Non-repeatability of the WLTP vehicle test results

Authors

DOI:

https://doi.org/10.61089/aot2024.fjw8a575

Keywords:

WLTP, WLTC, exhaust emission, repeatability

Abstract

The paper presents results of considerations on the repeatability of the passenger car test results obtained in the WLTP procedure on a chassis dynamometer. The research concerned the aspects of exhaust emissions and fuel consumption. Measurements were carried out in the WLTC test with a cold engine start and then in four WLTC (Worldwide harmonized Light vehicles Test Cycle) tests with a hot engine start. The following values were measured: average specific distance emissions of hydrocarbons, non-methane hydrocarbons, carbon monoxide, nitrogen oxides, particulate matter and carbon dioxide, specific distance particulate number, and operational fuel consumption. Thus, it was possible to assess the impact of the engine's thermal state at start-up on the test results and the nature of test results repeatability with the start-up of a hot engine. The repeatability of the test results was assessed based on the coefficient of variation obtained in the individual tests and the relationship of the maximum difference between measurement results values in the individual tests for a hot engine start. The obtained test results turned out to be very diverse for the considered parameters and indicated low repeatability. Values of carbon dioxide emissions and operational fuel consumption were definitely the least varied in individual hot engine start tests. The exhaust emission of particulate matter varied the most in individual test iterations. However, the specific distance particulate number was relatively similar between individual tests, less so than the exhaust emission of other pollutants. In the case of different engine thermal state at start-up, the emitted particulate number varied the most in the test results, while the emission of carbon dioxide and operational fuel consumption varied the least. The repeatability of executing the velocity process in WLTC tests at hot engine and cold engine start-up was also examined as processes determining exhaust emissions and fuel consumption. These tests were much more repeatable than the exhaust emission and fuel consumption.

References

1. Aliramezani, M., Koch, Ch. R., Shahbakhti, M. (2022) Modeling, diagnostics, optimization, and control of internal combustion engines via modern machine learning techniques: A review and fu-ture directions. Progress in Energy and Combustion Science. 88, 100967. https://doi.org/10.1016/j.pecs.2021.100967.

2. Andrych-Zalewska, M., Chłopek, Z., Merkisz, J., Pielecha, J. (2019) Exhaust emission from a vehicle engine operating in dynamic states and conditions corresponding to real driving. Combus-tion Engines. 178(3), 99-105. https://doi.org/10.19206/CE-2019-317.

3. Andrych-Zalewska, M., Chłopek, Z., Merkisz, J., Pielecha, J. (2019) Determination of characteris-tics of pollutant emission from a vehicle engine under traffic conditions in the engine test. Combus-tion Engines. 191(4), 58-65. https://doi.org/10.19206/CE-147327.

4. Andrych-Zalewska, M., Chłopek, Z., Merkisz, J., Pielecha, J. (2021) Investigations of exhaust emissions from a combustion engine under simulated actual operating conditions in Real Driving Emissions Test. Energies. 14(4), 935. https://doi.org/10.3390/en14040935.

5. Andrych-Zalewska, M., Chłopek, Z., Merkisz, J., Pielecha J. (2021) Research on exhaust emissions in dynamic operating states of a combustion engine in a Real Driving Emissions test. Energies. 14(18), 5684. https://doi.org/10.3390/en14185684.

6. Andrych-Zalewska, M. (2023) Investigation of processes in the WLTC test of a passenger car with a diesel engine. Combustion Engines. 194(3), 52-62. https://doi.org/10.19206/CE-168328.

7. Chłopek, Z., Rostkowski, J. (2015). Non-repeatability of exhaust emission test results. Combustion Engines. 163(4), 92-100. ISSN 2300-9896.

8. Chłopek, Z., Szczepański, T. (2015) Rating causes the non-repeatability of an internal combustion engine operating states in the sets of his work conditions. Combustion Engines. 162(3), 708-711. ISSN 2300-9896.

9. DieselNet 2021. https://dieselnet.com/standards/cycles/iso8178.php.

10. Dorran, D. (2022) Digital Filters –A practical guide. https://doi.org/10.13140/RG.2.2.26017.48486.

11. Fayyazbakhsh, A., Bell, M. L., Zhu, X., et al. (2022) Engine emissions with air pollutants and greenhouse gases and their control technologies. Journal of Cleaner Production. 376, 134260. https://doi.org/10.1016/j.jclepro.2022.134260.

12. Gallagher, N. (2020) Savitzky-Golay smoothing and differentiation filter. Control System Engi-neering. https://doi.org/10.13140/RG.2.2.20339.50725.

