Simulation of the Effect of Fuel Injection Rate that Matches Fuel Injection Advanced Angle on the Performance of Ultra High Pressure Common Rail Diesel Engine

喷油速率匹配喷油提前角对超高压共轨柴油机性能影响的仿真研究

¹ College of Power Engineering, Naval University of Engineering, Wuhan 430033, China
² Automobile NCO Academy, Army Military Transportation University, Bengbu 233011, China

^* 杨昆(1981-), 海军工程大学副教授, 主要从事内燃机测试及电控技术研究。 E-mail:150006224@qq.com

Received: 1 April 2018

Abstract

On the basis of introducing the implementation method of variable fuel injection rate, the calculation model of a single-cylinder ultra high pressure common rail diesel engine was built, and the accuracy of this model was verified with experiments; then the effects of different fuel injection rates and fuel injection advanced angles on the performance of the ultra high pressure common rail diesel engine were analyzed with this model. The results show that the variable fuel injection rate can be realized by adjusting the opening time of electric-controlled pressure amplifier and injector solenoid valve in the ultra high pressure common rail system. With the lagging of pressurization time, the cylinder pressure, cylinder temperature, heat release rate and NO_x emissions of the diesel engine decrease, while the soot emission rises. The ultra high pressure rectangle injection rate can make the diesel engine acquire best power and economy performance. With the increasing of fuel injection advanced angle, the cylinder pressure, cylinder temperature, heat release rate and NO_x emission of the diesel engine rise, while the soot emission decreases first and then rises, the too small or too large fuel injection advanced angle can both reduce the power and economy performance of the diesel engine. The high fuel injection rate that matches small fuel injection advanced angle can improve power output and reduce fuel consumption of the diesel engine, and there is an optimal fuel injection advanced angle for each fuel injection rate to make the diesel engine performance achieve the best.

摘要

在介绍可变喷油速率实现方法的基础上，建立了单缸超高压共轨柴油机的计算模型，并利用试验验证了模型的准确性，而后通过模型分析了不同喷油速率和喷油提前角对超高压共轨柴油机性能的影响。结果表明：通过调整超高压共轨系统中电控增压器和喷油器电磁阀的开启时间，可以实现喷油速率的柔性可调；随着增压时间的滞后，柴油机缸压、缸温、放热率以及NO_x排放均下降，而soot排放上升。超高压矩形喷油速率可使柴油机获得最好的动力性和经济性。随着喷油提前角的增加，柴油机缸压、缸温、放热率以及NO_x排放均上升，而soot排放先下降后上升，太小或太大的喷油提前角都会降低柴油机的动力性和经济性。高喷油速率方案匹配较小的喷油提前角能提升柴油机的动力输出并降低燃油消耗，且每种喷油速率都存在一个最优的喷油提前角，使柴油机性能达到最佳。