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Catalyst in the exhaust system of Light -duty diesel vehicles operating at low temperatures typical of urban driving does not reach light-off temperature. There are options in metallic substrates for close-couple operations for optimum heat utilization to effect higher temperature for oxicat performance and for efficient operation and regeneration of metallic particulate filter, which by itself is an attractive option for EU IV Norm. The present paper gives an account of developments in this field. Also the paper gives an insight into the developments of new innovative metal foil structures for use in petrol and diesel vehicles, which provides enhanced catalytic efficiencies without increasing cell densities.

Development works with metallic open channel PM Filter Catalyst in conjunction with diesel oxidation catalysts and Pre Turbo Catalyst (PTC) on Diesel Cars and Commercial Vehicles with CRDi engines have been reported earlier. These results show that PM conversion efficiency of the order of 40 % can be achieved with PM Filter Catalyst on passenger car diesel engines with continuous regeneration capability. Recently experiments were carried out on a DI engine having distributor type rotary fuel injection equipment with electronic control, turbocharged and inter-cooled, calibrated for BS-III (EURO-III) emissions, with an aim to explore the potential of oxidation catalyst and the PM Filter Catalyst to meet BS-IV (Euro-IV) emission norms. These experiments were carried out with 500ppm sulphur diesel. The results of the tests are presented in this paper. It is seen that with only an oxicat of low level catalyst loading, PM (soluble organic fraction) can be brought down by 20%.

Metallic Catalytic Converters employ alternate layers of flat and corrugated metal foils. To impart higher efficiencies to metallic catalytic converters, there have been progressive developments in the area of foil structures. The constructional details as well as performance behaviour of some of these structures have been reported earlier for automobile applications. In this paper the details of these new structures and the catalyst performance improvement applied to smaller size 2/3 wheeled vehicles are discussed. Transversal Foil Structures (TS) earlier studied and experimented for automobiles have shown improved catalytic performance. Analysis was made for two representative sizes of TS Structure applicable for 2/3 wheelers. It is seen that TS structure improves catalytic converter performance for smaller sizes also. This improvement can be utilized to reduce the Catalytic Converter volume and catalyst loading for same performance as compared to regular substrate.