A study on the CO2 and NOx emissions performance of Euro 6 diesel vehicles under various chassis dynamometer and on-road conditions including latest regulatory provisions

Georgios Triantafyllopoulos; Athanasios Dimaratos; Leonidas Ntziachristos; Yoann Bernard; Jan Dornoff; Zissis Samaras

doi:10.1016/j.scitotenv.2019.02.144

A study on the CO₂ and NO_x emissions performance of Euro 6 diesel vehicles under various chassis dynamometer and on-road conditions including latest regulatory provisions

Sci Total Environ. 2019 May 20:666:337-346. doi: 10.1016/j.scitotenv.2019.02.144. Epub 2019 Feb 11.

Authors

Georgios Triantafyllopoulos¹, Athanasios Dimaratos¹, Leonidas Ntziachristos², Yoann Bernard³, Jan Dornoff³, Zissis Samaras¹

Affiliations

¹ Mechanical Engineering Department, Aristotle University of Thessaloniki, Greece.
² Mechanical Engineering Department, Aristotle University of Thessaloniki, Greece. Electronic address: leon@auth.gr.
³ International Council on Clean Transportation, Berlin, Germany.

PMID: 30798242
DOI: 10.1016/j.scitotenv.2019.02.144

Abstract

The current study presents a detailed analysis of the gaseous emissions, focusing on CO₂ and NO_x, of diesel vehicles under several operating conditions. An assessment is also made on the impact and effectiveness of the Real Driving Emissions (RDE) test, which is mandatory by the European Union (EU) type approval regulation for passenger cars since September 2017. The method followed comprises emissions measurement tests on three Euro 6 diesel vehicles, under laboratory and various on-road operation conditions. Chassis dynamometer tests in the laboratory showed that emissions over the current type approval test (World-wide harmonized Light-duty Test Procedure or WLTP), and over the former one (New European Driving Cycle or NEDC), poorly reflect real-world levels. However, the most demanding CADC testing comes closer to real drive emissions. Comparison of driving conditions on the chassis dynamometer over different driving cycles and on the road reveals that the emission performance substantially varies between different tests, even for apparently similar operation conditions. The NO_x emissions reduction strategy of pre-RDE monitoring Euro 6 vehicles seems to be optimized for the NEDC driving conditions, which are not representative of the real-world driving conditions. The real-world emissions during normal driving conditions are effectively captured with the new RDE test, however driving the vehicle dynamically, at conditions outside the RDE regulation boundaries, results to disproportional high emissions. This is a significant shortcoming which might be critical for populations living on hilly areas or those close to specific micro-environments, such as highway entrance ramps, traffic lights, etc.

Keywords: CO(2); Driving style; NO(x); RDE; Road grade; WLTP.