学术论文

      弹性模量对生物柴油喷油时刻影响的研究

      Effect of the bulk modulus on injection timing of biodiesel

      摘要:
      为研究燃油喷射系统中燃油物理特性参数对喷油时刻的影响,基于燃油密度、体积弹性模量随温度和压力变化的经验公式,建立了柴油机泵-管-嘴燃油喷射系统喷油延迟计算模型.结果表明:随着压力增加或温度下降,燃油的密度和体积弹性模量都呈线性增长趋势,且两种生物柴油的密度和体积弹性模量较为接近,但与柴油的差异明显.在温度20 ℃及压力10 MPa时,生物柴油(大豆油甲酯)的体积弹性模量比柴油高约182.0 MPa,且随着压力的升高,两者之间的体积弹性模量差值变小,但生物柴油的体积弹性模量仍高于柴油.以某490柴油机的燃油输送系统为例,在温度40 ℃和压力20 MPa条件下,由于生物柴油(大豆油甲酯)的体积弹性模量高于柴油约132.2 MPa,从喷油泵泵油到喷油器针阀开启的这段行程中,其所需输运时间比柴油提前约0.5 °CA.该方法简单快捷,研究成果可为燃油喷射系统的设计提供参考.
      Abstract:
      In order to explore the influence of physical properties on fuel injection timing, a simplified model is established to estimate the injection delay for a conventional pump-line-nozzle fuel injection system of diesel engines by using empirical formulas of fuel density and bulk modulus.It is revealed that the density and bulk modulus of fuels arise linearly with the increase of pressure or the decrease of temperature.The density and bulk modulus of two types of biodiesel are equal relatively, but obviously different from diesel.Under the ambient condition of 20 ℃ and 10 MPa, the bulk modulus of biodiesel (soybean methyl ester) is 182.0 MPa higher than that of diesel.With the increase of pressure, the difference of bulk modulus between biodiesel and diesel declines.Nevertheless, the biodiesel still has higher bulk modulus than diesel.As for the fuel delivery system in a conventional 490 diesel engine, under the ambient condition of 40 ℃ and 20 MPa, due to that the bulk modulus of biodiesel (soybean methyl ester) is 132.2 MPa higher than that of diesel, the required time to deliver biodiesel from the piston pumping to the nozzle opening can be shortened by 0.5°CA than that of diesel.According to the result, this method is convenient and accurate.Meanwhile, the results can provide reference for the design of the fuel injection system.
      作者: 顾萌 [1] 梅德清 [1] 王恒全 [1] 袁银男 [2]
      Author: GU Meng [1] MEI De-qing [1] WANG Heng-quan [1] YUAN Yin-nan [2]
      作者单位: 江苏大学汽车与交通工程学院,江苏镇江,212013 江苏大学汽车与交通工程学院, 江苏镇江212013;苏州大学能源学院, 江苏苏州215006
      年,卷(期): 2017, 42(2)
      分类号: TK421
      在线出版日期: 2017年5月16日
      基金项目: 国家自然科学基金资助项目,江苏高校优势学科建设工程资助项目