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Modern High-Speed Diesel (HSD) engines place increasing demands on engine components. Specifically, for connecting rod bearings there is a requirement to endure increased peak cylinder pressures and the resulting loads transmitted through the connecting rods to the crankshaft. In addition to these high loads, the operating environment for bearings is becoming more aggressive. Reductions in oil film thickness combined with the move towards lower viscosity oils means that the seizure and wear resistance of the bearings play a crucial role in modern engine development. In order to attend to these demands, MAHLE has developed a novel high-performance polymer coating containing lubricant-filled microcapsules. The Microcapsules are designed to rupture during nascent scuff and high wear events and consequently release the contained lubricant ‘on demand’. This introduces additional lubrication when required to prevent seizure.

The implementation of legislations to ban the usage of lead as an alloying element in internal combustion engines and incrementally reducing emission output is having a fundamental impact on the design and function of half bearings. It has been witnessed that bearing operating environments are becoming more aggressive as there is a trend for manufactures to adopt various technologies and strategies such as start stop / hybrid systems, downsizing and low viscosity oils in an effort to improve fuel consumption and reduce emission output. Engine bearings normally operate under hydrodynamic lubrication, however the consequence of implementing such technologies, is that the bearings have to operate under mixed or boundary lubrication for increased durations without compromising the bearing system durability. It is considered that the commercial vehicle sector will additionally start to adopt these technologies and strategies in an effort to achieve the specified targets.