A modified design for hydraulic engine mount to improve its vibrational performance

Abstract

Recently, hydraulic engine mounts have been used widely as an effective vibration isolator in automotive engines. They consist of two fluid chambers connected by an inertia track path and a decoupler mechanism with a floating plate. An ideal hydraulic mount should have high stiffness and damping at low frequencies and at high frequencies should act as a good isolator. Despite their acceptable performance, there are some drawbacks including switching, nonlinear behavior of the decoupler plate at low frequencies, and occurrence of the resonance due to the passage of the fluid through the decoupler in the high-frequency range. This paper proposes a new decoupler mechanism where the floating decoupler plate is replaced with a membrane where its tension could be controlled considering the operational frequency. Considering the discrete model of the operating fluid and the continuous model of the membrane, governing equations of the system are derived. By increasing the membrane tension at low frequencies, it is shown that the desired dynamic stiffness and damping can be achieved and the nonlinear switching behavior is eliminated. At the same time, by decreasing the membrane tension at high frequencies, it is shown that there is a significant increase in system compliance, resulting in better isolation. Results also show that the membrane replacement also eliminates the fluid resonances at high frequencies. Finally, the two-objective optimization method of the genetic algorithm is employed to find the optimal values of the membrane tension and the mount parameters. The results show that the proposed mechanism can be used as a suitable alternative to the conventional hydraulic mounts.

Amplitude-Sensitive Single-Pumper Hydraulic Engine Mount Design without a Decoupler

“…In reference [14], a rigid decoupler plate is replaced with a flexible membrane and the tension of the membrane is adjusted, thus adjusting the hydraulic engine mount dynamic stiffness. In the proposed design of reference [14], the decoupler no longer floats.…”

“…In reference [14], a rigid decoupler plate is replaced with a flexible membrane and the tension of the membrane is adjusted, thus adjusting the hydraulic engine mount dynamic stiffness. In the proposed design of reference [14], the decoupler no longer floats. The paper mentions that the flexible decoupler can be made from a thin metal membrane, and its stiffness/tension can be adjusted by using PZT patches.…”

“…The paper mentions that the flexible decoupler can be made from a thin metal membrane, and its stiffness/tension can be adjusted by using PZT patches. The work of reference [14] is very interesting but requires PZT patches, a power supply, sensors, a controller, and a control policy to detect when to increase or decrease decoupler tension. The work is mostly theoretical, and the proposed design has not been verified experimentally.…”

Time domain response analysis of multi-flow channel hydraulic mount

“…Yoon and Singh [8,9] proposed an indirect method based on the quasi-linear fluid system formulation to estimate the power transmitted by a fixed or free decoupled hydraulic mount on a rigid base to compensate for the inaccuracy of the mechanical system model. Farzad [10] proposed a variable stiffness decoupler membrane structure to replace the conventional decoupled membrane channel, and the new decoupled membrane structure can adjust the membrane stiffness according to the excitation frequency to achieve the optimal vibration isolation performance of the mounts. Liao [11] used ABAQUS software to build a fluid-structure coupling model of multi-inertial channel hydraulic mounts and to identify the structural parameters.…”