Diesel Emission Control Devices - Design Factors Affecting Mounting Mat Selection

There is presently a great opportunity for reduction of diesel emissions for heavy duty, automotive, and off-road applications. A wide variety of devices have been designed and further development is proceeding at a fast pace. Technologies include normal oxidation catalysts, particulate filters, and NOx (oxides of nitrogen) traps among others. A broad range of temperature requirements, coupled with large components and the use of steel structures with high thermal expansion coefficient, present unique challenges for designers. This paper explores these design variables in detail, giving examples of where the design problems occur. The analysis points to potential strategies for achieving robust designs within some of the technology areas. Several remaining design problems are discussed. A thermo-mechanical model of the system is presented which helps in understanding the reasons for the design issues. This paper will focus on how the various design factors influence mounting mat selection.