臺灣博碩士論文加值系統

燃料由噴嘴間歇地噴入火花點火引擎進氣閥附近，當未汽化的燃料液滴進入燃燒室內，因空燃比的分佈不均而造成非均質的混合油氣(heterogeneous mixture)，對於改善引擎冷啟動性與提升稀薄燃燒有著密不可分的關係。若能夠確實的瞭解汽缸內燃料液滴粒徑的變化及分佈進而瞭解燃料混合油氣的形成過程，有助於改善引擎的性能及抑制排氣污染。
本文首先以燃料液滴直徑測定為主，進行實驗來確定燃燒室內燃料液滴的蒸發過程。燃料藉由噴射方式供油，以光學系統利用Mie散射理論進行液滴粒徑的量測，分析在燃燒室內不同位置燃料液滴的粒徑變化及分佈，並探討燃料液滴在不同轉速及噴射壓力下的蒸發現象，以期能瞭解液滴蒸發及油氣形成的關係。
在模擬方面，利用單一液滴蒸發假設，在溫度和壓力不斷改變的汽缸內以近似穩態蒸發模式，在純物性推演及應用經驗蒸發係數的基礎下，模擬引擎燃燒室內燃料液滴粒徑在進氣及壓縮衝程的變化。
綜合實驗與模擬分析結果，確實瞭解燃燒室內混合油氣的形成過程中燃料液滴粒徑在不同的轉速及燃料噴射壓力下，與曲軸角度的變化關係，可提供引擎設計之良好的參考。

The fuel droplet diameter measurements by Mie scattering in the combustion chamber of a spark ignition engine may clarify the mixture formation process in the engine cylinder. Liquid fuel was injected intermittently into the air flow through an intake port. The theoretical and empirical simulations of fuel n-Heptane and iso-Octane estimated the fuel droplet diameter during intake and compression processes.


The droplet evaporation rate is inversely proportional to engine speeds at constant intake pressure and temperature in a fixed crank angle history. The dependence of a fuel droplet diameter on the injection pressures was weak. Therefore, the measurements of fuel droplets in combustion chamber by Mie light scattering and empirical and theoretical simulation during intake and compression process are available for improving engine efficiency and decreasing the exhaust pollutants emission.

摘要i
英文摘要ii
目錄iii
圖目錄vi
表目錄xii
符號說明xiii

第一章、前言1
1.1研究動機1
1.2文獻回顧1
1.3研究方向3

第二章、燃料的液滴粒徑量測理論4
2.1光散射理論的發展4
2.2光散射理論4
2.3光散射強度與粒徑參數之關係10
2.4Mie散射理論之近似解12
2.5 平均液滴粒徑的統計方法14

第三章、液滴粒徑的量測及實驗設備15
3.1引擎規格及實驗設備15
3.2燃料供給系統18
3.3光學量測系統與校正22
3.4實驗步驟32
3.4.1光學系統校正32
3.4.2實驗前準備32
3.4.3實驗進行33
3.5異辛烷與正庚烷的液滴起始粒徑與平均粒徑的比較34
第四章、燃料液滴蒸發之理論分析36
4.1數值計算式36
4.2物性常數之推演40
4.3利用經驗液滴蒸發係數模擬45

第五章、結果與討論46
5.1引擎轉速對燃料液滴蒸發過程的影響47
5.2燃料噴射壓力對液滴蒸發過程的影響56
5.3 燃燒室內液滴量測位置對液滴蒸發過程的影響64
5.4 引擎轉速對正庚烷液滴蒸發過程的影響70
5.5 引擎轉速對正庚烷蒸發常數(Ke)的影響72

