Journal Published Online: 30 January 2017
Volume 6, Issue 2

Experimental Validation of a Mixed-Lubrication Regime Model for Textured Piston-Ring-Liner Contacts

CODEN: MPCACD

Abstract

Recent experiments have shown that automotive piston-liner friction may be reduced by up to 50 % if the surface of the liner is laser textured with certain configurations of micro-pockets. It is important to model this behavior to understand and optimize the friction reduction mechanisms that are occurring. However, until now, very few models that predict the lubrication performance of textured surfaces have been successfully validated against experimental data. This is because of the requirement for them to: (1) reproduce experimental configurations with a certain degree of fidelity, (2) conserve mass properly, and (3) account for transient, boundary lubrication conditions. To address this, the current paper presents a comparison between the results from a numerical model, which fulfils these criteria, and an experimental test rig operating under the same conditions. The mathematical modeling is based on the averaged Reynolds’ equation with Patir and Cheng’s flow factors and the p − θ Elrod–Adams mass-conserving cavitation model. Simultaneously to the fluid flow solution, the contact pressures that arise from the asperity interactions are also included into the calculations through the well-known stochastic Greenwood and Tripp model for rough contacts. The experimental data is produced using a reciprocating tribometer, whose contact conditions are closely controlled and accurately mimic those found in an automotive piston–liner conjunction. Data is presented in terms of friction force versus stroke angle, and the similarities and differences between the model and experiment are discussed.

Author Information

Profito, F.
Dept. of Mechanical Engineering, Laboratory of Surface Phenomena (LFS), Polytechnic School of the Univ. of São Paulo, São Paulo, BR Dept. of Mechanical Engineering, Imperial College London, London, GB
Vladescu, S.-C.
Dept. of Mechanical Engineering, Imperial College London, London, GB
Reddyhoff, T.
Dept. of Mechanical Engineering, Imperial College London, London, GB
Dini, D.
Dept. of Mechanical Engineering, Imperial College London, London, GB
Pages: 18
Price: $25.00
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Stock #: MPC20160019
ISSN: 2165-3992
DOI: 10.1520/MPC20160019