文章利用仿真和试验2种方式研究了不同转速和喷水量对发动机喷水蒸发过程、混合气形成过程和发动机性能及排放的影响。CA缸内直喷汽油机和进气道喷水系统组成汽油缸内直喷(gasoline in-cylinder direct injection,GDI)+进气道水喷射(wat...文章利用仿真和试验2种方式研究了不同转速和喷水量对发动机喷水蒸发过程、混合气形成过程和发动机性能及排放的影响。CA缸内直喷汽油机和进气道喷水系统组成汽油缸内直喷(gasoline in-cylinder direct injection,GDI)+进气道水喷射(water intake port injection,WPI)的双喷射发动机,建立发动机三维计算模型,标定喷雾和燃烧模型,并仿真喷水过程。结果表明:增加喷水量会提高水的湿壁量,缸内水蒸气质量增加但质量比下降;喷水使汽油蒸发受阻;喷水并增大点火提前角使比油耗降低,热效率提高,但排放未明显降低。展开更多
Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a genera...Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a general,surfactantfree,large-scale synthesis approach for Fe3 O4 spheres.Herein,we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe3 O4 spheres with the yield of 5.1 g,which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe3+/COO-in the solution.Particularly,it is observed that the reactants undergo a redox process,composed of a precipitation-dissolution equilibrium combined with a coordination reaction(termed as RPC),to the final product based on the LaMer model.It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe3 O4 spheres.This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process,but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe3 O4 spheres in the absence of surfactants.展开更多
文摘文章利用仿真和试验2种方式研究了不同转速和喷水量对发动机喷水蒸发过程、混合气形成过程和发动机性能及排放的影响。CA缸内直喷汽油机和进气道喷水系统组成汽油缸内直喷(gasoline in-cylinder direct injection,GDI)+进气道水喷射(water intake port injection,WPI)的双喷射发动机,建立发动机三维计算模型,标定喷雾和燃烧模型,并仿真喷水过程。结果表明:增加喷水量会提高水的湿壁量,缸内水蒸气质量增加但质量比下降;喷水使汽油蒸发受阻;喷水并增大点火提前角使比油耗降低,热效率提高,但排放未明显降低。
基金financially supported by the National Natural Science Foundation of China(51631001,51672010 and81421004)the National Key R&D Program of China(2017YFA0206301 and 2016YFA0200102)
文摘Fe3 O4 has attracted tremendous interest in vast areas of biomedicine and catalysis as well as environment engineering.However,it is highly desired to fully understand the chemical kinetic process and propose a general,surfactantfree,large-scale synthesis approach for Fe3 O4 spheres.Herein,we developed a facile scalable solvothermal method in the absence of surfactants to produce Fe3 O4 spheres with the yield of 5.1 g,which present tunable sizes from 107 to 450 nm by modulated molar ratio of Fe3+/COO-in the solution.Particularly,it is observed that the reactants undergo a redox process,composed of a precipitation-dissolution equilibrium combined with a coordination reaction(termed as RPC),to the final product based on the LaMer model.It is worth noting that the generation of di-carboxyl group and its coordination with iron cations determine the formation of Fe3 O4 spheres.This work not only offers a strategy to precisely tailor the particle size in scalable synthesis process,but also gives the insight on the role of dihydric alcohol in the formation mechanism of Fe3 O4 spheres in the absence of surfactants.
