【作者】 张洋；

【导师】 焦映厚；

【作者基本信息】 哈尔滨工业大学 ， 机械设计及理论， 2011， 硕士

【摘要】 汽车动力总成是汽车振动的主要激振源之一,对汽车操作稳定性和乘坐舒适性有很大影响。针对大型客车的动力总成悬置系统设计研究较少,目前的客车发动机主要采用被动的橡胶悬置系统隔振,它难以满足发动机宽频范围内隔振降噪的要求。本文提出新型磁流变液压悬置系统,对其进行设计分析,运用模糊控制方法实现阻尼的可调性。对整车的隔振降噪水平具有一定的指导意义。本文根据某国产大型客车动力总成的结构和工作特点,建立系统六自由度动力学模型。该模型直观反映了客车四点、斜置的动力总成悬置系统,并根据四缸四冲程直列发动机作为激振源的系统外力,推导并求解系统运动微分方程。研究发动机隔振效果的评价指标,分析被动橡胶悬置系统动特性,得出发动机宽频隔振要求。设计了新型磁流变液压悬置。该悬置将被动液压悬置中的液压油替换为磁流变液,利用这种智能材料的流变特性实现阻尼的实时调控。分析该悬置的具体结构和工作原理,确定各个零部件的材料、设计尺寸和参数。分析该动力总成磁流变液压悬置系统六阶模态及固有频率、稳态振动响应和特殊工况下的瞬态振动响应,验证动力总成磁流变液压悬置系统具有隔离发动机及车身之间双向振动传递的作用。提出将模糊控制思想融入动力总成磁流变液压悬置系统的方法,对其进行模糊控制研究。根据发动机宽频隔振要求,设计模糊控制策略和模糊控制器。对比分析了采用模糊控制的磁流变液压悬置、未加控制的磁流变液压悬置和橡胶悬置的隔振效果,验证模糊控制下的磁流变液压悬置隔振效果较被动悬置有所改进,阻尼可实时调控,能够在宽频范围内有效隔振。更多还原

【Abstract】 Vehicle powertrain is the main exciting source of vibration, which has a significant impact on the stability and comfort of vehicle operations. There is little powertrain mounting system study for arge passenger vehicles , the current bus engine is mainly passive rubber mounting system, which is difficult to meet the range of the engine vibration noise broadband requirements. This paper presents new MRF hydraulic suspension system. the adjustable damping is achieved by the use of fuzzy control ,which has has a guiding sense for descreasing Noise level of vehicle vibration .The six degrees of freedom dynamic model of the system is established,Based on a domestic passenger car structure and characteristics of the powertrain . The model directly reflects the four-point bus, oblique powertrain mounting system.the system of differential equations of motion is derived in accordance with four-cylinder four-stroke inline engine system as the external excitation source . the current use of the passive rubber engine mounting system can not meet the requirements of broadband noise isolation. Compare and analyze that the current passive rubber engine mounting system can’t meet the requirements of the engine isolating vibration and noise.The new engine MRF hydraulic mounting is designed,which meets Requirement of Broadband vibration isolation . the hydraulic oil fluid is replaced by MRF in The passive hydraulic mounting, which can achieve real-time damping control.Analyze the specific structure,working principle, the components of the materials, design dimensions and parameters.we also analyze the hydraulic of powertrain mounting system , six-step mode natural frequency, steady state vibration response and special conditions of the transient vibration response.Finally, the fuzzy control theory is fused in the hydraulic powertrain mounting system, according to broadband engine vibration isolation requirements, fuzzy control strategy and fuzzy controller are designed.The paper compared the fuzzy control of the magnetorheological hydraulic suspension and uncontrolled magnetorheological hydraulic suspension and rubber mounts for vibration.Verify that the magnetorheological hydraulic mount with the fuzzy control has an improvement over the passive mounting system. Its damp can be controlled as real-time, and it can be effective in isolation within the broadband.更多还原