城市公交车在实际道路上的CO_2排放特征

On-road CO_2 Emission Characteristics of City Bus

应用车载式尾气排放测试设备对北京国Ⅲ、国Ⅳ排放标准的柴油公交车和国Ⅲ排放标准压缩天然气公交车在实际道路上的尾气CO2排放特征进行了实测研究,测试时间为30 787 s,行驶里程达到168.58 km,共获得30 787组有效数据,测试数据能够反映车辆在实际道路上的排放特征。3种类型车辆测试期间在实际道路上的CO2排放因子分别为(1.10±0.24)g/m、(0.99±0.23)g/m和(1.02±0.21)g/m。车辆的排放状况与车辆的行驶工况有密切关系,车速较低,加速度越大,CO2排放速率和排放因子越大,车辆在匀速且车速较快时排放速率和排放因子较低。

Seven typical in-use buses which include two diesel buses meetingChina Ⅲ emission standard, two diesel buses meeting China Ⅳ emission standard, and three CNG buses meeting China Ⅲ emission standard were selected to do on-road CO2 emission tests with the use of portable emission measurement system in Beijing. The road distance of testing was 168.58 kin, the time of testing was 30 787 s, and data groups were obtained for 30 787 of the bus. The running cycle in the testing can typically reflect the real on-road running cycle. The emission factors of the three types of bus are （1.10± 0.24） g/m, （0.99±0.23） g/m and （1.02±0.21） g/m respectively. The study illustrated that CO2 emission is strongly related with its speed and acceleration driving cycles. Higher emission rates were tested during the low speed and acceleration zone in the driving cycle map. Lower emission were tested during the high speed and constant speed zone.