缸內直噴引擎(Gasoline Direct injection,GDI) 在低負載低轉速下以層狀燃燒模式(Stratified Mode Operation) 下進行運轉，在火星塞附近濃油，缸內整體貧油的狀況下，達到稀薄燃燒的效果，以達到低排放、低油耗的效果。以數學方程式來模擬內燃機的循環運作與燃燒反應，能讓引擎的研究有所了解之外，也能使研發成本降低，引擎燃燒方面可以由質量燃燒分率（Mass Fraction Burn, MFB) 曲線來表示，使用韋伯函數(Wiebe Function) 來做曲線擬合，量化引擎燃燒的現象，它被廣泛運用在不同燃燒系統與不同類型的內燃機上，來了解引擎燃燒結果並分析。本研究針對一wall-guided 渦輪增壓缸內直噴(Gasoline Direct Injection, GDI) 引擎來進行研究，透過調變點火角度來觀察引擎熱釋放變化，接著使用雙韋伯函(Double Wiebe Function)來擬合實驗的熱釋放曲線，藉由雙韋伯函數中9 個不同參數的變化，來得到不同點火角度對引擎的熱釋放影響並觀察層狀燃燒(Stratified Mode) 的第一階燃燒與第二階燃燒的變化。

A gasoline direct injection(GDI) engine operates in stratified mode operation at low load and low speed. High mixture concentration near the spark plug but overall lean mixture inside the cylinder achieve lower emissions and better fuel consumption as lean combustion. Using mathematical equations to simulate the combustion of internal combustion engines can not only have an understanding of engine research, but also reduce research and development costs. Engine combustion can represent by mass fraction burned curve, using wiebe function to do curve fitting to quantify the phenomenon of engine combustion. It is widely used in different types of internal combustion engines to understand the result of combustion. This paper uses a wall-guided GDI engine with a turbocharger system. Spark timing is adjusted in order to observe the heat release of engine, and then use double wiebe function to fit the experiment heat release curve. Through the results of 9 different parameters in double wiebe function, we can obtain the effect of different ignition angles on the engine and observe the changes in the 1st Stage Combustion and 2nd Stage Combustion of the stratified mode operation.

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