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Over the past several years, monolithic catalytic converters with laminar flow profile are being used by automotive industry. These catalytic converters, though create some turbulence at the inlet, make the majority of the rest of the flow laminar, thereby reducing the mass transfer of the exhaust components to the effective catalytic sites. Improvements were achieved only through the higher cell densities so far. If the design change in the substrates allows the change of exhaust flow from laminar to turbulent, longer residence time can be achieved and more unconverted gases from the core of the channel come closer to the catalyst surfaces facilitating more reaction with the active catalytic sites. The turbulent technology has been successfully developed more recently with metal substrates to get the required turbulent flow characteristics in the substrate channels.

Two and Three Wheeler industry in the Asian region is growing at a rapid pace, as commuting by these vehicles is more affordable and efficient, specially in the developing nations. However, tightening of emission legislations, aimed at creating a cleaner and healthier environment, has led to increasingly demanding efforts required in making more efficient engines / vehicles and also focus on effective after-treatment systems. Catalytic converters, being the most preferred option for after-treatment solutions, play an important role in achieving the desired end results. Over the past several years, monolithic catalytic converters with laminar flow profile were being used by automotive industry. These catalytic converters though create some turbulence at the inlet, make the majority of the rest of the flow laminar, thereby reducing the mass transfer of the exhaust gas components to the effective catalytic sites.

Small Commercial Vehicle (SCV) is an emerging Commercial Vehicle (CV) segment both in India and throughout the world. Vehicles in this segment have diesel engine of capacity less than 1 l and GVW of less than 3.5 t. Normally for the CV, engines are tested on engine dynamometer for emission test, but SCV are tested on chassis dynamometer as they are classified as N1.1 class vehicles. Hence SCV have to follow same emission regulations as diesel passenger cars. The main challenge is to meet BS-IV NOx and PM emission target together with high torque optimization along with required durability targets. This paper addresses this challenge and reports the work carried out on an Indian SCV with 0.7 l naturally aspirated indirect injection diesel engine.