The Study Of Vibration Isolation Of Mount System Of Powertrain For A Model Of HEV

With the rapid development of automotive industry, the ride comfort is required more and more high by people. So the influence of vibration and noise of the powertrain to the ride comfort becomes more manifest. This dissertation studied the powertrain including the engine, the motor, the clutch and the transmission, which was made for The Geely Model HEV (Hybrid Electric Vehicle). Compared with the powertrain of the traditional vehicle, the powertrain of Geely Model HEV has an additional motor. Because the motor hasn't unbalanced force and torque not like the engine, the vibration of the engine is major factor and the vibration of the motor is minor factor comparatively. In addition, the design of the modern car put emphasis on reducing the weight and adopting new-type, high-strength, light-nature materials in order to minimize the mass of the whole vehicle, But it is very difficult to reduce the weight of the engine comparatively. Thus the proportion of the engine in the while weight of the vehicle is increased correspondingly, the factor makes the vibration of the engine more manifest. Because of shortage of engine sources, now most of the engine are four-stoke and four-in-line engine which have bad balance characteristic; most of the car use the integrity pattern and thin-cell-fabric body which leads to the increasing of the flexibility of the body, thus the vibration of the engine on the body increases comparatively. So, the vibration of the engine becomes the main vibration source of the car. The rotation torque oscillation which output by the engine and vertical reciprocating inertia force which produced by the piston not only excite the torsional and bending vibration of the transmission system but also stir all kinds of vibration of the car body and resonances noise of the cabin. So the vibration isolating characteristics of the engine mount system have a great influence on the ride comfort of the car. An engine mount system which is designed properly not only reduce the force which is transmitted to the car body and the noise, but also increase the ride comfort and protect the powertrain effectively.So, vibration isolation of automobile, especially vibration isolation of powertrain is kind of important technology of automotive design. Vibration affects not only the ride comfortableness, but also automobile's ride stability and safety. Proper design of automotive powertrain would greatly reduce the vibration of automotive powertrain and body. This dissertation takes the Geely Hybrid-Electric Concept Vehicle as the research objective, systematically studies the vibration isolation performance of the powertrain mounting system. The following subjects are studied:1. Based on a large number of references about the study of powertrain mounting, this dissertation systematically discusses the research history of powertrain mount, and deeply researches on the history of the development of mounting system. At the same time, this dissertation summarizes some principle and requirements of design and optimization design.2. The basic parameters of the powertrain mount system are measured by the method of experiments and calculation., simply introduce the certainty of mass center and mass inertia quadrature, and the experimental results are obtained finally.3. Based on Multi-Body Dynamic theory and vibration theory, according of the mass parameters and geometry position parameters of each component in real model, using the software of Pro/e to build three-dimensional model of the powertrain mount system, then under the help of the software Mechpro2005, put the three-dimensional model of the powertrain mount system into the software of ADAMS, Finally, under the condition of only engine working, only motor working and the both working, this dissertation applies the software modules of ADAMS/View and ADAMS/Vibration to analyze the isolation performance in time domain and in frequency domain from different angle. From the analysis, we get some useful conclusions. In addition, the dissertation gives the method of how to realize the rubber mount and the hydraulic mount, and simulate the characteristic of hydraulic mount and the exciting force of engine.4. The dissertation takes the minimum sum of dynamic force of left, right and rear mounts as the optimization objective, and takes the parameters of the three mounts as parameter variables, systematically optimize the powertrain system, and get the satisfied results.