【作者】 于洋磊；

【导师】 阮登芳； 曾志新；

【作者基本信息】 重庆大学 ， 车辆工程， 2018， 硕士

【摘要】 车内噪声是影响乘坐舒适性的重要原因,随着发动机、进排气等传统噪声的降低以及发动机启停、HEV、PHEV等技术的应用推广,作为车内噪声来源之一的燃油箱晃动噪声逐渐凸显,直接影响到消费者对于汽车的初步评价和总体印象。本文以某乘用车燃油箱为研究对象,在总结国内外有关燃油箱晃动及其噪声研究现状的基础上,从仿真及实验角度进行了分析改进。主要研究工作及结论如下:(1)对整车状态下燃油箱在不同充油量及不同行驶工况下的晃动噪声进行了主观评价。结果表明100%充油量时的蠕动行驶工况是燃油箱晃动噪声最为严重的工况,选此工况进行后续的仿真及实验。(2)基于STAR-CCM+软件建立了燃油箱晃动CFD模型,对不同充油量的燃油箱进行了蠕动工况下的油液晃动仿真。随时间变化的油液三维运动视图及燃油箱壁面最大压强分布均表明在100%充油量状态下的燃油箱油液晃动最为剧烈,与主观评价结果一致,同时也验证了仿真模型的准确性。(3)基于Abaqus软件建立了燃油箱FE(有限元)模型,通过与STAR-CCM+软件的耦合,对有无防浪板及三种不同结构防浪板的燃油箱进行油液晃动及结构动力学仿真,得到了燃油箱壁面的压力及振动加速度。结果表明,安装防浪板后燃油箱壁面最大压强及四个监测点的振动加速度均明显减小,振动加速度峰值最高减少50%以上,三种防浪板在四个监测点上的振动加速度均为左前监测点峰值最大,右后最小,综合选取最优的防浪板3安装在燃油箱上进行后续的整车实验。(4)在分析燃油箱晃动噪声传递路径的基础上,对安装防浪板3的燃油箱进行了整车状态下的实验,得到了蠕动工况下燃油箱本体、绑带、车身等部位的振动加速度值以及乘员舱内和油箱侧声压值。将燃油箱本体振动加速度测试值与仿真结果比较,结果表明两者吻合较好,且均为左前侧振动最大,右后侧振动最小;对于绑带及隔振垫处振动加速度,分析了其对燃油箱本体振动加速度传递的影响,针对燃油箱近场及乘员舱内部,进行了噪声分析,确定了晃动噪声的关键点在于燃油箱本体及隔振垫。(5)结合仿真及实验结果,对燃油箱结构从防浪板、燃油箱壳体、隔振垫等方面进行了改进设计。为验证改进的效果,通过油液晃动及结构动力学仿真进行改进前后的对比,改进后的燃油箱壁面振动加速度明显减小,尤其在右后监测点Z方向振动加速度减少了30.9%,从仿真角度确认了改进的可靠与有效。更多还原

【Abstract】 The noise in the vehicle is an important factor affecting the ride comfort.With the reduction of the traditional noise,such as engine noise,intake and exhaust noise,and the application and popularization of the engine start-stop,HEV,PHEV and other technologies,the sloshing noise of the fuel tank,as one of the internal noise sources of the vehicle,is gradually highlighted,which directly affects the initial evaluation and the general impression of the consumers for the automobile.In this paper,the fuel tank of a passenger car is taken as the research object.On the basis of summarizing the research status of the fuel tank sloshing and noise at home and abroad,the analysis and optimization are carried out from the point of view of simulation and experiment.The main research work and conclusions are as follows:(1)The subjective evaluation of the sloshing noise of different filling rates and different driving conditions was carried out for the fuel tank in the entire vehicle state.The results show that the sloshing noise in the creep driving condition of the 100% filling rate is the most serious.The following simulation and experiment were conducted in this filling rate and driving condition.(2)Based on the STAR-CCM+ software,the sloshing CFD model of the fuel tank was established.The sloshing simulations of the fuel tank with different filling rates were carried out in the creep driving condition.The three-dimensional motion view and the maximum pressure distribution of the fuel tank wall with the time change show that the fuel tank sloshing is the most violent in the 100% filling state,which is in accordance with the subjective evaluation results,and also verifies the accuracy of the simulation model.(3)Based on the Abaqus software,the fuel tank FE model is established.Through the coupling with the STAR-CCM+ software,the fuel tank sloshing and structural dynamics simulation were carried out for the fuel tanks with or without baffles and three different types of structural baffles.The pressure and vibration acceleration of the wall of the fuel tank under the different baffles are obtained.The results show that the maximum pressure on the wall of the fuel tank and the vibration acceleration of the four monitoring points are significantly reduced after the installation of the baffles,and the peak value of the vibration acceleration is reduced by more than 50%.The vibration acceleration peaks at the four monitoring points for the three types of baffles are both the left front monitoring point is the largest and the right rear is the smallest.The baffle 3 was selected to install on the fuel tank for the subsequent vehicle test.(4)On the basis of the analysis of the sloshing noise transmission path of the fuel tank,the experiment of the fuel tank installed with the baffle 3 was carried out.The vibration acceleration of the fuel tank body,the straps and the body,as well as the sound pressure in the cabin and the tank side under the creep driving condition were obtained,The vibration acceleration of the fuel tank body is compared with the simulation value,which is in good agreement,both of them have the largest vibrations on the left front side and the smallest vibrations on the right rear side,For the vibration accelerations of the straps and vibration isolation pads,their influence on the vibration acceleration transmission was analyzed,and the noise analysis is carried out in the near field of the fuel tank and the cabin of the crew.(5)According to the simulation and experimental results,the improved design of the fuel tank structure was made in terms of baffles,fuel tank shell,and vibration isolation cushions.To verify the improvement effect,comparisons were made before and after optimization through fuel sloshing and structural dynamics simulation.The vibration acceleration of the fuel tank wall after optimization was significantly reduced,especially in the right rear monitoring point,the Z-direction vibration acceleration was reduced by 30.9%,and the reliability and effectiveness of the optimization was confirmed from the simulation point of view.更多还原