In the present analysis, effects of ring profile factor, engine speed, engine load and lubricant viscosity are investigated. Three monograde lubricants and two multigrade lubricants are used in thc theoretical and experimental studies. The friction characteristics of piston rings are compared with experimental results obtained by the floating liner method, which can measure the instantaneous friction force of a piston assembly in a diesel engine under firing conditions.
2. Basic equations
The analytical model of the present study is shown in Fig.1 The local film thickness is defined by following equation making use of symbols depicted in Fig.1.
hT = h + 8δ1 + δr (1)
If there is axisymmetry, then the model can be treated as a one dimensional problem. The average Reynolds equation developed by Patir and Cheng for partially lubricated surfaces of a ring and a liner can be written as follows.
