一种新的燃油喷射模型及其在直喷汽油机开发过程中的应用

A New Fuel Injection Model and Its Application in the Development Process of Gasoline Direct Injection Engine

直喷汽油机的开发对于缸内喷雾精确性要求较高,商业软件自带的模型在喷雾形状和模拟准确度方面存在着很大的不足.针对这一现状,利用STAR-CD软件平台,采用Fortran语言编写了适用于直喷汽油机的程序代码,并进行了定容环境下喷雾形状的对比,两者具有较高的一致性.在油粒分裂、破碎过程中,油束分布和实际物理过程更加吻合,而喷雾的贯穿距离,试验和CFD分析基本吻合,误差均在5%以内,说明该模型有很好的计算精度.随后,在2.0,L增压直喷汽油机的开发过程中,应用该程序进行了缸内瞬态过程的数值分析,并对制造样机进行了试验验证.结果表明,该喷雾模型结合ECFM燃烧模型可以较准确地预测缸内油气混合及燃烧状况,能够很好地支持工程开发.

The development of GDI engine needs higher accurate information of the in-cylinder spray.However,the commercial software has some shortages in spray shape and stimulation accuracy.In this work,the subroutines with FORTRAN language were written which is suitable to the GDI engine based on the STAR-CD software platform.It gives good prediction on the spray shape under constant volume situation.Results show that the gradient distribution of spray is formed during the split and breakup progress which is in good agreement with the actual physical progress.The measured spray penetration distance is consistent with the CFD prediction.The numerical transient analysis in-cylinder is conducted using this code in the development process of a 2.0,L GDI engine,and then the test is validated by manufacturing prototype.Results show that the spray model combined ECFM combustion model can accurately predict the fuel mixture and combustion in-cylinder and support the engineering development.