Abstract
Vehicle emission certification is evaluated under laboratorial conditions, where vehicles perform a standard driving cycle in controlled conditions leading to several critics, which have resulted in the implementation of the Worldwide harmonized Light Vehicle Test Procedure (WLTP) and the Real Driving Emissions (RDE) testing procedure, as a complementary certification procedure. RDE is still under debate since boundary conditions; evaluation and trip selection methods are still being studied to allow test reproducibility. Currently, the official data analysis method uses the moving average window (MAW_EC), based on the WLTP CO2 emissions for trip validity evaluation (RDE package 4) and emissions (RDE package 3). However, this does not consider the impact of vehicle dynamics. Consequently, this work focuses on developing a novel method to relate certification driving cycle dynamics and on-road test vehicle dynamics, to evaluate RDE tests fuel use and exhaust emissions in a comparable way to certification driving cycles, indicating how close, or far, real-world driving is from the laboratorial certification test. For this, a new method was developed called road vehicle evaluation method (ROVET), which relies on the cycle vehicle dynamic and on-road trip dynamics for assessing if both tests are comparable. Results from 5 measured vehicles with a portable emissions measurement system (PEMS) through reproducibility tests and 2 case studies, show that the ROVET provides results closer to the certification calculated reference than the most commonly used method in Europe (1% avg. difference for ROVET while 8% avg. difference for MAW_EC, regarding CO2 emission, for example). The use of vehicle dynamics on construction and references of a method could be used to incentivize the regulators to review the references used by the current used methods, which suffers several criticisms since their release. As the regulated methods are in constant update, this study could be useful for helping to improve or to be used as additional method for future vehicle certification procedures.
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Abbreviations
- a:
-
Acceleration [m/s2]
- CI:
-
Compression ignition
- CO:
-
Carbon monoxide
- CO2 :
-
Carbon dioxide
- DOC:
-
Diesel oxidation catalytic converter
- DPF:
-
Diesel particulate filter
- EC:
-
European Commission
- EPA:
-
United States Environmental Protection Agency
- FTP-75:
-
EPA Federal Test Procedure
- GPS:
-
Global Positioning System
- Grade:
-
Road slope
- HC:
-
Hydrocarbons
- HDV:
-
Heavy-duty vehicles
- ICE:
-
Internal combustion engine
- ISC:
-
In-service conformity
- IST-PEMS:
-
Instituto Superior Técnico Portable Emission Measurement System
- JRC:
-
Joint Research Center
- LDV:
-
Light-duty vehicle
- MAW_EC:
-
Moving average window
- MOVES:
-
Motor vehicle emissions simulator
- MPFI:
-
Multi point fuel injection
- NEDC:
-
New European Driving Cycle
- NO:
-
Nitrogen oxide
- NO2 :
-
Nitrogen dioxide
- NOx :
-
Nitrogen oxides
- O2 :
-
Oxygen
- PB:
-
Power binning
- PEMS:
-
Portable emissions measurement system
- RDE:
-
Real driving emissions
- ROVET:
-
Road vehicle evaluation method
- SI:
-
Spark ignition
- SPF:
-
Specific standardized power frequency
- TWC:
-
Three-way catalytic converter
- UNECE:
-
United Nations Economic Commission for Europe
- v:
-
Speed [m/s]
- VSE:
-
Vehicle specific energy
- VSP:
-
Vehicle specific power
- WLTC:
-
Worldwide Harmonized Light Vehicle Test Cycle
- WLTP:
-
Worldwide Harmonized Light Vehicle Test Procedure
References
Alves J, Baptista PC, Gonçalves GA, Duarte GO (2016) Indirect methodologies to estimate energy use in vehicles: application to battery electric vehicles. Energy Convers Manag 124:116–129. https://doi.org/10.1016/j.enconman.2016.07.014
Degraeuwe B, Thunis P, Clappier A, Weiss M, Lefebvre W, Janssen S, Vranckx S (2016) Impact of passenger car NOx emissions and NO2 fractions on urban NO2 pollution - scenario analysis for the city of Antwerp, Belgium. Atmos Environ 126:218–224. https://doi.org/10.1016/j.atmosenv.2015.11.042
Demuynck J, Bosteels D, De Paepe M, Favre C, May J, Verhelst S (2012) Recommendations for the new WLTP cycle based on an analysis of vehicle emission measurements on NEDC and CADC. Energy Policy 49:234–242. https://doi.org/10.1016/j.enpol.2012.05.081
Duarte GN de O (2013) A methodology to estimate vehicle fuel consumption and pollutant emissions in real-world driving based on certification data
