In this study, a simple linear supposition method is proposed to separate the flame expansion speed and swirl motion of a flame propagating in an engine cylinder. Two series of images of flames propagating in the cylinder with/without swirl motion were taken by a high frame rate digital video camera. A small tube (4 mm ID) was installed inside the intake port to deliver the fuel/air mixture with strong swirl motion into the cylinder. An LDV was employed to measure the swirl motion during the compression stroke. Under the assumption that flame propagates spherically from the each point of the flame front, a diameter of small spherical flames can be calculated from the two consecutive images of the flame without swirl motion in the cylinder. Using the normalized swirl motion of the mixture during the compression stroke and the spherical flame diameters, the flame expansion speed and swirl ratio of combustion propagation in the engine cylinder can be obtained. This simple linear superposition method for separating the flame expansion speed and swirl motion can be utilized to understand the flow characteristics, such as swirl and turbulence, during the combustion process.

1.
Arcoumanis, C., Hu, Z., Vafidis, C., and 1990, Whitelaw, J., “Tumbling a Mechanism forTurbulence Enhancement in Spark-Ignition Engines,” SAE Paper No. 900060.
2.
Checkel, D., and Ting, S., 1993, “Turbulence Effects on Developing Turbulence Flames in a Constant Volume Combustion Chamber,” SAE Paper No. 930867.
3.
Arcoumanis, C., and Bae, C., 1993, “Visualization of Flow/Flame Interaction in a Constant-Volume Combustion Chamber,” SAE Paper No. 930868.
4.
Joo, S., and Chun, K., 1999, “Improvement of the SI Engine Idle Combustion Stability Using a Fuel/Air Mixture Injection Device,” JSAE Paper No., 9932566.
5.
Gatowski, A., and Heywood, J., 1985, “Effects of Valve-Shrouding and Squish on Combustion in a Spark-Ignition Engine,” SAE Paper No. 852093.
6.
Shen, H., Hinze, P., and Heywood, J., “A Model for Flame Initiation and Early Development in SI Engine and Its Application to Cycle-to-Cycle Variations,” SAE Paper No. 942049.
7.
Stone, C. R., Brown, A. G., and Beckwith, P., 1996, “Cycle-by-Cycle Variations in Spark Ignition Engine Combustion—Part II: Modeling of Flame Kernel Displacements as a Cause of Cycle-by-Cycle Variations,” SAE Paper No. 960613.
8.
Ma, F, Shen, H., Liu, C., Wu, D., Li, G., and Jiang, D., 1996, “The Importance and Initial Flame Kernel Center Position on the Cyclic Combustion Variations for Spark-Ignition Engine,” SAE Paper No. 961969.
9.
Blizard, N. S., and Keck J. C., 1974, “Experimental and Theoretical Investigation of Turbulent Burning Model for Internal Combustion Engines,” SAE Paper No. 740191.
10.
Tabaczynski
,
R. J.
,
Trinker
,
F. H.
, and
Shannon
,
B. A. S.
,
1980
, “
Further Refinement and Validation of a Turbulent Flame Propagation Model for Spark Ignition Engines
,”
Combust. Flame
,
39
, pp.
111
121
.
11.
Witze, P. O., and Mendes-Lopes, J. M. C., 1985, “Direct Measurement of the Turbulent Burning Velocity in a Homogeneous-Charge Engine,” SAE Paper No. 851531.
12.
Hall, M. J., Bracco, F. V., and Santavicca, D. A., 1986, “Cycle-resolved Velocity and Turbulence Measurements in an IC Engine With Combustion,” SAE Paper No. 86032.
13.
Berreta
,
G. P.
,
Rashidi
,
M.
, and
Keck
,
J. C.
,
1983
, “
Turbulent Flame Propagation and Combustion in Spark Ignition Engines
,”
Combust. Flame
,
52
, pp.
217
245
.
14.
Heywood, J. B., 1988, Internal Combustion Engine Fundamentals, McGraw-Hill, New York.
You do not currently have access to this content.