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Title: HC quench layer formation in combustion processes. Final report

Technical Report ·
OSTI ID:5448755

Processes believed responsible for unburned hydrocarbon (HC) emissions in spark-ignition engines have been investigated in a joint study carried out by Ford and the University of Michigan (U-M). Two closely related experiments were performed at Ford and U-M together with an analytical study carried out at U-M. In the experimental work, combustion bombs fitted with identical turbulence generating inlet swirl systems were used to study the effect of turbulence on unburned HC emissions from wall quench and crevices. In the analytical work, a model was developed describing the turbulent wall quench layer in an engine. It also includes the cylinder wall oil-film and ring crevices as additional sources of hydrocarbons which feed into the wall layer after combustion. The results of the studies show that wall quench is not a major source of HC emissions in the bomb and that the effect of increased turbulence on the low emissions from wall quench is to reduce them further. Emissions from crevices introduced into the bomb were found to be more important than those from wall quenching. Turbulence did not greatly affect the HC emissions from the crevices. In the flow studies the gas motion generated by the inlet system on the bombs was found to approximate a solid body rotation with a decay time of 200 msec. High speed schlieren photography was used to observe the flame propagation and the filling and emptying of the crevices. The analytical model compared favorably with experimental engine data and supported the view that oil films and crevices are major sources of hydrocarbons in engine combustion.

Research Organization:
Ford Motor Co., Dearborn, MI (USA)
DOE Contract Number:
AC04-79ET15303
OSTI ID:
5448755
Report Number(s):
DOE/ET/15303-T7; ON: DE84005068
Resource Relation:
Other Information: Portions are illegible in microfiche products. Original copy available until stock is exhausted
Country of Publication:
United States
Language:
English