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Current trends in environmental and emissions regulations are driving changes in new engine systems, and increasing the need for more effectively sealed joints in exhaust systems. At the high temperatures in these exhaust systems it is difficult for traditional gaskets to provide an effective seal, as they degrade at high operating temperatures. This paper introduces a coating that has both excellent temperature stability and good compliance, thus forming an excellent sealing enhancement for metallic layers in exhaust system gaskets. Temperature stability data is presented along with sealing data, which illustrate the superior performance of this material compared to current systems.

The paper shows how processing parameters of an injection transfer-moulding machine can be controlled to create and identify moulding faults of valve-stem seals. By controlling the processing parameters to produce typical valve-stem seal moulding faults at the system design stage, causes for waste can be identified. Detailed knowledge of the manufacturing process is fed into a knowledge based SPC quality system to monitor and control the manufacturing process. This information is used in the manufacture of valve-stem seals to improve quality and reduce waste.

The study of material properties is fundamental to the design, analysis, and service life estimation of rubber products. To investigate the usefulness of material test data the paper compares material test properties with those of a moulded product. The material properties include the stress-strain relationship, ageing properties in air and oil and abrasion properties. The study revealed the crucial material properties that directly affect the performance of a valve stem seal (VSS). In addition, a modified least square method is introduced to the Mooney-Rivlin fitting procedure.