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With the ever increasing need for diesel exhaust particulate filters to meet the stringent emission regulations, it is imperative that a system approach be adopted in the design and optimization of these filters. A performance study is conducted to study the effect of filter parameters like aspect ratio. An extension of this study includes the effect of inlet and outlet cones on the contraction and expansion of flow at inlet and exit of the filter channels. The study covers both cordierite and silicon carbide (SiC) diesel exhaust particulate filters. The experimental data is used to validate the pressure drop models developed previously in the literature. Also the effect of the system parameters on the acoustic performance parameter transmission loss of the particulate filters, Light-, Medium- and Heavy duty truck exhaust mufflers and integrated particulate filter/muffler is investigated.

Advanced substrate design, efficient washcoat/catalyst formulation and robust packaging are critical elements to assure performance and durability of catalytic converters and diesel particulate filters. Radial seals, axial seals and L-seals made of knitted wiremesh are used with conventional mounting systems to provide compressible and durable support cushions for catalyst and filter substrates. Axial and radial mounting forces of the seals are optimized by material type, seal density, wiremesh strand, wiremesh surface profile (flat or round), wiremesh surface characteristics, wiremesh temper, thermal impacts, and wiremesh geometry. Compression characteristics of stainless steel alloy A286 tremendously increase (>20%) during heat treatment as precipitation and hardening occurs. Compression force tends to stabilize during cycling, retaining a residual force. Radial seals provide radial mounting pressure and mat erosion protection.

Due to the large size, high bulk density and high thermal expansion coefficient of the diesel particulate filter substrate; the conventional mounting system cannot provide the necessary radial mounting pressure. Mathematical and experimental results give the vibration and the back pressure force needed to mount the diesel particulate filter in the exhaust system. L-seal mounting support used in diesel particulate filter provides cushion to accommodate the linear tolerance of the substrate and the cone and also the necessary axial and radial mounting forces. L-seal axial and radial mounting forces are altered by type of material, surface characteristics, heat treatment and wire geometry. The proportional increase in compression force per unit weight during cycling shows dimensional consistency of the L-seal. The compression characteristics of A286 tremendously increase (>20%) during heat treatment as precipitation and hardening occurs.