The Effect of Leaded and Unleaded Gasolines on Exhaust Emissions as Influenced by Combustion Chamber Deposits - (CRC Project CAPE-3-68)

Leikkanen, Henry E.; Beckman, E. W.

doi:10.4271/710843

Cited by 14 publications

(4 citation statements)

References 2 publications

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“…This indicates that the exhaust hydrocarbon concentration was about 8% higher with leaded fuel than with the same fuel without lead. Other investigators have also observed this "direct lead" effect (Leikkanen and Beckman, 1971).…”

Section: E F F E C T Of Tetraethyllead In Gasoline O N Exhaust Hydrocmentioning

confidence: 92%

Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity

Heuss¹,

Nebel²,

D'Alleva³

1974

Environ. Sci. Technol.

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Section: E F F E C T Of Tetraethyllead In Gasoline O N Exhaust Hydrocmentioning

confidence: 92%

Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity

Heuss¹,

Nebel²,

D'Alleva³

1974

Environ. Sci. Technol.

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“…The available data is conflicting, some of it suggesting a strong effect of CCD on HC emissions, while other data found no effect. Leikanen et al [11], compiling data from 18 industrial studies, reported increases between 69 and 100 % in HC emissions due to deposit build-up, both from fleet and bench engine tests, running on unleaded gasoline. A study by Valtadoros et al [12] at MIT found an increase of 75% in HC emissions due to deposit accumulation, from a Chrysler 2.2-L engine.…”

Section: -1 Backgroundmentioning

confidence: 99%

“…A variation on a CCD build-up cycle, developed by Texaco to study the effect of CCD on octane requirement increase and used at MIT [11], was used. During the deposit build-up test, the engine continuously goes through this cycle consisting of two operating conditions:…”

Section: -1-4 Deposit Build-up Cyclementioning

confidence: 99%

Combustion Chamber Deposit Effects on Hydrocarbon Emissions from a Spark-Ignition Engine

Haidar

Heywood

1997

SAE Technical Paper Series

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Data on the effect of combustion chamber deposits (CCD) on the HC emissions from spark-ignition engines has been scarce and contradictory. With more stringent emissions standards set by the EPA taking effect, quantifying the effect of CCDs on HC emissions from a modem spark-ignition engine is of significant importance. The objectives of this work can be summarized in three points: quantify the contribution of CCDs to the total engine-out HC emissions; identify the effect of combustion chamber deposits on the HC emissions from a matrix of single-component fuels; develop a model to describe the mechanism(s) by which CCDs lead to an increase to HC emissions. The engine is run for periods ranging from 100 to 25 hours, on a deposit build-up cycle. During deposit accumulation, the HC emissions are continuously measured at several operating conditions using an additized, specially-designed fuel that promotes CCD accumulation. In addition, HC emission measurements are taken using isooctane, benzene, toluene and xylene with the deposited and then clean engine.The experimental results show that CCDs contribute to about 15% of the total engine-out HC emissions from the deposit build-up fuel and from the four single-component fuels. Starting from a clean-engine level, the HC emissions increase rapidly in the first 10 hours of deposit accumulation and stabilize after about 25 hours. The deposits continue to grow well beyond the point where the HC emissions stabilize. After engine disassembly and CCD removal, the HC emissions drop back to their clean-engine levels, confirming the effect of CCDs on the HC emissions. The data shows no significant difference in the effect of CCDs on the HC emission increase among the four single-component fuels. The deposit pore size distribution is quantified using mercury porosimetry measurements. Using these measurements, it is concluded that the filling of deposit pores with fuel-air mixture at uniform pressure(deposit crevice mechanism) is the dominant mechanism. Accounting for oxidation of some of the fuel stored in the cylinder head and exhaust ports, the model overpredicts the experimental data by about 50%. Thesis Advisor John Heywood Professor, Mechanical Engineering ACKNOWLEDGEMENTS

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“…The increase due to the direct and indirect (deposit) effects of lead fuel additives on the engine-out HC emissions is believed to be small. 8 Switching back to unleaded gasoline reduced HC to 1.9 g/mi after an additional 3000 mi of driving. How much of this reduction was due to catalyst rejuvenation and how much to the elimination of the fuel-lead effects on the engine emissions cannot be determined.…”

Section: Hydrocarbonsmentioning

confidence: 99%

The Effect of Misfueling on Aldehyde and Other Auto Exhaust Emissions

Nebel

1981

Journal of the Air Pollution Control Association

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The Effect of Leaded and Unleaded Gasolines on Exhaust Emissions as Influenced by Combustion Chamber Deposits - (CRC Project CAPE-3-68)

Cited by 14 publications

References 2 publications

Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity

Effects of gasoline aromatic and lead content on exhaust hydrocarbon reactivity

Combustion Chamber Deposit Effects on Hydrocarbon Emissions from a Spark-Ignition Engine

The Effect of Misfueling on Aldehyde and Other Auto Exhaust Emissions

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