Abstract: In order to study the dynamic characteristics of automobile radiator,according to the measured amplitude frequency characteristic curve of the radiator,the radiator is simplified to three degree of freedom dynamics model,using orthogonal polynomial fitting method and physical parameters step by step optimization method for the identification of dynamic model.The research results show that the amplitude frequency characteristic curve of the radiator dynamics identification of the model parameters is consistent with the actual test,the average error of the natural frequency is 5.1 %,the average error of the amplitude is 6.9 %.

Key words: radiator, dynamic characteristics, dynamic model, parameter identification