Mechanical Engineering Department-Instituto Superior Técnico (IST), Universidade de Lisboa, Av. Rovisco Pais, Pav. De Mecânica III, Subsolo 2.10, 1, 1049-001, Lisbon, Portugal.
AVL MTC Motortestcenter AB, Armaturvägen 1, 13623, Haninge, Sweden.
Environ Sci Pollut Res Int. 2019 Dec;26(34):35163-35182. doi: 10.1007/s11356-019-06484-1. Epub 2019 Nov 4.
Vehicle emission certification is evaluated under laboratorial conditions, where vehicles perform a standard driving cycle in controlled conditions leading to several critics, which have resulted in the implementation of the Worldwide harmonized Light Vehicle Test Procedure (WLTP) and the Real Driving Emissions (RDE) testing procedure, as a complementary certification procedure. RDE is still under debate since boundary conditions; evaluation and trip selection methods are still being studied to allow test reproducibility. Currently, the official data analysis method uses the moving average window (MAW_EC), based on the WLTP CO emissions for trip validity evaluation (RDE package 4) and emissions (RDE package 3). However, this does not consider the impact of vehicle dynamics. Consequently, this work focuses on developing a novel method to relate certification driving cycle dynamics and on-road test vehicle dynamics, to evaluate RDE tests fuel use and exhaust emissions in a comparable way to certification driving cycles, indicating how close, or far, real-world driving is from the laboratorial certification test. For this, a new method was developed called road vehicle evaluation method (ROVET), which relies on the cycle vehicle dynamic and on-road trip dynamics for assessing if both tests are comparable. Results from 5 measured vehicles with a portable emissions measurement system (PEMS) through reproducibility tests and 2 case studies, show that the ROVET provides results closer to the certification calculated reference than the most commonly used method in Europe (1% avg. difference for ROVET while 8% avg. difference for MAW_EC, regarding CO emission, for example). The use of vehicle dynamics on construction and references of a method could be used to incentivize the regulators to review the references used by the current used methods, which suffers several criticisms since their release. As the regulated methods are in constant update, this study could be useful for helping to improve or to be used as additional method for future vehicle certification procedures. Graphical abstract.
车辆排放认证是在实验室条件下进行评估的，车辆在受控条件下执行标准驾驶循环，这导致了一些批评，从而实施了全球统一轻型车辆测试程序 (WLTP) 和实际驾驶排放 (RDE) 测试程序，作为补充认证程序。RDE 仍在争论中，因为边界条件、评估和行程选择方法仍在研究中，以允许测试重现性。目前，官方数据分析方法使用移动平均窗口 (MAW_EC)，基于 WLTP CO 排放进行行程有效性评估 (RDE 包 4) 和排放 (RDE 包 3)。然而，这并没有考虑车辆动态的影响。因此，这项工作的重点是开发一种新的方法来将认证驾驶循环动态与道路上的测试车辆动态相关联，以便以与认证驾驶循环可比的方式评估 RDE 测试的燃料使用和废气排放，并指示实际驾驶与实验室认证测试的接近程度或差异程度。为此，开发了一种称为道路车辆评估方法 (ROVET) 的新方法，该方法依赖于循环车辆动力学和道路行驶行程动力学来评估这两种测试是否具有可比性。通过可重复性测试和 2 个案例研究，对 5 辆装有便携式排放测量系统 (PEMS) 的测量车辆进行的结果表明，ROVET 提供的结果比欧洲最常用的方法 (例如，对于 CO 排放，ROVET 为 1%，MAW_EC 为 8%) 更接近认证计算参考值。在构建和引用方法时使用车辆动力学可以促使监管机构审查当前使用方法所使用的参考值，自发布以来，这些参考值受到了多次批评。由于受监管的方法在不断更新，因此本研究可能有助于改进或作为未来车辆认证程序的附加方法加以利用。
