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|Issue Date: ||2009-08-13 23:55:24 (UTC+8)|
|Abstract: ||因應世界能源日益耗竭窘境與生態環境嚴重惡化困境，有效利用能源及降低污染排放是世界各國目前極為迫切的主要課題。台灣及東南亞國家的機車數量龐大，為都會區的主要空氣污染源主要之移動污染源之ㄧ；美國亦逐步管制割草機等路外內燃機具之廢棄排放濃度。製造廠商必須尋求有效降低廢氣排放之適當技術，以因應日趨嚴格之廢氣排放標準。以電漿重組器產生之富氫氣體，與汽油混合後作為機車、割草機等內燃機之燃料，可以有效降低內燃機排放之廢氣濃度，並兼具降低油耗、提升馬力之優點。以汽油為燃料之電漿重組器與機車、割草機之整合，可切入市場需求。此外，富氫氣體亦可作為SOFC 之燃料來源，或經過後續處理程序，降低CO濃度後，供應PEMFC 使用。電漿重組器產生之富氫氣體，應用範圍廣泛，汽油、柴油、甲醇、乙醇、LPG 及天然氣等液、氣體燃料均可以作為重組反應的燃料，燃料來源相當多元化。應用電漿技術時需在氣相環境下工作，因此液態燃料必須經過霧化及汽化過程才可導入重組器進行轉化產氫反應。故計畫首先規劃、設計及製作適用於汽油等液體燃料之超音波震盪子，使霧化後之燃料液滴經由適當之氣流導引進入後續之汽化、重組單元，避免凝結於管壁上。結果顯示自製無鉛陶瓷(BNT)的超音波壓電片所產生壓電特性遠低於傳統鈦酸鋯鉛(PZT)，BNT 超音波震盪子霧化效果不佳，因此採用市面現有的PZT 超音波壓電片並製作超音波震盪子，結果顯示超音波霧化器使用單一探頭超音波探頭汽油霧化量最高可達到 3.0g/min。本計畫將超音波霧化器與重組器裝置於實車上，配合燃料及空- 2 -氣供應控制系統於車體動力計上進行測試。92 汽油經由超音波震盪子有效霧化成為4μm 的微小液滴，經吸熱汽化流入重組器，經電漿重組器重組產出之富氫氣體導入引擎為添加燃料，進行實車測試。以瞭解導入富氫氣體之後的行車性能、燃料消耗及污染排放等特性。本研究以流率分別為5.0、7.5、10.0 及12.5L/min 的空氣由超音波霧化器攜帶出霧化之汽油，O2/C 固定為0.55 做為實車行駛時重組器的操作參數。於實車測試，定速40km/h 時，採用7.5L/min 攜行空氣，能量消耗改善率最佳可達9.18 %；車速50km/h 時改善率約為3.9%；60km/h 時改善則不明顯。而NOx 排放的改善效果則較為明顯，在車速為40 km/h 時，NOX 改善率最佳達81.52 %；車速為50 km/h時，NOX 改善率最佳達73.23 %；車速為60 km/h 時，NOX 改善率最佳高達60.22 %。整體而言，採用汽油重組之系統與去年所採用之以丁烷為燃料的重組器比較，可得知使用汽油為燃料者NOx 的改善較為明顯。In order to solve the problems of the shortage of energy resourcesand the requirement of ecological environment protection theimprovement of fuel economy and exhaust emissions has become one ofthe most significant issues nowadays. The main moving pollutionsources in urban areas in Taiwan and in other countries in Southeast Asiaare caused by a huge quantity of motorcycles. In addition, except fortransportation vehicles, the government of the United States of Americaalso made the regulation to control progressively the waste gasdischarged by other internal-combustion engines like mowers.Manufacturers must seek proper technology to reduce the waste gasdischarges effectively in order to satisfy the more rigorous standard ofexhaust emission. It has been shown that a reformer used to producehydrogen-rich gas for the additive fuel of internal-combustion engineslike motorcycles; mowers etc not only reduce the concentration ofdischarge gas but have advantage of reducing the oil consumption andimproving horsepower concurrently. Motorcycles or mowers with agasoline based reformer are in great demand. In addition, thehydrogen-rich gas can also be regarded as the fuel source of SOFC orcan be supplied for PEMFC after reducing the concentration of CO.Reformers generated hydrogen-rich gas can be applied to many fields.Several kinds of fuel sources for reformers are petrol, diesel oil, methylalcohol, ethanol, LPG and natural gas.Nevertheless, due to the fact that plasma works under theenvironment of gaseous phase, liquid fuel must vaporize throughatomization process and then flow through a reformer to generatehydrogen-rich gas. This project will first develop proper ultrasound- 4 -transducers to nebulize liquid fuel and design and fabricate an atomizerproduct. To avoid the damage of lead oxide the feasibility of usinglead-free piezoelectric ceramics is investigated. Results show that thedielectric properties of lead-free piezoelectric ceramic BNT are inferiorto those of PZT ceramic. Therefore, a commercial PZT chip was chosenand then fabricated a transducer. Results show that the maximum massflowrate of nebulized liquid fuel is 3.0 g/min.In this project, an ultrasound atomizer and a reformer were installedonboard the motorcycle to produce hydrogen-rich gas and then weretested on the chassis dynamometer. 92 gasoline liquid fuel was nebulizedinto 4 μm micro droplets and then mixed with suitable air flow rate intothe plasma reformer to produce hydrogen-rich gas, and used as thesupplementary fuel of the engine. The experiments of running conditionswere conducted, and the driving performance, fuel consumption andexhaust emissions of the motorcycle were measured.The air flow rate of 5.0, 7.5, 10.0 and 12.5 was induced into theatomizer to carry out the vaporized gasoline into the reformer; and theO2/C of 0.55 was chosen as the reforming parameter. As for the results ofthe vehicle experiments, it showed that 9.18% improvement of energyconsumption was achieved at the vehicle speed of 40km/h; and 3.9%improvement at 50km/h; however, at the speed of 60km/h, theimprovement of energy consumption was insignificant. Furthermore, thebest improvement of NOx emission was obtained as high as 81.53% forthe vehicle speed of 40km/h, and 73.23% and 60.22% improvementunder the driving speed of 50 and 60km/h, respectively. As a whole, theimprovement of NOx emission is more significant by gasoline reformingthan that of by butane reforming to produce hydrogen-rich gas as thesupplemental fuel of the engine.|
|Appears in Collections:||[機械工程系所] 研究計畫|
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