因內燃機的排氣是空氣污染的主要來源之一，所以近來國內外學者投入對於引擎減污技術及替代性燃料的研究。生質柴油能具有回收廢棄物與再生能源的雙重效益。然而提高生質柴油添加比例會降低霧化能力而產生差的低溫啟動性，因此引入均質壓燃方式利於點燃油氣混合物，可降低黑煙及NOX濃度，但會提高CO與HC濃度。故本研究安裝汽油噴射系統與控制系統於直噴式柴油引擎進氣口處，且以汽油噴入引擎進氣口與空氣混合，形成均勻混合物後進入氣缸。柴油引擎在不同負荷與轉速下運轉，以生質柴油與柴油混合物當主燃料，改變生質柴油混合比、汽油之能量分配比、進氣溫度及廢氣再循環比例比進行實驗，量取氣缸內燃氣壓力一曲柄角數據、進氣溫度、排氣溫度、空氣流率、排氣流率、與排氣污染濃度（CO/HC/CO2, NOX, Smoke及PAHs）等，進行BTE、熱釋放率及排氣污染濃度分析。
使用KIVA3V-RELEASE2為程式主體，藉由加入程式的詳細化學反應進行數值運算，分析不同輔助燃料比例對均質壓燃柴油引擎的影響，並將數值模擬與實驗結果相互比較，進而探討實驗之可靠性。
實驗結果指出使用汽油輔助燃料可有效降低CO2、NOX與Smoke的汙染排放，在排放的PAHs方面，可以降低Total-PAHs、LMW-PAHs、MW-PAHs、毒性當量(BaPeq)和三種高致癌性(BbF+BaP+DBA)濃度；混合生質柴油可以降低CO、HC與Smoke等的汙染排放，在排放的PAHs方面，對Total-PAHs、LMW-PAHs、HMW-PAHs、毒性當量(BaPeq)與三種高致癌性(BbF+BaP+DBA)濃度有降低的效果。使用B15搭配30 %汽油輔助燃料，能較D100(石化柴油)減低31.17 %之Smoke、16.67 %之HC、1.75 %之NOX，而CO會增加25 %，CO2增加2.82 %；但是可大幅降低排放之總PAHs 58.02 %、LMW-PAHs 62.67 %、HMW-PAHs 40.83 %、BaPeq 49.24 %與(BbF+BaP+DBA) 69.56 %，雖然MMW-PAHs會增加2.66 %，整體而言可以降低引擎汙染的排放。

Because the exhaust emissions from an internal combustion engine are a major source of air pollution, domestic and foreign scholars recently has been studying on the emission decrease technologies and alternative fuels in the engine. Biodiesel can be made with the dual benefits of recycling waste and renewable energy. However, the increase of biodiesel ratio will reduce atomization and poor low temperature start, so the introduction of the HCCI (homogeneous charge compression ignition) conducive to igniting the fuel mixture can reduce the smoke and NOX concentrations, but increase the CO and HC concentrations. This study installs a gasoline injection system and control system at the intake of direct injection diesel engine, and gasoline is injected to mix with air forming a homogeneous mixture with directly injecting biodiesel and diesel mixture in the cylinder. The cylinder gas pressure crank angle data, intake air temperature, exhaust gas temperature, air flow rate, exhaust flow rate, and exhaust pollution concentrations (CO/HC/CO2, NOX, Smoke, and PAHs) are measured for diesel engine operating under fixed load, the intake air temperature, exhaust gas recirculation (EGR) ratio, and different speeds when the biodiesel mixture ratio and the energy distribution of the gasoline are changed. The BTE, heat release rate, and the concentrations of exhaust pollution are then analyzed.
In addition, this study applies KIVA3V-RELEASE2 adding detailed chemical reaction for numerical computation, and analysis effect of homogeneous charge compression ignition diesel engine by using auxiliary fuel. Comparing experimental results with numerical results can confirm the reliability of the experiment.
