四汽門SI引擎汽缸內部流場模擬與分析

四行程引擎汽缸內部的流場(紊流動能與渦漩強度)對於引擎的效率、火焰傳播速度、燃油消耗率(Brake Specific Fuel Consumption, BSFC)與油氣混合(mixture preparation)有著密切的關聯，所以本研究利用電腦數值模擬方法，即所謂的計算流體動力學方式(Computational Fluid Dynamics, CFD)建立引擎動態之數值模擬技術，針對不同的引擎參數來模擬與分析流場，以作為未來提升引擎效能之參考與設計工具，所研究的參數有進氣壓力、引擎轉速、汽門正時與升程以及汽缸頭進氣道幾何形狀等。研究結果顯示，藉由遮蔽汽缸頭進氣道入口、提升引擎進氣量與進氣流速、改變汽門正時與升程等方法可使紊流動能(Turbulence Kinetic Energy, TKE)與Swirl & Tumble ratio有效地提升。

關鍵字

計算流體力學；紊流動能；燃油消耗率

並列摘要

Because the flow field in four-stroke engine cylinde (Turbulence Kinetic Energy and Vortex) is closely related to the efficiency of the engine, flame speed, BSFC and mixture preparation, therefore, this study simulation of the flow field with different parameters(intake pressure, engine speed, valve timing and lift, and the inport geometry of cylinder head) by CFD for the reference and the design to enhance the engine performance. Results of the study, shielding cylinder head inport area, increase the amount of intake air and velocity of flow, change the valve timing and lift can enhance the turbulent kinetic energy and Swirl & Tumble Ratio effectively.

並列關鍵字

CFD ； Turbulence Kinetic Energy ； Swirl & Tumble Ratio ； BSFC

參考文獻

16.莊敏傑，2004，進氣管內控制閥對汽缸流場影響之數值研究，碩士論文，中原大學，機械工程學系，桃園。

2.Mattarelli, E., Borghi, M., Balestrazzi, D., and Fontanesi, S., 2004, The Influence of Swirl Control Strategies on the Intake Flow in Four Valve HSDI Diesel Engines, SAE paper(2004-01-0112).

3.Bari, Y. S., and Saad, I., 2013, CFD modelling of the effect of guide vane swirl and tumble device to generate better in-cylinder air flow in CI engine fuelled by biodiesel, Computers & Fluids 84, pp .262–269.

4.Bae, C. S., Lee, J. S., and Ha, J. Y., 1998, High-Frequency Ignition Characteristics in a 4-Valve SI Engine with Tumble-Swirl Flows, SAE paper(981433).

5.Lee, K., Bae, C., and Kang, K., 2007, The effects of tumble and swirl flows on flame propagation in a four-valve S.I. engine, Applied Thermal Engineering 27, 2122–2130.

國際替代計量

四汽門SI引擎汽缸內部流場模擬與分析

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