Rotor dynamic analysis of small vehicle gasoline turbocharger in semi-floating bearings

The critical speed and unbalance response of a small vehicle gasoline turbocharger in semi-floating bearing are analyzed. The dynamical characters of semi-floating bush bearing used in small vehicle gasoline turbocharger were summarized by comparing the structure and shaft rigid mode of semi-floating bush bearings with those of floating bush bearings. The rotor model was built. The first, second and third mode of critical speeds of rotor system were computed, and the changes in the compressor or turbine bushing bearing clearances were analyzed. Compared with the experiment data, the accuracy and the rationality of computation model were verified. The unbalance response and time transient rotor response were also computed.