【摘要】 在考虑进气涡流比的情况下,对某490增压直喷柴油机不同喷油提前角下的缸内喷雾及燃烧过程进行了三维CFD模拟,给出了4种不同喷油提前角时的缸内火焰、NOx和Soot的时空分布。计算和分析了不同的喷油提前角下,上止点前后喷入缸内的油量比例、着火时刻、上止点温度、最高燃烧温度等对燃烧与排放物的影响。结果表明上止点前后的油量比例对排放有较大影响,对于该机型在喷油提前角较小的情况下,应考虑适当减小喷油锥角以充分利用燃烧室底部的空气。仅靠喷油提前角的变化并不能同时降低NOx和Soot的排量,并通过性能与排放试验进行了验证。更多还原

【Abstract】 By using 3-D CFD method,the spray and combustion of a model 490 turbocharged DI diesel engine with different advanced injection angle were simulated.The flame,NOx and soot distribution in cylinder was presented when the engine operated with four different advanced injection angles.The effects of the proportion of fuel injected before and after TDC,temperature at TDC and Max combustion temperature on combustion and exhaust emissions under different advanced injection angle were calculated and analyzed.The results indicate that for this engine the spray cone angle should be decreased when using smaller advanced injection angle,and the NOx and soot emissions can’t be decreased simultaneausly by only varying advanced injection angle.更多还原