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C. Lenauer, C. Besser, K. Steinschütz, T. Wopelka, M. Jech, F. Novotny-Farkas, F. Franek:
"Nanoscopic Wear Tests Using Engine Oil Aged With Ethanol Combustion Products";
Talk: 3rd European Conference on Tribology, Wien (invited); 2011-06-07 - 2011-06-09.

Engine tests have shown that ethanol combustion products have an influence on the piston ring - cylinder liner tribosystem [1]. Wear measurement with radioactive isotopes was performed during
these engine tests to determine the amount of piston ring wear. Such tests involving the entire combustion engine have the advantage of being realistic, but are expensive and time-intensive.
Furthermore it can be difficult to separate the impact of individual parameters. Therefore laboratory testing was done to complement the engine tests. Engine oils were aged artificially with the addition
of the specific and relevant individual ethanol combustion products. These aged oils were subsequently used as the lubricant in tribometer tests.
The piston ring-cylinder liner system is an important area for tribological model testing [2]. Using this geometry has the advantage of being closer to the real application than standard ball-on-disc or pin-on-disc tests, while still featuring the desirable characteristics of model testing compared to `real´ engine testing: shorter test durations, closely monitored parameters (such as load, frequency, temperature etc.), easier handling and less expense. However, short term tests under realistic loading conditions typically result in wear in the nanometre range. As the manufacturing process of piston rings already produces roughness and shape irregularities that are much larger, optical
methods for wear measurement are insufficient. Therefore a measurement technique based on radioactive isotopes [3] was used to measure wear in the nanometre range during the tests. Wear during both the engine tests and the tribometer tests was measured with this technique.

Piston ring, wear measurement, model testing, ethanol, biofuels, aged oil, radioactive isotopes

Project Head Friedrich Franek:
Tribologie