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Effects of lubricant viscosity on the mixed lubrication of a piston ring pack in an internal combustion engine
Author(s) -
Hamatake Toshiro,
Wakuri Yutaro,
Soejima Mitsuhiro,
Kitahara Tatsumi
Publication year - 2003
Publication title -
lubrication science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.632
H-Index - 36
eISSN - 1557-6833
pISSN - 0954-0075
DOI - 10.1002/ls.3010150202
Subject(s) - lubricant , shear thinning , piston ring , lubrication , piston (optics) , materials science , viscosity , asperity (geotechnical engineering) , rheology , composite material , friction loss , shear (geology) , internal combustion engine , mechanics , mechanical engineering , ring (chemistry) , engineering , chemistry , physics , organic chemistry , wavefront , optics
A theoretical analysis is presented of the mixed lubrication of a piston ring pack. The analysis comprises Patir and Cheng's average flow model and Greenwood and Tripp's asperity interaction model, and is developed to consider the shear thinning effect of a non‐Newtonian fluid, multigrade lubricant. The friction characteristics of the piston ring pack for both monograde and multigrade lubricants are investigated. It is found that a decrease in the lubricant viscosity is effective in reducing the friction loss, although this increases the boundary friction at the beginning of the expansion stroke. The friction characteristics are markedly affected by the shear thinning effect when multigrade lubricants are used.