混合比对正丁醇/柴油混合燃料HCCI发动机燃烧特性的影响

摘要

The effects of blending ratio on combustion characteristics of HCCI engine fuelled with n-bu-tanol/diesel blends were conducted on a modified water-cooled,naturally aspirated and double-cylinders diesel engine.The cylinder pressure,rate of pressure rise,heat release rate,cylinder temperature,cycle-to-cycle variations (CCV)and indicted thermal efficiency were compared and analyzed by bench tests under the conditions with different blending ratio at engine speed of 1 000 r/min,excess air coefficient of 2.5 and intake temperature of 140 ℃.The experiment results showed that the blending ratio had great effects on combustion characteristics of n-butanol/diesel blends HCCI engine.The peak cylinder pressure,peak rate of pressure rise,maximum heat release rate increased firstly and then decreased with the increasing of blending ratio,and their corresponding crank angle moved backward.And with the increasing of blending ratio,the cylinder temperature increased,the variation coefficient of peak pressure decreased firstly and then raised,and the indicted thermal efficiency increased but not significantly.%以1台水冷、自然吸气双缸柴油机的2#缸改造成的 HCCI 发动机为试验对象，研究混合比对正丁醇/柴油混合燃料 HCCI发动机燃烧特性的影响.利用发动机台架，采用不同混合比燃料依次进行试验，对比分析了正丁醇/柴油混合燃料 HCCI发动机在转速为1000 r/min、过量空气系数为2.5、进气温度为140℃下的缸内压力、压力升高率、燃烧放热率、缸内温度、循环变动系数等参数.结果表明：混合比对 HCCI 发动机燃烧特性影响很大；随混合比升高，峰值缸内压力、峰值压力升高率和最大燃烧放热率先升高后降低且峰值出现时刻滞后；缸内温度下降，峰值压力循环变动系数先降低后升高，指示热效率升高但不显著.