Lubrication regime transitions at the piston ring-cylinder liner interface

Abstract

An experimental apparatus and an analytical model have been developed to investigate and determine the lubrication condition and frictional losses at the interface between a piston ring and cylinder liner. In order to obtain a solution for the lubrication condition between the piston ring and cylinder liner, the system of Reynolds and film thickness equations subject to boundary conditions were simultaneously solved. The effects of boundary and mixed lubrication conditions were implemented using the Greenwood -Tripp stochastic approach. The Elrod cavitation algorithm was used to investigate the effects of fluid rupture and reformation at the top and bottom dead centres. The experimental results indicate that the piston ring and liner experience all the different lubrication regimes (i.e. boundary, mixed, and hydrodynamic lubrication) during a stroke. A comparison between experimental and analytical results indicated that they are in good agreement and the analytical model developed for this study can capture the different lubrication regimes that the piston ring and liner experience.Abstract: An experimental apparatus and an analytical model have been developed to investigate and determine the lubrication condition and frictional losses at the interface between a piston ring and cylinder liner. In order to obtain a solution for the lubrication condition between the piston ring and cylinder liner, the system of Reynolds and film thickness equations subject to boundary conditions were simultaneously solved. The effects of boundary and mixed lubrication conditions were implemented using the Greenwood -Tripp stochastic approach. The Elrod cavitation algorithm was used to investigate the effects of fluid rupture and reformation at the top and bottom dead centres. The experimental results indicate that the piston ring and liner experience all the different lubrication regimes (i.e. boundary, mixed, and hydrodynamic lubrication) during a stroke. A comparison between experimental and analytical results indicated that they are in good agreement and the analytical model developed for this study can capture the different lubrication regimes that the piston ring and liner experience.

Tribology of the ring—bore conjunction subject to a mixed regime of lubrication

“…Piston skirt and ring-pack are the primary sources of friction in the engine (around 40 per cent) with losses due to ring-pack being the largest, such that the compression rings are responsible for 4 to 5 per cent of all losses in a typical multi-cylinder IC engine. Given that 4 per cent reduction in parasitic losses translates directly to 1 per cent gain in fuel efficiency, the lack of very detailed analysis, except for a few notable contributions [1][2][3], is rather surprising.…”

“…At the bottom dead centre and during strokes other than power-stroke, the contact force is quite low and, with momentary cessation of entraining motion, boundary interactions are prevalent. In such instances any reduced friction from direct boundary interactions is entirely due to lubricant entrapment by squeeze film action [9] and by non-Newtonian behaviour of very thin adsorbed films at the tips of asperity pairs [2,[10][11][12]. Therefore, a detailed analysis should account for non-Newtonian frictional characteristics of the contact, as well as local deformation of surfaces and squeeze film action (i.e.…”

Wear Analysis of Top Piston Ring to Reduce Top Ring Reversal Bore Wear

“…The model was validated with experimental results obtained from Furuhama and Sasaki [17]. Bolander et al [18] in his study of transition of lubrication regime in the piston ring-Liner surface found that at Dead centres, mostly boundary lubrication is present and asperityasperity contact is there at TDC. Study was experimentally validated with analytical results showed good correlation.…”

Mutual influence of crosshatch angle and superficial roughness of honed surfaces on friction in ring-pack tribo-system

“…the hardness of the material. The normal load F N and contact speed u m are respectively equal to 50 N and 300 rpm [28]. It simulate the piston ring-cylinder bore contact in mixed regime that occur near the Top Dead Center (TDC) and Bottom Dead Center (BDC) [28].…”