Use of gasoline as auxiliary fuel can effectively reduce CO2, NOX, and Smoke emissions. For the PAHs emissions, it can reduce Total-PAHs, LMW-PAHs, HMW-PAHs, toxicity equivalence quantity (BaPeq) and three kinds of carcinogenic potential (BbF + BaP + DBA). Petroleum diesel blend of biodiesel can reduce CO, HC, and Smoke emissions; in PAHs emissions, it has reduced effect for total PAHs, LMW-PAHs, HMW-PAHs, BaPeq and (BbF + BaP + DBA). Using B15 with 30 % gasoline auxiliary fuel can reduce 31.17 % for Smoke, 16.67 % for HC, 1.75 % for NOX, but increase 25 % for CO and 2.82 % for CO2 compared with the D100 (petroleum diesel). In the PAHs emissions, it can significantly reduce 58.02 % for total-PAHs, 62.67 % for LMW-PAHs, 40.83 % for HMW-PAHs, 49.24 % for BaPeq and 69.56 % for (BbF + BaP + DBA) but increase 2.66 % for MMW-PAHs. Overall, the use of gasoline can reduce engine pollution emissions.

[1] 政策財團法人國家政策研究基金會 http://old.npf.org.tw/ research-a5-96-3.htm
[2] S. Park, H. Kim, B. Choi, “Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel （BD20）”, Journal of Mechanical Science and Technology 23: 2555-2564, 2009.
[3] H. Aydin, H. Bayindir,“An experimental study on the exhaust emissions of a partially loaded compressed ignition engine fueled with biodiesel derived from cottonseed oil”, Energy sources, part A 32:1076–1085, 2010.
[4] K. Sureshkumar, R. Velraj, R. Ganesan,“Performance and exhaust emission characteristics of a CI engine fueled with pongamia pinnata methyl ester (PPME) and its blends with diesel”, Renewable Energy 33: 2294–2302, 2008.
[5] D.S. Kim, M.Y. Kim, C.S. Lee “Improved emission characteristics of HCCI engine by various premixed fuels and cooled EGR,” Fuel,; 85: 695-704, 2006.
[6] H.W. Wu, R.H Wang, D.J Ou, Y.C. Chen, and T.Y. Chen, “Reduction of smoke and nitrogen oxides of a partial HCCI engine using premixed gasoline and ethanol with air,” Applied Energy, 88: 3822-3890, 2011.
[7] S. Onishi, S.H. JO, K. Shoda, P.D. Jo, and S. Kato, “Active Themo-Atmosphere Combustion(ATAC)-A New Combustion Process for Internal Combustion Engines”, SAE 790501,1979.
[8] M. Christensen, A. Hultqvist, and B. Johansson, “Demonstrating the Multi Fuel Capability of a Homogeneous Charge Compression Ignition Engine with Variable Compression Ratio” SAE 1999-01-3679, 1999.
[9] M. Christensen and B. Johansson, “Influence of Mixture Quality on Homogeneous Charge Compression Ignition.” SAE982454, 1998.
[10] Suzuki, H., Koike, N., and Odaka, M, “Combustion Control Method of Homogeneous Charge Diesel Engines”, SAE980509, 1998.
[11] S. Park, H. Kim, B. Choi, “Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20),” Journal of Mechanical Science and Technology 23: 2555-2564, 2009.
[12] P. Pott, “Chirurgical observations: relative to the cataract, the polypus of the nose, the cancer of the scrotum, the different kinds of ruptures, and the mortification of the toes and feet,” L. Hawes, W. Clarke, and R. Collins, London, 1775.
[13] J.W. Cook, C.L Hewet and I. Hieger, “The Isolation of a Cancer-Producing Hydrocarbon from Coal Tar. Part I, II, and III.” J. Chem. Soc., pp.395-421, 1933.
[14] 陳啟聰(Q.C. Chen)，“柴油引擎以天然氣為輔助燃料之燃燒循環變異與燃燒噪音之研究”，國立成功大學機械工程研究所碩士論文，1989。
[15] T.W. Ryan III and T.J. Callahan, “Homogeneous Charge Compression Ignition of Diesel Fuel”, SAE 961160, 1996.
[16] A.W. Gray and T.W. Ryan, “Homogeneous Charge Compression Ignition (HCCI) of Diesel Fuel”, SAE971676, 1997.
[17] R. Ogink , V. Golovitchev, “Gasoline HCCI Modeling: Computer Program Combining Detailed Chemistry and Gas Exchange Processes”, SAE International Fall Fuels & Lubricants Meeting & Exhibition, September 2001, San Antonio, TX, USA.
