Vibration Isolation Control for Hydraulic Hybrid Vehicles

Abstract

In recent decades, many types of hybrid vehicles have been developed to compensate for the limited sources of oil and gas production. Gasoline-electric hybrid technology shows a significant improvement in fuel efficiency for small and medium-sized passenger vehicles. However, that hybrid type is not economically beneficial for larger vehicles due to large, harmful and expensive battery packs. Hydraulic hybrid technology has been found effective for heavy duty vehicle because of its high power density. Other advantages of hydraulic hybrid are the lower cost and environmental friendliness over the electric batteries. The potential achievement in fuel efficiency has been proved in several studies and experiments by different schools, institutes and laboratories. The only problems preventing this hydraulic hybrid technology going to the market are noise and vibration involving with the hydraulic system. This study focuses on using magnetorheological (MR) technology to reduce the noise and vibration transmissibility from the hydraulic system to the vehicle body. MR technology has been well-known with automotive applications such as engine mounts, vehicle's main suspension system. In order to study the nature of the problem, structure of a hydraulic hybrid vehicle in series design is analyzed. The operational characteristics of the powertrain are carefully studied, and the vibration data is formulated. This research shows that not only MR elements play an important role in vibration suppression, but also the geometrical configurations of the mounting systems affect the efficiency in noise and vibration isolation. To this end, simulation results are also used to determine the most effective control method for the MR mounts.