发动机燃用GTL柴油的排气颗粒数量及粒径分布规律

以一台汽车电控高压共轨柴油机为样机,采用发动机尾气颗粒粒径谱仪EEPS研究了发动机燃用天然气制油(GTL柴油)的排气颗粒数量及粒径分布规律.所用燃油分别为纯柴油(G0)、纯GTL柴油(G100)及GTL柴油掺混比为10%、20%的燃料(分别表示为G10、G20).试验工况为最大转矩转速1500r.min-1和标定转速2300r.min-1的负荷特性试验,负荷百分比分别为10%、25%、50%、75%和100%.结果表明:无论燃用柴油,还是GTL柴油或混合燃料,该机排气颗粒数量随粒径变化大都呈现明显的双峰对数分布状态,其排气核态颗粒的峰值粒径在10nm附近,聚集态颗粒峰值集中出现在40～50nm之间.随着GTL柴油配比的增加,各工况下不同粒径的颗粒数量大都持续下降,其中,排气核态颗粒数量明显下降,在高速高负荷下更为显著;而聚集态颗粒也较纯柴油有一定的降幅,其中,G20和G100柴油更为明显.

Exhaust particle number and size distribution from a diesel engine with gas-to-liquids fuel

Exhaust particle number and size distribution of an electronic control high-pressure common-rail diesel engine, fueled with gas-to-liquids (GTL), are studied by an Engine Exhaust Particle Sizer (EEPS). The fuels are pure diesel fuel (G0), pure GTL fuel (G100), G10 and G20 with GTL blend ratios of 10% and 20%. Two typical engine speeds of 1500 r·min^-1 and 2300 r·min^-1 are tested, with the load ratios of 10%, 25%, 50%, 75% and 100%, respectively. The results show the size distribution of particle number from the engine has clear bimodal logarithmic distribution, with a nucleation mode peak value around 10nm particle diameter, and an accumulation mode peak value in 40 nm to 50 nm particle diameter. With the increasing blend ratio of GTL fuel, the number of nucleation mode particles decreases significantly, and has greater decline at high speed engine operating conditions. The number of accumulation mode particles of GTL fuel drops clearly than pure diesel fuel, especially G20 and G100.