Emission Analysis Through Numerical Simulation of Three-Way Catalytic Converter with Thermal Energy Storage

Abstract

One of the methods implied by the automakers to meet regulations upon automotive emissions is application of catalytic converter. The major challenge associated with the catalytic converter is its inactivity in conversion of emission until it reaches the light-off temperature. This work is intended to employ a technique to minimize the time taken by catalytic converter to attain light-off temperature and reduce its inactive period. The effect of thermal heat storage system on the operation of catalytic converter is analyzed using ANSYS CHEMKIN Pro software. Accordingly, emission analysis using numerical simulation of catalytic converter with Phase Change Material (PCM) is done to calculate the improvement in the performance of catalytic converter. Phase Change Material (Mg70Zn24.9Al5.1) with transition temperature of 613 K is formulated with catalytic converter, and simulation is done for three different loads (100%, 50%, and No load). During normal engine operation (charging period), PCM extracts some of the thermal energy from exhaust gas and stores in the form of sensible heat as well as latent heat. During engine off period, whatever heat is stored in PCM in the form of latent heat is transmitted back to substrate by undergoing partial or complete solidification to maintain substrate temperature in desired light-off temperature range for maximum conversion efficiency. The results from the simulation are substantiated experimentally. The results signify that application of PCM as a thermal energy storage leads to overall increment in the conversion efficiency during cold starting of the engine. This is evident from the continuous improvement of conversion of pollutants from exhaust gas in subsequent transient cycles.