13. Grigoratos, T., Gustafsson, M., Eriksson, O., Martini, G. (2018) Experimental investigation of tread wear and particle emission from tyres with different treadwear marking. Atmospheric Environment. 182, 200-212. https://doi.org/10.1016/j.atmosenv.2018.03.049.

14. Haleel, A. J., Hussein, R., Alkareem, F. A. (2018) Gage repeatability and reproducibility study. Association of Arab Universities Journal of Engineering Sciences Rosul. 25(1), 213-225. https://jaaru.org/index.php/auisseng/article/view/120/94

15. Hopwood, P., Shalders, B. (2020) Euro 7/VII – New emissions limits, the challenges and solutions. Ricardo. 30th April 2020 1500BST/1600CET. automotive.ricardo.com/euro7.

16. ISO 21748:2017. Guidance for the use of repeatability, reproducibility and trueness estimates in measurement uncertainty evaluation.

17. Jamrozik, A., Tutak, W., Grab-Rogaliński, K. (2021) Combustion stability, performance and emis-sion characteristics of a CI engine fueled with diesel/n-butanol blends. Energies. 14(10), 2817. https://doi.org/10.3390/en14102817.

18. Jaworski, A., Kuszewski, H., Ustrzycki, A., et al. (2018) Analysis of the repeatability of the ex-haust pollutants emission research results for cold and hot starts under controlled driving cycle conditions. Environmental Science and Pollution Research. 25(18), 17862-17877. https://doi.org/10.1007/s11356-018-1983-5.

19. Kha, M. Y., Shirish, A., Shimpi, S. A., Martin, W. T. (2015) The repeatability and reproducibility of particle number measurements from a heavy duty diesel engine. Emission Control Science and Technology. 1, 298-307. https://doi.org/10.1007/s40825-015-0026-7.

20. Kordos, P., Nieoczym, A. (2016) Analysis of unrepeatability of an SI engine based on measure-ments of indicated pressure. Applied Mechanics and Materials. 817, 3-12. https://doi.org/10.4028/www.scientific.net/AMM.817.3.

21. Mamarikas, S., Niziachristos, L., Fontaras, G., et al. (2019) Proceedings of the 23rd Transport and Air Pollution (TAP) conference – Part II. JCR Conference and Workshop Reports. 15th-17th May 2019, Thessaloniki, Greece. https://doi.org/10.2760/289885.

22. Maurya R. K. (2019) Combustion stability analysis. Reciprocating Engine Combustion Diagnos-tics. Mechanical Engineering Series. Springer, Cham. https://doi.org/10.1007/978-3-030-11954-6_8.

23. Reitz, R. D., Ogawa, H., Payri, R., et al. (2020) The future of the internal combustion engine. In-ternational Journal of Engine Research. https://doi.org/10.1177/1468087419877990.

24. Saylam, A. (2022) Methodology to reduce diesel engine pollutant emissions. International Journal of Petrochemistry & Natural Gas. 1(1), 4-8. https://www.opastpublishers.com/open-access-articles/methodology-to-reduce-diesel-engine-pollutant-emissions.pdf.

25. Schmid, M., Rath, D., Diebold, U. (2022) Why and how Savitzky-Golay filters should be replaced. ACS Measurement Science Au. 2(2), 185-196. https://doi.org/10.1021/acsmeasuresciau.1c00054.

26. Shenavarmasouleh, F., Arabnia, H. (2019) Causes of misleading statistics and research results irreproducibility: A concise review. 2019 International Conference on Computational Science and Computational Intelligence (CSCI), Las Vegas. 465-470. https://doi.org/10.1109/CSCI49370.2019.00090.

27. Shreekrushna, S. Y. (2019) Engine emissions and their control: Review. International Research Journal of Engineering and Technology (IRJET). 6(1), 450-456. https://www.irjet.net/archives/V6/i1/IRJET-V6I179.pdf

28. Worldwide Emission Standards. Passenger cars and light duty vehicles. Delphi. Innovation for the real world. 2020/2021.

29. Worldwide Emissions Standards 2022/2023. Passenger cars and light duty vehicles.

30. Ye, S., Lim, J. Y., Huang, W. (2022) Statistical considerations for repeatability and reproducibility of quantitative imaging biomarkers. BJR|Open. 4(1), 20210083. https://doi.org/10.1259/bjro.20210083.

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Published

2024-09-30

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Original articles

How to Cite

Merkisz, J., Sordyl, A., & Chłopek, Z. (2024). Non-repeatability of the WLTP vehicle test results. Archives of Transport, 71(3), 25-49. https://doi.org/10.61089/aot2024.fjw8a575

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