Lubrication Conditions and Development of Pre-failure State of Crankshaft Bearings

Abstract

Most researchers attribute the failure of bearings of a cranked shaft of the engine with the violation of hydrodynamic lubrication. Under normal engine operating conditions, the main oil line maintains the pressure required to ensure optimal lubrication of the friction surfaces. As the bearings of the crankshaft wear out and, consequently, increase the gaps in them, the flow of oil through the bearings is facilitated; in this regard, the pressure in the oil line decreases. The pressure and oil flow through the connecting rod bearings are due to a large number of factors: the performance of the oil pump, the operating mode of the engine, and the degree of wear, as well as design features of lubrication systems, individual components and parts, the method of supplying oil to them. In addition, the oil flows in the rotating crankshaft are subject to centrifugal forces, resulting in pressure loss in the channels up to 50% of the nominal value, which leads to a decrease in oil flow through the connecting rod bearings. Negatively affect the modes of rupture of the oil flow supplied to the connecting rod cavity, which actually precede the failure of the crankshaft bearings. Their research is devoted to this work.