基于远程监控三区移动平均窗口法的重型车排放特征

Heavy-duty vehicle emission characteristics based on the remote-monitoring three-bin moving-average window method

为了研究实际道路上重型车的排放特征,提出了一种基于远程监控数据的三区移动平均窗口(3B-MAW)模型,并与功基窗口法分析结果进行了对比。模型中远程监控无效数据主要包含NOx传感器未正常传输的数据和发动机停机后仍然上传的数据。每个数据点有可能落在1种、2种或3种区内,三区划分的比例与车辆的实际行驶工况有关。为了同时兼顾排放结果计算的准确性和所需数据量不过大,最小窗口数、窗口宽度、第1划分线和第2划分线这4个模型主要参数应分别设置在2400、300s,6%和20%附近。由于不受窗口功率阈值限制,相对于功基窗口法,3B-MAW模型能够实现对低负荷排放更为有效的核查,适合对实际道路随机工况进行分析。

A three-bin moving average window(3B-MAW)model was proposed and compared with the work-based window method(WB-WM)to investigate the on-road emission characteristics of heavy-duty vehicles.The invalid data of remote monitoring were mainly composed of the NOx sensor’s abnormal data and the uploaded data after the engine shutdown.In the 3B-MAW model,each data was attributed to one,two or three bins.The percentage of the three bins were linked to the vehicle’s real driving conditions.In order to gain the emission calculation accuracy and a smaller scale of required data,the value of the four main parameters,i.e.,the minimum window number,the window width,the first cut-off and the second cut-off are set around 2400 s,300 s,6%and 20%,respectively.Since the window power threshold is no longer required,the 3B-MAW method is able to capture the low load emission characteristics more effectively,compared to the WB-WM.Therefore,the 3B-MAW method is a more appreciate approach to analyse on-road random driving conditions.