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Simulation's drive towards reality boundary conditions is the toughest challenge. Experience has shown that often the most significant source of error in thermal and dynamic analyses is associated within specified boundary conditions. Typically, validating the system by considering both thermal and dynamic loads with predefined assumptions is time consuming and inconclusive when confronted with reality boundary conditions. Thus, the solution comes in unique way of combining thermal and dynamic loads with specified boundary conditions and will convey computational results closer to the real scenario. As a consequence, strain concentrated regions due to thermal expansion are aggregated more, when coupled with dynamic loading. The stress generated by the coupled analyses will prove to be critical in concerning the durability issue of the hot end system. These conditions are evaluated by a finite element model through linear and non-linear approaches and results summarized.

The trend lately has shifted towards usage of thin wall and ultra-thin wall substrates. This change has come to existence due to the increased acting surface area available in these substrates. However these types of substrates have reduced isostatic strength comparatively, reducing its canning durability. This phenomenon has induced a new canning methodology which shall not disturb the substrate integrity during canning and also perform effectively to the requirements. This can be achieved by controlled canning which includes a huge investment and so a new methodology has been devised using the available resources and a partial controlled canning process is established and verified for canning performance and found to be effective. The paper shall include the procedural explanation and a set of results obtained by the new methodology to support its effectiveness.

A compact, knitted, crimped wiremesh mixer disposed in the exhaust system of an internal combustion engine, between the reductant injection and the urea SCR unit, increases the uniformity of the reductant in the exhaust stream by the time the stream reaches the SCR catalysis unit. Wiremesh mixer enhances thermolysis of urea into ammonia and iso-cyanic acid (HNCO). Computational Fluid Dynamics (CFD) modeling shows improved uniformity index from 0.94 to 0.99 within 35 mm travel length due to longitudinal and radial flow of the exhaust gas through the body of the wiremesh mixer. The higher thermolysis and rapid warm-up nature of the wiremesh provides enhanced ammonia production from urea thermolysis. Wiremesh physical attributes such as material composition, geometry and structure, wire diameter, mesh crimp pitch, crimp depth, crimp angle and the contour are optimized for minimum back pressure and maximum mixing efficiency.

Knitted wiremesh along with radial gas tight seals provide reliable mounting system for low temperature underbody converters. The compression characteristics of the wiremesh is modified by wire material, wire diameter, wire geometry, mesh crimp heights; wire density, wiremesh courses per inch, needle count, number of strands, wiremesh temper, wiremesh surface profile and surface characteristics. The radial mounting pressure provided by the wiremesh is matched with the mounting pressure requirement. Wiremesh systems can be tailored to any required radial mounting pressure from conventional to ultra thin-wall substrates. The wiremesh mounting system is proven durable, without any failure on more than 25 million underbody converters in light duty vehicles. Cp and Cpk show the capability of the manufacturing process. Thus the wiremesh mounting support is a viable alternate for low temperature gasoline and diesel applications.