滑片泵在二甲醚发动机共轨燃料系统低压回路中的应用

Application of sliding vane pump in low pressure loop for DME engine

二甲醚发动机中,利用高压氮气罐可克服共轨燃料系统低压回路中产生的气阻,但其本身因体积较大等不利于小型化车载应用。本文提出用滑片泵替代高压氮气罐作为加压装置,并运用AMESim进行仿真,模拟滑片泵在低压回路中的工作过程,确定其合理的参数。仿真结果表明,采用滑片泵作为加压装置,当取吸油区窗口幅角为（45°~155°）、压油区窗口幅角为（230°~324°）时,该滑片泵单个腔体输入压力可保持在0.5 MPa之上,峰值输出压力为2MPa,满足二甲醚发动机共轨燃料系统低压回路对供油压力的要求;输出流量的频率随转子转速的增大而变高,而与偏心距大小无关;增大滑片泵转子转速和偏心距均可有效增大滑片泵输出流量及其波动幅度;该滑片泵的偏心距为1.5mm、转速为400 r/min时,其输出流量更接近所需最大供油量4.56L/min,且波动幅度较小。

High pressure nitrogen gas tank used in dimethyl ether（DME）engine can eliminate air resistance in the low pressure loop;however,its large size is not conducive to miniaturization in automotive applications.In this study,the sliding vane pump was adopted as the pressure device instead of nitrogen tank.By using AMESim software,the working process of the sliding vane pump in the low pressure loop was simulated.The simulation results show that as a pressure device,the input pressure of a single chamber of the sliding vane pump can be kept above 0.5MPa and the output peak pressure at 2 MPa by setting suction area window angle at（45°~155°）and the delivery area window angle at（230°~324°）,which satisfies the requirement of the low pressure loop of DME common rail fuel system in oil supply pressure.The frequency of the output flow goes higher along with the increase of rotor speed yet it is not influenced by the eccentricity.By increasing the rotor rotating speed or eccentricity of the sliding vane pump,the flow rate and flow fluctuation of the sliding vane pump will significantly rise.When the eccentricity is 1.5mm and the speed 400r/min,the output flow of the sliding vane pump is closer to the largest required flow 4.56L/min with less volatility.