Ethanol is usually combined with gasoline to manufacture ethanol–gasoline with excellent combustion characteristics. However, extracting water from hydrous ethanol to manufacture anhydrous ethanol consumed much energy, which increases the production cost of ethanol–gasoline. Many researchers have studied the combustion and emissions of hydrous ethanol–gasoline to explore the application of hydrous ethanol–gasoline as the fuel for spark-ignition engines. Most previous studies changed the hydrous ethanol ratio with fixed purity in hydrous ethanol–gasoline to study the effects of hydrous ethanol. Different from previous studies, this paper studied the effects of water ratio (Wr) in hydrous ethanol on the combustion and emissions of a hydrous ethanol/gasoline combined injection engine under different excess air ratio (λ) values. The ratios of ethanol and gasoline keep constant, while the purity of hydrous ethanol changes during the research. The experiment adopted the combined injection mode with hydrous ethanol direct injection plus gasoline port injection; the direct injection ratio was 20%. The experiment set three λ (0.9, 1, and 1.2) and five Wrs (0, 5, 10, 15, and 20%). The test engine’s speed was 1500 rpm, and the intake manifold absolute pressure was 48 kPa. Results showed that water inhibited combustion, prolonged CA 0-10 and CA 10-90, reduced P_max and T_max, and delayed AP_max; larger λ made the deterioration on combustion more obvious, and the smaller λ had a larger tolerance to water. Water could increase torque and improve emissions, but different parameters corresponded to different optimal Wrs. For torque, the optimal Wr was 5%. For HC emissions, the optimal Wr was 0%; for CO emissions, the optimal value was 5%; and for NO_x emissions, the best value was 20%. The best Wr was 10% for particle number (PN) emissions. Under the optimal Wr condition, when λ values were 0.9, 1, and 1.2, compared with pure gasoline, the torque increased by 7.5, 5.54, and 5.31%; HC emissions decreased by 21.37, 23.43, and 26.58%; NO_x emissions decreased by 4.26, 11.47, and 12.55%; CO emissions decreased by 17.51, 34.56, −50%; and the total PN emissions decreased by 87.64, 89.64, and 76.07%.

中文翻译：

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不同过量空气比下含水乙醇中水比对含水乙醇/汽油联合喷射发动机燃烧和排放的影响

乙醇通常与汽油结合生产具有优良燃烧特性的乙醇-汽油。然而，从含水乙醇中提取水来制造无水乙醇消耗大量能源，这增加了乙醇-汽油的生产成本。许多研究人员对含水乙醇-汽油的燃烧和排放进行了研究，以探索含水乙醇-汽油作为火花点火发动机燃料的应用。大多数先前的研究改变了含水乙醇 - 汽油中固定纯度的含水乙醇比例，以研究含水乙醇的影响。与以往的研究不同，本文研究了不同过量空气比（λ）值下含水乙醇中的水比（Wr）对含水乙醇/汽油联合喷射发动机燃烧和排放的影响。乙醇和汽油的比例保持不变，而含水乙醇的纯度在研究过程中发生变化。试验采用含水乙醇直喷加汽油进气口喷射组合喷射方式；直喷比例为20%。实验设置了三个 λ（0.9、1 和 1.2）和五个 Wrs（0、5、10、15 和 20%）。试验发动机转速为1500 rpm，进气歧管绝对压力为48 kPa。结果表明，水抑制燃烧，延长 CA 0-10 和 CA 10-90，降低 和 20%）。试验发动机转速为1500 rpm，进气歧管绝对压力为48 kPa。结果表明，水抑制燃烧，延长 CA 0-10 和 CA 10-90，降低 和 20%）。试验发动机转速为1500 rpm，进气歧管绝对压力为48 kPa。结果表明，水抑制燃烧，延长 CA 0-10 和 CA 10-90，降低P _max和T _max，以及延迟AP _max；λ越大燃烧劣化越明显，λ越小对水的耐受性越大。水可以增加扭矩并改善排放，但不同的参数对应于不同的最佳 Wrs。对于扭矩，最佳 Wr 为 5%。对于 HC 排放，最佳 Wr 为 0%；对于 CO 排放，最佳值为 5%；对于 NO _x排放，最佳值为 20%。粒子数 (PN) 排放的最佳 Wr 为 10%。在最佳Wr工况下，当λ值为0.9、1、1.2时，与纯汽油相比，扭矩分别提高7.5、5.54、5.31%；HC排放量分别下降21.37%、23.43%和26.58%；NO _X排放量分别下降了 4.26、11.47 和 12.55%；CO 排放量减少 17.51、34.56、-50%；PN 排放总量分别下降 87.64、89.64 和 76.07%。