在用国Ⅳ柴油公交车CCBC颗粒物排放特性
Characteristics of particulate matter emissions from an in-used China-Ⅳ diesel bus under CCBC

以1辆在用国Ⅳ柴油公交车为研究对象，在重型底盘测功机上进行中国典型城市公交循环(CCBC循环)排放试验，分析了该车CCBC循环的发动机工况特点，研究了PM0.1、PM0.1~2.5、PM2.5~10等3个粒径段的颗粒物数量和质量排放特性。研究结果表明：该国Ⅳ柴油公交车CCBC循环的发动机转速集中在600～1 338 r/min，转矩集中在0～400 N？m，说明该国Ⅳ柴油公交车CCBC循环的发动机工况以低速低转矩为主；该国Ⅳ柴油公交车CCBC循环PM0.1、PM0.1~2.5、PM2.5~10颗粒物数量排放因子分别为(1.21±0.07)×1013、(2.82±0.3)×1012、(1.66±0.07)×109个/km，可吸入颗粒物PM10数量排放中81.2%为粒径小于等于0.1μm的超细颗粒物PM0.1，且CCBC循环所有工况的PM0.1数量排放占PM10数量排放的比例超过70%；CCBC循环PM0.1、PM0.1~2.5、PM2.5~10颗粒物质量排放因子分别为（0.71±0.05）、（20.24±1.51）、（105.50±4.49） mg/km，可吸入颗粒物PM10质量排放中83.4%为粒径大于2.5 μm的细颗粒物PM2.5~10，且CCBC循环所有工况的PM0.1~2.5与PM2.5~10质量之和占PM10质量排放的约90%；CCBC循环中，车辆从怠速开始起步加速过程排放的超细颗粒PM0.1数量、质量占可吸入颗粒物PM10的数量及质量排放比例随着车速的上升而增大，数量比例最高达94.8%，质量比例最高达13.0%；车辆由加速过渡到匀速并进一步过渡到减速行驶时几乎不产生PM2.5~10颗粒质量排放；车辆减速时排放的可吸入颗粒物PM10数量、质量排放急速下降，颗粒物质量主要以PM2.5~10为主；CCBC循环车辆怠速、加速、匀速、减速4种行驶工况中，加速行驶工况产生的PM0.1、PM0.1~2.5、PM2.5~10颗粒数量、质量排放比例超过4种工况的颗粒物数量、质量排放总量的60%。
13An experimental study was conducted in an in-used China-Ⅳ diesel bus on heavy？？duty chassis dynamometer under CCBC (Chinese typical city bus driving cycle short for CCBC), laboratory driving cycle, and then the quantity and quality characteristics of PM0.1(particulate matter, d≤100 nm, d represents diameter), PM0.1~2.5 (particulate matter, 100 nm＜d≤2.5 μm), PM2.5~10(particulate matter, 2.5 μm＜d≤10 μm) emissions under CCBC were studied. The results show that the bus working condition under CCBC driving cycle is mainly located in 600~1 338 r/min for engine speed range and 0～400 N？m for torque range, which shows low speed and low torque are the main characteristics of the country. Particulate matter quantity emission factors of PM0.1, PM0.1~2.5 and PM2.5~10 under CCBC are respectively (1.21±0.07)×1013, (2.82±0.3)×1012, and (1.66±0.07)×109 per kilometer. 81.2% inhalable particulate matter quantity emission factor of PM10 is contributed to ultrafine particulate whose d≤0.1 μm. Besides, the quantity emission of PM0.1 in all working conditions accounts for over 70% that of PM10. Particulate matter quality emission factors of PM0.1,PM0.1~2.5 and PM2.5~10 under CCBC are respectively (0.71±0.05), (20.24±1.51), and (105.50±4.49) mg/km. 83.4% inhalable particulate matter quality emission factor of PM10 is contributed to fine particulate whose d>2.5 μm. Quality emissions of PM0.1~2.5 and PM2.5~10take about 90% proportion of quality emission of PM10 under all CCBC working conditions. Ultrafine particulate PM0.1 quantity and quality emission proportion increase with the increasing of vehicle speed during both the transition from idle to start and acceleration working condition. The maximum quantity proportion