Edge Seal Mounting Support for Diesel Particulate Filter

Abstract

Due to the large sizes, high bulk densities and high thermal expansion coefficients of diesel particulate filter (DPF) substrates, conventional mounting systems fail to provide sufficient mounting pressures. L-Seal mounting supports used in DPF applications not only provide these forces but also cushion the system, accommodating linear tolerance variations in the cone, shell and substrate. The mounting forces provided can be altered by changing various aspects of the seal itself including the material used, its surface characteristics, any heat-treatment applied and its wire geometry. Cyclical compression tests show proportional increases in compressive force per unit of weight, indicating a dimensional consistency in the L-Seal design. The compression characteristics of A286 increase significantly (>20%) during heat treatment as the material precipitate work-hardens. Further heat treatment at DPF regeneration temperatures does not alter the compression characteristics of the material. Combining A286 with a traditional 310 SS allows for generation of optimal spring-back rates otherwise unattained by using than an all 310 or A286 material. The combination stabilizes during cyclic testing, retaining a residual force of more than 50% of its initial value. Within the elastic limits of the L-Seal, the relative loss of force during these tests as a function of the closing gap is constant.