Modal and random vibration analysis of pneumatic actuator of wastegate turbocharger using finite element method

Abstract

Turbocharging is the most common power augmentation method used in both spark and compression ignition engines. However, the excessive turbo boost can end up in risking the intake manifold pressure which can negatively affect the performance of an engine. Therefore, the modern turbochargers are developed with wastegate which effectively controls the turbine speed and limits the excessive turbo boost bypassing the fraction of exhaust gas. In this work, the modal and random vibration analysis of the pneumatic actuator assembly of a wastegate turbocharger is presented. The turbocharger was substituted by a dummy vibratory shaker table with test spacers and a subassembly was mounted on the shaker table. The model of the actuator was designed in Creo© software and finite element analysis was performed in the commercially available software package ANSYS©. The materials used for critical components of the assembly were Structural Steel and SAE1008 Steel for the bracket and CAN respectively. Initially the structural load in the form of bolt pretension was applied at bolted joints and prestressed modal analysis was performed. The results of modal analysis were further utilized for random vibration analysis. The PSD acceleration input was given to the shaker table and output response at critical locations was analyzed. Subsequently, the results were quantitatively analyzed for modal participation factor variation, natural frequencies and PSD equivalent stresses in the actuator assembly. © 2025, Association of American Publishers. All rights reserved.