Effect of Flow Distribution on Emissions Performance of Catalytic Converters

Distribution characteristics of exhaust gases and soot particles in a wall-flow ceramics filter

“…A uniformity index of 1.0 represents a completely uniform flow, while a value of 0.0 corresponds to a completely concentrated flow. The usual range of g is between 0.7 and 0.98 (Martin et al, 1998), but an index lower than 0.8 is hardly acceptable for an automobile catalytic converter. The exhaust mass flow rate of a diesel engine varies significantly with engine operation, and results in a wide range of operating conditions.…”

Modeling of Catalytic Exhaust Aftertreatment Systems: From Laboratory Reactor Data to Successful Prediction of Emissions From Vehicles

“…Some earlier papers describe the modelling fundamentals of the modern honeycomb three-way-catalyst [3], while more recent research is focused on the development of kinetic models of modern aftertreatment systems, like NO xstorage catalysts [4]. Not to forget from an engineering perspective are models associated with the heat transfer in pipes [5], or flow simulations and their effect on emission performance [6], as well as models developed for specific purposes, such as on-board diagnostics (OBD) [7].…”

Understanding Flow through Catalytic Converters

“…Flow uniformity was increased by utilizing higher cell density monoliths with smaller hydraulic diameter and by splitting the monolith into two parts separated by a gap [8][9][10][11]. Lower flow uniformity was observed in 3D steady state and transient numerical simulations in systems with higher monolith-to-inlet diameter ratios [12,13]. In particular, the design of the inlet diffuser was found to play an important role in the converter design [14,15].…”