本研究探討二閥單缸四行程預燃室引擎汽缸內的燃燒情形、汙染物生成量與引擎性能，並與單火星塞引擎、雙火星塞引擎做比較。使用商業套裝計算流體力學軟體CONVERGE分析二閥單缸四行程預燃室引擎，在引擎轉速固定5500RPM、進氣效率37%時，改變預燃室噴孔數目n、噴孔等總截面積無因次參數β、噴孔傾斜角δ、噴孔圓周角γ、預燃室空燃比(A/F)PC、預燃室噴油時機to、預燃室點火時機ti、主燃室空燃比(A/F)MC，分析 (1)汽缸內平均壓力峰值、(2)平均溫度峰值、(3)輸出指示功、(4)熱效率、(5)燃燒持續角度、(6)單位燃料消耗量等六個性能量化指標以及燃燒後產物(1)碳氫化合物質量、(2)氮氧化合物質量、(3)一氧化碳質量、(4)二氧化碳質量等四個汙染量化指標，並探討缸內溫度分布、油氣濃度分布與火焰傳遞行為。 比較預燃室引擎、單火星塞引擎、雙火星塞引擎的量化指標，判斷預燃室最佳噴孔幾何設計以及物理參數。計算分析結果顯示，當(A/F)MC = 14.5時，選擇預燃室噴孔設計(n, β, δ, γ) = (5, 0.5, 75°, 6°)以及物理 參數(to, ti) = (690°, 700°)、(A/F)PC = 14 ~15可得到最大的預燃室引擎的缸內平均壓力峰值、平均 溫度峰值、輸出指示功、熱效率、最短的持續燃燒角度、氮氧化合物排放增加(但仍低於法規標準值，可使用三元觸媒降低 )、碳氫化合物排放減少(遠低於法規標準值 )。這些結果表示預燃室技術有助於提升缸內燃燒效率並改善污染排放。另外，為了使燃油消耗更具經濟效益，可利用稀薄燃燒改變預燃室引擎(A/F)MC至16 雖然會犧牲少許性能，但可以提升燃油經濟性以及降低汙染排放，與單火星塞引擎相比，可減少油耗28%。

The characteristics of flow, fuel distribution, combustion, power performance, and pollutant generation of a prechambered, two-valve, four-stroke reciprocating engine were analyzed using the commercial CFD code of CONVERGE. The engine speed and the intake efficiency were set at 5500 RPM and 37%, respectively. The typical parameters such as peak mean pressure, peak mean temperature, indicated work, thermal efficiency, crank angle at 10% - 50% MFB (mass fraction burning), specific fuel consumption, amount of flame remaining before exhaust valve opening, the masses of hydrocarbon, nitrogen oxides, carbon monoxide, and carbon dioxide were calculated. The results were compared with corresponding those of a single-spark-plug engine and four types of dual-spark-plugs engines. The prechamber orifice geometric parameters (i.e., orifice numbers n, equivalent and dimensionless of total cross-sectional area β, tilt angle δ and circumferential angle γ) as well as the physical parameters (i.e., air-fuel ratio of prechamber (A/F)PC, oil injection time of prechamber to, spark time of prechamber ti, air-fuel ratio of main chamber (A/F)MC) were focused for analysis. The results showed that by optimizing the prechamber orifices diameter and arrangement, the prechambered engine presented significant improvement in engine performances compared with corresponding those of other engines. The optimized parameters (n, β, δ, γ, to, ti) = (5, 0.5, 75°, 6°, 690°, 700°) could lead to increase of engine power output by 34% and reduce the mass of hydrocarbon emission by 77% at (A/F)PC = 14 - 15 when compared with corresponding those of the single-spark-plug engine. At lean-burn combustion, the engine performances of the optimized prechambered engine were supreme when compared with those of the single-spark-plug engine. The specific fuel consumption of the prechambered engine operated at the lean-burn condition of (A/F)MC = 16 could be drastically lowered by 28% when compared with that of the single-spark-plug engine.

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