液压自由活塞发动机起动过程的实验研究

为研究液压自由活塞发动机（HFPE）的起动性能，对HFPE样机的典型起动方式进行了实验研究.根据HFPE的起动能源和激励方式的不同，给出了恒压阀控、恒压位控、起动蓄能器（SHA）阀控以及SHA位控四种起动方式.测试了恒压起动方式中活塞组件的位移特性、扫气腔压差、动力腔压差以及HFPE泵腔压差这4个起动性能参数随供油压力变化的曲线，分析了SHA方式下上述四个起动性能参数分别和初始蓄能压力的关系.讨论了四种起动方式在激励方式、能量补充方面的差别.结果表明，位控起动的起动性能较阀控方式优良，适宜用于工作功率较高的场合，而阀控方式只能用在一些中低起动频率场合中.

Study on starting phase of hydraulic free piston engine

To study the starting performance of hydraulic free piston engine(HFPE),the typical starting phases of HFPE were investigated through experiments.According to different starting energy sources and excitement modes in HFPE,4 starting modes of constant pressure valve control,constant pressure position control,starting hydraulic accumulator(SHA) valve control and SHA position control were given.With the change in supply-oil pressure,4 starting performance parameter curves including displacement of the piston assembly,the pressure difference in scavenging chambers,the pressure difference in combustion chambers and the one in the hydraulic chambers of the pump were tested in constant pressure starting mode.The relationship of the 4 parameters above-mentioned and initial accumulated pressure were analyzed in the SHA starting mode.The differences among 4 starting modes on excitement method and energy supplement were discussed.Results show that the position-control mode has better starting performance than valve-control mode,and is suitable for a higher power occasion.Valve-control mode is applicable to a case with lower starting-frequency.