A Review on Model and Control of Electromagnetic Active Engine Mounts

The isolation of the body from engine vibration is the most challenging and disruptive vibrational problem. Active engine mounts (AEMs), especially electromagnetic AEMs, achieve a significant performance improvement in decreasing the wide frequency band vibration. Increasing research interest is necessary to provide the academic community with a guideline for electromagnetic AEMs. Therefore, the current review aims to comprehensively supplement the review of AEMs. The key reviews of electromagnetic AEMs focus on (1) general considerations of electromagnetic AEMs, (2) models, and (3) control strategies. This paper presents a review of the current status and developmental progress of AEMs. A theoretical model, a finite-element model, and the identification (or experimental modelling) of electromagnetic AEMs during the last 2 decades are then studied. Finally, control strategies, such as classical control, adaptive control, and two degree of freedom (2DOF) control, are discussed and compared. The main purpose of this paper is to meet the needs of researchers and engineers engaged in electromagnetic AEM analysis and control.

Model of the Secondary Path between the Input Voltage and the Output Force of an Active Engine Mount on the Engine Side

The active engine mount (AEM) provides an effective solution to improve the acoustic and vibration comfort of a car. The same AEM can be installed for different engines and different vehicle bodies and attenuates the engine vibration, which is one of the most pressing challenges. To study this problem, this paper develops a mathematical model of a secondary path between the input voltage and output force of the AEM on the engine side considering the frequency-dependent characteristic of the stiffness, which includes the structure parameters of the AEM as well as the dynamics of the actuator, the fluid in the inertia track, the foundation (vehicle body), and the attenuated vibrating object (AEM preload or engine). The proposed model is validated by three test cases without vibration excitation, which are performed with different AEM preloads and foundations. The AEM is considered as an active part and passive part, the mass of which is determined experimentally. Parameter effect on the dynamic characteristics of the secondary path of the AEM is studied based on three tests and a numerical simulation.

Non-Linear Modeling and Parameter Identification of Semi-Active Engine Mounts With Air Spring

Car manufacturers have been motivated to apply semi-active engine mounts to ensure superior performance in vibration attenuation during idle condition and better ability to isolate vibration which is generated by engine unbalanced force at high frequencies. This paper develops a non-linear lumped parameter model of semi-active engine mounts with air spring that focuses on the non-linearity of the rubber diaphragm and the air chamber. Then, the main rubber dynamic stiffness parameters are identified through experimental approaches with a novel-designed test rig. Other parameters including effective pumping area, main rubber spring bulge stiffness, fluid channel inertia and resistance, rubber diaphragm, and air-chamber parameters are attained through finite element analysis (FEA). Supported by the identified lumped parameters, the non-linear mathematical model could be simulated. In addition, the dynamic characteristics of the semi-active engine mount are tested through the original test rig. Therefore, comparing with the tested dynamic characteristics, the simulation result can validate the developed model and thus facilitate the structure design of the semi-active engine mount.

Parametric identification study of an active engine mount: Combination of finite element analysis and experiment

An active engine mount (AEM) is an effective technology to improve a vehicle’s noise, vibration, and harshness performance. This paper mainly focuses on the combination experiment and finite element analysis (FEA) for parameter identification of AEMs. Notably, a novel test rig is designed to identify all specific parameters involved in the AEM. Firstly, the static and dynamic stiffness of the main rubber spring are calculated based on structure FEA method. The equivalent piston area and upper chamber volumetric stiffness are also estimated through fluid–structure interaction analysis. Inertia track parameters, involving inertia and linear and nonlinear resistance of the fluid, are identified by a simplified fluid model. These common hydraulic engine mount parameters are all experimentally validated through the original test rig. Besides, the particular components of the electromagnetic AEM, namely actuator parameters, are further estimated by experimental identification utilizing the experimental apparatus. The novel test bench, which exhibited high accuracy, good tightness, and strong versatility, not only simplifies the structure and process of identification plant for passive engine mount parameters, but accommodates the particular AEM ones. The combination method assimilates both the efficiency of FEA and the accuracy of experiment, facilitating the structure design and renovation of AEMs.