In today's competitive market, noise and vibration are among the most important parameters that impact the success of a vehicle. In body-on-frame construction vehicles, elastomeric body mounts play a major role in isolating the passenger compartment from road noise, harshness, shake, and other vibrations in the chassis as well as improving ride quality across a wide frequency range.
This paper describes the work carried out to design a fluid filled mount with high lateral stiffness that can alter the perceived Noise, Vibration and Harshness (NVH) performance of current production body-on-frame trucks. It was found that the quietness and ride qualities can be significantly improved by positioning the glycol-filled mounts at the anti-node of the frame first vertical bending mode; under the C-pillar intersection with the frame. The performance of mounts in this area is known to be critical to ride quality. Benefits such as reduced vehicle noise, vibration levels, and ride quality, especially on moderate to rough roads, are attainable through the proposed design approach of the hydraulic body mount.
Several experimental mounts were designed and prototyped for on-vehicle evaluation; an aggressive experimental library of tuning parts with sufficient range of lateral to vertical rate ratios were built and evaluated. As an aid to understanding, the details of each design option will be presented along with typical performance characteristics of the mounts. The evaluation results demonstrate that hydraulic mounts with high lateral stiffness provide a technical solution to control noise and mitigate shake. Automotive manufacturers can utilize this cost-effective isolation technique as an alternative to frame changes, shock absorber tuning, tuned mass dampers, and alternate suspension design.
The rationale for the use of body mounts with hydraulic damping for pickup trucks is well covered in [1]. This effort is to demonstrate that hydraulic body mounts can be even more effective with high lateral stiffness.