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Flow near a spark plug is important for early flame kernel development (EFKD) and combustion efficiency. Velocity data have been measured by a laser Doppler velocimetry (LDV) for three different positions near a spark plug within a ported single cylinder optical spark ignition (SI) engine with a heart-shaped combustion chamber and a compression ratio of 8.9. LDV measurements have been performed under the wide-open motored conditions with an engine speed of 1,000 rpm conditions and maximum data collection rates of 22 kHz per channel. This work examines the mean and turbulence flow fields as interpreted through ensemble, cyclic, discrete wavelet transformation (DWT) analysis and the energy cascade as analyzed through continuous wavelet transformation (CWT) for flows near a spark plug.

Principal formulation effects on oil-fluoroelastomer compatibility in European specification tests are reviewed, and detailed surface analysis of elastomer samples after exposure to oil reported. The mechanism of fluoroelastomer degradation has been investigated and found to be based on fluorine depletion of a thin surface layer by dispersant additives. Compatibility is determined by both the oil and the detailed composition of the elastomer. Correlations with field performance have not been published for current European elastomer tests. Failing oils have demonstrated satisfactory performance in field trials. Oil preageing affects seal compatibility, but probably differently for gasoline and diesel engine lubricants.