Reduction in Cold Start Emissions by Using PCM Based Catalytic Converter

Enhancing the Efficiency of Catalytic Converters for Reducing Cold Start Emissions

Abstract

Over the years air pollution has emerged as the biggest problem to the society. Governments are applying stringent norms for controlling these automotive emissions. There are many ways to reduce these emissions, out of which the use of catalytic converter appears to be the most efficient and reliable means of reducing automotive exhaust emissions. The problem with catalytic converter is that its efficiency is nearly zero during the engine starting and warm up period. As the temperature of catalytic converter increases, its conversion efficiency also increases. In the present work we tried to enhance the conversion efficiency of catalytic converter by using heat bath for storing latent heat in it. Phase change material (PCM) is used as a media for latent heat storage in heat bath. Under normal engine operating conditions, PCM will absorb the heat of exhaust gas and it will change its phase from solid to liquid. During discharging period i.e. engine off period, PCM will undergo partial solidification thereby giving its stored latent heat to the catalytic converter. This will help the converter to remain hot for maximum conversion efficiency which will help in reducing cold start emission for next cold start period. From the results it is clear that cold start emissions have decreased to a large extent at all compression ratios and loads.