本研究使用實驗與計算方法於一部四閥單缸四行程250 c.c.引擎作缸內噴油流場診測。實驗部份，將供油系統改裝成電子燃油噴射系統，供油方式改為燃油缸內直噴(gasoline direct injection, GDI)，主要分析噴油嘴於進氣行程噴油時，在不同的噴油時機下所造成的油氣混合之影響。實驗部份可分為兩個部份，第一部份為分析噴油嘴之物理特性，並將所得到的開啟延遲、關閉延遲時間及噴油嘴質量流率的數據套用在模擬計算中。第二部份為缸內噴油實驗，此部份是運用高速攝影機拍攝噴油嘴於進氣行程噴油時，到壓縮行程結束，燃油液滴衍化之過程。並利用不同的噴油時機與不同點火角度找出較佳的油氣混合情況。計算模擬部分是使用商業套裝計算流體動力學(computational fluid dynamics, CFD)軟體STAR-CD探討在有、無燃油噴射的狀況下，於進氣和壓縮行程期間分析缸內氣流繞著缸徑軸上的滾轉運動以及缸內燃油噴射之噴霧流場與氣流運動交互作用後的結構與衍化，並藉由循環渦度滾轉比及SMD等量化指標，定量分析流場結構與引擎性能間的相關性。所得到的實驗與計算模擬結果顯示，噴油時機於CA = 25.2o ATDC時，液滴分佈較CA = 85.2o ATDC混合更均勻。

The fuel injection timing during intake stroke of a four-stroke motorcycle engine cylinder has been studied through experiment and computer simulation. Several factors which influence the injection timing and fuel-air mixing were obtained during experiment. The injection time delay and injector characteristics were obtained from experimental results and were used as reference in the computer simulation. Using a high speed CCD camera, instantaneous evolution of mixing of air and fuel were investigated inside the engine cylinder. The quality of air fuel mixture was compared when the fuel was injected at two different settings of crank angle namely: CA = 25.2o ATDC and CA = 85.2o ATDC. Computer simulation was aided by a CFD software STAR-CD to understand the mechanics during “no-spray” and “spray” situation inside the engine cylinder. The flow motion generated by such computer simulation was quantified by SMD and dimensionless tumble ratio. Results from experiments and computer simulations both showed that the injection done at CA = 25.2o ATDC was more homogeneous than CA = 85.2o ATDC.

[1]Mayer, H., “Air Pollution in Cities,” Atmospheric Environment, Vol. 33, October 1999, pp. 4029-4036.
[2]李進修, 王漢英, 汽機車引擎設計與分析技術, 國立清華大學出版社, 2005.
[3]Heywood, J. B., Internal Combustion Engine Fundamentals, McGraw-Hill, New York, 1988.
[4]Kent,J.C.,Mikulec,A.,Rimal,L.,Adamczyk,A.A.,Mueller,S.R.Stein,R.A.,and Warren,C.C.,“Observations on the Effects of Intake-Generated Swirl and Tumble on Combustion Duration,”SAE Trasaction, vol. 98, pp. 2042-2053, SAE892096, (1989)
[5]Omori, S., Iwachido, K., Motomochi, M., and Hirako, O., “Eddect of Intake Port Flow Pattern on the In-Cylinder Tumbling Air Flow in Muti-Valve S.I. Engines,” SAE Paper 910477, (1991)
[6]Endres, H., Neusser, H. J., and Wurms, R., “Influence of Swirl and Tumble on Economy and Emissions of Muti Valve S.I. Engine,” SAE Paper 920516, (1992)
[7]Heywood, J. B., Internal Combustion Engine Fundamentals, McGraw-Hill, New York, 1988.
[8]Heywood, J. B., “Fluid Motion within the Cylinder of Internal Combustion Engine-The 1986 Freeman Scholar Lecture.” Journal of Fluids Engineering, Transactions of the ASME, Vol. 109, No. 1, 1987, pp. 3-35.
[9]Han, Z., Reitz, R. D., “Effects of Injection Timing on Air-Fuel Mixing in a Direct-Injection Spark-Ignition Engine,” Journal of Engine, SAE Transactions-Section 3, Vol. 106, 1997, pp. 848-860, SAE 970625.
[10]Han, Z., Fan, L., and Reitz, R. D., “Multidimensional Modeling of Spray Atomization and Air-Fuel Mixing in a Direct-Injection Spark-Ignition Engine,”Journa of Engine, SAE Transactions-Section 3, Vol. 106, 1997, pp. 1423-1441, SAE 970884.
