Research On Lubrication And Anti-wear Technology For Crankshaft Bearing Of Internal Combustion Engine

The crankshaft bearing is one of the most importance frictions in the internal combustion engine, whose lubricating property can impact on the internal combustion engine work performance directly. With engine output power increasing, engine often works in the high speed and heavy load conditions, the crankshaft bearing would bear heavier loads, and work in the thinner oil film thickness, that means the lubrication conditions and wear will become worse, so it is necessary to study the lubricating property of crankshaft bearing and analyze the reason for bearing wear to propose the optimized design projects.In this paper, according to the Reynolds equation, the elsthohydro-dynamic lubrication model is built which considering many influent factors, such as surface roughness, mixed lubrication, viscosity-pressure effect and elastic deformation. Adopt a new numerical method combing the finite-difference method and finite-element method, and couple analysis the bearing oil pressure, oil film thickness and elastic deformation. The results show that when considering the elastic deformation, the bearing's minimal oil film thickness distributes along the axis no longer a straight line of dynamic lubrication, but a arc with the end extrude and the middle recess, which will lead to the end oil film become thinner and increase the end wear.In order to reduce the adverse effects of crankshaft bearing by the its surface changing under oil pressure, slow down the speed of further wear of the bearing end, this paper put forward a profile modificating method of crankshaft bearing on the basis of EHL analyzing and wear analyzing, which modify the bearing's profile corresponding the journal gradually increased from the end to the middle of cone or arc along the shaft axis, but the journal is still using the cylindrical structure. The research shows that considering the elastic deformation is more actual in the heavy load conditions, and the overall lubrication of profile modificating crankshaft bearing has been effectively improved, the wear of bearing end has slow down significantly, and the bearing working life extend greatly.