Effects of Multi-order Journal Lobing on the Performance of a Big-End Bearing in a Diesel Engine

An elasto-hydrodynamic lubrication model is used to study the effects of multi-order journal lobing on the performance of a big-end bearing in a turbo-charged diesel engine. The journal has 5 lobes superimposed with 50 lobes of chatter. Results show that any form of lobing has adverse effects on bearing performance, reducing film thickness and increasing oil film pressure. The effects of low and high order lobing are additive, but the bearing system is more sensitive to high order lobing, i.e. chatter. To improve the reliability of big-end bearing systems lobing on the journal should be minimised especially chatter.