The role of the driving dynamics beyond RDE limits and DPF regeneration events on pollutant emissions of a Euro 6d-temp passenger vehicle

Toumasatos, Zisimos; Raptopoulos-Chatzistefanou, A.; Kolokotronis, Dimitrios; Pistikopoulos, P.; Samaras, Zisis; Ntziachristos, Leónidas

doi:10.1016/j.jaerosci.2021.105947

Cited by 21 publications

(18 citation statements)

References 37 publications

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“…In general, two mechanisms of the regeneration event are responsible for the observed increase in NO x emissions, namely the increased engine-out levels and the reduced efficiency of the aftertreatment system. The first is related to the very low (if not zero) levels of EGR, as already shown in Figure 2 and reported in previous studies [27,32]. Closing the EGR valve allows a higher engine-out temperature and shifts the NO x /soot trade-off towards increased NO x formation and soot oxidation, favoured by the higher combustion temperatures and oxygen availability [42,43].…”

Section: Impact Of Dpf Regeneration On Emissions Of Individual Testssupporting

confidence: 56%

“…This is followed by a sharp increase in the second part, reflected in both instantaneous and cumulative values, where particles are oxidised and exhausted due to the lower filtration efficiency of the DPF. On top of that, PN emissions exhibit increased levels (compared to the case without DPF REG) for a short period after the regeneration, owing to the still inadequate soot cake [16,27]. Therefore, PN emissions cannot be considered a reliable indicator of the exact regeneration period but rather a flag that regeneration occurs due to their significant increase, which is relatively easy to identify [11].…”

Section: Using Tailpipe Temperature and Emissions Datamentioning

confidence: 99%

“…The availability of the relevant information depends on the test facilities (engine bench, chassis dynamometer, on-road testing) and measuring equipment (OBD scanner, laboratory emissions analysers, PEMS). As summarised in [27], the fuel injection strategy, EGR rate, boost pressure and throttling (either exhaust or intake) can indicate an active DPF regeneration. In some modern vehicles, there is also an OBD binary indicator that shows the occurrence of an active regeneration [21].…”

Section: Identification Of Active Dpf Regenerationmentioning

confidence: 99%

“…In addition, the required portable equipment for measuring sub-23 nm particles (both solid and total) on the road is still under development and optimisation [24][25][26]. A recent study employing such a novel exhaust gas sampling and dilution system revealed that the number of solid particles with a minimum size of 2.5 nm (SPN2.5) emitted during a DPF regeneration under steady-state conditions was 2.3 times higher than SPN23 [27]. Some data and information are also available on the total particle number (TPN) emissions (comprising non-volatile, semi-volatile and volatile components) during DPF regeneration [16,21,22,27,28].…”

Section: Introductionmentioning

confidence: 99%

“…A recent study employing such a novel exhaust gas sampling and dilution system revealed that the number of solid particles with a minimum size of 2.5 nm (SPN2.5) emitted during a DPF regeneration under steady-state conditions was 2.3 times higher than SPN23 [27]. Some data and information are also available on the total particle number (TPN) emissions (comprising non-volatile, semi-volatile and volatile components) during DPF regeneration [16,21,22,27,28]. In general, TPN increases orders of magnitude during a regeneration, raising concerns about whether these particles should be left unmonitored.…”

Section: Introductionmentioning

confidence: 99%

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Impact of Active Diesel Particulate Filter Regeneration on Carbon Dioxide, Nitrogen Oxides and Particle Number Emissions from Euro 5 and 6 Vehicles under Laboratory Testing and Real-World Driving

et al. 2022

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Particulate mass concentration is a crucial parameter for characterising air quality. The diesel particulate filter (DPF) is the primary technology used to limit vehicle particle emissions, but it needs periodic cleaning, a process called regeneration. This study aims to assess the impact of active DPF regeneration on the performance and emissions of Euro 5 and 6 vehicles. The study examined both carbon dioxide (CO2) and pollutant (nitrogen oxides (NOx) and particle number (PN)) emissions for eight vehicles tested in the laboratory and on the road. Apart from the DPF, a wide range of emission control systems was covered in this experimental campaign, including exhaust gas recirculation (EGR), diesel oxidation catalyst (DOC), lean NOx trap (LNT) and selective catalytic reduction (SCR) catalyst, revealing the different impacts on NOx emissions. The regeneration frequency and duration were also determined and used to calculate the Ki factor, which accounts for the emissions with and without regeneration, weighted over the distance driven between two consecutive regeneration events. Based on these outcomes, representative emission factors (EF) were proposed for the regeneration phase only and the complete regeneration interval. In addition, the effect of regeneration on efficiency was estimated and compared with other energy consumers. The results indicated a significant impact of DPF regeneration on CO2, NOx and PN emissions, higher in the case of driving cycle testing in the laboratory. The relevant mechanisms behind the elevated emission levels were analysed, focusing on the regeneration period and the test phase following immediately after. The calculation of the Ki factor and the comparison with the official values revealed some weaknesses in its application in real-world conditions; to overcome these, new NOx EF values were calculated, depending on the emission control system. It was revealed that Euro 6 vehicles equipped with SCR could comply with the applicable limits when considering the complete regeneration interval. Finally, it was indicated that the DPF regeneration impact on vehicle efficiency is similar to that of driving with the air conditioning (A/C) system and headlights on.

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