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As engine bearings are subjected to higher loading, the oil film thickness in the loading carrying region becomes thinner and thinner. Under the regime of elastohydrodynamic lubrication (EHL), the differences in the elastic deflection of the bearing/journal along axial direction are shown to have significant influence on the bearing performance. The work reported in this paper made use of SABRE-EHL, a predictive tool developed for the study of automotive engine bearings. The influence of axial profile was firstly investigated by the examination of the operating conditions of both the big-end and main bearings of an modern petrol engine. The investigation was then extended to include a sensitivity study, where different types of axial profile were investigated. The impact of these axial profiles on engine bearing performance was then assessed.

Modern engine bearings have been operating under very harsh conditions. Consequently, a bearing wear propagates for a short time and a fatigue sometimes occurs on high loaded region. To reproduce the bearing damage in actual engines, the operating conditions of engine bearing were simulated on a rig test machine. The bearing wear was measured until the fatigue crack occurred in the simulation test. The wear progressed at the edges of the bearing length and the crack also was observed near the edges. The bearing damage is influenced by the bearing design and operating conditions. The experiment was conducted to change the design parameters in conditions. The experimental results were compared to the calculated results based on the elastohydrodynamic lubrication (EHL) theory. The correlation between bearing damage and bearing performance by theoretical analysis were investigated on effects of the design parameters.

The possibility of predicting engine bearing durability by elastohydrodynamic lubrication (EHL) calculations was investigated with the aim of being able to improve durability efficiently without conducting numerous confirmation tests. This study focused on the connecting rod big-end bearing of an automotive engine. The mechanisms of wear and fatigue, which determine bearing durability, were estimated by comparing the results of EHL analysis and experimental data. This comparison showed the possibility of predicting the wear amount and the occurrence of fatigue by calculation.

Engine bearings today are operating under very harsh conditions. Consequently, a wear propagates for a short time and a fatigue sometimes occurs on the bearings. In present study, on the rig test machine, the operating conditions of engine bearing were simulated to reproduce the bearing damage. The bearing wear was measured until the fatigue crack occurred. The bearing wear increased at the edges of the bearing length and the crack also was observed near the edges. The experimental results were compared to the calculated results based on the elastohydrodynamic lubrication (EHL) theory. The correlations between the bearing damage and the bearing performances by the theoretical analysis were investigated.

The behaviour of connecting rod bearings has been studied using a predictive tool which takes into account the influence of the elastic compliance of bearing and housing structure on the hydrodynamic action of the bearing. The first part of the study investigated the effects of different operating conditions on bearing performance. This analysis provided some insight to the problems experienced with some high speed engine connecting rod bearings. The study proceeded to assess the suitability of using a uni-axially loaded test rig for the simulation of bearing behaviour. Results indicated that the pinch effect on the cap half bearing increased with the bearing inertial loading, which correlated well with some of the bearing problems experienced in high speed engines. It was also shown that the behaviour of bearings was significantly influenced by the loading patterns applied to the bearings.

An improved method for oil flow prediction for rigid connecting rod bearings fed by a single hole in the crankshaft has been developed. The paper shows how rigorous film history results can be predicted using rapid methods. This is achieved by structuring the flow equations knowing that the film history flow will be between an upper limit of oil flow based on Reynolds boundary conditions and a lower limit based on feed pressure flow. A large range of variables is considered which includes the position of the feed hole in the crankpin.