V.K.Parvin et al [68] (2012) from P.D.A. college of engineering in Gulbarga have discussed numerical models of various catalytic converters to reduce particulate matter and back pressure in diesel engines. They used knitted steel wire mesh as filter material as the noble metals are expensive, for effective reduction of HC,CO and NOx. Ceramic monolith, ceramic foam,steel wire meshes are some of the types of materials from which they selected steel wire mesh. They studied experimentally and compared using CFD simulation.