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Application of Diesel Particulate Filter (DPF) will become necessary for trapping diesel particulate matter especially with stringent Emission Legislation of Euro IV and beyond. While developing a DPF, conflicting requirements like low-pressure drop, high thermal durability, high compressive strength, high trapping efficiency and practical regeneration needs to be considered. This paper focuses on the development and optimization of cost effective ceramic based DPFs for a diesel utility vehicle. The effect of DPF diameter, length, cell density and wall thickness on the pressure drop in fresh as well as soot laden conditions are evaluated, based on which the final size of DPF is determined. Special attention to substrate making, coating, canning, temperature and pressure feedback is given. Strategies for DPF regeneration like catalyzed and additive regeneration are evaluated.

The reduction of cold start emission is widely recognized method to meet the stringent automotive emission norms using catalytic converters. One of the effective ways is to use HC traps before the main converters. This system mainly consist of ceramic honeycomb coated with the zeolite molecular sieves which can adsorb HC during the transient cold start period and release to the main converters when it has reached light-off. High catalytic surface area, good HC trapping efficiency, high thermal durability and good mechanical strength are the important properties of zeolite coated honeycombs. They are prepared either by washcoating the zeolite on the substrate or by in-situ crystallization by wet hydrothermal method. The adhesion of the coating is better in the wet hydrothermal process but the honeycombs become mechanically weaker. To overcome this, a new method of forming the zeolite film on the ceramic honeycombs by solid state in situ crystallization has been developed.

Ceramic Hot tubes are developed as a cost effective substrates for 2 and 3 wheelers Catalytic Converter. These are used instead of ceramic honeycomb substrates for the applications where, lower conversion is enough to meet the emission norms. Ceramic hot tubes are more appropriate for 4-stroke two wheelers which are marginally failing to meet Indian emission norms for year 2000. The low thermal expansion cordierite based ceramic hot tubes offer very high thermal shock resistance, high temperature strength, very low back pressure and adequate geometrical surface area. The unique design of this product can withstand severe thermal stresses up to 1200°C. This is required for long durability against mechanical vibrations and extraordinary temperature rise expected in Indian two and three wheelers. Hence ceramic hot tubes have advantage over metallic hot tubes. Under the present work, two different configurations of ceramic hot tubes have been developed.

Extruded ceramic honeycombs are used as substrates for catalytic converter in automotive emission control. The low thermal expansion and thus high thermal shock resistance(TSR) of cordierite honeycomb monoliths are important since monoliths have to withstand severe thermal stresses during the use. Besides thermal expansion, flexural strength and modulus of elasticity are the factors effecting TSR. To meet the demanding requirement of high conversion efficiency with low pressure drop and long durability, the honeycombs of variety of cell density and wall thickness are designed. Various Cordierite honeycombs are extruded and thermal properties are studied and correlated with calculated values and presented in this paper. The thermal expansion is measured in two directions, using a Dilatometer. Anisotropy in thermal expansion is observed in all the samples. Thermal expansion is found to be low along the channels and high across the wall.