本研究目的為建立柴油引擎模型, 透過 ANSYS FLUENT 來模擬引擎在各個行程的現象, 包括汽缸壓力、 氣體速度分佈、 氣缸溫度及燃油汽化後之油氣質量分率。模擬所設定的初始條件及邊界條件是藉由實驗量測而得, 實驗引擎為中華重型柴油引擎並配置渦輪增壓、EGR 系統及燃油共軌系統。 模擬中所使用的燃油為純柴油 (C10H22), 在 FLUENT 設定,viscous model 採用 RNG k - epsilon, 而燃油自燃則使用 autoignitionmodel 來模擬。 模擬結果得到的流場資訊, 可用於輔助說明實驗上所觀察到的現象。 本論文也透過改變不同的引擎操作點, 如噴油正時及 EGR 開度, 來探討對於柴油引擎性能上的影響, 並與實驗進行驗證。 結果顯示, 當噴油正時提前, 會產生較高的汽缸壓力峰值, 並使燃燒相位提前。 而以 EGR 開度為操作條件時, 當 EGR 比例提高, 汽缸峰值溫度則降低。

In this study, a single cylinder diesel engine model is built via the ANSYS FLUENT solver to simulate the phenomenon during each stroke. The variables that can be observed from the CFD model include cylinder pressure, gas velocity, cylinder temperature, and mass fraction of cylinder gas components.The initial conditions and boundary conditions are set based on experimental data obtained from a turbo-charged common-rail diesel engine developed by Mitsubishi. The pure diesel (C10H22) is adopted in this simulation study. In FLUENT setup, k - epsilon is used in the viscous model, and the autoignition model is used to simulate the fuel spontaneous combustion. The flow field obtained from simulation results can be used to explain the macroscopic phenomena observed from experiment results. This research also discusses the effect of fuel injection timing on the cylinder pressure. Results show that as the fuel injection timing advances, the combustion phasing advances and the peak cylinder pressure raises. On the other hand, the effect of EGR ratio on peak cylinder temperature show that when EGR ratio is increased, the peak cylinder temperature will decrease.

[1] U. Asad and M. Zheng, “Real-time heat release analysis for model basedcontrol of diesel combustion,” SAE Paper, 2008-01-1000.
[2] C. D.Rakopoulos, D. T. Hountalas, D. C. Rakopoulos, and E. G. Giakoumis, Experimental heat release rate analysis in both chambers of an indirect injection turbocharged diesel engine at various load and speed conditions,” SAE Paper, 2005-01-0926.
[3] Harun M.I., H.K. Ng and S. Gan, “Evaluation of CFD Sub-models for In-Cylinder Light-Duty Diesel Engine Simulation,” Proceedings of ICEE 2009 3rd International Conference on Energy and Environment,7-8 December 2009, Malacca, Malaysia.
[4] K.M. Pang, H.K. Ng, S. Gan, ”Light-Duty Diesel Engine Modelling with Integrated Detailed Chemistry in 3-D CFD Study,” Proceedings of ICEE 2009 3rd International Conference on Energy and Environment, 7-8 December 2009, Malacca, Malaysia.
[5] Hu Mingjiang and Shen Chaoying, ”Research on Predicting Fuel Spray Characteristics of Diesel Engine,” 2010 International Conference on Intelligent Computation Technology and Automation.
[6] Shang Yong, Liu Fu-shui and Li Xiang-rong, “Numerical Simulation on Forced Swirl Combustion Chamber in Diesel Engine,” 2010 International Conference on Digital Manufacturing and Automation.
[7] Luo Maji, Xiang Liangshan and Li Xiong, “Numerical Simulation of the Effects of Combustion Chamber Geometry on Nonroad Diesel Engine Performance,” 978-1-4244-8036-4 (2011) IEEE.
[8] Francesco Bottone, Andreas Kronenburg, David Gosman and Andrew Marquis, ”Large Eddy Simulation of Diesel Engine In-cylinder Flow,” Flow Turbulence Combust (2012) 88:233-253.
[9] F. Payri, J. Benajes, X. Margot and A. Gil, ”CFD Modeling of the In-Cylinder Fow in Direct-Injection Diesel Engines,” Computers and Fluids 33 (2004) 995-1021.