第六章、結論74
參考文獻76
附錄一、液滴校正曲線圖

【1】Nakajima, Y., Saito, T., Takagi, Y., Katoh, K. and Iijima, T.: "The Influence of Fuel Characteristics on Vaporization in the SI Engine Cylinder During Cranking at Low Temperature", SAE Paper 780612, 1978.【2】Quader, A. A.: "The Axially-Stratified-Charge Engine", SAE Paper 820131, pp. 479-506, 1982.【3】Peters, B. D. and Quader, A. A.: "Wetting the Appetite of Spark Ignition Engines for Lean Combustion", SAE Paper 780234, 1978.【4】Ayusawa, T., Nemoto, T., Koo, Y. and Jo, S. H.: "Relationship Between Local Air-Fuel Ratio and Combustion Characteristics in Spark Ignition Engines", SAE Paper 780147, 1978.【5】Kadota, T.: "The Application of Laser Rayleigh Scattering to the Local Mixture Strength Measurements in SI Engine During Intake Stroke", SAE Paper 872151, 1987.【6】Kadota, T., Satoh, T., Memon, M. A. and Sumida, O.: "Mixture Strength Measurements in the Combustion Chamber of Spark Ignition Engine via Rayleigh Scattering", Trans. Japan Soc. Mech. Engrs. 54-498, B(1988).【7】Kadota, T., Zhao, F. Q. and Satoh T.: "Effect of Intake Valve Configuration in the Combustion Chamber of an SI Engine", Trans. Japan Soc. Mech. Engrs., B(1988).【8】Peters, B. D.: "Fuel Droplets inside the Cylinder of an SI Engine with Axial-Stratification", SAE Paper 820132, 1982.【9】Peters, B. D.: "Laser-Video Imaging and Measurements of Fuel Droplets in an Spark Ignition Engine", Paper C81/83, Presented at the Conference on Combustion in Engineering, IME, Oxford, England, April 11-4, 1983.【10】X. Q.Liu,C.H. Wang and C.K.Low, "Simulation of Fuel Droplet Gasification in an SI Engine", Trans. ASME, J. Engng. for GAS Turbines and Power,Vol.106,pp.848-853,1984. 【11】Chung, S. S. and Kawaguchi,O.: "Evaporation Rate of Free Paraffin Hydrocarbon Droplets in a High-Temperature and High-Pressure Gas Stream", JSME International Journal Series B, Vol.38, No. 1, pp.121-128, 1995.【12】Blau, et al.: "Scattering by Individual Transparent Shpere ", Appl.Optics, 1970.【13】Reist, P.: 微粒導論, 渤海堂文化事業有限公司, pp.271-316, 1990.【14】清水勳, 江森康文: "液體粒子的光電測定", 日本機械學會論文集(第2部), Vol.42, No.354, (昭51-2), pp.603-615, 1976.【15】Heywood, J. B.: Internal Combustion Engine Fundamentals, McGraw-Hill Book Company, New York, 1988.【16】Kerker, M.: "The Scattering of Light and Other Electromagnetic Radiation", Academic Press, New York, 1969.【17】Beckwith, T. G., Marangoni, R. D. and Lienhard J. H.: Mechanical Measurements, Addison-Wesley Publishing Company, 1989.【18】Gerald, C. F. and Wheatley, P. O.: Applied Numerical Analysis, Addison-Wesley Publishing Company, 4th ed., pp.625-634, 1989.【19】大江修造著, 賴耿陽編譯: 物性常數推算法, 復漢出版社, pp.312-313, 1987.【20】水谷幸夫: 燃燒工學, 森北出版株式會社, pp.134-137, 1989.【21】Dean, J. A.: Lane’s Handbook of Chemistry, McGraw-Hill Book Co., 13th ed., pp.7-278~7-731, 1996.【22】Lide, D. R.: CRC Handbook of Chemistry and Physics , CRC Press Inc., 76th ed., pp.6-257, 1995-1996.【23】Kobayashi, K.: Trans. Japan Soc. Mech. Engrs. (in Japanese), Vol.15, No.52, (1949), 14.【24】Kotake, S. and Okazaki, T.: Trans. Japan Soc. Mech. Engrs. (in Japanese ), vol. 34, No. 268 (1968-12), 2191. 【25】Spalding, D. B.: Proc. 4th Symp. (Int.) on Comb., (1952), 847.【26】El-Wakil, M. M., et al.: NACA TN, 3179 (1954).【27】Picken, D. J., Soliman, H. A. and Fox, M. F.: "Inlet Manifold Requirements for Low Emissions", Automotive Engineer (London), Vol.3, No.4, pp.59-61, 1978.【28】Turns, S. R.: An Introduction to Combustion, concepts and applications, McGraw-Hill Book Co., pp.84-91 ,pp.300-315, 1996.【29】角田， 廣安， 機論， 42-356， (昭 51-4), 1216.【30】門協，寶諸， 角田， 廣島大學工學部研究報告第32卷第2 號.【31】Bird,R.B. et al., Transport Phenomena. John Wiley & Sons, New York, 1960.【32】柯明權, "汽車用多點噴射式汽油引擎燃燒室內燃料液滴蒸發之研究", 逢甲大學機械工程研究所, 碩士論文, 1995.【33】陳宏彬, "火花點火引擎燃燒室內燃料液滴蒸發之研究", 逢甲大學機械工程研究所, 碩士論文,1998.【34】吳明安, "火花點火引擎燃燒室內燃料液滴空間分佈之研究",逢甲大學機械工程研究所, 碩士論文,2001.