Integrated Aftertreatment System Modeling Using GT-POWER
Syed Wahiduzzaman, Gamma Technologies Inc.
There has been great surge interest in modeling of aftertreatment systems in recent times due to legislative pressures to reduce vehicle emissions. While reduction of emissions at its source is being pursued, various promising technologies are emerging that are designed to curb emission at the exhaust system. In principle, modeling of such systems provides an efficient means to analyze system performance and examine relative effects of competing phenomena and even better interpret experimental data. One of challenges of aftertreatment modeling is that appropriate kinetics is a highly sensitive function of formulation and physical description of the catalysts. Often a set of global kinetics is used to model a particular catalyst and that are not generally valid for others. Furthermore, these mechanisms are closely guarded by the manufacturers and may not be readily shared. Additionally, the performance of catalysts also depends on the transient characteristics of the exhaust gas composition.
In order to address these issues, a Kinetics Library has been created in GT-POWER for modeling of aftertreatment kinetics. This library can be applied to model various aftertreatment devices incorporated as coupled subsystems of an overall engine/vehicle model. The Kinetics Library allows implementation of global and surface chemistry mechanisms without having to write user codes. The system integration allows transient input to catalyst system based on engine/vehicle performance. Furthermore, an arbitrary set of chemical mechanism can be incorporated into the catalyst model. Additionally, kinetics mechanism can even be encrypted if required. Examples of engine system model (detailed and mean value) integrated with diesel particulate filter (filtration and regeneration) and aftertreatment catalyst models will be demonstrated. It will be shown that complex aftertreatment systems can be modeled through arbitrary combinations of catalytic subsystems.