Earlier this week, member states in the European Commission’s Technical Committee - Motor Vehicles (TCMV) gave support to the EC proposal for Real Driving Emissions (RDE) testing requirements.
The goal of RDE, which began its development in January 2011 and is targeted for implementation in the upcoming EU6c Emission Regulation in 2017, is to add emissions measurement under real-world driving as an additional type approval requirement. The goal is more closely to match certified output of tailpipe pollutants such as NOx and particulate matter to real world use; research has shown that real-world emissions—particularly that of NOx from diesels—have been far exceeding regulatory levels. (e.g., Earlier post.)
The RDE legislation will require engines to be clean under all operating conditions; this will impose significant challenges on the design and the calibration of engines.
Broadly, the approved RDE proposal includes:
The use of portable emission measurement systems (PEMS) and not-to-exceed (NTE) regulatory concepts.
A two-phase implementation. During a first transitional period the test procedures should only be applied for monitoring purposes, while afterwards they should be applied together with binding quantitative RDE requirements to all new type approvals/new vehicles. The final quantitative RDE requirements are to be introduced in two subsequent steps.
In establishing the quantitative RDE requirements, statistical and technical uncertainties of the measurement procedures are to be taken into account. (As AVL notes, driving a vehicle on the road will never be 100% reproducible. The influence of the road profile, the ambient conditions, the traffic situation as well as the behavior of the driver itself significantly influence the results. One-to-one comparison of test results will not be possible; instead it is necessary to handle and evaluate the test data using statistical methods.)
An individual RDE test at the initial type approval cannot cover the full range of relevant traffic and ambient conditions. Therefore in-service-conformity testing must ensure that the widest possible range of such conditions is covered by a regulatory RDE test, thereby providing for compliance with the regulatory requirements under all normal conditions of use.
Small volume manufacturers may receive exemptions.
RDE test procedure should be updated and improved if necessary to reflect, e.g., changes in vehicle technology. To assist the revision procedure, vehicle and emissions data obtained during the transitional period should be considered.
The European Automobile Manufacturers’ Association (ACEA) called the RDE regulation proposal as it currently stands “very incomplete”, as what was agreed was just a partial set of evaluation conditions for real driving emissions.
ACEA calls on the Commission to urgently deliver a complete proposal for Real Driving Emissions by June or July at the latest for a positive decision in the regulatory committee. We need to make more progress on clarifying all testing conditions to ensure a robust RDE regulation could commence from September 2017. Automobile manufacturers remain concerned about the piecemeal approach the Commission is taking in preparing this proposal. This is not smart regulation. We need clarity in advance so that we can plan the development and design of vehicles in line with the new requirements.—Erik Jonnaert, Secretary General of ACEA