GTL添加比例对高压共轨柴油机微粒排放粒度分布的影响

Effect of GTL Ratio on Particle Size Distribution in Common-Rail Diesel Engine

针对高压共轨增压中冷柴油机燃用不同添加比例的GTL/柴油混合燃料微粒排放进行了试验研究,分析了天然气合成油(GTL)添加比例对柴油机稳态工况及不同瞬变率的恒转速增转矩瞬态工况微粒排放粒度分布的影响规律,揭示了稳态及瞬态工况微粒排放粒度分布的差异.结果表明,对于不同GTL添加比例的混合燃料、最大转矩对应转速(1,600,r/min)下,微粒数量浓度分布曲线均呈单峰结构,峰值粒径位于50～100,nm.与燃用石化柴油相比,对稳态工况、在中小负荷时燃用适当GTL添加比例的混合燃料能够降低总微粒及核态微粒数量浓度,随GTL添加比例增大则总微粒及核态微粒数量增加;在大负荷工况下,燃用GTL/柴油混合燃料时总微粒及核态微粒数量浓度降低效果不明显,积聚态微粒数量浓度则随GTL添加比例增大而增加.等空燃比瞬态工况下不同模态微粒数量浓度均高于对应稳态工况,但随GTL添加比例的增加,有助于降低瞬态工况总微粒及核态微粒排放数量.

An experimental investigation on the effects of GTL-diesel blends on particulate emission in a turbocharged/intercooled common-rail direct injection（CRDI）engine under steady cycles and transient cycles was conducted.Particle size distribution was also measured.Result shows that particle size distribution of transient cycle is different to that of steady cycle.Particle size distribution of GTL-diesel blends shows unimodel with its peak at 50—100,nm at 1,600,r/min（speed at maximum torque）.Under low and middle loads,proper addition of GTL can reduce total particle number and nucleation mode particle number compared with diesel,but the increase of GTL proportion in blend,total particle number and nucleation mode particle number are increased.Under high load,addition of GTL does not reduce the nucleation mode particle number obviously.However,accumulation mode particle number is increased with the increase of GTL in blend.At same air-fuel ratio,the nucleation mode particle number and accumulation mode particle number are lower than those of transient cycles.Total particle number and nucleation mode particle number are increased with GTL addition under transient cycle.