[11]Matsumura, E., Tomita, T., Takeda, K., Furuno, S., and Senda, J., “Analysis of Visualized Fuel Flow inside the Slit Nozzle of Direct Injection SI Gasoline Engine,” Journal of Engine, SAE Transactions-Section 3, Vol. 112, 2003, pp. 238-245, SAE 2003-01-0060.
[12]Tanaka, Y., Takano, T., Sami, H., Sakai, K., and Osumi, N., “Analysis on Behaviors of Swirl Nozzle Spray and Slit Nozzle Spray in Relation to DI Gasoline Combustion,” Journal of Engine, SAE Transactions-Section 3, Vol. 112, 2003, pp. 218-235, SAE 2003-01-0059.
[13]Papageorgakis, G., Assanid, D. N., “Optimizing Gaseous Fuel-Air Mixing in Direct Injection Engines Using an RNG Based k-ε Model,” Journal of Engine, SAE Transactions-Section 3, Vol. 107, 1998, pp. 82-107, SAE 980135.
[14]Tomoda, T., Sasaki, S., Sawada, D., Saito, A., and Sami, H. “Development of Direct Injection Gasoline Engine-Study of Stratified Mixture Formation,” Journal of Engine, SAE Transactions-Section 3, Vol. 106, 1997, pp. 759-766, SAE 970539.
[15]Harada, J., Tomita, T., Mizuno, H., Mashiki, Z., and Ito, Y., “Development of Direct Injection Gasoline Engine,” Journal of Engine, SAE Transactions-Section 3, Vol. 106, 1997, pp. 767-776, SAE 970540.
[16]Ohsuga, M., Shiraishi, T. Nogi, T., Nakayama, Y., and Sukegawa, Y., “Mixture Preparation for Direct-Injection SI Engine,” Journal of Engine, SAE Transactions-Section 3, Vol. 106, 1997, pp. 794-801, SAE 970542.
[17]Rotondi, R., Bella G.,“Gasoline direct injection spray simulation ,
”International Journal of Thermal sciences 45 (2006) 168-179
[18]Arcoumanis, C., Godwin, S. N., and Kim, J. W., “Effect of Tumble Strength on Combustion and Exhaust Emissions in a Single-Cylinder, Four-Valve, Spark-Ignition Engine,” Journal of Engines, SAE Transactions-Section 3, Vol. 107, 1998, pp. 1547-1562, SAE 981044.
[19]Iwamoto, Y., Noma, K., Nakayama, O., Yamauchi, T., and Ando, H., “Development of Gasoline Direct Injection Engine,” Journal of Engines, SAE Transactions-Section 3, Vol. 106, 1997, pp. 777-793, SAE 970541.
[20]邱彥凱, 二閥單缸機車引擎的缸內直噴技術發展, 國立台灣科技大學機械工程技術研究所碩士論文, 2008。
[21]Auriemma, M., Caputo, G., Corcione, F. E., and Valentino, G., “Fluid-Dynamic Analysis of the Intake System for a HDDI Diesel Engine by STAR-CD Code and LDA Technique,” Journal of Engines, SAE Transactions-Section 3, Vol. 112, 2003, pp. 21-28, SAE 2003-01-0002.
[22]Nonaka, Y., Horikawa, A., Nonaka, Y., Hirokawa, M., and Noda, T., “Gas Flow Simulation and Visualization in Cylinder of Motor-Cycle Engine,” Journal of Engines, SAE Transactions-Section 3, Vol. 113, 2004, pp. 1710-1714, SAE 2004-32-0004.
[23]Versteeg, H. K. and Malalasekera, W., An Introduction to Computational Fluid Dynamics-The Finite Volume Method, Wiley, New York, 1995.
[24]Dodge, L. G., 1996 "Fuel preparatio nrequirements for direct-injected spark ignitionengines," SAE Technical Paper, No. 962015.
[25]劉加陽, 四行程二閥內燃機引擎的氣流特性, 國立台灣科技大學機械工程技術研究所碩士論文, 2007。
[26]黃志偉, 使用PIV技術診測進氣埠受調制之引擎缸內流場, 國立台灣科技大學機械工程技術研究所碩士論文, 2003。
[27]楊賀順, 平頂與凹面活塞四閥四行程引擎的缸內流場滾轉運動與紊流衍化：PIV量測技術的開發與應用, 國立台灣科技大學機械工程技術研究所碩士論文, 2004。
[28]林冠旭, 增強內燃機缸內氣流滾轉運動的方法與診測:計算模擬與PIV實驗量測, 國立台灣科技大學機械工程技術研究所碩士論文, 2006。