Experimental Analysis of Telescopic Catalytic Converter in a Petrol Engine to Reduce Cold Start Emission

Control of harmful emissions during cold start of the engine has become a challenging task over the years due to the ever increasing stringent emission norms. Positioning of the catalytic converter closer to the exhaust manifold is an efficient way of achieving rapid light-off temperature. On the other hand, the resulting higher thermal loading under high-load engine operation may substantially cause thermal degradation and accelerate catalyst ageing. The objective of the present work is to reduce the light-off time of the catalyst and at the same time to reduce the thermal degradation and ageing of the catalyst to the minimum possible extent. In the present work two innovative approaches namely Parallel Catalytic Converter System (PCCS) and Telescopic Catalytic Converter System (TCCS) have been adopted to reduce the light-off time of the catalyst. The tests were conducted on a 4 cylinder Spark Ignition Engine under cold start condition. It was established that considerable reduction in the light-off time was achieved by using TCCS. Further reduction in the light-off time was achieved by using pre catalysts (40% vol. & 20% vol.) and hot air injection. It has been found that 13% reduction in CO light-off time was achieved with pre-catalyst (40% vol.), 50% reduction with pre-catalyst (20% vol.) and 66% reduction with hot air injector system, when compared to TCCS. Also 14% reduction in HC light-off time was achieved with pre-catalyst (40% vol.), 43% reduction with pre-catalyst (20% vol.) and 63% reduction with hot air injection system, when compared to TCCS. It was also established that light-off time of TCCS can be brought down to 10 seconds using hot air injection.