Comparison between experimental film thickness measurements and elastohydrodynamic analysis in a connecting-rod bearing

Abstract

This paper describes the experimental measurements and the theoretical calculations of oil-®lm thickness in a dynamically loaded connecting-rod big-end bearing. F our eddy current gap sensors for each bearing are used to measure the oil-®lm thickness and to deduce the bearing trajectories. Experimental data for crankshaft main bearings are easy to obtain but connecting-rod bearings are more dif®cult to control due to the dif®culty of installing instrumentation on connectingrods that are rotating and reciprocating. The solution uses a mechanical linkage ®xed under the piston axis. The elastohydrodynamic model considers connecting-rod elastic deformations. The calculation process uses ®nite element and N ewton±R aphson methods for the numerical analysis. Comparisons of both the load and crankshaft speed effects are made between experiment and the theory. Keywords: elastic engine bearing, connecting-rod bearing, experimental oil-®lm thickness measurement, ®nite element method NOTATION e x horizontal eccentricity (m) e y vertical eccentricity (m) h oil-®lm thickness (m) p hydrodynamic pressure in the ®lm (Pa) t time (s) y angular abscissa in a bearing (rad) m lubricant dynamic viscosity (Pa s) o crankshaft rotating speed relative to the connecting-rod (rad/s)

Conformal elastohydrodynamic lubrication analysis for engine bearing design: A brief review

“…Comparisons of calculated and experimental results with various degrees of sophistication appear throughout several references [4], [20], [22], [28], [46], and [47].…”

Analysis and Experimental Validation of the Tribological and Dynamic Characteristics of Journal Bearings

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Development of an Experimental Device for Studying Real Connecting-Rod Bearings Functioning in Severe Conditions

“…To assist designers in this effort, it is important to analyze and to understand engines bearing mechanical behavior. Therefore, many experimental studies have been undertaken in the last 20 years [1][2][3]. Because of the great complexity of the con-rod bearing real environment, no experimental tests have been realized in realistic and severe conditions.…”