Assessment of test cycle flexibilities, driving behavior, and their impacts on CO₂ results

The World-wide harmonized Light duty Test Procedure (WLTP) issued as UNECE GTR No. 15 has greatly reduced the flexibilities that are in the New European Driving Cycle (NEDC) procedure and has eliminated many loopholes. However a certain degree of flexibility in the test procedure is necessary, otherwise no type approval test would be valid. After-test corrections can therefore increase the repeatability of the test results and provide CO₂ values that better reflect the target cycle. The work presented in this paper shows the results of the practical implementation of some corrections, such as imbalances in the state of charge (SOC) of the battery; deviations against the target road load; target speed; target distance; and target soak temperature. In summary, all corrections steps performed in this study influenced the average CO₂ emissions by approximately 1.3% and 3.8%, for WLTP and NEDC respectively, which in our opinion is an indication of the reduction of flexibilities from NEDC to WLTP. For analyzing driving behavior during the NEDC and WLTC tests drive trace indices have been computed and reported. Some of them showed promising potential in detecting driving styles that can result in excessive or low fuel economy and subsequently higher or lower CO₂ emissions. Further tests and analyses are needed and warranted for a better understanding of this issue, setting the limits, and possible test corrections.

• Supplemental Notes:
  • This paper was sponsored by TRB committee ADC20 Standing Committee on Transportation and Air Quality.
• Corporate Authors:

  Transportation Research Board

  500 Fifth Street, NW
  Washington, DC  United States  20001
• Authors:
  • Pavlovic, Jelica
  • Ciuffo, Biagio
  • Fontaras, Georgios
  • Arcidiacono, Vincenzo
  • Anagnostopoulos, Konstantinos
  • Tsiakmakis, Stefanos
  • Valverde, Victor
• Conference:
  • Transportation Research Board 96th Annual Meeting
  • Location: Washington DC, United States
  • Date: 2017-1-8 to 2017-1-12
• Date: 2017

Language

• English

Media Info

• Media Type: Digital/other
• Monograph Title: TRB 96th Annual Meeting Compendium of Papers

Subject/Index Terms

• TRT Terms: Behavior; Carbon dioxide; Driving; Environmental impacts; Pollutants; Testing
• Subject Areas: Environment; Highways;

Filing Info

• Accession Number: 01628691
• Record Type: Publication
• Report/Paper Numbers: 17-04863
• Files: TRIS, TRB, ATRI
• Created Date: Mar 8 2017 5:09PM