A Magnetorheological Vibration Isolator for Hydraulic Hybrid Vehicles

Abstract

This paper presents the results of vibration isolation analysis for the pump/motor component of hydraulic hybrid vehicles (HHV). The hybrid subsystem can potentially improve the fuel efficiency of the vehicle by recovering some of the energy that is otherwise wasted in friction brakes. High pressure hydraulic fluid “assists” the engine in the initial acceleration period. Noise and vibration are an issue with these systems due to the variable hydraulic loads that are applied to the regenerative hybrid element. This study looks into the possibility of reducing the transmitted noise and vibration to the vehicle’s chassis by using smart magnetorheological (MR) dampers. MR dampers utilize MR fluid which is made of pure iron particles suspended in a carrier fluid. MR fluids deliver variable yield stress under the effect of a controllable electromagnetic field. To this end, an MR damper is modeled and simulated. In the simulation both shock and vibration loads are considered. The simulation results are compared with the performance of regular elastomer isolators. It is shown that the MR damper can effectively reduce the vibration for different working cycles of the regenerative system.