Experimental Analysis of Telescopic Catalytic Converter in a Petrol Engine to Reduce Cold Start Emission Ganesan.M a , Sendilvelan.S b* Professor in Mechanical Engineering, Dr.M.G.R Educational and Research Institute, University, Chennai-600095, India. a ganesh_maha@yahoo.com, b sendilvelan63@yahoo.com Keywords: Cold Start Emission, Catalytic Converter, Pre-Catalyst, Light-off Temperature. Abstract. 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. Introduction Air pollution generated from automobile sources is a serious problem to human kind. During the last 60 years the world vehicle fleet has increased from about 40 million vehicles to over 1 billion. The figure is projected to double in another 20 years. Emission in Internal Combustion Engines (I.C. Engines) affects the quality of air leading to global warming and degeneration of human health. Vehicles emit the harmful exhaust emissions within the first 2-3 minutes after engine cranking following a “cold-start”. During the cold start, rich mixture is supplied to the engine and oxygen supply is insufficient for complete combustion of hydro carbon. Due to incomplete combustion, potentially harmful products like un-burnt hydrocarbons and carbon monoxides are produced. Catalytic converters are effective in reducing the emissions only after they reach the “light-off” temperature, at which the catalysts become active, normally at around 250-300°C (Presti, M et al., 2013). The time period at which the catalyst becomes active is referred to as light-off time. The catalyst is said to be active for a particular emission when the conversion efficiency reaches 50% (Oliver, J et al., 1999). Till the catalyst attains light-off, the harmful pollutants go out of the tail pipe untreated and such emission is referred to as cold start emission (Rohart, E, et al., 2004). Nearly 60 to 80% of the engine out emission occurs in the cold start. Efficiency of a conventional catalytic converter declines very steeply at low temperature. During cold start and warming period the converter efficiency is very close to zero (Bielaczyc, P, et al., 2013). To reduce the cold start emission, light-off temperature has to be attained rapidly. There are active and passive methods for rapid light-off. The active methods include electrically heated metal catalyst, catalyzed fuel burner, International Journal of Engineering Research in Africa Submitted: 2016-01-18 ISSN: 1663-4144, Vol. 25, pp 28-35 Revised: 2016-06-08 doi:10.4028/www.scientific.net/JERA.25.28 Accepted: 2016-06-08 © 2016 Trans Tech Publications, Switzerland All rights reserved. No part of contents of this paper may be reproduced or transmitted in any form or by any means without the written permission of Trans Tech Publications, www.ttp.net. (#68727704, Chennai, India-19/07/16,10:16:13)