G. Lonati

S. Casadei

T. Bellin

T. Rossi

English

Archivio istituzionale della ricerca - Politecnico di Milano

Laboratory and on-road tests assessment of fine and ultrafine particle emission factors for Euro 6LPG passenger cars Giovanni Lonatia, Tommaso Bellinb, Tommaso Rossib, Simone Casadeib a = Department of Civil and Environmental Engineering, Environmental section, Politecnico di Milano, Via Golgi 39, 20133 Milano, Italy; giovanni.lonati@polimi.itb = Innovhub - Stazioni Sperimentali per l’Industria, Fuels Department, Via G. Galilei 1, 20097 San Donato Milanese, Milano, Italy; tommaso.bellin@mi.camcom.it; simone.casadei@mi.camcom.it; tommaso.rossi@mi.camcom.itExhaust emissions of particulate matter for five Euro 6 bi-fuel (gasoline-LPG) passenger cars were measured during laboratory and on road tests. Small and medium segment cars from different manufacturers, both equipped with retrofit LPG powertrain and with original equipment manufacturer LPG powertrain, were selected in order to represent the Italian circulating fleet of Euro 6 bi-fuel passenger cars. Laboratory tests were carried out driving the cars on a chassis dynamometer according to different driving cycles. Regulatory particulate matter mass (PM) and solid particle number (PN-PMP compliant) were measured; additionally, soot was measured through a micro soot sensor, PN in the 0.007-10 μm and 5.6-560 nm range through an electrical low pressure impactor (PN-ELPI) and an engine exhaust particle sizer (PN-EEPS), respectively. On road tests were carried in and around the city of Milan in compliance with real drive emission (RDE) regulation, covering a distance of about 73 km. PN measurements were performed by a Portable Emissions Measurement System (PEMS) through a volatile particle remover followed by a diffusion charger detector. Emissions factors were separately calculated for gasoline and LPG fuelling and compared; related particle size distributions were analyzed. All the regulated emissions were compliant with the Euro 6 limits, except for PN of the only direct injection (DI) engine tested car with gasoline fuelling, which exceeded the limit both in laboratory and on road. In laboratory tests, very low PM emissions were measured for all the cars and for both the fuels, with no statistically significant variations between fuels. Conversely, LPG fuelling resulted in some significant reductions of PN-PMP compliant emissions for most cars over the different driving cycles; significant reductions with LPG fuelling were detected both for non-regulatory PN-ELPI and for PN-EEPS too. Soot emissions were very low with both fuels and generally lower with LPG but statistically significant only for the DI car. On road tests confirmed the results of bench tests, with an indicative reduction (up to 70%) of PN emission switching from gasoline to LPG fuelling.Keywords:LPG; Emission factors; Passenger cars; Laboratory tests; Real Driving Emissions 

Laboratory and on-road tests assessment of fine and ultrafine particle emission factors for EURO6 LPG passenger cars

