Near-TDC Flow-Field Analysis in a High-Tumble Production Spark-Ignition Engine Using Endoscopic High-Speed Particle Image Velocimetry

2020 ◽  
Vol 14 (1) ◽  
Author(s):  
Lingzhe Rao ◽  
Dongchan Kim ◽  
Heechang Oh ◽  
Sanghoon Kook
2010 ◽  
Vol 43 (6) ◽  
pp. 1039-1047 ◽  
Author(s):  
Emily J. Berg ◽  
Jessica L. Weisman ◽  
Michael J. Oldham ◽  
Risa J. Robinson

2002 ◽  
Vol 3 (3) ◽  
pp. 139-155 ◽  
Author(s):  
Y Li ◽  
H Zhao ◽  
Z Peng ◽  
N Ladommatos

Tumble motion in the cylinder of a four-valve spark ignition (SI) engine with a production-type cylinder head was studied using cross-correlation digital particle image velocimetry (PIV). The in-cylinder flow field was measured on three planes: the vertical symmetric plane of the combustion chamber, the vertical plane through centres of the intake and exhaust valves, and a horizontal plane 12 mm below the cylinder head. Ensemble-averaged mean velocity, velocity fluctuation distribution and cyclic variation of the instantaneous velocity field were analysed. Analysis results show that the tumble vortex is formed in the early stage of the compression stroke and distorted in the late stage of the compression stroke. The tumble centre is nearly in the centre of the cylinder when the tumble forms. Then it moves gradually to the underneath of the exhaust valves as the piston moves up. It is found that the cyclic variation of the tumble motion at a tumble ratio of 0.9 is so great that the ensemble-averaged flow characteristics hardly represent any individual cycle flow behaviours. Distribution of the velocity fluctuation field is inhomogeneous during the whole compression process. As the engine speed changes the large-scale flow structure seems to remain unaffected.


Author(s):  
Andrew Eastman ◽  
Jacob Kiefer ◽  
Mark Kimber

Although not identical to the motion employed by nature’s swimmers and flyers, the simple harmonic oscillations of cantilever-like structures have been shown to provide efficient low power solutions for applications ranging from thermal management to propulsion. However, in order to quantify their true potential, the resulting flow field and corresponding thrust must be better understood. In this work, a thin, flexible cantilever is actuated via a piezoelectric patch mounted near its base and caused to vibrate in its first resonance mode in air. The flow field is experimentally measured with Particle Image Velocimetry while the thrust produced from the oscillatory motion is quantified using a high resolution scale. The trends observed in the data are captured using an oscillating Reynolds number and a clear relationship is defined between the operating parameters and the resulting thrust. Two dimensional flow fields are extracted from the x-y and y-z planes, and are primarily used to motivate future geometry and sidewall configurations that could greatly enhance the thrust capabilities of the cantilever by directing the flow downstream in a more effective manner.


2002 ◽  
Vol 33 (6) ◽  
pp. 794-800 ◽  
Author(s):  
U. Dierksheide ◽  
P. Meyer ◽  
T. Hovestadt ◽  
W. Hentschel

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