[18] S. Kong, R.D. Reitz, M. Christensen and B. Johansson, “Modeling the Effects of Geometry-Generated Turbulence on HCCI Engine Combustion”, SAE2003 World Congress & Exhibition, March 2003, Detroit, MI, USA.
[19] S.C. Kong, “A study of natural gas/DME combustion in HCCI engines using CFD with detailed chemical kinetics”, Fuel, v 86,n 10-11, p 1483-1489, July/August, 2007.
[20] P.H. Cheng, “A Study on Homogeneous-charge Compression- Ignition Engine,” Department of Marine Engineering, National Taiwan Ocean University, Master Thesis, 2004.
[21] D.S. Kim , M.Y. Kim , and C.S. Lee, “Effect of premixed gasoline fuel on the combustion characteristics of compression ignition engine” Energy and Fuels, v 18, n 4,p1213-1219, July/August, 2004.
[22] D.S. Kim and C.S. Lee, “Improved emission characteristics of HCCI engine by various premixed fuels and cooled EGR” Fuel, v 85, n5-6, p 695-704, March/April, 2006.
[23] D.S. Kim and C.S. Lee, “Reduction of Nitric Oxides and Soot by Premixed Fuel in Partial HCCI Engine”ASME,v128,p491- 505, July, 2006.
[24] D.S. Kim, M.Y. Kim and C.S. Lee, “Combustion and emission characteristics of a partial homogeneous charge compression ignition engine when using two-stage injection” Combustion Science and Technology, v 179, n 3, p 531-551, March, 2007.
[25] S.M. Aceves, D.L. Flowers, J. Martinez-Frias, F. Espinosa-Loza, M. Christensen, B. Johansson and R.P. Hessel, “Analysis of the Effect of Geometry Generated Turbulence on HCCI Combustion By Multi- Zone Modeling”, SAE Brasil Fuels & Lubricants Meeting, Rio De Janiero, BRAZI ,May 2005.
[26] M.Y. Kim; D.S. Kim; C.S. Lee, “Reduction of Nitric Oxides and Soot by Premixed Fuel in Partial HCCI Engine,” Joural of Engineering for Gas Turbines and Power, Vol.128, 2006.
[27] X.C. Lu, Y.C Hou, L.B Ji, L.L Zu and Z. Huang, “Heat Release Analysis on Combustion and Parametric Study on Emissions of HCCI Engines Fueled with 2-Propanol/n-Heptane Blend Fuels” Energy and Fuels, v 20, n 5, p 1870-1878, September/October, 2006.
[28] W.H. Su; B. Liu; H. Wang and H.Z. Huang, “Effects of Multi- Injection Mode on Diesel Homogeneous Charge Compression Ignition Combustion,” Journal of Engineering for Gas Turbines and Power, Vol. 129, JANUARY 2007.
[29] S.H. Kook, S. Park and C.S. Bae, “Influence of Early Fuel Injection Timings on Premixing and Combustion in a Diesel Engine,” American Chemical Society, Vol. 22, No. 1, 2008.
[30] G.Y. Huang, “The Influences of Bio Diesel Fuel and Premixed Gasoline Injection Combustion on the Diesel Engine Performance and Emissions,” Department of Mechanical Engineering, National Yunlin University of Science and Technology, Master Thesis, 2006.
[31] S.W. Li, “Characterization of PAH Emissions from both Fossil- and Bio-Diesel Engines,” Department of Environmental Engineering, National Cheng Kung University, Master Thesis, 2004.
[32] Y.S. Huang, “Saving Energy and Reducing Polycyclic Aromatic Hydrocarbons Emissions from a Heavy-Duty Diesel Engine by H2/O2 Addition to the Combustion Chamber,” Institute of Environmental Engineering, National Sun Yat-sen University, Master Thesis, 2011.
[33] F.Y. Chen, “Effect of Gasoline Composition on the Emission of Polycyclic Aromatic Hydrocarbons from the Motorcycle Engine,” Institute of Chemical Engineering, Southern Taiwan University of Technology, Master Thesis, 2003.
[34] S.H. Tseng, “Characteristic of Polycyclic Aromatic Hydrocarbons Emitted from a Biodiesel Generator,” Department of Environmental Engineering and Science, National Pingtung University of Science and Technology, Master Thesis, 2009.
