基于工况分布的重型环卫货车NO_x排放模型

NO_x Emission Model for Heavy-duty Refuse Trucks Based on Operating Modes

为提高城市重型环卫货车的NOx排放测算精度,本文提出一个基于工况分布的重型环卫货车NOx排放模型.首先,根据基于实测逐秒速度数据分析的环卫重型货车工况特征和NOx排放特性对不同负载货车的VSP区间进行划分;其次,结合货车瞬时速度建立不同负载的环卫重型货车运行模式区间划分方法,并对不同负载货车N Ox排放因子进行测算.结果显示,空载货车在速度区间[0, 20) km/h上,NOx排放因子大于满载,其他速度区间上相反.与基于MOVES模型测算结果对比,在不同速度区间上,基于MOVES的测算结果均比本文提出模型的测算结果偏低,如在低速区间[0,20) km/h,中速区间[20,50) km/h,高速区间[50,+∞) km/h:空载行驶时,分别低24.67%、6.82%和23.81%;满载行驶时,分别低12.38%、18.81%和26.43%.

In order to improve the accuracy of the NOx emission estimation for city heavy-duty refuse trucks, this paper presents an operating mode-based NOx emission model for heavy-duty refuse trucks. First, the VSP bins were defined based on the operating conditions and the emission characteristics of NOx derived from the analysis of second- by- second field speed data for fully loaded and empty heavy- duty refuse trucks respectively. Then, combined with the instantaneous speed of trucks, an operating mode binning method was developed and emission factors for trucks were estimated, which were subsequently compared with the results based on the MOVES model. It is shown that the emission factors of NOx are higher for empty loaded trucks at the low speed level of ([0, 20) km/h) than that of fully loaded trucks, and lower in other speed levels. However, emission factors of NOx estimated based on the MOVES model are lower on all speed levels for both fully and empty loaded trucks than those based on the NOx emission model proposed in this paper. For empty loaded trucks, the differences are found as much as 24.67%, 6.82% and 23.81% at the low speed level ([0,20) km/h), medium speed level ([20,50) km/h) and high speed level ([50,+∞) km/h) respectively. For fully loaded trucks, the differences are 12.38%, 18.81% and 26.43% respectively.