Abstract
The present work aims to analyse and compare the energy performances of active and passive emission control systems. To this purpose, a one-dimensional unsteady model has been developed. The model has permitted to evaluate the heat exchange between the solid and the exhaust gas and to estimate energy effectiveness of the systems. Furthermore, the effect of the engine operating conditions on the performances of aftertreatment systems has been investigated considering standard emission test cycles. The analysis has shown that the active flow mode presents the greatest thermal inertia. As a consequence, the reversed flow control appears more suitable to maintain the converter initial temperature level for a longer time after variations in engine load. Conversely, the traditional passive flow control is preferable when rapid “cooling” or “heating” of the solid phase is requested.
Keywords: Aftertreatment systems, active and passive flow control, numerical analysis, energy efficiency, emission test cycles.