The launch shudder phenomenon induced by self-excited vibration of driveline was stud- ied with a compact car equipped with AMT as research object. The research showed that self-excited vibration was closely related w...The launch shudder phenomenon induced by self-excited vibration of driveline was stud- ied with a compact car equipped with AMT as research object. The research showed that self-excited vibration was closely related with damping of driveline, the variation of friction coefficient, equiva- lent radius of friction plate and applied force of pressure plate. Six DOFs torsional vibration model of vehicle driveline was established according to the parameters of the certain compact car. The simula- tion was carried out and the result was compared with test data. It was found that the negative slope of friction coefficient with relative slip speed does not necessarily lead to self-excited vibration and the frequency of self-excited vibration on 1st gear is near to the 1st order of torsional natural frequen- cy. The influence of each viscous damping in driveline on self-excited vibration was analyzed by sim- ulation and the results showed that increasing the torsional dampings of half-axles and tires properly was effective to improve launch shudder phenomenon.展开更多
通过对汽车起步颤振现象的实车坡道实验,指出了基于短时傅里叶变换(Short Time Fourier Transform,STFT)进行分析的不足之处.然后采用34种不同的小波基函数,对原始振动信号进行小波分析及滤波,仅保留了低频的振动信息,最后通过降低采样...通过对汽车起步颤振现象的实车坡道实验,指出了基于短时傅里叶变换(Short Time Fourier Transform,STFT)进行分析的不足之处.然后采用34种不同的小波基函数,对原始振动信号进行小波分析及滤波,仅保留了低频的振动信息,最后通过降低采样频率,对滤波后的信号重采样并分析,发现采用dmey(Discrete Meyer wavelet)小波进行滤波及重采样后的结果,对本实验0-20Hz频域内信息的误差最小,并且较好地保留了原信号在该频域内的频谱特性.展开更多
针对某多用途汽车(multi-purpose vehicles,MPV)车辆小油门加速时整车纵向振动问题,深入研究了发动机激励及传动系扭振特性对车辆瞬态加速平顺性的影响,并提出优化方法。通过搭建整车传动系纵向振动耦合模型,将实际发动机工作载荷及油...针对某多用途汽车(multi-purpose vehicles,MPV)车辆小油门加速时整车纵向振动问题,深入研究了发动机激励及传动系扭振特性对车辆瞬态加速平顺性的影响,并提出优化方法。通过搭建整车传动系纵向振动耦合模型,将实际发动机工作载荷及油门信号作为系统激励进行计算分析,从而判断振动是由转矩瞬态变化激起传动系刚体扭转模态产生;分析锁定关键影响参数并进行贡献量分析,从硬件角度提出了离合器阻尼、刚度优化,半轴扭转刚度提升等方案;同时综合平衡动力性、油耗、平顺性等性能,从软件控制策略角度提出电控单元(electronic control unit,ECU)的转矩参考滤波的方案,通过调整滤波参数使转矩输出平缓从而减少不平顺性。各项优化方案经实车验证能有效提升整车加速纵向平顺性能。展开更多
基金Supported by the National Natural Science Foundation of China(51175379)
文摘The launch shudder phenomenon induced by self-excited vibration of driveline was stud- ied with a compact car equipped with AMT as research object. The research showed that self-excited vibration was closely related with damping of driveline, the variation of friction coefficient, equiva- lent radius of friction plate and applied force of pressure plate. Six DOFs torsional vibration model of vehicle driveline was established according to the parameters of the certain compact car. The simula- tion was carried out and the result was compared with test data. It was found that the negative slope of friction coefficient with relative slip speed does not necessarily lead to self-excited vibration and the frequency of self-excited vibration on 1st gear is near to the 1st order of torsional natural frequen- cy. The influence of each viscous damping in driveline on self-excited vibration was analyzed by sim- ulation and the results showed that increasing the torsional dampings of half-axles and tires properly was effective to improve launch shudder phenomenon.
文摘针对某多用途汽车(multi-purpose vehicles,MPV)车辆小油门加速时整车纵向振动问题,深入研究了发动机激励及传动系扭振特性对车辆瞬态加速平顺性的影响,并提出优化方法。通过搭建整车传动系纵向振动耦合模型,将实际发动机工作载荷及油门信号作为系统激励进行计算分析,从而判断振动是由转矩瞬态变化激起传动系刚体扭转模态产生;分析锁定关键影响参数并进行贡献量分析,从硬件角度提出了离合器阻尼、刚度优化,半轴扭转刚度提升等方案;同时综合平衡动力性、油耗、平顺性等性能,从软件控制策略角度提出电控单元(electronic control unit,ECU)的转矩参考滤波的方案,通过调整滤波参数使转矩输出平缓从而减少不平顺性。各项优化方案经实车验证能有效提升整车加速纵向平顺性能。