Duarte GO, Varella RA, Gonçalves GA, Farias TL (2014) Effect of battery state of charge on fuel use and pollutant emissions of a full hybrid electric light duty vehicle. J Power Sources 246:377–386. https://doi.org/10.1016/j.jpowsour.2013.07.103
Duarte GO, Gonçalves GA, Baptista PC, Farias TL (2015) Establishing bonds between vehicle certification data and real-world vehicle fuel consumption - a vehicle specific power approach. Energy Convers Manag 92:251–265. https://doi.org/10.1016/j.enconman.2014.12.042
Duarte GO, Gonçalves GA, Farias TL (2016) Analysis of fuel consumption and pollutant emissions of regulated and alternative driving cycles based on real-world measurements. Transp Res Part D Transp Environ 44:43–54. https://doi.org/10.1016/j.trd.2016.02.009
European Commission (2016) Commission regulation (EU) 2016/427 of 10 march 2016 amending regulation (EC) no 692/2008 as regards emissions from light passenger and commercial vahicles (Euro 6). Off J Eur Union
Faria MV, Varella RA, Duarte GO, Farias TL, Baptista PC (2018) Science of the total environment engine cold start analysis using naturalistic driving data: city level impacts on local pollutants emissions and energy consumption. Sci Total Environ 630:544–559. https://doi.org/10.1016/j.scitotenv.2018.02.232
Fontaras G, Zacharof NG, Ciuffo B (2017) Fuel consumption and CO2 emissions from passenger cars in Europe – laboratory versus real-world emissions. Prog Energy Combust Sci 60:97–131. https://doi.org/10.1016/j.pecs.2016.12.004
Franco V, Zacharopoulou T, Hammer J, Schmidt H, Mock P, Weiss M, Samaras Z (2016) Evaluation of exhaust emissions from three diesel-hybrid cars and simulation of after-treatment Systems for Ultralow Real-World NOx emissions. Environ Sci Technol 50:13151–13159. https://doi.org/10.1021/acs.est.6b03585
Frey HC, Rouphail NM, Unal A, Colyar JD, Carolina N (2001) Measurement of on-road tailpipe CO, NO , and hydrocarbon emissions using a portable instrument
Frey H, Unal A, Chen J, Li S, Xuan C (2002) Methodology for developing modal emission rates for EPA’s multi-scale motor vehicle & equipment emission system. State Univ. US EPA, Ann Arbor, MI, pp 18–20
Gallus J, Kirchner U, Vogt R, Benter T (2017) Impact of driving style and road grade on gaseous exhaust emissions of passenger vehicles measured by a portable emission measurement system (PEMS). Transp. Res. Part D Transp. Environ 52:215–226. https://doi.org/10.1016/j.trd.2017.03.011
Giechaskiel B, Clairotte M (2017) Real driving emissions: 2017 assessment of PEMS measurement uncertainty
Haq G, Weiss M (2016) CO2 labelling of passenger cars in Europe: status, challenges, and future prospects. Energy Policy 95:324–335. https://doi.org/10.1016/j.enpol.2016.04.043
Hausberger S (2016) “CLEAR user guide for version 2 . 0,” no. July, pp. 1–14
Hausberger S, Lipp S (2017) Evaluation methods for real drive emission tests of LDV for a future legislation emissions in real driving situations demands for PEMS-tests at LDV 1–11
Hooftman N (2018) A review of the European passenger car regulations – real driving emissions vs local air quality. Renew Sust Energ Rev 86:1–21. https://doi.org/10.1016/j.rser.2018.01.012
Hu J, Frey HC (2017) Comparison of real world light-duty gasoline vehicle emissions for high altitude mountainous versus low altitude Piedmont study areas
Jimenez-Palacios J (1998) Understanding and quantifying motor vehicle emissions with vehicle specific power and TILDAS remote sensing
Khan T, Frey HC (2016) Evaluation of light duty gasoline vehicle rated fuel economy based on in- use measurements 7908:21–29. https://doi.org/10.3141/2570-03
Ligterink NE (2017) On-road determination of a reference CO2 emission for passenger cars
Marta A, Faria DV (2016) Evaluating the impacts of driver performance and driving environment on fuel consumption, emissions and safety
O’Driscoll R, ApSimon HM, Oxley T, Molden N, Stettler MEJ, Thiyagarajah A (2016) A portable emissions measurement system (PEMS) study of NOx and primary NO2 emissions from Euro 6 diesel passenger cars and comparison with COPERT emission factors. Atmos Environ 145:81–91. https://doi.org/10.1016/j.atmosenv.2016.09.021
Pavlovic J, Ciuffo B, Fontaras G, Valverde V, Marotta A (2018) How much difference in type-approval CO2emissions from passenger cars in Europe can be expected from changing to the new test procedure (NEDC vs. WLTP)? Transp Res Part A Policy Pract 111:136–147. https://doi.org/10.1016/j.tra.2018.02.002
