因內燃機的排氣是空氣污染的主要來源之一，故近幾十年來國內外學者大量投入引擎減污技術及替代性燃料的研究，其中由於氫氣優異之燃燒特性，結合引擎與氫能之議題受到相當大的關注，但其攜帶與儲存的問題仍有待解決。本論文係探討柴油引擎排氣廢熱回收系統與甲醇蒸氣重組器整合，探討重組器產生之富氫氣體導入直噴式柴油引擎進氣處的性能及排氣汙染特性。研究分為兩部分：第一部分是探討重組器產氫濃度之適當參數，並在該參數下調整甲醇水溶液進料量，探討產氫流量之變化。第二部分是將引擎固定轉速及不同負荷下運轉，以柴油做為主燃料，調整甲醇水溶液進料量、改變富氫氣體之流量及改變廢氣再循環比例進行實驗，使富氫氣體與空氣均勻混合後進入氣缸燃燒。量取氣缸內燃氣壓力-曲柄角數據、排氣流率、與排氣汙染濃度(NOx，Smoke、PM2.5) 等，進行制動熱效率、廢熱回收率、熱釋放率及排氣汙染濃度分析，且使用KIVA 3V-RELEASE2為程式主體，藉由修改相關副程式加入詳細化學反應進行數值運算，分析不同富氫氣體比例對柴油引擎的影響；並將數值模擬與實驗結果相互比較，進而探討實驗的可靠度。

本實驗結果顯示，重組器反應溫度會直接影響產氫量與氣體濃度。若供熱不足而造成反應溫度下降，將不利於富氫氣體之生成。控制反應溫度與S/C比在適當操作參數下時，調整甲醇水溶液進料量可獲得不同的富氫氣體產量。模擬與實驗結果皆顯示：柴油引擎添加富氫氣體，可增加預混合燃燒期之熱釋放率，配合適度的廢氣再循環比例，進而有效降低NOX、Smoke、PM2.5等排氣污染；然而，當氣缸內的壓力峰值與溫度升高時，將促使有害之NOX生成。

Exhaust emission from internal combustion engines is one of the major sources of air pollution, so the scholars at home and abroad in recent decades have put lots of effort on the pollution reducing technologies of engine and alternative fuels research. Because of the excellent combustion characteristics of hydrogen, the issue of it combined with the engine has received considerable attention. However, the carrying and storage problems of hydrogen still need to be resolved. This thesis is to explore diesel engine exhaust heat recovery system integrated with the methanol steam reforming method and discuss the performance and exhaust emission characteristics. Research is divided into two parts: the first part is to discuss the operating parameters of hydrogen-producing conditions and change feed rate of methanol-water solution under the appropriate working condition. Employing the concentration of hydrogen-rich gas and flow rate of carrier gas can obtain the hydrogen flow rate. The second part is to conduct experiments with diesel engine at different loads, and the author also adjusts the input rate of methanol water solution to control the hydrogen-rich gas production and changes the exhaust gas recirculation proportion for experiment. The inlet tank makes hydrogen-rich gas and air mix uniformly before conducting into cylinder. The cylinder gas pressure crank angle data, intake air temperature, exhaust gas temperature, air flow rate, exhaust flow rate, and exhaust pollution concentrations (NOX, Smoke, and PM2.5) are measured by changing exhaust gas recirculation (EGR) ratio and amount of hydrogen-rich gas for diesel engine operating under fixed engine speed and various loads. The BTE, heat release rate, and the concentrations of exhaust pollution are then analyzed.

In addition, this thesis applies KIVA3V-RELEASE2 adding detailed chemical reaction for numerical computation to analyze effect of using hydrogen-rich gas reformed from aqueous methanol solution. Comparison of experimental results with numerical results can confirm the reliability of the experiment.

Experimental results indicate that the reaction temperature directly influences hydrogen production. If there is insufficient supply of heat to decrease the reaction temperature, the production of hydrogen-rich gas will decrease significantly. While the temperature and S/C ratio is set up under the optimal working condition, the author changes the feed rate of the aqueous methanol solution to adjust the producing amount of hydrogen. The simulation and experimental results show that adding hydrogen-rich gas in diesel engines can increase the heat release rate under the premixed combustion phase. The appropriate proportion of exhaust gas recirculation helps reduce the exhaust pollution such as Smoke, PM2.5, and NOX. However, the higher peak pressures and temperatures in the engine cylinder will lead to harmful NOX when the hydrogen-rich gas is added.

