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It is commonly accepted that future powertrains will be based to a large extent on hybrid architectures, in order to optimize fuel efficiency and reduce CO₂ emissions. Hybrid operation is typically achieved with frequent engine start-and-stops during real-world as well as during the legislated driving cycles. The cooling of the exhaust system during engine stop may pose problems if the substrate temperature drops below the light-off temperature. Therefore, the design and thermal management of after-treatment systems for hybrid applications should consider the 3-dimensional heat transfer problem carefully. On the other hand, the after-treatment system calculation in the concept design phase is closely linked with engine calibration, taking into account the hybridization strategy. Therefore, there is a strong need to couple engine simulation with 3d aftertreatment predictions.

Hydrocarbon traps for gasoline engines are promising candidates for cold start emission control, provided that their design is based on a “systems approach”. In this paper, an existing CAE methodology for exhaust after-treatment is expanded to include HC trap technology. The flow, heat transfer and chemical kinetics in a typical complex system, comprising a “barrel type” adsorber and two conventional catalysts are studied. A mathematical model is developed and applied for the computation of the flow and pressure distribution, as well as transient heat transfer in the barrel type adsorber. A physically relevant model is used to simulate HC adsorption desorption on the adsorbing material. The model is used in combination with an existing 2-d 3-way catalyst model to simulate different HC trap concepts. The aim is to understand and quantify the particular thermal response and HC retention behavior of hydrocarbon adsorber systems.