Portuguese Assosciation of Automotive Producers (ACAP) (2018)“Statistics From The Automotive Sector, 2018 (Estatísticas do Sector Automóvel: Edição 2018)”
Samaras Z (2015) Update on the European PEMS activities for the assessment of real driving emissions (RDE). PEMS 2015 Int. Conf. Work. UC Riverside, USA
Stewart A, Hope-Morley A, Mock P, Tietge U (2015) Quantifying the impact of real-world driving on total CO2 emissions from UK cars and vans: final report for the committee on climate change, pp 1–52
Suarez-Bertoa R, Mendoza-Villafuerte P, Bonnel P, Lilova V, Hill L, Perujo A, Astorga C (2016) On-road measurement of NH3 and N2O emissions from a Euro V heavy-duty vehicle. Atmos Environ 139:167–175. https://doi.org/10.1016/j.atmosenv.2016.04.035
Thiel C, Nijs W, Simoes S, Schmidt J, van Zyl A, Schmid E (2016) The impact of the EU car CO2 regulation on the energy system and the role of electro-mobility to achieve transport decarbonisation. Energy Policy 96:153–166. https://doi.org/10.1016/j.enpol.2016.05.043
Tietge U, Mock P, German J, Icct AB, Tno NL (2017) From laboratory to road a 2017 update of official and “ real-world ” CARS IN EUROPE
Triantafyllopoulos G, Katsaounis D, Karamitros D, Ntziachristos L, Samaras Z (2018) Experimental assessment of the potential to decrease diesel NOxemissions beyond minimum requirements for Euro 6 real drive emissions (RDE) compliance. Sci Total Environ 618:1400–1407. https://doi.org/10.1016/j.scitotenv.2017.09.274
UNECE (United Nations Economic Commission for Europe) (2010) Addendum 82: regulation no. 83 revision 4 - uniform provisions concerning the approval of vehicles with regard to the emission of pollutants according to engine fuel requirements
Varella RA (2016) Cold-running NOx emissions comparison between conventional and hybrid powertrain configurations using real world driving data. SAE Tech Pap. https://doi.org/10.4271/2016-01-1010.Copyright
Varella RA, Villafuerte PM (2017) Comparison of data analysis methods for European real driving emissions regulation, p 6. https://doi.org/10.4271/2017-01-0997.Copyright
Varella RA, Duarte G, Baptista P, Mendoza Villafuerte P, Sousa L (2017) Analysis of the influence of outdoor temperature in vehicle cold-start operation following EU real driving emission test procedure. SAE Int J Commer Veh 10:596–697. https://doi.org/10.4271/2017-24-0140
Varella RA, Faria MV, Baptista PC, Mendoza-villafuerte P, Sousa LA, Duarte GO (2018) On -road tests and real driving e missions for light-duty vehicles :
Vlachos TG, Bonnel P, Weiss M, Giechaskiel B, Riccobono F (2015a) New Euro 6 Legislation on RDE : Overview and Technical Challenges
Vlachos TG, Bonnel P, Weiss M, Giechaskiel B, Riccobono F (2015b) Evaluating the real-driving emissions of light-duty vehicles : a challenge for the European emissions legislation
Vlachos T, Pierre B, Weiss M, Giechaskiel B, Riccobono F, Mendoza-Villafuerte P, Perujo A (2016) The Euro 6 real - driving emissions ( RDE ) procedure for light - duty vehicles : effectiveness and practical aspects Der Euro 6 RDE Abgastest für Kraftfahrzeuge : Wirksamkeit und praktische Anwendung abstract 1 introduction. In: 37th Int. Vienna Mot. Symp, pp 1–20
Weiss M, Bonnel P, Hummel R, Manfredi U, Colombo R, Lanappe G, Le Lijour P, Sculati M (2011) Analyzing on-road emissions of light-duty vehicles with portable emission measurement systems ( PEMS ). https://doi.org/10.2788/23820
Weiss M, Bonnel P, Kühlwein J, Provenza A, Lambrecht U, Alessandrini S, Carriero M, Colombo R, Forni F, Lanappe G, Le Lijour P, Manfredi U, Montigny F, Sculati M (2012a) Will Euro 6 reduce the NO x emissions of new diesel cars? - insights from on-road tests with portable emissions measurement systems (PEMS). Atmos Environ 62:657–665. https://doi.org/10.1016/j.atmosenv.2012.08.056
Weiss M, Bonnel P, Kühlwein J, Provenza A, Lambrecht U, Alessandrini S, Carriero M, Colombo R, Forni F, Lanappe G, Le Lijour P, Manfredi U, Montigny F, Sculati M (2012b) Will Euro 6 reduce the NO x emissions of new diesel cars? - insights from on-road tests with portable emissions measurement systems (PEMS). Atmos Environ 62:657–665. https://doi.org/10.1016/j.atmosenv.2012.08.056
Acknowledgments
Acknowledgments are to the National Council of Scientific and Technological Development (CNPq–Brazil) for the Doctoral financial support of Roberto Aliandro Varella (202097/2014-5). Patrícia C. Baptista acknowledges Fundação para a Ciência e Tecnologia for financing her contract (CEECIND/02589/2017).
