Influence of Microtexture’s Parameters on Improving the Lubrication Performance of Crankpin Bearings in Engine

<div>The force of the solid contact (<i>F<sub>sc</sub> </i>) between the bearing surface and the shaft surface and the friction force (<i>F<sub>fri</sub> </i>) generated in the crankpin bearing have a great influence on the lubrication performance of the crankpin bearing in the engine. Therefore, the micro-circular texture (MCT) has been proposed and designed on the bearing surface of the crankpin bearing for ameliorating its lubrication performance. To evaluate the effectiveness of MCT in detail, based on the lubricating model of the crankpin bearing under the impaction of external load <i>F</i> <sub>0</sub>, the influence of the density, depth (<i>h<sub>MCT</sub> </i>), and radius (<i>r<sub>MCT</sub> </i>) of MCT on the characteristics of the pressure (<i>p</i>) of oil film, thickness of oil film (<i>h</i>), force of solid contacts, and force of the friction in the crankpin bearing are also investigated, respectively. An algorithmic program written in a MATLAB environment is then applied to simulate the lubrication equations of the crankpin bearing and MCT. Some outstanding results of the study have been achieved as follows: (i) all the results of <i>p</i>, <i>h</i>, <i>F<sub>sc</sub> </i>, and <i>F<sub>fri</sub> </i> with MCT are significantly improved in comparison with those without MCT; thus, the lubrication performance of the crankpin bearing with MCT added is better than that without MCT. (ii) To better improve the lubrication performance of the crankpin bearing, the density of MCT 12 × 6, depth of <i>h<sub>MCT</sub> </i> = 15 μm, and radius of 0.25 < <i>r<sub>MCT</sub> </i> < 0.5 mm should be used for designing MCT. (iii) The MCT in the hydrodynamic lubrication mode improves the lubrication performance of the crankpin bearing lower than the MCT in the mixed lubrication mode. Therefore, MCT should be designed over a portion of the bearing surface in the mixed lubrication mode. This not only reduces the complexity and manufacturing cost of MCT but also improves the lubrication performance of the crankpin bearing.</div>