1. Heywood B., Internal Combustion Engine fundamentals, McGraw-Hill Book Company, New York, U.S.A., 1988.
2. Park S., Kim H., Choi B., “Emission characteristics of exhaust gases and nanoparticles from a diesel engine with biodiesel-diesel blended fuel (BD20) ”, Journal of Mechanical Science and Technology, Vol. 23, pp. 2555-2564, 2009.
3. Aydin H., Bayindir H., “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,Vol.32, pp.1076–1085, 2010.
4. Sureshkumar K., Velraj R., Ganesan R., “Performance and exhaust emission characteristics of a CI engine fueled with pongamia pinnata methyl ester (PPME) and its blends with diesel”, Renewable Energy, Vol.33, pp. 2294–2302, 2008.
5. Kim D.S., Lee C.S., “Improved emission characteristics of HCCI engine by various premixed fuels and cooled EGR,” Fuel, Vol.85, pp. 695-704, 2006.
6. Wu H.W. , Wang R.H, Ou D.J., Chen Y.C., and Chen T.Y., “Reduction of smoke and nitrogen oxides of a partial HCCI engine using premixed gasoline and ethanol with air”, Applied Energy, Vol. 88, pp.3822-3890, 2011.
7. Ayhan D., “Biohydrogen For Future Engine Fuel Demands”, Springer-Verlag, London, p.93, 2009.
8.Fuhs A., Hybrid Vehicles: and the Future of Personal Transportation, Taylor & Francis Group, New York, pp.4-6, 2008.
9. Liou F.S., He L.J., Heitz P.B., “The current situation and development prospect of hydrogen fuel internal combustion engines”, Automotive Engineering, Vol. 7, pp. 621-625, 2006.
10. Chiu H.S., Chen F.L., Lu H.M., “Hydrogen production and hydrogen storage technology”, Wu-Nan Culture Enterprise, Taiwan, 2007.
11. Palo D., Dagle R., Holladay J., ”Methanol steam reforming for hydrogen production”, Chemical Rev., Vol. 107 ,pp. 3992–4021,2007
12. Shih C.S., Graphic Hydrogen, Shi Mao Publishing Ltd, Taiwan, 2009.
13. Linddström B., Pettersson L.J., “Development of a methanol fuelled reformer for fuel cell application”, J. Power Sources, Vol. 118, pp.71-78, 2003.
14. Lin H.M., “Measurement and numerical simulation of the performance of the auto-thermal type methanol reformer for fuel cells”, Master Thesis, Department of Mechanical Engineering, NCHU, 2004.
15. Suh J.S., Lee M.T., Greif R., Grigoropoulos C.P., “A study of steam methanol reforming in a microreactor”, J. Power Sources, Vol.173, pp.458-466, 2007.
16.Kim T., “Micro methanol reformer combined with a catalytic combustor for a PEM fuel cell”, Int. J. Hydrogen Energy, Vol. 34, pp.6790-6798, 2009.
17. Huang S.J., “Parametric study on the performance of methanol steam reformer with Taguchi Method”, Master Thesis, Department of Systems and Naval Mechatronic Engineering, NCKU, 2013.
18. Yi C., “Parametric study on methanol reforming to produce hydrogen with exhaust heat recovery of diesel engine”, Master Thesis, Department of Systems and Naval Mechatronic Engineering, NCKU, 2014.
19. Richards N.O., Erickson P.A., “An investigation of a stratified catalyst bed for small-scale hydrogen production from methanol autothermal reforming”, Int. J. Hydrogen Energy, Vol. 39, pp.18077-18083, 2014.
20. Tsolakis A., Megaritis A., “Catalytic exhaust gas fuel reforming for diesel engines-effects of water addition on hydrogen production and fuel conversion efficiency”, Int. J. Hydrogen Energy, Vol. 29, pp.1409-1419, 2004.
21. Orhan Akansu S., Kahraman N., Ceper B.,”Experimental study on a spark ignition engine fuelled by methane–hydrogen mixtures” , Int. J. Hydrogen Energ ,Vol. 32, pp. 4279–4284, 2007.
22. Saravanan N., Nagarajan G., “An experimental investigation of hydrogen-enriched air induction in a diesel engine system”, Int. J. Hydrogen Energy, Vol. 33, pp. 1769-1775, 2008.
