增压柴油机排气提前角与指示功关系的分析

Analysis of Interrelation between Advance Angle for Exhausting and Indicated Power of Turbo-charged Diesel

排气提前角对增压柴油机输出功的影响较为复杂 ,主要影响了柴油机的排气损失、涡轮功、增压压力和扫气压差等 ,本文对此作了综合的分析。本文还推导出考虑了排气提前角和泵气功在内的指示功的计算公式 ,并应用该公式 ,分析了排气提前角θ对指示功wi 以及dwi/dθ的综合影响 ,得出了存在着一个有利排气提前角使指示功最大的结论。

In a turbo-charged diesel,the advance angle of exhaust valve opening θ has complex influence on power output,exhaust loss,power and pressure of turbocharger,and scavenging pressure difference.In this article,a comprehensive analysis of the influence is carried out,and a calculation equation of the indicated work,in which the advance angle and pumping work are considered,is deduced.By using the equation,the influence of the advance angle on the indicated work W i and dW i/dθ is discussed.The analysis comes to a conclusion that there is a favorable advance angle,with which a maximum indicated work can be obtained.