车用燃料电池系统阳极排气特性研究

Study on Anode Exhaust Characteristics of Vehicular Fuel Cell System

基于阳极再循环模式,建立62kW车用燃料电池系统氢气系统集总参数模型。根据不同排放持续时间和排放周期制定8种排放策略,研究不同排放策略下阳极的进气流量、压力、引射器引射比和比例阀开度的变化规律。结果表明:在阳极脉冲排放过程中,排放持续时间从0.25s增至1.00s时,阳极气体流量、进气压力变化增幅均超过85%,但随着排放持续时间逐渐延长变化增幅逐渐趋于平缓;同时当排放持续时间延长,由于膜的湿润度降低,引射器引射比波动范围增大73.7%,且比例阀开度也会增大,但高频次、长时间排放会造成氢气的浪费,同时对比例阀等机械零件的寿命和精度有损害。因此在保证良好水管理的前提下,短时、长周期的排放策略有利于电堆高效运行。

Based on hydrogen recirculation,a lumped parameter model of hydrogen subsystem of 62kW in vehicular fuel cell system is established.According to different purge durations and purge cycles,eight purge strategies are developed and the influences of purge strategy on inlet flow rate,inlet pressure,ejector ratio and proportional valve opening are studied.The results show that during the process of anode pulse discharge,when the discharge duration increases from 0.25sto 1.00s,the fluctuation of anode gas flow and inlet pressure increase by more than 85%,but the changes tend to be gradual with the increase of discharge duration.At the same time,when the purge duration is prolonged,the fluctuation range of the ejector ratio will increase by 73.7%due to the reduction of the wetness of the membrane,and the opening of the proportional valve will also increase.However,gas purge with high frequency and long duration will cause the waste of hydrogen and the damage of mechanical parts such as proportional valves in the precision and life.Therefore,on the premise of ensuring well water management,the short-time and long-period purge strategy is beneficial for the efficient operation of the fuel cell.