掺混生物柴油对相继增压柴油机燃烧性能的影响

Emission Characteristics of Successively Supercharged Diesel Engine Blended with Biodiesel

为促进生物质能源应用,减轻国家对于化石能源的依赖,以某船用增压柴油机为研究对象,将其改造为相继增压系统柴油机,进行掺混生物柴油燃烧试验,在推进特性25%负荷试验时,生物柴油设置5%~25%共5组配比,研究不同生物柴油配比对柴油机动力性、经济性及排放性的影响.研究结果表明:在25%负荷时,掺混生物柴油燃烧与纯柴油燃烧相比,相继增压柴油机的动力性下降约6.5%,燃油消耗率增长约9.2%,NO_(x)排放量降低约9.8%,SOOT排放量降低约76.7%;相继增压柴油机掺混生物柴油燃烧时,其动力性及排放性均优于原机;在25%负荷时生物柴油最佳掺混率为25%,随着生物柴油配比增加其动力性与经济性下降较快,NO_(x)排放升高,掺混率不宜过高;改造为相继增压船用柴油机后,在一定程度上弥补了掺混生物柴油燃烧带来的不足.

To promote the application of biomass energy and reduce the country’s dependence on fossil energy,a marine turbocharged diesel engine was transformed into a sequential turbocharged system diesel engine,and the combustion test of mixed biodiesel was carried out.When the propulsion characteristic is 25%load,biodiesel is set at 5%-25%in total.Through experiments,the effects of different proportion of Biodiesel on the power,economy and emission of diesel were studied.The results show that at 25%load,compared with pure diesel combustion,the power performance of Sequential Turbocharged Diesel engine is reduced by about 6.5%,the fuel consumption rate is increased by about 9.2%,the NO_(x)emission is reduced by about 9.8%,and the soot emission is reduced by about 76.7%.When the sequential supercharged diesel engine is mixed with biodiesel for combustion,its power performance and emission are better than the original engine.Through the optimization analysis of grey decision theory,the comprehensive optimization shows that the optimal blending rate of biodiesel is 25%at 25%load.With the increase of biodiesel ratio,its power and economy decline rapidly and NO_(x)emission increases,so the blending rate should not be too high.The transformation into a sequential turbocharged marine diesel engine makes up for the shortcomings brought by the combustion of mixed biodiesel to a certain extent.