重型柴油车污染物排放因子测量的影响因素

为了调查我国重型柴油车排放污染物的基本水平,确定CO、HC、NO_x和颗粒物等污染物的排放因子,利用满足国Ⅲ排放标准的重型柴油车,分别采用PEMS(portable emission measurement system,车载排放测试系统,由便携式SEMTECH-DS型气态污染物排放测量设备和DMM颗粒物排放测量设备组成)及满足法规排放测量要求的重型车整车底盘测功机方法,研究了不同负载(0%、50%、100%及120%)和2种测试工况对重型车排放因子测量的影响. 结果表明:过载(120%负载)下NO_x和颗粒物等排放因子均比零负载下高出近90%；在平均车速较低、怠速时间长的VECC工况下,气态污染物、颗粒物的排放因子比平均车速高、怠速时间短的C-WTVC工况高出30%左右；PEMS系统和重型车底盘测功机系统所测气态污染物排放因子的相关性较好,但DMM颗粒物排放测试设备与重型车整车底盘测功机所测的颗粒物排放因子相差可达50%左右. 

Study of Parameters Influencing Measurement on Heavy Duty Diesel Vehicle's Emission Factors

In order to investigate the emission levels of heavy duty diesel vehicles in China and to determine emission factors for CO, HC, NO_x, PM, and other pollutants, heavy duty diesel vehicles meeting the China Stage Ⅲ emission standard were investigated under different loads (0%, 50%, 100% and 120%) and two running cycles with a great difference on the driving characteristics. Both Portable Emissions Measurement System (SEMTECH-DS equipment for gaseous pollutants and DMM instrument for PM measurement) testing and complete heavy-duty vehicle chassis dynamometer testing (as required in the emissions regulations) were conducted in this study. The results showed that vehicle loads significantly effected on the vehicle emission factor measurements. Emission factors of NO_x, PM tested under 120% load could be nearly 90% higher than that when tested under 0% load. The emission factors tested with the driving cycle of the low average speed and long idle time could be about 30% higher than that when tested with a high average speed and short idle time driving cycle. Gaseous pollutant emissions measurements showed a significant correlation between the SEMTECH equipment and the CVS system on the chassis dynamometer. However, the variation of PM results were more than 50% between the DMM instrument and the CVS system on the chassis dynamometer.