直喷式柴油机燃用生物柴油-正丁醇混合燃料时的性能与排放

Performance and emissions of a direct injection diesel engine operating on biodiesel-n-butanol blends

为了研究掺入正丁醇对柴油机燃用生物柴油时性能与排放的影响,测量了正丁醇质量分数分别为0、10%、20%和30%的生物柴油-正丁醇混合燃料的理化特性,并通过发动机台架试验,研究了混合燃料的燃烧与排放特性。研究结果表明:生物柴油-正丁醇混合燃料的密度、粘度、表面张力、十六烷值和低热值随着正丁醇比例的增加而减小,掺入30%正丁醇时,其粘度可减小39.3%;随着正丁醇比例的增加,混合燃料的喷油延迟角、滞燃期和预混燃烧放热率峰值增加,而缸内燃烧温度和压力峰值降低,燃烧持续期缩短,有效热效率增加;与柴油相比,生物柴油的碳烟、CO和HC排放较低,NO_x排放较高;随着正丁醇比例的增加,混合燃料的NO_x、碳烟和CO排放降低,HC排放升高,掺入10%正丁醇时NO_x排放低于柴油。

In order to study the effect of n-butanol addition to biodiesel on engine performance and emissions,the physical and chemical properties of biodiesel-n-butanol blends with 0,10%,20%and 30% n-butanol by mass fraction were evaluated.Then the combustion and emission characteristics of the biodiesel-n-butanol blends were investigated by the engine dais experiment.The results show that the density,viscosity,surface tension,cetane number and lower heating value of the biodiesel-n-butanol blends decrease with the increase of n-butanol mass fraction,and the viscosity of the blends with 30% n-butanol can be reduced by 39.3%.For the biodiesel-nbutanol blends,the fuel injection delay,ignition delay and peak heat release rate increase,the maximum in-cylinder pressure and combustion temperature decrease,the combustion duration shortens and the effective thermal efficiency increases with the increase of n-butanol content in the blends.Smoke,CO and HC emissions of biodiesel are lower,while NO_x emissions are higher than those of diesel.NO_x,smoke and CO emissions of the blends reduce,but HC emissionsincrease with the increase of n-butanol content.NO_x emissions of the blends with 10% n-butanol are lower than diesel.