State of the Art Accelerated Aging Methodology and Correlation with Vehicle-Aged Components 2022-01-0564

To fulfill stringent emission legislation requirements, it is essential to understand the relation between aging processes of the exhaust gas aftertreatment system (ATS) and its performance. The Stage V compliant heavy-duty non-road aftertreatment system, which was used in this study, is comprised of a diesel oxidation catalyst (DOC) placed directly after the engine, followed by a particulate filter with a selective catalytic reduction (SCR) active coating (SCRoF) and is completed by an SCR-coated substrate combined with an NH₃ oxidation catalyst. Each of the ATS components has to work in synergy and interact with each other to fulfill the emission legislation requirements. During vehicle operation, the ATS is exposed to various chemical and physical factors, which deteriorate its performance over its lifetime.

In this work, the accelerated aging methodology is presented. In this methodology, the aging processes, which happen during real-world-operation, were reproduced in a controllable step-by-step way on an engine test bench. The aging steps include: low and high temperature exposure, sulfur poisoning, hydrocarbons (HC) poisoning and exothermic HC burn-off, inducement of urea deposits formation, soot and ash loading. Each aging step was followed by a detailed ATS performance assessment. As a result of the so-performed aging, a full-useful-life (FUL) ATS was obtained and as a proof-of-concept it was successfully compared to a vehicle-aged ATS from the fleet. The effectiveness of the proposed accelerated aging methodology was also confirmed by an in-depth chemical and structural investigations of both aged aftertreatment systems.