Development of a Novel Dynamically Loaded Journal Bearing Test Rig

In this work, a dynamically loaded hydrodynamic journal bearing test rig is developed and introduced. The rig is a novel design, using a hydraulic actuator with fast acting spool valves to apply load to a connecting rod. This force is transmitted through the connecting rod to the large end bearing which is mounted on a spinning shaft, simulating a crankshaft journal. The hydraulic actuator allows for fully variable load control and can be used to apply either static load in compression and tension or dynamic loading to simulate engine operation. A variable speed electric motor controls shaft speed and is synchronized to the hydraulic actuator motion to accurately simulate loading from each stroke in a four-stroke cycle. In addition to these dynamically loaded cycles, the journal bearing rig is also capable of controlled static loading. This static loading is used to simulate stop/start engine operation. A high precision torque meter enables direct measurements of journal bearing friction torque, while a laser induced fluorescence (LIF) system is used to accurately measure bearing oil film thickness (OFT). An initial set of data generated in the testing rig is also presented and includes frictional power loss, OFT, and bearing orbit data for several different combinations of bearing and lubricating oil. Results show that the newly developed journal bearing test rig is capable of differentiation based on both changes in hardware and lubricating oil.