摘要
二冲程航空柴油发动机中,由于柴油粘性大,导致雾化质量较差.改善燃油的雾化质量,能够有效提高冷起动性能.利用GT-Power软件建立了二冲程柴油发动机一维冷起动模型,并校核了模型的准确性;将此模型计算出的压力和温度作为三维仿真模型的边界条件,研究了冷起动不同阶段采用多大的点火提前角、空燃比有利于起动,以及喷油结束时刻、喷油量和燃油温度对起动性能的影响.结果表明:拖动阶段,推迟点火,增加喷油量,有利于形成良好的混合气;起动阶段,较大的点火提前角能够改善起动性能,喷油量较多则会造成燃烧速率减小,不利于起动;稳定阶段和暖机阶段的点火提前角小于起动阶段,能够稳定转速.推迟喷油结束时刻,有利于形成良好的分层混合气;喷油量增大和燃油温度提高,在一定范围内能够改善混合气质量.
Abstract
In two-stroke aviation diesel engines,the atomization quality is poor due to the high viscosity of diesel.Improving the atomization quality of the fuel can effectively improve the cold start performance.The one-dimensional cold start model of the two-stroke diesel engine was established by GT-Power soft-ware,and the accuracy of the model was checked.The pressure and temperature calculated by the model are used as the boundary conditions of the 3D simulation model.The ignition advance angle and the air-fuel ratio that are conducive to starting are studied,and the effects of injection end time,fuel injection volume and fuel temperature on the starting performance are studied in different stages of cold starting.The results show that in the dragging stage,the postponed ignition and the increased fuel injection amount are conducive to the formation of a good mixture.In the starting stage,a larger ignition advance angle can improve the starting performance,while a larger amount of fuel injection will cause the combustion rate to decrease,which is not conducive to starting.The ignition advance angle in the stabilization phase and warm-up phase is smaller than that in the starting phase,which can stabilize the speed.Delaying the end of injection is conducive to the formation of a good stratified mixture;The increase in the amount of fuel injected and the increase in fuel temperature can improve the quality of the mixture.
维普
万方数据