The development of combustion engines is focused particularly on the reduction of CO_2 emissions. To develop more efficient engines, downsizing is used leading to increased combustion peak cylinder pressures which impact on the tribological conditions of the base engine's bearing components. Higher operating temperatures require bearing materials with improved corrosion resistance especially for the connecting rod small end bushing. Increased mechanical loads require the use of materials with sufficient fatigue resistance. This is combined with the demand for improved wear resistance to enable start-stop functionality. Beside the impact of efficiency improvements driven by other areas of the engine, the bearings themselves can also contribute to friction reduction. This is achieved directly on the one hand by optimization of hydrodynamic friction power loss and indirectly on the other hand, by minimizing the power loss caused by excessive oil drainage from the bearings increasing the amount of oil flow required from the oil pump.
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