Influence of lubrication sources location on hydromechanical characteristics of heavy-loaded bearings in thermal engines

The paper considers the technique for determining the movable (holes in the crank bearing) and fixed (grooves on the surface of the pad) lubricant sources for lubricant supply to the heavy-loaded friction type bearing. To calculate the field of hydrodynamic pressures in the bearing lubrication layer, two modifications are taken into consideration: the modification of the algorithm for integrating the modified Elrod equation for the degree of the gap feeling. Further studies showed that developed modifications proved to be quite effective in calculating the characteristics of the lubricating layer both statically and dynamically loaded bearings. However, for the first modification, numerical oscillations of the unknown function at the boundary of the reduction of the lubricating layer were noted, especially for high values of relative eccentricity which is typical for crankshaft bearings of internal combustion engines (ICE). The second modification, for which the finite difference algorithm was used, is characterized by the significant simplicity of numerical implementation and the stability of the iterative procedure. The proposed techniques were used in computational analysis of heavy-loaded tribocontact, which include the connecting rod bearings of the crankshaft. For the KamAZ and DM-21 engines, we considered the influence of the location of lubricant sources on the hydromechanical characteristics (HMC) of heavy-loaded plain bearings. For the KamAZ diesel engine, parametric studies have been carried out, which consisted in determining the most rational location of the lubricant hole in the crank pin. In this case, all the main HMC of the tribocontact were calculated and, based on their analysis, the most optimal solutions were proposed. For the diesel engine DM-21, the authors proposed original schemes of location of partial and complete oil grooves for distribution and for lubricant supply for connecting rod bearings. An additional method of improving hydromechanical characteristics is proved to be the selection of engine oil with improved viscosity-temperature characteristics, which makes it possible to improve the basic hydromechanical characteristics within 10-20%.