European regulation 2016/427 (the first package of the so-called Real-Driving Emissions (RDE) regulation) introduced on-road testing with Portable Emissions Measurement Systems (PEMS) to complement the chassis dynamometer laboratory (Type I) test for the type approval of light-duty vehicles in the European Union since September 2017. The Not-To-Exceed (NTE) limit for a pollutant is the Type I test limit multiplied by a conformity factor that includes a margin for the additional measurement uncertainty of PEMS relative to standard laboratory equipment. The variability of measured results related to RDE trip design, vehicle operating conditions, and data evaluation remain outside of the uncertainty margin. The margins have to be reviewed annually (recital 10 of regulation 2016/646). This paper lays out the framework used for the first review of the NO_x margin, which is also applicable to future margin reviews. Based on experimental data received from the stakeholders of the RDE technical working group in 2017, two NO_x margin scenarios of 0.24–0.43 were calculated, accounting for different assumptions of possible zero drift behaviour of the PEMS during the tests. The reduced uncertainty margin compared to the one foreseen for 2020 (0.5) reflects the technical improvement of PEMS over the past few years.

欧洲法规2016/427（所谓的“真实行驶排放”（RDE）法规的第一包）引入了带有便携式排放物测量系统（PEMS）的道路测试，以补充该类型的底盘测功机实验室（I型）测试自2017年9月起获得欧盟的轻型车辆批准。污染物的不超过（NTE）限值是I类测试限值乘以合格因子，该合格因子包括PEMS相对测量不确定性的余量到标准实验室设备。与RDE行程设计，车辆运行状况和数据评估相关的测量结果的可变性仍在不确定范围之内。利润率必须每年进行审查（第2016/646号法规第10条）。_x保证金，这也适用于将来的保证金审查。基于在2017年从RDE技术工作组利益相关者接收到的实验数据中，两个NO _X的计算0.24-0.43余量的场景，占在测试期间的PEMS的可能零点漂移行为不同的假设。与2020年的预期不确定性（0.5）相比，不确定性减少了，这反映了过去几年中PEMS的技术进步。