On Dynamics and Stability of the Automotive Engine Turbocharger Rotor Supported by the Electrodynamic Passive Magnetic Bearings

Abstract

In the paper dynamic investigations on the automotive turbocharger rotor-shaft supported on the electrodynamic passive magnetic bearings (EDPMB) and on the traditional floating-ring journal bearings have been carried out using a computer model. The results of computations obtained for the two mutually compared kinds of suspension are demonstrated in the form of Campbell diagrams and amplitude-frequency characteristics. Here, the main attention is focused on resonant-free operation ability assured by the support on the EDPMBs. Moreover, conditions of stability for the support on the journal bearings and on the EDPMBs have been investigated by means of the eigenvalue analysis. There is studied an influence of skew- symmetrical dynamic properties of the both kinds of rotor-shaft suspensions caused by the bearing stiffness negative cross-coupling terms as well as by the gyroscopic effects which are particularly severe at turbocharger high rotational speeds.