EXPERIMENTAL INVESTIGATION OF COLD START EMISSIONS USING ELECTRICALLY HEATED CATALYSTS IN A SPARK IGNITION ENGINE

The population of spark-ignition vehicles in urban areas is very high and is increasing rapidly due to their convenience for short distance transportation. These vehicles are major sources of urban air pollution compared to vehicles with diesel engines. Catalytic converters are used to control their emissions but they attain their maximum conversion rates of about 80%-90% under optimum operating conditions and are not effective during cold start conditions. The objective of the present work is to demonstrate that an electrically heated catalyst (EHC) in combination with a traditional converter can achieve the Low and Ultra Low Emission Vehicle (LEV, ULEV) standards. Experiments were conducted to investigate the impact of various metal oxides in EHC and design parameters to reduce cold-start emissions of a multi-cylinder SI engine. It is observed that EHC reduces cold-start hydrocarbon and carbon monoxide emissions when used with an existing catalytic converter. The maximum CO and HC reductions were achieved with copper oxide as the catalyst in EHC with air injection of 80 1pm for 40 sec after cold start of the engine.