Funding
This study is funded by the Fundação para a Ciência e Tecnologia for IN+ Strategic Project UID/EEA/50009/2013 and project UID/EMS/00712/2013. This study is funded by the Fundação para a Ciência e Tecnologia for IN+ Strategic Project UID/EEA 50009/2019 and IDMEC, under LAETA, project UID/EMS/00712/2019.
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Research highlights
• Presents a novel data analysis method for evaluating on-road emissions data
• The developed method establishes a connection between the RDE tested vehicle and the laboratorial certification procedure.
• Use of vehicle dynamics as fundamental parameter, mainly vehicle specific energy
• The developed method provides results closer to the certification than the most commonly used method (1% avg. difference for ROVET while 8% avg. difference for MAW_EC, regarding CO2 emission)
Appendices
Annex 1. Emissions sensitivity analysis
Emissions sensitivity was tested for CO2 and NOx distance specific emissions (see Fig. 12), since they constitute the main emissions researched at transportation area (Degraeuwe et al. 2016; Fontaras et al. 2017; Franco et al. 2016; Haq and Weiss 2016; Ligterink 2017; O’Driscoll et al. 2016; Stewart et al. 2015; Triantafyllopoulos et al. 2018). Speed variation, specifically when multiplied by 4 and 2, influences the results, mostly because CO2 emissions are influenced by the larger number of windows, hence increasing the emissions. A small number of windows (v/2 and v/4) do not change the result considerably (1%), providing a stable behavior. The VSP influence is also reduced, and the combination of speed and VSP behavior is mostly influenced by the speed. In addition, the speed and VSP criteria chosen lead to good results in terms of difference from certification. Both are near the respective certifications, presenting an average deviation of 0.5% for vehicle no. 1 and 0.25% for vehicle no. 2.
The same procedure was performed for NOx distance specific emissions, as presented in Fig. 13. Again, the influence of speed is observed, particularly when the filter is larger, presenting an average deviation of 19% for vehicle no. 1 and 2% for vehicle no. 2.
It is important to underline that, since vehicle no. 1 is a CI vehicle and vehicle no. 2 is a SI vehicle, the NOx emission magnitude is different between propulsion technologies.
Annex 2. Emissions sensitivity analysis
ROVET vs MAW_EC vs certification regarding CO2
Figure 14 provides a comparison between ROVET, MAW_EC method, and certification values (these values were estimated for the total cycle and its phases), for both vehicle nos.1 and 2 and for the two trips. MAW_EC results are presented for the total trip performed and driving category (urban, rural, and motorway). Thus, for comparing the certification and ROVET analysis from the phases of the WLTC, the logic applied to calculating the reference points of the MAW_EC was used, which considers the CO2 value of the WLTC for the phase 1, phase 3, and phase 4. Thus, urban, rural, and motorway results are compared to the phases 1, 3, and 4 of the ROVET analysis and certification calculated value.
ROVET vs MAW vs certification regarding NOx
Figure 15 presents the results of the comparison between the ROVET, MAW_EC and certification for both vehicle nos. 1 and 2 and for the two trips performed, regarding NOx. ROVET results are closer or under the certification reference than the MAW_EC in 10% average for the ROVET against 31% to the MAW_EC. This may be an effect of the use of dynamic data as reference, instead of CO2 emission as reference, which is a consequence of the dynamic parameters, such as speed, acceleration, and road grade. It is important to state that NOx emissions on SI vehicle tend to have lower magnitudes than CI, which can give a scale effect on the presentation of results. It is also interesting to note that for the total and phases analysis, both methods behave similarly, indicating that both follow a good correlation within each other.
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Varella, R.A., Ribau, J.P., Baptista, P.C. et al. Novel approach for connecting real driving emissions to the European vehicle laboratorial certification test procedure. Environ Sci Pollut Res 26, 35163–35182 (2019). https://doi.org/10.1007/s11356-019-06484-1
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DOI: https://doi.org/10.1007/s11356-019-06484-1