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

Abstract

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.

Emission ratio determination from road vehicles using a range of remote emission sensing techniques

“…Diesel oxidation catalysts (DOC) are used to deliberately oxidise exhaust gas components such as CO and hydrocarbons to less harmful products, but also oxidise NO to NO 2 . Optimising the ratio of NO to NO 2 using an oxidation catalyst supports the performance of SCR systems and promotes passive regeneration of diesel particulate both of which are positioned downstream of the DOC (Schaefer et al, 2009;Lowell and Kamakaté, 2012;Dimaratos et al, 2022).…”

Effect of speed humps on instantaneous traffic emissions in a microscopic model with limited deceleration capacity

“…The continuous increase of vehicles on the road leads to the emission of motor vehicle pollutants becoming one of the main sources of air pollution in major and medium-sized cities, which poses a great threat to human health and the ecological environment. [1][2][3][4][5] It is well-known that the power of a vehicle comes from the fuel combustion within the engine; this process is not perfect. Therefore, exhaust gas is inevitably discharged.…”

“…The exhaust emissions of road vehicles account for more than half of the total PM emissions in urban areas, and in some metropolises in developed countries, the proportion even exceeds 80%. [5][6][7] CO 2 is also one of the main gases that cause global warming; automobile exhaust emissions account for about 17% of HC and 23% of CO 2 emissions, anthropogenic carbon emissions behaviors have accelerated the process of global warming and seriously threaten the sustainable development of human society and ecosystems. [8][9][10][11] In addition, a large amount of NO X produced by automobile exhaust emissions forms ozone (O 3 ) after chemical reaction with VOC, which is an important factor causing regional composite pollution.…”

The Influence of the Type and Condition of Road Surfaces on the Exhaust Emissions and Fuel Consumption in the Transport of Timber

“…The authors of the work [17] attempted to determine the relation between real-world traffic and the emission of nitrogen oxides, carbon dioxide, PM number, and DPF active regeneration performed in laboratory tests. The investigations performed on eight Euro 5 and Euro 6 vehicles showed a significant influence of the DPF regeneration on the level of exhaust emissions of the above-mentioned exhaust components, confirming, inter alia, the elevated emission of CO 2 .…”