Study of Break-In Process and its Effects on Piston Skirt Lubrication in Internal Combustion Engines
Author(s)Meng, Zhen; Zhang, Linfeng; Tian, Tian
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The piston skirt is one of the main contributors to the total mechanical loss in internal combustion engines. Usually, the skirt friction experiences a rapid change during the break-in period largely due to the wear of the machine marks or roughness against soft coatings. It is thus important to consider the effect of the change of the roughness for a realistic prediction of the piston skirt friction and system optimization. In this work, an existing model of piston skirt lubrication was improved with the consideration of a breaking in process for the most commonly used triangle machine marks. A new set of flow factors in the averaged Reynolds equation were analytically derived for the trapezoid shape formed after wear of the original triangle shape. A new asperity contact model was developed for the trapezoid shape. The calculation results reflect the trend of friction mean effective pressure (FMEP) during break-in in an engine test and showed quantitative agreement under the same amount of wear.
DepartmentMassachusetts Institute of Technology. Department of Mechanical Engineering
Meng, Zhen et al. "Study of Break-In Process and its Effects on Piston Skirt Lubrication in Internal Combustion Engines." Lubricants 7, 11 (November 2019): 98 © 2019 The Authors
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