Energy Efficient Hydrodynamic Journal Bearings by Means of Closed-Loop Controlled Lubrication Flow

State of the art of hydrodynamic journal bearing lubrication is realized by a significant oversupply with lubricant, causing energy losses due to fluid film friction in the unloaded areas of the bearing. Reducing the lubricant flow however may lead to overheating or collapse of the load carrying fluid film, both resulting in a complete failure of the journal bearing. A new approach to safely reduce the lubricant flow is presented in this paper, by using a broadband piezoelectric acoustic emission sensor to detect ultrasonic structure-borne noise, usually caused by metal-to-metal contact at boundary conditions. The method of structure-borne noise analysis has proven to be suitable for detecting the occurrence of solid friction [1–4]. By combining structure-borne noise analysis with a closed loop control of a proportional flow control valve a condition dependent lubricant flow can be set. Thus lubricant friction in the bearing is reduced and additionally electrical energy in the peripheral devices, such as pumps can be saved.