柴油机过量空气系数的防熄火要求

Requirements for the Excess Air Coefficient to Avoid Flameout in Diesel Engine

柴油机这一当前应用最广泛的重要动力装置,往往由于过量空气系数降低而影响动力性能甚至直接熄火。本文根据柴油机过量空气系数与其平均有效压力、排气平均温度等主要参数的关系,基于缸内燃料燃烧过程的热力学计算,对柴油机过量空气系数的防熄火要求进行分析,给出了柴油机防熄火的临界过量空气系数理论值求解方法,从而在理论上进一步阐述了随着过量空气系数的降低,柴油机的动力性降低、热负荷增加、燃烧质量下降的现象;特别是当过量空气系数低于临界值时,柴油机会熄火,无法维持正常工作。所得结论对柴油机理论与应用的深入研究,提高其在各种不同条件下工作的可靠性具有实际意义。

As the most widely used and important power plant at present, due to the decrease of excess air coefficient (EAC), the dynamic performance of diesel engine often receives great influence even direct flameout. According to the relationship between EAC and main parameters such as mean effective pressure and mean exhaust temperature, based on the thermodynamic calculation about fuel combustion process in cylinder, this paper analyses the requirements for the EAC to avoid flameout in diesel engine and provides the method of calculating the critical EAC, and thus we can give further elaboration to the phenomenon that with the loss of EAC, the power performance re-duces, the thermal load increases and the combustion quality reduces in theory;especially when EAC is less than the critical value, the diesel engine will face flameout and can’t maintain normal work. The conclusion has practical significance to the further study of diesel engine theory and application, the reliability increase under all kinds of different conditions.