中文摘要：

介绍了液压自由活塞发动机的三种基本结构、工作原理和优点,重点分析了液压自由活塞发动机由于其独特的结构所具有的特性、研制过程中的关键技术、研究难点,以及相应的研究现状,讨论了制约液压自由活塞发动机走向产业化的瓶颈技术,以及为解决这些技术所进行的探索和尝试。推动液压自由活塞发动机的发展可从结构改进、燃料及燃烧技术突破及多学科融合技术等方面进行。

英文摘要：

Three basic configurations of HFPE,their working principles and merits were introduced.Special characteristics of HFPE due to the unique structure,key technologies and challenges in developing,and research situation of HFPE were discussed in detail.The bottleneck techniques which restricted the industrialization of HFPE were pointed out.The exploration and tries to solve these bottleneck techniques were introduced.Development of HFPE might be carried out through the improved structure,the breakthrough of combustion and fuel technology,and the multidisciplinary integration.