Effects of Injection Timing on Fuel-Air Interaction in a Direct Injection Gasoline Engine

直接汽油噴射引擎注油時機對燃油空氣交互作用之影響探討

10.6124/TAASRC.200003_32(1).07

卓英吉(Ying-Chi Chuo)；江滄柳(Tsung-Leo Jiang)

注油時機 ； 直接噴射 ； 汽油引擎 ； 壁溼 ； Injection Timing ； Direct Injection ； Gasoline Engine ； Wall Wetting

中國航空太空學會學刊

32卷1期（2000 / 03 / 01）

64 - 72

英文

本研究採用三維數值模擬計算方法，針對直接汽油噴射引擎內注油時機對可燃混合氣形成之影響進行探討。進氣與壓縮行程內不同注油時機產生之流場特性已成功地模擬。計算結果顯示汽缸內氣相溫度皆因燃油之直接噴射而降低。於進氣行程內注油通常不利氣相流場之發展，然而於壓縮行程內注油則有利汽缸內之滾轉運動、紊流強度，有利於油氣混合。燃油於汽缸壁及活塞面造成之壁溼現象，皆不可避免地出現於所有例子中，尤以於壓縮行程內注油時較嚴重。

Effects of injection timing on the process of mixture preparation in a direct injection gasoline engine are investigated by employing full-scale multidimensional numerical simulations. The flow characteristics are predicted for both early and late injection conditions. The numerical results show that the gas temperature inside the cylinder of both early and late injection schemes is relatively lower than that without spray injection. The early injection scheme generally degenerates the gas flow motion, while the late injection scheme promotes the tumble motion and enhances the turbulence intensity. Wall wetting phenomena are shown unavoidable in all of the investigated cases. It is, however, more severe for the cases of late injection scheme.