Experimental Evaluation of Hydrodynamic Bearings for a High Speed Turbocharger

Many high speed turbochargers are known to operate with limit cycle vibration as a result of fluid-film instability. The goal of this research was to achieve a stable synchronous response with a minimum of self-excited nonsynchronous contribution. Those vibration components excited by the engine harmonics and exhaust pressure pulsations were not the target of this research. This paper will review the experimental results of the fixed geometry fluid-film bearing designs selected to replace the standard stock floating-ring design. In addition, the paper documents a novel radial tilting pad bearing concept that was designed to replace the fixed geometry bearings, with a minimum of modification to the stock bearing housing. A summary of the on-engine testing over the past seven years is documented in this paper.