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Flow Vector Measurements at the Scavenging Ports in a Fired Two-Stroke Engine
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Abstract
The flow vector variations at the transfer port exit in a small two-stroke engine under firing condition were investigated experimentally. A fiber LDV system was used to measure the two-dimensional velocities near the cylinder to obtain the scavenging flow vector. The scavenging flow vector variations at different engine speeds were discussed, and the relation between its vector behavior and the pressure differences between the exhaust pipe and the crankcase was examined. The measurement results show that the velocity profiles at the scavenging port were not uniform and to obtain the representative velocity at the port exit was impossible. But the major features of the scavenging flow can be understood from the pressure difference between the exhaust pipe and the crankcase. The start timing of the scavenging flow was delayed due to the residual gas and high pressure in the cylinder when the scavenging port was opened. The vector had almost constant flowing angle and reached first peak, and the vector rotated due to the reverse flow from the cylinder to the crankcase which caused the negative peak. The second velocity peak was caused by the pressure wave reflection from the exhaust pipe. Finally, the gas leakage between the piston pin and cylinder was found.
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Citation
Ikeda, Y., Ohhira, T., Takahashi, T., and Nakajima, T., "Flow Vector Measurements at the Scavenging Ports in a Fired Two-Stroke Engine," SAE Technical Paper 920420, 1992, https://doi.org/10.4271/920420.Also In
References
- Smyth J. G. et al. “Motored and Steady Flow Boundary Conditions Applied to the Prediction of Scavenging Flow in a Loop Scavenged Two-Stroke Cycle Engine,” SAE Paper No. 900800 1990
- Smyth J. G. et al. “Steady Flow Analysis of the Scavenging Process in a Two-Stroke Cycle Engine - A Theoretical and Experimental Study,” SAE Paper No. 881267 1988
- Sweenely M. E. G. et al. “Computational Fluid Dynamics Applied to Two-Stroke Engine Scavenging,” SAE Paper No. 851519 1985
- Uzkan T. et al. “Analytically Predicted Improvements in the Scavenging and Trapping Efficiency of Two-Cycle Engine,” SAE Paper No. 880108 1988
- Diwakar R. “Three-Dimensional Modeling of the In-Cylinder Gas Exchange Process in a Uniflow-Scavenged Two-Stroke Engine,” SAE Paper No. 870596 1987
- Carpenter M. H. Ramos J. I. “Modeling of a Gasoline-Injected Two-Stroke Cycle Engine,” SAE Paper No. 860167 1986
- Befrui et al. “Multi-Dimensional Calculation of the Flow Processes in a Loop-Scavenged Two-Stroke Cycle Engine,” SAE Paper No. 890841 1989
- Epstein P.H. Reitz R.D. Foster D.E. “Computations of a Two-Stroke Engine Cylinder and Port Scavenging Flow,” SAE Paper No. 910672
- Sher E. et al. “Predicting of the Gas Exchange Performance in a Two-Stroke Cycle Engine,” SAE Paper No. 850086 1985
- Sher E. et al. “A Simple and Realistic Model for the Scavenging Process in a Crankcase-Scavenged Two-Stroke Cycle Engine,” IMechE 205 129 137 1991
- Sher E. “Scavenging the Two-Stroke Engine,” Prog. Energy Combust. Sic. 16 1990 95
- Sher E. “A New Practical Model for the Scavenging Process in a Two-Stroke Engine,” SAE Paper No. 850085 1985
- Ikeda Y. et al. “Scavenging Flow Measurements in a Motored Two-Stroke Engine by Fiber LDV,” SAE Paper No. 910669 1991
- Ikeda Y. et al. “Scavenging Flow Measurements in a Fired Two-Stroke Engine by Fiber LDV,” SAE Paper No. 910670
- Ikeda Y. et al. “A Compact Fiber LDV with a Perforated Beam Expander,” Measurements Science and Technology 1 3 1990 260
- Ikeda Y. et al. “Simultaneous Measurement of Velocity and Pressure in A Two-Stroke Engine,” COMODIA 90 1990 481 487