Passenger vehicle turbochargers (TCs) offer increased IC engine power and efficiency. TCs operate at high rotational speeds and use engine oil in their bearing support system comprising of inner and outer lubricant films acting in series. The hydrodynamic bearings induce instabilities, i.e. subsynchronous shaft motions over wide operating speed ranges [1]. Yet, the motions are well bounded limit enabling the TC continuous operation [2, 3]. Due to the lack of accurate and efficient predictive nonlinear tools, turbocharger rotordynamic design followed, until recently, costly test stand iteration [3]. Presently, a rotordynamics model coupled to a bearing lubrication model calculates the nonlinear motions of TCs and delivers predictions of TC shaft dynamic response for practical conditions [4–6]. The software emulates a virtual laboratory, effectively aiding to design better TC products with increased reliability in a shorter cycle time. Predictions of the nonlinear model compare well with recorded TC shaft motions, both in amplitude and frequency content. The benchmarking lends credence to the validity of the integrated computational model.
The Investigation into the Tribological Impact of Alternative Fuels on Engines Based on Acoustic Emission