不同喷油模式下柴油机可用能分析的试验研究

通过台架试验的方法,对1台0.5L单缸柴油机进行了热力学分析,将缸内燃烧所释放能量的热量分布和可用能分布进行计算和比较,在此基础之上比较了喷油规律相关参数对热平衡的影响,提出了相应减少不可逆损失、提升热效率的解决途径。试验结果表明:在相同工况下,对于不同的喷油模式,燃烧不可逆损失差异不大,差异主要体现在排气损失和其他部分损失;预喷参数和后喷参数对热量分布影响较小,而喷油压力和主喷正时的影响较为明显。随着喷油压力的增大或主喷正时的提前,燃烧不可逆程度降低,排气可用能损失减少,热力循环的热效率得以提升。而对于余热能回收,排气中流失的可用能回收的潜力和价值较大,将这一部分能量妥善地利用可对整机性能起到明显的改善效果,若排气温度从750K降至500K,通过排气余热能的利用可提升指示功20.91%,达到提升动力性和燃油经济性的目的。

Experimental Investigation on Exergy Analysis of Diesel Engine under Different Injection Modes

The released heat and exergy distribution of in-cylinder combustion were calculated and compared through the bench test method based on the thermodynamic analysis of a 0.5 L single cylinder diesel engine.The effects of injection related parameters on thermal equilibrium were further analyzed and the solution to improve thermal efficiency and reduce irreversible loss was provided.The results show that the irreversible loss of combustion between different injection modes has little difference except for the loss of exhaust and other parts.The pre-injection and post-injection parameters have little influence on thermal distribution, but the injection pressure and main injection timing have the opposite result.With the increase of injection pressure or the advance of main injection timing, the irreversible loss of combustion process and exhaust gas exergy loss decrease and thermal efficiency improve.As for the recovery of waste heat, the exhaust has such a great potential that the engine performance can improve significantly.The indicated power will improve by 20.91% when the recovered energy of exhaust temperature decreases from 750 to 500 K, achieving the goal of power output and fuel economy improvement.