Secondary Emissions

Abstract

Increasingly stringent emission standards, as well as the consideration of pollutants in future legislation, norms, and guidelines that remained unregulated so far, call for a continuous improvement of combustion and emission control systems. Besides harmful pollutants, climate-active substances have come into focus. E-fuels or fuels from biogenic sources have emerged during the last years with a wide range of chemical and physical properties and specific demands on combustion and aftertreatment. In this regard, the importance of secondary emissions is growing. For instance, secondary emissions can occur as a consequence of non-optimized engine and catalyst operation strategies or due to the disadvantageous design or operation conditions of catalytic converters. Within this study, a holistic literature research on the topic of secondary emissions was conducted with a particular focus on recent publications that became available within the last five years. The study was based on the FVV project 1278 “Secondary Emissions” from 2018. For this, research papers and final reports from FVV projects on the formation and abatement of secondary emissions, as well as legal texts and guidelines, were sifted. The resulting database was interpreted, evaluated, and converted into a usable tool in tabular format. Herein, technical aspects such as the impact of the fuel type, engine operation conditions, and catalyst technologies on the formation of secondary emissions are considered. In addition, information from the literature research on green-house potentials and risks for the health and environment of secondary emissions, as well as specific information on the relevant legislation and guidelines, are included in the tabular database. A final report sums up the state-of-the-art on secondary emissions and their abatement and will identify scientific-technical questions that remain unanswered so far.