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This paper reports on the development of a passive exhaust cooler for General Motors diesel vehicles to lower engine exhaust gas temperatures at the tail pipe exit. Such a cooler is needed to lower tail pipe gas temperatures that can exceed 600°C during regeneration of the particulate filter. The use of a particulate filter is driven by emissions regulations for diesel trucks since the 2007 model year in the U.S. The cooler should also find application in vehicles outside the U.S. as emissions requirements necessitate the use of particulate filters globally. Key features of this device include: no moving parts, high reliability, low skin temperature, low pass by noise, low manufacturing cost and ease of packaging. While lowering tail pipe gas temperatures to acceptable levels, the benefits of this cooler also extend to reduced fuel consumption and improved engine oil life by avoiding starting and stopping regenerations during city driving.

Over the past 20 years, polyvinyl chloride (PVC) has almost replaced metal in stationary glass reveal moldings with dramatic part cost savings on cars and trucks world-wide. The process of assembly is generally simple and convenient but to replace a reveal molding can be difficult. Many times, in order to replace the molding, it may also be necessary to replace or reseal the glass. In short, PVC reveal moldings, relatively inexpensive parts, are very expensive to service. Outside of general assembly and processing issues, there are 5 variables that may cause a failure in the performance of a stationary glass reveal molding. They are as follows: material degradation, crystallization, plasticizer loss, material properties, and molded-in stress. Because of modern standard PVC formulations and the material requirements of most automotive companies, material degradation, crystallization and plasticizer loss do not commonly cause failure. Material properties and molded-in stress do.