Gaseous and Particulate Exhaust Emissions of Hybrid and Conventional Cars over Legislative and Real Driving Cycles


Road transport exhaust emissions represent the main sources of atmospheric pollution in urban areas, due to the growing number of circulating vehicles and travelled distances. In order to reduce this pollution source, stricter emission standards are periodically set by governments through- out the world. Consequently, the concentrations of gaseous pollutants and particulate mass to be measured during type-approval tests of new vehicles are becoming progressively lower; moreover from 2011, diesel cars have to comply with particle number limit. In order to assess emission levels of different technology vehicles and investigate the use of a particulate number measurement technique at the exhaust of very low-emitting vehicles, an experimental activity was carried out on three in-use vehicles: a diesel car equipped with a particulate trap (DPF), a hybrid gasoline-elec- tric car and a bi-fuel passenger car fuelled with compressed natural gas (CNG). Cold and hot gaseous and particulate emission factors and fuel consumption were measured during the execution of real and regulatory driving cycles on a chassis dynamometer. Particulate was characterized in terms of mass only for the diesel car and of particle number for all vehicles. The emissions measured over the NEDC show that all three vehicles comply with their standard limits, except CO for CNG passenger car and NOx for diesel car. Cold start influences CO and HC emissions and fuel consumption for all the tested vehicles and in particular for the hybrid car. The real driving cycle is the most critical pattern for the emissions of almost all pollutants. During constant speed tests, the emissions of particles of hybrid car are an order of magnitude lower than those of the CNG car.

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Costagliola, M. , Prati, M. , Mariani, A. , Unich, A. and Morrone, B. (2015) Gaseous and Particulate Exhaust Emissions of Hybrid and Conventional Cars over Legislative and Real Driving Cycles. Energy and Power Engineering, 7, 181-192. doi: 10.4236/epe.2015.75018.

Conflicts of Interest

The authors declare no conflicts of interest.


