Table of Contents
Smart Materials Research
Volume 2013, Article ID 831017, 21 pages
Review Article

MR- and ER-Based Semiactive Engine Mounts: A Review

1Mechanical Engineering, University of Toledo, Toledo, OH 43606, USA
2Mechanical Engineering, Northern Arizona University, Flagstaff, AZ 86011, USA
3Mechanical Engineering, California State University Fresno, Fresno, CA 93740, USA
4Cinetic DyAG Corporation, 23400 Halsted Road, Farmington Hills, MI 48335, USA

Received 9 October 2012; Accepted 7 November 2012

Academic Editor: Mehdi Ahmadian

Copyright © 2013 Mohammad Elahinia 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.


Hybrid propulsion technologies, including hybrid electric and hydraulic hybrid, equip vehicles with nonconventional power sources (in addition to the internal combustion engine) to provide higher fuel efficiency. However, these technologies tend to lead to higher levels of noise, vibration, and harshness in the vehicles, mainly due to the switching between the multiple power sources involved. In addition, the shocks and vibrations associated with the power sources switching may occur over a wide range of frequencies. It has been proven that passive vibration isolators (e.g., elastomeric and hydraulic mounts) are unable to mitigate or totally isolate such shocks and vibrations. Active mounts, while effective, are more complex, require significant power to operate, and can lead to system instabilities. Semiactive vibration isolators have been shown to be as effective as active mounts while being less complex and requiring less power to operate. This paper presents a review of novel semiactive shock and vibration isolators developed using magnetorheological and electrorheological fluids. These fluids change their yield stress in response to an externally applied magnetic and electric field, respectively. As a result, these fluids allow one to transform a passive hydraulic vibration isolator into a semiactive device.