国Ⅲ柴油公交车尾气排放实际道路测试研究

On-Road Emission Characteristics of "China Ⅲ" Emission Standard Diesel Bus

应用车载式尾气排放测试设备对北京国Ⅲ排放标准的柴油公交车在实际道路上的尾气排放特征进行了实测研究,测试时间为10 552 s,行驶里程达到61.97 km,共获得10 552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。车辆在实际道路上尾气排放NOx、CO、THC和PM的排放因子分别为14.12±2.54g/km、8.04±2.51 g/km、0.158±0.022 g/km和3.16±1.73 g/km。研究结果表明,油耗及污染物排放与各行驶工况下的速度、加速度均密切相关,车辆在高速加速行驶状态下易产生高的排放速率。车速小于10 km/h时排放因子远大于车速较快时的排放因子,车辆在加速时的排放因子最大,减速时最小。车辆在30 km/h～50 km/h速度区间内等速行驶时,油耗与排放因子最为经济且环境友好。测试车辆排放的颗粒形态主要集中在累积模式,属于纳米或超细微粒。

Two typical in-use diesel buses which meets ＂China Ⅲ＂ emission standard were selected to do on-road emission tests with the use of portable emission measurement system in Beijing.The distance of testing was 61.97 km,the time of testing was 10 552s,and 10 552 groups of bus data were obtained.The running cycle in the testing can reflect the real on-road running cycle.The emission factors of the tested bus are 14.12±2.54g/km,8.04±2.51 g/km,0.158±0.022 g/km and 3.16±1.73 g/km for NOx,CO,THC and PM respectively.This study illustrates that the diesel bus emission is strongly related to speed and acceleration driving cycles.The emission rates of all pollutants are high when speed is lower than 10 km/h;higher pollutant emission rates were tested during the high speed and acceleration zone in the driving cycle map.The fuel consumption and emissions during the steady speed of 30~50 km/h were much lower than the other driving patterns.The particulate matters which mainly belong to nano-particles or ultrafine particles were focused on accumulation mode.