限行对LPG公交车工况影响与减排效果

Effect of traffic control on operating conditions and exhaust emissions of LPG buses

以大型LPG公交车为对象,研究广州市限行措施对车辆运行工况及排放的影响。采用车载排放测试实时测试亚运限行前后公交试验车辆道路运行工况与排放,进行数据统计分析。结果表明,限行措施使公交车辆平均车速提升了37.9%,怠速运行时间占比下降了6.28%,低于20 km/h的低速运行时间占比下降了15.5%,20~40km/h的中速运行时间占比增加了11.1%。限行使公交车辆平均加速度增大,平均比功率VSP变大。CO、HC和NOx的平均排放速率随车速、比功率VSP增大呈先增大后降低的趋势,随加速度增大而增大。限行使公交车辆负荷率增大,排气中CO、HC和NOx的平均排放速率较未限行时有所提高。相同运行里程下,限行使公交车辆运行时间减少27.5%。综合结果,限行使公交车辆尾气中CO、NOx和HC的排放量分别降低了21.71%、10.36%和11.95%,使平均排放因子降低。限行使道路拥堵情况得到改善,有效提高了公交车辆行驶速度,减少了尾气排放。

The article studies the effects of traffic control on the operating conditions and exhaust emission of the transit buses during the 2010 Asian Games Period in Guangzhou. The statistical analysis was preceded with the comparison of the test results of the on-road exhaust emission of the buses before and during the traffic restriction period via an on-board emission tests. The results show that during the traffic restriction period, the average speed of the buses was 11.1% higher as compared with the speed of no traffic restriction. At the same time, the rate of the idling running in terms of time length was 6.28 % lower than normal, and ratio of speed less than 20 km/h is 15.5% lower than usual. And, the ratio of the operating time between 20 and 40 km/h is 15.5% higher than usual. The average acceleration and the average VSP increase due to the traffic restriction. In addition, the average exhaust emission rate of CO, NOx and HC rose and then dropped with the increase of the speed and VSP of the buses, and increased with the traffic-running acceleration. Thus, on the whole, the traffic restriction made the bus load increase, and so did it make the average bus emission rate of CO, NO~ and HC higher than without traffic restriction period. Besides, the bus operating time turned to be 27.5 % lower than without restriction days for the same operating distance. Therefore, the general results tend to be the CO, NOx and HC emission mass of the transit buses cut short by 21.71% , 10.36% and 11.95 % as compared with that without traf- fic restriction period, respectively. In the meantime, the average e- mission factor of CO, NO~ and HC has been reduced. From what is said above, the traffic restriction measures can actually make the road congestion greatly relieved, with the running speed of bus faster, and with less pollutant emission.