Longevity of Diesel Particulate Filters in Heavy-Duty Vehicles
Time: Tue 2026-03-10 10.00
Location: Kollegiesalen, Brinellvägen 8, Stockholm
Video link: https://kth-se.zoom.us/j/67570329235
Language: English
Subject area: Chemical Engineering
Doctoral student: Samuel af Ugglas , Processteknologi
Opponent: Professor Petr Kočí, University of Chemistry and Technology, Tjeckien
Supervisor: Universitetslektor Henrik Kusar, Processteknologi; Professor emeritus Lars Pettersson, Processteknologi; Doktor Anders Ersson, TRATON AB
QC 20260211
Abstract
The diesel particulate filter (DPF) is a critical component for the abatement of the harmful pollutant particulate matter (PM) from diesel engines. Accumulation of PM in DPFs increases flow restrictions, resulting in elevated backpressure for the exhaust gases. To mitigate the increase in backpressure, a regeneration process is applied, by which the soot is removed by oxidation. To enhance the regeneration process the DPF can be coated with a catalyst. The ash originating from the engine oil, remains in the DPF and will eventually determine its lifespan. PM composition is not static, catalysts age, and ash varies in properties and distributions, all affecting the performance of DPFs. This thesis investigates the different aspects concerning DPF performance and durability. Soot oxidation, catalyst deactivation, low-temperature regeneration, and ash accumulation have been investigated and discussed regarding its role for the continuous and prolonged use of DPFs. To capture practical relevance, field-retrieved DPFs have been studied and compared to fresh and non-catalyzed DPFs, whereby the experiments have been conducted at different scales, in both laboratory and real engine environments. Soot from different sources was shown to have a low variation in reactivity and was therefore not considered to be a critical parameter for DPF functionality. Instead, DPFs collected from the field revealed a significant decrease in NO conversion capability as a result of catalyst poisoning. The lower NO conversion created unfavorable conditions for the low-temperature regeneration. Well-controlled regeneration was shown to be important for the control of the ash distribution pattern. However, the results showed that ash packing density had a stronger influence on the backpressure than the distribution pattern. The research provides a deeper understanding concerning the aging and performance of DPFs, which can enable extended use, reuse, and remanufacturing of DPFs.