Advanced Methodologies for Close-to-Reality Lab Scale Compatibility Assessment of Sealing Materials and Biofuels

Advanced methodologies for close-to-reality lab scale compatibility assessment of sealing materials and biofuels

Federal-Mogul Sealing Systems GmbH, Bürgermeister-Schmidt-Strasse 17, D-51399 Bruscheid

Abstract

With the worldwide strive of the automotive industry to evaluate and develop alternative mobility concepts, the incorporation of alternative fuels into the current fuel pool gains a strong position in the race to the future. The understanding of the interaction of those novel fuels with engine components, especially sealing materials, is mandatory for the long-life operational capability of an engine system. Current analytical techniques to determine the impact of biofuel systems on the material properties of the sealing materials profoundly lack comparability with engine tests in the field. Major drawbacks of current lab techniques applicable for evaluation of low as well as high volatile biofuels and oil / biofuel mixtures at ambient and high temperatures are highlighted.  Focusing on the Sealing area: Oil, current lab test results with oil being contaminated with 10 vol% E85 e.g. yielded 145 % increase in volume for a standard ACM grade, clearly indicating a destruction of the sealing material [Media: Std. 5W30 engine oil + 10 vol% E85, test conditions: 72 h at 80 °C, pressure vessel]. On the other hand, OEMs do not report any significant issues during engine tests in that context. A new generation of modular lab scale test equipment has therefore been developed, that allows the evaluation of the impact of a wide range of ethanol- and biodiesel based biofuels and oil / biofuel mixtures on the sealing material in an application-like condition. The investigation of state-of-the-art sealing materials in a broad range of test parameters plus a high variability of the test setup allows a simulation of an engine environment on a lab-scale basis. It could be shown, that under a broad range of experimental conditions the maximum volume swell of an ACM sealing material in an engine environment does not exceed 14 %.