Ultra-low NOx diesel aftertreatment: An assessment by simulation

Abstract

Upcoming Euro 7/VII regulations are under discussion, and, from available information, they will focus not only on reducing the current emission limits but also on all those operating conditions that are still responsible for high emission events (e. g. cold start or altitude) as well as regulating secondary emissions with a major focus on GHGs (N2O, CH4 and HCHO). In this perspective, robustness towards a broader range of operative and environmental conditions and high conversion efficiency against all pollutants species will be demanded to aftertreatment systems.In an engine development process, the activity of aftertreatment architecture selection requires huge efforts in terms of time, hardware procurement, facilities and resources. That is because different topological layouts, different technologies and different interactions between the engine and the After-Treament System (ATS) must be investigated to find the most suitable solution. In this perspective, virtual testing is a strong and precious tool to accelerate and substantially reduce development effort with respect to an experimental campaign.The present work aims at showing a deep dive into an aftertreatment modeling and simulation approach in which experimental data coming from steady state and dynamic characterizations are used at first to calibrate 1D catalyst kinetic models and in a second step as input to homologation cycles for ATS performance evaluations. Modeling, validation and an example of aftertreatment technology and layout screening in the context of Euro 7 future scenario proposed by CLOVE will be discussed as well, to clarify how a technology emission reduction walk could be built with such an approach.