燃料與空氣的準備與進入燃燒室前的混合對於內燃引擎的燃燒與污染排放是一個很重要的參數，本研究的目的就要探討缸內直噴用燃料噴嘴在不同外界壓力環境下隨著不同噴霧時間所顯現的噴霧特徵。本研究使用博世(BOSCH)所生產市售之單孔缸內直噴噴嘴作為測試對象，搭配一自行設計並製作之高壓艙已進行相關測試，該高壓艙配有光學透視視窗以利雷射光學之應用。本研究運用以雷射光學為基礎之定量化視流法技術以分析各種噴霧特徵包括：噴霧演化、噴霧端點滲透深度、噴霧錐角與噴霧前緣速度。這些在不同壓力下的噴霧特徵將可以做為將來設計缸內直噴引擎、修改現有引擎以及開發引擎庫控制策略之基礎資料。

Preparation of fuel and air is an important factor in improving combustion process and emission of internal combustion engine. The objective of the present study is to analyze the spray characteristics of injector for GDI engine according to the injection time under ambient pressure conditions. Investigations in the present study are carried out using a mass-production single-hole injector which is manufactured by BOSCH for GDI engine. A pressure chamber with optical access windows was designed and fabricated which can simulate different environmental pressure. The spray characteristics in terms of evolution of spray tip penetration depth, spray cone angle, and spray front velocity are measured by using laser-based quantitative flow visualization technique. The spray characteristics in different pressure environments provide the basis for gasoline direct injection engine design, modifications of current engine and development of control strategy.

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