Potential for Euro 6 Passenger Cars with SCR to Meet RDE Requirements

Authors

Dr.-Ing. B. Holderbaum, Dipl.-Ing. M. Kind,
Dr.-Ing. C. Menne, Dipl.-Ing. (FH) T. Wittka,
FEV GmbH, Aachen; G. Vagnoni M.Sc., FEV Italia S.r.l., Rivoli; D. Bosteels M.Sc., MBA, C. Favre,
J. May B.Sc., M.Sc., CChem, Association for Emissions Control by Catalyst (AECC), Brussels

Year

2015

Print Info

Fortschritt-Berichte VDI, Reihe 12, Nr. 783

Summary

The RDE (Real Driving Emissions) legislation will require highly efficient DeNOX systems in the complete operating range of the vehicle. Selective Catalytic Reduction (SCR) technology has proven its performance already in numerous passenger cars which are compliant with the current Euro 6 legislation. In the presented study, AECC and FEV investigated the RDE compliance potential of SCR-based solutions in on-road driving tests with Portable Emission Measurement System (PEMS) and demonstrated the specific challenges in comparison with NEDC and WLTC emissions tests on the chassis dynamometer. The E-segment test vehicle with SCR-coated DPF (SDPF) was in the first step investigated with the available emission calibration, which was targeting Euro 6b emission limits. In the RDE test, the reduced EGR rate in higher engine load regions caused a significantly elevated level of NOx raw emissions. Even though the NOX conversion of the SDPF system was at the same time higher than 85 %, the NOx tailpipe emissions exceeded a conformity factor of 3. This characterizes the starting point of the calibration work using the existing aftertreatment system on the test vehicle. With dedicated recalibration of both the EGR and the urea dosing strategy, a significant reduction of the NOx raw and tailpipe emissions was reached, so that in the finally conducted RDE-route NOx conformity factors between 1.1 and 1.6 have been achieved.