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Advances in Acoustics and Vibration
Volume 2012, Article ID 826497, 11 pages
Research Article

Suspended Decoupler: A New Design of Hydraulic Engine Mount

1MTS Systems Corporation, 14000 Technology Drive, Eden Prairie, MN 55344-2290, USA
2Department of Mechanical Engineering, Milwaukee School of Engineering, Milwaukee, WI 53202, USA
3School of Aerospace, Mechanical, and Manufacturing Engineering, RMIT University, Melbourne, VIC 8083, Australia

Received 28 June 2011; Accepted 14 September 2011

Academic Editor: Mohammad Tawfik

Copyright © 2012 J. Christopherson et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Because of the density mismatch between the decoupler and surrounding fluid, the decoupler of all hydraulic engine mounts (HEM) might float, sink, or stick to the cage bounds, assuming static conditions. The problem appears in the transient response of a bottomed-up floating decoupler hydraulic engine mount. To overcome the bottomed-up problem, a suspended decoupler design for improved decoupler control is introduced. The new design does not noticeably affect the mechanism's steady-state behavior, but improves start-up and transient response. Additionally, the decoupler mechanism is incorporated into a smaller, lighter, yet more tunable and hence more effective hydraulic mount design. The steady-state response of a dimensionless model of the mount is examined utilizing the averaging perturbation method applied to a set of second-order nonlinear ordinary differential equations. It is shown that the frequency responses of the floating and suspended decoupled designs are similar and functional. To have a more realistic modeling, utilizing nonlinear finite elements in conjunction with a lumped parameter modeling approach, we evaluate the nonlinear resorting characteristics of the components and implement them in the equations of motion.