[1] Gerlofs-Nijland, M.E., Campbell, A., Miller, M.R., David E Newby, D.E. and Cassee, F.R. (2009) Toxicity of Inhaled Traffic Related Particulate Matter. Journal of Physics, Conference Series, 151, 012049 (5pp).
[2] Loomis, D., Grosse, Y., Lauby-Secretan, B., El Ghissassi, F., Bouvard, V., Benbrahim-Tallaa, L., Guha, N., Baan, R., Mattock, H. and Straif, K. (2013) The Carcinogenicity of Outdoor Air Pollution. The Lancet Oncology, 14, 1262-1263.
[3] European Parliament and Council (2007) Regulation (EC) No 715/2007 of the European Parliament and of the Council of 20 June 2007 on Type Approval of Motor Vehicles with Respect to Emissions from Light Passenger and Commercial Vehicles (Euro 5 and Euro 6) and on Access to Vehicle Repair and Maintenance Information. Official Journal of the European Union L 171, pp. 1-16.
[4] UNECE Regulation No.83/Add.82/Rev.4 (2011) Agreement Concerning the Adoption of Uniform Technical Prescriptions for Wheeled Vehicles, Equipment and parts Which Can Be Fitted and/or Be Used on Wheeled Vehicles and the Conditions for Reciprocal Recognition of Approvals Granted on the Basis of These Prescriptions.
[5] Bergmann, M., Kirchner, U., Vogt, R. and Benter, T. (2009) On-Road and Laboratory Investigation of Low-Level PM Emissions of a Modern Diesel Particulate Filter Equipped Diesel Passenger Car. Atmospheric Environment, 43, 1908- 1916.
[6] Zarvalis, D., Tsakis, A., Konstandopoulos, A.G., Prati M.V. and Costagliola M.A. (2008) A Mobile Laboratory for On-Board and Ambient Level Emissions Measurement. SAE Vol. SP-2150 “Emissions Measurement & Testing, 2008” SAE Paper 2008-01-0756.
[7] Alvarez, R., Weilenmann, M. and Novak, P. (2008) Pollutant Emissions from Vehicles with Regenerating After-Treat- ment Systems in Regulatory and Real-World Driving Cycles. Science of the Total Environment, 398, 87-95.
[8] International Council on Clean Transportation—ICCT (2014) European Vehicle Market Statistics -Pocketbook 2014.
[9] Fontaras, G., Pistikopoulos, P. and Samaras, Z. (2008) Experimental Evaluation of Hybrid Vehicle Fuel Economy AND Pollutant Emissions over Real-World Simulation Driving Cycles. Atmospheric Environment, 42, 4023-4035.
[10] Zahabi, S.A.H., Miranda-Moreno, L., Barla, P. and Vincent, B. (2014) Fuel Economy of Hybrid-Electric versus Conventional Gasoline Vehicles in Real-World Conditions: A Case Study of Cold Cities in Quebec, Canada. Transportation Research Part D, 32, 184-192.
[11] Samaras, C. and Meisterling, K. (2008) Life Cycle Assessment of Greenhouse Gas Emissions from Plug-In Hybrid Vehicles: Implications for Policy. Environmental Science & Technology, 42, 3170-3176.
[12] Aslam, M.U., Masjuki, H.H., Kalam, M.A., Abdesselam, H., Mahlia, T.M.I. and Amalina, M.A. (2006) An Experimental Investigation of CNG as an Alternative Fuel for a Retrofitted Gasoline Vehicle. Fuel, 85, 717-724.
[13] Turrio-Baldassarri, L., Battistelli, C.L., Conti, L., Crebelli, R., De Berardis, B., Iamiceli, A.L., Gambino, M. and Iannaccone, S. (2006) Evaluation of Emission Toxicity of Urban Bus Engines: Compressed Natural Gas and Comparison with Liquid Fuels. Science of the Total Environment, 355, 64-77.
[14] Ristovski, Z., Morawska, L., Ayoko, G.A., Johnson, G., Gilbert, D. and Greenaway, C. (2004) Emissions from a Vehicle Fitted to Operate on Either Petrol or Compressed Natural Gas. Science of the Total Environment, 323, 179-194.
[15] Verbeek, H.A. (2004) Vehicle Exhaust Emission Measuring on Four Fuels. Proceedings of the International Conference on Vehicles Alternative Fuel Systems & Environmental Protection (VAFSEP), 6th-9th July 2004, Dublin City University, 86-91.
[16] Winkler, A., Dimopoulos, P., Hauert, R., Bach, C. and Aguirre, M. (2008) Catalytic Activity and Aging Phenomena of Three-Way Catalysts in a Compressed Natural Gas/Gasoline Powered Passenger Car. Applied Catalysis B: Environmental, 84, 162-169.
[17] Huai, T., Durbin, T.D., Rhee, S.H. and Norbeck, J.M. (2003) Investigation of Emission Rates of Ammonia, Nitrous Oxide and Other Exhaust Compounds from Alternative Fuel Vehicles Using a Chassis Dynamometer. International Journal of Automotive Technology, 4, 9-19.
[18] Andrè, M., Joumard, R., Vidona, R., Tassela, P. and Perret, P. (2006) Real-World European Driving Cycles, for Measuring Pollutant Emissions from High- and Low-Powered Cars. Atmospheric Environment, 40, 5944-5953.
[19] Tutuianu, M., Marotta, A., Steven, H., Ericsson, E., Haniu, T., Ichikawa, N. and Ishii, H. (2013) Tecnical Report on Development of a World-Wide Worldwide Harmonized Light Duty Driving Test Cycle (WLTC). UN/ECE/WP.29/ GRPE/WLTP-IG DHC Subgroup. Informal Document GRPE-68-03 (68th GRPE, 7-10 January 2014).
[20] Weiss, M., Bonnel, P., Hummel, R., Provenza, A. and Manfredi, U. (2011) On-Road Emissions of Light-Duty Vehicles in Europe. Environmental Science & Technology, 45, 8575-8581.
[21] Schreiber, D., Forss, A.M., Mohr, M. and Dimopoulos, P. (2007) Particle Characterisation of Modern CNG, Gasoline and Diesel Passenger Cars. SAE Technical Paper 2007-24-0123.
[22] Conger, M.B. and Holmén, B.A. (2012) Real-World Engine Cold Start and “Restart” Particle Number Emissions from a 2010 Hybrid and Comparable Conventional Vehicle. TRB 91st Annual Meeting, Washington DC, 22-26 January 2012, Paper #12-4570.
[23] Robinson, M. and Holmén, B.A. (2011) Onboard, Real-World Second-by-Second Particle Number Emissions from 2010 Hybrid and Comparable Conventional Vehicles. Transportation Research Record: Journal of the Transportation Research Board, 2233, 63-71.
[24] Holmen, B.A. and Ayala, A. (2002) Ultrafine PM Emissions from Natural Gas, Oxidation-Catalyst Diesel, and Particle-Trap Diesel Heavy-Duty Transit Buses. Environmental Science & Technology, 36, 5041-5050.
[25] Novosel, D. (2013) Best Practice for Controlling Content of Oil, Water and Sulphur in CNG at Refuelling Station Level. Svenskt Gastekniskt Center AB (SGC) Rapport 2013:291.
[26] del Álamo. J. (2013) NG/Biomethane Fuel Specification in Europe. CEN/TC 408.
[27] Maricq, M.M., Podsiadlik, D.H. and Chase, R.E. (1999) Gasoline Vehicle Particle Size Distributions: Comparison of Steady State, FTP, and US06 Measurements. Environmental Science & Technology, 33, 2007-2015.
[28] Mamakos, A., Dardiotis, C. and Martini, G. (2012) Assessment of Particle Number Limits for Petrol Vehicles. European Commission—Joint Research Centre—Institute for Energy and Transport, Report EUR 25592 EN.

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