Abstract
Goal of the present study was to develop a short test method, which accurately simulates corrosion effects seen in cold-running engines fuelled by ethanol. A representative corrosive medium test mixture was developed based on 5W30 oil mixed with ethanol, water and acetic acid. Parts to be tested were treated in this mixture at 80 °C for 50 hours, and after the test duration weight loss per unit area as well as corrosion depth were registered. The developed test method allows for quickly assessing the relative corrosion resistance between different PCU materials, and thus helps with the identification of weak points in the engine and the development of more corrosion-resistant construction materials and functional coatings. The present test is aimed to quickly screen materials and rank them against each other in terms of their corrosion resistance towards ethanol fuel oxidation products. The test is carried out under static test conditions at ambient pressure and without any relative movement of the components. Currently, no standardized test method is available to assess the corrosion resistance of PCU components with respect to oxidation products for ethanol fuel or conventional fossil fuel with ethanol additions. The present test has been developed in-house and will be applied across the range of engine components that MAHLE produces to support the development of new materials. First ranking results for different materials are presented.
KEYWORDS – corrosion, ethanol fuel, power cell unit, engine components, materials