富氫氣體為輔助燃料之機車引擎性能與污染排放特性研究

Study on the performance and exhaust emissions of motorcycle engine fuelled with hydrogen-rich gas fuel

許晉嘉(Chin-Chia Hsu)

指導教授 ： 洪榮芳

崑山科技大學/工程學院/機械工程研究所/碩士(2007年)

https://doi.org/10.6828/KSU.2007.00024

摘要

本文針對富氫氣體導入四行程機車引擎之運轉特性進行探討。實驗研究分兩部份進行，第一部份以CO、CO2、H2及N2依比例混合成富氫氣體，實驗參數主要為富氫氣體供應率及氫氣質量百分比(2~12%)。第二部份則以電漿重組器產生富氫氣體，實驗參數主要為控制不同丁烷與空氣供應率進行重組，使O2/C(氧/碳莫耳數)比固定為0.70。並配合油門開度(1/6-6/6)及引擎轉速(3000-6000rpm)之變化，進行引擎性能及污染排放等實驗研究。
第一部份的混合富氫氣體實驗結果得知，在中、低油門時之最佳熱效率介於24.0-28.0%之間，富氫氣體體積百分比介於6.7-8.1%之間。在低油門開度時，引擎轉速3000-5000rpm者的氫氣質量百分比介於2.0-4.0%之間，NOX無改善，其他狀況的NOX改善率均在20%以上，最高可達98%。中油門者，引擎轉速4000rpm、氫氣質量百分比為2.0%及4.0%之NOX無改善之外，其他狀況均有改善。油門全開者以原引擎熱效率最佳，約31.4%。在引擎轉速6000rpm、氫氣質量百分比2.0%等狀況NOX無改善，其他狀況則均有改善。

第二部份實驗結果得知，重組器產生富氫氣體者，在中、低油門時，除引擎轉速3000rpm者之外，以原引擎熱效率最高，約介於13.0-24.5%之間。在油門全開時，引擎轉速4000rpm及5000rpm者，添加富氫氣體者的熱效率最佳，約為32.0%左右，其富氫氣體體積百分比約介於3.5-4.2%之間，其氫氣質量百分比約1.6-2.6%。另外，在低油門者，NOX均無改善。中、高油門者， NOX改善率均可達45%以上，油門全開時甚至可高達90%以上。

由引擎汽缸壓力分析結果得知，添加適量的富氫氣體，可改善燃燒的穩定性。在本研究中，以0.70L/min的丁烷供應率重組成富氫氣體導入引擎者，可獲得最低的變異係數。導入太多的富氫氣體(以1.4L/min丁烷重組者)，除了最高壓力會降低之外，其變異係數也會提高，造成引擎的不穩定運轉。

關鍵字

重組器 ； 污染排放 ； 富氫氣體 ； 機車引擎

並列摘要

The performance and emissions of a 4-stroke motorcycle engine fuelled with hydrogen-rich gas were studied in this paper. This thesis consists of two parts. First, the H2-rich gas was mixed with CO, CO2, H2 and N2. The effects of H2-rich gas volume rate and H2 mass ratios on the performance and exhaust emissions were studied. Second, the H2-rich gas was generated by a plasma-catalyst reformer. The H2-rich gas was reformed from the air-butane mixture by an onboard plasma-catalyst reformer at a constant O2/C molar ratio of 0.70. The studied parameters included butane flow rate for reformer, engine speed and throttle opening. The engine performance and exhaust emissions were investigated.

The results of the first part showed that the best thermal efficiency appeared around 24-28% under the H2-rich gas volume ratio of 6.7-8.1% for 1/6 and 3/6 throttle opening. Further, it was found that NOX increased with H2 mass ratio of around 2.0-4.0% under the engine speed of 3000-5000rpm for 1/6 throttle opening. The improvement of NOX could be over 20%, or even as high as 98% for other conditions at this throttle opening. NOX was improved for the case of 3/6 throttle opening except the engine speed of 4000rpm with H2 mass ratio of 2.0% and 4.0%. The best thermal efficiency was about 31.4% for the case of WOT (Wide Open Throttle) without H2-rich gas addition. NOX improvement was also found for the case of WOT except an engine speed of 6000 rpm with 2.0% H2 mass ratio.

Further, the conclusions for H2-rich gas generated by the plasma-catalyst reformer were drawn as followed. Under the cases of 1/6-3/6 opening, except the engine speed of 3000 rpm, the original engine had the best thermal efficiency, which was around 13.0-24.5%. For the WOT condition, the best thermal efficiency was around 32.0% with the H2-rich gas volume ratio of 3.5-4.2% and H2 mass ratio of around 2.0-4.0% under the engine speed of 4000-5000rpm. Furthermore, NOX could not be improved for the case of 1/6 throttle opening. However, for the cases of 3/6-6/6 throttle opening, over 45% NOX improvement was obtained. Even over 90% improvement in NOX could be achieved for the case of WOT.

The results of the cylinder gas pressure showed that the better combustion stability was obtained with the suitable ratio of H2 addition. In this study, the lowest coefficient of variation of maximum pressure was got under the butane supply rate of 0.70 L/min for reformer. Low maximum pressure, high coefficient of variation of maximum pressure and unstable engine operation were attained for high ratio of H2-rich gas addition.

並列關鍵字

reforming ； hydrogen-rich gas ； exhaust emission ； motorcycle engine

參考文獻

[11] H.S. Yi, S.J. Lee and E.S. Kim, “Performance Evaluation and Emission Chanacteristics of In-Cylinder Type Hydrogen Fuelled Engine,” Int. J. Hydrogen Energy, Vol. 21, 1996, pp. 617-624.

[12] P. V. Blarigan and J.O. Keller, “A Hydrogen Fuelled Internal Combustion Engine Designed for Single Speed/Power Operation,” Int. J. Hydrogen Energy, Vol. 23, No. 7, 1998, pp. 603-609.

[13] H. A. S. Al-Janabi and M. A. S. Al-Baghdadi, “A prediction Study of the Effect of Hydrogen Emission of a Four Stroke Spark Ignition Engine,” Int. J. Hydrogen Energy, Vol. 24, 1999, pp. 363-375.

[14] M. A. S. Al-Baghdadi and H. A. S. Al-Janabi, “Improvement of Performance and Reduction of Pollutant Emission of a Four Stroke Spark Ignition Engine Fuelled with Hydrogen-Gasoline Fuel Mixture,” Energy Conversion and Management, Vol. 41, 2000, pp. 77-91.

[15] H.S. Yi, K.Min and E.S. Kim, “The Optimised Mixture Formation for Hydrogen Fuelled Engines,” Int. J. Hydrogen Energy, Vol. 25, 2000, pp. 685-690.