在用柴油车排放劣化特性评价方法研究

Research on Evaluation Method of Emission Deterioration Characteristics of In-use Diesel Vehicles

车辆排放劣化状况与车辆有效寿命期内零部件的磨损和老化等因素有关,也受到车辆使用条件、维护保养状况影响,因此,在车辆正常使用过程中,基于实际道路驾驶排放(real driving emission,RDE)试验方法测试车辆更能真实反映车辆排放状况.文中研究跟踪测试一辆配置柴油机氧化催化器(Diesel Oxidize Catalyst,DOC)和选择还原系统(Selective Catalyst Reduction,SCR)的国五N2柴油车进行车辆排放劣化特性研究.排放测量采用车载排放测试设备(Portable Emission Measure System,PEMS),排放数据处理分别采用柴油车单位行驶里程排放因子和基于功基窗口法的单位功率排放因子处理方法.试验结果表明:所测试的N2车辆排放随着车辆行驶里程的增加而出现劣化现象;基于最小二乘法拟合获得的有效寿命期终点的CO、NOx排放满足RDE法规要求;计算得到的N2柴油车CO、NOx排放劣化系数均大于HJ438-2008标准的推荐值.有必要对柴油车排放耐久性进行实际道路试验研究.

The deterioration of vehicle emissions is related to factors such as the wear and aging of vehicle components during the vehicle’s useful life,and is also affected by the conditions of use and maintenance of the vehicle.Therefore,testing the vehicle based on the real driving emission(RDE)test method during the normal use of the vehicle can more truly reflect the vehicle emission status.In this study,a China-V N2 diesel vehicle equipped with DOC and SCR system is tracked and tested to study the deterioration characteristics of vehicle emissions.The emission measurement adopts the Portable Emission Measure System(PEMS),and the emission data processing adopts the diesel vehicle emission factor per mileage and the emission factor per unit of power based on the work-based window method.The test results show that the measured N2 vehicle emissions deteriorate with the increase in vehicle mileage.The CO and NOx emissions at the end of the vehicle’s useful life obtained based on the least squares fitting meet the requirements of RDE regulations.The calculated CO and NOx emission deterioration factors of N2 diesel vehicles are greater than the recommended values in HJ 438-2008 standard.It is necessary to conduct real road emission tests on diesel vehicle emission durability.