23. Gomes Antunes J.M., Mikalsen R., Roskilly A.P., “An experimental study of a direct injection compression ignition hydrogen engine”, Int. J. Hydrogen Energy, Vol. 34, pp. 6516-6522, 2009.
24.Abu-jrai A., Tsolakis A., Megaritis A., “The influence of H2 and CO on diesel engine combustion characteristics, exhaust gas emissions, and after treatment selective catalytic NOx reduction”, Int. J. Hydrogen Energy, Vol. 32, pp. 3565-3571, 2007.
25. Santoso W.B., Nur A., Ariyono1 S., Bakar R.A., “Combustion characteristics of a diesel-hydrogen dual fuel engine” , 2nd National Conference in Mechanical Engineering Research and Postgraduate Studies, pp. 22-32, 2010.
26. Yeh S.D., “The efficiency improvement of motorcycle engine running with reformulated hydrogen rich gas driven by exhaust energy”, Master Thesis, Department of Mechanical Engineering, NCHU, 2011.
27. Jhou J.Y., “An experimental study of the performance on reformer of fuel cell and effect of catalyst”, Master Thesis, Department of Mechanical Engineering, NTU, 2005.
28. United States Environmental Protection Agency, U.S. EPA, http://www.epa.gov/pm/.
29. Cloutman L.D., Dukowicz J.K., Ramshaw J.D., Amsden A.A., “CONCAS-SPRAY: A Computer Code for Reactive Flow with Fuel Sprays”, Los Alamos Scientific Laboratory Report, LA-9294-MS, 1982.
30. Amsden A.A., Butler T.D., O’Rourke P.J., Ramshaw J.D., “KIVA-A Comprehensive Model for 2-D and 3-D Engine Simulation”, SAE 850554, 1985.
31. Amsden A.A., “KIVA-3V, Release 2, Improvments to KIVA-3V,” Los Alamos National Laboratory report LA-13608-MS, 1999.
32. Liu C., “An experimental and analytical investigation into the combustion characteristics of HCCI and dual fuel engines with pilot injection”, Ph.D. Thesis, Dept. of Mechanical and Manufacturing Engineering, Calgary University, 2006.
33. Liu Y.F. , Pei P.C., “Asymptotic analysis on autoignition and explosion limits of hydrogen-oxygen mixtures in homogeneous systems”, International Journal of Hydrogen Energy, Vol. 31, pp. 639-647, 2006.
34. Seshadri K., Peters N., Paczko G., “Rate-ratio asymptotic analysis of autoignition of n-heptane in laminar non-premixed flows”, Comb. & Flame Vol. 146, pp. 131-141, 2006.
35. Liu S., Hewson J.C., Chen J.H., “Nonpremixed n-heptane autoignition in unsteady counterflow”, Combustion and Flame, Vol. 145, pp. 730-739, 2006.
36. Holman J.B., Experimental Methods for Engineers, McGraw Hill Publications, New York, 2003.
37. Vehicle Energy Laboratory, Kun Shan University, http://ksuvel.myweb.hinet.net/index-1.htm
38. Zeng S.Y., “Study on the effect of added ammonia on hydrogen production by water electrolysis”, Master Thesis, Department of Systems and Naval Mechatronic Engineering, NCKU, 2011.
39. Cruz-Peragón F., Jiménez-Espadafor F.J., Palomar J.A., Dorado M.P., “Influence of a combustion parametric model on the cyclic angular speed of internal combustion engines. Part I: setup for sensitivity analysis”, Energy & Fuels, Vol. 23, pp. 2921-2929, 2009.
40. Shudo T., Suzuki H., “Applicability of heat transfer equations to hydrogen combustion”, JSAE Rev., Vol. 23, pp. 303–308, 2002.
41. Ferguson C.R., Kirkpatrick A.T., Internal Combustion Engine Fundamentals: Applied Thermoscience, John Wiley & Sons, Inc., New York, pp.39-54, 2001.
42. Anderton D., Waters P.E., “Effect of Fuel Composition on Diesel Engine Noise and Performance”, SAE Technical Paper 820235, 1982.
43. Henningsen S., “Hydrocarbon Emissions from the Ignition-Delay Period in a Direct-Ignition Diesel Engine”, SAE Technical Paper 841381, 1984
44. Obert F.E, Internal Combustion Engines and Air Pollution, Index Education Publishers, New York, Chap2, 1973.