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New Polymeric Coating on Sputtered Bearings for Heavy Duty Diesel Engines
Abstract:
Worldwide emissions standards are becoming increasingly rigorous, and this leads to more complex engine demands. Several new PCU (Power Cell Unit) technologies are being applied to cope with these demands. This means engine parameters are changing, e.g. higher EGR (Exhaust Gas Recirculation) rates, higher PCP (Peak Cylinder Pressure), lower viscosity oils, higher oil contamination and soot. Therefore the operating conditions for the bearings have drastically changed, leading to an environment prone to seizure occurrences.
There is a clear demand for seizure resistant bearings motivated mainly by the increased engine complexity described above. Therefore for HDD (Heavy Duty Diesel) applications the PCU robustness should not be compromised also in terms of wear and fatigue resistance. The polymeric coating developed by MAHLE was applied over a sputtered layer and has demonstrated to be a suitable solution to attend to the application demands. The seizure and wear resistance were strongly reinforced with the use of a polymeric coating when compared to a typical Al-Sn sputtered layer. The functional polymeric layer remains in place after long durability tests in a demanding HDD engine.
This paper shows detailed bench and engine test results achieved with this new product to support the conclusions.