Fuel charge inhomogeneity and wall wetting contribute to abnormally high hydrocarbon emissions associated with cold and warm engine starting. In this work, a series of aldehydes with various molecular weights and boiling points were used as fluorescent tracers to study the effect of fuel volatility and engine operating conditions on the in-cylinder charge distribution. The tests were conducted in an optically accessible engine consisting of a production GM Quad-4 cylinder head and intake manifold, with an FEV systemmotor crankcase and 'Bowditch' transparent piston. Planar laser induced fluorescence was used to study the in-cylinder fuel vapor distribution and determine the presence of liquid droplets. The incident laser beam, from a tunable excimer laser operating at 308 nm, was formed into a horizontal sheet parallel to the piston surface. The fluorscence signal was detected through the transparent piston with a gated intensified CCD detector. Each fuel consisted of iso-octane, which has a boiling point near the mean boiling point of a fully formulated gasoline, and a fluorescent aldehyde dopant. The specific aldehydes were chosen for their different boiling temperatures ranging from 46 deg C to 178 deg C. Engine coolant temperature was varied to simulate hot and cold fired operation. Differences in the in-cylinder distribution of the various aldehydes indicate charge stratification based on boiling point and the presence of droplets and wall wetting late in the compression stroke for heavy species.
Fuel volatility effects on in-cylinder charge homogeneity studied with planar laser-induced fluorescence
Untersuchung der Einflüsse der Kraftstoffsflüchtigkeit auf die Homogenität der Zylinderlast mit Hilfe planarlaserinduzierter Fluoreszenz
1994
8 Seiten, 5 Bilder, 2 Tabellen, 16 Quellen
Aufsatz (Konferenz)
Englisch
British Library Conference Proceedings | 1994
|Planar Laser-Induced Fluorescence Fuel Imaging During Gas-Turbine Relight
Online Contents | 2013
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