Pressure of nozzle volume is very important for injection system.The designed measurement system can accurately measure the pressure of nozzle volume in electric solenoid common-rail system.Pressure curve obtained can well reflect the pressure variation,and provides accurate pressure boundary condition for flow analysis and spray simulation.Results show that the pressure of nozzle volume equals to the common rail pressure at no injection,but will fluctuate when the needle moves up,and its fluctuation magnitude depends on the pressure of common-rail.Maximum variation is 20%.Nozzle volume still has significant pressure fluctuation after the needle closes,and the fluctuation will affect after-injection control in multi injection.Based on pressure curve of nozzle volume,the time response of solenoid,the delay of opening and closing of needle and injection duration can be calculated.Pressure curve can also reflect the needle movement.Measurement of nozzle volume pressure and needle lift will provide boundary condition for injector design and calculation in the future.%喷油器盛油槽的压力非常重要,设计的测量系统能够准确地测量盛油槽压力,测得的结果客观地反映了盛油槽的压力变化趋势,为燃油在油嘴内的流动分析和喷雾特性计算提供边界条件.在不喷射的稳态情况下盛油槽与共轨管内压力相同,但在针阀打开后的喷油过程中,盛油槽压力是波动的,降低或升高的最大幅值与轨压有关,但最大幅度基本相同,为轨压的20%.喷油结束后,盛油槽内仍存在巨大的压力波动,该波动将影响多次喷射中后喷射的控制.盛油槽压力曲线在喷油过程中存在有规律的波动,根据该压力变动过程可以分析出电磁铁的响应时间、针阀的开启和关闭延迟,并计算出实际的喷油持续期.压力曲线还可以从侧面反映针阀运动情况,盛油槽压力与控制腔的压力和针阀升程联合测量,将为喷油器设计和喷雾计算提供更为系统的边界条件,但鉴于其难度,需要逐步实现.
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