[35] S.Y. Yang, “Emission of Polycyclic Aromatic Hydrocarbons from a Heavy-duty Diesel Engine on Diesel Cetane Index and Total Aromatic Content,” Department of Environmental Engineering Science, Chia Nan University of Pharmacy and Science, Master Thesis, 2004.
[36] A. Dipple, “Chemical Carcinogens,” ACS Mongraph 173, C. E. Searle (Ed.). American Chemical Society, Washington, D.C. 1976.
[37] C.A. Menzie, B.B. Potocki and J. Santodonato, “Exposure to Carcinogenic PAHs in the Environment,” Environ. Sci. Technol., Vol. 26, pp. 1278-1284, 1992.
[38] United States Environmental Protection Agency Office of Solid Waste Washington, DC 20460 January 2008 http://www.epa.gov/ osw/hazard/wastemin/minimize/factshts/pahs.pdf
[39] D. Anderton and P.E. Waters, “Effect of Fuel Composition on Diesel Engine Noise and Performance”, SAE 820235, 1982.
[40] S. Henningsen, “Hydrocarbon Emissions from the Ignition-Delay Period in a Direct-Ignition Diesel Engine”, SAE 841381, 1984.
[41] T. Murayama, T. Yamada, N. Miyamoto, and T. Chikashisa, “Nature and Reduction of Cycle-to-Cycle Combustion Variation in an IDI Diesel Engine with Ethanol-Diesel Fuel Blends”, SAE 831352, 1983.
[42] F. Cruz-Peragón, F. J. Jiménez-Espadafor, J. M. Palomar, M. P. Dorado, “Influence of a combustion parametric model on the cyclic angular speed of internal combustion engines. Part I: setup for sensitivity analysis,” 2009, Energy & Fuels, 23: 2921-2929.
[43] T. Shudo, H. Suzuki, “Applicability of heat transfer equations to hydrogen combustion,” JSAE Rev., 2002, 23: 303–308.
[44] C.R. Ferguson, “Internal Combustion Engine Fundamentals: Applied Thermoscience,” John Wiley & Sons, Inc., 1986.
[45] B. Heywood, “Internal combustion engine fundamentals,” New York, U.S.A: McGraw-Hill Book Company, 1988.
[46] L.D. Cloutman, J.K. Dukowicz, J.D. Ramshaw, and A.A. Amsden, “CONCAS-SPRAY: A Computer Code for Reactive Flow with Fuel Sprays,”Los Alamos Scientific Laboratory Report, LA-9294-MS, 1982.
[47] A.A. Amsden, T.D. Butler, P.J. O’Rourke and J.D. Ramshaw, “KIVA-AComprehensive Model for 2-D and 3-D Engine Simulation,” SAE 850554, 1985.
[48] A.A. Amsden, “KIVA-3V, Release 2, Improvments to KIVA-3V,” Los Alamos National Laboratory report LA-13608-MS, May, 1999.
[49] C. Liu, “An Experimental and Analytical Investigation into the Combustion Characteristics of HCCI and Dual Fuel Engines with Pilot Injection”, Ph.D. diss., Dept. of Mechanical and Manufacturing Engineering, Calgary Univ, 2006 .
[50] Y.F. Liu and P.C. Pei, “Asymptotic Analysis on Autoignition and Explosion Limits of Hydrogen-Oxygen Mixtures in Homogeneous Systems”, International Journal of Hydrogen Energy 31(5), 639-647, 2006
[51] K. Seshadri, N. Peters and G. Paczko, “Rate-ratio asymptotic analysis of autoignition of n-heptane in laminar non-premixed flows”, Comb. & Flame Vol 146, No. 1-2, 131-141, 2006.
[52] S. Liu, J.C. Hewson, J.H. Chen, “Nonpremixed n-heptane autoignition in unsteady counterflow”, Combustion and Flame 145, pp. 730-739, 2006.
[53] C.C. Chen, “Investigation of the Characteristic and the Sources of Polycyclic Aromatic Hydrocardons in the Atmosphere,” Department of Environmental Engineering and Management, Chaoyang University of Technology, Master Thesis, 2003.
[54] http://en.wikipedia.org/wiki/Soxhlet_extractor
[55] Y.C. Lin, “Reduction of pollutant emissions and promotion of energy efficiencies on diesel engines fueled with biodiesel and emulsified diesel,” Department of Environmental Engineering, National Cheng Kung University, Ph.D. thesis, 2006