Search Results

World-wide expansion of ethanol - gasoline blends continue. These fuel blends are complicated by the fact that there is not a fixed formulation that controls the concentration of the ethanol in the gasoline. The study presented examines the effects of varying concentrations of ethanol in gasoline on common static sealing polymers. The polymer families of FKM, HNBR, ACM, AEM and VMQ will be discussed. Data summaries contrasting the effect of ethanol concentration on various mechanical properties by polymer type is presented. Concentrations of 10, 25, 50, 85 and 100% ethanol are examined at one-week and six-week intervals at 23°C.

Current standards for elastomer lip seals recommend plunge ground shafts. The grinding process is, however, expensive and the requirements not always easy to achieve. A more commercially attractive process would be turning, and with modern cutting tools repeatability and reliability are the norm, but the objection is the inbuilt lead which, it is alleged, can promote leakage. This aspect and others have been investigated and the parameters established which give reliable sealing.

Driven by increasing demands to enhance performance while reducing NVH, weight and cost, automotive designers continue to find innovative ways to use thermoplastic materials in under the hood powertrain applications. Even though these applications have proven reliability meeting long term strength and temperature requirements, North American Automotive Manufacturers (OEMs) are reluctant to use thermoplastics in cam cover applications. The current domestic materials of choice are aluminum, magnesium and vinyl ester, even though thermoplastic materials are widely used in Europe and Asia. New technology and supporting theoretical data has not convinced OEMs to develop a composite cover. Pursuing this effort analytically, a cover/sealing system analysis demonstrating the feasibility and competitive advantage is presented.

Engineering plastics are widely used in many tribological applications due to their inherent advantages such as reduced weight, ease of manufacturing, improved chemical compatibility, and damping characteristics. However, the process of selecting an appropriate polymeric material system for a specific application involves significant experimentation.