Thermal Modeling of Thin Lubricant Film Within Piston Compression Ring and Rough Cyliner Liner Conjuction

Prakash Chandra Mishra

doi:10.3389/fmech.2019.00068

Prakash Chandra Mishra

Open Access

https://doi.org/10.3389/fmech.2019.00068

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Abstract

This work is devoted to develop a transient thermo elastohydrodynamic model for thermal analysis of micro scale oil film with in piston compression ring-liner conjunction. In this paper, heat dissipation through piston to cylinder wall mainly considered via thin film of lubricant on convection and conduction mode. It also includes frictional heat generated due to ring liner co-action while balancing total heat of the engine system. Results presented in this paper show that frictional heating raises additional lubricant temperature of 900 C. Such increase in temperature is one of the reasons for presence of further oil degradation in high pressure zone of engine cycle, which appears between 3000 to 4000 crank location.

Highlights

The internal combustion engine is a thermodynamic system, which is operated in elevated temperature of about 100–500◦C
Estimation of lubricant temperature rise is the prime step for further thermal analysis of any conjunction
This validated model is best investigated for compression ring liner conjuction, including ring global deformation

Summary

INTRODUCTION

The internal combustion engine is a thermodynamic system, which is operated in elevated temperature of about 100–500◦C. The out-of-round bore shape is responsible for a non-uniform gap of conformed ring and is critical to gas blow by Abe and Suzuki (1995) and Okamoto and Sakai (2001) Such contacts are mostly operated in hydrodynamic regime, the friction loss is more in mixed regime because of reduced film thickness due to elevated combustion gas pressure. The film between ring-liner conjunctions varies from 0.5 to 5.0 μm (Mishra et al, 2009) due to action of combustion gas pressure on the back of the ring along with the ring elastic pressure force It leads to lubrication regime transition from hydrodynamic to boundary through mixed.

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