燃油品质对柴油机燃烧循环变动特性及性能的影响

摘要

The effects of diesel on combustion cyclic variation and engine performance index under different speeds and loads were researched by combusting three kinds of diesel .The results show that the cyclic variations of peak cylinder pressure and pressure rise ratio decrease with the speed increase at full load speed characteristic .Moreover ,the variation rates of peak cylin‐der pressure and pressure rise ratio are larger at lower load of the same speed .With the decrease of cetane number and first dis‐tillation temperature ,the ignition delay time becomes longer , the percent of light distillation composition and the required amountof premixed combustion increases .Finally ,the in‐cylinder combustion and pressure rise accelerate ,the variation rates of peak cylinder pressure and pressure rise ratio increase ,the corresponding combustion process becomes short tempered and so the realized power and fuel economy deteriorate .%燃用3种柴油进行了柴油机性能试验，研究了不同转速和负荷下柴油对燃烧循环变动特性及柴油机性能指标的影响。研究表明：在全负荷速度特性下，随着转速的升高，最高燃烧压力和最大压力升高率的循环变动率逐渐减小；相同转速下，负荷越小，最高燃烧压力和最大压力升高率的循环变动率越大；燃油的十六烷值越小，其自燃性越差，着火滞燃期越长；初馏温度较低时，轻馏分含量较高，参加预混合燃烧的份额大，容易造成燃烧速度加快，压力升高速度快，导致最高燃烧压力和最大压力升高率的循环变动率变大，对应燃烧过程变粗暴，由此实现的动力性能和经济性能变差。