Experimental Investigation of Cold Start Emission using Dynamic Catalytic Converter with Pre-Catalyst and Hot Air Injector on a Multi Cylinder Spark Ignition Engine

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 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 reduce the thermal degradation and ageing of the catalyst to the minimum possible extent by adopting an approach with Dynamic Catalytic Converter System (DCCS). The emission tests were conducted at the cold start of a 4 cylinder spark ignition engine with DCCS at different positions of the catalyst at no load conditions. Also emission tests were conducted with pre-catalysts of 20% volume and 40% volume of the main catalytic converter and with air pre-heater at the exhaust manifold prior to main catalytic converter. It was established that considerable reduction in the time to light off was achieved by using DCCS and light-off time was further reduced by using pre-catalysts and air pre-heater as compared to the conventional catalysts. It was observed that DCCS with air pre-heater delivering air at 80°C and at 20lpm air flow rate brings down the time to light off to 10 seconds.