高压共轨系统中的燃油温度变化及其影响

Fuel Temperature Change and Its Effect on High Pressure Common Rail System

为说明高压流动燃油温度对喷油量的影响,进行了高压共轨系统中燃油温度变化及其影响研究,建立了燃油不同的发热和热交换数学模型,构建了高压泵、共轨管和喷油器的燃油温度模型,运用液压流体仿真软件AMESim构建高压共轨系统燃油热仿真计算模型;结合试验数据,验证了高压共轨系统燃油热模型的有效性,分析了不同燃油初始温度下不同部件出口燃油温度的变化。在高压泵转速分别为400r/min和1 600r/min时,高压油泵出口温度增加幅度分别约为4.5℃和23.3℃;在共轨管压力从55MPa增大到140MPa时,共轨管出口的燃油温度仅在35℃~55℃之间变化;在共轨压力为140MPa时,喷孔出口温度变化范围在90℃~110℃之间。燃油温度20℃、40℃时的压力变化较小,燃油温度0℃、60℃时的压力变化较大;在低共轨压力时燃油温度引起的喷油量变化大,高共轨压力时燃油温度引起的喷油量变化小。

In order to explain the effect of fuel temperature on fuel injection quantity,fuel temperature change in high pressure common rail（HPCR）system and its effect on the system were studied.A math model of fuel heat release and heat-exchange in HPCR system was founded,a temperature model was built of the fuel in high pressure pump,common rail and electronically controlled injector,and a simulation model of the fuel heat in HPCR system was set up with the hydraulic fluid calculation software AMEsim.The simulation model was verified with the test data.By means of simulation,fuel temperature variation at outlets of different parts was analyzed.The results show at 400 r/min and 1 600 r/min high-pressure pump speed,the fuel temperature at the pump outlet is increased by 4.5℃and 23.3℃respectively;when the rail pressure is increased from 55 MPa to 140 MPa,the change range of fuel temperature at the rail outlet is only35～55 ℃;when the rail pressure is 140 MPa,the change range of fuel temperature at the nozzle orifice outlet is 90～110℃.The pressure fluctuation in the rail resulting from fuel temperature is smaller when the fuel temperature is at 20℃ and 40℃,and larger at 60℃ and 0℃;the fuel injection quantity change due to fuel temperature is larger at low rail pressure and smaller at high rail pressure.