中文摘要：

液压约束活塞发动机（HCPE）是一种将燃料在缸内燃烧产生的热能直接转化为流体压力能的新型动力装置，运转平稳性是其设计分析和性能评价的重要依据。论述了轴向HCPE的工作原理，给出了运转不均匀度的定义，建立了单缸轴向HCPE工作过程的动力学微分方程，求解出各系统变量的时间历程，直接利用概念计算系统运转不均匀度，避免了传统方法中盈亏功的确定，便于进行相关研究。HCPE运转不均匀度比具有对应结构的活塞式内燃机驱动柱塞泵系统全工况改善4．7％～15．6％。

英文摘要：

Hydraulic confined piston engine （HCPE） is a new type of power system to transform the thermal energy from fuel combustion in cylinder into hydraulic energy directly. Its running stability is an important basis of design analysis and performance evaluation. Its working principle was discussed and the definition of its running unevenness was given. The dynamic differential equations of working process of single--cylinder axial HCPE were constructed, from which some system variables＇ time courses were solved, so its running unevenness can be computed by the definition, which avoids the solution of break--even work, all above is useful for farther related study. The running unevenness of HCPE improves by 4.7%～15.6% than piston type internal combustion engine with corresponding structure under total working conditions.