Development and review of Euro 5 passenger car emission factors based on experimental results over various driving cycles

Abstract

The emissions of CO2 and regulated pollutants (NOx, HC, CO, PM) of thirteen Euro 5 compliant passenger cars (seven gasoline, six Diesel) were measured on a chassis dynamometer. The vehicles were driven repeatedly over the European type-approval driving cycle (NEDC) and the more dynamic WMTC and CADC driving cycles. Distance-specific emission factors were derived for each pollutant and sub-cycle, and these were subsequently compared to the corresponding emission factors provided by the reference European models used for vehicle emission inventory compilation (COPERT and HBEFA) and put in context with the applicable European emission limits. The measured emissions stayed below the legal emission limits when the type-approval cycle (NEDC) was used. Over the more dynamic cycles (considered more representative of real-world driving) the emissions were consistently higher but in most cases remained below the type-approval limit. The high NOx emissions of Diesel vehicles under real-world driving conditions remain the main cause for environmental concern regarding the emission profile of Euro 5 passenger cars. Measured emissions of NOx exceeded the type-approval limits (up to 5 times in extreme cases) and presented significantly increased average values (0.35 g/km for urban driving and 0.56 g/km for motorway driving). The comparison with the reference models showed good correlation in all cases, a positive finding considering the importance of these tools in emission monitoring and policy-making processes.

Sooting propensities of some gasoline surrogate fuels: Combined effects of fuel blending and air vitiation

“…While diesel engines exhibit some relatively high performances, especially in terms of CO 2 specific emission (g/km) [4], they suffer from the acknowledged dilemma called NO…”

Nanoparticle Filtration Characteristics of Advanced Metal Foam Media for a Spark Ignition Direct Injection Engine in Steady Engine Operating Conditions and Vehicle Test Modes

“…Low cylinder temperature during engine start and first tip-in of the FTP-75 mode produces more wall-films, which result in significant particle emissions. Optimization of engine control strategy of multiple injections combined with high injection pressure during cold start and cold transient operation stage is most effective measures for reducing PN emissions [8][9][10][11][15][16][17][18]27,31,43]. Moreover, installation of the GFP in GDI engines is a straightforward pathway for reducing both the nucleation mode and the accumulation mode particles [36][37][38][39].…”

“…CARB has revealed that sub-23 nm particles comprise a substantial portion of the total PM emissions from GDI vehicles [5,9,21,29,30]. The primary reason for these controversial findings of differences between the particle measurement programme (PMP) methods and CARB relates to the sensitivity of the sampling and dilution approaches for the secondary particles formed from gaseous precursors [29][30][31][32].…”

“…Exhaust particles containing volatile organic compounds that are less than 23 nm in size formed during combustion in locally rich regions are substantially oxidized in the TWC, while almost all of the accumulation mode particles are passed through the catalyst without purification [25,27,[33][34][35]. Therefore, a cost-effective gasoline particulate filter (GPF) can be adopted for GDI vehicles to reduce the nano-PM emissions to satisfy future PN emission regulations [10,27,[29][30][31][36][37][38][39]. The physical characteristics of volume, space velocity, pressure drops, exhaust temperature for natural regeneration, and particle-filtering efficiency, including sub-23 nm particles that do not negatively affect vehicle exhaust emissions and fuel efficiency, should be considered for optimized performance [5,10,25,27,30,[36][37][38][39][40][41][42][43].…”

Embedding “roadside equipment” in the environmental assessment of transportation system: the case of safety barriers

“…Several analyses and methods were developed [23][24][25] to assess the vehicles' emissions as a function of their age, volume capacity, type of fuel, and mean velocity. Clearly, the application of these comprehensive methods requires the knowledge of detailed data concerning the fleets of running vehicles and their yearly change.…”