喷油压力对GDI积碳喷嘴喷雾特性的影响  

Effects of injection pressure on atomizing characteristic of deposit nozzle of GDI engine injector

作　　者：宛仕枨 黄豪中[1] 刘勰[1] 杨升[1] 王腾[1] 

机构地区：[1]广西大学机械工程学院,广西南宁530004

出　　处：《广西大学学报（自然科学版）》2016年第2期404-411,共8页Journal of Guangxi University（Natural Science Edition）

基　　金：广西自然科学基金资助项目(2014GXNSFGA118005);广西高等学校优秀中青年骨干教师培养工程资助项目(桂教人(2013)16号)

摘　　要：喷油器积碳是直喷汽油机(GDI)面临的主要问题之一,提高喷油压力可以改善直喷汽油机的喷雾特性和燃烧特性。在自行设计的定容燃烧弹内,研究了两种喷油压力(4 MPa和7 MPa)对3支积碳程度不同的直喷汽油机喷油器喷雾锥角和贯穿距的影响。结果表明,喷油压力从4 MPa提高到7 MPa时,所有喷油器的喷雾锥角均增大,但增加的幅度有所不同,积碳严重的喷油器在喷油过程中喷雾锥角增加的幅度最大,大约增加了25°,积碳较少的喷油器和无积碳喷油器增加幅度相差不大,大约增加了7°。随着喷油器积碳程度的增多,喷雾锥角呈增大的趋势。燃油喷射结束后,喷雾锥角变化不大,主要是由于此时受环境背压的影响。喷油压力较小时,积碳喷油器喷雾锥角变化的波动范围较大,而喷油压力较高时,积碳喷油器喷雾锥角波动范围变化则较小。积碳喷油器贯穿距增长幅度在喷雾发展过程中受喷油压力和积碳程度的影响较小。喷雾的发展速度在各阶段是不同的,低喷油压力时,积碳喷油器的贯穿距均大于无积碳贯穿距,较少积碳喷油器的贯穿距大于最多积碳喷油器的贯穿距,随着喷雾的发展这一趋势并未改变。高喷油压力时,积碳会抑制喷雾贯穿距的增长,较少积碳喷油器的贯穿距始终大于最多积碳喷油器的贯穿距,无积碳喷油器的起始贯穿距小于另两支喷油器,但最后无积碳喷油器的贯穿距大于另两支喷油器贯穿距。The carbon deposit of injector is one of the major problems of direct injection gasoline engine（ GDI）. Increasing injection pressure can improve the spray characteristic and combustion characteristic of gasoline engine. Three different deposit levels of gasoline injectors and two different injection pressures（ 4 MPa and 7 MPa） were used in this research in the constant volume. From the research the conclusions are as follows. When the injection pressure increases from 4 MPa to 7 MPa,all injector spray cone angles increase,in the process of fuel injection,the serious carbon depositinjector has the larger spray cone angle,which has increased about 25°. The spray cone angles of other two injectors approximately increase about 7°. With the increasing of carbon deposit,the spray cone angle showed an increasing trend. After the end of the fuel injection,spray cone angles change little because of the backpressure. When the injection pressure is low,the fluctuation ranges of spray cone angle of carbon deposit injectors are large,while the fluctuation ranges of spray cone angle of carbon deposit injectors are small at the high injection pressure. The growth of spray penetration about carbon deposit injector are less influenced by injection pressure and carbon deposit in the process of spray. The velocity of spray is different in the process of spray. At the low injection pressure,the spray penetrations of carbon deposit injectors are greater than that of no-carbon injector;the spray penetration of less carbon deposit injector is larger than that of the most carbon deposit injector. This trend has not changed. At the high injection pressure,carbon deposit will decrease the growth of spray penetration. The spray penetration of less carbon deposit injector is always greater than that of the most carbon deposit injector,while the starting spray penetration of no-carbon deposit injector is less than those of injectors,but in the end the spray penetration of no-carbon deposit injector is greater than those of two inje

关 键 词：喷油压力 直喷汽油机 喷嘴积碳 喷雾锥角 贯穿距 

分 类 号：TK411.2[动力工程及工程热物理—动力机械及工程]