Abstract
In recent years several efforts have been dedicated to cope with the new emission standards severe conditions and to improve the thermal management of the catalyst. Electrically heated catalysts and external burner-like systems are among the different solutions that have been investigated in the literature. The present research work provides an accurate description of a simulation framework developed to thoroughly investigate such applications. Modeling efforts have been dedicated to deeply characterize the multi-physics phenomena that affect a typical after-treatment system: some details are provided about how the characterization of the catalyst microstructure is achieved, how the transient storage phenomena of different chemical species can be taken into account, as well as how the radiative heat transfer, extremely significant for the electrically heated catalyst application, is evaluated. The numerical methodology is applied to a simplified exhaust line in combination with engine-out data from Real Driving Emission (RDE) test conditions for a three-cylinder turbocharged gasoline engine. The study simulates a burner-like system and an electrically heated catalyst, monitoring a conventional three-way catalyst. The advanced modeling framework allows to investigate the effects of the peculiar features of each specific catalyst heat-up technology. Both the heating devices are effective in inducing an early catalyst light-off, resulting in improved abatement efficiencies. However, they differ in their impact on flow and temperature distribution at the catalyst entrance, with electrical heating offering advantages due to its more uniform temperature across the section, particularly near the canning, leading to improved conversion efficiency.
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