Update: Assessment of risks for elevated emissions of vehicles under the boundaties of RDE. Identifying relevant driving and vehicle conditions and possible abatement measures

With RDE (Real Driving Emissions) legislation a new chapter in emission testing has started for light-duty vehicles. RDE legislation poses new and more complex engineering targets for manufacturers. The expectation is that RDE will bring major improvements in the emission performance of LD vehicles for a large part of vehicle usage on European roads. However, a number of special, but not necessarily uncommon situations fall outside the boundaries for the test and vehicle conditions specified within the RDE legislation. It is important to ensure that the effectiveness of emission control strategies, or emission control systems, is guaranteed even in conditions that fall outside the scope of the RDE test conditions. Following the Heavy Duty regulation and also equivalent to the US legislation there is in RDE 2 the requirement introduced that the manufacturer will supply to the Granting Type-Approval Authority (GTAA) information on emission control strategies, i.e., the BES (Base Emission Strategy) and the AES (Auxiliary Emission Strategy). The Base Emission Strategy (BES) should be active inside but also outside the RDE boundaries unless there is an Auxiliary Emission Strategy (AES) approved by the granting type approval authority. This documentation is assessed by the GTAA based on the requirements in RDE 3 and on the guidance notice from the European Commission on the evaluation of Auxiliary Emission Strategies and the presence of Defeat Devices published on the 26 January 2017 (C(2017) 352 final).The GTAA may accept elevated emission in specific circumstances. Parts of this information are confidential and will not be available to third parties. The expected effect of an AES on pollutants and CO2-emissions needs to be reported by the manufacturer and is part of the evaluation by the GTAA. The magnitude of the increase of emissions is not tested and the occurrences of the AES in normal use, is not assessed. Therefore, rather than focussing on the declaration of an AES, as in RDE legislation, this report mainly focusses on circumstances and causes of elevated emissions, which may be observed in monitoring and independent testing, outside the premises of type approval. Only existing technologies to reduce emissions are considered.