考虑摩擦时Otto循环功率效率特性新析

New Solutions of Power and Efficiency for Otto Cycles with Friction

对有摩擦时的 Otto循环进行了有限时间热力学分析。建立了一种新的模型 ,以循环的活塞平均速度和摩擦系数为基准求得了摩擦损失功率以及功率和压缩比、效率和压缩比的关系 ,进而得到了功率与效率关系 ,并进行了计算和讨论。结果表明 ,与实际热机循环的性能特性一致。

The Otto engine cycles are investigated by finite time thermodynamics in this paper.The new model for the cycles is established.The loss cycle power by friction is calculated on the bases of the average cycle piston velocity and related friction coefficient.The new relations between power and compression ratio and between efficiency and compression ratio are derived,by which the new relation between power and efficiency can be obtained.These relations are discussed.It is shown that the loop shaped power versus efficiency curves are similar to real heat engine characteristics.Finally,comparing the results with related results in published literature,some useful conclusions are drawn.