柴油机燃用F-T柴油与0号柴油混合燃料的燃烧特性

根据实测的喷油器针阀升程和示功图,开展了直喷式柴油机燃用F-T柴油与0号柴油混合燃料时燃烧特性的研究．试验用燃料为0号柴油、含25%和50%F-T柴油的混合燃料以及100%F-T柴油．结果表明,在相同工况下,随着混合燃料中F-T柴油比例的增加,喷油延迟角增大,而喷油持续期变化不大．滞燃期随着F-T柴油比例的增加而缩短,其中当F-T柴油的比例由0增至25%时,滞燃期缩短最为明显,此后进一步增加F-T柴油的比例,滞燃期缩短幅度减小．随着混合燃料中F-T柴油比例的增加,预混燃烧放热峰值降低,扩散燃烧放热峰值增大,燃烧持续期略有延长,缸内最高燃烧压力和气体最高平均温度降低,最大压力升高率显著下降,发动机的燃烧噪音和机械损失减小,有效燃油消耗率和有效热效率得到改善．

Combustion Characteristics of Direct Injection Diesel Engine Operating on Blends of No.0 Diesel and Fischer-Tropsch Diesel

On the basis of the recorded in-cylinder pressures and injector needle lifts,the combustion characteristics of a single-cylinder direct injection diesel engine operating on blends of Fischer-Tropsch (F-T) diesel and No.0 diesel fuels were investigated.The four test fuels are blends containing 0,25% and 50% by volume of the F-T diesel and 100% F-T diesel respectively.The results show that the fuel injection delay increases while the injection duration varies little with in- crease in the F-T diesel addition at the same speed-load point;ignition delay decreases with increase in the F-T diesel addi- tion,which is the greatest when the blending ratio of F-T diesel reaches 25%,and then the decreasing level decreases with a further increase of F-T diesel fraction;the peak value of premixed burning rate decreases while the maximum diffusive burning rate increases with the increase of F-T diesel fraction in the blends;the combustion duration slightly increases with increase in the F-T diesel addition;maximum cylinder gas pressure and maximum mean gas temperature decrease,and the maximum rate of pressure rise drops remarkably with increase in the F-T diesel addition;the increase of F-T diesel fraction in the blends results in the decrease of mechanical load and combustion noise;in addition,the brake specific fuel consump- tion decreases and the effective thermal efficiency increases with increase in the F-T diesel addition.