摘要:
Taking a diesel engine equipped with a high pressure common rail system as the research object,using fluid dynamics simulation software FLUENT,the influence of the change of pilot injection parameters on engine emission performance and the variation of flow field in cylinder were studied.The results show that in a certain amount of pilot injection,with the pilot injection and the main injection interval angle increases,the pilot injection fuel combustion starts earlier,the time about the cylinder pressure reaching the peak is earlier,the emission of NO is lower,and the soot emissions increases first and then decreases.When fixed the interval angle of pilot injection and the main injection,with the increase of pilot injection quantities,the faster the cylinder pressure elevated,the more heat is released,the higher the NO emissions is,the emission of Soot increases first and then decreases.%以高压共轨系统柴油机为研究对象,利用流体动力学仿真软件FLUENT,研究了喷射参数变化对发动机的排放性能和缸内流场的变化规律.结果表明:在一定的预喷油量下,随着预喷射和主喷射间隔角的增加,预喷射燃油燃烧开始较早,缸内压力升到峰值的时间越早,NO的排放量越低.在固定喷射和主喷油的间隔角时,随着预喷射量的增加,气缸压力升高的速度越快,释放的热量越多,NO排放越高,Soot排放量则会先增加,然后减少.