Research On Optimizing Design Of The Engine Mount System Of A Big Mini Van

China auto market becomes more and more mature. More and more attention is paid to the noise and vibration of the auto. It plays an important role in automobile design to isolate engine's vibration from transmitting to frame and automobile body. The practice and the theory proved that powertrain mounting system design is self-contradictory. On one hand, mounting system needs to have the high rigidity to limit engine's movement. On the other hand, mounting must be softly enough to provide a good vibration isolation performance. The target in this topic of powertrain mounting system vibration isolation performance optimization design research is find the most superior solution between limiting engine's oversized movement and optimalizing vibration isolation performance. The primary coverage of this research lists:1. Elaborated and summarized the domestic and foreign research situation as well as the research results about mounting parts,mounting system and the whole car comfort lying on mounting system. At the same time, summarized some kind of flows about the mounting system development and optimization, the mounting frame topology optimization.2. In the foundation of mounting-system dynamics simulation analysis, analyzed the stress and the modality frequency of mounting frame. Considering the situation of the pre-analysis, used the variable-density technique to carry on the topological-structure optimization to the components. Comparing the stress and the modality frequency, showed the topology optimization had remarkable effect regarding the mounting frame's lightweight and mechanical properties'improvement.3. Take some big mini van powertrain mounting system as the object of study. use the multi-island genetic algorithm and energy decoupling theory to carry on the optimization design to the powertrain mounting system's rigidity. Carry on the misalignment rigidity design and the structural design for rubber mounting parts according to the optimized structure. Check powertrain's displacement and the rotation angle in different operation condition. Export the load condition which would be used as the initial condition for the checking and optimization of mounting frames.4. Design reasonable parameters for some micro coach powertrain mounting system which is being developed. using topological-optimization technique, multi-island genetic algorithm as well as energy decoupling technique, carry on the matching design for that powertrain mounting system to meet the NVH requirement.5. Introduces the content of NVH tuning about the engine mounting system, the content of the engine mounting system evaluation are summarized. And take the vibration isolation rate of testing and spectrum test for the powertrain mounting system. Points out the follow-up development work to be done about the stdudy vehicle in this paper.During the research process mentioned above, there were some innovations in techniques list as follows:1) Summarized the design and development overview flow about powertrain mounting system. This article took the design theory and foundation technology in the dynamic analysis and improvement design about powertrain mounting system as a breakthrough point. Proposed the general techniqueflow after understanding internal relations about correlation techniques. It was the guiding principle through all over the following analysis and design research.2) Brought in multi-island genetic algorithm into powertrain-mounting system's optimization. It provided a new method for powertrain-mounting system's computation. The decoupling rate of powertrain-mounting system is sensitive to each input parameter's change in the decoupling process based on energy method, so that a set of appropriate optimization algorithm for calculating the decoupling rate was very essential.3) Brought in topological-optimization technique into the design and optimization of powertrain-mounting frames. Conventionally, mounting frames'design meant carrying on the computation merely to this frame's modality. In practical application, there were many requirements not only for modality,but also saving in material and reduction of cost. This article gained a better structure and modality performance while reducing components' weight and the cost via bringing in topological-optimization technique.