CTL柴油轿车实际道路的排气颗粒数量及粒径分布

Number and Size Distributions of Particles Emitted by Diesel Car Fuelled with CTL Fuels in Real Road Driving Conditions

研究了柴油轿车燃用煤制油(CTL柴油)的道路瞬态颗粒排放特性,主要研究了其颗粒数量及粒径分布特性。选用3种典型的城市道路类型,包括市区主干道、市区次干道和市区快速路。燃用了纯柴油、纯CTL柴油、其他3种不同掺混配比的CTL柴油混合燃料。研究结果表明:该车实际道路的瞬态排气颗粒数量与车速变化有良好的跟随性。该车燃用各燃料的排气颗粒数量均呈现双峰对数分布。随着车速增加,不论是核态颗粒还是聚集态颗粒,颗粒数量排放率在全粒径范围均持续上升。CTL柴油降低了该轿车的排气核态颗粒和聚集态颗粒数量,尤其是大幅降低了100nm以上聚集态颗粒的数量排放,且随着CTL柴油配比的增加呈现持续降低趋势。随着燃料中CTL柴油配比的增加,这3种道路类型下柴油轿车的排气颗粒总数量均呈现下降趋势,其中市区快速路的下降趋势更为明显。

Transient particle emission from a diesel car fuelled with Coal to Liquids （CTL） fuels driving on three types of typical urban roads were studied, including urban arterial, residential and elevated roads. The fuels used included pure diesel, pure CTL, and three CTL-diesel blends with different ratios. Results show that transient particle emission number of the car on real roads changes closely with the car speed. For all fuels tested, the size distribution of particle number shows bimodal log-normal distribution. Either nucleation mode particle or accumulation mode particle, specific particle number in all size ranges increases with car speed ascending. The CTL component obviously decreases the nucleation and accumulation mode particle numbers at the same time, especially the accumulation mode particles of diameter more than 100 nm,and with adding GTL proportion in the blends the particle number continues to decrease. The total particle number on three types of roads shows downward trends with increasing CTL proportion, especially on the urban arterial road.