隨著各國研擬愈加嚴格的空氣汙染法條，目的是要減少細懸浮微粒(PM2.5)、氮氧化物(NOX)及硫氧化物(SOX)的排放總量，進而解決空氣品質逐漸惡化的情況。近年來，許多專家學者研發出替代性燃料，並且深入探討該如何降低汙染物質的排放，設法解決能源耗竭與環境遭受破壞的問題。
本研究選用丁醇作為柴油引擎的輔助燃料，是因為丁醇不僅屬於富氧燃料，同時具有較高的蒸發潛熱以及較低的熱值，這些性質雖然能使Smoke和NOX的排放降低，卻會造成HC以及CO的排放增加；因為綠色柴油具有較高的十六烷值、低密度及優異的冷流特性，所以將綠色柴油混摻入純柴油中，可以抑制各類汙染物的排放量。
本研究另外一部分則是建構共軌噴射系統，將共軌噴射系統安裝於直噴式（Direct-Injection Type）柴油引擎上，輔以高壓泵浦加壓燃油，再將加壓後的高壓燃油，送入共同油軌(Common Rail)內。共同油軌內具有調壓閥裝置，能維持油壓在一定高壓範圍內；並於外側裝設回油管路，能夠將多餘的燃油送回燃油櫃。燃油則經由共同油軌進到高壓油管，輸送到氣缸內的電磁式噴油嘴。高壓噴射微電腦控制器依照電腦程式所規劃的觸發訊號和噴射週期，於適當時機下傳遞控制訊號到噴油嘴驅動裝置，以驅動噴油嘴噴油或停止噴油。
另外，並利用現有的單缸直噴式柴油引擎，使用綠色柴油混摻柴油，並於進氣處添加丁醇調節閥，可持續供應固定流量之丁醇，配合EGR來減少廢氣中的NOx濃度。經由改變引擎轉速、負荷及EGR比例進行交叉比對實驗，探討使用綠色柴油混摻柴油及進氣處噴入丁醇後，對柴油引擎性能之污染排放物所造成的影響。配合模擬程式KIVA-3V,RELEASE2調整程式中的進氣組成，並執行數值運算分析，探討進氣處添加丁醇後，對柴油引擎特性與燃燒所造成的影響，將模擬中關於汙染物質的計算與缸內壓力之結果與實驗所獲得數據相互印證。
本研究結果顯示，成功將共軌噴射系統架設於新購單缸柴油引擎，並且完成運轉測試。同時完成丁醇手動導入系統及EGR系統於原有之單缸柴油引擎，使用綠色柴油混摻柴油進行引擎實驗時，同時於進氣處噴射丁醇並導入EGR進行。顯示綠色柴油混摻比率越高的燃油，燃燒後所排放的CO、HC、NOX、Smoke及PM2.5都有降低的趨勢。丁醇比例越高也越能抑制NOX、Smoke及PM2.5，EGR比例越高雖可降低NOX，但對於Smoke有較負面的影響。此外，數值模擬與實驗的結果誤差約3%以下，所得到結論可相互對應，由此證實本研究採用程式的可信度。

As countries promote more stringent air pollution-related laws, the goal is to reduce the total amount of fine suspended particulates (PM2.5), nitrogen oxides (NOX), and sulfur oxides (SOX) to address the deterioration of air quality. In recent years, many experts and scholars have developed alternative fuels and explored ways to reduce emissions of polluting substances. They struggle to solve the problem of energy shortage and environmental damage.
In this study, butanol was chosen as the auxiliary fuel for diesel engine because it not only is an oxygen-rich fuel but also has a higher latent heat and lower heating value, which can reduce smoke and NOX emissions but increase HC and CO emissions. Since HVO has properties of higher cetane number, lower density, and excellent cold flow value, this work blended HVO with diesel fuel to suppress the emission of various pollutants.
The other part of this study is to construct a common rail injection system. The common rail injection system is installed on the direct-injection type diesel engine. The high-pressure pump pressurize the diesel fuel at first, and then the pressurized diesel fuel is fed into the common rail, which has a regulating valve device to maintain the diesel fuel pressure in a certain high-pressure range. The common rail also has the overflow pipe which was connected to the common rail for returning excess diesel fuel back the fuel tank. The high-pressure injection microcomputer controller will transmit control signals to the injector receiver unit at the appropriate time according to the computer programmed trigger signal and injection period to drive the injector to inject or stop injecting diesel fuel.
In addition, operating the existing single-cylinder direct injection diesel engine employs diesel oil blended with HVO and adds a butanol regulation at the intake, which supplies the constant flow rate, conjunction with EGR system to reduce NOX concentration in the exhaust gas. The cross-comparison experiments were conducted by varying the engine speed, load, and EGR ratio to examine the effect on the performance of the diesel engine pollution emissions using diesel oil blended with HVO and injecting butanol at the intake. The simulation program KIVA-3V, RELEASE2 was used to adjust the intake composition and perform numerical analysis for investigating the effect and combustion conditions of adding butanol at the intake place of a diesel engine. The results of the calculation of the pollutants and the cylinder pressure in the simulation are confirmed with the data obtained from the experiment.
The results of this study showed that the common rail fuel injection system was successfully installed in the newly purchased single-cylinder diesel engine and the operational test was completed. This study also finished the engine test with injecting butanol manually and EGR system at the intake of the original single-cylinder diesel engine with diesel oil blended with HVO at the same time. As the higher percentage of HVO is blended with diesel oil, the lower emissions of CO, HC, NOX, Smoke and PM2.5 tend to be. The higher percentage of butanol can also suppress NOX and Smoke. The higher EGR ratio can reduce NOX, but it has more negative effect on Smoke. The addition of butanol results in a significant reduction of NOX. In addition, the discrepancy between the numerical simulation and the experimental results is less than 3%, which confirms the reliability of the program used in this study.

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