Developing an approach utilizing local deterministic analysis to predict the cycle friction of the piston ring-pack in internal combustion engines

Nowadays, a rapid growth of internal combustion (IC) engines is considered to be a major contributor to energy crisis. About 20% of the mechanical loss in internal combustion engines directly goes to the friction loss between piston ring pack and liner finish. A twin-land oil control ring (TLOCR) deterministic model was developed by Chen et al. and it helps the automotive companies investigate the effects of liner finish, rings, and lubricants on friction and oil control of the TLOCR [2]. This work focuses on application of the TLOCR model and extension of the deterministic model to the top two rings. First, there are some practical challenges in the application of Chen's TLOCR deterministic model. Due to different wear condition on the same liner, surface roughness varies from spot to spot. A small patch of measurement cannot provide enough information and the change of plateau roughness makes the contact model unreliable. As a result, a multi-point correlation method was proposed to combine the information of different spots from the same liner and this method was shown to give better match to the experimental results. A top-two-ring lubrication cycle model was developed based on the multiphase deterministic model by Li. et al [30] and previous top-two-ring lubrication model by Chen. Et al [2][31]. The model is composed with two parts. First, the deterministic model is used to generate a correlation between the hydrodynamic pressure/friction and the minimum clearance with prescribed oil supply from the deterministic oil control ring model. It was found that within reasonable accuracy, the gas pressure effect on the hydrodynamic lubrication of the top two rings can be decoupled from the hydrodynamic lubrication. Thus, only single-phase deterministic model was needed to generate the correlation. This decoupling significantly reduces the computation time. Then, a cycle model was developed utilizing the correlation of hydrodynamic pressure/friction and the minimum clearance. The cycle model considers the effect of gas pressure variations in different ring pack regions as well as the dynamic twist of the top two rings. Finally, the models were used to examine the friction and lubrication of three different liner finishes in an actual engine running cycle.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Mechanical Engineering.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2013

Author dc:creator

• Liu, Yang, Ph. D. Massachusetts Institute of Technology

Advisor dc:contributor.advisor

• Tian Tian.

• Mechanical Engineering.

Statement dc:rights

• M.I.T. theses are protected by copyright. They may be viewed from this source for any purpose, but reproduction or distribution in any format is prohibited without written permission. See provided URL for inquiries about permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/82299

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/82299