Suspended Decoupler: A New Design of Hydraulic Engine Mount

Abstract

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.

Hydraulic engine mounts: a survey

“…By using hyperelastic constitutive relationships the incompressible nature of the rubber materials that make up the bulk of the engine mount are accurately described and the results of such analysis are used directly in previously developed lumped parameter models to describe the dynamic behavior of two distinct hydraulic engine mounts, (Christopherson and Jazar, 2006b). Since then, the model has been accepted by many researchers and used in design, predication, and optimization of HEM, (Shangguan and Lu, 2004;Wu and Shangguan, 2008;Ahn et al, 2005;Mohareri and Arzanpour, 2011;Christopherson et al, 2012).…”

“…Although the assumption of discrete system for a continuous system seems to be over simplifying, this is almost a traditional method of modeling HEM since 1980's. Bernuchon (1984), Corcoran and Ticks (1984) and Singh et al (1992) began to analyze the dynamic behavior of HEM using similar equations, and after three decades, researchers are still using similar methods to analyze, optimize, and control HEM, (Ahn et al, 2005;Christopherson et al, 2012). Several researchers validated the discrete modeling by finite element analysis, computer simulation, experiment, and computational fluid dynamics, (Bathe and Zhang, 2004;Shangguan and Lu, 2004;Zhang and Shangguan, 2006;Tikani et al, 2011).…”

“…However, time response is ill to predict and shows some nonlinear effects of the decoupler such as jump phenomena. Since the reduction of vibration amplitude at steady state condition is considered as the primary function of HEM, not many researchers were concerned about the transient and time response of HEM, and not all of them were successful in mathematical predication, (Singh et al, 2002;Adiguna et al, 2003;He and Singh, 2007a,b;Singh, 2010a, 2010b;Christopherson et al, 2012).…”

Visualization analysis of the working process and dynamic characteristics comparison of a hydraulically damped rubber mount with resonant column channel

“…When the rubber spring is excited by dynamic forces of low frequencies and larger amplitudes, the fluid in the inertia track will flow back and forth between the upper chamber and the lower chamber, and the damping is magnified in the process. When the rubber spring is excited by forces of high frequencies and smaller amplitudes, the dynamic hardening phenomenon occurs, which causes the flux in the inertia track decreased, but the decoupler moves between the lower and upper limit position under the pressure difference between the chambers, and the dynamic stiffness is lowered [20].…”

On the Piecewise Linear Exact Solution

“…To use a soft suspension while protecting the system from high relative displacement, two passive smart systems including hydraulic engine mounts [3][4][5][6][7][8][9][10] and piecewise linear vibration isolators [11][12][13][14][15][16] were introduced to provide a tough suspension at high amplitudes, both with a variety of designs, [9,10,16]. Piecewise linear is a vibration isolator whose system has nonlinear geometric characteristics of sti ness and damping, where nonlinearity is a result of moving among nite number of liner segments, [15].…”