船用柴油机超高压共轨系统喷雾特性试验研究

Experimental study on spray characteristics of ultra high pressure common rail system for marine diesel engine

利用自行设计的超高压共轨系统喷雾试验平台,开展了超高压共轨系统喷雾特性的试验研究.从油束形态、喷雾贯穿距以及喷雾锥角方面出发,系统定量地分析了喷油压力和喷油规律对船用柴油机喷雾特性的影响,为进一步改善船用柴油机性能提供了理论依据.结果表明：通过控制超高压共轨系统中电控增压器电磁阀和喷油器电磁阀的开启时间,可以实现变压力和变喷油速率喷射;随着喷油压力的升高,油束周围的破碎蒸发现象、喷雾贯穿距以及喷雾锥角均逐渐增大,但当喷油压力超过200 MPa后,其对喷雾贯穿距和喷雾锥角的影响越来越小;随着喷油规律由矩形变化到靴形,油束周围的破碎蒸发现象、喷雾贯穿距以及喷雾锥角均逐渐减小,且喷油压力为150 MPa的矩形喷油规律的喷雾贯穿距大于喷油压力为200 MPa的靴形喷油规律的喷雾贯穿距,这进一步表明了喷射初期的压力是决定喷雾贯穿距的最主要因素.

An experimental study on spray characteristics of ultra high pressure common rail system was conducted based on self-designed spray experimental platform.The effects of fuel injection pressure and fuel injection law on the spray characteristics of marine diesel engine were analyzed in aspects of fuel bundle shape,spray penetration and spray cone angle systemically and quantitatively,which provides theoretical basis for further improve the performance of marine diesel engine.The results show that the variable pressure and fuel injection rate injection can be realized by controlling the opening time of electric-controlled pressure amplifier solenoid valve and injector solenoid valve in ultra high pressure common rail system.With the rise of fuel injection pressure,the fuel bundle break up and evaporation phenomenon,spray penetration as well as spray cone angle all increase gradually,however,when the fuel injection pressure is more than 200 MPa,influence of fuel injection pressure on the spray penetration and spray cone angle becomes smaller and smaller.With the fuel injection law varies from rectangular to saddle-shaped,the fuel bundle break up and evaporation phenomenon,spray penetration as well as spray cone angle all decrease gradually,and the spray penetration of rectangular fuel injection law under 150 MPa fuel injection pressure is larger than that of saddle-shaped fuel injection law under 200 MPa fuel injection pressure,which further indicates that the initial pressure is the most important factor to determine spray penetration.