用于混合动力汽车的球形发动机热力学过程分析

作为混合动力汽车增程系统的一种新型动力源，球形发动机有着功率密度高，结构紧凑等优点。在介绍球形发动机工作原理及基本结构的基础之上，研究了发动机气缸容积变化规律，分析发动机燃烧过程，建立了发动机热力学理论模型。利用FLUENT开展了仿真研究，验证了模型的正确性，进而对于发动机燃油喷射过程进行了分析。结果表明：计算得到的气缸内部温度与压力曲线与仿真得到的结果基本一致，验证了理论模型的正确性。在燃油喷射的过程中，可能会出现涡团状的燃油喷射轨迹，使得局部富油发生，燃烧性能变差。

Thermodynamic process of sphere cam engine applied in HEVs

As a new kind of power source of extend range system applied in Hybrid Electrical Vehicles(HEVs), sphere cam engine is said to have high power density and compacted structure. Based on the introduction of working principle and structure of sphere cam engine, the variation of cylinder volume is studied. Furthermore, the combustion process of sphere cam engine is analyzed to establish the theory thermodynamic model of engine. Then the theory model is validated by simulation of thermodynamic process of engine using FLUENT. The oil spray process is simulated using the CFD model. Results show that the calculated pressure curve and temperature curve in cylinder are similar to the simulation results. The comparison results validate the theory model. However the vortex of sprayed oil may lead to the rich oil phenomena, which may decrease the combustion efficiency.