Changing Supplying Oil and Connecting Rod Bearings Conditions of the Crankshaft of an Internal Combustion Engine in Operation

Author Name(s): Ilnur R. Akhmetzyanov, Alexander T. Kulakov, Elena P. Barylnikova, Irina P. Talipova
Author Email: 692401@mail.ru

 

The main reason for reducing the life of the failed engines in operation is the cranking of the connecting rod inserts. Crankshaft bearings operate under constantly changing loads and speeds, as well as with varying amounts, pressure, temperature and viscosity of the oil supplied to them, which ultimately leads to increased wear on the shaft surface and liners. As the technical condition of the internal combustion engine worsens, stabilization of the available and required oil consumption is not structurally provided, which leads to failures and the need for expensive overhauls. Investigating the reasons for cranking the bushings [1], found that through the crankpin on which the bearings were turned, less oil passed. As a result of the analysis, the need for a deeper study of the conditions of the lubrication process, its influence on the reduction of the engine resource and the need for its stabilization is revealed. A theoretical analysis of the reasons leading to the condition of the rupture of the oil flow to the connecting rod bearings of the internal combustion engine is carried out. The test results of the study of the influence of liner wear on the crankshaft lubrication conditions are presented.

Introduction

The reliability of the crankshaft bearings is achieved by organizing the supply of a sufficient amount of oil to the connecting rod bearings. The main parameter that determines the modes of lubrication is the pressure, which at all steady-state operating modes of the engine should ensure continuity of flow in the channels to the connecting rod bearings [2, 3]. To assess the oil pressure in the supply channels to the connecting rod bearings, we consider the process of oil movement through the channels of the crankshaft bearing assembly using the KamAZ-740 diesel engine as an example [4]. In the engine understudy, oil is supplied to the connecting rod bearings (Fig. 1) from the annular channel 1 in the main liner through the channel in the main neck and cheek 2 and the centrifugal dirt catcher 3.

Conclusion

The operational wear of the crankshaft bearings can lead to the rupture of the oil flow to the connecting rod bearings of the engine. If, at normal clearances, the available oil flow through the channels of the main bearings is sufficient to pump the required oil flow through the connecting rod bearings, then with an increase in the clearances, the required oil flow into the connecting rod bearings can be several times higher than the available oil flow through the main bearings. The study made it possible to establish the limiting value of pressure in the engine lubrication system, which can be described as a critical pressure point. Preventing the pressure in the lubrication system below 0.26 MPa allows you to save a margin in the performance of the available oil flow over the required flow rate through the connecting rod bearings of the crankshaft and thereby eliminate their premature failure

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