Oil Splash Simulation in Final Drive with Overset Mesh 2019-26-0274

The reduction of CO₂ emission is one of the greatest difficulties to the automotive industry. An optimally designed driveline with effective cooling and lubrication gives significant CO₂ decrease. The cooling and lubrication performance is critical to the functionality and durability of vehicle drive units, for example, transmissions and differentials. Final drive incorporates gears, bearings and shafts to transmit power from the engine to the wheels. Final drives depend on oil splash where the oil stream is driven by the rotation of the gears and guided to critical positions. Splash lubrication is hard to predict because of the chaotic nature of the stream, and therefore development of the lubrication system is mostly done experimentally in rig tests. The utilization of CFD simulation with superior computer performance has made it conceivable to predict and optimize the oil lubrication and cooling performance of final drive.

CFD method is developed that incorporates transient multiphase flow (oil and air) simulation utilizing Volume of Fluid (VOF) method and Overset mesh. The gear interaction is modeled using Overset mesh. Fluid interaction with the gears also modeled simultaneously.

Developed CFD method is validated with the experimental results of oil splash representation and churning losses in final drive housing. The developed CFD method is a compelling method to assess more design alternative e.g. gear designs, improved oil quantity and flow at various locations. It can be useful in the early stages of the product development.