2006-01-3419
Catalytic Converter Mounting - 50188 Durable Catalytic Converter Mounting with Protective and Support Seals
Sivanandi Rajadurai, Shiju Jacob, Chad Serrell, Rob Morin and Zlatomir Kircanski
ACS Industries Inc. Copyright © 2006 Society of Automotive Engineers, Inc. INTRODUCTION ABSTRACT Close coupled converter systems are becoming necessary in order to meet Ultra low emission vehicles (ULEV), Super ultra low emission vehicles (SULEV) and Partial zero emission vehicles (PZEV) in gasoline and Particulate Matter (PM) regulations in diesel applications (1-6). Since close coupled converters experience severe operating environments, advanced mounting concepts and mounting materials are needed to assure the life of the converter and filter systems (7-
9). Expanding mats, non-expanding mat and wiremesh mounting supports are the commonly used support systems. High flow engines with turbo chargers and super chargers and pulsating engines cause L-sealsprovide combination of axial and radial mounting force for the converter whereas axial
seals are designed to provide only axial supports. L-seals are designed to insert before or after stuffing the substrates in the converter assembly. 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 bymaterial 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. V-seal is an exhaust gas blocking
seal used with stainless steel knitted wiremesh support to prevent exhaust gas from bypassing the ceramic monolith in catalytic converter.
