Magneto-rheological mount is one of the most effective vibration isolation devices for the vibration isolation system of vehicle powertrain. In this article, a flow type of magneto-rheological mount was proposed to control the vibration and the torque excitation of the engine when vehicle was in start/stop mode. A mathematical model for the flow type of magneto-rheological mount was formulated with consideration of the influence of current on magneto-rheological fluid viscosity and the relationship between liquid resistance effect and flow rate in damping gap. Then, a co-simulation optimal platform was developed by the Isight and the ANSYS, and the non-dominated sorting genetic algorithm II was used to optimize magnetic circuit. Subsequently, two prototypes of magneto-rheological mounts were manufactured according to the initial design and the optimal design model, and the dynamic performance test of magneto-rheological mount monomer and the vibration isolation performance test of the whole vehicle under start/stop mode were carried out, respectively. The experimental results showed that the controllability and the vibration isolation performance of the optimal design magneto-rheological mount were significantly improved compared with the initial design.

Mostly, magnetorheological (MR) dampers were optimized based on individual performance, without considering the influence of structure parameters change on vehicle performance. Therefore, a multi-objective optimization scheme of MR damper based on vehicle dynamics model was proposed. The finite element method was used to analyze magnetic flux density distribution in tapered damping channel under different structure parameters. Furthermore, the damping force expression of the tapered flow mode MR damper was derived, and the damping force was introduced into the vehicle dynamics model. In order to improve the ride comfort and operation stability of the vehicle, a collaborative optimization platform combining magnetic circuit finite element analysis and vehicle dynamics model was established. Based on this platform, the optimal design variables were determined by comfort and stability sensitivity analysis. The time domain optimization objective and frequency domain optimization objective are proposed simultaneously to overcome the lack of time domain optimization objective. The results show that compared with the time domain optimization and the initial design, the suspension dynamic deflection, tire dynamic load and vehicle body vertical acceleration are decreased after the time-frequency optimization. At the same time, in the frequency domain, the amplitude of vibration acceleration in each working condition is significantly reduced.

No abstract

In order to relieve saturation of magnetic flux density in magnetic circuit, the flow mode magnetorheological mount with tapered channel is designed. The influence of geometrical parameters of the damping channel on magnetic flux density and pressure drop is analysed. The key parameters have strong nonlinear relationship with magnetic field strength and pressure drop. Then, the parametric modelling of magnetic circuit structure was carried out using ANSYS software as the analysis system. The mount optimisation analysis model was built based on ISIGHT software. The optimisation results showed that the designed magnetorheological mount improved the saturation point of magnetic flux density of the damping channel, and the resulting pressure drop had good controllability.

Considering the influence of mount structure parameters on the quality of vehicle noise, vibration and harshness (NVH), a multi-objective optimization method of the magneto-rheological (MR) mount based on vehicle vibration control was proposed. A lumped parameter model was used to establish the relationship between the structure parameters of the MR mount and the NVH performance of the vehicle. Considering the influence of current on the magneto-rheological fluid viscosity and flow rate in damping channel, the dynamic characteristics of MR mount was obtained by the lumped parameter model. Then, a 10 degrees of freedom (DOF) vehicle model with MR mounting system was established. Finally, a co-simulation optimal platform was developed by the ISIGHT, MATLAB, and ANSYS software, and the non-dominated sorting genetic algorithm II was used to optimize the design of the mount magnetic circuit with the goal of improving the quality of vehicle NVH. The results showed that under the start/stop and the constant speed conditions, the root mean square values of vibration acceleration of the driver’s seat rail of the vehicle with the optimal design magneto-rheological mount decreases by 31.6% and 7.8%, respectively compared with the initial design mount, improved the ride comfort of the vehicle.