[10] Gyeung Ho Choi, Jae Cheon Lee, Tae Yun Kwon, Chang Uk Ha, Jong Soon Lee, Yon Jong Chung, Yong Hoon Chang and Sung Bin Han, ”Combustion Characteristics of a Swirl Chamber Type Diesel Engine,” Journal of Mechanical Science and Technology 23 (2009) 3385 3392.
[11] Sage L. Kokjohn and Rolf D. Reitz, ”Investigation of the Roles of Flame Propagation, Turbulent Mixing, and Volumetric Heat Release in Conventional and Low Temperature Diesel Combustion,” Journal of Engineering for Gas Turbines and Power-Transactions of the ASME Volume: 133, 2011.
[12] Seung Hyun Yoon and Chang Sik Lee”Experimental investigation on the combustion and exhaust emission characteristics of biogas-biodiesel dual-fuel combustion in a CI engine,” Fuel Processing Technology 92 (2011) 992-1000.
[13] Michael Bunce, David Snyder, Gayatri Adi, Carrie Hall, Jeremy Koehler, Bernabe Davila ,Shankar Kumar, Phanindra Garimella, Donald Stanton and Gregory Shaver,”Optimization of soy-biodiesel combustion in a modern diesel engine,” Fuel 90(2011)2560-2570.
[14] N.R. Banapurmath ,P.G. Tewari and V.N. Gaitond, ”Experimental investigations on performance and emission characteristics of Honge oil biodiesel (HOME) operated compression ignition engine,” Renewable Energy 48 (2012) 193-201.
[15] Zhao Jinghua, Hong Wei, Li Xuejun, Xie Fangxi and Jue Li, ”Study about Effects of EGR and Injection Parameters on the Combustion and Emissions of High-pressure Common-rail Diesel Engine,” 2010 2nd International Conference on Industrial Mechatronics and Automation.
[16] L. Labecki and L.C. Ganippa, ”Effects of injection parameters and EGR on combustion and emission characteristics of rapeseed oil and its blends in diesel engines,” Fuel 98 (2012) 15-28.
[17] M. Mani, G. Nagarajan and S. Sampath, ”An experimental investigation on a DI diesel engine using waste plastic oil with exhaust gas recirculation,” Fuel 89 (2010) 1826-1832.
[18] Donghui Qi, Michael Leick, Yu Liu and Chia-fon F. Lee, ”Effect of EGR and injection timing on combustion and emission characteristics of split injection strategy DI-diesel engine fueled with biodiesel,” Fuel 90 (2011) 1884-1891.
[19] Mohammad Reza Herfatmanesh, Pin Lu, Mohammadreza Anbari Attar and Hua Zhao, ”Experimental investigation into the effects of two-stage injection on fuel injection quantity, combustion and emissions in a high-speed optical common rail diesel engine,” Fuel 109 (2013) 137-147.
[20] Gianluca D’Errico, Tommaso Lucchini and Frank Atzler, Rossella Rotondi, ”Computational Fluid Dynamics Simulation of Diesel Engines with Sophisticated Injection Strategies for In-Cylinder Pollutant Controls,” ENERGY and FUELS Volume: 26 Issue: 7 Pages: 4212-4223, 2012.
[21] Raouf Mobasheri, Zhijun Peng and Seyed Mostafa Mirsalim, ”Analysis the Effect of Advanced Injection Strategies on Engine Performance and Pollutant Emissions in a Heavy Duty DI-Diesel Engine by CFD Modeling,” International Journal of Heat and Fluid Flow Volume: 33 Issue: 1 Pages: 59-69, 2012.
[22] Kar Mun Pang,, Hoon Kiat Ng and Suyin Gan, ”Simulation of Temporal and Spatial Soot Evolution in an Automotive Diesel Engine Using the Moss-Brookes Soot Model,” Energy Conversion and Management Volume: 58 Pages: 171-184, 2012.
[23] B. Jayashankara and V. Ganesan, ”Effect of Fuel Injection Timing and Intake Pressure on the Performance of a DI Diesel Engine - A Parametric Study Using CFD,” Energy Conversion and Management Volume: 51 Issue: 10 Pages: 1835-1848, 2010.
[24] Y. Liu, Y. -T. Zhang, T. Qiu, X. Ding and Q. Xiong, ” Optimization research for a high pressure common rail diesel engine based on simulation,” International Journal of Automotive Technology, Vol. 11, No. 5, pp. 625-636 (2010).