The Piston Crevice Volume Effect on Exhaust Hydrocarbon Emission

Wentworth, J. T.

doi:10.1080/00102207108952475

Cited by 86 publications

(7 citation statements)

References 2 publications

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“…This work and the work of others [10][11][12][13][14][15] point very strongly to other causes of hydrocarbon emissions than laminar end-wall or side-wall quenching by cooled inert or radical destroying surfaces. Crevices may be a likely source of these emissions because of the rapid rate of heat transfer to the cooled surface which would occur in a crevice and because of possible restrictions on diffu- sion rates out of the crevice.…”

Section: Comparison With Other Experimental and Numerical Resultsmentioning

confidence: 55%

“…However, three other possible sources of hydrocarbon emissions have been identified by various laboratories. It has been shown that by reducing or eliminating crevices in a combustion bomb [12] or an engine [13], the unburned hydrocarbons can be reduced significantly. An oil film on the surface of a combustion bomb has also been identified as a source of residual hydrocarbons [14]; this phenomenon has been investigated by mathematical modeling [15].…”

Section: Introductionmentioning

confidence: 99%

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Combutational studies of end-wall flame quenching at low pressure: The effects of heterogeneous radical recombination and crevices

Sloane

Schoene

1983

Combustion and Flame

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A computational study of the effect of heterogeneous radical destruction and crevices on end-wall flame quenching in a lean CH4-O2-Ar mixture at low pressure has been performed. The unsteady conservation edlaations for a chemically reacting multicomponent gas have been solved with the commercially available partial differential equation solver package PDEPACK. Heterogeneous radical destruction at a cooled surface was found to have a minor effect on flame quenching compared to homogeneous destruction in the cooled flame gases near the surface. These results are in qualitative agreement with experiments performed in a side-wall geometry. Cooled crevices, however, had a much greater effect on the postquench oxidation of the fuel. Whereas the fuel layer left after quenching near a fiat wall burns up more rapidly as the pressure is increased, unburned fuel left in a crevice after quenching burns up more slowly as the pressure is increased. This reaffirms the potential importance of crevices as sources of unburned hydrocarbons in an engine. [4], CH 4 [4], methane-ethane mixtures [5], CO [6], and H 2 [6]. Potential applications for these calculations are numerous and are well described in a recent review [3]. We have begun to develop a code to perform these calculations because of their usefulness for conducting computer experiments on such combustion phenomena as flame quenching, propagation, inhibition, ignition, and pollutant formation and destruction.

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Section: Comparison With Other Experimental and Numerical Resultsmentioning

confidence: 55%

Section: Introductionmentioning

confidence: 99%

Combutational studies of end-wall flame quenching at low pressure: The effects of heterogeneous radical recombination and crevices

Sloane

Schoene

1983

Combustion and Flame

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“…(1983) showed that the piston crevice contributed 80 percent of the H C emissions due to all crevices. Wentworth's (1968) experiments with a sealed ring-orifice system showed that the HC emissions decreased by 20 to 40 percent with an 86 percent decrease in the piston top-land volume (calculated at ambient temperature). Boam et a/.…”

Section: Introductionmentioning

confidence: 97%

Oxidation of the Piston Crevice Hydrocarbon During the Expansion Process in a Spark Ignition Engine

Min

Cheng

1995

Combustion Science and Technology

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ABSTRAm-Engine-out H C emissions were measured in SI engine experiments in which the piston tooland crevice size waschaneed svstemalicallv. For a warmed-uoeneine. the H C emissions were found l o be -, .-.modestly sensitive to the piston crevice size-a 10% change in size results in approximately a 2% change in H C emissions. This low sensitivity is explained in terms of a crevice H C diKusion/oxidation model in the expansion process. When the piston crevice is sufficienlly small, however, the model shows that the H C emissions have a one-to-one correspondence with the crevice size.

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“…Reconsideration of an experiment conducted by Wentworth (1971) seems apropos. Wentworth found that by sedulously trying to eliminate the crevice at the piston crown, he could reduce unburned H C emissions from a conventional (production) engine cylinder by very roughly two-thirds.…”

Section: Suggestions For Further Studiesmentioning

confidence: 98%

A Note on Unburned Hydrocarbon Emissions from Automotive Engines

Fendell¹,

Fink²,

Feldman³

1983

Combustion Science and Technology

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A careful treatment of a n unsteady one-dimensional laminar model of the interaction of a propagating premixed fuel-lean flame with a cooled wall is undertaken. For the reciprocatingpiston-type automotive-engine context of interest, expansional cooling of the power stroke, and thermal nonuniformity in the burned gas owing to nonisobaric combustion. are included; nevertheless, nearly complere oxidation of residual near-wall hydrocarbons prior to blowdown is confirmed. Measurement of a significant peak at blowdown for hydrocarbon content of the cylinder exhaust under heavy-load operation, once explained in terms of head-wall-quench-layer content, now seems puzzling, and the alternative crevice-content explanation appears forced. Suggestions for further experimental and theoretical investigations concerning piston-crevice contributions to unburned. hydrocarbon emissions, and their reduction, are set forth.

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The Piston Crevice Volume Effect on Exhaust Hydrocarbon Emission

Cited by 86 publications

References 2 publications

Combutational studies of end-wall flame quenching at low pressure: The effects of heterogeneous radical recombination and crevices

Combutational studies of end-wall flame quenching at low pressure: The effects of heterogeneous radical recombination and crevices

Oxidation of the Piston Crevice Hydrocarbon During the Expansion Process in a Spark Ignition Engine

A Note on Unburned Hydrocarbon Emissions from Automotive Engines

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