions from Closed Vessel Combustion

Adamczyk

Kach

1986

Combustion Science and Technology

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“…Carbonaceous deposit layers on the combustion chamber wall and piston crown have been documented to increase HC emissions in several studies [34] [35] [36]. Adamcyk and Kach [37] studied the mechanism by introducing in-situ engine deposit layers in a combustion bomb fueled by normal paraffin fuels.…”

Section: Poor Mixture Preparationmentioning

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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Fuel Economy and Emissions

Kummer

1984

Fuel Economy

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Effects of Tetraethyl Lead Concentration on Exhaust Emissions in Customer Type Vehicle Operation

Cited by 18 publications

References 6 publications

The Effect of Engine Deposit Layers on Hydrocarbon Emissions from Closed Vessel Combustion

The Effect of Engine Deposit Layers on Hydrocarbon Emissions from Closed Vessel Combustion

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

Fuel Economy and Emissions

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