城市道路轻型汽油车细颗粒物的排放特性

Fine particle emission characteristics of light-duty gasoline vehicle on urban streets

为研究轻型汽油车在南京市区道路上的细颗粒物排放特征,建立了车载测试系统.通过对比实际道路和底盘测功机测试结果探讨了机动车速度、加速度及行驶工况对细颗粒物排放的影响.实际道路下,加速状态下的车辆颗粒物数量、质量浓度明显高于其他行驶状态;在低速情况下,核模态(Dp<50 nm)细颗粒物数量浓度较大,高速条件下积聚模态(50 nm<Dp<565 nm)的颗粒数量较多.底盘测功机试验的颗粒物平均数量浓度为车载试验下的1.62倍,但质量浓度仅为车载试验的0.18倍.粒径100 nm以下的细颗粒物数浓度占整个测试的绝大部分.高速及急加速下,车辆会产生更多细颗粒物.结果表明:实际道路轻型汽油车的细颗粒物排放特性可用该车载系统来描述.

To investigate the fine particle emission instantaneous characteristics of a single light-duty gasoline vehicle on Nanjing urban streets, an on-road system of chassis dynamometer was set up to ana- lyze the influences of vehicle speed, acceleration and driving modes on fine particles size distributions. For the on-road measurements, the number and the mass concentration of particles under acceleration condition are obviously higher than those under other driving modes. At low speed, the number concen- tration of fine particle in nucleic mode（Dp 〈 50 ran） is higher than that at high speed, while the particle numbers in accumulation mode（50 nm 〈 Dp 〈 565 nm） at high speed is more than that at low speed. The average total number concentration in the chassis dynamometer tests is 1.62 times than that in on-road measurements, while the ratio of average mass concentration to that in on-road measurements is only 0.18. The particle number concentration with diameter lower than 100 nm accounts for a vast majority of the test range. More fine particles are emitted under high speed and hard acceleration condition. The re- suhs show that the proposed system is effective to investigate the fine particle emission characteristics from a light-duty gasoline vehicle at real urban road.