Analysis of the tribological behaviour of the lubricated contacts of a connecting rod equipped with a direct pin oiling gallery

This paper describes a methodology for identifying a suitable design of a Direct-Pin-Oiling (DPO) gallery, drilled through the conrod shank of a high-performance internal combustion engine, to directly supply pressurized lubricant to the piston pin/small-end interface. Initially, a multibody elastohydrodynamic model is set up to analyse the tribological behaviour of conrod bearings, when considering a standard configuration employing a passive lubricating hole drilled on the top of the small-end. Then, a preliminary DPO gallery is introduced to examine how it affects the oil flows at lubricated interfaces and their tribological behaviour. The numerical results and parallel experimental evidence underline the need to modify the initial configuration of the DPO gallery and a more performing gallery design is proposed.