改进散热模型在斜盘发动机缸内热力过程仿真中的应用

Applied research on improved heat release model for in-cylinder thermodynamic process simulation of swash-plate engine

为研究不同散热模型对斜盘发动机缸内热力过程的影响,改进了缸内工质原有的一点平均温度散热模型,得到了三点平均温度模型和考虑缸套内壁面轴向温差散热模型,使最终的散热模型同时考虑了活塞周期性覆盖的影响以及缸套内壁面的轴向温差。以发动机热效率为参照依据,结合缸内工质热力学数学模型对不同散热模型下某型斜盘发动机缸内热力过程进行了仿真。仿真结果表明:工质散热模型主要影响缸内工质的温度和散热量,而对缸内压力影响较小;改进后的散热模型能够较好反映缸内工质的散热规律,可使斜盘发动机缸内热力过程仿真更接近实际情况。

To analyze the effect of different heat release models on the in-cylinder thermodynamic process of swash-plate engine, this paper makes an improvement on the original one-point mean temperature heat release model and obtains the three-point mean temperature heat release model and the one with axial temperature difference in the in-cylinder wall. And the final heat release model of wor- king substance takes into account the effect of cyclic reciprocating piston and the axial temperature difference of the in-cylinder wall. The in-cylinder working process of a swash-plate engine with different heat release models is simulated by use of the thermodynamics model of working substance according to the standard of thermal efficiency of engine. The results show that the heat release model has a significant effect on the temperature and heat-release quantity of in-cylinder working substance but a small effect on in-cylinder pressure. The improved heat release model can meet with the heatrelease condition of in-cylinder working substance so as to make the in-cylinder working process simu- lation of swash-plate engine closer to reality.