Lonati, Giovanni

Bellin, Tommaso

Rossi, Tommaso

Casadei, Simone

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Ultrafine particles – Air quality and climateBrussels, Belgium 5th – 6th July, 2022BackgroundLaboratory and on-road tests assessment of fine and ultrafineparticle emission factors for Euro 6 LPG passenger carsGiovanni LONATI, Tommaso BELLIN, Tommaso ROSSI, Simone CASADEI Department of Civil and Environmental Engineering - Politecnico di Milanogiovanni.lonati@polimi.itInnovhub - Stazioni Sperimentali per l’Industria, Fuels Department A pool of five Euro 6 (B and C) LPG bi-fuel passenger cars was tested over several driving cycles (NEDC, ERMES, WLTC) and on road(RDE) on both gasoline and LPG fuelling. Switching from gasoline to LPG both in laboratory and on-road tests showed reduced particulate emissions and different size distributions,especially during the hot phases of the driving cycles PM and PN emission factors for LPG fuelling were calculated and made available at Italian and international level for updating EFsdatabases of emission models Liquefied petroleum gas (LPG)-gasoline bi-fuel passenger cars are a relevant share of the circulating fleet in some countries Italy has the second-largest circulating fleet (about 2.6 millions of vehicles) of LPG passenger cars in the European Union after Poland and the sixth-largestin the world Original equipment manufacturers (OEMs) bi-fuel vehicles, and conventional gasoline vehicles later retrofitted to operate with LPG accounted for 6.7% of theItalian passenger cars circulating fleet in 2020, 29.5% of these with Euro 6 homologation Updated emission factors (EFs) were not available for Euro 6 LPG passenger cars in the COPERT software, the standard vehicle emissions modeldeveloped for official road transport emission inventory compilation in EU member countries Italian country-specific EFs for Euro 6 passenger cars have been calculated based on data from both laboratory and on-road emission tests performed on apool of five Euro 6 LPG bi-fuel passenger cars representative of the different technologies of the circulating Italian fleetOn-road testsLaboratory testsMaterial and methodsResultsEmission factorsConclusionsCar 1 Car 2 Car 3 Car 4 Car 5EURO class Euro 6b Euro 6b Euro 6b Euro 6b Euro 6cType approval driving cycleNEDC NEDC NEDC NEDC WLTCEngine capacity [cm3]1248 1598 1197 1590 1598COPERT segment Small Medium Small Medium MediumInjection type PFI PFI DI PFI PFILPG powertrain Retrofit Retrofit Retrofit OEM OEMPFI = Port Fuel Injection; DI = Direct Injection Test carsNEDC +          ERMESTime (s)Speed (km/h)WLTCTime (s)Speed (km/h)Particle numberParticle massChassis dynamometer tests in a test cell (T = 23 ± 3 °C; RH = 50 ± 5 %) Tests with NEDC, WLTC, and ERMES (hot start) driving cycle3 NEDC, 3 ERMES, and 1 WLTC test for each fuel and each carMeasurements for regulated particle mass (PM) and solid particle number (PN-PMP compliant, 23 nm-2.5 μm range), and non-regulated particle number (PN-ELPI, 7 nm-10 μm range; PN-EEPS, 5.6-560 nm range) On-board system for PN (>23 nm) through a volatile particle remover followed by a diffusion charger detector 2 tests for each fuel and carUrban26 kmRural24 kmMotorway23 kmTest cars from different manufacturersSeparately tested with both commercial gasoline and LPGOn LPG tests car engines always started-up in gasoline mode, automatically switching to LPG after 1-2 minutesSize distributions (cars with statistically different PN-EEPS) Low PM emissions measured for all the tested cars and for both the fuels (0.005-0.426 mg/km range), well below the Euro 6NEDC limit (4.5 mg/km); no statistically significant variations detected between gasoline and LPG fuelling Euro 6 limit PN-PMP compliant respected only for LPG fuelling over the NEDC (only applied to Car 3): limit exceeded(+10.9%) over the NEDC (6.65E+11 #/km vs. 6.0E+11 #/km) and (+17.2%) over RDE (1.05E+12 #/km vs. 9.0E+11 #/km) forgasoline fuelling Generally lower emissions with LPG fuelling. Overall mean reductions (± mean st. dev.): 34.4% (±10.2%) for PN-PMPcompliant, 32.4% (±9.5%) for PN-ELPI, 17.8% (±9.1%) for PN-EEPS in laboratory tests; indicatively, up to around 70%reduction for PN in RDE tests LPG fuelling resulted in statistically significant reductions (Welch‘s t-test, α = 0.95) of PN-PMP compliant emissions only forCar 3 over NEDC (36.5%) and Car 1, 3, 4 over ERMES (36.2%, 85.6%, 89.8%); likewise, significant reductions alsoobserved for PN-ELPI and PN-EEPS Similar PN-EEPS size distributions over the whole NEDC, but marked difference over NEDC-EUDC and over ERMES in the10-100 nm range1,0E+101,0E+111,0E+121,0E+131,0E+10 1,0E+11 1,0E+12 1,0E+13LPG fuellingGasoline fuellingPN-PMP compliant emission factor (# km-1) NEDC ERMESWLTC RDE± 50% rangeEuro 6 limit NEDC (DI Cars)Euro 6 limit RDEDI Car 31,0E+101,0E+111,0E+121,0E+131,0E+10 1,0E+11 1,0E+12 1,0E+13LPG fuellingGasoline fuellingPN-ELPI emission factor (#7 nm-10 µm km-1) NEDCERMESWLTC± 50% range1,0E+101,0E+111,0E+121,0E+131,0E+141,0E+10 1,0E+11 1,0E+12 1,0E+13 1,0E+14LPG fuellingGasoline fuellingPN-EEPS emission factor (#5.6-560 nm km-1) NEDCERMESWLTC± 50% rangeAcknowledgments: The measurement campaign described in this work was supported by Assogasliquidi Federchimica1,0E+081,0E+091,0E+101,0E+111,0E+121,0E+131 10 100 1000dN/dlogDp [#/km]Dp [nm]Car 4 - PN-EEPS Size distribution over ERMESGasolineLPG1,0E+081,0E+091,0E+101,0E+111,0E+121,0E+131 10 100 1000dN/dlogDp [#/km]Dp [nm]Car 3 - PN-EEPS size distribution over NEDC-EUDCGasolineLPG1,0E+081,0E+091,0E+101,0E+111,0E+121,0E+131 10 100 1000dN/dlogDp [#/km]Dp [nm]Car 3 - PN-EEPS size distribution over NEDC-UDCGasolineLPG1,0E+081,0E+091,0E+101,0E+111,0E+121,0E+131 10 100 1000dN/dlogDp [#/km]Dp [nm]Car 3 - PN-EEPS size distribution over NEDCGasolineLPG

Laboratory and on-road tests assessment of fine and ultrafine particle emission factors for Euro 6 LPG passenger cars

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Laboratory and on-road tests assessment of fine and ultrafine particle emission factors for EURO6 LPG passenger cars

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