Architecture Design and Analysis of Diesel Engine Exhaust Aftertreatment System and Comparative Study with Close-coupled DOC-DPF System 2008-01-1756

In response to the emissions standards for diesel engines, it is essential to have separate aftertreatment devices for controlling the specific tailpipe emissions like HC, CO, NO_x, and particulate matter. An advanced diesel exhaust aftertreatment system consists of channel-flow catalytic converters such as diesel oxidation catalyst (DOC), selective catalyst reduction (SCR) and wall-flow diesel particulate filters (DPF) each with discrete functions. Because of this multi-component aftertreatment system configuration, there are an increase in system complexity, development time and cost for doing experiments in order to evaluate various options and find the optimum aftertreatment system architecture.

The objective of this work is the development and application of an integrated aftertreatment system model including DOC, SCR, DPF and all connecting pipes. The study includes the baseline system performance, i.e. SCR forward system (DOC-SCR-DPF), DPF forward system (DOC-DPF-SCR), and DPF forward (DOC-DPF-SCR) aftertreatment system when DOC and DPF were closely coupled. Basically all component models were 1-D, quasi-steady with global kinetic approach. All component models are incorporated and integrated into a diesel exhaust aftertreatment simulation tool in Matlab/Simulink platform. The developed model was used for designing and analyzing different aftertreatment system architectures for a light-duty diesel engine. Both temperature and emissions reduction efficiency of each component were considered to improve the overall aftertreatment system performance to reduce tailpipe emissions.